Sample records for lake mohave colorado

  1. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Mohave (Colorado River), Ariz.-Nev. 162.220 Section 162.220 Navigation and Navigable Waters COAST GUARD... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and... the axis of Hoover Dam and that portion of Lake Mohave (Colorado River) extending 4,500 feet...

  2. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and... the axis of Hoover Dam and that portion of Lake Mohave (Colorado River) extending 4,500 feet...

  3. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and... the axis of Hoover Dam and that portion of Lake Mohave (Colorado River) extending 4,500 feet...

  4. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and... the axis of Hoover Dam and that portion of Lake Mohave (Colorado River) extending 4,500 feet...

  5. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and... the axis of Hoover Dam and that portion of Lake Mohave (Colorado River) extending 4,500 feet...

  6. Lake Mohave Geophysical Survey 2002: GIS Data Release

    USGS Publications Warehouse

    Cross, VeeAnn A.; Foster, David S.; Twichell, David C.

    2005-01-01

    This CD-ROM contains sidescan-sonar imagery, sub-bottom reflection profiles, and an interpretive map derived from these data. These data were collected in Lake Mohave, a reservoir behind the Davis Dam and below the Hoover Dam on the Colorado River. These data are veiwable within an Environmental system Research Institute, Inc. (ESRI) Geographic Information system (GIS) ArcView 3.2 project file stored on this CD-ROM

  7. Paleogeomorphology of the early Colorado River inferred from relationships in Mohave and Cottonwood Valleys, Arizona, California and Nevada

    USGS Publications Warehouse

    Pearthree, Philip; House, P. Kyle

    2014-01-01

    Geologic investigations of late Miocene–early Pliocene deposits in Mohave and Cottonwood valleys provide important insights into the early evolution of the lower Colorado River system. In the latest Miocene these valleys were separate depocenters; the floor of Cottonwood Valley was ∼200 m higher than the floor of Mohave Valley. When Colorado River water arrived from the north after 5.6 Ma, a shallow lake in Cottonwood Valley spilled into Mohave Valley, and the river then filled both valleys to ∼560 m above sea level (asl) and overtopped the bedrock divide at the southern end of Mohave Valley. Sediment-starved water spilling to the south gradually eroded the outlet as siliciclastic Bouse deposits filled the lake upstream. When sediment accumulation reached the elevation of the lowering outlet, continued erosion of the outlet resulted in recycling of stored lacustrine sediment into downstream basins; depth of erosion of the outlet and upstream basins was limited by the water levels in downstream basins. The water level in the southern Bouse basin was ∼300 m asl (modern elevation) at 4.8 Ma. It must have drained and been eroded to a level <150 m asl soon after that to allow for deep erosion of bedrock divides and basins upstream, leading to removal of large volumes of Bouse sediment prior to massive early Pliocene Colorado River aggradation. Abrupt lowering of regional base level due to spilling of a southern Bouse lake to the Gulf of California could have driven observed upstream river incision without uplift. Rapid uplift of the entire region immediately after 4.8 Ma would have been required to drive upstream incision if the southern Bouse was an estuary.

  8. A synthesis of aquatic science for management of Lakes Mead and Mohave

    USGS Publications Warehouse

    Rosen, Michael R.; Turner, Kent; Goodbred, Steven L.; Miller, Jennell M.

    2012-01-01

    Lakes Mead and Mohave, which are the centerpieces of Lake Mead National Recreation Area, provide many significant benefits that have made the modern development of the Southwestern United States possible. Lake Mead is the largest reservoir by volume in the nation and it supplies critical storage of water supplies for more than 25 million people in three Western States (California, Arizona, and Nevada). Storage within Lake Mead supplies drinking water and the hydropower to provide electricity for major cities including Las Vegas, Phoenix, Los Angeles, Tucson, and San Diego, and irrigation of more than 2.5 million acres of croplands. Lake Mead is arguably the most important reservoir in the nation because of its size and the services it delivers to the Western United States. This Circular includes seven chapters. Chapter 1 provides a short summary of the overall findings and management implications for Lakes Mead and Mohave that can be used to guide the reader through the rest of the Circular. Chapter 2 introduces the environmental setting and characteristics of Lakes Mead and Mohave and provides a brief management context of the lakes within the Colorado River system as well as overviews of the geological bedrock and sediment accumulations of the lakes. Chapter 3 contains summaries of the operational and hydrologic characteristics of Lakes Mead and Mohave. Chapter 4 provides information on water quality, including discussion on the monitoring of contaminants and sediments within the reservoirs. Chapter 5 describes aquatic biota and wildlife, including food-web dynamics, plankton, invertebrates, fish, aquatic birds, and aquatic vegetation. Chapter 6 outlines threats and stressors to the health of Lake Mead aquatic ecosystems that include a range of environmental contaminants, invasive species, and climate change. Chapter 7 provides a more detailed summary of overall findings that are presented in Chapter 1; and it contains a more detailed discussion on associated

  9. Geologic map of the Mohave Mountains area, Mohave County, western Arizona

    USGS Publications Warehouse

    Howard, K.A.; Nielson, J.E.; Wilshire, W.G.; Nakata, J.K.; Goodge, J.W.; Reneau, Steven L.; John, Barbara E.; Hansen, V.L.

    1999-01-01

    Introduction The Mohave Mountains area surrounds Lake Havasu City, Arizona, in the Basin and Range physiographic province. The Mohave Mountains and the Aubrey Hills form two northwest-trending ranges adjacent to Lake Havasu (elevation 132 m; 448 ft) on the Colorado River. The low Buck Mountains lie northeast of the Mohave Mountains in the alluviated valley of Dutch Flat. Lowlands at Standard Wash separate the Mohave Mountains from the Bill Williams Mountains to the southeast. The highest point in the area is Crossman Peak in the Mohave Mountains, at an elevation of 1519 m (5148 ft). Arizona Highway 95 is now rerouted in the northwestern part of the map area from its position portrayed on the base map; it now also passes through the southern edge of the map area. Geologic mapping was begun in 1980 as part of a program to assess the mineral resource potential of Federal lands under the jurisdiction of the U.S. Bureau of Land Management (Light and others, 1983). Mapping responsibilities were as follows: Proterozoic and Mesozoic rocks, K.A. Howard; dikes, J.K. Nakata; Miocene section, J.E. Nielson; and surficial deposits, H.G. Wilshire. Earlier geologic mapping includes reconnaissance mapping by Wilson and Moore (1959). The present series of investigations has resulted in reports on the crystalline rocks and structure (Howard and others, 1982a), dikes (Nakata, 1982), Tertiary stratigraphy (Pike and Hansen, 1982; Nielson, 1986; Nielson and Beratan, 1990), surficial deposits (Wilshire and Reneau, 1992), tectonics (Howard and John, 1987; Beratan and others, 1990), geophysics (Simpson and others, 1986), mineralization (Light and McDonnell, 1983; Light and others, 1983), field guides (Nielson, 1986; Howard and others, 1987), and geochronology (Nakata and others, 1990; Foster and others, 1990).

  10. Gasoline-Related Compounds in Lakes Mead and Mohave, Nevada, 2004-06

    USGS Publications Warehouse

    Lico, Michael S.; Johnson, B. Thomas

    2007-01-01

    The distribution of man-made organic compounds, specifically gasoline-derived compounds, was investigated from 2004 to 2006 in Lakes Mead and Mohave and one of its tributary streams, Las Vegas Wash. Compounds contained in raw gasoline (benzene, toluene, ethylbenzene, xylenes; also known as BTEX compounds) and those produced during combustion of gasoline (polycyclic aromatic hydrocarbon compounds; also known as PAH compounds) were detected at every site sampled in Lakes Mead and Mohave. Water-quality analyses of samples collected during 2004-06 indicate that motorized watercraft are the major source of these organic compounds to the lakes. Concentrations of BTEX increase as the boating season progresses and decrease to less than detectable levels during the winter when few boats are on the water. Volatilization and microbial degradation most likely are the primary removal mechanisms for BTEX compounds in the lakes. Concentrations of BTEX compounds were highest at sampling points near marinas or popular launching areas. Methyl tert-butyl ether (MTBE) was detected during 2004 but concentrations decreased to less than the detection level during the latter part of the study; most likely due to the removal of MTBE from gasoline purchased in California. Distribution of PAH compounds was similar to that of BTEX compounds, in that, concentrations were highest at popular boating areas and lowest in areas where fewer boats traveled. PAH concentrations were highest at Katherine Landing and North Telephone Cove in Lake Mohave where many personal watercraft with carbureted two-stroke engines ply the waters. Lake-bottom sediment is not a sink for PAH as indicated by the low concentrations detected in sediment samples from both lakes. PAH compounds most likely are removed from the lakes by photochemical degradation. PAH compounds in Las Vegas Wash, which drains the greater Las Vegas metropolitan area, were present in relatively high concentrations in sediment from the upstream

  11. The project MOHAVE tracer study: study design, data quality, and overview of results

    NASA Astrophysics Data System (ADS)

    Green, Mark C.

    In the winter and summer of 1992, atmospheric tracer studies were conducted in support of project MOHAVE, a visibility study in the southwestern United States. The primary goal of project MOHAVE is to determine the effects of the Mohave power plant and other sources upon visibility at Grand Canyon National Park. Perfluorocarbon tracers (PFTs) were released from the Mohave power plant and other locations and monitored at about 30 sites. The tracer data are being used for source attribution analysis and for evaluation of transport and dispersion models and receptor models. Collocated measurements showed the tracer data to be of high quality and suitable for source attribution analysis and model evaluation. The results showed strong influences of channeling by the Colorado River canyon during both winter and summer. Flow from the Mohave power plant was usually to the south, away from the Grand Canyon in winter and to the northeast, toward the Grand Canyon in summer. Tracer released at Lake Powell in winter was found to often travel downstream through the entire length of the Grand Canyon. Data from summer tracer releases in southern California demonstrated the existence of a convergence zone in the western Mohave Desert.

  12. Stratigraphic evidence for the role of lake spillover in the inception of the lower Colorado River in southern Nevada and western Arizona

    USGS Publications Warehouse

    House, P.K.; Pearthree, P.A.; Perkins, M.E.

    2008-01-01

    Late Miocene and early Pliocene sediments exposed along the lower Colorado River near Laughlin, Nevada, contain evidence that establishment of this reach of the river after 5.6 Ma involved flooding from lake spillover through a bedrock divide between Cottonwood Valley to the north and Mohave Valley to the south. Lacustrine marls interfingered with and conformably overlying a sequence of post-5.6 Ma finegrained valley-fill deposits record an early phase of intermittent lacustrine inundation restricted to Cottonwood Valley. Limestone, mud, sand, and minor gravel of the Bouse Formation were subsequently deposited above an unconformity. At the north end of Mohave Valley, a coarse-grained, lithologically distinct fluvial conglomerate separates subaerial, locally derived fan deposits from subaqueous deposits of the Bouse Formation. We interpret this key unit as evidence for overtopping and catastrophic breaching of the paleodivide immediately before deep lacustrine inundation of both valleys. Exposures in both valleys reveal a substantial erosional unconformity that records drainage of the lake and predates the arrival of sediment of the through-going Colorado River. Subsequent river aggradation culminated in the Pliocene between 4.1 and 3.3 Ma. The stratigraphic associations and timing of this drainage transition are consistent with geochemical evidence linking lacustrine conditions to the early Colorado River, the timings of drainage integration and canyon incision on the Colorado Plateau, the arrival of Colorado River sand at its terminus in the Salton Trough, and a downstream-directed mode of river integration common in areas of crustal extension. ?? 2008 The Geological Society of America.

  13. An evaluation of the evolution of the latest miocene to earliest pliocene bouse lake system in the lower Colorado river valley, southwestern USA

    USGS Publications Warehouse

    Spencer, J.E.; Pearthree, P.A.; House, P.K.

    2008-01-01

    The upper Miocene to lower Pliocene Bouse Formation in the lower Colorado River trough of the American Southwest was deposited in three basins - from north to south, the Mohave, Havasu, and Blythe Basins - that were formed by extensional fault ing in the early to middle Miocene. Fossils of marine, brackish, and freshwater organ isms in the Bouse Formation have been interpreted to indicate an estuarine environment associated with early opening of the nearby Gulf of California. Regional uplift since 5 Ma is required to position the estuarine Bouse Formation at present elevations as high as 555 m, where greater uplift is required in the north. We present a compilation of Bouse Formation elevations that is consistent with Bouse deposition in lakes, with an abrupt 225 m northward increase in maximum Bouse elevations at Topock gorge north of Lake Havasu. Within Blythe and Havasu Basins, maximum Bouse elevations are 330 m above sea level in three widely spaced areas and reveal no evidence of regional tilting. To the north in Mohave Basin, numerous Bouse outcrops above 480 m elevation include three widely spaced sites where the Bouse Formation is exposed at 536-555 m. Numerical simulations of initial Colorado River inflow to a sequence of closed basins along the lower Colorado River corridor model a history of lake filling, spilling, evaporation and salt concentration, and outflow-channel incision. The simulations support the plausibility of evaporative concentration of Colorado River water to seawater-level salinities in Blythe Basin and indicate that such salinities could have remained stable for as long as 20-30 k.y. We infer that fossil marine organ isms in the Bouse Formation, restricted to the southern (Blythe) basin, reflect coloniza tion of a salty lake by a small number of species that were transported by birds.

  14. Geohydrologic reconnaissance of Lake Mead National Recreation Area; Las Vegas Wash to Opal Mountain, Nevada

    USGS Publications Warehouse

    Laney, R.L.

    1981-01-01

    The study is a geohydrologic reconnaissance of about 170 square miles in the Lake Mead National Recreation Area from Las Vegas Wash to Opal Mountain, Nevada. The study is one of a series that describes the geohydrology of the recreation area and that indentifies areas where water supplies can be developed. Precipitation in this arid area is about 5 inches per year. Streamflow is seasonal and extremely variable except for that in the Colorado River, which adjoins the area. Pan evaporation is more than 20 times greater than precipitation; therefore, regional ground-water supplies are meager except near the Colorado River, Lake Mead, and Lake Mohave. Large ground-water supplies can be developed near the river and lakes, and much smaller supplies may be obtained in a few favorable locations farther from the river and lakes. Ground water in most of the areas probably contains more than 1,000 milligrams per liter of dissolved solids, but water that contains less than 1,000 milligrams per liter of dissolved solids can be obtained within about 1 mile of the lakes. Crystalline rocks of metamorphic, intrusive and volcanic origin crop out in the area. These rocks are overlain by conglomerate and mudstone of the Muddy Creek Formation, gravel and conglomerate of the older alluvium, and sand and gravel of the Chemehuevi Formation and younger alluvium. The crystalline rocks, where sufficiently fractured, yield water to springs and would yield small amounts of water to favorably located wells. The poorly cemented and more permeable beds of the older alluvium, Chemehuevi Formation, and younger alluvium are the better potential aquifers, particularly along the Colorado River and Lakes Mead and Mohave. Thermal springs in the gorge of the Colorado River south of Hoover Dam discharge at least 2,580 acre-feet per year of water from the volcanic rocks and metamorphic and plutonic rocks. The discharge is much greater than could be infiltrated in the drainage basin above the springs

  15. Measurements of Humidity in the Atmosphere and Validation Experiments (Mohave, Mohave II): Results Overview

    NASA Technical Reports Server (NTRS)

    Leblanc, Thierry; McDermid, Iain S.; McGee, Thomas G.; Twigg, Laurence W.; Sumnicht, Grant K.; Whiteman, David N.; Rush, Kurt D.; Cadirola, Martin P.; Venable, Demetrius D.; Connell, R.; hide

    2008-01-01

    The Measurements of Humidity in the Atmosphere and Validation Experiments (MOHAVE, MOHAVE-II) inter-comparison campaigns took place at the Jet Propulsion Laboratory (JPL) Table Mountain Facility (TMF, 34.5(sup o)N) in October 2006 and 2007 respectively. Both campaigns aimed at evaluating the capability of three Raman lidars for the measurement of water vapor in the upper troposphere and lower stratosphere (UT/LS). During each campaign, more than 200 hours of lidar measurements were compared to balloon borne measurements obtained from 10 Cryogenic Frost-point Hygrometer (CFH) flights and over 50 Vaisala RS92 radiosonde flights. During MOHAVE, fluorescence in all three lidar receivers was identified, causing a significant wet bias above 10-12 km in the lidar profiles as compared to the CFH. All three lidars were reconfigured after MOHAVE, and no such bias was observed during the MOHAVE-II campaign. The lidar profiles agreed very well with the CFH up to 13-17 km altitude, where the lidar measurements become noise limited. The results from MOHAVE-II have shown that the water vapor Raman lidar will be an appropriate technique for the long-term monitoring of water vapor in the UT/LS given a slight increase in its power-aperture, as well as careful calibration.

  16. 78 FR 71493 - Special Local Regulation; Lake Havasu City Christmas Boat Parade of Lights; Colorado River; Lake...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ...-AA00 Special Local Regulation; Lake Havasu City Christmas Boat Parade of Lights; Colorado River; Lake... Boat Parade of Lights on the Colorado River. This modification is necessary to reflect the actual dates... of Lights will involve fifty vessels in Lake Havasu, AZ transiting Thompson Bay, proceeding through...

  17. Application of Geographic Information System Methods to Identify Areas Yielding Water that will be Replaced by Water from the Colorado River in the Vidal and Chemehuevi Areas, California, and the Mohave Mesa Area, Arizona

    USGS Publications Warehouse

    Spangler, Lawrence E.; Angeroth, Cory E.; Walton, Sarah J.

    2008-01-01

    Relations between the elevation of the static water level in wells and the elevation of the accounting surface within the Colorado River aquifer in the vicinity of Vidal, California, the Chemehuevi Indian Reservation, California, and on Mohave Mesa, Arizona, were used to determine which wells outside the flood plain of the Colorado River are presumed to yield water that will be replaced by water from the Colorado River. Wells that have a static water-level elevation equal to or below the elevation of the accounting surface are presumed to yield water that will be replaced by water from the Colorado River. Geographic Information System (GIS) interpolation tools were used to produce maps of areas where water levels are above, below, and near (within ? 0.84 foot) the accounting surface. Calculated water-level elevations and interpolated accounting-surface elevations were determined for 33 wells in the vicinity of Vidal, 16 wells in the Chemehuevi area, and 35 wells on Mohave Mesa. Water-level measurements generally were taken in the last 10 years with steel and electrical tapes accurate to within hundredths of a foot. A Differential Global Positioning System (DGPS) was used to determine land-surface elevations to within an operational accuracy of ? 0.43 foot, resulting in calculated water-level elevations having a 95-percent confidence interval of ? 0.84 foot. In the Vidal area, differences in elevation between the accounting surface and measured water levels range from -2.7 feet below to as much as 17.6 feet above the accounting surface. Relative differences between the elevation of the water level and the elevation of the accounting surface decrease from west to east and from north to south. In the Chemehuevi area, differences in elevation range from -3.7 feet below to as much as 8.7 feet above the accounting surface, which is established at 449.6 feet in the vicinity of Lake Havasu. In all of the Mohave Mesa area, the water-level elevation is near or below the

  18. Floodplain lakes and alluviation cycles of the lower Colorado River

    NASA Astrophysics Data System (ADS)

    Malmon, D.; Felger, T. J.; Howard, K. A.

    2007-05-01

    The broad valleys along the lower Colorado River contain numerous bodies of still water that provide critical habitat for bird, fish, and other species. This chain of floodplain lakes is an important part of the Pacific Flyway - the major north-south route of travel for migratory birds in the western Hemisphere - and is also used by many resident bird species. In addition, isolated floodplain lakes may provide the only viable habitat for endangered native fish such as the razorback sucker, vulnerable to predation by introduced species in the main stem of the Colorado River. Floodplain lakes typically occupy former channel courses of the river and formed as a result of river meandering or avulsion. Persistent fluvial sediment deposition (aggradation) creates conditions that favor rapid formation and destruction of floodplain lakes, while long term river downcutting (degradation) inhibits their formation and evolution. New radiocarbon dates from wood recovered from drill cores near Topock, AZ indicate that the river aggraded an average of 3 mm/yr in the middle and late Holocene. Aggradational conditions before Hoover Dam was built were associated with rapid channel shifting and frequent lake formation. Lakes had short life spans due to rapid infilling with fine-grained sediment during turbid floods on the unregulated Colorado River. The building of dams and of armored banks had a major impact on floodplain lakes, not only by drowning large portions of the valley beneath reservoirs, but by preventing new lake formation in some areas and accelerating it in others. GIS analyses of three sets of historical maps show that both the number and total area of isolated (i.e., not linked to the main channel by a surface water connection) lakes in the lower Colorado River valley increased between 1902 and the 1950s, and then decreased though the 1970s. River bed degradation below dams inhibits channel shifting and floodplain lake formation, and the capture of fines behind the

  19. 78 FR 57173 - Notice of Availability of the Record of Decision for the Mohave County Wind Farm Project, Mohave...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-17

    ... generated by the Project. The approved Project includes up to 243 wind turbine generators and associated..., operation, maintenance, and decommissioning of the Project to BP Wind Energy; and for the BLM to issue a ROW...; AZA32315AA] Notice of Availability of the Record of Decision for the Mohave County Wind Farm Project, Mohave...

  20. Preliminary groundwater flow model of the basin-fill aquifers in Detrital, Hualapai, and Sacramento Valleys, Mohave County, northwestern Arizona

    USGS Publications Warehouse

    Tillman, Fred D.; Garner, Bradley D.; Truini, Margot

    2013-01-01

    Preliminary numerical models were developed to simulate groundwater flow in the basin-fill alluvium in Detrital, Hualapai, and Sacramento Valleys in northwestern Arizona. The purpose of this exercise was to gather and evaluate available information and data, to test natural‑recharge concepts, and to indicate directions for improving future regional groundwater models of the study area. Both steady-state and transient models were developed with a single layer incorporating vertically averaged hydraulic properties over the model layer. Boundary conditions for the models were constant-head cells along the northern and western edges of the study area, corresponding to the location of the Colorado River, and no-flow boundaries along the bedrock ridges that bound the rest of the study area, except for specified flow where Truxton Wash enters the southern end of Hualapai Valley. Steady-state conditions were simulated for the pre-1935 period, before the construction of Hoover Dam in the northwestern part of the model area. Two recharge scenarios were investigated using the steady-state model—one in which natural aquifer recharge occurs directly in places where water is available from precipitation, and another in which natural aquifer recharge from precipitation occurs in the basin-fill alluvium that drains areas of available water. A transient model with 31 stress periods was constructed to simulate groundwater flow for the period 1935–2010. The transient model incorporates changing Colorado River, Lake Mead, and Lake Mohave water levels and includes time-varying groundwater withdrawals and aquifer recharge. Both the steady-state and transient models were calibrated to available water-level observations in basin-fill alluvium, and simulations approximate observed water-level trends throughout most of the study area.

  1. Measurements of Humidity in the Atmosphere: Validation Experiments (MOHAVE I and MOHAVE II). Results Overview and Implication for the Long-Term Lidar Monitoring of Water Vapor in the UT/LS

    NASA Technical Reports Server (NTRS)

    Leblanc, Thierry; McDermid, I. S.; Vomel, H.; Whiteman, D.; Twigg, Larry; McGee, T. G.

    2008-01-01

    1. MOHAVE+MOHAVE II = very successful. 2. MOHAVE -> Fluorescence was found to be inherent to all three participating lidars. 3. MOHAVE II -> Fluorescence was removed and agreement with CFH was extremely good up to 16-18 km altitude. 4. MOHAVE II -> Calibration tests revealed unsuspected shortfalls of widely used techniques, with important implications for their applicability to longterm measurements. 5. A factor of 5 in future lidar signal-to-noise ratio is reasonably achievable. When this level is achieved water vapor Raman lidar will become a key instrument for the long-term monitoring of water vapor in the UT/LS

  2. 75 FR 38754 - Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-06

    ...-AA00 Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ AGENCY: Coast Guard, DHS... navigable waters of Lake Havasu on the lower Colorado River in support of the IJSBA World Finals. This... International Jet Sports Boating Association is sponsoring the IJSBA World Finals. The event will consist of 300...

  3. The white-margined penstemon (Penstemon albomarginatus Jones), a rare Mohave Desert species, and the Hualapai Mountains land exchange in Mohave County, Arizona

    Treesearch

    John L. Anderson

    2001-01-01

    The white-margined penstemon (Penstemon albomarginatus Jones) is a rare Mohave Desert species with an unusual tripartite distribution with disjunct localities in Arizona, California, and Nevada. The Arizona population is the largest single population occurring with a range of 15 miles by 5 miles in Dutch Flat near Yucca, Arizona in Mohave County. The land ownership...

  4. Lake Powell, Colorado River, Utah and Grand Canyon, Arizona

    NASA Image and Video Library

    1973-06-22

    SL2-04-018 (June 1973) --- A vertical view of the Arizona-Utah border area showing the Colorado River and Grand Canyon photographed from the Skylab 1/2 space station in Earth orbit. This picture was taken by one of the six lenses of the Itek-furnished S190-A Multispectral Photographic Facility Experiment in the Multiple Docking Adapter of the space station. Type S0-356 film was used. The row of white clouds extend north-south over the dark colored Kaibab Plateau. The junction of the Colorado and Little Colorado rivers is in the southwest corner of the picture. The body of water is Lake Powell on the Colorado River upstream from the Grand Canyon. The lone peak at the eastern edge of the photograph south of Colorado River is the 10,416-foot Navajo Mountain. The S190-A experiment is part of the Skylab Earth Resources Experiments Package(EREP). Photo credit: NASA

  5. 33 CFR 165.1171 - Copper Canyon, Lake Havasu, Colorado River-Regulated Navigation Area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Copper Canyon, Lake Havasu... Guard District § 165.1171 Copper Canyon, Lake Havasu, Colorado River—Regulated Navigation Area. (a) Location. The following is a regulated navigation area: (1) In the water area of Copper Canyon, Lake Havasu...

  6. 33 CFR 165.1171 - Copper Canyon, Lake Havasu, Colorado River-Regulated Navigation Area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Copper Canyon, Lake Havasu... Guard District § 165.1171 Copper Canyon, Lake Havasu, Colorado River—Regulated Navigation Area. (a) Location. The following is a regulated navigation area: (1) In the water area of Copper Canyon, Lake Havasu...

  7. Satellite Observations of Drought and Falling Water Storage in the Colorado River Basin and Lake Mead

    NASA Astrophysics Data System (ADS)

    Castle, S.; Famiglietti, J. S.; Reager, J. T.; Thomas, B.

    2012-12-01

    Over the past decade the Western US has experienced extreme drought conditions, which have affected both agricultural and urban areas. An example of water infrastructure being impacted by these droughts is Lake Mead, the largest reservoir in the United States at its full capacity that provides water and energy for several states in the Western US. Once Lake Mead falls below the critical elevation of 1050 feet above sea level, the Hoover Dam, the structure that created Lake Mead by damming flow within the Colorado River, will stop producing energy for Las Vegas. The Gravity Recovery and Climate Experiment (GRACE) satellites, launched in 2002, have proven successful for monitoring changes in water storage over large areas, and give hydrologists a first-ever picture of how total water storage is changing spatially and temporally within large regions. Given the importance of the Colorado River to meet water demands to several neighboring regions, including Southern California, it is vital to understand how water is transported and managed throughout the basin. In this research, we use hydrologic remote sensing to characterize the human and natural water balance of the Colorado River basin and Lake Mead. The research will include quantifying the amount of Colorado River water delivered to Southern California, coupling the GRACE Total Water Storage signal of the Upper and Lower Colorado River with Landsat-TM satellite imagery and areal extent of Lake Mead water storage, and combining these data together to determine the current status of water availability in the Western US. We consider water management and policy changes necessary for sustainable water practices including human water use, hydropower, and ecosystem services in arid regions throughout the Western US.

  8. Trophic classification of selected Colorado lakes

    NASA Technical Reports Server (NTRS)

    Blackwell, R. J.; Boland, D. H. P.

    1979-01-01

    Multispectral scanner data, acquired over several Colorado lakes using LANDSAT-1 and aircraft, were used in conjunction with contact-sensed water quality data to determine the feasibility of assessing lacustrine trophic levels. A trophic state index was developed using contact-sensed data for several trophic indicators. Relationships between the digitally processed multispectral scanner data, several trophic indicators, and the trophic index were examined using a supervised multispectral classification technique and regression techniques. Statistically significant correlations exist between spectral bands, several of the trophic indicators and the trophic state index. Color-coded photomaps were generated which depict the spectral aspects of trophic state.

  9. Phytoplankton dynamics in three Rocky Mountain lakes, Colorado, USA

    USGS Publications Warehouse

    McKnight, Diane M.; Smith, R.L.; Bradbury, J.P.; Baron, Jill S.; Spaulding, S.

    1990-01-01

    In 1984 and 1985 seasonal changes in phytoplankton were studied in a system of three lakes in Loch Vale, Rocky Mountain National Park, Colorado. Three periods were evident: (1) A spring bloom, during snowmelt, of the planktonic diatom Asterionella formosa, (2) a mid-summer period of minimal algal abundance, and (3) a fall bloom of the blue-green alga Oscillatoria limnetica. Seasonal phytoplankton dynamics in these lakes are controlled partially by the rapid flushing rate during snowmelt and the transport of phytoplankton from the highest lake to the lower lakes by the stream, Icy Brook. During snowmelt, the A. formosa population in the most downstream lake has a net rate of increase of 0.34 d-1, which is calculated from the flushing rate and from the A. formosa abundance in the inflow from the upstream lake and in the downstream lake. Measurement of photosynthetic rates at different depths during the three periods confirmed the rapid growth of A. formosa during the spring. The decline in A. formosa after snowmelt may be related to grazing by developing zooplankton populations. The possible importance of the seasonal variations in nitrate concentrations were evaluated in situ enrichment experiments. For A. formosa and O. limnetica populations, growth stimulation resulted from 8- or 16-micromolar amendments of calcium nitrate and sulfuric acid, but the reason for this stimulation could not be determined from these experiments.

  10. Preliminary Geologic Map of the Lake Mead 30' X 60' Quadrangle, Clark County, Nevada, and Mohave County, Arizona

    USGS Publications Warehouse

    Beard, L.S.; Anderson, R.E.; Block, D.L.; Bohannon, R.G.; Brady, R.J.; Castor, S.B.; Duebendorfer, E.M.; Faulds, J.E.; Felger, T.J.; Howard, K.A.; Kuntz, M.A.; Williams, V.S.

    2007-01-01

    Introduction The geologic map of the Lake Mead 30' x 60' quadrangle was completed for the U.S. Geological Survey's Las Vegas Urban Corridor Project and the National Parks Project, National Cooperative Geologic Mapping Program. Lake Mead, which occupies the northern part of the Lake Mead National Recreation Area (LAME), mostly lies within the Lake Mead quadrangle and provides recreation for about nine million visitors annually. The lake was formed by damming of the Colorado River by Hoover Dam in 1939. The recreation area and surrounding Bureau of Land Management lands face increasing public pressure from rapid urban growth in the Las Vegas area to the west. This report provides baseline earth science information that can be used in future studies of hazards, groundwater resources, mineral and aggregate resources, and of soils and vegetation distribution. The preliminary report presents a geologic map and GIS database of the Lake Mead quadrangle and a description and correlation of map units. The final report will include cross-sections and interpretive text. The geology was compiled from many sources, both published and unpublished, including significant new mapping that was conducted specifically for this compilation. Geochronologic data from published sources, as well as preliminary unpublished 40Ar/39Ar ages that were obtained for this report, have been used to refine the ages of formal Tertiary stratigraphic units and define new informal Tertiary sedimentary and volcanic units.

  11. Deposition, Alteration, and Resuspension of Colorado River Delta Sediments, Lake Powell, Utah

    NASA Astrophysics Data System (ADS)

    Kramer, N. M.; Parnell, R.

    2002-12-01

    Current drought conditions in the southwest United States have resulted in lowering water levels in Lake Powell, Utah. Delta sediments forming at the Colorado River inflow for the past 39 years are becoming exposed and reworked as lake levels continue to fall to over 22 meters below full pool level. Fine sediments act as a sink for pollutants by adsorbing contaminants to their surfaces. Reworking these sediments may pose a risk to water quality in the lake. We examine whether burial and time have sufficiently altered fine sediments in the delta and affected materials adsorbed on their surfaces. Fifteen lake cores and six sediment traps were collected from the sediment delta forming at the Colorado River inflow in Lake Powell. This research characterizes fine sediment mineralogy, the composition of exchangeable materials, and organic matter content within delta sediments to determine the type and amount of alteration of these sediments with cycles of burial and resuspension. We hypothesize that as sediments are reworked, organic carbon is degraded and organic nitrogen is released forming ammonium in these reducing conditions. Sediment trap samples will be used to test this hypothesis. Trap samples will be compared to subsamples from sediment cores to determine the amount of alteration of fine sediments. All samples are analyzed for organic carbon, organic nitrogen, ammonium, cation exchange capacity, exchangeable cation composition, and clay mineralogy. Organic carbon and nitrogen are analyzed using a Leco CN analyzer. Ammonium is analyzed using a Lachet ion chromatograph. Clay mineralogy is characterized using a Siemens D500 powder X-ray diffractometer. Cation exchange capacity and exchangeable cations are measured using standard soil chemical techniques. Clay mineral analyses indicate significant spatial and temporal differences in fine sediment entering the Lake Powell delta which complicates the use of a simple deposition/alteration/resuspension model using a

  12. Relative Weight of Brown Trout and Lake Trout in Blue Mesa Reservoir, Colorado

    DTIC Science & Technology

    2012-01-27

    Published data concerning the standard weight in lake trout (Salvelinus namaycush) and brown trout (salmo trutta) have been established. The...standard weights can be used to compute relative weights for data collected in the spring and summer of 2011 for brown trout and lake trout in the Blue Mesa...Reservoir, Colorado. The mean relative weight of a sample of 100 brown trout ranging in length from 260 to 432 mm was 80.01 +/- 0.74, showing that the

  13. Use of Landsat Thematic Mapper images in regional correlation of syntectonic strata, Colorado river extensional corridor, California and Arizona

    NASA Technical Reports Server (NTRS)

    Beratan, K. K.; Blom, R. G.; Crippen, R. E.; Nielson, J. E.

    1990-01-01

    Enhanced Landsat TM images were used in conjunction with field work to investigate the regional correlation of Miocene rocks in the Colorado River extensional corridor of California and Arizona. Based on field investigations, four sequences of sedimentary and volcanic strata could be recognized in the Mohave Mountains (Arizona) and the eastern Whipple Mountains (California), which display significantly different relative volumes and organization of lithologies. The four sequences were also found to have distinctive appearances on the TM image. The recognition criteria derived from field mapping and image interpretation in the Mohave Mountains and Whipple Mountains were applied to an adjacent area in which stratigraphic affinities were less well known. The results of subsequent field work confirmed the stratigraphic and structural relations suggested by the Tm image analysis.

  14. Llano Grande Lake bottom sediments; a chronicle of water-quality changes in the Arroyo Colorado, South Texas, 1989-2001

    USGS Publications Warehouse

    Mahler, Barbara June; Van Metre, Peter C.

    2002-01-01

    The Arroyo Colorado, an ancient channel of the Rio Grande, extends 90 miles from Mission, Tex., to the Laguna Madre. The Arroyo Colorado flows through areas of intense agricultural cultivation and through important habitat for migrating birds and other wildlife, including several wildlife sanctuaries and refuges. The above-tidal segment of the Arroyo Colorado is included in the State of Texas 2000 Clean Water Act 303(d)1 list in part because of elevated concentrations of the hydrophobic legacy pollutants DDE (a DDT breakdown product), chlordane, and toxaphene in fish tissue. This report addresses three questions: Do legacy pollutants (organochlorine compounds, major and trace elements) occur in the Arroyo Colorado at present and at what concentrations?How has the occurrence of selected legacy pollutants in the Arroyo Colorado changed over time?Are current concentrations of legacy pollutants in bottom sediments at levels of concern for the health of aquatic biota?To answer these questions, the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA), collected and analyzed a sediment core from Llano Grande Lake on the Arroyo Colorado (fig. 1). Sediment cores can be used to reconstruct historical trends in concentrations of hydrophobic contaminants (Eisenreich and others, 1989; Van Metre and others, 1997, 2000). The lake is part of the Rio Grande delta drainage system (fig. 1). The lake is 6 miles long and has a maximum width of 600 feet.

  15. Numerical Simulations of Airflows and Tracer Transport in the Southwestern United States.

    NASA Astrophysics Data System (ADS)

    Yamada, Tetsuji

    2000-03-01

    Project MOHAVE (Measurement of Haze and Visual Effects) produced a unique set of tracer data over the southwestern United States. During the summer of 1992, a perfluorocarbon tracer gas was released from the Mohave Power Project (MPP), a large coal-fired facility in southern Nevada. Three-dimensional atmospheric models, the Higher-Order Turbulence Model for Atmospheric Circulation-Random Puff Transport and Diffusion (HOTMAC-RAPTAD), were used to simulate the concentrations of tracer gas that were observed during a portion of the summer intensive period of Project MOHAVE. The study area extended from northwestern Arizona to southern Nevada and included Lake Mead, the Colorado River Valley, the Grand Canyon National Park, and MPP. The computational domain was 368 km in the east-west direction by 252 km in the north-south direction. Rawinsonde and radar wind profiler data were used to provide initial and boundary conditions to HOTMAC simulations. HOTMAC with a horizontal grid spacing of 4 km was able to simulate the diurnal variations of drainage and upslope flows along the Grand Canyon and Colorado River Valley. HOTMAC also captured the diurnal variations of turbulence, which played important roles for the transport and diffusion simulations by RAPTAD. The modeled tracer gas concentrations were compared with observations. The model's performance was evaluated statistically.

  16. Recent vegetation changes along the Colorado River between Glen Canyon Dam and Lake Mead, Arizona

    USGS Publications Warehouse

    Turner, Raymond Marriner; Karpiscak, Martin M.

    1980-01-01

    Vegetation changes in the canyon of the Colorado River between Glen Canyon Dam and Lake Mead were studied by comparing photographs taken prior to completion of Glen Canyon Dam in 1963 with photographs taken afterwards at the same sites. In general, the older pictures show an absence of riparian plants along the banks of the river. The newer photographs of each pair were taken in 1972 through 1976 and reveal an increased density of many plant species. Exotic species, such as saltcedar and camel-thorn, and native riparian plants such as sandbar willow, arrowweed, desert broom and cattail, now form a new riparian community along much of the channel of the Colorado River between Glen Canyon Dam and Lake Mead. The matched photographs also reveal that changes have occurred in the amount of sand and silt deposited along the banks. Detailed maps are presented showing distribution of 25 plant species along the reach of the Colorado River studied. Data showing changes in the hydrologic regime since completion of Glen Canyon Dam are presented. (Kosco-USGS)

  17. 76 FR 61261 - Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ...-AA00 Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ AGENCY: Coast Guard, DHS... Boating Association (IJSBA) World Finals. This temporary safety zone is necessary to provide for the... The International Jet Sports Boating Association is sponsoring the IJSBA World Finals. The event will...

  18. The Colorado River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Moderate-resolution Imaging Spectroradiometer (MODIS) true-color image shows the passage of the Colorado River through several southwestern states. The river begins, in this image, in Utah at the far upper right, where Lake Powell is visible as dark pixels surrounded by the salmon-colored rocks of the Colorado Plateau. The Colorado flows southwest through Glen Canyon, to the Glen Canyon Dam, on the Utah-Arizona border. From there it flows south into Arizona, and then turns sharply west where the Grand Canyon of the Colorado cuts through the mountains. The Colorado flows west to the Arizona-Nevada (upper left) border, where it is dammed again, this time by the Hoover Dam. The dark-colored pixels surrounding the bend in the river are Lake Mead. The river flows south along the border of first Nevada and Arizona and then California and Arizona. The Colorado River, which begins in Rocky Mountain National Park in Colorado, empties into the Gulf of California, seen at the bottom center of this image.

  19. 75 FR 61619 - Safety Zone; IJSBA World Finals, Lower Colorado River, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-06

    ...-AA00 Safety Zone; IJSBA World Finals, Lower Colorado River, Lake Havasu, AZ AGENCY: Coast Guard, DHS... Sports Boating Association (IJSBA) World Finals. This temporary safety zone is necessary to provide for... notice of proposed rulemaking (NPRM) entitled Safety Zone; IJSBA World Finals in the Federal Register (75...

  20. 75 FR 43551 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Mohave County Wind...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-26

    ... Dam. The project will consist of up to 335 wind turbine generators (WTGs). Construction may consist of... County Wind Farm Project, Mohave County, AZ AGENCY: Bureau of Land Management, Interior. ACTION: Notice....gov/az/st/en/prog/energy/wind/mohave.html . In order to be included in the Draft EIS, all comments...

  1. Crystalline rocks of the Strawberry Lake area, Front Range, Colorado

    USGS Publications Warehouse

    Young, Edward J.

    1991-01-01

    This report is a petrographic and geochemical study of the bedrock and a petrologic discussion based on felsic-mafic and silica-saturation ratios of the Strawberry Lake area. This volume is published as chapters A and B. These chapters are not available separatelyThe Strawberry lake area lies between the Continental Divide and Granby, Colorado, just north of Tabernash. It is underlain by Proterozoic rocks composed of biotite gneiss and two plutons-Boulder Creek Granodiorite of the Routt Plutonic Suite and Silver Plume Granite of the Berthoud Plutonic Suite. Relict enclaves of biotite gneiss are not uncommon in the Boulder Creek Granodiorite, in the Silver Plume Granite, and in the granitic enclaves in the biotite gneiss. Granitic and mafic enclaves in the Boulder Creek Granodiorite, granitic enclaves in the Silver Plume Granite and in the biotite gneiss, and a Tertiary andesite porphyry dike complete the rock types.

  2. Paleogeographic implications of Late Miocene lacustrine and nonmarine evaporite deposits in the Lake Mead region: Immediate precursors to the Colorado River

    USGS Publications Warehouse

    Faulds, James E.; Schreiber, Charlotte; Langenheim, Victoria; Hinz, Nicholas H.; Shaw, Tom; Heizler, Matthew T.; Perkins, Michael E; El Tabakh, Mohammed; Kunk, Michael J.

    2016-01-01

    Thick late Miocene nonmarine evaporite (mainly halite and gypsum) and related lacustrine limestone deposits compose the upper basin fill in half grabens within the Lake Mead region of the Basin and Range Province directly west of the Colorado Plateau in southern Nevada and northwestern Arizona. Regional relations and geochronologic data indicate that these deposits are late synextensional to postextensional (ca. 12–5 Ma), with major extension bracketed between ca. 16 and 9 Ma and the abrupt western margin of the Colorado Plateau established by ca. 9 Ma. Significant accommodation space in the half grabens allowed for deposition of late Miocene lacustrine and evaporite sediments. Concurrently, waning extension promoted integration of initially isolated basins, progressive enlargement of drainage nets, and development of broad, low gradient plains and shallow water bodies with extensive clastic, carbonate, and/or evaporite sedimentation. The continued subsidence of basins under restricted conditions also allowed for the preservation of particularly thick, localized evaporite sequences prior to development of the through-going Colorado River.The spatial and temporal patterns of deposition indicate increasing amounts of freshwater input during the late Miocene (ca. 12–6 Ma) immediately preceding arrival of the Colorado River between ca. 5.6 and 4.9 Ma. In axial basins along and proximal to the present course of the Colorado River, evaporite deposition (mainly gypsum) transitioned to lacustrine limestone progressively from east to west, beginning ca. 12–11 Ma in the Grand Wash Trough in the east and shortly after ca. 5.6 Ma in the western Lake Mead region. In several satellite basins to both the north and south of the axial basins, evaporite deposition was more extensive, with thick halite (>200 m to 2.5 km thick) accumulating in the Hualapai, Overton Arm, and northern Detrital basins. Gravity and magnetic lows suggest that thick halite may also lie within the

  3. Environmental characteristics and benthic invertebrate assemblages in Colorado mountain lakes

    USGS Publications Warehouse

    LaFrancois, B.M.; Carlisle, D.M.; Nydick, K.R.; Johnson, B.M.; Baron, Jill S.

    2003-01-01

    Twenty-two high-elevation lakes (>3000 m) in Rocky Mountain National Park and Indian Peaks Wilderness Area, Colorado, were surveyed during summer 1998 to explore relationships among benthic invertebrates, water chemistry (particularly nitrate concentrations), and other environmental variables. Water samples were collected from the deepest portion of each lake and analyzed for ions and other water chemistry parameters. Benthic invertebrates were collected from the littoral zone using both a sweep net and Hess sampler. Physical and geographical measurements were derived from maps. Relationships among benthic invertebrate assemblages and environmental variables were examined using canonical correspondence analysis, and the importance of sampling methodology and taxonomie resolution on these relationships was evaluated. Choice of sampling methodology strongly influenced the outcome of statistical analyses, whereas taxonomie resolution did not. Presence/absence of benthic invertebrate taxa among the study lakes was best explained by elevation and presence of fish. Relative abundance and density of benthic invertebrate taxa were more strongly influenced by sampling date and water chemistry. Nitrate (NO₃⁻) concentration, potentially on the rise due to regional nitrogen deposition, was unrelated to benthic invertebrate distribution regardless of sampling method or taxonomie resolution.

  4. Viability of male gametes in common carp (Cyprinus carpio) along the Lower Colorado River from the Cibola National Wildlife Refuge (NWR), Havasu NWR, and Lake Mohave of Lake Mead National Recreation Area

    USGS Publications Warehouse

    Jenkins, Jill A.; Goodbred, Steven L.

    2005-01-01

    To contribute to an investigation on possible endocrine impacts in three sites along the lower Colorado River in Arizona, especially in male fishes, this study addressed the null hypothesis that aquatic species in southern sites did not exhibit evidence of endocrine disruption as compared with those in nonimpacted sites. The results presented are intended to provide managers with science-based information and interpretations about the reproductive condition of biota in their habitat along the lower Colorado River to minimize any potential adverse effects to trust fish and wildlife resources and to identify water resources of acceptable quality. In particular, these data can inform decision making about wastewater discharges into the Colorado River that directly supplies water to Arizona refuges located along the river. These data are integral to the USFWS proposal entitled 'AZ - Endocrine Disruption in Razorback Sucker and Common Carp on National Wildlife Refuges along the Lower Colorado River' that was proposed to assess evidence of endocrine disruption in carp and razorback suckers downstream of Hoover Dam.

  5. A Feasibility Study for Inclusion of Mohave County Community College in the State Community College System of Arizona.

    ERIC Educational Resources Information Center

    Northern Arizona Univ., Flagstaff. Educational Resources Management Center.

    The major purpose of this study was to accumulate and organize pertinent information relative to the future status and goals of Mohave County Community College. The major objectives of the survey were to: (1) describe the growth and development of the Mohave County Community College, (2) describe the present educational program of the college, (3)…

  6. Use of chemistry and stable sulfur isotopes to determine sources of trends in sulfate of Colorado lakes

    USGS Publications Warehouse

    Turk, J.T.; Campbell, D.H.; Spahr, N.E.

    1993-01-01

    The chemistry of lakes in the Mt. Zukel Wilderness Area (MZWA) and the Weminuche Wilderness Area (WWA) of Colorado has been monitored since 1985. The initial results indicate that changes have occurred in the chemistry of some lakes in both areas. Increased concentration of sulfate in lakes may be related to increased atmospheric deposition of sulfate or to changes of sulfate released by weathering and to changing dilution of sulfate by snowmelt. Stable S isotopes seem to be capable of separating the fraction of change in sulfate that is related to atmospheric and watershed sources. Because of the short period of record, it is not possible to determine whether the changes are part of a long-term trend or are merely natural fluctuations about some baseline.The chemistry of lakes in th Mt. Zirkel Wilderness Area (MZWA) and Weminche Wilderness Area (WWA) of Colorado has been monitored since 1985. The initial results indicate that changes have occured in the chemistry of some lakes in both areas. Increased concentration of sulfate in lakes may be related to increased atmospheric deposition of sulfateor to changes of sulfate released by weathering and to changing dilution of sulfate by snowmelt. Stable S isotopes seem to be capable of separating the fraction of change in sulfate that is related to atmospheric and watershed sources. Because of the short period of record, it is not possible to determine whether the changes are part of long-term or are merely natural fluctuations about some baseline.

  7. Response of lake chemistry to changes in atmospheric deposition and climate in three high-elevation wilderness areas of Colorado

    USGS Publications Warehouse

    Mast, M. Alisa; Turk, John T.; Clow, David W.; Campbell, Donald D.

    2011-01-01

    Trends in precipitation chemistry and hydrologic and climatic data were examined as drivers of long-term changes in the chemical composition of high-elevation lakes in three wilderness areas in Colorado during 1985-2008. Sulfate concentrations in precipitation decreased at a rate of -0.15 to -0.55 μeq/l/year at 10 high-elevation National Atmospheric Deposition Program stations in the state during 1987-2008 reflecting regional reductions in SO2 emissions. In lakes where sulfate is primarily derived from atmospheric inputs, sulfate concentrations also decreased although the rates generally were less, ranging from -0.12 to -0.27 μeq/l/year. The similarity in timing and sulfur isotopic data support the hypothesis that decreases in atmospheric deposition are driving the response of high-elevation lakes in some areas of the state. By contrast, in lakes where sulfate is derived primarily from watershed weathering sources, sulfate concentrations showed sharp increases during 1985-2008. Analysis of long-term climate records indicates that annual air temperatures have increased between 0.45 and 0.93°C per decade throughout most mountainous areas of Colorado, suggesting climate as a factor. Isotopic data reveal that sulfate in these lakes is largely derived from pyrite, which may indicate climate warming is preferentially affecting the rate of pyrite weathering.

  8. Response of lake chemistry to changes in atmospheric deposition and climate in three high-elevation wilderness areas of Colorado

    USGS Publications Warehouse

    Mast, M.A.; Turk, J.T.; Clow, D.W.; Campbell, D.H.

    2011-01-01

    Trends in precipitation chemistry and hydrologic and climatic data were examined as drivers of long-term changes in the chemical composition of high-elevation lakes in three wilderness areas in Colorado during 1985-2008. Sulfate concentrations in precipitation decreased at a rate of -0.15 to -0.55 ??eq/l/year at 10 high-elevation National Atmospheric Deposition Program stations in the state during 1987-2008 reflecting regional reductions in SO2 emissions. In lakes where sulfate is primarily derived from atmospheric inputs, sulfate concentrations also decreased although the rates generally were less, ranging from -0.12 to -0.27 ??eq/l/year. The similarity in timing and sulfur isotopic data support the hypothesis that decreases in atmospheric deposition are driving the response of high-elevation lakes in some areas of the state. By contrast, in lakes where sulfate is derived primarily from watershed weathering sources, sulfate concentrations showed sharp increases during 1985-2008. Analysis of long-term climate records indicates that annual air temperatures have increased between 0.45 and 0.93??C per decade throughout most mountainous areas of Colorado, suggesting climate as a factor. Isotopic data reveal that sulfate in these lakes is largely derived from pyrite, which may indicate climate warming is preferentially affecting the rate of pyrite weathering. ?? 2010 US Government.

  9. 33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Marshall Ford Dam and Reservoir... Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. The Secretary of the... and Reservoir in the interest of flood control as follows: (a) Water Control Plan—(1) General...

  10. 33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Marshall Ford Dam and Reservoir... Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. The Secretary of the... and Reservoir in the interest of flood control as follows: (a) Water Control Plan—(1) General...

  11. Transport of pollutants from cow feedlots in eastern Colorado into Rocky Mountain alpine lakes

    NASA Astrophysics Data System (ADS)

    Pina, A.; Denning, S.; Schumacher, R. S.

    2012-12-01

    Concentrated Animal Feeding Operations (CAFOs), also called factory farms, are known for raising tens of millions head of livestock including cows (beef and dairy), swine, and poultry. With as many as 250 head of cattle per acre, a United States Department of Agriculture's (USDA) Agricultural Research Service (ARS) report showed beef cattle from CAFOs in the United States produce as much as 24.1 million tons of manure annually. Gases released from cow manure include methane (CH4), nitrous oxide (N2O), hydrogen sulfide (H2S), and ammonia (NH3). During boreal summers Colorado experiences fewer synoptic weather systems, allowing the diurnal cycle to exert greater control of meteorological events along the mountain-plains interface. Anabatic, or upslope winds induced by the diurnal cycle, contribute largely to the transport of gases and particulates from feedlots in eastern Colorado into the Rocky Mountains, presenting a potential harm to natural alpine ecosystems. This study focuses on locating the source of transport of gases from feedlots along the eastern Front Range of Colorado into alpine lakes of the Rocky Mountains. Source regions are approximated using backward time simulation of a Lagrangian Transport model.

  12. Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of Colorado Front Range (USA)

    USGS Publications Warehouse

    Wolfe, A.P.; Baron, Jill S.; Cornett, R.J.

    2001-01-01

    Recent sediments from two alpine lakes (> 3300 m asl) in the Colorado Front Range (USA) register marked and near-synchronous changes that are believed to represent ecological responses to enhanced atmospheric deposition of fixed nitrogen from anthropogenic sources. Directional shifts in sediment proxies include greater representations of mesotrophic diatoms and increasingly depleted δ15N values. These trends are particularly pronounced since ~ 1950, and appear to chronicle lake responses to excess N derived from agricultural and industrial sources to the east. The rate and magnitude of recent ecological changes far exceed the context of natural variability, as inferred from comparative analyses of a long core capturingthe entire 14,000-year postglacial history of one of the lakes. Nitrogen deposition to these seemingly pristine natural areas has resulted in subtle but detectable limnological changes that likely represent the beginning of a stronger response to nitrogen enrichment.

  13. Characterization of selected radionuclides in sediment and surface water in Standley Lake, Great Western Reservoir, and Mower Reservoir, Jefferson County, Colorado, 1992

    USGS Publications Warehouse

    Clow, D.W.; Johncox, D.A.

    1995-01-01

    Lake sediment and surface water from Standley Lake, Great Western Reservoir, and Mower Reservoir, near Denver, Colorado, were sampled and analyzed for selected radionuclides during August through October, 1992. Sample concentrations were summarized and compared to results from a study conducted in 1983-84. Median plutonium-239,240 (239,240Pu) concentrations in lake-sediment grab samples from Standley Lake, Great Western Reservoir, and Mower Reservoir were 0.037, 0.105, and 0.351 picocuries per gram (pCi/g). The maximum concen- tration of 239,240Pu dissolved in lake water was 0.009 picocuries per liter, substantially below limits suggested by the Colorado Department of Health and the Environment. Dissolved concentrations of gross alpha and uranium isotopes were below National Drinking Water Standards in all water samples. There was no statistically significant difference between 239,240Pu concentration in lake-sediment grab samples collected from Standley Lake in 1983-84 and in 1992; however, there was a small, but statistically significant, difference at Great Western Reservoir (p<0.05). In 1992 at Great Western Reservoir, median 239,240Pu concentrations were 0.040 pCi/g lower than in 1983-84. There was a small, but statistically significant (p<0.05) difference in 239,240Pu concentrations in lake- bottom-sediment cores collected in 1983-84 and in 1992. Measured concentrations tended to be higher in 1983-84 than in 1992. The differences were greatest at concentrations above 1.5 pCi/g; in those samples concentrations were 10 to 30% higher in 1983-84 than in 1992.

  14. Impacts on water quality and biota from natural acid rock drainage in Colorado's Lake Creek watershed

    USGS Publications Warehouse

    Bird, D.A.; Sares, Matthew A.; Policky, Greg A.; Schmidt, Travis S.; Church, Stan E.

    2006-01-01

    Colorado's Lake Creek watershed hosts natural acid rock drainage that significantly impacts surface water, streambed sediment, and aquatic life. The source of the ARD is a group of iron-rich springs that emerge from intensely hydrothermally altered, unexploited, low-grade porphyry copper mineralization in the Grizzly Peak Caldera. Source water chemistry includes pH of 2.5 and dissolved metal concentrations of up to 277 mg/L aluminum, 498 mg/L iron, and 10 mg/L copper. From the hydrothermally altered area downstream for 27 kilometers to Twin Lakes Reservoir, metal concentrations in streambed sediment are elevated and the watershed experiences locally severe adverse impacts to aquatic life due to the acidic, metal-laden water. The water and sediment quality of Twin Lakes Reservoir is sufficiently improved that the reservoir supports a trout fishery, and remnants of upstream ARD are negligible.

  15. Silver concentrations and selected hydrologic data in the Upper Colorado River basin, 1991-92

    USGS Publications Warehouse

    Johncox, D.A.

    1993-01-01

    The U.S. Geological Survey, in cooperation with the Colorado River Water Conservation District and the Northern Colorado Water Conservancy District, collected water and sediment samples in May and September 1991 and 1992 from nine stream-sampling sites and three lake-sampling sites within the Upper Colorado River Basin upstream from Kremmling, Colorado. Data were collected to determine the present (1992) conditions of the Upper Colorado River Basin regarding silver concentrations in the water and sediment. Lake-water and stream-water samples were analyzed for concentrations of total recoverable silver, dissolved silver, and suspended solids. Lake- and stream-bottom material was analyzed for concentrations of total recoverable silver. Additional data collected were streamflow, specific conductance, pH, and water temperature. Transparency (Secchi-disk measurements) also was measured in the lakes.

  16. 75 FR 20920 - Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ...-AA00 Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ AGENCY: Coast Guard, DHS. ACTION: Temporary... of Lake Havasu on the Colorado River in Lake Havasu City, Arizona for the Lake Havasu Grand Prix... established in support of the Lake Havasu Grand Prix, a marine event that includes participating vessels...

  17. Temporal coherence of two alpine lake basins of the Colorado Front Range, USA

    USGS Publications Warehouse

    Baron, Jill S.; Caine, N.

    2000-01-01

    1. Knowledge of synchrony in trends is important to determining regional responses of lakes to disturbances such as atmospheric deposition and climate change. We explored the temporal coherence of physical and chemical characteristics of two series of mostly alpine lakes in nearby basins of the Colorado Rocky Mountains. Using year-to-year variation over a 10-year period, we asked whether lakes more similar in exposure to the atmosphere be-haved more similarly than those with greater influence of catchment or in-lake processes.2. The Green Lakes Valley and Loch Vale Watershed are steeply incised basins with strong altitudinal gradients. There are glaciers at the heads of each catchment. The eight lakes studied are small, shallow and typically ice-covered for more than half the year. Snowmelt is the dominant hydrological event each year, flushing about 70% of the annual discharge from each lake between April and mid-July. The lakes do not thermally stratify during the period of open water. Data from these lakes included surface water temper-ature, sulphate, nitrate, calcium, silica, bicarbonate alkalinity and conductivity.3. Coherence was estimated by Pearson's correlation coefficient between lake pairs for each of the different variables. Despite close geographical proximity, there was not a strong direct signal from climatic or atmospheric conditions across all lakes in the study. Individual lake characteristics overwhelmed regional responses. Temporal coherence was higher for lakes within each basin than between basins and was highest for nearest neighbours.4. Among the Green Lakes, conductivity, alkalinity and temperature were temporally coherent, suggesting that these lakes were sensitive to climate fluctuations. Water tem-perature is indicative of air temperature, and conductivity and alkalinity concentrations are indicative of dilution from the amount of precipitation flushed through by snowmelt.5. In Loch Vale, calcium, conductivity, nitrate, sulphate and

  18. Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of the Colorado Front Range (USA)

    USGS Publications Warehouse

    Wolfe, A.P.; Baron, Jill S.; Cornett, R.J.

    2001-01-01

    Recent sediments from two alpine lakes (> 3300 m asl) in the Colorado Front Range (USA) register marked and near-synchronous changes that are believed to represent ecological responses to enhanced atmospheric deposition of fixed nitrogen from anthropogenic sources. Directional shifts in sediment proxies include greater representations of mesotrophic diatoms and increasingly depleted ??15N values. These trends are particularly pronounced since ??? 1950, and appear to chronicle lake responses to excess N derived from agricultural and industrial sources to the east. The rate and magnitude of recent ecological changes far exceed the context of natural variability, as inferred from comparative analyses of a long core capturing the entire 14,000-year postglacial history of one of the lakes. Nitrogen deposition to these seemingly pristine natural areas has resulted in subtle but detectable limnological changes that likely represent the beginning of a stronger response to nitrogen enrichment.

  19. Lake Powell

    NASA Image and Video Library

    2007-09-20

    The white ring around Lake Powell tells the story. The surface is down 98 feet. This is critical, because Powell, Lake Mead, and other lakes along the Colorado River provide water for millions of people in five states. We are in the eighth year of a drought on the Colorado River. This year was the driest year ever reported in Southern California, and there is a severe drought in Northern California, down to less than 30-percent of snow pack. This ASTER image of part of Lake Powell was acquired in 2001. The gray area depicts the shrunken, reduced 2007 lake extent compared to the extended, larger black area in 2001. The image covers an area of 24 x 30 km, and is centered near 37.1 degrees north latitude, 111.3 degrees west longitude. This image from NASA Terra satellite. http://photojournal.jpl.nasa.gov/catalog/PIA10614

  20. Characterization of water quality in Government Highline Canal at Camp 7 Diversion and Highline Lake, Mesa County, Colorado, July 2000 through September 2003

    USGS Publications Warehouse

    Ortiz, Roderick F.

    2004-01-01

    The U.S. Geological Survey, in cooperation with the Colorado Division of Parks and Recreation, collected and analyzed water-quality data for the Government Highline Canal and Highline Lake from July 2000 through September 2003. Implementation of modernization strategies for the canal, which supplies most of the water to the lake, would decrease the amount of water spilled to Highline Lake from August through October. A reduction in spill water into Highline Lake could adversely affect the recreational uses of the lake. To address this concern and to characterize the water quality in the Government Highline Canal and Highline Lake, the U.S. Geological Survey conducted a study to evaluate limnological conditions prior to implementation of the modernization strategies. This report characterizes the water quality of inflow from the Government Canal and in Highline Lake prior to implementation of modernization strategies in the Government Canal. Flow entering the lake from the Government Canal was characterized using field properties and available chemical, sediment, and bacteria concentrations. Data collected at Highline Lake were used to characterize the seasonal stratification patterns, water-quality chemistry, bacteria populations, and phytoplankton community structure in the lake. Data used for this report were collected at one inflow site to the lake and four sites in Highline Lake. Highline Lake is a mesotrophic/eutrophic lake that has dimictic thermal stratification patterns. Samples collected in the photic zone indicated that there was little physical, chemical, or biological variability at this depth at any of the sampled sites in Highline Lake. Strong thermal and dissolved-oxygen stratification patterns were observed during summer. Dissolved-oxygen concentrations of less than 1 milligram per liter were observed during the summer. Ammonia likely was released from the bottom sediments of Highline Lake. The limiting nutrient in Highline Lake could be nitrogen or

  1. Nahcolite and halite deposition through time during the saline mineral phase of Eocene Lake Uinta, Piceance Basin, western Colorado

    USGS Publications Warehouse

    Johnson, Ronald C.; Brownfield, Michael E.

    2013-01-01

    Halite and the sodium bicarbonate mineral nahcolite were deposited during the saline phase of Eocene Lake Uinta in the Piceance Basin, western Colorado. Variations in the area of saline mineral deposition through time were interpreted from studies of core and outcrop. Saline minerals were extensively leached by groundwater, so the original extent of saline deposition was estimated from the distribution of empty vugs and collapse breccias. Vugs and breccias strongly influence groundwater movement, so determining where leaching has occurred is an important consideration for in-situ oil shale extraction methods currently being developed. Lake Uinta formed when two smaller fresh water lakes, one in the Uinta Basin of eastern Utah and the other in the Piceance Basin of western Colorado, expanded and coalesced across the Douglas Creek arch, an area of comparatively low subsidence rates. Salinity increased shortly after this expansion, but saline mineral deposition did not begin until later, after a period of prolonged infilling created broad lake-margin shelves and a comparatively small deep central lake area. These shelves probably played a critical role in brine evolution. A progression from disseminated nahcolite and nahcolite aggregates to bedded nahcolite and ultimately to bedded nahcolite and halite was deposited in this deep lake area during the early stages of saline deposition along with rich oil shale that commonly shows signs of slumping and lateral transport. The area of saline mineral and rich oil shale deposition subsequently expanded, in part due to infilling of the compact deep area, and in part because of an increase in water flow into Lake Uinta, possibly due to outflow from Lake Gosiute to the north. Finally, as Lake Uinta in the Piceance Basin was progressively filled from north to south by volcano-clastic sediment, the saline depocenter was pushed progressively southward, eventually covering much of the areas that had previously been marginal shelves

  2. Landscape patterns of montane forest age structure relative to fire history at Cheesman Lake in the Colorado Front Range

    Treesearch

    Laurie S. Huckaby; Merrill R. Kaufmann; Jason M. Stoker; Paula J. Fornwalt

    2001-01-01

    Lack of Euro-American disturbance, except fire suppression, has preserved the patterns of forest structure that resulted from the presettlement disturbance regime in a ponderosa pine/Douglas-fir landscape at Cheesman Lake in the Colorado Front Range. A mixed-severity fire regime and variable timing of tree recruitment created a heterogeneous forest age structure with...

  3. Lake Powell

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The white ring around Lake Powell tells the story. The surface is down 98 feet. This is critical, because Powell, Lake Mead, and other lakes along the Colorado River provide water for millions of people in five states. We are in the eighth year of a drought on the Colorado River. This year was the driest year ever reported in Southern California, and there is a severe drought in Northern California, down to less than 30-percent of snow pack. This ASTER image of part of Lake Powell was acquired in 2001. The gray area depicts the shrunken, reduced 2007 lake extent compared to the extended, larger black area in 2001.

    The image covers an area of 24 x 30 km, and is centered near 37.1 degrees north latitude, 111.3 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  4. Cheesman Lake-a historical ponderosa pine landscape guiding restoration in the South Platte Watershed of the Colorado Front Range

    Treesearch

    Merrill R. Kaufmann; Paula J. Fornwalt; Laurie S. Huckaby; Jason M. Stoker

    2001-01-01

    An unlogged and ungrazed ponderosa pine/Douglas-fir landscape in the Colorado Front Range provides critical information for restoring forests in the South Platte watershed. A frame-based model was used to describe the relationship among the four primary patch conditions in the 35-km2 Cheesman Lake landscape: (1) openings, (2) ponderosa pine forest, (3) ponderosa pine/...

  5. Geologic map of the Fredonia 30' x 60' quadrangle, Mohave and Coconino counties, northern Arizona

    USGS Publications Warehouse

    Billingsley, George H.; Priest, Susan S.; Felger, Tracey J.

    2008-01-01

    This geologic map is the result of a cooperative effort of the U.S. Geological Survey, the National Park Service, the U.S. Forest Service, and the Bureau of Land Management (BLM) and the Kaibab-Paiute Tribe to provide a regional geologic database for resource management officials of all government and agencies, city municipalities, private enterprises, and individuals of this part of the Arizona Strip. The Arizona Strip is part of northwestern Arizona north of the Colorado River and bounded by the States of Nevada and Utah. Field work on the Kaibab-Paiute Indian Reservation was conducted from 2002 to 2005 with permission from the Kaibab-Paiute Tribal Government of that administration and permission was granted to publish a geologic map of 4 quadrangles online (Billingsley and others, 2004). The Kaibab-Paiute Tribal government of 2006 to 2008 requested that all geologic information within the Kaibab-Paiute Indian Reservation not be published as part of the Fredonia 30' x 60' quadrangle (this publication). For further information, contact the Kaibab-Paiute Tribal government at HC 65 Box 2, Fredonia, Arizona, 86022, telephone # (928) 643-7245. Visitors to the Kaibab-Paiute Indian Reservation are required to obtain a permit and permission for access from the Tribal Offices at the junction of State Highway 389 and the paved road leading to Pipe Spring National Monument. The Fredonia 30' x 60' quadrangle encompasses approximately 5,018 km2 (1,960 mi2) within Mohave and Coconino Counties, northern Arizona and is bounded by longitude 112 deg to 113 deg W., and latitude 36 deg 30' to 37 deg N. The map area lies within the southern Colorado Plateaus geologic province (herein Colorado Plateau). The map area is locally subdivided into seven physiographic parts: the Grand Canyon (Kanab Canyon and its tributaries), Kanab Plateau, Uinkaret Plateau, Kaibab Plateau, Paria Plateau, House Rock Valley, and Moccasin Mountains as defined by Billingsley and others, 1997, (fig. 1

  6. Seasonal inorganic nitrogen release in alpine lakes on the Colorado western slope

    USGS Publications Warehouse

    Inyan, B.I.; Williams, M.W.; Tonnessen, K.; Turk, J.T.; Campbell, D.H.

    1998-01-01

    In the Rocky Mountains, the association of increases in acidic deposition with increased atmospheric loading of sulfate and direct changes in surface water chemistry has been well established. The importance, though, of increased nitrogen (N) deposition in the episodic acidification of alpine lakes and N saturation in alpine ecosystems is only beginning to be documented. In alpine areas of the Colorado Front Range, modest loadings of N in deposition have been associated with leakage of N to surface waters. On the Colorado western slope, however, no leakage of N to surface waters has been reported. A 1995 study that included early season under-ice water samples that were not available in earlier studies showed that there is, in fact, N leakage to surface waters in some western slope basins. Under-ice nitrate (NO3-) concentrations were as high as 10.5 ??q L-1, and only decreased to detection limits in September. Landscape type appears to be important in leakage of N to surface waters, which is associated with basins having steep slopes, thin soils, and large amounts of exposed bedrock. NO3- leakage compounds the existing sensitivity to episodic acidification from low acid neutralizing capacity (ANC), which is less than 40 ??eq L-1 in those basins.

  7. 78 FR 17869 - Safety Zone; Desert Storm Shootout; Lake Havasu, Lake Havasu City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-25

    ...-AA00 Safety Zone; Desert Storm Shootout; Lake Havasu, Lake Havasu City, AZ AGENCY: Coast Guard, DHS... navigable waters of the Colorado River in Lake Havasu, Lake Havasu City, Arizona in support of the Desert... Coast Guard to establish safety zones (33 U.S.C 1221 et seq.). Lake Racer LLC is sponsoring the Desert...

  8. Physical Controls on Delta Formation and Carbon Storage in Mountain Lakes

    NASA Astrophysics Data System (ADS)

    Scott, D.; Wohl, E.

    2014-12-01

    Carbon acts as a component in greenhouse gases that regulate global climate. It is imperative to understand the transport and storage of carbon in order to understand and manage climate change. We examine terrestrial carbon storage in mountain lake deltas as a way of furthering our understanding of the terrestrial carbon sink, which is a poorly understood but significant contributor to the global carbon cycle. We examined subalpine lake deltas in the Washington Cascade Range and Colorado Front Range to test the following hypotheses: 1) The size of the deltaic carbon sink is strongly correlated with incision at the outlet of the lake and the topography of the basin. 2) Areas of high exhumation rates will have smaller and fewer deltas because a high exhumation rate should lead to more confined basins and more colluvium available to dam lake outlets, preventing lake level drop and corresponding delta formation. 3) High-energy deltas will transport more carbon to lakes, avoiding the deltaic carbon sink. At 27 lakes, we surveyed mountain lake deltas and took sediment samples, surveyed lake outlets in the field, and measured lake valley confinement in GIS to test hypotheses 1 and 3. Across the Snoqualmie and Skykomish watersheds in the Washington Cascades and the Colorado Front Range, we took a census of the number of natural lakes and the proportion of those lakes with deltas to test hypothesis 2. Preliminary results indicate that the Washington Cascades (high exhumation rate) have a higher density of lakes, but fewer deltas, than the Colorado Front Range (low exhumation rate). We also suspect that deltas in the Washington Cascades will have a lower carbon content than the Colorado Front Range due to generally higher energy levels on deltas. Finally, we found a substantial difference in the geomorphology and sediment type between beaver-affected and non-beaver-affected lakes in the Colorado Front Range.

  9. Compound-specific stable isotopes of organic compounds from lake sediments track recent environmental changes in an alpine ecosystem, Rocky Mountain National Park, Colorado

    USGS Publications Warehouse

    Enders, S.K.; Pagani, M.; Pantoja, S.; Baron, Jill S.; Wolfe, A.P.; Pedentchouk, N.; Nunez, L.

    2008-01-01

    Compound-specific nitrogen, carbon, and hydrogen isotope records from sediments of Sky Pond, an alpine lake in Rocky Mountain National Park (Colorado, United States of America), were used to evaluate factors contributing to changes in diatom assemblages and bulk organic nitrogen isotope records identified in lake sediments across Colorado, Wyoming, and southern Montana. Nitrogen isotopic records of purified algal chlorins indicate a substantial shift in nitrogen cycling in the region over the past ???60 yr. Temporal changes in the growth characteristics of algae, captured in carbon isotope records in and around Sky Pond, as well as a -60??? excursion in the hydrogen isotope composition of algal-derived palmitic acid, are coincident with changes in nitrogen cycling. The confluence of these trends is attributed to an increase in biologically available nitrogenous compounds caused by an expansion of anthropogenic influences and temporal changes in catchment hydrology and nutrient delivery associated with meltwater dynamics. ?? 2008, by the American Society of Limnology and Oceanography, Inc.

  10. Fish Lake, Utah - a promising long core site straddling the Great Basin to Colorado Plateau transition zone

    NASA Astrophysics Data System (ADS)

    Marchetti, D. W.; Abbott, M. B.; Bailey, C.; Wenrich, E.; Stoner, J. S.; Larsen, D. J.; Finkenbinder, M. S.; Anderson, L.; Brunelle, A.; Carter, V.; Power, M. J.; Hatfield, R. G.; Reilly, B.; Harris, M. S.; Grimm, E. C.; Donovan, J.

    2015-12-01

    Fish Lake (~7x1.5 km and 2696 m asl) is located on the Fish Lake Plateau in central Utah. The Lake occupies a NE-striking tectonic graben; one of a suite of grabens on the Plateau that cut 21-26 Ma volcanic rocks. The lake outflows via Lake Creek to the NE where it joins Sevenmile Creek to become the Fremont River, a tributary to the Colorado River. A bathymetric survey reveals a mean depth of 27 m and a max depth of 37.2 m. The lake bottom slopes from NW to SE with the deepest part near the SE wall, matching the topographic expression of the graben. Nearby Fish Lake Hightop (3545 m) was glaciated with an ice field and outlet glaciers. Exposure ages indicate moraine deposition during Pinedale (15-23 ka) and Bull Lake (130-150 ka) times. One outlet glacier at Pelican Canyon deposited moraines and outwash into the lake but the main basin of the lake was never glaciated. Gravity measurements indicate that lake sediments thicken toward the SE side of the lake and the thickest sediment package is modeled to be between 210 and 240 m. In Feb 2014 we collected cores from Fish Lake using a 9-cm diameter UWITECH coring system in 30.5 m of water. A composite 11.2-m-long core was constructed from overlapping 2 m drives that were taken in triplicate to ensure total recovery and good preservation. Twelve 14C ages and 3 tephra layers of known age define the age model. The oldest 14C age of 32.3±4.2 cal ka BP was taken from 10.6 m. Core lithology, CT scans, and magnetic susceptibility (ms) reveal three sediment packages: an organic-rich, low ms Holocene to post-glacial section, a fine-grained, minerogenic glacial section with high ms, and a short section of inferred pre-LGM sediment with intermediate composition. Extrapolating the age model to the maximum estimated sediment thicknesses suggest sediments may be older than 500-700 ka. Thus Fish Lake is an ideal candidate for long core retrieval as it likely contains paleoclimatic records extending over multiple glacial cycles.

  11. 78 FR 29151 - Notice of Availability of the Final Environmental Impact Statement for the Proposed Mohave County...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-17

    .../energy/wind/mohave.html . The Project is proposed to consist of up to 283 turbines, access roads, and... be supplemented with internal access/service roads to each wind turbine. Proposed ancillary... all action alternatives, Project features within the wind-farm site would include turbines aligned...

  12. Lake Mead, NV

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead.

  13. A late Miocene-early Pliocene chain of lakes fed by the Colorado River: Evidence from Sr, C, and O isotopes of the Bouse Formation and related units between Grand Canyon and the Gulf of California

    USGS Publications Warehouse

    Roskowski, J.A.; Patchett, P.J.; Spencer, J.E.; Pearthree, P.A.; Dettman, D.L.; Faulds, J.E.; Reynolds, A.C.

    2010-01-01

    We report strontium isotopic results for the late Miocene Hualapai Limestone of the Lake Mead area (Arizona-Nevada) and the latest Miocene to early Pliocene Bouse Formation and related units of the lower Colorado River trough (Arizona-California-Nevada), together with parallel oxygen and carbon isotopic analyses of Bouse samples, to constrain the lake-overflow model for integration of the Colorado River. Sr iso topic analyses on the basal 1-5 cm of marl, in particular along a transect over a range of altitude in the lowest-altitude basin that contains freshwater, brackish, and marine fossils, document the 87Sr/86Sr of first-arriving Bouse waters. Results reinforce the similarity between the 87Sr/86Sr of Bouse Formation carbonates and present-day Colorado River water, and the systematic distinction of these values from Neogene marine Sr. Basal Bouse samples show that 87Sr/86Sr decreased from 0.7111 to values in the range 0.7107-0.7109 during early basin filling. 87Sr/86Sr values from a recently identified marl in the Las Vegas area are within the range of Bouse Sr ratios. 87Sr/86Sr values from the Hualapai Limestone decrease upsection from 0.7195 to 0.7137, in the approach to a time soon after 6 Ma when Hualapai deposition ceased and the Colorado River became established through the Lake Mead area. Bouse Formation ??18O values range from -12.9??? to +1.0??? Vienna Pee Dee belemnite (VPDB), and ??13C between -6.5??? and +3.4??? VPDB. Negative ??18O values appear to require a continental origin for waters, and the trend to higher ??18O suggests evaporation in lake waters. Sr and stable isotopic results for sectioned barnacle shells and from bedding planes of the marine fish fossil Colpichthys regis demonstrate that these animals lived in saline freshwater, and that there is no evidence for incursions of marine water, either long-lived or brief in duration. Lack of correlation of Sr and O isotopic variations in the same samples also argue strongly against systematic

  14. Space Radar Image of Colorado River

    NASA Image and Video Library

    1999-04-15

    This space radar image illustrates the recent rapid urban development occurring along the lower Colorado River at the Nevada/Arizona state line. Lake Mojave is the dark feature that occupies the river valley in the upper half of the image.

  15. Grand Canyon, Lake Powell, and Lake Mead

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A snowfall in the American West provides contrast to the landscape's muted earth tones and indicates changes in topography and elevation across (clockwise from top left) Nevada, Utah, Colorado, New Mexico, Arizona, and California. In Utah, the southern ranges of the Wasatch Mountains are covered in snow, and the Colorado River etches a dark ribbon across the red rock of the Colorado Plateau. In the center of the image is the reservoir created by the Glen Canyon Dam. To the east are the gray-colored slopes of Navaho Mountain, and to the southeast, dusted with snow is the region called Black Mesa. Southwest of Glen Canyon, the Colorado enters the Grand Canyon, which cuts westward through Arizona. At a deep bend in the river, the higher elevations of the Keibab Plateau have held onto snow. At the end of the Grand Canyon lies another large reservoir, Lake Mead, which is formed by the Hoover Dam. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  16. 75 FR 22063 - Endangered and Threatened Wildlife and Plants; 90-day Finding on a Petition to List the Mohave...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-27

    ... squirrel was found to consume leaves of annual and perennial plants, their fruits and seeds, fungi, and... mechanisms; or (e) Other natural or manmade factors affecting its continued existence. (4) Information on... affect the conservation of the Mohave ground squirrel. (6) Information on the population status of...

  17. Numerical modeling of the Snowmass Creek paleoglacier, Colorado, and climate in the Rocky Mountains during the Bull Lake glaciation (MIS 6)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Eric M. Leonard; Mitchell A. Plummer; Paul E. Carrara

    2014-04-01

    Well-preserved moraines from the penultimate, or Bull Lake, glaciation of Snowmass Creek Valley in the Elk Range of Colorado present an opportunity to examine the character of the high-altitude climate in the Rocky Mountains during Marine Oxygen Isotope Stage 6. This study employs a 2-D coupled mass/energy balance and flow model to assess the magnitudes of temperature and precipitation change that could have sustained the glacier in mass-balance equilibrium at its maximum extent during the Bull Lake glaciation. Variable substrate effects on glacier flow and ice thickness make the modeling somewhat more complex than in geologically simpler settings. Model resultsmore » indicate that a temperature depression of about 6.7°C compared with the present (1971–2000 AD) would have been necessary to sustain the Snowmass Creek glacier in mass-balance equilibrium during the Bull Lake glaciation, assuming no change in precipitation amount or seasonality. A 50% increase or decrease from modern precipitation would have been coupled with 5.2°C and 9.1°C Bull Lake temperature depressions respectively. Uncertainty in these modeled temperature depressions is about 1°C.« less

  18. Geologic map of the Callville Bay Quadrangle, Clark County, Nevada, and Mohave County, Arizona

    USGS Publications Warehouse

    Anderson, R. Ernest

    2003-01-01

    Report: 139 Map Scale: 1:24,000 Map Type: colored geologic map A 1:24,000-scale, full-color geologic map and four cross sections of the Callville Bay 7-minute quadrangle in Clark County, Nevada and Mohave County, Arizona. An accompanying text describes 21 stratigraphic units of Paleozoic and Mesozoic sedimentary rocks and 40 units of Cenozoic sedimentary, volcanic, and intrusive rocks. It also discusses the structural setting, framework, and history of the quadrangle and presents a model for its tectonic development.

  19. Climate Variability: Adaptation Strategies for Colorado River Management

    NASA Astrophysics Data System (ADS)

    Fulp, T. J.; Prairie, J. R.

    2008-12-01

    The importance of the Colorado River system to the western United States and the Republic of Mexico is well documented. Much has been written recently in response to the lingering drought and increasing demands on the system. Questions such as "has the river run out of water?", "how low can it go?", and "will Lake Mead go dry?" express the concern that the river system will be hard-pressed to continue to meet future demands, particularly if droughts tend toward increased magnitudes and longer durations. Reservoirs on the main stream of the Colorado River are managed by the Bureau of Reclamation (Reclamation), on behalf of the Secretary of the U.S. Department of the Interior (Secretary). Over 80% of the 60 million acre-feet of storage capacity is contained in Lake Powell and Lake Mead, large reservoirs that are located in each of the sub-basins (Upper Basin and Lower Basin) defined in the 1922 Colorado River Compact. In response to the worst drought conditions in approximately one hundred years of recorded history and the lack of specific operational guidelines for operation of Lake Powell and Lake Mead for drought and low reservoir conditions, the Secretary adopted new operational guidelines in December 2007 that will be used for an interim period (through 2026). The Interim Guidelines were the result of an intense, three-year effort in accordance with the National Environmental Policy Act of 1969 (NEPA). Several alternative operational rules were compared with respect to future potential impacts to Colorado River resources, including lake levels, water delivery, hydropower production, water quality, recreation, and fish and wildlife and published in an Environmental Impact Statement (EIS). Due to the large uncertainty regarding future inflows into the system, particularly in a changing climate, these comparisons were presented in probabilistic terms in order to assess the risk of key events (e.g., the timing and magnitude of water shortages). Because it is

  20. Recent ecological and biogeochemical changes in alpine lakes of Rocky Mountain National Park (Colorado, USA): A response to anthropogenic nitrogen deposition

    USGS Publications Warehouse

    Wolfe, A.P.; Van Gorp, A.C.; Baron, Jill S.

    2003-01-01

    Dated sediment cores from five alpine lakes (>3200 m asl) in Rocky Mountain National Park (Colorado Front Range, USA) record near-synchronous stratigraphic changes that are believed to reflect ecological and biogeochemical responses to enhanced nitrogen deposition from anthropogenic sources. Changes in sediment proxies include progressive increases in the frequencies of mesotrophic planktonic diatom taxa and diatom concentrations, coupled with depletions of sediment δ15N and C : N values. These trends are especially pronounced since approximately 1950. The most conspicuous diatoms to expand in recent decades are Asterionella formosa and Fragilaria crotonensis. Down-core species changes are corroborated by a year-long sediment trap experiment from one of the lakes, which reveals high frequencies of these two taxa during autumn and winter months, the interval of peak annual limnetic [NO3-]. Although all lakes record recent changes, the amplitude of stratigraphic shifts is greater in lakes east of the Continental Divide relative to those on the western slope, implying that most nitrogen enrichment originates from urban, industrial and agricultural sources east of the Rocky Mountains. Deviations from natural trajectories of lake ontogeny are illustrated by canonical correspondence analysis, which constrains the diatom record as a response to changes in nitrogen biogeochemistry. These results indicate that modest rates of anthropogenic nitrogen deposition are fully capable of inducing directional biological and biogeochemical shifts in relatively pristine ecosystems.

  1. 77 FR 12874 - Notice of Segregation of Public Lands in the State of Arizona Associated With the Proposed Mohave...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-02

    ...; AZA32315] Notice of Segregation of Public Lands in the State of Arizona Associated With the Proposed Mohave... material sales acts, for a period of 2 years. This segregation is being made in connection with the BLM's... County Wind Farm Project (Proposed Project). This segregation covers approximately 38,016.60 acres of BLM...

  2. Isolation and characterization of two disintegrins inhibiting ADP-induced human platelet aggregation from the venom of Crotalus scutulatus scutulatus (Mohave Rattlesnake)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sanchez, Elda E.; Galan, Jacob A.; Russell, William K.

    2006-04-01

    Disintegrins and disintegrin-like proteins are molecules found in the venom of four snake families (Atractaspididae, Elapidae, Viperidae, and Colubridae). The disintegrins are nonenzymatic proteins that inhibit cell-cell interactions, cell-matrix interactions, and signal transduction, and may have potential in the treatment of strokes, heart attacks, cancers, and osteoporosis. Prior to 1983, the venom of Crotalus scutulatus scutulatus (Mohave Rattlesnake) was known to be only neurotoxic; however, now there is evidence that these snakes can contain venom with: (1) neurotoxins; (2) hemorrhagins; and (3) both neurotoxins and hemorrhagins. In this study, two disintegrins, mojastin 1 and mojastin 2, from the venom ofmore » a Mohave rattlesnake collected in central Arizona (Pinal County), were isolated and characterized. The disintegrins in these venoms were identified by mass-analyzed laser desorption ionization/time-of-flight/time-of-flight (MALDI/TOF/TOF) mass spectrometry as having masses of 7.436 and 7.636 kDa. Their amino acid sequences are similar to crotratroxin, a disintegrin isolated from the venom of the western diamondback rattlesnake (C. atrox). The amino acid sequence of mojastin 1 was identical to the amino acid sequence of a disintegrin isolated from the venom of the Timber rattlesnake (C. horridus). The disintegrins from the Mohave rattlesnake venom were able to inhibit ADP-induced platelet aggregation in whole human blood both having IC{sub 5}s of 13.8 nM, but were not effective in inhibiting the binding of human urinary bladder carcinoma cells (T24) to fibronectin.« less

  3. Season-ahead Drought Forecast Models for the Lower Colorado River Authority in Texas

    NASA Astrophysics Data System (ADS)

    Block, P. J.; Zimmerman, B.; Grzegorzewski, M.; Watkins, D. W., Jr.; Anderson, R.

    2014-12-01

    The Lower Colorado River Authority (LCRA) in Austin, Texas, manages the Highland Lakes reservoir system in Central Texas, a series of six lakes on the Lower Colorado River. This system provides water to approximately 1.1 million people in Central Texas, supplies hydropower to a 55-county area, supports rice farming along the Texas Gulf Coast, and sustains in-stream flows in the Lower Colorado River and freshwater inflows to Matagorda Bay. The current, prolonged drought conditions are severely taxing the LCRA's system, making allocation and management decisions exceptionally challenging, and affecting the ability of constituents to conduct proper planning. In this work, we further develop and evaluate season-ahead statistical streamflow and precipitation forecast models for integration into LCRA decision support models. Optimal forecast lead time, predictive skill, form, and communication are all considered.

  4. 75 FR 19246 - Safety Zone; Desert Storm, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ...-AA00 Safety Zone; Desert Storm, Lake Havasu, AZ AGENCY: Coast Guard, DHS. ACTION: Temporary final rule... navigable waters of the Colorado River in Lake Havasu, Lake Havasu City, Arizona in support of the Desert.... Background and Purpose The Lake Racer LLC is sponsoring the Desert Storm Charity Poker Run and Exhibition Run...

  5. Lake Mead, NV

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead. In this harsh desert environment, color infrared photography readily penetrates haze, detects and portrays vegetation as shades of red.

  6. Geologic map of the Peach Springs 30' x 60' quadrangle, Mohave and Coconino counties, northwestern Arizona

    USGS Publications Warehouse

    Billingsley, George H.; Block, Debra L.; Dyer, Helen C.

    2006-01-01

    This map is a product of a cooperative project of the U.S. Geological Survey, the U.S. National Park Service, and the Bureau of Land Management to provide geologic map coverage and regional geologic information for visitor services and resource management of Grand Canyon National Park, Lake Mead National Recreation Area, Grand Canyon-Parashant-National Monument, and adjacent lands in northwestern Arizona. This map is a synthesis of previous and new geologic mapping that encompasses the Peach Springs 30' x 60' quadrangle, Arizona. The geologic data will support future geologic, biologic, hydrologic, and other science resource studies of this area conducted by the National Park Service, the Hualapai Indian Tribe, the Bureau of Land Management, the State of Arizona, and private organizations. The Colorado River and its tributaries have dissected the southwestern Colorado Plateau into what is now the southwestern part of Grand Canyon. The erosion of Grand Canyon has exposed about 426 m (1,400 ft) of Proterozoic crystalline metamorphic rocks and granite, about 1,450 m (4,760 ft) of Paleozoic strata, and about 300 m (1,000 ft) of Tertiary sedimentary rocks. Outcrops of Proterozoic crystalline rocks are exposed at the bottom of Grand Canyon at Granite Park from Colorado River Mile 207 to 209, at Mile 212, and in the Lower Granite Gorge from Colorado River Mile 216 to 262, and along the Grand Wash Cliffs in the southwest corner of the map area.

  7. Use of natural 35S to trace sulphate cycling in small lakes, Flattops Wilderness Area, Colorado, U.S.A.

    USGS Publications Warehouse

    Michel, Robert L.; Turk, John T.; Campbell, Donald H.; Mast, M. Alisa

    2002-01-01

    Measurements of the cosmogenically-produced 35S, a radioisotope of sulphur (t1/2 = 87 days), are reported for the Ned Wilson Lake watershed in Colorado. The watershed contains two small lakes and a flowing spring presumed to be representative of local ground water. The watershed is located in the Flattops Wilderness Area and the waters in the system have low alkalinity, making them sensitive to increases in acid and sulphate deposition. Time series of 35S measurements were made during the summers of 1995 and 1996 (July–September) at all three sites. The system is dominated by melting snow and an initial concentration of 16–20 mBq L-1was estimated for snowmelt based on a series of snow samples collected in the Rocky Mountains. The two lakes had large initial 35S concentrations in July, indicating that a large fraction of the lake water and sulphate was introduced by meltwater from that year's snowpack. In 1995 and 1996, 35S concentrations decreased more rapidly than could be accounted for by decay, indicating that other processes were affecting 35S concentrations. The most likely explanation is that exchange with sediments or the biota was removing 35S from the lake and replacing it with older sulphate devoid of 35S. In September of 1995 and 1996, 35S concentrations increased, suggesting that atmospheric deposition is important in the sulphate flux of these lakes in late summer. Sulphur-35 concentrations in the spring water were highly variable but never higher than 3.6 mBq L-1 and averaged 2 mBq L-1. Using a simple mixing model, it was estimated that 75% of the spring water was derived from precipitation of previous years.

  8. Trends in lake chemistry in response to atmospheric deposition and climate in selected Class I wilderness areas in Colorado, Idaho, Utah, and Wyoming, 1993-2009

    USGS Publications Warehouse

    Mast, M. Alisa; Ingersoll, George P.

    2011-01-01

    In 2010, the U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Forest Service, Air Resource Management, began a study to evaluate long-term trends in lake-water chemistry for 64 high-elevation lakes in selected Class I wilderness areas in Colorado, Idaho, Utah, and Wyoming during 1993 to 2009. The purpose of this report is to describe trends in the chemical composition of these high-elevation lakes. Trends in emissions, atmospheric deposition, and climate variables (air temperature and precipitation amount) are evaluated over a similar period of record to determine likely drivers of changing lake chemistry. Sulfate concentrations in precipitation decreased over the past two decades at high-elevation monitoring stations in the Rocky Mountain region. The trend in deposition chemistry is consistent with regional declines in sulfur dioxide emissions resulting from installation of emission controls at large stationary sources. Trends in nitrogen deposition were not as widespread as those for sulfate. About one-half of monitoring stations showed increases in ammonium concentrations, but few showed significant changes in nitrate concentrations. Trends in nitrogen deposition appear to be inconsistent with available emission inventories, which indicate modest declines in nitrogen emissions in the Rocky Mountain region since the mid-1990s. This discrepancy may reflect uncertainties in emission inventories or changes in atmospheric transformations of nitrogen species that may be affecting deposition processes. Analysis of long-term climate records indicates that average annual mean air temperature minimums have increased from 0.57 to 0.75 °C per decade in mountain areas of the region with warming trends being more pronounced in Colorado. Trends in annual precipitation were not evident over the period 1990 to 2006, although wetter than average years during 1995 to 1997 and drier years during 2001 to 2004 caused a notable decline in precipitation

  9. Geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado

    USGS Publications Warehouse

    Shroba, Ralph R.; Kellogg, Karl S.; Brandt, Theodore R.

    2014-01-01

    The geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado, portrays the geology in the upper Arkansas valley and along the lower flanks of the Sawatch Range and Mosquito Range near the town of Granite. The oldest rocks, exposed in the southern and eastern parts of the quadrangle, include gneiss and plutonic rocks of Paleoproterozoic age. These rocks are intruded by younger plutonic rocks of Mesoproterozoic age. Felsic hypabyssal dikes, plugs, and plutons, ranging in age from Late Cretaceous or Paleocene to late Oligocene, locally intruded Proterozoic rocks. A small andesite lava flow of upper Oligocene age overlies Paleoproterozoic rock, just south of the Twin Lakes Reservoir. Gravelly fluvial and fan deposits of the Miocene and lower Pliocene(?) Dry Union Formation are preserved in the post-30 Ma upper Arkansas valley graben, a northern extension of the Rio Grande rift. Mostly north-northwest-trending faults displace deposits of the Dry Union Formation and older rock units. Light detection and ranging (lidar) imagery suggests that two short faults, near the Arkansas River, may displace surficial deposits as young as middle Pleistocene. Surficial deposits of middle Pleistocene to Holocene age are widespread in the Granite quadrangle, particularly in the major valleys and on slopes underlain by the Dry Union Formation. The main deposits are glacial outwash and post-glacial alluvium; mass-movement deposits transported by creep, debris flow, landsliding, and rockfall; till deposited during the Pinedale, Bull Lake, and pre-Bull Lake glaciations; rock-glacier deposits; and placer-tailings deposits formed by hydraulic mining and other mining methods used to concentrate native gold. Hydrologic and geologic processes locally affect use of the land and locally may be of concern regarding the stability of buildings and infrastructure, chiefly in low-lying areas along and near stream channels and locally in areas of moderate to steep slopes. Low

  10. Lake Mead, NV

    NASA Image and Video Library

    1973-06-22

    SL2-03-192 (22 June 1973) --- Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead. In this harsh desert environment, color infrared photography readily penetrates haze, detects and portrays vegetation as shades of red. Photo credit: NASA

  11. Geologic map of the Hiller Mountain Quadrangle, Clark County, Nevada, and Mohave County, Arizona

    USGS Publications Warehouse

    Howard, Keith A.; Hook, Simon; Phelps, Geoffrey A.; Block, Debra L.

    2003-01-01

    Map Scale: 1:24,000 Map Type: colored geologic map The Hiller Mountains Quadrangle straddles Virgin Canyon in the eastern part of Lake Mead. Proterozoic gneisses and granitoid rocks underlie much of the quadrangle. They are overlain by upper Miocene basin-filling deposits of arkosic conglomerate, basalt, and the overlying Hualapai Limestone. Inception of the Colorado River followed deposition of the Hualapai Limestone and caused incision of the older rocks. Fluvial gravel deposits indicate various courses of the early river across passes through highlands of the Gold Butte-Hiller Mountains-White Hills structural block. Faults and tilted rocks in the quadrangle record tectonic extension that climaxed in middle Miocene time.

  12. Water quality and trend analysis of Colorado--Big Thompson system reservoirs and related conveyances, 1969 through 2000

    USGS Publications Warehouse

    Stevens, Michael R.

    2003-01-01

    The U.S. Geological Survey, in an ongoing cooperative monitoring program with the Northern Colorado Water Conservancy District, Bureau of Reclamation, and City of Fort Collins, has collected water-quality data in north-central Colorado since 1969 in reservoirs and conveyances, such as canals and tunnels, related to the Colorado?Big Thompson Project, a water-storage, collection, and distribution system. Ongoing changes in water use among agricultural and municipal users on the eastern slope of the Rocky Mountains in Colorado, changing land use in reservoir watersheds, and other water-quality issues among Northern Colorado Water Conservancy District customers necessitated a reexamination of water-quality trends in the Colorado?Big Thompson system reservoirs and related conveyances. The sampling sites are on reservoirs, canals, and tunnels in the headwaters of the Colorado River (on the western side of the transcontinental diversion operations) and the headwaters of the Big Thompson River (on the eastern side of the transcontinental diversion operations). Carter Lake Reservoir and Horsetooth Reservoir are off-channel water-storage facilities, located in the foothills of the northern Colorado Front Range, for water supplied from the Colorado?Big Thompson Project. The length of water-quality record ranges from approximately 3 to 30 years depending on the site and the type of measurement or constituent. Changes in sampling frequency, analytical methods, and minimum reporting limits have occurred repeatedly over the period of record. The objective of this report was to complete a retrospective water-quality and trend analysis of reservoir profiles, nutrients, major ions, selected trace elements, chlorophyll-a, and hypolimnetic oxygen data from 1969 through 2000 in Lake Granby, Shadow Mountain Lake, and the Granby Pump Canal in Grand County, Colorado, and Horsetooth Reservoir, Carter Lake, Lake Estes, Alva B. Adams Tunnel, and Olympus Tunnel in Larimer County, Colorado

  13. Water quality of Lake Austin and Town Lake, Austin, Texas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Andrews, F.L.; Wells, F.C.; Shelby, W.J.

    1988-01-01

    Lake Austin and Town Lake are impoundments on the Colorado River in Travis County, central Texas, and are a source of water for municipal industrial water supplies, electrical-power generation, and recreation for more than 500,000 people in the Austin metropolitan area. Small vertical temperature variations in both lakes were attributed to shallow depths in the lakes and short retention times of water in the lakes during the summer months. The largest areal variations in dissolved oxygen generally occur in Lake Austin during the summer as a result of releases of water from below the thermocline in Lake Travis. Except formore » iron, manganese, and mercury, dissolved concentrations of trace elements in water collected from Lake Austin and Town Lake did not exceed the primary or secondary drinking water standards set by the US Environmental Protection Agency. Little or no effect of stormwater runoff on temperature, dissolved oxygen, or minor elements could be detected in either Lake Austin or Town Lake. Little seasonal or areal variation was noted in nitrogen concentrations in Lake Austin or Town lake. Total phosphorus concentrations generally were small in both lakes. Increased concentrations of nitrogen and phosphorus were detected after storm runoff inflow in Town Lake, but not in Lake Austin; densities of fecal-coliform bacteria increased in Lake Austin and Town Lake, but were substantially greater in Town Lake than in Lake Austin. 18 refs., 38 figs., 59 tabs.« less

  14. Evaporation from Lake Mead, Arizona and Nevada, 1997-99

    USGS Publications Warehouse

    Westenburg, Craig L.; DeMeo, Guy A.; Tanko, Daron J.

    2006-01-01

    Lake Mead is one of a series of large Colorado River reservoirs operated and maintained by the Bureau of Reclamation. The Colorado River system of reservoirs and diversions is an important source of water for millions of people in seven Western States and Mexico. The U.S. Geological Survey, in cooperation with the Bureau of Reclamation, conducted a study from 1997 to 1999 to estimate evaporation from Lake Mead. For this study, micrometeorological and hydrologic data were collected continually from instrumented platforms deployed at four locations on the lake, open-water areas of Boulder Basin, Virgin Basin, and Overton Arm and a protected cove in Boulder Basin. Data collected at the platforms were used to estimate Lake Mead evaporation by solving an energy-budget equation. The average annual evaporation rate at open-water stations from January 1998 to December 1999 was 7.5 feet. Because the spatial variation of monthly and annual evaporation rates was minimal for the open-water stations, a single open-water station in Boulder Basin would provide data that are adequate to estimate evaporation from Lake Mead.

  15. Natural variance in pH as a complication in detecting acidification of lakes

    USGS Publications Warehouse

    Turk, J.T.

    1988-01-01

    Natural variance in the pH of three dilute lakes in the Flat Tops Wilderness Area, Colorado, complicates the detection of acidification. Variations in pH during July-September of 1983 were: 0.95 (Ned Wilson Lake), 1.36 (Upper Island Lake), and 1.53 (Oyster Lake). Mean diurnal variations in pH during 1983 were: 0.37 (Ned Wilson Lake), 0.54 (Upper Island Lake), and 0.39 (Oyster Lake). Replicate pH measurements indicate that pH can be measured with a mean variance due to measurement error of ?? 0.005. Regression analysis indicates that samples collected on the same day of different years may differ because of time of day and percentage of cloud cover. Differences in wind duration and intensity and primary productivity also may cause the pH to differ between years. Such differences can be either random or systematic. Comparisons of pH among 3 yr of data from Ned Wilson Lake indicate that natural variations in pH are much larger than variations in Colorado Lakes previously attributed to acidification by precipitation.

  16. Specific Conductance in the Colorado River between Glen Canyon Dam and Diamond Creek, Northern Arizona, 1988-2007

    USGS Publications Warehouse

    Voichick, Nicholas

    2008-01-01

    The construction of Glen Canyon Dam, completed in 1963, resulted in substantial physical and biological changes to downstream Colorado River environments between Lake Powell and Lake Mead - an area almost entirely within Grand Canyon National Park, Ariz. In an effort to understand these changes, data have been collected to assess the condition of a number of downstream resources. In terms of measuring water quality, the collection of specific-conductance data is a cost-effective method for estimating salinity. Data-collection activities were initially undertaken by the Bureau of Reclamation's Glen Canyon Environmental Studies (1982-96); these efforts were subsequently transferred to the U.S. Geological Survey's Grand Canyon Monitoring and Research Center (1996 to the present). This report describes the specific-conductance dataset collected for the Colorado River between Glen Canyon Dam and Diamond Creek from 1988 to 2007. Data-collection and processing methods used during the study period are described, and time-series plots of the data are presented. The report also includes plots showing the relation between specific conductance and total dissolved solids. Examples of the use of specific conductance as a natural tracer of parcels of water are presented. Analysis of the data indicates that short-duration spikes and troughs in specific-conductance values lasting from hours to days are primarily the result of flooding in the Paria and Little Colorado Rivers, Colorado River tributaries below Glen Canyon Dam. Specific conductance also exhibits seasonal variations owing to changes in the position of density layers within the reservoir; these changes are driven by inflow hydrology, meteorological conditions, and background stratification. Longer term trends in Colorado River specific conductance are reflective of climatological conditions in the upper Colorado River Basin. For example, drought conditions generally result in an increase in specific conductance in Lake

  17. The binding effectiveness of anti-r-disintegrin polyclonal antibodies against disintegrins and PII and PIII metalloproteases: An immunological survey of type A, B and A + B venoms from Mohave rattlesnakes

    PubMed Central

    Cantú, Esteban; Mallela, Sahiti; Nyguen, Matthew; Báez, Raúl; Parra, Victoria; Johnson, Rachel; Wilson, Kyle; Suntravat, Montamas; Lucena, Sara; Rodríguez-Acosta, Alexis; Sánchez, Elda E.

    2016-01-01

    Snake venoms are known to have different venom compositions and toxicity, but differences can also be found within populations of the same species contributing to the complexity of treatment of envenomated victims. One of the first well-documented intraspecies venom variations comes from the Mohave rattlesnake (Crotalus scutulatus scutulatus). Initially, three types of venoms were described; type A venom is the most toxic as a result of ~45% Mojave toxin in the venom composition, type B lacks the Mojave toxin but contains over 50% of snake venom metalloproteases (SVMPs). Also, type A + B venom contains a combination of Mojave toxin and SVMP. The use of an anti-disintegrin antibody in a simple Enzyme-Linked Immunosorbent Assay (ELISA) can be used to identify the difference between the venoms of the type A, B, and A+B Mohave rattlesnakes. This study implements the use of an anti-recombinant disintegrin polyclonal antibody (ARDPA) for the detection of disintegrins and ADAMs (a disintegrin and metalloproteases) in individual crude snake venoms of Mohave rattlesnakes (Crotalus scutulatus scutulatus) of varying geographical locations. After correlation with Western blots, coagulation activity and LD50 data, it was determined that the antibody allows for a quick and cost-efficient identification of venom types. PMID:27989783

  18. Tracing Changes in Carbon Chemistry Caused by an Extreme Mid-Summer Rain Event in a Lake-Stream System in the Colorado Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Miller, M.; McKnight, D.; Alexander, K.

    2006-12-01

    We studied the impact of a sustained high elevation rain event in mid-summer on the biogeochemistry of dissolved organic material (DOM) in an aquatic ecosystem in the Colorado Front Range. In the Green Lakes Valley, an alpine-subalpine catchment, the hydrology is typically defined by two distinct periods: snowmelt and baseflow. Similarly, characterization of DOM by fluorescence spectroscopy and other methods shows that the source and chemical character of the DOM changes with the hydrology. Surface water samples were collected from the outlet of a small alpine lake as well as a stream site downstream of a larger subalpine lake from the initiation of snowmelt through late summer. Beginning on July 7th and ending on July 9th 2006 a continuous low intensity rain event produced approximately 9 cm of precipitation. The rain event increased discharge at the two sites to flow rates that were 2.5 fold greater than those observed during peak snowmelt. The fluorescence characteristics of the DOM as well as the percent fulvic acid contribution to the sample were reset to values similar to those observed during snowmelt at the alpine site but were relatively unaffected at the subalpine site. These results suggest that alpine ecosystems are more sensitive to hydrologic changes than subalpine ecosystems and residence times of the lakes in these systems may play an important role in regulating stream chemistry.

  19. NPDES Permit for Leadville Mine Drainage Tunnel Treatment Plant in Colorado

    EPA Pesticide Factsheets

    Under NPDES permit CO-0021717, the U.S. Bureau of Reclamation is authorized to discharge from the Leadville Mine Drainage Tunnel Treatment Plant in Lake County, Colorado to an unnamed drainage way tributary to the East Fork of the Arkansas River.

  20. Occurrence and distribution of molybdenum in the surface waters of Colorado geochemistry of water

    USGS Publications Warehouse

    Voegeli, Paul Thomas; King, Robert Ugstad

    1969-01-01

    Molybdenum was detected in 89 percent of the samples collected from all the principal Colorado streams and their chief tributaries and from a few reservoirs and lakes. Amounts detected ranged from 1 to 3,800 micrograms per liter. The greatest amounts of molybdenum detected were in samples from the Colorado River at and below Kremmling, the Dillon Reservoir, the Blue River below Dillon Dam, the Eagle River, and Tenmile Creek.

  1. Water Demand Management Strategies and Challenges in the Upper Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Kuhn, R. E.

    2016-12-01

    Under the 1922 Colorado River Compact, the Upper Basin (Colorado, New Mexico, Utah, and Wyoming) has flow obligations at Lee Ferry to downstream states and Mexico. The Colorado River Storage Project Act (CRSPA) of 1956 led to the construction of four large storage reservoirs. These provide river regulation to allow the Upper Basin to meet its obligations. Lake Powell, the largest and most important, and Lake Mead are now operated in a coordinated manner under the 2007 Interim Guidelines. Studies show that at current demand levels and if the hydrologic conditions the Basin has experienced since the mid-1980s continue or get drier, reservoir operations, alone, may not provide the necessary water to meet the Upper Basin's obligations. Therefore, the Upper Basin states are now studying demand management strategies that will reduce consumptive uses when total system reservoir storage reaches critically low levels. Demand management has its own economic, political and technical challenges and limitations and will provide new opportunities for applied research. This presentation will discuss some of those strategies, their challenges, and the kinds of information that research could provide to inform demand management.

  2. Geologic Map of the Upper Parashant Canyon and Vicinity, Mohave County, Northwestern Arizona

    USGS Publications Warehouse

    Billingsley, George H.; Harr, Michelle L.; Wellmeyer, Jessica L.

    2000-01-01

    Introduction The geologic map of the upper Parashant Canyon area covers part of the Colorado Plateau and several large tributary canyons that make up the western part of Arizona's Grand Canyon. The map is part of a cooperative U.S. Geological Survey and National Park Service project to provide geologic information for areas within the newly established Grand Canyon/Parashant Canyon National Monument. Most of the Grand Canyon and parts of the adjacent plateaus have been geologically mapped; this map fills in one of the remaining areas where uniform quality geologic mapping was needed. The geologic information presented may be useful in future related studies as to land use management, range management, and flood control programs for federal and state agencies, and private concerns. The map area is in a remote region of the Arizona Strip, northwestern Arizona about 88 km south of the nearest settlement of St. George, Utah. Elevations range from about 1,097 m (3,600 ft) in Parashant Canyon (south edge of map area) to 2,145 m (7,037 ft) near the east-central edge of the map area. Primary vehicle access is by dirt road locally known as the Mount Trumbull road; unimproved dirt roads and jeep trails traverse various parts of the map area. Travel on the Mount Trumbull road is possible with 2-wheel-drive vehicles except during wet conditions. Extra fuel, two spare tires and extra food and water are highly recommended when traveling in this remote area. The map area includes about 26 sections of land belonging to the State of Arizona, about 40 sections of private land, and a small strip of the Lake Mead National Recreation Area (southeast edge of the map area). The private land is mainly clustered around the abandoned settlement of Mt. Trumbull, locally known as Bundyville, and a few sections are scattered in the upper Whitmore Canyon area just south of Bundyville. Lower elevations within the canyons support a sparse growth of sagebrush, cactus, grass, creosote bush, and a

  3. Using Multi-Objective Optimization to Explore Robust Policies in the Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Alexander, E.; Kasprzyk, J. R.; Zagona, E. A.; Prairie, J. R.; Jerla, C.; Butler, A.

    2017-12-01

    The long term reliability of water deliveries in the Colorado River Basin has degraded due to the imbalance of growing demand and dwindling supply. The Colorado River meanders 1,450 miles across a watershed that covers seven US states and Mexico and is an important cultural, economic, and natural resource for nearly 40 million people. Its complex operating policy is based on the "Law of the River," which has evolved since the Colorado River Compact in 1922. Recent (2007) refinements to address shortage reductions and coordinated operations of Lakes Powell and Mead were negotiated with stakeholders in which thousands of scenarios were explored to identify operating guidelines that could ultimately be agreed on. This study explores a different approach to searching for robust operating policies to inform the policy making process. The Colorado River Simulation System (CRSS), a long-term water management simulation model implemented in RiverWare, is combined with the Borg multi-objective evolutionary algorithm (MOEA) to solve an eight objective problem formulation. Basin-wide performance metrics are closely tied to system health through incorporating critical reservoir pool elevations, duration, frequency and quantity of shortage reductions in the objective set. For example, an objective to minimize the frequency that Lake Powell falls below the minimum power pool elevation of 3,490 feet for Glen Canyon Dam protects a vital economic and renewable energy source for the southwestern US. The decision variables correspond to operating tiers in Lakes Powell and Mead that drive the implementation of various shortage and release policies, thus affecting system performance. The result will be a set of non-dominated solutions that can be compared with respect to their trade-offs based on the various objectives. These could inform policy making processes by eliminating dominated solutions and revealing robust solutions that could remain hidden under conventional analysis.

  4. Paleomagnetism of the Middle Proterozoic Electra Lake Gabbro, Needle Mountains, southwestern Colorado

    USGS Publications Warehouse

    Harlan, S.S.; Geissman, J.W.

    1998-01-01

    The Electra Lake Gabbro is a small 1.435 Ga pluton that intrudes 1.7 to 1.6 Ga gneisses and schists of the Needle Mountains in southwestern Colorado. Paleomagnetic samples were collected from the main phases of the gabbro, diabase dikes, granite, and alaskite dikes that cut the gabbro and from a partially melted zone in gneiss along the southern margin of the pluton. Gabbro, diabase, and some melt zone samples have a single-polarity characteristic magnetization of northeast declination (D) and moderate negative inclination (I). Demagnetization behavior and rock magnetic characteristics indicate that the remanence is carried by nearly pure magnetite. After correction for the minor west dip of overlying Paleozoic strata, we obtain a mean direction of D = 32.1??, I = -41.9?? (k = 94, ??95 = 3.3??, N = 21 sites) and a paleomagnetic pole at 21.1?? S, 221.1 ??E, (K= 89, A95 = 3.4??). This pole is similar to poles from the Middle Proterozoic Belt Supergroup but is located at a higher southerly latitude than poles from other 1.47-1.44 Ga plutons from North America, most of which plot at equatorial latitudes. The reason for this discrepancy is not clear but may result from a combination of factors, including unrecognized tilting of the gabbro, the failure of this relatively small pluton to fully average paleosecular variation, and uncertainties in the overall reliability of other 1.5-1.4 Ga poles of the North American apparent polar wander path.

  5. Chapter 2. The Intermountain setting

    Treesearch

    E. Durant McArthur; Sherel K. Goodrich

    2004-01-01

    This book is intended to assist range managers throughout the Intermountain West (fig. 1). The areas of greatest applicability are the Middle and Southern Rocky Mountains, Wyoming Basin, Columbia and Colorado Plateaus, and much of the basin and range physiographic provinces of Fenneman (1981) or about 14° latitude, from the Mohave, Sonoran, and Chihuahuan...

  6. Spring-summer movements of bonytail in a Colorado River reservoir, Lake Mohave, Arizona and Nevada

    USGS Publications Warehouse

    Marsh, Paul C.; Mueller, Gordon

    1999-01-01

    Bonytail can move substantial distances in a short time (10s of km in a few days). Fish in both years apparently favored the same areas, where they may remain for weeks. Unmarked bonytail were observed or captured by setting nets in places favored by tagged fish, a significant result since future use of the technique may enhance our ability to monitor reintroductions, locate and document spawning, examine habitat use, and acquire desperately needed brood stock for this critically imperiled species. External tagging techniques developed for juvenile razorback sucker may provide a method of minimizing telemetry induced stress while allowing us to focus sampling on congregation sites.

  7. Crystal growth mechanisms in miarolitic cavities in the Lake George ring complex and vicinity, Colorado

    USGS Publications Warehouse

    Kile, D.E.; Eberl, D.D.

    1999-01-01

    The Crystal Peak area of the Pikes Peak batholith, near Lake George in central Colorado, is world-renowned for its crystals of amazonite (the blue-green variety of microcline) and smoky quartz. Such crystals, collected from individual miarolitic pegmatites, have a remakably small variation in crystal size within each pegmatite, and the shapes of plots of their crystal size distributions (CSDs) are invariably lognormal or close to lognormal in all cases. These observations are explained by a crystal growth mechanism that was governed initially by surface-controlled kinetics, during which crystals tended to grow larger in proportion to their size, thereby establishing lognormal CSDs. Surface-controlled growth was followed by longer periods of supply controlled growth, during which growth rate was predominantly size-independent, consequently preserving the lognormal shapes of the CSDs and the small size variation. The change from surface- to supply controlled growth kinetics may have resulted from an increasing demand for nutrients that exceeded diffusion limitations of the system. The proposed model for crystal growth in this locality appears to be common in the geologic record, and can be used with other information, such as isotopic data, to deduce physico-chemical conditions during crystal formation.

  8. Geologic map of the Harvard Lakes 7.5' quadrangle, Park and Chaffee Counties, Colorado

    USGS Publications Warehouse

    Kellogg, Karl S.; Lee, Keenan; Premo, Wayne R.; Cosca, Michael A.

    2013-01-01

    The Harvard Lakes 1:24,000-scale quadrangle spans the Arkansas River Valley in central Colorado, and includes the foothills of the Sawatch Range on the west and Mosquito Range on the east. The Arkansas River valley lies in the northern end of the Rio Grande rift and is structurally controlled by Oligocene and younger normal faults mostly along the west side of the valley. Five separate pediment surfaces were mapped, and distinctions were made between terraces formed by the Arkansas River and surfaces that formed from erosion and alluviation that emanated from the Sawatch Range. Three flood deposits containing boulders as long as 15 m were deposited from glacial breakouts just north of the quadrangle. Miocene and Pliocene basin-fill deposits of the Dry Union Formation are exposed beneath terrace or pediment deposits in several places. The southwestern part of the late Eocene Buffalo Peaks volcanic center, mostly andesitic breccias and flows and ash-flow tuffs, occupy the northeastern corner of the map. Dated Tertiary intrusive rocks include Late Cretaceous or early Paleocene hornblende gabbro and hornblende monzonite. Numerous rhyolite and dacite dikes of inferred early Tertiary or Late Cretaceous age also intrude the basement rocks. Basement rocks are predominantly Mesoproterozoic granites, and subordinately Paleoproterozoic biotite gneiss and granitic gneiss.

  9. Paleomagnetism of the Middle Proterozoic Electra Lake Gabbro, Needle Mountains, southwestern Colorado

    NASA Astrophysics Data System (ADS)

    Harlan, Stephen S.; Geissman, John W.

    1998-07-01

    The Electra Lake Gabbro is a small 1.435 Ga pluton that intrudes 1.7 to 1.6 Ga gneisses and schists of the Needle Mountains in southwestern Colorado. Paleomagnetic samples were collected from the main phases of the gabbro, diabase dikes, granite, and alaskite dikes that cut the gabbro and from a partially melted zone in gneiss along the southern margin of the pluton. Gabbro, diabase, and some melt zone samples have a single-polarity characteristic magnetization of northeast declination (D) and moderate negative inclination (I). Demagnetization behavior and rock magnetic characteristics indicate that the remanence is carried by nearly pure magnetite. After correction for the minor west dip of overlying Paleozoic strata, we obtain a mean direction of D = 32.1°, I = -41.9° ( k: = 94, α95 = 3.3°, N = 21 sites) and a paleomagnetic pole at 21.1°S, 221.1°E, (K = 89, A95 = 3.4°). This pole is similar to poles from the Middle Proterozoic Belt Supergroup but is located at a higher southerly latitude than poles from other 1.47-1.44 Ga plutons from North America, most of which plot at equatorial latitudes. The reason for this discrepancy is not clear but may result from a combination of factors, including unrecognized tilting of the gabbro, the failure of this relatively small pluton to fully average paleosecular variation, and uncertainties in the overall reliability of other 1.5-1.4 Ga poles of the North American apparent polar wander path.

  10. Geologic map of the Frisco quadrangle, Summit County, Colorado

    USGS Publications Warehouse

    Kellogg, Karl S.; Bartos, Paul J.; Williams, Cindy L.

    2002-01-01

    New 1:24,000-scale geologic mapping along the Interstate-70 urban corridor in western Colorado, in support of the USGS Central Region State/USGS Cooperative Geologic Mapping Project, is contributing to a more complete understanding of the stratigraphy, structure, tectonic evolution, and hazard potential of this rapidly developing region. The 1:24,000-scale Frisco quadrangle is near the headwaters of the Blue River and straddles features of the Blue River graben (Kellogg, K.S., 1999, Neogene basins of the northern Rio Grande rift?partitioning and asymmetry inherited from Laramide and older uplifts: Tectonophysics, v. 305, p. 141-152.), part of the northernmost reaches of the Rio Grande rift, a major late Oligocene to recent zone of extension that extends from Colorado to Mexico. The Williams Range thrust fault, the western structural margin of the Colorado Front Range, cuts the northeastern corner of the quadrangle. The oldest rocks in the quadrangle underlie the Tenmile Range and include biotite-sillimanite schist and gneiss, amphibolite, and migmatite that are intruded by granite inferred to be part of the 1,667-1,750 Ma Routt Plutonic Suite (Tweto, Ogden, 1987, Rock units of the Precambrian- basement in Colorado: U.S. Geological Survey Professional Paper 1321-A, 54 p.). The oldest sedimentary unit is the Pennsylvanian Maroon Formation, a sequence of red sandstone, conglomerate, and interbedded shale. The thickest sequence of sedimentary rocks is Cretaceous in age and includes at least 500 m of the Upper Cretaceous Pierre Shale. The sedimentary rocks are intruded by sills and dikes of dacite porphyry sills of Swan Mountain, dated at 44 Ma (Marvin, R.F., Mehnert, H.H., Naeser, C.W., and Zartman, R.E., 1989, U.S. Geological Survey radiometric ages, compilation ?C??Part five?Colorado, Montana, Utah, and Wyoming: Isochron/West, no. 53, p. 14-19. Simmons, E.C., and Hedge, C.E., 1978, Minor-element and Sr-isotope geochemistry of Tertiary stocks, Colorado mineral belt

  11. 77 FR 70121 - Special Local Regulation; Annual Marine Events on the Colorado River Between Davis Dam (Bullhead...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-23

    ... Local Regulation; Annual Marine Events on the Colorado River Between Davis Dam (Bullhead City, AZ) and... during the Lake Havasu City Boat Parade of Lights on December 01, 2012 from 5 p.m. to 9 p.m. This event... Lake Havasu City Boat Parade of Lights (Item 10 on Table 1 of 33 CFR 100.1102). The Coast Guard will...

  12. 78 FR 56692 - Colorado River Storage Project-Rate Order No. WAPA-161

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-13

    ... existing Salt Lake City Area Integrated Projects (SLCA/IP) Firm Power Rate and the Colorado River Storage Project (CRSP) Transmission and Ancillary Services Rates through September 30, 2015. The existing SLCA/IP... SLCA/IP Firm Power Rate and CRSP Transmission and Ancillary Services Rates under Rate Schedules SLIP-F9...

  13. Update of the Accounting Surface Along the Lower Colorado River

    USGS Publications Warehouse

    Wiele, Stephen M.; Leake, Stanley A.; Owen-Joyce, Sandra J.; McGuire, Emmet H.

    2008-01-01

    The accounting-surface method was developed in the 1990s by the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, to identify wells outside the flood plain of the lower Colorado River that yield water that will be replaced by water from the river. This method was needed to identify which wells require an entitlement for diversion of water from the Colorado River and need to be included in accounting for consumptive use of Colorado River water as outlined in the Consolidated Decree of the United States Supreme Court in Arizona v. California. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The study area includes the valley adjacent to the lower Colorado River and parts of some adjacent valleys in Arizona, California, Nevada, and Utah and extends from the east end of Lake Mead south to the southerly international boundary with Mexico. Contours for the original accounting surface were hand drawn based on the shape of the aquifer, water-surface elevations in the Colorado River and drainage ditches, and hydrologic judgment. This report documents an update of the original accounting surface based on updated water-surface elevations in the Colorado River and drainage ditches and the use of simple, physically based ground-water flow models to calculate the accounting surface in four areas adjacent to the free-flowing river.

  14. Peridotite-suite dominated mineral inclusions in diamonds from Kelsey Lake Mine, Colorado U.S.A.

    NASA Astrophysics Data System (ADS)

    Schulze, D. J.; Coopersmith, H. G.

    2005-12-01

    Thirty silicate and oxide inclusions large enough for in situ WDS electron microprobe analysis were exposed by grinding/polishing of 16 diamonds from the Kelsey Lake Mine in the Colorado-Wyoming State Line kimberlite district. Three garnets in two stones belong to the eclogite (E) suite, and 18 olivines, three Mg-chromites and six Cr-pyropes in the other 14 stones belong to the peridotite (P) suite. The peridotite-dominated population is in stark contrast to the other suites studied in the State Line district. The reported inclusion population from George Creek is completely eclogitic and that of the Sloan pipe is overwhelmingly eclogitic, with only a minor, relatively Fe-rich peridotite component. Multiple inclusions are common in single stones, with 12 olivines (of uniform composition) exposed in one example. Kelsey Lake olivine inclusions are magnesian (17 of 18 grains in 9 stones are in the range Fo 92.7-93.1), typical of P-suite stones worldwide, but unlike the more Fe-rich Sloan olivine suite (13 of 14 in the range Fo 91.3-92.2). Mg-chromites (wt percent MgO = 12.8-13.8, wt percent Cr2O3 = 61.4-66.6) are in the lower MgO range of diamond inclusion chromites worldwide. Six Cr-pyropes in four stones have moderately low calcium contents (wt percent CaO = 3.5-4.5) but are very Cr-rich (wt percent Cr2O3 = 10.5-16.7). An olivine-garnet pair in one stone yields a Mg-Fe exchange temperature of 895 degrees C, possibly indicating disequilibrium, whereas an olivine-chromite pair yields an Mg-Fe exchange temperature of 1035 degrees C, cool but reasonable for equilibration within the diamond stability field. Comparison with diamond inclusion minerals worldwide reveals that the Kesley Lake suite is most similar to those from the Slave Craton in Canada, especially in terms of Cr-pyrope compositions. Both suites are somewhat less depleted than suites from southern Africa or Siberian kimberlites. By analogy with the Slave P-suite diamonds of Archean age and a Proterozoic

  15. 1. AERIAL VIEW OF WHITSETT (INTAKE) PUMP PLANT ON LAKE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. AERIAL VIEW OF WHITSETT (INTAKE) PUMP PLANT ON LAKE SHORE IN FOREGROUND; GENE IN BACKGROUND, LOOKING SOUTHWEST. - Whitsett Pump Plant, West side of Colorado River, north of Parker Dam, Parker Dam, San Bernardino County, CA

  16. Nearshore thermal gradients of the Colorado River near the Little Colorado River confluence, Grand Canyon National Park, Arizona, 2010

    USGS Publications Warehouse

    Ross, Rob; Grams, Paul E.

    2013-01-01

    Construction and operation of Glen Canyon Dam has dramatically impacted the flow of the Colorado River through Glen, Marble, and Grand Canyons. Extremes in both streamflow and water temperature have been suppressed by controlled releases from the dam. Trapping of sediment in Lake Powell, the reservoir formed by Glen Canyon Dam, has also dramatically reduced the supply of suspended sediment entering the system. These changes have altered the riverine ecosystem and the habitat of native species, including fish such as the endangered humpback chub (Gila cypha). Most native fish are adapted to seasonally warm water, and the continuous relatively cold water released by the dam is one of the factors that is believed to limit humpback chub growth and survival. While average mainstem temperatures in the Colorado River are well documented, there is limited understanding of temperatures in the nearshore environments that fish typically occupy. Four nearshore geomorphic unit types were studied between the confluence of the Colorado and Little Colorado Rivers and Lava Canyon in the summer and fall of 2010, for study periods of 10 to 27 days. Five to seven sites were studied during each interval. Persistent thermal gradients greater than the 0.2 °C accuracy of the instruments were not observed in any of the sampled shoreline environments. Temperature gradients between the shoreline and mainstem on the order of 4 °C, believed to be important to the habitat-seeking behavior of native or nonnative fishes, were not detected.

  17. Sr isotope evidence for a lacustrine origin for the upper Miocene to Pliocene Bouse Formation, lower Colorado River trough, and implications for timing of Colorado Plateau uplift

    USGS Publications Warehouse

    Spencer, J.E.; Patchett, P.J.

    1997-01-01

    The upper Miocene to Pliocene Bouse Formation in the lower Colorado River trough, which consists largely of siltstone with basal tufa and marl, has been interpreted as estuarine on the basis of paleontology. This interpretation requires abrupt marine inundation that has been linked to early rifting in the Gulf of California and Salton trough. New strontium isotope measurements reported here from carbonates and invertebrate shells in the Bouse Formation reveal no evidence of marine water, but are consistent with deposition in a lake or chain of lakes fed by the Colorado River. Furthermore, the absence of a southward decrease in 87Sr/86Sr within the Bouse Formation does not support the estuarine model in which low 87Sr/86Sr marine Sr would have dominated the mouth of the hypothetical Bouse estuary. Elevation of originally marine 87Sr/86Sr in the Bouse Formation to its present level, due to postdepositional interaction with ground water, is unlikely because Sr from secondary calcite above, below, and within the Bouse Formation is consistently less radiogenic, not more, than Bouse marl and shells. In contrast to Bouse Sr, strontium from mollusks in tidal-flat and delta-front paleoenvironments in the contemporaneous Imperial Formation in the Salton trough and from the subsurface south of Yuma was derived from sea water and confirms the dominance of marine strontium near or at the mouth of the late Miocene to early Pliocene Colorado River. Inferred post-early Pliocene uplift of the Bouse Formation from below sea level to modern elevations of up to 550 m has been used to support a late Cenozoic uplift age for the nearby Colorado Plateau. This constraint on uplift timing is eliminated if the Bouse Formation is lacustrine.

  18. Geologic Map of Part of the Uinkaret Volcanic Field, Mohave County, Northwestern Arizona

    USGS Publications Warehouse

    Billingsley, George H.; Hamblin, W. Kenneth; Wellmeyer, Jessica L.; Dudash, Stephanie L.

    2001-01-01

    addition, there are 12 sections belonging to the State of Arizona, about 12 sections are private land, and several sections are within the Grand Canyon National Park and Lake Mead National Recreational Area (U.S. Department of the Interior, 1993). The private land is in Potato Valley and Lake Valley, southwest and west of Mount Trumbull, and in Whitmore Canyon and Toroweap (Tuweap) Valley. Portions of the Sawmill Mountains, Mount Logan, and Mount Trumbull areas were originally established as part of the Dixie National Forest in 1904. In 1924, Dixie National Forest land became part of the Kaibab National Forest. Then on February 13, 1974, management of this part of the Kaibab National Forest was transferred to the Bureau of Land Management, Arizona Strip Field Office (personal commun. Becky Hammond, Bureau of Land Management, 1997). Mount Logan and part of the Sawmill Mountains are now designated as the Mount Logan Wilderness Area, and Mount Trumbull is designated as the Mount Trumbull Wilderness Area. Most of the map area is now part of the new Grand Canyon-Parashant Canyon National Monument established January 11, 2000. Lower elevations within Hells Hollow, Whitmore Canyon, Toroweap Valley, and Cove Canyon support a sparse growth of sagebrush, cactus, grass, and a variety of desert shrubs. Sagebrush, grass, cactus, cliffrose bush, pinion pine, and juniper trees thrive at elevations above 1,830 m (6,000 ft). Ponderosa pine and oak forests thrive at higher elevations in the Mount Trumbull and Mount Logan areas. Surface runoff within the map area drains south towards the Colorado River through Hells Hole, Hollow, Whitmore Canyon, Toroweap Valley, and Cove Canyon. Upper Toroweap Valley, upper Hells Hollow, and Whitmore Canyon are part of the physiographic area of Grand Canyon, but are not within Grand Canyon National Park (Billingsley and others, 1997). As of January 11, 2000, these areas are now part of the new Grand Canyon-Parashant

  19. Lakes in the greater Denver area, Front Range Urban Corridor

    USGS Publications Warehouse

    Danielson, T.W.

    1975-01-01

    The purpose of this report is to present the results of an inventory of the lakes in the central one-third of the Colorado Front Range Urban Corridor. This inventory provides information that might be helpful in planning the best and most beneficial use of lakes in an area of rapid population growth. The report includes data on lake size and water quality. Size data are included on most of the lakes of 2 hectares (20,000 m2, or about 5 acres) or greater, and water-quality data are provided on most lakes larger than 10 hectares (about 25 acres). Bodies of water resulting form excavation of gravel (borrow pits) were generally not included in the inventory.

  20. Bighorn sheep response to road-related disturbances in Rocky Mountain National Park, Colorado

    USGS Publications Warehouse

    Keller, B.J.; Bender, L.C.

    2007-01-01

    Bighorn sheep (Ovis canadensis) use of Sheep Lakes mineral site, Rocky Mountain National Park, Colorado, USA, has decreased since 1996. Officials were concerned that human disturbance may have been contributing to this decline in use. We evaluated effects of vehicular traffic and other road-related disturbance on bighorn use of Sheep Lakes in the summers of 2002 and 2003. We found that the time and number of attempts required by bighorn to reach Sheep Lakes was positively related to the number of vehicles and people present at Sheep Lakes. Further, the number of bighorn individuals and groups attempting to visit Sheep Lakes were negatively affected by disturbance associated with the site. The number of vehicles recorded the hour before bighorn tried to access Sheep Lakes best predicted an animal's failure to cross Fall River Road and reach Sheep Lakes. We conclude that human and road-related disturbance at Sheep Lakes negatively affected bighorn use of the mineral site. Because Sheep Lakes may be important for bighorn sheep, especially for lamb production and survival, the negative influence of disturbance may compromise health and productivity of the Mummy Range bighorn sheep.

  1. Laramide basin CSI: Comprehensive stratigraphic investigations of Paleogene sediments in the Colorado Headwaters Basin, north-central Colorado

    USGS Publications Warehouse

    Dechesne, Marieke; Cole, James Channing; Trexler, James H.; Cashman, Patricia; Peterson, Christopher D

    2013-01-01

    The Paleogene sedimentary deposits of the Colorado Headwaters Basin provide a detailed proxy record of regional deformation and basin subsidence during the Laramide orogeny in north-central Colorado and southern Wyoming. This field trip presents extensive evidence from sedimentology, stratigraphy, structure, palynology, and isotope geochronology that shows a complex history that is markedly different from other Laramide synorogenic basins in the vicinity.We show that the basin area was deformed by faulting and folding before, during, and after deposition of the Paleogene rocks. Internal unconformities have been identified that further reflect the interaction of deformation, subsidence, and sedimentation. Uplift of Proterozoic basement blocks that make up the surrounding mountain ranges today occurred late in basin history. Evidence is given to reinterpret the Independence Mountain uplift as the result of significant normal faulting (not thrusting), probably in middle Tertiary time.While the Denver and Cheyenne Basins to the east were subsiding and accumulating sediment during Late Cretaceous time, the Colorado Headwaters Basin region was experiencing vertical uplift and erosion. At least 1200 m of the upper part of the marine Upper Cretaceous Pierre Shale was regionally removed, along with Fox Hills Sandstone shoreline deposits of the receding Interior Seaway as well as any Laramie Formation–type continental deposits. Subsidence did not begin in the Colorado Headwaters Basin until after 60.5 Ma, when coarse, chaotic, debris-flow deposits of the Paleocene Windy Gap Volcanic Member of the Middle Park Formation began to accumulate along the southern basin margin. These volcaniclastic conglomerate deposits were derived from local, mafic-alkalic volcanic sources (and transitory deposits in the drainage basin), and were rapidly transported into a deep lake system by sediment gravity currents. The southern part of the basin subsided rapidly (roughly 750–1000 m

  2. Jurassic Lake T'oo'dichi': a large alkaline, saline lake, Morrison Formation, eastern Colorado Plateau

    USGS Publications Warehouse

    Turner, C.E.; Fishman, N.S.

    1991-01-01

    Recognition of alkaline, saline-lake deposits in the Morrison Formation significantly alters interpretations of depositional environments of this formation, and it also has important implications for paleoclimatic interpretation. Late Jurassic climate was apparently much more arid than had previously been thought. In fact, sedimentologic evidence suggests that the lake basin was typically dry for extended periods and enjoyed only brief wet intervals. This conclusion has important consequences for environmental interpretation of the habitat that was favorable for large herbivorous dinosaurs, which thrived in the Late Jurassic. -from Authors

  3. View of Lake Mead and Las Vegas, Nevada area from Sklyab

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A vertical view of the Lake Mead and Las Vegas, Nevada area as photographed from Earth orbit by one of the six lenses of the Itek-furnished S190-A Multispectral Photographic Facility Experiment aboard the Skylab space station. Lake Mead is water of the Colorado River impounded by Hoover Dam. Most of the land in the picture is Nevada, however, a part of the northwest corner of Arizona can be seen.

  4. Mass loading of selected major and trace elements in Lake Fork Creek near Leadville, Colorado, September-October 2001

    USGS Publications Warehouse

    Walton-Day, Katherine; Flynn, Jennifer L.; Kimball, Briant A.; Runkel, Robert L.

    2005-01-01

    load to the stream were the parts of the study reach containing inflow from the tribu-taries Halfmoon Creek (calcium) and Willow Creek (sulfate). The Arkansas River and its tributaries upstream from Lake Fork Creek were the source of most of the calcium (70 percent), sulfate (82 percent), manganese (77 percent), lead (78 percent), and zinc (95 percent) loads in the Arkansas River downstream from the Lake Fork confluence. In contrast, Lake Fork Creek was the major source of aluminum (68 percent), copper (65 percent), and iron (87 percent) loads to the Arkansas River downstream from the confluence. Attenuation was not important for calcium, sulfate, or iron. However, other metals loads were reduced up to 81 percent over the study reach (aluminum, 25 percent; copper, 20 percent; manganese, 81 percent; lead, 30 percent; zinc, 72 percent). Metal attenuation in the stream occurred primarily in three locations (1) the irrigation diversion ditch; (2) the beaver pond complex extending from upstream from the Colorado Gulch inflow to just downstream from that inflow; and (3) the stream reach that included the inflow from Willow Creek. The most likely attenuation mechanism is precipitation of metal oxides and hydroxides (primarily manganese), and sorption or coprecipitation of trace elements with the precipitating phase. A mass-balance calculation indicated that the wetland between the Dinero Tunnel and Lake Fork Creek removed iron, had little effect on zinc mass load, and was a source for, or was releasing, aluminum and manganese. In contrast, the wetland that occurred between the Siwatch Tunnel and Lake Fork Creek removed aluminum, iron, manganese, and zinc from the tunnel drainage before it entered the creek. Inflow from the National Fish Hatchery increased dissolved organic carbon concentrations in Lake Fork Creek and slightly changed the composition of the dissolved organic carbon. However, dissolved organic carbon loads increased in the stream reach downs

  5. Geological and Geographical Atlas of Colorado and portions of adjacent territory

    USGS Publications Warehouse

    Hayden, Ferdinand Vandeveer; Bien, Julius

    1881-01-01

    Sheets I-IV are triangulations, drainage, land classification, and geologic maps of Colorado west of longitude 102°, on the scale of 12 miles to the inch. Sheets V-XVI are topographic (contour) and geologic maps of Colorado and adjacent States, between meridians 104° 30' and 109° 30' and parallels 36° 45' and 40° 30', on the scale of 4 miles to the inch. Sheets XVII and XVIII contain three geologic sections across the State, west of the longitude 104° 30'. Sheets XIX and XX are panoramic views of the Pikes Peak group, Sawatch Range, central portion of West Elk Mountains, Twin Lakes, southwestern border of the Mesa Verde, San Juan Mountains, and La Plata Mountains.

  6. Geological and Geographical Atlas of Colorado and portions of adjacent territory

    USGS Publications Warehouse

    Hayden, Ferdinand Vandeveer; Bien, Julius

    1877-01-01

    Sheets I-IV are triangulations, drainage, land classification, and geologic maps of Colorado west of longitude 102°, on the scale of 12 miles to the inch. Sheets V-XVI are topographic (contour) and geologic maps of Colorado and adjacent States, between meridians 104° 30' and 109° 30' and parallels 36° 45' and 40° 30', on the scale of 4 miles to the inch. Sheets XVII and XVIII contain three geologic sections across the State, west of the longitude 104° 30'. Sheets XIX and XX are panoramic views of the Pikes Peak group, Sawatch Range, central portion of West Elk Mountains, Twin Lakes, southwestern border of the Mesa Verde, San Juan Mountains, and La Plata Mountains.

  7. Evidence for a marine incursion along the lower Colorado River corridor

    USGS Publications Warehouse

    McDougall, Kristin; Martínez, Adriana Yanet Miranda

    2014-01-01

    Foraminiferal assemblages in the stratigraphically lower part of the Bouse Formation in the Blythe Basin indicate marine conditions whereas assemblages in the upper part of the Bouse Formation indicate lacustrine conditions and suggest the presence of a saline lake. Benthic foraminiferal assemblages in the lower part of the Bouse Formation are similar to lagoonal and inner neritic biofacies of the modern Gulf of California. Evidence suggesting a change from marine to lacustrine conditions includes the highest occurrence of planktic foraminifers at an elevation of 123 m asl, the change from low diversity to monospecific foraminiferal assemblages composed only of Ammonia beccarii (between 110 to126 m asl), an increase in abundance of A. beccarii specimens (above ~110 m asl), increased number of deformed tests (above ~123 m asl), first appearance of Chara (at ~85 m asl), lowest occurrence of reworked Cretaceous coccoliths (at ~110 m), a decrease in strontium isotopic values (between 70-120 m), and δ18O and δ13C values similar to sea water (between 70-100 m asl). Planktic foraminifers indicate a late Miocene age between 8.10 and 5.3 Ma for the oldest part of the Bouse Formation in the southern part of the Blythe Basin. Benthic and planktic foraminifers correlate with other late Miocene sections and suggest that the basal Bouse Formation in the Blythe Basin was deposited at the northern end of the proto-Gulf of California. After the marine connection was restricted or eliminated, the Colorado River flowed into the Blythe Basin forming a saline lake. This lake supported a monospecific foraminiferal assemblage of A. beccarii until the lake spilled into the Salton Trough and the Colorado River became a through-flowing river.

  8. Flood hydrology and dam-breach hydraulic analyses of five reservoirs in Colorado

    USGS Publications Warehouse

    Stevens, Michael R.; Hoogestraat, Galen K.

    2013-01-01

    The U.S. Department of Agriculture Forest Service has identified hazard concerns for areas downstream from five Colorado dams on Forest Service land. In 2009, the U.S. Geological Survey, in cooperation with the Forest Service, initiated a flood hydrology analysis to estimate the areal extent of potential downstream flood inundation and hazard to downstream life, property, and infrastructure if dam breach occurs. Readily available information was used for dam-breach assessments of five small Colorado reservoirs (Balman Reservoir, Crystal Lake, Manitou Park Lake, McGinnis Lake, and Million Reservoir) that are impounded by an earthen dam, and no new data were collected for hydraulic modeling. For each reservoir, two dam-breach scenarios were modeled: (1) the dam is overtopped but does not fail (break), and (2) the dam is overtopped and dam-break occurs. The dam-breach scenarios were modeled in response to the 100-year recurrence, 500-year recurrence, and the probable maximum precipitation, 24-hour duration rainstorms to predict downstream flooding. For each dam-breach and storm scenario, a flood inundation map was constructed to estimate the extent of flooding in areas of concern downstream from each dam. Simulation results of the dam-break scenarios were used to determine the hazard classification of the dam structure (high, significant, or low), which is primarily based on the potential for loss of life and property damage resulting from the predicted downstream flooding.

  9. Retention of Ancestral Genetic Variation Across Life-Stages of an Endangered, Long-Lived Iteroparous Fish.

    PubMed

    Carson, Evan W; Turner, Thomas F; Saltzgiver, Melody J; Adams, Deborah; Kesner, Brian R; Marsh, Paul C; Pilger, Tyler J; Dowling, Thomas E

    2016-11-01

    As with many endangered, long-lived iteroparous fishes, survival of razorback sucker depends on a management strategy that circumvents recruitment failure that results from predation by non-native fishes. In Lake Mohave, AZ-NV, management of razorback sucker centers on capture of larvae spawned in the lake, rearing them in off-channel habitats, and subsequent release ("repatriation") to the lake when adults are sufficiently large to resist predation. The effects of this strategy on genetic diversity, however, remained uncertain. After correction for differences in sample size among groups, metrics of mitochondrial DNA (mtDNA; number of haplotypes, N H , and haplotype diversity, H D ) and microsatellite (number of alleles, N A , and expected heterozygosity, H E ) diversity did not differ significantly between annual samples of repatriated adults and larval year-classes or among pooled samples of repatriated adults, larvae, and wild fish. These findings indicate that the current management program thus far maintained historical genetic variation of razorback sucker in the lake. Because effective population size, N e , is closely tied to the small census population size (N c = ~1500-3000) of razorback sucker in Lake Mohave, this population will remain at risk from genetic, as well as demographic risk of extinction unless N c is increased substantially. © The American Genetic Association 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Dissolved-solids contribution to the Colorado River from public lands in southeastern Nevada, through September 1993

    USGS Publications Warehouse

    Westenburg, C.L.

    1995-01-01

    The Bureau of Land Management administers about 9,300 square miles of public lands in southeastern Nevada that are part of the Colorado River Basin. The U.S. Geological Survey, in cooperation with the Bureau of Land Management, began a 5-year program in October 1988 to assess the contribution of dissolved solids to the fiver from those lands. About 6,200 square miles of public lands are in the Muddy River subbasin in Nevada. The estimated average dissolved-solids load contributed to the Colorado River from those lands was 28,000 tons per year from October 1988 through September 1993. Subsurface flow contributed about 86 percent (24,000 tons per year) of that load. About 730 square miles of public lands in the Las Vegas Wash subbasin contribute dissolved-solids load to the Colorado River. (About 120 square miles of public lands do not contribute to the river.) The estimated average dissolved-solids load contributed to the river from those lands was about 1,300 tons per year from October 1988 through September 1993. Subsurface flow contributed almost all of that load. About 1,100 square miles of public lands are in the Virgin River subbasin in Nevada. The estimated average dissolved- solids load contributed to the Colorado River from Nevada public lands in the subbasin was 8,700 tons per year. Subsurface flow contributed almost the entire load. About 1,200 square miles of Nevada public lands are in ephemeral tributaries that drain direcfly to the Colorado River or its impoundments (Lake Mead and Lake Mobave). The estimated average dissolved-solids load contributed to the river from those lands was 50 tons per year from surface runoff; however, the dissolved-solids load contributed by subsurface flow was not estimated. From October 1992 to September 1993, the Colorado River carried about 6,600,000 tons of dissolved solids past a streamflow gaging station 0.3 mile downstream from Hoover Dam. In contrast, surface runoff and subsurface flow contribute an estimated

  11. Passive microwave studies of frozen lakes

    NASA Technical Reports Server (NTRS)

    Hall, D. K.; Foster, J. L.; Rango, A.; Chang, A. T. C.

    1978-01-01

    Lakes of various sizes, depths and ice thicknesses in Alaska, Utah and Colorado were overflown with passive microwave sensors providing observations at several wavelengths. A layer model is used to calculate the microwave brightness temperature, T sub B (a function of the emissivity and physical temperatures of the object), of snowcovered ice underlain with water. Calculated T sub B's are comparable to measured T sub B's. At short wavelengths, e.g., 0.8 cm, T sub B data provide information on the near surface properties of ice covered lakes where the long wavelength, 21.0 cm, observations sense the entire thickness of ice including underlying water. Additionally, T sub B is found to increase with ice thickness. 1.55 cm observations on Chandalar Lake in Alaska show a T sub B increase of 38 K with an approximate 124 cm increase in ice thickness.

  12. Ecology of playa lakes

    USGS Publications Warehouse

    Haukos, David A.; Smith, Loren M.

    1992-01-01

    Between 25,000 and 30,000 playa lakes are in the playa lakes region of the southern high plains (Fig. 1). Most playas are in west Texas (about 20,000), and fewer, in New Mexico, Oklahoma, Kansas, and Colorado. The playa lakes region is one of the most intensively cultivated areas of North America. Dominant crops range from cotton in southern areas to cereal grains in the north. Therefore, most of the native short-grass prairie is gone, replaced by crops and, recently, grasses of the Conservation Reserve Program. Playas are the predominant wetlands and major wildlife habitat of the region.More than 115 bird species, including 20 species of waterfowl, and 10 mammal species have been documented in playas. Waterfowl nest in the area, producing up to 250,000 ducklings in wetter years. Dominant breeding and nesting species are mallards and blue-winged teals. During the very protracted breeding season, birds hatch from April through August. Several million shorebirds and waterfowl migrate through the area each spring and fall. More than 400,000 sandhill cranes migrate through and winter in the region, concentrating primarily on the larger saline lakes in the southern portion of the playa lakes region.The primary importance of the playa lakes region to waterfowl is as a wintering area. Wintering waterfowl populations in the playa lakes region range from 1 to 3 million birds, depending on fall precipitation patterns that determine the number of flooded playas. The most common wintering ducks are mallards, northern pintails, green-winged teals, and American wigeons. About 500,000 Canada geese and 100,000 lesser snow geese winter in the playa lakes region, and numbers of geese have increased annually since the early 1980’s. This chapter describes the physiography and ecology of playa lakes and their attributes that benefit waterfowl.

  13. Origin and microfossils of the oil shale of the Green River formation of Colorado and Utah

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bradley, W.H.

    1931-01-01

    The Green River formation of Colorado and Utah is a series of lakebeds of middle Eocene age that occupy two broad, shallow, simple, structural basins--the Piceance Creek basin in northwestern Colorado and the Uinta basin in northeastern Utah. The ancient lakes served as a basin for the accumulation of tremendous quantities of aquatic organisms. The predominance of microscopic fresh-water algae and protozoa over the remains of land plants, pollens and spores suggests that the greater part of the organic matter was derived from microorganisms that grew in the lakes. The pollens and spores were carried into the lakes by wind.more » Fish, mollusks, crustaceans, and aquatic insect larvae were also plentiful; and turtles, crocodiles, birds, small camels, and insects may have contributed to the organic matter. The ancient lakes apparently were shallow and had a large area, compared with depth. The abundance of organisms and the decaying organic matter produced a strongly reducing environment. Mechanical and chemical action, such as the mastication and digestion of the organic material by bottom-living organisms, caused disintegration of the original organic matter. When the residue was reduced to a gelatinous condition, it apparently resisted further bacterial decay, and other organisms accidently entombed in the gel were protected from disintegration. An accumulation of inorganic material occurred simultaneously with the disintegration of the organic ooze, and the entire mass became lithified. After most of the oil shale was deposited, the lake reverted nearly to the conditions that prevailed during its early stage, when the marlstone and low-grade oil shale of the basal member were formed. The streams in the vicinity of the lake were rejuvenated and carried great quantities of medium- to coarse-grained sand into the basin and formed a thick layer over the lakebeds.« less

  14. Microwave Observations of Snow-Covered Freshwater Lake Ice obtained during the Great Lakes Winter EXperiment (GLAWEX), 2017

    NASA Astrophysics Data System (ADS)

    Gunn, G. E.; Hall, D. K.; Nghiem, S. V.

    2017-12-01

    Studies observing lake ice using active microwave acquisitions suggest that the dominant scattering mechanism in ice is caused by double-bounce of the signal off vertical tubular bubble inclusions. Recent polarimetric SAR observations and target decomposition algorithms indicate single-bounce interactions may be the dominant source of returns, and in the absence of field observations, has been hypothesized to be the result of roughness at the ice-water interface on the order of incident wavelengths. This study presents in-situ physical observations of snow-covered lake ice in western Michigan and Wisconsin acquired during the Great Lakes Winter EXperiment in 2017 (GLAWEX'17). In conjunction with NASA's SnowEx airborne snow campaign in Colorado (http://snow.nasa.gov), C- (Sentinel-1, RADARSAT-2) and X-band (TerraSAR-X) synthetic aperture radar (SAR) observations were acquired coincidently to surface physical snow and ice observations. Small/large scale roughness features at the ice-water interface are quantified through auger transects and used as an input variable in lake ice backscatter models to assess the relative contributions from different scattering mechanisms.

  15. A Dreissena Risk Assessment for the Colorado River Ecosystem

    USGS Publications Warehouse

    Kennedy, Theodore A.

    2007-01-01

    Executive Summary Nonnative zebra and quagga mussels (Dreissena polymorpha and Dreissena bugensis, respectively; see photo above) were accidentally introduced to the Great Lakes in the 1980s and subsequently spread to watersheds of the Eastern United States (Strayer and others, 1999). The introduction of Dreissena mussels has been economically costly and has had large and far-reaching ecological impacts on these systems. Quagga mussels were found in Lakes Mead and Havasu in January 2007. Given the likelihood that quagga mussels and, eventually, zebra mussels will be introduced to Lake Powell and the Colorado River at Lees Ferry, it is important to assess the risks that introduction of Dreissena mussels pose to the Colorado River ecosystem (here defined as the segment of river from just below Glen Canyon Dam to Diamond Creek; hereafter CRE). In this report, I assess three different types of risks associated with Dreissena and the CRE: (1) the risk that Dreissena will establish at high densities in the CRE, (2) the risk of ecological impacts should Dreissena establish at high densities in the CRE or in Lake Powell, and (3) the risk that Dreissena will be introduced to tributaries of the CRE. The risk of Dreissena establishing within the CRE is low, except for the Lees Ferry tailwater reach where the risk appears high. Dreissena are unlikely to establish at high densities within the CRE or its tributaries because of high suspended sediment, high ratios of suspended inorganic:organic material, and high water velocities, all of which interfere with the ability of Dreissena to effectively filter feed. The rapids of Grand Canyon may represent a large source of mortality to larval Dreissena, which would limit their ability to disperse and colonize downstream reaches of the CRE. In contrast, conditions within the Lees Ferry tailwater generally appear suitable for Dreissena establishment, with the exception of high average water velocity. If Dreissena establish within the

  16. Validation of MIPAS IMK-IAA Temperature, Water Vapor, and Ozone Profiles with MOHAVE-2009 Campaign Measurements

    NASA Technical Reports Server (NTRS)

    Stiller, Gabrielle; Kiefer, M.; Eckert, E.; von Clarmann, T.; Kellmann, S.; Garcia-Comas, M.; Funke, B.; Leblanc, T.; Fetzer, E.; Froidevaux, L.; hide

    2012-01-01

    MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK) and CSIC, Instituto de Astrofisica de Andalucia (IAA) and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infrared (FTIR) spectrometers. For MIPAS temperatures (version V4O_T_204), no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203) is well within 10% of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40% around 10 km (or 5 km below the tropopause), but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202) has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution. No further

  17. 78 FR 73886 - Atmel Corporation, Colorado Springs, Colorado; Amended Certification Regarding Eligibility To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-09

    ..., Colorado Springs, Colorado; Amended Certification Regarding Eligibility To Apply for Worker Adjustment..., 2013, applicable to workers of Atmel Corporation, Colorado Springs, Colorado. The Department's notice..., Colorado Springs, Colorado were engaged in activities related to production of semiconductor wafers and...

  18. Colorado River Floods, Droughts, and Shrimp Fishing in the Upper Gulf of California, Mexico

    NASA Astrophysics Data System (ADS)

    All, John D.

    2006-01-01

    Accurate procedures that measure hydrologic variability would have great value for evaluating ecosystem impacts of upstream water use in the Colorado River Basin. Many local extractive income-based stakeholders rely directly or indirectly on ecosystem health and are adversely affected when the river does not flow. This study focuses on the impact of little or no Colorado River flow on the Mexican shrimp industry. Although there have been complaints that U.S. diversions of Colorado River flow have greatly impaired the shrimp fishery, this research demonstrates that freshwater rarely reaches the Gulf even during times of flooding, and that other factors such as overfishing may influence the instability of shrimp populations. Advanced very-high-resolution radiometer (AVHRR) satellite imagery was used to assess water volumes diverted away from the channel of the Colorado River and ultimately the Gulf of California during flooding periods. Analysis of data demonstrated that little freshwater actually reaches the Gulf even during floods because of its diversion into a large dry lake bed basin known as Laguna Salada. Fuller use of the Colorado River throughout its entire course to the sea is possible and could benefit a large cohort of users without catastrophic habitat destruction in delta ecosystems. Reconstruction of a natural earthen berm, as proposed by Ducks Unlimited, would maximize the use of floodwaters for ecosystem benefits. These findings have profound implications for local economic activities dependent on hydrologic resources in the Colorado River Delta and Upper Gulf.

  19. Colorado river floods, droughts, and shrimp fishing in the upper gulf of California, Mexico.

    PubMed

    All, John D

    2006-01-01

    Accurate procedures that measure hydrologic variability would have great value for evaluating ecosystem impacts of upstream water use in the Colorado River Basin. Many local extractive income-based stakeholders rely directly or indirectly on ecosystem health and are adversely affected when the river does not flow. This study focuses on the impact of little or no Colorado River flow on the Mexican shrimp industry. Although there have been complaints that U.S. diversions of Colorado River flow have greatly impaired the shrimp fishery, this research demonstrates that freshwater rarely reaches the Gulf even during times of flooding, and that other factors such as overfishing may influence the instability of shrimp populations. Advanced very-high-resolution radiometer (AVHRR) satellite imagery was used to assess water volumes diverted away from the channel of the Colorado River and ultimately the Gulf of California during flooding periods. Analysis of data demonstrated that little freshwater actually reaches the Gulf even during floods because of its diversion into a large dry lake bed basin known as Laguna Salada. Fuller use of the Colorado River throughout its entire course to the sea is possible and could benefit a large cohort of users without catastrophic habitat destruction in delta ecosystems. Reconstruction of a natural earthen berm, as proposed by Ducks Unlimited, would maximize the use of floodwaters for ecosystem benefits. These findings have profound implications for local economic activities dependent on hydrologic resources in the Colorado River Delta and Upper Gulf.

  20. Geologic map of the Dillon quadrangle, Summit and Grand Counties, Colorado

    USGS Publications Warehouse

    Kellogg, Karl S.

    2002-01-01

    New 1:24,000-scale geologic mapping along the Interstate-70 urban corridor in western Colorado, in support of the USGS Central Region State/USGS Cooperative Geologic Mapping Project, is contributing to a more complete understanding of the stratigraphy, structure, tectonic evolution, and hazard potential of this rapidly developing region. The 1:24,000-scale Dillon quadrangle is near the headwaters of the Blue River and straddles features of the Blue River graben (Kellogg, 1999), part of the northernmost reaches of the Rio Grande rift, a major late Oligocene to recent zone of extension that extends from Colorado to Mexico. The Williams Range thrust fault, the western structural margin of the Colorado Front Range, cuts through the center of the quadrangle, although is mostly covered by surficial deposits. The oldest rocks in the quadrangle underlie the Williams Fork Mountains and the ridge immediately east of South Fork Middle Fork River, and include biotite-sillimanite schist and gneiss, amphibolite, and migmatite that are intruded by granite inferred to be part of the 1,667-1,750 Ma Routt Plutonic Suite (Tweto, 1987). The oldest exposed sedimentary unit is the Upper Jurassic Morrison Formation, but Pennsylvanian Maroon Formation, a sequence of red sandstone, conglomerate, and interbedded shale, underlies the southern part of the quadrangle. The thickest sequence of sedimentary rocks is Cretaceous in age and includes at least 500 m of the Upper Cretaceous Pierre Shale. Surficial deposits include (1) an old, deeply dissected landslide deposit, possibly as old as Pliocene, on the west flank of the Williams Fork Mountains, (2) deeply weathered, very coarse gravel deposits underlying a mesa in the southwest part of the quadrangle (the Mesa Cortina subdivision. The gravels are gold bearing and were mined by hydraulic methods in the 1800s), (3) moderately to deeply weathered, widespread, bouldery material that is a combination of till of the Bull Lake glaciation, debris

  1. Geologic map of the Dillon quadrangle, Summit and Grand Counties, Colorado

    USGS Publications Warehouse

    Kellogg, Karl S.

    1997-01-01

    New 1:24,000-scale geologic mapping along the Interstate-70 urban corridor in western Colorado, in support of the USGS Central Region State/USGS Cooperative Geologic Mapping Project, is contributing to a more complete understanding of the stratigraphy, structure, tectonic evolution, and hazard potential of this rapidly developing region. The 1:24,000-scale Dillon quadrangle is near the headwaters of the Blue River and straddles features of the Blue River graben (Kellogg, 1999), part of the northernmost reaches of the Rio Grande rift, a major late Oligocene to recent zone of extension that extends from Colorado to Mexico. The Williams Range thrust fault, the western structural margin of the Colorado Front Range, cuts through the center of the quadrangle, although is mostly covered by surficial deposits. The oldest rocks in the quadrangle underlie the Williams Fork Mountains and the ridge immediately east of South Fork Middle Fork River, and include biotite-sillimanite schist and gneiss, amphibolite, and migmatite that are intruded by granite inferred to be part of the 1,667-1,750 Ma Routt Plutonic Suite (Tweto, 1987). The oldest exposed sedimentary unit is the Upper Jurassic Morrison Formation, but Pennsylvanian Maroon Formation, a sequence of red sandstone, conglomerate, and interbedded shale, underlies the southern part of the quadrangle. The thickest sequence of sedimentary rocks is Cretaceous in age and includes at least 500 m of the Upper Cretaceous Pierre Shale. Surficial deposits include (1) an old, deeply dissected landslide deposit, possibly as old as Pliocene, on the west flank of the Williams Fork Mountains, (2) deeply weathered, very coarse gravel deposits underlying a mesa in the southwest part of the quadrangle (the Mesa Cortina subdivision. The gravels are gold bearing and were mined by hydraulic methods in the 1800s), (3) moderately to deeply weathered, widespread, bouldery material that is a combination of till of the Bull Lake glaciation, debris

  2. Organochlorine compounds and current-use pesticides in snow and lake sediment in Rocky Mountain National Park, Colorado, and Glacier National Park, Montana, 2002-03

    USGS Publications Warehouse

    Mast, M. Alisa; Foreman, William T.; Skaates, Serena V.

    2006-01-01

    Organochlorine compounds and current-use pesticides were measured in snow and lake-sediment samples from Rocky Mountain National Park in Colorado and Glacier National Park in Montana to determine their occurrence and distribution in high-elevation aquatic ecosystems. The U.S. Geological Survey, in cooperation with the National Park Service, collected snow samples at eight sites in Rocky Mountain National Park and at eight sites in Glacier National Park during spring of 2002 and 2003 just prior to the start of snowmelt. Surface sediments were collected from 11 lakes in Rocky Mountain National Park and 10 lakes in Glacier National Park during summer months of 2002 and 2003. Samples were analyzed for organochlorine compounds by gas chromatography with electron-capture detection and current-use pesticides by gas chromatography with electron-impact mass spectrometry. A subset of samples was reanalyzed using a third instrumental technique (gas chromatography with electron-capture negative ion mass spectrometry) to verify detected concentrations in the initial analysis and to investigate the presence of additional compounds. For the snow samples, the pesticides most frequently detected were endosulfan, dacthal, and chlorothalonil, all of which are chlorinated pesticides that currently are registered for use in North America. Concentrations of these pesticides in snow were very low, ranging from 0.07 to 2.36 nanograms per liter. Of the historical-use pesticides, hexachlorobenzene, dieldrin, and trans-nonachlor were detected in snow but only in one sample each. Annual deposition rates of dacthal, endosulfan, and chlorothalonil were estimated at 0.7 to 3.0 micrograms per square meter. These estimates are likely biased low because they do not account for pesticide deposition during summer months. For the lake-sediment samples, DDE (p,p'-dichlorodiphenyldichoroethene) and DDD (p,p'-dichlorodiphenyldichoroethane) were the most frequently detected organochlorine compounds. DDE

  3. Paleomagnetic quantification of upper-plate deformation during Miocene detachment faulting in the Mohave Mountains, Arizona

    USGS Publications Warehouse

    Pease, V.; Hillhouse, J.W.; Wells, R.E.

    2005-01-01

    Paleomagnetic data from Miocene (???20 Ma) volcanic rocks and dikes of west central Arizona reveal the tilt history of Proterozoic crystalline rocks in the hanging wall of the Chemehuevi-Whipple Mountains detachment fault. We obtained magnetization data from dikes and flows in two structural blocks encompassing Crossman Peak and Standard Wash in the Mohave Mountains. In the Crossman block the dike swarm records two components of primary magnetization: (1) CNH, a normal polarity, high-unblocking-temperature or high-coercivity component (inclination, I = 48.5??, declination, D = 6.4??), and (2) CRHm, a reversed polarity, high-temperature or high-coercivity component (I = -33.6??, D = 197.5??). Argon age spectra imply that the dikes have not been reheated above 300??C since their emplacement, and a baked-contact test suggests that the magnetization is likely to be Miocene in age. CRHm deviates from the expected direction of the Miocene axial dipole field and is best explained as a result of progressive tilting about the strike of the overlying andesite flows. These data suggest that the Crossman block was tilted 60?? to the southwest prior to intrusion of the vertical dike swarm, and the block continued to tilt during a magnetic field reversal to normal polarity (CNH). Miocene dikes in the Crossman block are roughly coplanar, so the younger dikes with normal polarity magnetization intruded along planes of weakness parallel to the earlier reversed polarity swarm. An alternative explanation involves CNH magnetization being acquired later during hydrothermal alteration associated with the final stages of dike emplacement. In the Standard Wash block, the primary component of magnetization is a dual-polarity, high-temperature or high-coercivity component (SWHl, I = 7.2??,D= 0.7??). To produce agreement between the expected Miocene magnetic direction and the SWH component requires (1) correcting for a 56?? tilt about the strike of flow bedding and (2) removing a

  4. Colorado amethyst.

    USGS Publications Warehouse

    Michalski, T.C.

    1984-01-01

    Of the 20 or so amethyst localities reported in Colorado, four are described in some detail and comments are given on their geology. The Crystal Hill mine, near La Garita, Saguache County, contains rock crystal (long slender prisms with small rhombohedral terminations) and pale lavender amethyst (generally <3 in. in length). The deposit was worked as early as the 1800's as a gold mine and also contains abundant manganese oxides. Amethyst, associated with argentiferous galena, sphalerite and chalcopyrite, occurs in the Amethyst mine, in the Creede district, on West Willow Creek, Mineral County. The specimens here consist of small pale pinkish-purple crystals interlayered with milky quartz, some as banded forms ("sowbelly agate') and as geode-like vugs. Amethyst also occurs in Unaweep Canyon south of Grand Junction in Mesa County. Pale to very dark amethyst occurs as crystals dominated by large rhombohedra and small prisms (approx 1 in. across). At Red Feather Lakes, Larimer County, amethyst crystals are medium to dark purple and have prism and rhombohedral faces nearly equally developed; some are doubly terminated. -R.S.M.

  5. Town Lake bottom sediments : a chronicle of water quality changes in Austin, Texas, 1960-98

    USGS Publications Warehouse

    Van Metre, Peter C.; Mahler, B.J.

    1999-01-01

    Town Lake, the last in the chain of Highland Lakes on the Colorado River, runs through the center of Austin, Texas. On any given day, grebes and coots dot the water, rowers skim alongside, and the sparkle of the sun on the water can be admired from the adjacent hike and bike path and from the windows of nearby office buildings. During the summer months, crowds gather along the shores of Town Lake to watch as many as 1 million Mexican Free-Tail bats emerge from under the Congress Avenue bridge. But below the lazily moving azure water lies a bed of sediment about 1 meter (m) thick?sediment that has been deposited gradually since the reservoir was formed in 1959 and that has been recording changes in water quality since that time. What can this sediment tell us about the history of water quality in the Colorado River? And what does it say about the effects of the rapid urbanization of Austin and the future health of our environment?

  6. Mineral resources of the Mount Tipton Wilderness Study Area, Mohave County, Arizona

    USGS Publications Warehouse

    Greene, Robert C.; Turner, Robert L.; Jachens, Robert C.; Lawson, William A.; Almquist, Carl L.

    1989-01-01

    The Mount Tipton Wilderness Study Area (AZ-020-012/ 042) comprises 33,950 acres in Mohave County, Ariz. At the request of the U.S. Bureau of Land Management, this area was evaluated for identified mineral resources (known) and mineral resource potential (undiscovered). This work was carried out by the U.S. Bureau of Mines and the U.S. Geological Survey in 1984-87. In this report, the area studied is referred to as the "wilderness study area" or simply "the study area." There are no identified mineral resources in the study area. The southernmost part of the study area is adjacent to the Wallapai (Chloride) mining district and has low mineral resource potential for gold, silver, copper, lead, zinc, and molybdenum in hydrothermal veins. This area also has a low mineral resource potential for tungsten in vein deposits and for uranium in vein deposits or pegmatites. In the central part of the wilderness study area, one small area has low mineral resource potential for uranium in vein deposits or pegmatites and another small area has low resource potential for thorium in vein deposits. The entire study area has low resource potential for geothermal energy but no potential for oil or gas resources.

  7. Surface water acidification responses and critical loads of sulfur and nitrogen deposition in Loch Vale watershed, Colorado

    USGS Publications Warehouse

    Sullivan, T.J.; Cosby, B.J.; Tonnessen, K.A.; Clow, D.W.

    2005-01-01

    We evaluated the sensitivity of The Loch, a subalpine lake in Rocky Mountain National Park in Colorado, to acidification in response to increased atmospheric loading of sulfur (S) and nitrogen (N) using the Model of Acidification of Groundwater in Catchments (MAGIC). Lake water acid‐base chemistry was moderately sensitive to changes in both S and N deposition. However, the loads of S deposition that would drive chronic lake water acid neutralizing capacity (ANC) to below 0 or 20 μeq L−1 were estimated to be 11 and 8 kg S ha−1 yr−1, respectively, assuming constant future N deposition at current levels. Comparable loads for N deposition, assuming constant future S deposition, were estimated to be 21 and 12 kg N ha−1 yr−1, respectively. Modeling results for Andrews Creek, an alpine tributary to The Loch, suggested critical loads for surface water acidification that averaged about one third lower. Surface water ANC = 50 μeq L−1 was projected to occur in 50 years in The Loch if S or N deposition increased by a moderate amount (<40%) but could not be achieved in Andrews Creek by reducing either S or N deposition to zero. On the basis of the results of synoptic surveys of lake water chemistry, about one fifth of the wilderness lakes in the Colorado Front Range are more acid‐sensitive than The Loch. This modeling exercise suggests the need for a regional analysis of critical loads for the larger population of acid‐sensitive aquatic resources in order to provide part of the scientific foundation for federally mandated land management decisions.

  8. Long-term, landscape patterns of past fire events in a montane ponderosa pine forest of central Colorado

    Treesearch

    Peter M. Brown; Merrill R. Kaufmann; Wayne D. Shepperd

    1999-01-01

    Parameters of fire regimes, including fire frequency, spatial extent of burned areas, fire severity, and season of fire occurrence, influence vegetation patterns over multiple scales. In this study, centuries-long patterns of fire events in a montane ponderosa pine - Douglas-fir forest landscape surrounding Cheesman Lake in central Colorado were reconstructed from fire...

  9. Middle- and late-Wisconsin paleobotanic and paleoclimatic records from the southern Colorado Plateau, USA

    USGS Publications Warehouse

    Anderson, R. Scott; Betancourt, J.L.; Mead, J.I.; Hevly, R.H.; Adam, D.P.

    2000-01-01

    The Colorado Plateau is a distinct physiographic province in western North America, which presently straddles the transition between summer-wet and summer-dry climatic regimes to the south and northwest, respectively. In addition to climate, the diversity of environments and plant communities on the Colorado Plateau has resulted from extreme topographic diversity. Desert lowlands as low as 360 m elevation are surrounded by forested plateaus, and even higher peaks greater than 3800 m elevation. This environmental diversity provides a unique opportunity to study the history of biotic communities in an arid region of North America. Although the Colorado Plateau harbours numerous potential sites, the paleoecological record of the Plateau is poorly known. Potential deposits for analysis include packrat middens, alluvial and cave sites at lower elevations, and lake, bog and wetland sites at higher elevations. Forty-six sites have been analysed across the nearly 337,000 km2 region, of which 27 contain records that span Marine Oxygen Isotope Stage (IS) 2 data, with IS 3 information coming from only 12 sites. Most IS 2 and 3 sites are clustered along the lowland regions of the Colorado River corridor and the uplands of the Mogollon Rim area. We compiled selected data from long paleoecological records to examine patterns of vegetation and climate change across the southern Colorado Plateau for the middle and late Wisconsin. During the middle Wisconsin, mixed conifers covered middle-elevations presently dominated by ponderosa pine (Pinus ponderosa), and juniper (Juniperus) woodland grew at elevations today covered by blackbrush (Coleogyne) and sagebrush (Artemisia) desert. During the late Wisconsin, boreal conifers, primarily Engelmann spruce (Picea engelmannii), replaced the mixed conifer association. Estimates of mean annual temperatures (MAT) during IS 3 were at least 3-4??C cooler than today, whereas IS 2 MAT estimates are at least 5??C colder. Our investigation of

  10. Comparison of Atmospheric Deposition Among Three Sites In and Near the Flat Tops Wilderness Area, Colorado, 2003-2005

    USGS Publications Warehouse

    Ingersoll, George P.; Campbell, Donald H.; Mast, M. Alisa

    2008-01-01

    Atmospheric deposition was monitored for ammonium, nitrate, and sulfate concentrations and precipitation amounts in the Flat Tops Wilderness Area of northwestern Colorado at Ned Wilson Lake beginning in 1984 to detect changes that might result from future emissions associated with development of oil-shale resources in northwestern Colorado. Renewed monitoring, by the U.S. Geological Survey, in cooperation with Rio Blanco County, to determine the current status of atmospheric deposition has been ongoing since 2003 at Ned Wilson Lake. Two new monitoring sites were located near Ripple Creek Pass near the Flat Tops Wilderness area and about 12 kilometers north of Ned Wilson Lake because access to the area near Ripple Creek Pass is less difficult and less expensive, particularly in winter and spring. The intent of this study was to establish whether the new deposition data being collected near Ripple Creek Pass, near the northern boundary of the Flat Tops Wilderness Area, would be representative of deposition at sensitive sites within the wilderness such as Ned Wilson Lake and to compare more current (2003 through 2005) deposition data with earlier data (1984 through 1991). At Ned Wilson Lake, bulk ammonium and nitrate concentrations collected from 1984 through 1991 were similar to those from 2003 through 2005. However, in the same comparison significant differences in sulfate concentrations were observed, indicating a decrease consistent with other regional findings for similar periods. Comparison of concentrations of constituents at two bulk-deposition sites located at Ned Wilson Lake (NWLB) and near Ripple Creek Pass (RCPB) showed only one significant difference (p = 0.05) with the winter bulk nitrate concentrations for NWLB significantly lower than winter concentrations from RCPB. Another comparison of concentrations of constituents between the bulk deposition site RCPB and a wet deposition site 100 meters away (RCPW) showed no significant differences for

  11. Quality of water of the Colorado River in 1928-1930

    USGS Publications Warehouse

    Howard, C.S.

    1932-01-01

    This report gives the results obtained in the continuation of a study of the Colorado River begun in 1925.1 The analyses represent composites of daily samples collected by the observers at the gaging stations on the Colorado River at Cisco, Utah, and Lees Ferry and Grand Canyon, Ariz.; on the Green River at Green River, Utah; and on the San Juan River near Bluff, Utah. Analyses are given for samples collected about once a month from the Williams River at Planet, Ariz. The Arizona stations are operated under the direction of W. E. Dickinson, district engineer of the Geological Survey at Tucson, Ariz., and the Utah stations under the direction of A. B. Purton, district engineer of the Geological Survey at Salt Lake City, Utah. The average discharges given in Table 3 were calculated from data furnished by these district engineers. Complete discharge . data for this period will be published in the regular series of water-supply papers.

  12. Climate regulates alpine lake ice cover phenology and aquatic ecosystem structure

    USGS Publications Warehouse

    Preston, Daniel L.; Caine, Nel; McKnight, Diane M.; Williams, Mark W.; Hell, Katherina; Miller, Matthew P.; Hart, Sarah J.; Johnson, Pieter T.J.

    2016-01-01

    High-elevation aquatic ecosystems are highly vulnerable to climate change, yet relatively few records are available to characterize shifts in ecosystem structure or their underlying mechanisms. Using a long-term dataset on seven alpine lakes (3126 to 3620 m) in Colorado, USA, we show that ice-off dates have shifted seven days earlier over the past 33 years and that spring weather conditions – especially snowfall – drive yearly variation in ice-off timing. In the most well-studied lake, earlier ice-off associated with increases in water residence times, thermal stratification, ion concentrations, dissolved nitrogen, pH, and chlorophyll-a. Mechanistically, low spring snowfall and warm temperatures reduce summer stream flow (increasing lake residence times) but enhance melting of glacial and permafrost ice (increasing lake solute inputs). The observed links among hydrological, chemical, and biological responses to climate factors highlight the potential for major shifts in the functioning of alpine lakes due to forecasted climate change.

  13. Deglaciation and postglacial timberline in the San Juan Mountains, Colorado

    USGS Publications Warehouse

    Carrara, P.E.; Mode, W.N.; Rubin, M.; Robinson, S.W.

    1984-01-01

    Lake Emma, which no longer exists because of a mining accident, was a tarn in a south-facing cirque near the headwaters of the Animas River in the San Juan Mountains of southwestern Colorado. During the Pinedale glaciation, this area was covered by a large transection glacier centered over the Lake Emma region. Three radiocarbon dates on basal organic sediment from Lake Emma indicate that by ca. 15,000 yr B.P. this glacier, one of the largest in the southern Rocky Mountains, no longer existed. Twenty-two radiocarbon dates on Picea and Abies krummholz fragments in the Lake Emma deposits indicate that from ca. 9600 to 7800 yr B.P., from 6700 to 5600 yr B.P., and at 3100 yr B.P. the krummholz limit was at least 70 m higher than present. These data, in conjunction with Picea:Pinus pollen ratios from both the Lake Emma site and the Hurricane Basin site of J. T. Andrews, P. E. Carrara, F. B. King, and R. Struckenrath (1975, Quaternary Research 5, 173-197) suggest than from ca. 9600 to 3000 yr B.P. timberline in the San Juan Mountains was higher than present. Cooling apparently began ca. 3000 yr B.P. as indicated by decreases in both the percentage of Picea pollen and Picea:Pinus pollen ratios at the Hurricane Basin site (Andrews et al., 1975). Cooling is also suggested by the lack of Picea or Abies fragments younger than 3000 yr B.P. at either the Lake Emma or the Hurricane Basin site. ?? 1984.

  14. Changing Demands from Riparian Evapotranspiration and Free-Water Evaporation in the Lower Colorado River Basin Under Different Climate Scenarios

    NASA Astrophysics Data System (ADS)

    Bunk, D. A.; Piechota, T. C.

    2012-12-01

    Observed and projected trends in riparian evapotranspiration (ET) and free-water evaporation are examined to improve water demand forecasting for use in modeling of lower Colorado River system reservoir operations. While most previous research has focused on the impacts of climate change and climate variability on water supply, the impacts on water demand under changing climate conditions have not been adequately addressed (NRC, 2007 and Reclamation, 2009). Increases in temperatures and changes in precipitation and wind patterns are expected to increase evaporative demands (Bates and others, 2008), potentially increasing free-water evaporation and ET from riparian vegetation; increasing infiltration rates; altering cropping patterns; and changing the temporal and spatial distribution of water deliveries. This study uses observations and projections under changing climate scenarios of hydroclimatic variables, such as temperature, wind, and precipitation, to analyze their impacts on riparian ET and free-water evaporation in the lower Colorado River mainstream downstream of Lake Mead and Hoover Dam. The projected changes in evaporative demands were assessed to determine their impacts on water supply and reservoir operations in the Colorado River basin under changing climate conditions. Based on analysis of observed and projected hydroclimatic data from the Variable Infiltration Capacity (VIC) hydrologic model, mean annual daily temperature in the lower Colorado River mainstream reach has increased by 0.8° Celsius (C) from the 30-year period ending in 1980 to period ending in 2010 and is projected to increase by an additional 1.7° C by 30-year period ending in 2060. Analysis of riparian ET derived from the ASCE Penman-Monteith method (Allen et al., 2005, from Monteith, 1965 and 1981) and Westenburg et al. (2006) and free-water evaporation derived from the Penman combination model in Dingman (2008) indicates that combined evaporative demand in the lower Colorado River

  15. Shifts in lake N: P stoichiometry and nutrient limitation driven by atmospheric nitrogen deposition

    USGS Publications Warehouse

    Elser, J.J.; Andersen, T.; Baron, Jill S.; Bergstrom, A.-K.; Jansson, M.; Kyle, M.; Nydick, K.R.; Steger, L.; Hessen, D.O.

    2009-01-01

    Human activities have more than doubled the amount of nitrogen (N) circulating in the biosphere. One major pathway of this anthropogenic N input into ecosystems has been increased regional deposition from the atmosphere. Here we show that atmospheric N deposition increased the stoichiometric ratio of N and phosphorus (P) in lakes in Norway, Sweden, and Colorado, United States, and, as a result, patterns of ecological nutrient limitation were shifted. Under low N deposition, phytoplankton growth is generally N-limited; however, in high-N deposition lakes, phytoplankton growth is consistently P-limited. Continued anthropogenic amplification of the global N cycle will further alter ecological processes, such as biogeochemical cycling, trophic dynamics, and biological diversity, in the world's lakes, even in lakes far from direct human disturbance.

  16. 76 FR 28071 - Notice of Inventory Completion: Colorado Historical Society (History Colorado), Denver, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-13

    ...: Colorado Historical Society (History Colorado), Denver, CO AGENCY: National Park Service, Interior. ACTION... control of the Colorado Historical Society (History Colorado), Denver, CO. The human remains were removed.... A detailed assessment of the human remains was made by the Colorado Historical Society (History...

  17. 76 FR 17444 - Notice of Inventory Completion: Colorado Historical Society (History Colorado), Denver, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-29

    ...: Colorado Historical Society (History Colorado), Denver, CO AGENCY: National Park Service, Interior. ACTION... control of the Colorado Historical Society (History Colorado), Denver, CO. The human remains were removed... (History Colorado) professional staff in consultation with representatives of the Hopi Tribe of Arizona...

  18. Mineral inclusions in diamonds from the Kelsey Lake Mine, Colorado, USA: Depleted Archean mantle beneath the Proterozoic Yavapai province

    NASA Astrophysics Data System (ADS)

    Schulze, Daniel J.; Coopersmith, Howard G.; Harte, Ben; Pizzolato, Lori-Ann

    2008-03-01

    Thirty-four silicate and oxide inclusions large enough for in situ WDS electron microprobe analysis were exposed by grinding/polishing of 19 diamonds from the Kelsey Lake Mine in the Colorado-Wyoming State Line Kimberlite district. Eighteen olivines, seven Cr-pyropes, four Mg-chromites, and one orthopyroxene in 15 stones belong to the peridotite (P) suite and three garnets and one omphacite in three stones belong to the eclogite (E) suite. The fact that this suite is dominated by the peridotite population is in stark contrast to the other diamond suites studied in the State Line district (Sloan, George Creek), which are overwhelmingly eclogitic. Kelsey Lake olivine inclusions are magnesian (17 of 18 grains in 9 stones are in the range Fo 92.7-93.1), typical of harzburgitic P-suite stones worldwide, but unlike the more Fe-rich (lherzolitic) Sloan olivine suite. Mg-chromites (wt% MgO = 12.8-13.8; wt% Cr 2O 3 = 61.4-66.6) are in the lower MgO range of diamond inclusion chromites worldwide. Seven harzburgitic Cr-pyropes in five stones have moderately low calcium contents (wt% CaO = 3.3-4.3) but are very Cr-rich (wt% Cr 2O 3 = 9.7-16.7). A few stones have been analyzed by SIMS for carbon isotope composition and nitrogen abundance. One peridotitic stone is apparently homogeneous in carbon isotope composition (δ 13C PDB = -6.2‰) but with variable nitrogen abundance (1296-2550 ppm). Carbon isotopes in eclogitic stones range from "normal" for the upper mantle (δ 13C PDB = -5.5‰) to somewhat low (δ 13C PDB = -10.2‰), with little internal variation in individual stones (maximum difference is 3.6‰). Nitrogen contents (2-779 ppm) are lower than in the peridotitic stone, and are lower in cores than in rims. As, worldwide, harzburgite-suite diamonds have been shown to have formed in Archean time, we suggest that the Kelsey Lake diamond population was derived from a block of Archean lithosphere that, at the time of kimberlite eruption, existed beneath the Proterozoic

  19. Non-native plant invasions in managed and protected ponderosa pine/Douglas-fir forests of the Colorado Front Range

    Treesearch

    Paula J. Fornwalt; Merrill R. Kaufmann; Laurie S. Huckaby; Jason M. Stoker; Thomas J. Stohlgren

    2003-01-01

    We examined patterns of non-native plant diversity in protected and managed ponderosa pine/Douglas-fir forests of the Colorado Front Range. Cheesman Lake, a protected landscape, and Turkey Creek, a managed landscape, appear to have had similar natural disturbance histories prior to European settlement and fire protection during the last century. However, Turkey Creek...

  20. NPDES Permit for Colorado National Monument in Colorado

    EPA Pesticide Factsheets

    Under National Pollutant Discharge Elimination System permit number CO0034975, the National Park Service is directed to have no discharge from the wastewater treatment lagoons at the Colorado National Monument in Mesa County, Colorado.

  1. Perchlorate as a Ground-Water Tracer Along the Lower Colorado River

    NASA Astrophysics Data System (ADS)

    Justet, L.; Lico, M. S.

    2008-12-01

    Anthropogenic perchlorate was first observed in the lower Colorado River (NV and AZ) in 1997. The perchlorate source was traced upstream from Hoover Dam and Lake Mead to Las Vegas Wash. Perchlorate migrated through the local surface- and ground-water systems to the Wash from nearby manufacturing facilities in Henderson, NV, which had been operating since the 1940s. The Nevada Division of Environmental Protection (NDEP) began monitoring perchlorate in the lower Colorado River at Willow Beach, located about 18 km south of the Dam, in 1997. A 3 μg/L reduction was observed at Willow Beach in 2003-2004, coincident with remediation at the Henderson site in 1999-2004. This observed decrease indicates that the effects of remediation rapidly propagated through the surface-water system below the Dam. In July 2008 water samples were collected and analyzed for perchlorate from eight springs along the lower Colorado River below Hoover Dam, from a discharge tunnel in the country rock at Hoover Dam, and from Lake Mead (above and below the thermocline). Lake Mead water collected above the thermocline east of Sentinel Island contained 3.9 μg/L perchlorate, while water below the thermocline contained 1.8 μg/L. Perchlorate concentrations were lower than the 2 to 4 μg/L quantitation limit for the six springs located more than 2 km south of the Dam. Samples from Pupfish Springs, about 0.9 km south of the Dam, contained 6.4-6.8 μg/L perchlorate. Water collected from the discharge tunnel in the Dam contained 8.2 μg/L perchlorate. Perchlorate concentrations observed at Pupfish Springs and the discharge tunnel in the Dam in 2008 are similar to those reported downstream at Willow Beach prior to 2003-2004 by NDEP indicating that the ground water travel time from the Dam to Pupfish Springs is between 4 and 70 years and the maximum flow velocities are between about 13-200 m/y. These rapid velocity estimates suggest that faults and fractures in the area are an important control on

  2. Geologic setting and stratigraphy of the Ziegler Reservoir fossil site, Snowmass Village, Colorado

    USGS Publications Warehouse

    Pigati, Jeff S.; Miller, Ian M.; Johnson, Kirk R.; Honke, Jeffrey S.; Carrara, Paul E.; Muhs, Daniel R.; Skipp, Gary; Bryant, Bruce

    2014-01-01

    The geologic setting of the Ziegler Reservoir fossil site is somewhat unusual – the sediments containing the Pleistocene fossils were deposited in a lake on top of a ridge. The lake basin was formed near the Town of Snowmass Village, Colorado when a glacier flowing down Snowmass Creek Valley became thick enough to overtop a low point in the eastern valley wall and entered the head of Brush Creek Valley. When the glacier retreated at the end of the marine isotope stage (MIS) 6, ~155-130 ka (thousands of years before present), the Brush Creek Valley lobe left behind a moraine that impounded a small alpine lake. The lake was initially ~10 m deep and was highly productive during most of its existence based on the abundant and exquisitely preserved organic material present in the sediments. Over time, the basin slowly filled with (mostly) eolian sediment such that by ~85 ka it contained more of a marsh or wetland than a true lake. Open water conditions returned briefly between ~75 and 55 ka before the impoundment was finally breached to the east, establishing ties with the Brush Creek drainage system and creating an alpine meadow that persisted until historic times.

  3. Surficial Geology of the Floor of Lake Mead (Arizona and Nevada) as Defined by Sidescan-Sonar Imagery, Lake-Floor Topography, and Post-Impoundment Sediment Thickness

    USGS Publications Warehouse

    Twichell, D.C.; Cross, V.A.

    2009-01-01

    Sidescan-sonar imagery collected in Lake Mead during 1999-2001, a period of high lake level, has been used to map the surficial geology of the floor of this large reservoir that formed upon completion of the Hoover Dam in 1935. Four surficial geologic units were identified and mapped: rock exposures and alluvial deposits that existed prior to the formation of the lake and thin post-impoundment sediments ( 1 m) deposited since the lake formed. Exposures of rock are most extensive in the narrow, steep-sided sections of the lake, while alluvial deposits are most extensive on the gentle flanks of the broader basin sections of the lake. Post-impoundment sediment is restricted to the floors of the original river valleys that now lie below lake level. These sediments are thickest in the deltas that form at the mouths of the Colorado River and its tributaries, but cover the entire length of the valley floors of the lake. This sediment distribution is consistent with deposition from turbidity currents. Lake level has dropped more than 30 m between collection of the sidescan imagery and publication of this report. During this time, thick delta deposits have been eroded and redistributed to deeper parts of the lake by turbidity currents. While present-day post-impoundment sediment distribution should be similar to what it was in 2001, the thickness may be greater in some of the deeper parts of the lake now.

  4. Implications of the miocene(?) crooked ridge river of northern arizona for the evolution of the colorado river and grand canyon

    USGS Publications Warehouse

    Lucchitta, Ivo; Holm, Richard F.; Lucchitta, Baerbel K.

    2013-01-01

    The southwesterly course of the probably pre–early Miocene and possibly Oligocene Crooked Ridge River can be traced continuously for 48 km and discontinuously for 91 km in northern Arizona (United States). The course is visible today in inverted relief. Pebbles in the river gravel came from at least as far northeast as the San Juan Mountains (Colorado). The river valley was carved out of easily eroded Jurassic and Cretaceous rocks whose debris overloaded the river with abundant detritus, probably steepening the gradient. After the river became inactive, the regional drainage network was rearranged three times, and the nearby Four Corners region was lowered 1–2 km by erosion. The river provides constraints on the early evolution of the Colorado River and Grand Canyon. Continuation of this river into lakes in Arizona or Utah is unlikely, as is integration through Grand Canyon by lake spillover. The downstream course of the river probably was across the Kaibab arch in a valley roughly coincident with the present eastern Grand Canyon. Beyond this point, the course may have continued to the drainage basin of the Sacramento River, or to the proto–Snake River drainage. Crooked Ridge River was beheaded by the developing San Juan River, which pirated its waters and probably was tributary to a proto–Colorado River, flowing roughly along its present course west of the Monument upwarp.

  5. Chronology of Miocene-Pliocene deposits at Split Mountain Gorge, Southern California: A record of regional tectonics and Colorado River evolution

    USGS Publications Warehouse

    Dorsey, R.J.; Fluette, A.; McDougall, K.; Housen, B.A.; Janecke, S.U.; Axen, G.J.; Shirvell, C.R.

    2007-01-01

    Late Miocene to early Pliocene deposit at Split Mountain Gorge, California, preserve a record of basinal response to changes in regional tectonics, paleogeography, and evolution of the Colorado River. The base of the Elephant Trees Formation, magnetostratigraphically dated as 8.1 ?? 0.4 Ma, provides the earliest well-dated record of extension in the southwestern Salton Trough. The oldest marine sediments are ca. 6.3 Ma. The nearly synchronous timing of marine incursion in the Salton Trough and northern Gulf of California region supports a model for localization of Pacific-North America plate motion in the Gulf ca. 6 Ma. The first appearance of Colorado River sand at the Miocene-Pliocene boundary (5.33 Ma) suggests rapid propagation of the river to the Salton Trough, and supports a lake-spillover hypothesis for initiation of the lower Colorado River. ?? 2007 Geological Society of America.

  6. The potential for retreating alpine glaciers to alter alpine ecosystems in the Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Hall, E.; Baron, J.

    2013-12-01

    Glaciers are retreating at an unprecedented rate. In mid-latitude alpine ecosystems the presence of glaciers and rock glaciers govern rates and ecology of alpine and sub-alpine ecosystems. Changes in the thermal environment due to the loss of isothermal habitat and inputs from glacier melt chemistry are altering alpine ecosystems in unpredictable ways. In particular, glacier may be a source of nitrogen that is altering alpine ecosystem dynamics. Loch Vale Watershed (LVWS) located within Rocky Mountain National Park. LVWS contains a surface glacier (Andrew's glacier) and a rock glacier (Taylor's glacier) at the headwater of each of the two drainages within the watershed. We collected precipitation from a National Atmospheric Deposition Site and surface water from multiple alpine lakes and streams during a particularly high and low snow year in the Colorado Front Range. We also sampled stream and lake sediments at each site to analyze the associated microbial community. Concentrations of nitrate and ammonium, relative abundance of amoA (the gene responsible for a key step in the microbial nitrification pathway), and the dual isotope signal to nitrate all point to snow melt as a key deliverer of nitrogen to ecosystems along the Colorado Front Range. However, late summer surface water chemistry is isotopically similar to the chemistry of glacial ice. This suggests that retreating glacier may be an additional source of N to alpine ecosystems and have the potential to alter microbial community composition, biogeochemical rate processes, and ecosystem function. These dynamics are most likely not unique to the Colorado Front Range and should be globally distributed as glaciers continue to retreat in high altitude ecosystems around the world.

  7. Sensitivity to acidification of subalpine ponds and lakes in north-western Colorado

    USGS Publications Warehouse

    Campbell, D.H.; Muths, E.; Turk, J.T.; Corn, P.S.

    2004-01-01

    Although acidifying deposition in western North America is lower than in many parts of the world, many high-elevation ecosystems there are extremely sensitive to acidification. Previous studies determined that the Mount Zirkel Wilderness Area (MZWA) has the most acidic snowpack and aquatic ecosystems that are among the most sensitive in the region. In this study, spatial and temporal variability of ponds and lakes in and near the MZWA were examined to determine their sensitivity to acidification and the effects of acidic deposition during and after snowmelt. Within the areas identified as sensitive to acidification based on bedrock types, there was substantial variability in acid-neutralizing capacity (ANC), which was related to differences in hydrological flowpaths that control delivery of weathering products to surface waters. Geological and topographic maps were of limited use in predicting acid sensitivity because their spatial resolution was not fine enough to capture the variability of these attributes for lakes and ponds with small catchment areas. Many of the lakes are sensitive to acidification (summer and autumn ANC < 100 µeq L−1), but none of them appeared to be threatened immediately by episodic or chronic acidification. In contrast, 22 ponds had minimum ANC < 30 µeq L−1, indicating that they are extremely sensitive to acidic deposition and could be damaged by episodic acidification, although net acidity (ANC < 0) was not measured in any of the ponds during the study. The lowest measured pH value was 5·4, and pH generally remained less than 6·0 throughout early summer in the most sensitive ponds, indicating that biological effects of acidification are possible at levels of atmospheric deposition that occurred during the study. The aquatic chemistry of lakes was dominated by atmospheric deposition and biogeochemical processes in soils and shallow ground water, whereas the aquatic chemistry of ponds was also affected by organic acids and

  8. School Health Education in Colorado: 1988 Colorado School Health Education Survey.

    ERIC Educational Resources Information Center

    Myers, Mary Lou; Doyen, Mary A., Ed.

    The goals of the 1988 Colorado Health Education Survey were: (1) to document the status of health education in Colorado schools by surveying all school districts in the state as well as by sampling teachers; and (2) to make recommendations based upon study findings available for consideration by the Colorado Department of Education. Part 1, the…

  9. The Role of Trans Tensional Structures and Lake Mead Reservoir in Groundwater Flow in Black Canyon, Lake Mead National Recreation Area, NV-AZ

    NASA Astrophysics Data System (ADS)

    Justet, L.; Beard, S.

    2010-12-01

    Hot springs and seeps discharging into Black Canyon (BC) along the Colorado River in north Colorado River Valley (CRV) support endemic riparian ecosystems in the Lake Mead National Recreation Area. Increases in groundwater development in southern NV and northwestern AZ may impact spring discharge. Sources of spring discharge in BC were evaluated using geochemical methods. Kinematic analysis and geologic mapping of structures associated with BC springs were used to evaluate structural controls on groundwater flow in BC. Geochemical analysis indicates groundwater discharge near Hoover Dam (HD) and along the faulted edge of the Boulder City Pluton is derived from Lake Mead, high δ87Sr Proterozoic or Tertiary crystalline rock and, possibly, Tertiary sedimentary rock. Reducing conditions indicated by 234U/238U and δ34S concentrations suggest the groundwater is confined and/or derived from greater depths while carbon isotopes indicate the groundwater is old. Lighter δD and δO-18, modern tritium concentrations, post-Dam U disequilibrium ages, and occurrence of anthropogenic perchlorate support the presence of a young Lake Mead component. South of the pluton, the Lake Mead component is absent. More oxidizing conditions in this part of BC, indicated by the U and S isotope concentrations, suggest the groundwater is less confined and/or derived from shallower depths compared to groundwater discharging near HD. Older apparent groundwater ages and heavier δD and δO-18 values south of the pluton indicate slower flow paths from a lower elevation or latitude source. Clarifying the nature of groundwater flow in eastern NV, the analyses indicate that hydraulic connection between the regional carbonate aquifer and BC is unlikely. Instead, the data indicate sources of BC springs are derived relatively locally in CRV and, possibly, south Lake Mead Valley. Results of the geologic and kinematic analyses indicate faults that formed from the interaction of E-W extension related to

  10. Colorado transit resource directory

    DOT National Transportation Integrated Search

    2003-11-01

    The Colorado Transit Resource Directory is a joint publication of the Colorado Association of Transit Agencies (CASTA), the Colorado Department of Transportation (CDOT) and the Federal Transit Administration (FTA). It is intended as a resource and ha...

  11. Lake-specific responses to elevated atmospheric nitrogen deposition in the Colorado Rocky Mountains, U.S.A.

    USGS Publications Warehouse

    Nydick, K.R.; LaFrancois, B.M.; Baron, Jill S.; Johnson, B.M.

    2003-01-01

    We explored variability among subalpine lakes sharing very similar climate and atmospheric conditions, but differing in watershed characteristics, hydrology, and food web structure. Special attention was given to nitrogen (N) dynamics because the study area receives some of the highest levels of atmospheric N deposition in the Rocky Mountains. We asked if the effect of regional N deposition would be manifested uniformly among neighboring lakes both in terms of ambient conditions and responses to greater nutrient inputs. Catchment vegetation appeared to be the main determinant of ambient nitrate (NO3), phosphate (PO4), and dissolved organic carbon (DOC) concentrations, although in-lake differences in recycling produced variable and contrasting NH4 levels. Phytoplankton chlorophyll a temporarily responded to early season NO3 peaks in the lakes with rocky watersheds, but chlorophyll means over the ice-free season were remarkably similar among lakes despite differences in both nutrient supply and zooplankton grazing. In most cases, phosphorus was limiting to phytoplankton growth, although the importance of N deficiencies was greater in lakes with forested watersheds and fringing wetlands.

  12. Lake-specific responses to elevated atmospheric nitrogen deposition in the Colorado Rocky Mountains, U.S.A

    USGS Publications Warehouse

    Nydick, K.R.; LaFrancois, B.M.; Baron, Jill S.; Johnson, B.M.

    2003-01-01

    We explored variability among subalpine lakes sharing very similar climate and atmospheric conditions, but differing in watershed characteristics, hydrology, and food web structure. Special attention was given to nitrogen (N) dynamics because the study area receives some of the highest levels of atmospheric N deposition in the Rocky Mountains. We asked if the effect of regional N deposition would be manifested uniformly among neighboring lakes both in terms of ambient conditions and responses to greater nutrient inputs. Catchment vegetation appeared to be the main determinant of ambient nitrate (NO3), phosphate (PO4), and dissolved organic carbon (DOC) concentrations, although in-lake differences in recycling produced variable and contrasting NH4 levels. Phytoplankton chlorophyll atemporarily responded to early season NO3 peaks in the lakes with rocky watersheds, but chlorophyll means over the ice-free season were remarkably similar among lakes despite differences in both nutrient supply and zooplankton grazing. In most cases, phosphorus was limiting to phytoplankton growth, although the importance of N deficiencies was greater in lakes with forested watersheds and fringing wetlands.

  13. Evaluating the mush extraction + multiple magma batch model for the Lake City magmatic system (Colorado, USA) using zircon U/Pb TIMS-TEA

    NASA Astrophysics Data System (ADS)

    Pamukcu, A. S.; Schoene, B.; Deering, C. D.

    2016-12-01

    Volcanic eruptions that involve a wide range of magma types highlight questions on genetic and geometric relationships between magmas in the crust prior to eruption. The Lake City magmatic system (Colorado, USA) is one such example: exposed in the caldera are ignimbrites from the 23 Ma Sunshine Peak Tuff, which range in composition and crystallinity with time (crystal-poor rhyolite to crystal-rich trachyte), and resurgent intrusions of porphyritic syenite, monzonite, and dacite (Hon 1987). Field relations and bulk rock geochemistry suggest the Lake City magmatic system was complex, with magmas of these various types existing concurrently as multiple magma batches, though not necessarily always in contact (Kennedy et al. 2015). Geochemical modeling further suggests that the crystal-poor rhyolites were liquids extracted from a syenitic mush and that the crystal-rich trachytes are remobilized portions of this cumulate. To address the genetic and geometric links between these magmas in more detail, we utilize TIMS-TEA to assess U/Pb zircon geochronology and trace element geochemistry in concert. For each eruptive unit/magma type, zircons were roughly separated into size groupings (small, medium, large), imaged by cathodoluminescence (CL), and analyzed individually by CA-ID-TIMS. Preliminary results indicate that zircons crystallized over a period of 177±31 ky, which is within the range suggested by Ar/Ar geochronology (80-300 ky, Bove et al. 2001). Consistent with the current model for the Lake City system, zircons from the rhyolites and trachytes overlap in age, while those of the dacites are younger. There is no clear relationship between age and CL zoning pattern or crystal size (e.g., small crystals are not always the youngest). We can further address relationships between the rhyolite, trachyte, and syenite using TEA to assess trace elements of the dated zircons. Rhyolite-MELTS models suggest that zircons crystallized in a rhyolitic melt derived from the trachyte

  14. The tertiary lake-basin at Florissant, Colorado, between South and Hayden Parks

    USGS Publications Warehouse

    Scudder, Samuel H.

    1883-01-01

    The following remarks are based upon collections and notes made during a visit to Florissant, in the summer of 1877, in company with Messrs. Arthur Lakes, of Golden, Colo., and F. C. Bowditch, of Boston, Mass. As five days only were spent in the place, most of the time was given up to the collection and care of specimens, so that only a general survey of the locality was possible. Mr. Lakes especially gave himself to the study of the geology of the district, and as he was previously familiar with the structure of the surrounding country, and placed his notes at my disposal, the first part of this paper should be considered our joint production.

  15. Assessment of dissolved-solids loading to the Colorado River in the Paradox Basin between the Dolores River and Gypsum Canyon, Utah

    USGS Publications Warehouse

    Shope, Christopher L.; Gerner, Steven J.

    2014-01-01

    Salinity loads throughout the Colorado River Basin have been a concern over recent decades due to adverse impacts on population, natural resources, and regional economics. With substantial financial resources and various reclamation projects, the salt loading to Lake Powell and associated total dissolved-solids concentrations in the Lower Colorado River Basin have been substantially reduced. The Colorado River between its confluence with the Dolores River and Lake Powell traverses a physiographic area where saline sedimentary formations and evaporite deposits are prevalent. However, the dissolved-solids loading in this area is poorly understood due to the paucity of water-quality data. From 2003 to 2011, the U.S. Geological Survey in cooperation with the U.S. Bureau of Reclamation conducted four synoptic sampling events to quantify the salinity loading throughout the study reach and evaluate the occurrence and impacts of both natural and anthropogenic sources. The results from this study indicate that under late-summer base-flow conditions, dissolved-solids loading in the reach is negligible with the exception of the Green River, and that variations in calculated loads between synoptic sampling events are within measurement and analytical uncertainties. The Green River contributed approximately 22 percent of the Colorado River dissolved-solids load, based on samples collected at the lower end of the study reach. These conclusions are supported by water-quality analyses for chloride and bromide, and the results of analyses for the stable isotopes of oxygen and deuterium. Overall, no significant sources of dissolved-solids loading from tributaries or directly by groundwater discharge, with the exception of the Green River, were identified in the study area.

  16. 78 FR 19296 - Notice of Inventory Completion: History Colorado, formerly Colorado Historical Society, Denver, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ....R50000] Notice of Inventory Completion: History Colorado, formerly Colorado Historical Society, Denver, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: History Colorado, formerly... culturally affiliated with the human remains may contact History Colorado. Disposition of the human remains...

  17. 78 FR 72700 - Notice of Inventory Completion: History Colorado, formerly Colorado Historical Society, Denver, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-03

    ....R50000] Notice of Inventory Completion: History Colorado, formerly Colorado Historical Society, Denver, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: History Colorado has completed... remains should submit a written request to History Colorado. If no additional requestors come forward...

  18. Alpine Warming induced Nitrogen Export from Green Lakes Valley, Colorado Front Range, USA

    NASA Astrophysics Data System (ADS)

    Barnes, R. T.; Williams, M. W.; Parman, J.

    2012-12-01

    Alpine ecosystems are particularly susceptible to disturbance due to their short growing seasons, sparse vegetation and thin soils. Atmospheric nitrogen deposition and warming temperatures currently affect Green Lakes Valley (GLV) within the Colorado Front Range. Research conducted within the alpine links chronic nitrogen inputs to a suite of ecological impacts, resulting in increased nitrate export. According to NADP records at the site, the atmospheric flux of nitrogen has decreased by 0.56 kg ha-1 yr-1 since 2000, due to a decrease in precipitation. Concurrent with this decrease, alpine nitrate yields have continued to increase; by 32% relative to the previous decade (1990-1999). In order to determine the source(s) of the sustained nitrate increases we utilized long term datasets to construct a mass balance model for four stream segments (glacier to subalpine) for nitrogen and weathering product constituents. We also compared geochemical fingerprints of various solute sources (glacial meltwater, thawing permafrost, snow, and stream water) to alpine stream water to determine if sources had changed over time. Long term trends indicate that in addition to increases in nitrate; sulfate, calcium, and silica have also increased over the same period. The geochemical composition of thawing permafrost (as indicated by rock glacial meltwater) suggests it is the source of these weathering products. Mass balance results indicate the high ammonium loads within glacial meltwater are rapidly nitrified, contributing approximately 0.45 kg yr-1 to the NO3- flux within the upper reaches of the watershed. The sustained export of these solutes during dry, summer months is likely facilitated by thawing cryosphere providing hydraulic connectivity late into the growing season. In a neighboring catchment, lacking permafrost and glacial features, there were no long term weathering or nitrogen solute trends; providing further evidence that the changes in alpine chemistry in GLV are likely

  19. NASA Helps Build Colorado Economy

    NASA Image and Video Library

    2010-12-13

    Colorado Association for Manufacturing and Technology (CAMT) CEO Elaine Thorndike, seated left, and NASA Deputy Administrator Lori Garver, seated right, sign an agreement at the Colorado State Capitol in Denver on Monday, Dec. 13, 2010, that created a Technology Acceleration Program and Regional Innovation Cluster for Aerospace and Clean Energy. Looking on from left, Executive Director, Colorado Office of Economic Development and International Trade Don Marostica, Colorado State Representative Su Ryden, Colorado State Senate President Brandon Schaffer, Representative from U.S. Senator Udall's office Jimmy Haugue, NIST/MEP Director Roger Kilmer and Colorado State Governor Bill Ritter. A manufacturing park focused on rapid new product development and production will be developed to assist growing Colorado businesses while promoting the commercialization of technology developed for the space program. Photo Credit: (NASA/Bill Ingalls)

  20. Ploidy race distributions since the Last Glacial Maximum in the North American desert shrub, Larrea tridentata

    USGS Publications Warehouse

    Hunter, K.L.; Betancourt, J.L.; Riddle, B.R.; Van Devender, T. R.; Cole, K.L.; Geoffrey, Spaulding W.

    2000-01-01

    1 A classic biogeographic pattern is the alignment of diploid, tetraploid and hexaploid races of creosote bush (Larrea tridentata) across the Chihuahuan, Sonoran and Mohave Deserts of western North America. We used statistically robust differences in guard cell size of modern plants and fossil leaves from packrat middens to map current and past distributions of these ploidy races since the Last Glacial Maximum (LGM). 2 Glacial/early Holocene (26-10 14C kyr BP or thousands of radiocarbon years before present) populations included diploids along the lower Rio Grande of west Texas, 650 km removed from sympatric diploids and tetraploids in the lower Colorado River Basin of south-eastern California/south-western Arizona. Diploids migrated slowly from lower Rio Grande refugia with expansion into the northern Chihuahuan Desert sites forestalled until after ???4.0 14C kyr BP. Tetraploids expanded from the lower Colorado River Basin into the northern limits of the Sonoran Desert in central Arizona by 6.4 14C kyr BP. Hexaploids appeared by 8.5 14C kyr BP in the lower Colorado River Basin, reaching their northernmost limits (???37??N) in the Mohave Desert between 5.6 and 3.9 14C kyr BP. 3 Modern diploid isolates may have resulted from both vicariant and dispersal events. In central Baja California and the lower Colorado River Basin, modern diploids probably originated from relict populations near glacial refugia. Founder events in the middle and late Holocene established diploid outposts on isolated limestone outcrops in areas of central and southern Arizona dominated by tetraploid populations. 4 Geographic alignment of the three ploidy races along the modern gradient of increasingly drier and hotter summers is clearly a postglacial phenomenon, but evolution of both higher ploidy races must have happened before the Holocene. The exact timing and mechanism of polyploidy evolution in creosote bush remains a matter of conjecture. ?? 2001 Blackwell Science Ltd.

  1. Ploidy race distributions since the Last Glacial Maximum in the North American desert shrub, Larea tridentata

    USGS Publications Warehouse

    Hunter, Kimberly L.; Betancourt, Julio L.; Riddle, Brett R.; Van Devender, Thomas R.; Cole, K.L.; Spaulding, W.G.

    2001-01-01

    1. A classic biogeographic pattern is the alignment of diploid, tetraploid and hexaploid races of creosote bush (Larrea tridentata) across the Chihuahuan, Sonoran and Mohave Deserts of western North America. We used statistically robust differences in guard cell size of modern plants and fossil leaves from packrat middens to map current and past distributions of these ploidy races since the Last Glacial Maximum (LGM). 2 Glacial/early Holocene (26a??10 14C kyr bp or thousands of radiocarbon years before present) populations included diploids along the lower Rio Grande of west Texas, 650 km removed from sympatric diploids and tetraploids in the lower Colorado River Basin of south-eastern California/south-western Arizona. Diploids migrated slowly from lower Rio Grande refugia with expansion into the northern Chihuahuan Desert sites forestalled until after ~4.0 14C kyr bp. Tetraploids expanded from the lower Colorado River Basin into the northern limits of the Sonoran Desert in central Arizona by 6.4 14C kyr bp. Hexaploids appeared by 8.5 14C kyr bp in the lower Colorado River Basin, reaching their northernmost limits (~37A?N) in the Mohave Desert between 5.6 and 3.9 14C kyr bp. 3 Modern diploid isolates may have resulted from both vicariant and dispersal events. In central Baja California and the lower Colorado River Basin, modern diploids probably originated from relict populations near glacial refugia. Founder events in the middle and late Holocene established diploid outposts on isolated limestone outcrops in areas of central and southern Arizona dominated by tetraploid populations. 4 Geographic alignment of the three ploidy races along the modern gradient of increasingly drier and hotter summers is clearly a postglacial phenomenon, but evolution of both higher ploidy races must have happened before the Holocene. The exact timing and mechanism of polyploidy evolution in creosote bush remains a matter of conjecture.

  2. Colorado geology then and now: following the route of the Colorado Scientific Society's 1901 trip through central Colorado

    USGS Publications Warehouse

    Simmons, Beth

    2013-01-01

    In 1901, Charles Van Hise asked Samuel Emmons and Whitman Cross to organize a grand excursion across Colorado as part of the combined meeting of the American Association for the Advancement of Science, GSA, and the Colorado Scientific Society (CSS). This trip replays part of that 10-day excursion across Colorado. Shortened to three days, this trip takes in some of the same sites as the 1901 trip, plus adds others of interest along the route where CSS members are reinventing geological interpretations. The trip will follow the precedent set in 1901; CSS members will serve as “site or stop hosts” in addition to the trip leader and drivers. While walking in the steps of the most famous of our profession we will also see some of the most magnificent scenery of Colorado.

  3. Assessment of multiple sources of anthropogenic and natural chemical inputs to a morphologically complex basin, Lake Mead, USA

    USGS Publications Warehouse

    Rosen, Michael R.; Van Metre, P.C.

    2010-01-01

    Lakes with complex morphologies and with different geologic and land-use characteristics in their sub-watersheds could have large differences in natural and anthropogenic chemical inputs to sub-basins in the lake. Lake Mead in southern Nevada and northern Arizona, USA, is one such lake. To assess variations in chemical histories from 1935 to 1998 for major sub-basins of Lake Mead, four sediment cores were taken from three different parts of the reservoir (two from Las Vegas Bay and one from the Overton Arm and Virgin Basin) and analyzed for major and trace elements, radionuclides, and organic compounds. As expected, anthropogenic contaminant inputs are greatest to Las Vegas Bay reflecting inputs from the Las Vegas urban area, although concentrations are low compared to sediment quality guidelines and to other USA lakes. One exception to this pattern was higher Hg in the Virgin Basin core. The Virgin Basin core is located in the main body of the lake (Colorado River channel) and is influenced by the hydrology of the Colorado River, which changed greatly with completion of Glen Canyon Dam upstream in 1963. Major and trace elements in the core show pronounced shifts in the early 1960s and, in many cases, gradually return to concentrations more typical of pre-1960s by the 1980s and 1990s, after the filling of Lake Powell. The Overton Arm is the sub-basin least effected by anthropogenic contaminant inputs but has a complex 137Cs profile with a series of large peaks and valleys over the middle of the core, possibly reflecting fallout from nuclear tests in the 1950s at the Nevada Test Site. The 137Cs profile suggests a much greater sedimentation rate during testing which we hypothesize results from greatly increased dust fall on the lake and Virgin and Muddy River watersheds. The severe drought in the southwestern USA during the 1950s might also have played a role in variations in sedimentation rate in all of the cores. ?? 2009.

  4. ERTS computer compatible tape data processing and analysis. Appendix 1: The utility of imaging radars for the study of lake ice

    NASA Technical Reports Server (NTRS)

    Polcyn, F. C.; Thomson, F. J.; Porcello, L. J.; Sattinger, I. J.; Malila, W. A.; Wezernak, C. T.; Horvath, R.; Vincent, R. K. (Principal Investigator); Bryan, M. L.

    1972-01-01

    There are no author-identified significant results in this report. Remotely sensed multispectral scanner and return beam vidicon imagery from ERTS-1 is being used for: (1) water depth measurements in the Virgin Islands and Upper Lake Michigan areas; (2) mapping of the Yellowstone National Park; (3) assessment of atmospheric effects in Colorado; (4) lake ice surveillance in Canada and Great Lakes areas; (5) recreational land use in Southeast Michigan; (6) International Field Year on the Great Lakes investigations of Lake Ontario; (7) image enhancement of multispectral scanner data using existing techniques; (8) water quality monitoring of the New York Bight, Tampa Bay, Lake Michigan, Santa Barbara Channel, and Lake Erie; (9) oil pollution detection in the Chesapeake Bay, Gulf of Mexico southwest of New Orleans, and Santa Barbara Channel; and (10) mapping iron compounds in the Wind River Mountains.

  5. A geochronologic framework for the Ziegler Reservoir fossil site, Snowmass Village, Colorado

    USGS Publications Warehouse

    Mahan, Shannon; Gray, Harrison J.; Pigati, Jeffrey S.; Wilson, Jim; Lifton, Nathaniel A.; Paces, James B.; Blaauw, Maarten

    2014-01-01

    The Ziegler Reservoir fossil site near Snowmass Village, Colorado, provides a unique opportunity to reconstruct high-altitude paleoenvironmental conditions in the Rocky Mountains during the last interglacial period. We used four different techniques to establish a chronological framework for the site. Radiocarbon dating of lake organics, bone collagen, and shell carbonate, and in situ cosmogenic 10Be and 26Al ages on a boulder on the crest of a moraine that impounded the lake suggest that the ages of the sediments that hosted the fossils are between ~ 140 ka and > 45 ka. Uranium-series ages of vertebrate remains generally fall within these bounds, but extremely low uranium concentrations and evidence of open-system behavior limit their utility. Optically stimulated luminescence (OSL) ages (n = 18) obtained from fine-grained quartz maintain stratigraphic order, were replicable, and provide reliable ages for the lake sediments. Analysis of the equivalent dose (DE) dispersion of the OSL samples showed that the sediments were fully bleached prior to deposition and low scatter suggests that eolian processes were likely the dominant transport mechanism for fine-grained sediments into the lake. The resulting ages show that the fossil-bearing sediments span the latest part of marine isotope stage (MIS) 6, all of MIS 5 and MIS 4, and the earliest part of MIS 3.

  6. Isopach and isoresource maps for oil shale deposits in the Eocene Green River Formation for the combined Uinta and Piceance Basins, Utah and Colorado

    USGS Publications Warehouse

    Mercier, Tracey J.; Johnson, Ronald C.

    2012-01-01

    The in-place oil shale resources in the Eocene Green River Formation of the Piceance Basin of western Colorado and the Uinta Basin of western Colorado and eastern Utah are estimated at 1.53 trillion barrels and 1.32 trillion barrels, respectively. The oil shale strata were deposited in a single large saline lake, Lake Uinta, that covered both basins and the intervening Douglas Creek arch, an area of comparatively low rates of subsidence throughout the history of Lake Uinta. Although the Green River Formation is largely eroded for about a 20-mile area along the crest of the arch, the oil shale interval is similar in both basins, and 17 out of 18 of the assessed oil shale zones are common to both basins. Assessment maps for these 17 zones are combined so that the overall distribution of oil shale over the entire extent of Lake Uinta can be studied. The combined maps show that throughout most of the history of Lake Uinta, the richest oil shale was deposited in the depocenter in the north-central part of the Piceance Basin and in the northeast corner of the Uinta Basin where it is closest to the Piceance Basin, which is the only area of the Uinta Basin where all of the rich and lean oil shale zones, originally defined in the Piceance Basin, can be identified. Both the oil shale and saline mineral depocenter in the Piceance Basin and the richest oil shale area in the Uinta Basin were in areas with comparatively low rates of subsidence during Lake Uinta time, but both areas had low rates of clastic influx. Limiting clastic influx rather than maximizing subsidence appears to have been the most important factor in producing rich oil shale.

  7. Post-Wildfire Hydrologic Hazards in the Wildland Urban Interface of Colorado and the Western United States

    USGS Publications Warehouse

    Stevens, M.R.; Bossong, C.R.; Rupert, M.G.; Ranalli, A.J.; Cassidy, E.W.; Druliner, A.D.

    2008-01-01

    Following a wildfire, such as the 2002 Missionary Ridge fire, a number of hydrologic hazards may develop that can have an important impact on water resources, businesses, homes, reservoirs, roads, and utilities in the wildland urban interface (areas where homes and commercial developments are interspersed with wildlands) in mountainous areas of the Western United States. This fact sheet describes these hazards and identifies approaches to quantify them, thus enabling land and resource managers to plan for and mitigate the effects of these hazards. The fact sheet has been produced in association with the U.S. Geological Survey (USGS) Fire Science Thrust program and the Colorado Front Range Demonstration Project (CFRDP). The current (2007) focus of the CFRDP is on the Three Lakes watershed in Grand County, Colorado, which has applicability to many similar forested, mountain areas in the Western United States.

  8. New data for Late Pleistocene Pinedale alpine glaciation from southwestern Colorado

    USGS Publications Warehouse

    Benson, L.; Madole, R.; Landis, G.; Gosse, J.

    2005-01-01

    New cosmogenic surface-exposure ages of moraine-crest boulders from southwestern Colorado are compared with published surface-exposure ages of boulders from moraine complexes in north-central Colorado and in west-central (Fremont Lake basin) Wyoming. 10Be data sets from the three areas were scaled to a single 10Be production rate of 5.4 at/g/yr at sea level and high latitude (SLHL), which represents the average 10Be production rate for two high-altitude, mid-latitude sites in the western United States (US) and Austria. Multiple nuclide ages on single boulders indicate that this 10Be production rate yields ages comparable to those calculated with a commonly used 36Cl production scheme. The average age and age range of moraine-crest boulders on terminal moraines at the southwestern Colorado and Wyoming sites are similar, indicating a retreat from their positions ???16.8 36Cl ka (Cosmogenic ages in this paper are labeled 10Be or 36Cl ka or just ka when both 10Be or 36Cl ages are being discussed; radiocarbon ages are labeled 14C ka, calibrated radiocarbon are labeled cal ka, and calendar ages are labeled calendar ka. Errors (??1??) associated with ages are shown in tables. Radiocarbon ages were calibrated using the data of Hughen et al. (Science 303 (2004) 202). This suggests a near-synchronous retreat of Pinedale glaciers across a 470-km latitudinal range in the Middle and Southern Rocky Mountains. Hypothetical corrections for snow shielding and rock-surface erosion shifts the time of retreat to between 17.2 and 17.5 10Be ka at Pinedale, Wyoming, and between 16.3 and 17.3 36Cl ka at Hogback Mountain, Colorado. ?? 2004 Elsevier Ltd. All rights reserved.

  9. Geologic map of Lake Mead and surrounding regions, southern Nevada, southwestern Utah, and northwestern Arizona

    USGS Publications Warehouse

    Felger, Tracey J.; Beard, Sue

    2010-01-01

    Regional stratigraphic units and structural features of the Lake Mead region are presented as a 1:250,000 scale map, and as a Geographic Information System database. The map, which was compiled from existing geologic maps of various scales, depicts geologic units, bedding and foliation attitudes, faults and folds. Units and structural features were generalized to highlight the regional stratigraphic and tectonic aspects of the geology of the Lake Mead region. This map was prepared in support of the papers presented in this volume, Special Paper 463, as well as to facilitate future investigations in the region. Stratigraphic units exposed within the area record 1800 million years of geologic history and include Proterozoic crystalline rocks, Paleozoic and Mesozoic sedimentary rocks, Mesozoic plutonic rocks, Cenozoic volcanic and intrusive rocks, sedimentary rocks and surfi cial deposits. Following passive margin sedimentation in the Paleozoic and Mesozoic, late Mesozoic (Sevier) thrusting and Late Cretaceous and early Tertiary compression produced major folding, reverse faulting, and thrust faulting in the Basin and Range, and resulted in regional uplift and monoclinal folding in the Colorado Plateau. Cenozoic extensional deformation, accompanied by sedimentation and volcanism, resulted in large-magnitude high- and low-angle normal faulting and strike-slip faulting in the Basin and Range; on the Colorado Plateau, extension produced north-trending high-angle normal faults. The latest history includes integration of the Colorado River system, dissection, development of alluvial fans, extensive pediment surfaces, and young faulting.

  10. 2011 Kids Count in Colorado! The Impact of the Great Recession on Colorado's Children

    ERIC Educational Resources Information Center

    Colorado Children's Campaign, 2011

    2011-01-01

    "Kids Count in Colorado!" is an annual publication of the Colorado Children's Campaign, which provides the best available state- and county-level data to measure and track the education, health and general well-being of the state's children. "Kids Count in Colorado!" informs policy debates and community discussions, serving as…

  11. Introduction to paleoenvironments of Bear Lake, Utah and Idaho, and its catchment

    USGS Publications Warehouse

    Rosenbaum, Joseph G.; Kaufman, Darrell S.

    2009-01-01

    In 1996 a group led by the late Kerry Kelts (University of Minnesota) and Robert Thompson (U.S. Geological Survey) acquired three piston cores (BL96-1, -2, and -3) from Bear Lake. The coring arose from their recognition of Bear Lake as a potential repository of long records of paleoenvironmental change. They recognized that the lake is located in an area that is sensitive to changes in regional climate patterns (Dean et al., this volume), that the lake basin is long lived (see Colman, 2006; Kaufman et al., this volume), and that, unlike many lakes in the Great Basin, Bear Lake was never dry during warm dry periods. Bear Lake lies in the northeastern Great Basin to the northeast of Great Salt Lake, just south of the Snake River drainage, and a short distance west of the Green River drainage that makes up part of the Upper Colorado River Basin (Fig. 1). Similarity among the historic Bear Lake and Great Salt Lake hydrographs and flows on the Green River indicates that the hydrology of Bear Lake reflects regional precipitation (Fig. 2). Therefore, paleorecords from Bear Lake are important to understanding past climate for a large region, including the Upper Colorado River Basin, the source of much of the water for the southwestern United States. Initially, paleoenvironmental studies of Bear Lake sediments focused on cores BL96-1, -2, and -3. Additional coring was conducted to elucidate the spatial distribution of sedimentary units and to extend the record back in time. The study was also expanded to include extensive study of the catchment, including the properties of catchment materials and the processes that could potentially affect the delivery of catchment materials to the lake. Cores BL96-1, -2, and -3 were taken with a Kullenburg piston corer along an east–west profile in roughly 50, 40, and 30 m of water, respectively (Table 1, Fig. 3). These three cores, each taken as a single 4- to 5-m-long segment, provide a nearly complete composite section from ca. 26 cal

  12. First Fourteen Years of Lake Mead

    USGS Publications Warehouse

    Thomas, Harold E.

    1954-01-01

    This circular summarizes the results of recent studies of Lake Mead and its environs. Area-capacity tables, prepared on the basis of a hydrographic survey of the lake in 1948-49, show that the capacity of the reservoir was reduced 4.9 percent during the first 14 years after Hoover Dam was completed, but the usable capacity was reduced only 3.2 percent. Practically all of this reduction was caused by accumulation of sediment in the reservoir. Studies of inflow and outflow indicate that the reservoir has a total storage capacity about 12 percent greater than that shown by the area-capacity table, because of 'bank' storage, or ground-water storage in the bottom and sides of the reservoir. Thus the total capacity in 1949 was greater than the quantity shown by the original area-capacity table, even though large quantities of sediment had been deposited in the reservoir during the 14 years. According to computations of the volume and weight of the accumulated sediment, about 2,000 million tons were deposited in the reservoir by the Colorado River in 14 years; this is within 2 percent of the amount calculated from measurements of the suspended sediment carried by the in flowing rivers. It is estimated that the sediment capacity of the reservoir, when filled to the level of the permanent spillway crest, is about 75,000 million tons. The sediment contributed by the Colorado River averages about 45 percent sand and 55 percent silt and clay. If the sediment carried by the river in the years 1926-50 represents the long-term average rate of accumulation in Lake Mead, it will be a century before the sediment at the dam reaches the level of the lowest gates in the intake towers, and more than 4 centuries before the reservoir is filled with sediment to the level of the permanent spillway crest. The rate of sedimentation since the first year of Lake Mead (1935) has been about 20 percent lower, and if that rate continues in the future, the life of the reservoir will be

  13. Review Report for Flood Control and Recreational Development, Little Colorado River at Holbrook, Arizona. Volume 2. Technical Appendix.

    DTIC Science & Technology

    1980-09-01

    led by William C. Allen stayed at this place; while George Lake’s group went approximately 4 mi. downstream and across the river, to establish the...Goodwin, Grenville 1942 The Social Organization of the Western Apache, University Of Chicago Press, Chicago. Gumerman, George J. and S. Alan Skinner 1968...A Synthesis of the Prehistory of the Central Little Colorado Valley, Arizona. American Antiquity, Vol. 33, No. 2. Gumerman, George 1969 Th

  14. 77 FR 15798 - Notice of Intent To Repatriate Cultural Items: The Colorado College, Colorado Springs, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-16

    ... La Poudre, Colorado Springs, CO 80903, telephone (719) 389-6201. SUPPLEMENTARY INFORMATION: Notice is... 201, 14 E. Cache La Poudre, Colorado Springs, Colorado 80903, telephone (719) 389-6201, before April...

  15. 78 FR 30737 - Irish Potatoes Grown in Colorado; Reestablishment of Membership on the Colorado Potato...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ... contains regulatory documents #0;having general applicability and legal effect, most of which are keyed #0... FR] Irish Potatoes Grown in Colorado; Reestablishment of Membership on the Colorado Potato...: This final rule reestablishes the membership on the Colorado Potato Administrative Committee, Area No...

  16. Late Cenozoic Colorado River Incision and Implications for Neogene Uplift of the Colorado Rockies

    NASA Astrophysics Data System (ADS)

    Aslan, A.; Karlstrom, K. E.; Kirby, E.; Heizler, M. T.

    2012-12-01

    Basalt flows and volcanic ashes serve as a datum for calculating post-10 Ma river incision rates in western Colorado. The main picture that emerges from the data is one of regional variability of incision rates, which we hypothesize to reflect differential uplift of the Colorado Rockies during the Neogene. Maximum rates (90-180 m/Ma) and magnitudes (750-1500 m) of river incision are recorded between Grand Mesa and Glenwood Canyon, and in the Flat Tops. Minimum rates (<30 m/Ma) and magnitudes (<250 m) of river incision are associated post-Laramide normal faults within the Browns Park-Sand Wash basin in northwestern Colorado and in Middle Park of north-central Colorado. Differential uplift of the Colorado Rockies during the late Cenozoic can be inferred by comparing incision rates and magnitudes at locations upstream and downstream of knickzones. Along the Colorado River, post-10 Ma incision rates and magnitudes incision remain fairly constant (rates >100 m/Ma; magnitudes >1000 m) from Grand Mesa upstream to Gore Canyon, and then decrease markedly in Middle Park (rates <10 m/Ma; magnitudes <100 m) across the Gore Canyon knickzone. Normal-faulting of ca. 10 Ma deposits in Middle Park shows that incision rate variations partly reflect late Cenozoic faulting. Along the Yampa River, post-10 Ma incision rates and magnitudes are low (rates 15-27 m/Ma; magnitudes < 230 m) immediately upstream of Yampa Canyon, and then increase significantly (rates 96-132 m/Ma; magnitudes ~1250 m) upstream near the headwaters. We interpret this upstream increase in river incision rate and magnitude to reflect Neogene uplift of the Yampa River headwaters relative to its lower reaches. Lastly, differential late Cenozoic uplift of the Colorado Rockies is suggested by differences in the timing of regional exhumation and river incision within different drainage basins. Colorado River incision and regional exhumation occurred between 9.8 and 7.8 Ma. In contrast, Yampa River incision began between

  17. Groundwater Depletion During Drought Threatens Future Water Security of the Colorado River Basin

    NASA Technical Reports Server (NTRS)

    Castle, Stephanie L.; Thomas, Brian F.; Reager, John T.; Rodell, Matthew; Swenson, Sean C.; Famiglietti, James S.

    2014-01-01

    Streamflow of the Colorado River Basin is the most overallocated in the world. Recent assessment indicates that demand for this renewable resource will soon outstrip supply, suggesting that limited groundwater reserves will play an increasingly important role in meeting future water needs. Here we analyze 9 years (December 2004 to November 2013) of observations from the NASA Gravity Recovery and Climate Experiment mission and find that during this period of sustained drought, groundwater accounted for 50.1 cu km of the total 64.8 cu km of freshwater loss. The rapid rate of depletion of groundwater storage (5.6 +/- 0.4 cu km/yr) far exceeded the rate of depletion of Lake Powell and Lake Mead. Results indicate that groundwater may comprise a far greater fraction of Basin water use than previously recognized, in particular during drought, and that its disappearance may threaten the long-term ability to meet future allocations to the seven Basin states.

  18. Groundwater depletion during drought threatens future water security of the Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Castle, Stephanie L.; Thomas, Brian F.; Reager, John T.; Rodell, Matthew; Swenson, Sean C.; Famiglietti, James S.

    2014-08-01

    Streamflow of the Colorado River Basin is the most overallocated in the world. Recent assessment indicates that demand for this renewable resource will soon outstrip supply, suggesting that limited groundwater reserves will play an increasingly important role in meeting future water needs. Here we analyze 9 years (December 2004 to November 2013) of observations from the NASA Gravity Recovery and Climate Experiment mission and find that during this period of sustained drought, groundwater accounted for 50.1 km3 of the total 64.8 km3 of freshwater loss. The rapid rate of depletion of groundwater storage (-5.6 ± 0.4 km3 yr-1) far exceeded the rate of depletion of Lake Powell and Lake Mead. Results indicate that groundwater may comprise a far greater fraction of Basin water use than previously recognized, in particular during drought, and that its disappearance may threaten the long-term ability to meet future allocations to the seven Basin states.

  19. Colorado Water Institute

    Science.gov Websites

    Colorado Water Institute Colorado State University header HomeMission StatementGRAD592NewslettersPublications/ReportsCSU Water ExpertsFunding OpportunitiesScholarshipsSubscribeEmploymentAdvisory BoardStaffContact UsCommentsLinks Water Center Logo Water Resources Archive Office of Engagement Ag Water

  20. 78 FR 9629 - Irish Potatoes Grown in Colorado; Reestablishment of Membership on the Colorado Potato...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-11

    ... Service 7 CFR Part 948 [Doc. No. AMS-FV-12-0044; FV12-948-2 PR] Irish Potatoes Grown in Colorado; Reestablishment of Membership on the Colorado Potato Administrative Committee, Area No. 2 AGENCY: Agricultural... membership on the Colorado Potato Administrative Committee, Area No. 2 (Committee). The Committee locally...

  1. 2008 KidsCount in Colorado!

    ERIC Educational Resources Information Center

    Colorado Children's Campaign, 2008

    2008-01-01

    "KidsCount in Colorado!" is an annual publication of the Colorado Children's Campaign, which provides the best available state- and county-level data to measure and track the education, health and general well-being of the state's children. KidsCount in Colorado! informs policy debates and community discussions, serving as a valuable…

  2. Salinity in the Colorado River in the Grand Valley, western Colorado, 1994-95

    USGS Publications Warehouse

    Butler, David L.; von Guerard, Paul B.

    1996-01-01

    Salinity, or the dissolved-solids concentration, is the measure of salts such as sodium chloride, calcium bicarbonate, and calcium sulfate that are dissolved in water. About one-half of the salinity in the Colorado River Basin is from natural sources (U.S. Department of the Interior, 1995), such as thermal springs in the Glenwood-Dotsero area, located about 90 miles upstream from Grand Junction (fig. 1). Effects of human activities, such as irrigation, reservoir evaporation, and transbasin diversions, have increased the levels of salinity in the Colorado River. High salinity can affect industrial and municipal water users by causing increased water-treatment costs, increased deterioration of plumbing and appliances, increased soap needs, and undesirable taste of drinking water. High salinity also can cause lower crop yields by reducing water and nutrient uptake by plants and can increase agricultural production costs because of higher leaching and drainage requirements. Agricultural losses might occur when salinity reaches about 700?850 milligrams per liter (U.S Department of the Interior, 1994). Figure 1. Irrigated area in the Grand Valley and locations of sampling sites for the 1994?95 salinity study of the Colorado River. The Colorado River is the major source of irrigation water to the Grand Valley (fig. 1) and also is one source of water for the Clifton Water District, which supplies domestic water to part of the eastern Grand Valley. During spring and early summer in 1994, the Colorado River in the Grand Valley had lower than average streamflow. There was concern by water users about the effect of this low streamflow on salinity in the river. In 1994, the U.S. Geological Survey (USGS), in cooperation with the Colorado River Water Conservation District, began a study to evaluate salinity in the Colorado River. This fact sheet describes results of that study. The specific objectives of the fact sheet are to (1) compare salinity in the Colorado River among

  3. Description of water-systems operations in the Arkansas River basin, Colorado

    USGS Publications Warehouse

    Abbott, P.O.

    1985-01-01

    To facilitate a current project modeling the hydrology of the Arkansas River basin in Colorado, a description of the regulation of water in the basin is necessary. The geographic and climatic setting of the Arkansas River basin that necessitates the use, reuse, importation, and storage of water are discussed. The history of water-resource development in the basin, leading to the present complex of water systems, also is discussed. Municipal, irrigation, industrial, and multipurpose water systems are described. System descriptions are illustrated with schematic line drawings, and supplemented with physical data tables for the lakes, tunnels, conduits, and canals in the various systems. Copies of criteria under which certain of the water systems operate, are included. (USGS)

  4. Recovery of perennial vegetation in military target sites in the eastern Mohave Desert, Arizona

    USGS Publications Warehouse

    Steiger, John W.; Webb, Robert H.

    2000-01-01

    The effect of the age of geomorphic surfaces on the recovery of desert vegetation in military target sites was studied in the Mohave and Cerbat Mountains of northwestern Arizona. The target sites were cleared of all vegetation during military exercises in 1942-1943 and have not been subsequently disturbed. The degree of recovery was measured by calculating percentage-similarity (PS) and correlation-coefficient indices on the basis of differences in cover, density, and volume of species growing in and out of each target site. PS values, ranging from 22.7 to 95.1 percent (100 percent = identical composition), indicate a wide range of recovery that is partially controlled by the edaphic properties of the geomorphic surfaces. Statistical analyses show a strong pattern that indicates a greater variability in the degree of recovery for sites on older surfaces than on younger surfaces and a weak pattern that indicates an inverse relation between the degree of recovery and geomorphic age. Comparisons of the different effects of target site construction on the edaphic characteristics of each target site provides an explanation for these patterns and suggests the soil properties critical to the recovery process. Statistically significant negative or positive response to disturbance for most species are independent of the age of the geomorphic surfaces; however, there is strong evidence for a shift in response for the common perennial species Acamptopappus sphaerocephalus, and to a lesser extent, Salazaria mexicana, Encelia farinosa, and Coldenia canescens, among different geomorphic surfaces.

  5. View of Lake Mead and Las Vegas, Nevada area from Sklyab

    NASA Image and Video Library

    1973-08-01

    SL3-28-059 (July-September 1973) --- A vertical view of the Lake Mead and Las Vegas, Nevada area as photographed from Earth orbit by one of the six lenses of the Itek-furnished S190-A Multispectral Photographic Facility Experiment aboard the Skylab space station. Lake Mead is water of the Colorado River impounded by Hoover Dam. Most of the land in the picture is Nevada. However, a part of the northwest corner of Arizona can be seen. Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior?s Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. Photo credit: NASA

  6. Selected hydrologic data for the Beaver Dam Wash area, Washington County, Utah, Lincoln County, Nevada, and Mohave County, Arizona, 1991-95

    USGS Publications Warehouse

    Enright, Michael

    1996-01-01

    The hydrologic data in this report were collected in Beaver Dam Wash and adjacent areas of Washington County, Utah, Lincoln County, Nevada, andMohave County, Arizona, from 1991 to 1995; some historical data from as far back as 1932 are included for comparative purposes. The data include records of about 100 wells, drillers' and geologic logs of selected wells, and results of chemical analyses of water from wells, springs, and surface-water sites. Discharge, water temperature, and specific-conductance measurements are reported for 33 surface-water and spring sites. Daily mean discharge data are reported for two U.S. Geological Survey streamflow-gaging stations on Beaver Dam Wash (1992-95). The data were collected as part of a study done by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Resources; the Nevada Department of Conservation and Natural Resources; and the Arizona Department of Water Resources.

  7. Selenium concentrations in the Colorado pikeminnow (Ptychocheilus lucius): Relationship with flows in the upper Colorado River

    USGS Publications Warehouse

    Osmundson, B.C.; May, T.W.; Osmundson, D.B.

    2000-01-01

    A Department of the Interior (DOI) irrigation drainwater study of the Uncompahgre Project area and the Grand Valley in western Colorado revealed high selenium concentrations in water, sediment, and biota samples. The lower Gunnison River and the Colorado River in the study area are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus). Because of the endangered status of these fish, sacrificing individuals for tissue residue analysis has been avoided; consequently, little information existed regarding selenium tissue residues. In 1994, muscle plugs were collected from a total of 39 Colorado pikeminnow captured at various Colorado River sites in the Grand Valley for selenium residue analysis. The muscle plugs collected from 16 Colorado pikeminnow captured at Walter Walker State Wildlife Area (WWSWA) contained a mean selenium concentration of 17 ??g/g dry weight, which was over twice the recommended toxic threshold guideline concentration of 8 ??g/g dry weight in muscle tissue for freshwater fish. Because of elevated selenium concentrations in muscle plugs in 1994, a total of 52 muscle plugs were taken during 1995 from Colorado pikeminnow staging at WWSWA. Eleven of these plugs were from fish previously sampled in 1994. Selenium concentrations in 9 of the 11 recaptured fish were significantly lower in 1995 than in 1994. Reduced selenium in fish may in part be attributed to higher instream flows in 1995 and lower water selenium concentrations in the Colorado River in the Grand Valley. In 1996, muscle plugs were taken from 35 Colorado squawfish captured at WWSWA, and no difference in mean selenium concentrations were detected from those sampled in 1995. Colorado River flows during 1996 were intermediate to those measured in 1994 and 1995.

  8. Selenium concentrations in the Colorado pikeminnow (Ptychocheilus lucius): relationship with flows in the upper Colorado River.

    PubMed

    Osmundson, B C; May, T W; Osmundson, D B

    2000-05-01

    A Department of the Interior (DOI) irrigation drainwater study of the Uncompahgre Project area and the Grand Valley in western Colorado revealed high selenium concentrations in water, sediment, and biota samples. The lower Gunnison River and the Colorado River in the study area are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus). Because of the endangered status of these fish, sacrificing individuals for tissue residue analysis has been avoided; consequently, little information existed regarding selenium tissue residues. In 1994, muscle plugs were collected from a total of 39 Colorado pikeminnow captured at various Colorado River sites in the Grand Valley for selenium residue analysis. The muscle plugs collected from 16 Colorado pikeminnow captured at Walter Walker State Wildlife Area (WWSWA) contained a mean selenium concentration of 17 microg/g dry weight, which was over twice the recommended toxic threshold guideline concentration of 8 microg/g dry weight in muscle tissue for freshwater fish. Because of elevated selenium concentrations in muscle plugs in 1994, a total of 52 muscle plugs were taken during 1995 from Colorado pikeminnow staging at WWSWA. Eleven of these plugs were from fish previously sampled in 1994. Selenium concentrations in 9 of the 11 recaptured fish were significantly lower in 1995 than in 1994. Reduced selenium in fish may in part be attributed to higher instream flows in 1995 and lower water selenium concentrations in the Colorado River in the Grand Valley. In 1996, muscle plugs were taken from 35 Colorado squawfish captured at WWSWA, and no difference in mean selenium concentrations were detected from those sampled in 1995. Colorado River flows during 1996 were intermediate to those measured in 1994 and 1995.

  9. 33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and Reservoir in the interest of flood control as follows: (a) Water Control Plan—(1) General..., flood control, stream regulation, generation of power, irrigation, water supply, and recreation uses. (2) Overall plan for water control. Within the Colorado River Basin, four Federal projects provide flood...

  10. 33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and Reservoir in the interest of flood control as follows: (a) Water Control Plan—(1) General..., flood control, stream regulation, generation of power, irrigation, water supply, and recreation uses. (2) Overall plan for water control. Within the Colorado River Basin, four Federal projects provide flood...

  11. Ready for College in Colorado: Evaluation of the Colorado SUN and the College Connection Program

    ERIC Educational Resources Information Center

    Bragg, Debra D.

    2010-01-01

    In fall 2007, the state of Colorado received one of four federal grants from the Ready for College (RFC) grant program of the Office of Vocational and Adult Education (OVAE), U.S. Department of Education. The Colorado (CO) SUN project (where SUN stands for Success UNlimited) was designed to identify and enhance innovative practices from Colorado's…

  12. Do predators influence the distribution of age-0 kokanee in a Colorado Reservoir?

    USGS Publications Warehouse

    Hardiman, J.M.; Johnson, B.M.; Martinez, P.J.

    2004-01-01

    Seasonal changes in reservoir conditions such as productivity, light, and temperature create spatiotemporal variation in habitat that may segregate or aggregate predators and prey, producing implications for the distribution, growth, and survival of fishes. We used hydroacoustics to document the diel vertical distribution of age-0 kokanee Oncorhynchus nerka relative to environmental gradients at Blue Mesa Reservoir, Colorado, during May-August of 2002. Temperature, light, and zooplankton density profiles were examined relative to foraging conditions for kokanee and their primary predator, lake trout Salvelinus namaycush. Age-0 kokanee displayed large diel vertical migrations in May despite the lack of an energetic advantage before reservoir stratification. Age-0 kokanee minimized near-surface foraging at this time, perhaps to avoid predation by visual predators, such as lake trout, in the well-lit surface waters. Strong reservoir stratification in midsummer appeared to provide a thermal refuge from lake trout that the kokanee exploited. By August vertical migrations were shallow and most kokanee remained in the epilimnion throughout the day. Although the energetic implications of the late-summer strategy are unclear, it appears that kokanee were responding to changes in their predator environment. A robust model for kokanee diel vertical migration across a range of systems should include a predator avoidance component.

  13. Fossil Scenedesmus (Chlorococcales) from the Raton Formation, Colorado and New Mexico, U.S.A.

    USGS Publications Warehouse

    Farley, Fleming R.

    1989-01-01

    Fossilized coenobia of the alga Scenedesmus (Chlorococcales) were recovered in palynomorph assemblages from a lower Paleocene mudstone in the Upper Cretaceous and Paleocene Raton Formation of Colorado and New Mexico. This is the first description of fossil Scenedesmus from Tertiary rocks. Two species, Scenedesmus tschudyi sp. nov. and Scenedesmus hanleyi sp. nov., are present in the assemblages. Coenobia of S. tschudyi sp. nov. are characterized by lunate terminal cells and fusiform median cells. As in species of modern Scenedesmus, coenobia of S. tschudyi sp. nov. occur with four or eight cells. Coenobia of S. hanleyi sp. nov. have four oval cells and are smaller than coenobia of S. tschudyi sp. nov. Fossil coenobia of Scenedesmus co-occur with the fossil alga Pediastrum in Raton Formation mudstones. Because these genera co-occur in modern lakes and ponds, the co-occurrence of fossil Scenedesmus and Pediastrum in ancient nonmarine rocks is interpreted to indicate deposition of sediment in freshwater lakes and ponds. ?? 1989.

  14. Use of Superposition Models to Simulate Possible Depletion of Colorado River Water by Ground-Water Withdrawal

    USGS Publications Warehouse

    Leake, Stanley A.; Greer, William; Watt, Dennis; Weghorst, Paul

    2008-01-01

    According to the 'Law of the River', wells that draw water from the Colorado River by underground pumping need an entitlement for the diversion of water from the Colorado River. Consumptive use can occur through direct diversions of surface water, as well as through withdrawal of water from the river by underground pumping. To develop methods for evaluating the need for entitlements for Colorado River water, an assessment of possible depletion of water in the Colorado River by pumping wells is needed. Possible methods include simple analytical models and complex numerical ground-water flow models. For this study, an intermediate approach was taken that uses numerical superposition models with complex horizontal geometry, simple vertical geometry, and constant aquifer properties. The six areas modeled include larger extents of the previously defined river aquifer from the Lake Mead area to the Yuma area. For the modeled areas, a low estimate of transmissivity and an average estimate of transmissivity were derived from statistical analyses of transmissivity data. Aquifer storage coefficient, or specific yield, was selected on the basis of results of a previous study in the Yuma area. The USGS program MODFLOW-2000 (Harbaugh and others, 2000) was used with uniform 0.25-mile grid spacing along rows and columns. Calculations of depletion of river water by wells were made for a time of 100 years since the onset of pumping. A computer program was set up to run the models repeatedly, each time with a well in a different location. Maps were constructed for at least two transmissivity values for each of the modeled areas. The modeling results, based on the selected transmissivities, indicate that low values of depletion in 100 years occur mainly in parts of side valleys that are more than a few tens of miles from the Colorado River.

  15. State summaries: Colorado

    USGS Publications Warehouse

    Keller, J.; Carroll, C.; Widmann, B.

    2006-01-01

    According to the Colorado Geological Survey (CGS), Colorado's mining industry enjoyed a record-breaking year in 2005. For the whole year, the total value of nonfuel minerals, coal and uranium produced in the state in 2005 amounted to $2.4 billion. The production value of $1.52 billion in the nonfuel sector broke the previous record of $1.3 billion set in 1980, and is 60% higher than the revised 2004 CGS estimate of $950.5 million. The United States Geological Survey (USGS) ranked Colorado ninth among the states in nonfuel mineral value, up from 17th in 2004. About $1 billion of the nonfuel total is from metal mining. New record-high productions were achieved not only for molybdenum but also for coal and goal.

  16. Tracer-dilution experiments and solute-transport simulations for a mountain stream, Saint Kevin Gulch, Colorado. Water resources investigation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Broshears, R.E.; Bencala, K.E.; Kimball, B.A.

    In 1986, the U.S. Geological Survey began an investigation to characterize within-stream hydrologic, chemical, and biological processes that influence the distribution and transport of hazardous constituents in the headwaters of the Arkansas River. The report describes the results of tracer-dilution experiments and associated solute-transport simulations for a 1804-meter stretch of Saint Kevin Gulch, a stream affected by acid mine drainage in Lake County, Colorado. The report describes transient changes in tracer (lithium chloride) concentration at six instream sites.

  17. Parasitism and body condition in humpback chub from the Colorado and Little Colorado Rivers, Grand Canyon, Arizona

    USGS Publications Warehouse

    Hoffnagle, Timothy L.; Choudhury, Anindo; Cole, Rebecca A.

    2006-01-01

    Glen Canyon Dam has greatly altered the Colorado River in Grand Canyon. The Little Colorado River (LCR) provides a small refuge of seasonally warm and turbid water that is thought to be more suitable than the Colorado River for endangered humpback chub Gila cypha. However, the LCR has low productivity and contains nonnative fishes and parasites, which pose a threat to humpback chub. The Colorado River hosts a different suite of nonnative fishes and is cold and clear but more productive. We compared condition factor (K), abdominal fat index (AFI), and presence and number of two introduced pathogenic parasites (Lernaea cyprinacea and Bothriocephalus acheilognathi) between juvenile (<150 mm total length) humpback chub from the LCR and those from the Colorado River during 1996a??1999. Both K and AFI were lower and L. cyprinacea prevalence and B. acheilognathi prevalence were higher in LCR fish than in Colorado River fish for all years. Mean K and AFI were 0.622 and 0.48, respectively, in the LCR and 0.735 and 2.02, respectively, in the Colorado River, indicating that fish in the Colorado River were more robust. Mean prevalence of L. cyprinacea was 23.9% and mean intensity was 1.73 L. cyprinacea/infected fish in the LCR, whereas prevalence was 3.2% and intensity was 1.0 L. cyprinacea/infected fish in the Colorado River. Mean prevalence of B. acheilognathi was 51.0% and mean intensity was 25.0 B. acheilognathi/infected fish in the LCR, whereas prevalence was 15.8% and intensity was 12.0 B. acheilognathi/infected fish in the Colorado River. Increased parasitism and poorer body condition in humpback chub from the LCR challenge the paradigm that warmer LCR waters are more suitable for humpback chub than the colder Colorado River and indicate the need to consider the importance and benefits of all available habitats, as well as biotic and abiotic factors, when managing endangered species and their environment.

  18. Characterization and modeling of illite crystal particles and growth mechanisms in a zoned hydrothermal deposit, Lake City, Colorado

    USGS Publications Warehouse

    Bove, D.J.; Eberl, D.D.; McCarty, D.K.; Meeker, G.P.

    2002-01-01

    Mean thickness measurements and crystal-thickness distributions (CTDs) of illite particles vary systematically with changes in hydrothermal alteration type, fracture density, and attendant mineralization in a large acid-sulfate/Mo-porphyry hydrothermal system at Red Mountain, near Lake City, Colorado. The hydrothermal illites characterize an extensive zone of quartz-sericite-pyrite alteration beneath two deeply rooted bodies of magmatic-related, quartz-alunite altered rock. Nineteen illites from a 3000 ft vertical drill hole were analyzed by XRD using the PVP-10 intercalation method and the computer program MudMaster (Bertaut-Warren-Averbach technique). Mean crystallite thicknesses, as determined from 001 reflections, range from 5-7 nanometers (nm) at depths from 0-1700 ft, then sharply increase to 10-16 nm at depths between 1800-2100 ft, and decrease again to 4-5 nm below this level. The interval of largest particle thickness correlates strongly with the zone of most intense quartz-sericite-pyrite alteration (QSP) and attendant high-density stockwork fracturing, and with the highest concentrations of Mo within the drill core. CTD shapes for the illite particles fall into two main categories: asymptotic and lognormal. The shapes of the CTDs are dependent on conditions of illite formation. The asymptotic CTDs correspond to a nucleation and growth mechanism, whereas surface-controlled growth was the dominant mechanism for the lognormal CTDs. Lognormal CTDs coincide with major through-going fractures or stockwork zones, whereas asymptotic CTDs are present in wallrock distal to these intense fracture zones. The increase in illite particle size and the associated zone of intense QSP alteration and stockwork veining was related by proximity to the dacitic magma(s), which supplied both reactants and heat to the hydrothermal system. However, no changes in illite polytype, which in other studies reflect temperature transitions, were observed within this interval.

  19. Hydrography and circulation of ice-marginal lakes at Bering Glacier, Alaska, U.S.A.

    USGS Publications Warehouse

    Josberger, E.G.; Shuchman, R.A.; Meadows, G.A.; Savage, S.; Payne, J.

    2006-01-01

    An extensive suite of physical oceanographic, remotely sensed, and water quality measurements, collected from 2001 through 2004 in two ice-marginal lakes at Bering Glacier, Alaska-Berg Lake and Vitus Lake-show that each has a unique circulation controlled by their specific physical forcing within the glacial system. Conductivity profiles from Berg Lake, perched 135 m a.s.l., show no salt in the lake, but the temperature profiles indicate an apparently unstable situation, the 4??C density maximum is located at 10 m depth, not at the bottom of the lake (90 m depth). Subglacial discharge from the Steller Glacier into the bottom of the lake must inject a suspended sediment load sufficient to marginally stabilize the water column throughout the lake. In Vitus Lake, terminus positions derived from satellite imagery show that the glacier terminus rapidly retreated from 1995 to the present resulting in a substantial expansion of the volume of Vitus Lake. Conductivity and temperature profiles from the tidally influenced Vitus Lake show a complex four-layer system with diluted (???50%) seawater in the bottom of the lake. This lake has a complex vertical structure that is the result of convection generated by ice melting in salt water, stratification within the lake, and freshwater entering the lake from beneath the glacier and surface runoff. Four consecutive years, from 2001 to 2004, of these observations in Vitus Lake show little change in the deep temperature and salinity conditions, indicating limited deep water renewal. The combination of the lake level measurements with discharge measurements, through a tidal cycle, by an acoustic Doppler Current Profiler (ADCP) deployed in the Seal River, which drains the entire Bering system, showed a strong tidal influence but no seawater entry into Vitus Lake. The ADCP measurements combined with lake level measurements established a relationship between lake level and discharge, which when integrated over a tidal cycle, gives a

  20. Response of lake chemistry to atmospheric deposition and climate in selected Class I wilderness areas in the western United States, 1993-2009

    USGS Publications Warehouse

    Mast, M. Alisa

    2011-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Forest Service, Air Resource Management, conducted a study to evaluate long-term trends in lake-water chemistry for 64 high-elevation lakes in selected Class I wilderness areas in Colorado, Idaho, Utah, and Wyoming during 1993 to 2009. Understanding how and why lake chemistry is changing in mountain areas is essential for effectively managing and protecting high-elevation aquatic ecosystems. Trends in emissions, atmospheric deposition, and climate variables (air temperature and precipitation amount) were evaluated over a similar period of record. A main objective of the study was to determine if changes in atmospheric deposition of contaminants in the Rocky Mountain region have resulted in measurable changes in the chemistry of high-elevation lakes. A second objective was to investigate linkages between lake chemistry and air temperature and precipitation to improve understanding of the sensitivity of mountain lakes to climate variability.

  1. Environmental Assessment for the Bear Creek Dam and Lake Project Master Plan, South Platte River, Colorado

    DTIC Science & Technology

    2012-09-01

    erosion. Piney Creek alluvium along the low terraces is Holocene in age and rock fragments in this area have igneous or metamorphic lithology with...to the Red Rocks Amphitheatre and Bandimere Speedway, which are a brief drive from the Park. Recreational use of Bear Creek Lake is also... US Army Corps of Engineers ® Omaha District Environmental Assessment for the Bear Creek Dam and Lake Project Master Plan South Platte River

  2. NASA Helps Build Colorado Economy

    NASA Image and Video Library

    2010-12-13

    Colorado State Governor Bill Ritter delivers remarks at the Colorado State Capitol in Denver on Monday, Dec. 13, 2010, prior to the signing of an agreement with NASA that creates a Technology Acceleration Program and Regional Innovation Cluster for Aerospace and Clean Energy. A manufacturing park focused on rapid new product development and production will be developed to assist growing Colorado businesses while promoting the commercialization of technology developed for the space program. Photo Credit: (NASA/Bill Ingalls)

  3. Geologic Assessment of Coal in the Colorado Plateau: Arizona, Colorado, New Mexico, and Utah

    USGS Publications Warehouse

    Kirschbaum, Mark A.; Roberts, Lauara N.R.; Biewick, Laura

    2000-01-01

    This CD-ROM set contains a geologic assessment of coal deposits of the Colorado Plateau region and new resource estimates for selected assessment units within the Colorado Plateau. Original resource estimates (in-place resources before production) for the 12 priority assessment units of the Colorado Plateau exceed one half trillion short tons of coal in beds greater than 1 ft thick and under less than 6,000 ft of overburden. The coal is high quality and low sulfur, and a portion of these resources will provide future energy production for the Nation. Disc 1, in Portable Document Format, contains results of the assessment in summary and (or) technical reports for 12 priority coal assessment units in the Colorado Plateau and also contains an ArcView Data Publisher project, which is an interactive geographic information system of digital data collected during the assessment. Disc 2 contains stratigraphic data bases for seven of the priority coal assessment areas within the Colorado Plateau region and an ArcView project identical to the ArcView Data Publisher project on disc 1 except that it retains some of the functionality that is disabled in the ArcView Data Publisher program.

  4. 78 FR 77397 - Flood Control Regulations, Marshall Ford Dam (Mansfield Dam and Lake Travis), Colorado River, Texas

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-23

    ..., and Section 103 of the Marine Protection, Research and Sanctuaries Act of 1972, the current OMB... Dam & Res...... TX Travis Colorado R...... F 779.8 714.0 681.0 29060 18955 PL 73-392....... LCRA. NEIM... by contacting the LCRA offices in Austin, Texas, or the offices of the U.S. Army Corps of Engineers...

  5. 75 FR 52935 - Colorado Interstate Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-30

    ... Interstate Gas Company (CIG), P.O. Box 1087, Colorado Springs, Colorado 80944, pursuant to section 7(c) of.... Susan C. Stires, Director, Regulatory Affairs, Colorado Interstate Gas Company, P.O. Box 1087, Colorado... President and General Counsel, Colorado Interstate Gas Company; P.O. Box 1087, Colorado Springs, Colorado...

  6. NASA Helps Build Colorado Economy

    NASA Image and Video Library

    2010-12-13

    Colorado Association for Manufacturing and Technology (CAMT) CEO Elaine Thorndike delivers remarks at the Colorado State Capitol in Denver on Monday, Dec. 13, 2010, prior to the signing of an agreement with NASA that creates a Technology Acceleration Program and Regional Innovation Cluster for Aerospace and Clean Energy. A manufacturing park focused on rapid new product development and production will be developed to assist growing Colorado businesses while promoting the commercialization of technology developed for the space program. Photo Credit: (NASA/Bill Ingalls)

  7. Colorado Children's Budget 2005

    ERIC Educational Resources Information Center

    Colorado Children's Campaign, 2005

    2005-01-01

    The Children's Budget is a comprehensive report on funding for children's services in Colorado. This report provides a six- year funding history for more than 50 programs funded with state, local, and federal dollars. The Colorado Children's Budget analyzes reductions in programs and services during the economic downturn. The data in the…

  8. Evaluating lake stratification and temporal trends by using near-continuous water-quality data from automated profiling systems for water years 2005-09, Lake Mead, Arizona and Nevada

    USGS Publications Warehouse

    Veley, Ronald J.; Moran, Michael J.

    2012-01-01

    and well-defined maxima and minima in specific-conductance and dissolved-oxygen profiles were observed at deep-water stations during the summer months. Specific-conductance maxima were likely the result of inflow of water from either the Las Vegas Wash or Muddy/Virgin Rivers or both, while the minima were likely the result of inflow of water from the Colorado River. Maxima and minima for dissolved oxygen were likely the result of primary productivity blooms and their subsequent decay. Temporal-trend analyses indicated that specific conductance decreased at all stations over the period of record, except for Las Vegas Bay (Site 3), where specific conductance increased. Temperature also decreased over the period of record at deep-water stations for certain lake layers. Decreasing temperature and specific conductance at deep-water stations is the result of decreasing values in these parameters in water coming from the Colorado River. Quagga mussels (Dreissena rostriformis bugensis), however, could play a role in trends of decreasing specific conductance through incorporation of calcite in their shells. Trends of decreasing turbidity and pH at deep-water stations support the hypothesis that quagga mussels could be having an effect on the physical properties and water chemistry of Lake Mead. Unlike other stations, Las Vegas Bay (Site 3) had increasing specific conductance and is interpreted as the result of lowering lake levels decreasing the volume of lake water available for mixing and dilution of the high-conductance water coming from Las Vegas Wash. Dissolved oxygen increased over the period of record in some lake layers at the deep-water stations. Increasing dissolved oxygen at deep-water stations is believed to result, in part, from a reduction of phosphorus entering Lake Mead and the concomitant reduction of biological oxygen demand.

  9. 7 CFR 948.151 - Colorado Potato Committee membership.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Colorado Potato Committee membership. 948.151 Section... POTATOES GROWN IN COLORADO Rules and Regulations Modification of Inspection Requirements § 948.151 Colorado Potato Committee membership. The Colorado Potato Committee shall be comprised of six members and...

  10. 7 CFR 948.151 - Colorado Potato Committee membership.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Colorado Potato Committee membership. 948.151 Section... POTATOES GROWN IN COLORADO Rules and Regulations Modification of Inspection Requirements § 948.151 Colorado Potato Committee membership. The Colorado Potato Committee shall be comprised of six members and...

  11. 7 CFR 948.151 - Colorado Potato Committee membership.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Colorado Potato Committee membership. 948.151 Section... POTATOES GROWN IN COLORADO Rules and Regulations Modification of Inspection Requirements § 948.151 Colorado Potato Committee membership. The Colorado Potato Committee shall be comprised of six members and...

  12. 7 CFR 948.151 - Colorado Potato Committee membership.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Colorado Potato Committee membership. 948.151 Section... POTATOES GROWN IN COLORADO Rules and Regulations Modification of Inspection Requirements § 948.151 Colorado Potato Committee membership. The Colorado Potato Committee shall be comprised of six members and...

  13. 7 CFR 948.151 - Colorado Potato Committee membership.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Colorado Potato Committee membership. 948.151 Section... POTATOES GROWN IN COLORADO Rules and Regulations Modification of Inspection Requirements § 948.151 Colorado Potato Committee membership. The Colorado Potato Committee shall be comprised of six members and...

  14. Climate Change in Colorado: Findings and Scientific Challenges

    NASA Astrophysics Data System (ADS)

    Barsugli, J.; Ray, A.; Averyt, K.; Wolter, K.; Hoerling, M. P.

    2008-12-01

    In response to the risks associated with anthropogenic climate change, Governor Ritter issued the Colorado Climate Action Plan (CCAP) in 2007. In support of the adaptation component of the CCAP, the Colorado Water Conservation Board commissioned the Western Water Assessment at the University of Colorado to prepare the report "Climate Change in Colorado: A Synthesis to Support Water Resources Management and Adaptation." The objective of "Climate Change in Colorado" is to communicate the state of the science regarding the physical aspects of climate change that are important for evaluating impacts on Colorado's water resources. Accordingly, the document focuses on observed trends, modeling, attribution, and projections of hydroclimatic variables that are important for Colorado's water supply. Although many published datasets include information about Colorado, there are few climate studies that focus on the state. Consequently, many important analyses for Colorado are lacking. The report summarizes Colorado-specific findings from peer-reviewed regional studies, and presents new analyses derived from existing datasets. Here we will summarize the findings of the report, discuss the extent to which conclusions from West-wide studies hold in Colorado, and highlight the many scientific challenges that were faced in the preparation of the report. These challenges include interpreting observed and projected precipitation and temperature variability and trends, dealing with attribution and uncertainty at the state level, and justifying the relevance of climate model projections in a topographically complex state. A second presentation (Ray et al.) discusses the process of developing the report.

  15. Colorado Children's Budget 2012

    ERIC Educational Resources Information Center

    Buck, Beverly; Cuciti, Peggy L.; Baker, Robin

    2012-01-01

    The "Colorado Children's Budget 2012" examines the state's commitment to investing in the well-being of children. It tallies up Colorado's actual and planned investment during the past five years (Fiscal Year (FY) 2008-2009 through FY 2012-2013) on programs and services in four areas: Early Childhood Learning and Development, K-12…

  16. Colorado Children's Budget 2011

    ERIC Educational Resources Information Center

    Colorado Children's Campaign, 2011

    2011-01-01

    "Colorado Children's Budget 2011" tallies up Colorado's public investments during FY 2007-08 through FY 2011-12 for programs and services that enhance the well-being of children across four domains--Early Childhood, K-12 Education, Health, and Other Supports. It is intended to be a resource guide for policymakers and advocates who are…

  17. NASA Helps Build Colorado Economy

    NASA Image and Video Library

    2010-12-13

    NIST MEP Director Roger Kilmer delivers remarks at the Colorado State Capitol in Denver on Monday, Dec. 13, 2010, prior to the signing of an agreement between the Colorado Association for Manufacturing and Technology (CAMT) and NASA that creates a Technology Acceleration Program and Regional Innovation Cluster for Aerospace and Clean Energy. A manufacturing park focused on rapid new product development and production will be developed to assist growing Colorado businesses while promoting the commercialization of technology developed for the space program. Photo Credit: (NASA/Bill Ingalls)

  18. Colorado River fish monitoring in Grand Canyon, Arizona; 2000 to 2009 summary

    USGS Publications Warehouse

    Makinster, Andrew S.; Persons, William R.; Avery, Luke A.; Bunch, Aaron J.

    2010-01-01

    Long-term fish monitoring in the Colorado River below Glen Canyon Dam is an essential component of the Glen Canyon Dam Adaptive Management Program (GCDAMP). The GCDAMP is a federally authorized initiative to ensure that the primary mandate of the Grand Canyon Protection Act of 1992 to protect resources downstream from Glen Canyon Dam is met. The U.S. Geological Survey's Grand Canyon Monitoring and Research Center is responsible for the program's long-term fish monitoring, which is implemented in cooperation with the Arizona Game and Fish Department, U.S. Fish and Wildlife Service, SWCA Environmental Consultants, and others. Electrofishing and tagging protocols have been developed and implemented for standardized annual monitoring of Colorado River fishes since 2000. In 2009, sampling occurred throughout the river between Lees Ferry and Lake Mead for 38 nights over two trips. During the two trips, scientists captured 6,826 fish representing 11 species. Based on catch-per-unit-effort, salmonids (for example, rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta)) increased eightfold between 2006 and 2009. Flannelmouth sucker (Catostomus latipinnis) catch rates were twice as high in 2009 as in 2006. Humpback chub (Gila cypha) catches were low throughout the 10-year sampling period.

  19. Colorado statewide historic bridge inventory.

    DOT National Transportation Integrated Search

    2011-05-01

    The purpose of the Colorado statewide historic bridge inventory was to document and evaluate the National : Register of Historic Places eligibility all on-system highway bridges and grade separation structures built in : Colorado between 1959 and 196...

  20. Colorado Library Program Assessment

    ERIC Educational Resources Information Center

    Russell, Becky

    2012-01-01

    Colorado school librarians are in the midst of a crisis. According to a 2009-2010 survey of public schools in Colorado, just 23% of elementary schools have an endorsed librarian, while 37% of middle schools and 32% of high schools report having an endorsed librarian. This report also shows how these percentages have dropped in just a two-year…

  1. Colorado State Capitol Geothermal project

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shepherd, Lance

    Colorado State Capitol Geothermal Project - Final report is redacted due to space constraints. This project was an innovative large-scale ground-source heat pump (GSHP) project at the Colorado State Capitol in Denver, Colorado. The project employed two large wells on the property. One for pulling water from the aquifer, and another for returning the water to the aquifer, after performing the heat exchange. The two wells can work in either direction. Heat extracted/added to the water via a heat exchanger is used to perform space conditioning in the building.

  2. Fate and Transport of Mercury in the Four Corners Region of Southern Colorado

    NASA Astrophysics Data System (ADS)

    Peltz, C. D.; Nydick, K.; Wright, W.

    2011-12-01

    Mercury (Hg) is a growing threat to human health in the Four Corners region of southwestern Colorado. Five reservoirs along the southern flank of the San Juan Mountains currently have fish advisories due to Hg, and data from Mercury Deposition Network (MDN) sites and lake sediment cores indicate that in the Four Corners region, Hg deposition and concentration in precipitation are at some of the highest rates in the U.S. Compounding the high deposition rates of Hg, are the increases in forest fires in the region which may significantly contribute to the transport of Hg from terrestrial sites to bodies of water. Based on preliminary analysis of lake sediment cores and deposition data from the MDN, we sought to understand, (1) the sources of Hg; (2) the flux rates of Hg in alpine lake sediments; and (3), Hg accumulation in aquatic biota. Our study involved three phases, and included examining lake sediments and wet deposition of Hg at high elevation sites in the Weminuche Wilderness, applying back trajectory modeling of storm events that deposited Hg at Mesa Verde National Park and Molas Pass (San Juan County, CO), and ultimately analyzing how wildfire may contribute to the transport, deposition, and subsequent bioavailability in aquatic food webs. Our results suggest that flux rates of Hg in alpine lakes in the Weminuche Wilderness are 1.6 to 3 times greater than pre-industrial rates, with concentrations of total Hg in zooplankton ranging from 36 to 806 ng/g dry mass, and CH3Hg+ concentrations ranging from 7 to 185 ng/g dry mass. Back trajectory modeling was conducted on sixty-nine precipitation events that deposited Hg at Molas Pass and Mesa Verde National Park with the results indicating that precipitation events at these sites, which tracked north from 130 - 220 degrees azimuth, had concentrations of Hg above the background concentration of 11 ng/L. Ongoing analysis of lake sediments and terrestrial soils in burned and unburned forest areas is examining the

  3. Surficial geology and distribution of post-impoundment sediment of the western part of Lake Mead based on a sidescan sonar and high-resolution seismic-reflection survey

    USGS Publications Warehouse

    Twichell, David C.; Cross, VeeAnn A.; Rudin, Mark J.; Parolski, Kenneth F.

    1999-01-01

    Sidescan sonar imagery and high-resolution seismic-reflection profiles were collected in Las Vegas Bay and Boulder Basin of Lake Mead to determine the surficial geology as well as the distribution and thickness of sediment that has accumulated in these areas of the lake since the completion of Hoover Dam in 1935 (Gould, 1951). Results indicate that the accumulation of post-impoundment sediment is restricted to the original Colorado River bed which runs down the axis of Boulder Basin from Boulder Canyon to Hoover Dam, and the old Las Vegas Creek bed that bisects Las Vegas Bay. The sediment cover along the original Colorado River bed is continuous and is typically greater than 10-m thick throughout much of its length with the thickness in some areas exceeding 35 meters. The flat-lying nature of the deposits suggests that they are the result of turbidity currents that flow the length of the lake. The sediment cover in Las Vegas Bay is much thinner (rarely exceeding 2 m in thickness) and more discontinuous. The source for these sediments presumably is Las Vegas Wash and a series of other ephemeral washes that empty into this part of the lake. The presence of sediments along the entire length of the Las Vegas Creek bed suggests that turbidity currents probably are active here as well, and that sediment has been transported from these streams at least 10 km down the axis of this valley to where it enters Boulder Basin. Alluvial deposits and rock outcrops are still exposed on large parts of the lake floor.

  4. 75 FR 30806 - Colorado Interstate Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... Interstate Gas Company (CIG), P.O. Box 1087, Colorado Springs, Colorado 80944, filed with the Federal Energy... Susan C. Stires, Director, Regulatory Affairs, Colorado Interstate Gas Company, P.O. Box 1087, Colorado..., P.O. Box 1087, Colorado Springs, Colorado 80944 at 719-520-4898. Pursuant to section 157.9 of the...

  5. Colorado Early Childhood Study.

    ERIC Educational Resources Information Center

    Colorado State Dept. of Education, Denver. Planning and Evaluation Unit.

    The Colorado State Board of Education allocated Title IV-V funds in 1975 for a study of the status of early childhood education in Colorado. The purposes of the study were to: (1) gather data relevant to early childhood education on the status of all children from birth through age 5; (2) identify needs of children of this age within the state;…

  6. 7 CFR 948.51 - Colorado Potato Committee.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Colorado Potato Committee. 948.51 Section 948.51... Order Regulating Handling Committees § 948.51 Colorado Potato Committee. The Colorado Potato Committee... selected from each area committee. Committeemen shall be selected by the Secretary from nominations of area...

  7. 7 CFR 948.51 - Colorado Potato Committee.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Colorado Potato Committee. 948.51 Section 948.51... Order Regulating Handling Committees § 948.51 Colorado Potato Committee. The Colorado Potato Committee... selected from each area committee. Committeemen shall be selected by the Secretary from nominations of area...

  8. 7 CFR 948.51 - Colorado Potato Committee.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Colorado Potato Committee. 948.51 Section 948.51... Order Regulating Handling Committees § 948.51 Colorado Potato Committee. The Colorado Potato Committee... selected from each area committee. Committeemen shall be selected by the Secretary from nominations of area...

  9. 7 CFR 948.51 - Colorado Potato Committee.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Colorado Potato Committee. 948.51 Section 948.51... Order Regulating Handling Committees § 948.51 Colorado Potato Committee. The Colorado Potato Committee... selected from each area committee. Committeemen shall be selected by the Secretary from nominations of area...

  10. 7 CFR 948.51 - Colorado Potato Committee.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Colorado Potato Committee. 948.51 Section 948.51... Order Regulating Handling Committees § 948.51 Colorado Potato Committee. The Colorado Potato Committee... selected from each area committee. Committeemen shall be selected by the Secretary from nominations of area...

  11. Toxicity of inorganic contaminants, individually and in environmental mixtures, to three endangered fishes (Colorado squawfish, bonytail, and razorback sucker)

    USGS Publications Warehouse

    Buhl, Kevin J.; Hamilton, S.J.

    1996-01-01

    Two life stages of three federally-listed endangered fishes, Colorado squawfish (Ptychocheilus lucius), bonytail (Gila elegans), and razorback sucker (Xyrauchen texanus) were exposed to copper, selenate, selenite, and zinc individually, and to mixtures of nine inorganics in a reconstituted water that simulated the water quality of the middle Green River, Utah. The mixtures simulated environmental ratios of arsenate, boron, copper, molybdenum, selenate, selenite, uranium, vanadium, and zinc in two tributaries, Ashley Creek and Stewart Lake outlet, of the middle Green River. The rank order of toxicity of the individual inorganics, from most to least toxic, was: copper > zinc > selenite > selenate. Colorado squawfish larvae were more sensitive to all four inorganics and the two mixtures than the juveniles, whereas there was no consistent response between the two life stages for the other two species. There was no consistent difference in sensitivity to the inorganics among the three endangered fishes. Both mixtures exhibited either additive or greater than additive toxicity to these fishes. The primary toxic components in the mixtures, based on toxic units, were copper and zinc. Acute toxicity values were compared to measured environmental concentrations in the two tributaries to derive margins of uncertainty. Margins of uncertainty were low for both mixtures (9–22 for the Stewart Lake outlet mixture, and 12–32 for the Ashley Creek mixture), indicating that mixtures of inorganics derived from irrigation activities may pose a hazard to endangered fishes in the Green River.

  12. National Uranium Resource Evaluation: Durango Quadrangle, Colorado

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Theis, N.J.; Madson, M.E.; Rosenlund, G.C.

    1981-06-01

    The Durango Quadrangle (2/sup 0/), Colorado, was evaluated using National Uranium Resource Evaluation criteria to determine environments favorable for uranium deposits. General reconnaissance, geologic and radiometric investigations, was augmented by detailed surface examination and radiometric and geochemical studies in selected areas. Eight areas favorable for uranium deposits were delineated. Favorable geologic environments include roscoelite-type vanadium-uranium deposits in the Placerville and Barlow Creek-Hermosa Creek districts, sandstone uranium deposits along Hermosa Creek, and vein uranium deposits in the Precambrian rocks of the Needle Mountains area and in the Paleozoic rocks of the Tuckerville and Piedra River Canyon areas. The major portions ofmore » the San Juan volcanic field, the San Juan Basin, and the San Luis Basin within the quadrangle were judged unfavorable. Due to lack of information, the roscoelite belt below 1000 ft (300 m), the Eolus Granite below 0.5 mi (0.8 km), and the Lake City caldera are unevaluated. The Precambrian Y melasyenite of Ute Creek and the Animas Formation within the Southern Ute Indian Reservation are unevaluated due to lack of access.« less

  13. Native Fish Sanctuary Project - Sanctuary Development Phase, 2007 Annual Report

    USGS Publications Warehouse

    Mueller, Gordon A.

    2007-01-01

    Notable progress was made in 2007 toward the development of native fish facilities in the Lower Colorado River Basin. More than a dozen facilities are, or soon will be, online to benefit native fish. When this study began in 2005 no self-supporting communities of either bonytail or razorback sucker existed. Razorback suckers were removed from Rock Tank in 1997 and the communities at High Levee Pond had been compromised by largemouth bass in 2004. This project reversed that trend with the establishment of the Davis Cove native fish community in 2005. Bonytail and razorback sucker successfully produced young in Davis Cove in 2006. Bonytail successfully produced young in Parker Dam Pond in 2007, representing the first successful sanctuary established solely for bonytail. This past year, Three Fingers Lake received 135 large razorback suckers, and Federal and State agencies have agreed to develop a cooperative management approach dedicating a portion of that lake toward grow-out and (or) the establishment of another sanctuary. Two ponds at River's Edge Golf Course in Needles, California, were renovated in June and soon will be stocked with bonytail. Similar activities are taking place at Mohave Community College, Cerbat Cliffs Golf Course, Cibola High Levee Pond, Office Cove, Emerald Canyon Golf Course, and Bulkhead Cove. Recruitment can be expected as fish become sexually mature at these facilities. Flood-plain facilities have the potential to support 6,000 adult razorback suckers and nearly 20,000 bonytail if native fish management is aggressively pursued. This sanctuary project has assisted agencies in developing 15 native fish communities by identifying specific resource objectives for those sites, listing and prioritizing research opportunities and needs, and strategizing on management approaches through the use of resource-management plans. Such documents have been developed for Davis Cove, Cibola High Levee Pond, Parker Dam Pond, and Three Fingers Lake. We

  14. 78 FR 19304 - Notice of Intent To Repatriate Cultural Items: The Colorado College, Colorado Springs, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ..., Armstrong Hall, Room 201, 14 E. Cache La Poudre, Colorado Springs, CO 80903, telephone (719) 389-6201..., Room 201, 14 E. Cache La Poudre, Colorado Springs, CO 80903, telephone (719) 389-6201, before April 29...

  15. Reservoir-induced deformation and continental rheology in vicinity of Lake Mead, Nevada

    NASA Astrophysics Data System (ADS)

    Kaufmann, Georg; Amelung, Falk

    2000-07-01

    Lake Mead is a large reservoir in Nevada, formed by the construction of the 221-m-high Hoover Dam in the Black Canyon of the Colorado River. The lake encompasses an area of 635 km2, and the total volume of the reservoir is 35.5 km3. Filling started in February 1935. On the basis of a first-order leveling in 1935, several levelings were carried out to measure the deformation induced by the load of the reservoir. Subsidence in the central parts of the lake relative to the first leveling was around 120 mm (1941), 218 mm (1950), and 200 mm (1963). The subsidence pattern clearly shows relaxation of the underlying basement due to the water load of the lake, which ceased after 1950. Modeling of the relaxation process by means of layered, viscoelastic, compressible flat Earth models with a detailed representation of the spatial and temporal distribution of the water load shows that the thickness of the elastic crust underneath Lake Mead is 30±3 km. The data are also consistent with a 10-km-thick elastic upper crust and a 20-km-thick viscoelastic lower crust, with 1020 Pa s as a lower bound for its viscosity. The subcrust has an average viscosity of 1018±0.2 Pa s, a surprisingly low value. The leveling data constrain the viscosity profile down to ˜200 km depth.

  16. Persistence of Ethnicity: The Japanese of Colorado.

    ERIC Educational Resources Information Center

    Endo, Russell

    This paper presents an overview of the history of Japanese in Colorado. Japanese immigrants first came to Colorado between 1900 and 1910 as railroad laborers. Some became coal miners in southern Colorado; most others became farm laborers. Although the Japanese population during this period was small, communities developed in several locales. The…

  17. Colorado Academic Library Master Plan, Spring 1982.

    ERIC Educational Resources Information Center

    Breivik, Patricia Senn; And Others

    Based on a need to assess current library strengths and weaknesses and to project potential library roles in supporting higher education, this master plan makes a series of recommendations to Colorado's academic libraries. It is noted that the plan was endorsed by both the Colorado Commission on Higher Education and the Colorado State Department…

  18. USGS Colorado Water Science Center bookmark

    USGS Publications Warehouse

    ,

    2016-12-05

    The U.S. Geological Survey Colorado Water Science Center conducts its water-resources activities primarily in Colorado in cooperation with more than 125 different entities. These activities include extensive data-collection efforts and studies of streamflow, water quality, and groundwater to address many specific issues of concern to Colorado water-management entities and citizens. The collected data are provided in the National Water Information System, and study results are documented in reports and information served on the Internet.

  19. Assessment of total nitrogen and total phosphorus in selected surface water of the National Park Service Northern Colorado Plateau Network, Colorado, Utah, and Wyoming, from 1972 through 2007

    USGS Publications Warehouse

    Brown, Juliane B.; Thoma, David P.

    2012-01-01

    Nutrients are a nationally recognized concern for water quality of streams, rivers, groundwater, and water bodies. Nutrient impairment is documented by the U.S. Environmental Protection Agency as a primary cause of degradation in lakes and reservoirs, and nutrients are related to organic enrichment and oxygen depletion, which is an important cause of degradation in streams. Recently (2011), an effort to develop State-based numeric nutrient criteria has resulted in renewed emphasis on nutrients in surface water throughout the Nation. In response to this renewed emphasis and to investigate nutrient water quality for Northern Colorado Plateau Network streams, the U.S. Geological Survey, in cooperation with the National Park Service, assessed total nitrogen and total phosphorus concentration data for 93 sites in or near 14 National Park units for the time period 1972 through 2007.

  20. 40 CFR 81.306 - Colorado.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Colorado. 81.306 Section 81.306... AREAS FOR AIR QUALITY PLANNING PURPOSES Section 107 Attainment Status Designations § 81.306 Colorado. Colorado—1971 Sulfur Dioxide NAAQS (Primary and Secondary) Designated Area Does not meet primary standards...

  1. Comparison of abundances of chemical elements in mineralized and unmineralized sandstone of the Brushy Basin Member of the Morrison Formation, Smith Lake District, Grants uranium region, New Mexico

    USGS Publications Warehouse

    Pierson, C.T.; Spirakis, C.S.; Robertson, J.F.

    1983-01-01

    Statistical treatment of analytical data from the Mariano Lake and Ruby uranium deposits in the Smith Lake district, New Mexico, indicates that organic carbon, arsenic, barium, calcium, cobalt, copper, gallium, iron, lead, manganese, molybdenum, nickel, selenium, strontium, sulfur, vanadium, yttrium, and zirconium are concentrated along with uranium in primary ore. Comparison of the Smith Lake data with information from other primary deposits in the Grants uranium region and elsewhere in the Morrison Formation of the Colorado Plateau suggests that these elements, with the possible exceptions of zirconium and gallium and with the probable addition of aluminum and magnesium, are typically associated with primary, tabular uranium deposits. Chemical differences between the Ruby and Mariano Lake deposits are consistent with the interpretation that the Ruby deposit has been more affected by post-mineralization oxidizing solutions than has the Mariano Lake deposit.

  2. Colorado mileage-based user fee study.

    DOT National Transportation Integrated Search

    2013-12-01

    The Transportation Research Board, Government Accountability Office, and Colorado Transportation : Finance and Implementation Panel (CTFIP) suggested that Colorado pursue fees based on actual travel : as an alternative to the fuel tax. Revenues from ...

  3. Colorado Centennial-Bicentennial Teacher's Guide.

    ERIC Educational Resources Information Center

    Colorado Centennial - Bicentennial Commission, Denver.

    Intended for use by teachers in the establishment of curriculum to study centennial-bicentennial topics, the main purpose of this guide is to instill in students an appreciation of Colorado's system of government, resources, people, territory, and technology. Suggestions for teaching about seven major areas which relate to Colorado's heritage are…

  4. 40 CFR 81.306 - Colorado.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Colorado. 81.306 Section 81.306... AREAS FOR AIR QUALITY PLANNING PURPOSES Section 107 Attainment Status Designations § 81.306 Colorado. Colorado—SO2 Designated Area Does not meet primary standards Does not meet secondary standards Cannot be...

  5. 40 CFR 81.306 - Colorado.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Colorado. 81.306 Section 81.306... AREAS FOR AIR QUALITY PLANNING PURPOSES Section 107 Attainment Status Designations § 81.306 Colorado. Colorado—SO2 Designated Area Does not meet primary standards Does not meet secondary standards Cannot be...

  6. 40 CFR 81.306 - Colorado.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Colorado. 81.306 Section 81.306... AREAS FOR AIR QUALITY PLANNING PURPOSES Section 107 Attainment Status Designations § 81.306 Colorado. Colorado—SO2 Designated Area Does not meet primary standards Does not meet secondary standards Cannot be...

  7. Selected Colorado Technology Education Programs.

    ERIC Educational Resources Information Center

    Gloeckner, Gene W.

    The transition from industrial arts to technology education is a priority in Colorado. Millions of dollars have been and will be spent to renovate industrial arts facilities and laboratories. Four Colorado middle schools have exemplary technology education programs. The Eagle Crest Technology Education Laboratory is used for both middle and high…

  8. Colorado's Alternative School Calendar Program.

    ERIC Educational Resources Information Center

    Stiverson, C. L.

    1982-01-01

    Colorado's 22 school districts on a four-day week schedule, as authorized by Colorado Senate Bill 78, show comparable student achievement levels as those on a five-day schedule; support from parents, teachers; and students; improved energy savings and/or time savings; and cost savings. Five other possible benefits are listed. (LC)

  9. Colorado School Finance Partnership: Report and Recommendations. Financing Colorado's Future: Assessing Our School Finance System

    ERIC Educational Resources Information Center

    Colorado Children's Campaign, 2012

    2012-01-01

    Over the last decade, Colorado has emerged as a national leader in crafting innovative solutions for challenges facing its public school system. From implementing the Colorado Student Assessment Program (CSAP) and No Child Left Behind (NCLB) reforms to more recent legislation including standards and assessments for a preschool-through-college…

  10. An Investigation of the Impacts of Climate and Environmental Change on Alpine Lakes in the Uinta Mountains, Utah

    NASA Astrophysics Data System (ADS)

    Moser, K. A.; Hundey, E. J.; Porinchu, D. F.

    2007-12-01

    Aquatic systems in alpine and sub-alpine areas of the western United States are potentially impacted by atmospheric pollution and climate change. Because these mountainous regions are an important water resource for the western United States, it is critical to monitor and protect these systems. The Uinta Mountains are an east- west trending mountain range located on the border between Utah, Wyoming and Colorado and downwind of the Wasatch Front, Utah, which is characterized by a rapidly expanding population, as well as mining and industry. This alpine area provides water to many areas in Utah, and contributes approximately nine percent of the water supply to the Upper Colorado River. Our research is focused on determining the impacts of climate change and pollution on alpine lakes in the Uinta Mountains. The results presented here are based on limnological measurements made at 64 Uinta Mountain lakes spanning a longitude gradient of one degree and an elevation gradient of 3000 feet. At each lake maximum depth, conductivity, salinity, pH, Secchi depth, temperature, alkalinity, and concentrations of major anions, cations and trace metals were measured. Principal Components Analysis (PCA) was performed to determine relationships between these variables and to examine the variability of the values of these variables. Our results indicate that steep climate gradients related to elevation and longitude result in clear differences in limnological properties of the study sites, with high elevation lakes characterized by greater amounts of nitrate and nitrite compared to low elevation sites. As well, diatoms in these lakes indicate that many high elevation sites are mesotrophic to eutrophic, which is unexpected for such remote aquatic ecosystems. We hypothesize that elevated nitrate and nitrite levels at high elevation sites are related to atmospherically derived nitrogen, but are being exacerbated relative to lower elevation sites by greater snow cover and reduced plant

  11. Geologic Map of the Mount Trumbull 30' X 60' Quadrangle, Mohave and Coconino Counties, Northwestern Arizona

    USGS Publications Warehouse

    Billingsley, George H.; Wellmeyer, Jessica L.

    2003-01-01

    The geologic map of the Mount Trumbull 30' x 60' quadrangle is a cooperative product of the U.S. Geological Survey, the National Park Service, and the Bureau of Land Management that provides geologic map coverage and regional geologic information for visitor services and resource management of Grand Canyon National Park, Lake Mead Recreational Area, and Grand Canyon Parashant National Monument, Arizona. This map is a compilation of previous and new geologic mapping that encompasses the Mount Trumbull 30' x 60' quadrangle of Arizona. This digital database, a compilation of previous and new geologic mapping, contains geologic data used to produce the 100,000-scale Geologic Map of the Mount Trumbull 30' x 60' Quadrangle, Mohave and Coconino Counties, Northwestern Arizona. The geologic features that were mapped as part of this project include: geologic contacts and faults, bedrock and surficial geologic units, structural data, fold axes, karst features, mines, and volcanic features. This map was produced using 1:24,000-scale 1976 infrared aerial photographs followed by extensive field checking. Volcanic rocks were mapped as separate units when identified on aerial photographs as mappable and distinctly separate units associated with one or more pyroclastic cones and flows. Many of the Quaternary alluvial deposits that have similar lithology but different geomorphic characteristics were mapped almost entirely by photogeologic methods. Stratigraphic position and amount of erosional degradation were used to determine relative ages of alluvial deposits having similar lithologies. Each map unit and structure was investigated in detail in the field to ensure accuracy of description. Punch-registered mylar sheets were scanned at the Flagstaff Field Center using an Optronics 5040 raster scanner at a resolution of 50 microns (508 dpi). The scans were output in .rle format, converted to .rlc, and then converted to ARC/INFO grids. A tic file was created in geographic coordinates

  12. Rapid response of alpine timberline vegetation to the Younger Dryas climate oscillation in the Colorado Rocky Mountains, USA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reasoner, M.A.; Jodry, M.A.

    2000-01-01

    Paleobotanical records from two high-altitude (>3,300 m) sites in Colorado show a clear and immediate response to the Younger Dryas climate oscillation. The Black Mountain Lake and Sky Pond records indicate that alpine timberline migrated upslope to near-modern elevations during the late Bolling-Allerod (13.6--12.9 ka). Subsequent declines in arboreal pollen percentages and accumulation rates during the Younger Dryas interval (12.9--11.7 ka) reflect a downslope displacement of the alpine timberline ecotone of 60--120 m in elevation. This change translates to a cooling of summer temperature by {approximately}0.4--0.9 C and is consistent with proposed Younger Dryas advances of alpine glaciers in themore » Rocky Mountains to positions close to Little Ice Age maxima. Alpine timberline readvanced upslope to elevations above both sites between 11.7 and 11.4 ka. The concomitant response of temperature-sensitive alpine timberline vegetation in Colorado and late-glacial changes in North Atlantic thermohaline circulating implicates a rapid, widespread atmospheric transmission of the Younger Dryas climate oscillation.« less

  13. Climatic significance of the bristlecone pine latewood frost-ring record at Almagre Mountain, Colorado, U.S.A.

    USGS Publications Warehouse

    Brunstein, F. Craig

    1996-01-01

    From 1900 to 1993, latewood frost rings occurred in 1903, 1912, 1941, 1961, and 1965 in 10 to 21% of the sampled bristlecone pines at Almagre Mountain, Colorado. In early to mid September in each of those years, a severe outbreak of unseasonably cold air from higher latitudes produced a memorable or historic late-summer snowstorm in the western United States. Record subfreezing temperatures during these snowstorms probably caused the latewood frost rings, shortened (by about 1 mo in 1912) already colder than normal growing seasons, and caused crop damage in parts of the Western United States. Latewood frost rings recorded in relatively high percentages of the sampled trees (such as the 1805 event in 61% of sampled trees) were probably caused by multiple severe outbreaks of unseasonably cold air from higher latitudes that occurred from early September (possibly as early as mid- or late August) to mid-September. Analyses of 1900-1992 temperature data for two widely separated Colorado stations, Fort Collins and Colorado Springs, show that average summer (June-September) temperatures during latewood frost-ring years in this century were 1.5 and 2.0°C cooler than normal, respectively. Mountain snowpack probably persisted through these cool summers and was subsequently buried by the earlier than normal snowfall in September. Latewood frost-ring, ring-width, historical, and other data suggest that severe to cataclysmic volcanic eruptions from 1812 to 1835 triggered (1) an extended period of climatic cooling from as early as 1816 or 1817 through the early 1850s in the Southern Rocky Mountains, (2) catastrophic winters in Colorado and Wyoming in 1842-43 and 1844-45, and in the Great Salt Lake Basin in 1836-37, that caused large-scale destruction of bison and other large plains animals, and (3) Little Ice Age alpine glacial advances in about 1850-60 in the western United States.

  14. Eastern Colorado mobility study : final report

    DOT National Transportation Integrated Search

    2002-04-01

    Colorado, with an economy based in large part on agriculture, has a need to transport large quantities of commodities. The rapidly growing urban areas in the state also need many products and goods to support the growth. Furthermore, Colorado is stra...

  15. Algal Data from Selected Sites in the Upper Colorado River Basin, Colorado, Water Years 1996-97

    USGS Publications Warehouse

    Mize, Scott V.; Deacon, Jeffrey R.

    2001-01-01

    Algal community samples were collected at 15 sites in the Upper Colorado River Basin in Colorado as part of the National Water-Quality Assessment Program during water years 1996-97. Sites sampled were located in two physiographic provinces, the Southern Rocky Mountains and the Colorado Plateaus, and represented agricultural, mining, urban, and mixed land uses and background conditions. Algal samples were collected once per year during low-flow conditions. Quantitative algal samples were collected within two targeted instream habitat types including a taxonomically richest-targeted habitat and a depositional-targeted habitat. This report presents the algal community data collected at the fixed sites in the Upper Colorado River Basin study unit. Algal data include densities (abundance of cells per square centimeter of substrate) and biovolumes (cubic micrometers of cells per square centimeter of substrate) for the two habitat types. Quality-assurance and quality-control results for algal samples indicate that the largest sampling variability tends to occur in samples from small streams.

  16. Detailed cross sections of the Eocene Green River Formation along the north and east margins of the Piceance Basin, western Colorado, using measured sections and drill hole information

    USGS Publications Warehouse

    Johnson, Ronald C.

    2014-01-01

    This report presents two detailed cross sections of the Eocene Green River Formation in the Piceance Basin, northwestern Colorado, constructed from eight detailed measured sections, fourteen core holes, and two rotary holes. The Eocene Green River Formation in the Piceance Basin contains the world’s largest known oil shale deposit with more than 1.5 billion barrels of oil in place. It was deposited in Lake Uinta, a long-lived saline lake that once covered much of the Piceance Basin and the Uinta Basin to the west. The cross sections extend across the northern and eastern margins of the Piceance Basin and are intended to aid in correlating between surface sections and the subsurface in the basin.

  17. Colorado Model Content Standards: Science

    ERIC Educational Resources Information Center

    Colorado Department of Education, 2007

    2007-01-01

    The Colorado Model Content Standards for Science specify what all students should know and be able to do in science as a result of their school studies. Specific expectations are given for students completing grades K-2, 3-5, 6-8, and 9-12. Five standards outline the essential level of science knowledge and skills needed by Colorado citizens to…

  18. 77 FR 23498 - Notice of Intent To Repatriate Cultural Items: The Colorado College, Colorado Springs, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ... Taylor Museum and the Colorado Springs Fine Arts Center) and the Denver Museum of Nature & Science... Davis, Chief of Staff, President's Office, Colorado College, Armstrong Hall, Room 201, 14 E. Cache La... objects, as well as other cultural items were removed from Canyon de Chelly, Apache County, AZ, under the...

  19. Seismicity of the Colorado Lineament

    NASA Astrophysics Data System (ADS)

    Brill, Kenneth G., Jr.; Nuttli, Otto W.

    1983-01-01

    The Colorado Lineament appears to be one of the source zones for the larger earthquakes of the west-central United States. As defined by Warner (1975), the lineament trends northeastward from northwestern Arizona to central Minnesota. Numerous Precambrian trends have been recognized along the lineament; some are reflected in the overlying strata. Mineralized areas such as the Colorado Mineral Belt, the Hartville iron deposits of Wyoming, and the Cuyuna Iron Range of Minnesota are associated with the lineament, which may represent a Precambrian continental plate boundary in the form of a wrench fault system (Warner, 1978). Between 1860 and 1875 about 18 earthquakes with epicentral intensity greater than or equal to VI and felt area greater than 25,000 km2 (10,000 mi2; equivalently a body-wave magnitude ges;4.5) had epicenters within the surface projection of the Colorado Lineament. All but a few of the remaining west-central earthquakes of this size can be associated with the Nemaha uplift, the Rio Grande Rift, the Wichita Mountain uplift and the Overthrust Belt. Although these latter structures have previously been recognized as source zones for larger earthquakes, the Colorado Lineament had not been so recognized.

  20. The Economic Costs of a Shrinking Lake Mead: a Spatial Hedonic Analysis

    NASA Astrophysics Data System (ADS)

    Singh, A.; Saphores, J. D.

    2017-12-01

    Persistent arid conditions and population growth in the Southwest have taken a toll on the Colorado River. This has led to substantial drawdowns of many water reservoirs around the Southwest, and especially of Lake Mead, which is Las Vegas' main source of drinking water. Due to its importance, Lake Mead has received a great deal of media attention about its "bathtub ring" and the exposure of rock that used to be underwater. Drops in water levels have caused some local marinas to close, thereby affecting the aesthetic and recreational value of Lake Mead, which is located in the country's largest National Recreation Area (NRA), and surrounded by protected land. Although a rich literature analyzes how water quality impacts real estate values, relatively few studies have examined how dropping water levels are capitalized in surrounding residential properties. In this context, the goal of this study is to quantify how Lake Mead's water level changes are reflected in changes in local property values, an important source of tax income for any community. Since Lake Mead is the primary attraction within its recreation area, we are also concerned with how this recreation area, which is a few miles southeast of Las Vegas, is capitalized in real estate values of the Las Vegas metropolitan area as few valuation studies have examined how proximity to national parks influences residential property value. We estimate spatial hedonic and geographically weighted regression models of single family residences to delineate the value of proximity to the Lake Mead NRA and to understand how this value changed with Lake Mead's water levels. Our explanatory variables include common structural characteristics, fixed effects to account for unobserved locally constant characteristics, and specific variables such as distance to the Las Vegas strip and to downtown casinos. Because the sharpest declines in Lake Mead water levels happened in 2010 (NASA, 2010) and winter 2016 saw an unexpected

  1. Colorado River campsite monitoring, Grand Canyon National Park, Arizona, 1998-2012

    USGS Publications Warehouse

    Kaplinski, Matt; Hazel, Joe; Parnell, Rod; Hadley, Daniel R.; Grams, Paul

    2014-01-01

    River rafting trips and hikers use sandbars along the Colorado River in Marble and Grand Canyons as campsites. The U.S. Geological Survey evaluated the effects of Glen Canyon Dam operations on campsite areas on sandbars along the Colorado River in Grand Canyon National Park. Campsite area was measured annually from 1998 to 2012 at 37 study sites between Lees Ferry and Diamond Creek, Arizona. The primary purpose of this report is to present the methods and results of the project. Campsite area surveys were conducted using total station survey methods to outline the perimeter of camping area at each study site. Campsite area is defined as any region of smooth substrate (most commonly sand) with no more than an 8 degree slope and little or no vegetation. We used this definition, but relaxed the slope criteria to include steeper areas near boat mooring locations where campers typically establish their kitchens. The results show that campsite area decreased over the course of the study period, but at a rate that varied by elevation zone and by survey period. Time-series plots show that from 1998 to 2012, high stage-elevation (greater than the 25,000 ft3/s stage-elevation) campsite area decreased significantly, although there was no significant trend in low stage-elevation (15,000–20,000 ft3/s) campsite area. High stage-elevation campsite area increased after the 2004 and 2008 high flows, but decreased in the intervals between high flows. Although no overall trend was detected for low stage-elevation campsite areas, they did increase after high-volume dam releases equal to or greater than about 20,000 ft3/s. We conclude that dam operations have not met the management objectives of the Glen Canyon Adaptive Management program to increase the size of camping beaches in critical and non-critical reaches of the Colorado River between Glen Canyon Dam and Lake Mead.

  2. Powassan encephalitis and Colorado tick fever.

    PubMed

    Romero, José R; Simonsen, Kari A

    2008-09-01

    This article discusses two tick-borne illnesses: Powassan encephalitis, a rare cause of central nervous system infection caused by the Powassan virus, and Colorado tick fever, an acute febrile illness caused by the Colorado tick fever virus common to the Rocky Mountain region of North America.

  3. Barriers to Enrollment in Health Coverage in Colorado.

    PubMed

    Martin, Laurie T; Bharmal, Nazleen; Blanchard, Janice C; Harvey, Melody; Williams, Malcolm

    2015-03-20

    As part of the implementation of the Affordable Care Act, Colorado has expanded Medicaid and also now operates its own health insurance exchange for individuals (called Connect for Health Colorado). As of early 2014, more than 300,000 Coloradans have newly enrolled in Medicaid or health insurance through Connect for Health Colorado, but there also continues to be a diverse mix of individuals in Colorado who remain eligible for but not enrolled in either private insurance or Medicaid. The Colorado Health Foundation commissioned the RAND Corporation to conduct a study to better understand why these individuals are not enrolled in health insurance coverage and to develop recommendations for how Colorado can strengthen its outreach and enrollment efforts during the next open enrollment period, which starts in November 2014. RAND conducted focus groups with uninsured and newly insured individuals across the state and interviews with local stakeholders responsible for enrollment efforts in their regions. The authors identified 11 commonly cited barriers, as well as several that were specific to certain regions or populations (such as young adults and seasonal workers). Collectively, these barriers point to a set of four priority recommendations that stakeholders in Colorado may wish to consider: (1) Support and expand localized outreach and tailored messaging; (2) Strengthen marketing and messaging to be clear, focused on health benefits of insurance (rather than politics and mandates), and actionable; (3) Improve the clarity and transparency of insurance and health care costs and enrollment procedures; and (4) Revisit the two-stage enrollment process and improve Connect for Health Colorado website navigation and technical support.

  4. 36 CFR 294.49 - List of designated Colorado Roadless Areas.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false List of designated Colorado... AGRICULTURE SPECIAL AREAS Colorado Roadless Area Management § 294.49 List of designated Colorado Roadless Areas. All National Forest System lands within the State of Colorado listed in this section are hereby...

  5. 36 CFR 294.49 - List of designated Colorado Roadless Areas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false List of designated Colorado... AGRICULTURE SPECIAL AREAS Colorado Roadless Area Management § 294.49 List of designated Colorado Roadless Areas. All National Forest System lands within the State of Colorado listed in this section are hereby...

  6. Characteristics and trends of streamflow and dissolved solids in the upper Colorado River Basin, Arizona, Colorado, New Mexico, Utah, and Wyoming

    USGS Publications Warehouse

    Liebermann, Timothy D.; Mueller, David K.; Kircher, James E.; Choquette, Anne F.

    1989-01-01

    Annual and monthly concentrations and loads of dissolved solids and major constituents were estimated for 70 streamflow-gaging stations in the Upper Colorado River Basin. Trends in streamflow, dissolved-solids concentrations, and dissolved-solids loads were identified. Nonparametric trend-analysis techniques were used to determine step trends resulting from human activities upstream and long-term monotonic trends. Results were compared with physical characteristics of the basin and historical water-resource development in the basin to determine source areas of dissolved solids and possible cause of trends. Mean annual dissolved-solids concentration increases from less than 100 milligrams per liter in the headwater streams to more than 500 milligrams per liter in the outflow from the Upper Colorado River Basin. All the major tributaries that have high concentrations of dissolved solids are downstream from extensive areas of irrigated agriculture. However, irrigation predated the period of record for most sites and was not a factor in many identified trends. Significant annual trends were identified for 30 sites. Most of these trends were related to transbasin exports, changes in land use, salinity-control practices, or reservoir development. The primary factor affecting streamflow and dissolved-solids concentration and load has been the construction of large reservoirs. Reservoirs have decreased the seasonal and annual variability of streamflow and dissolved solids in streams that drain the Gunnison and San Juan River basins. Fontenelle and Flaming Gorge Reservoirs have increased the dissolved-solids load in the Green River because of dissolution of mineral salts from the bank material. The largest trends occurred downstream from Lake Powell. However, the period of record since the completion of filling was too short to estimate the long-term effects of that reservoir.

  7. Sediment Transport in the Bill Williams River and Turbidity in Lake Havasu During and Following Two High Releases from Alamo Dam, Arizona, in 2005 and 2006

    USGS Publications Warehouse

    Wiele, Stephen M.; Hart, Robert J.; Darling, Hugh L.; Hautzinger, Andrew B.

    2009-01-01

    Discharges higher than are typically released from Alamo Dam in west-central Arizona were planned and released in 2005, 2006, 2007, and 2008 to study the effects of these releases on the Bill Williams River and Lake Havasu, into which the river debouches. Sediment concentrations and water discharges were measured in the Bill Williams River, and turbidity, temperature, and dissolved oxygen were measured in Lake Havasu during and after experimental releases in 2005 and 2006 from Alamo Dam. Data from such releases will support ongoing ecological studies, improve environmentally sensitive management of the river corridor, and support the development of a predictive relationship between the operation of Alamo Dam and downstream flows and their impact on Lake Havasu and the Colorado River. Elevated discharges in the Bill Williams River mobilize more sediment than during more typical dam operation and can generate a turbidity plume in Lake Havasu. The intakes for the Central Arizona Project, which transfers Colorado River water to central and southern Arizona, are near the mouth of the Bill Williams River. Measurement of the turbidity and the development of the plume over time consequently were important components of the study. In this report, the measurements of suspended sediment concentration and discharges in the Bill Williams River and of turbidity in Lake Havasu are presented along with calculations of silt and sand loads in the Bill Williams River. Sediment concentrations were varied and likely dependent on a variable supply. Sediment loads were calculated at the mouth of the river and near Planet, about 10 km upstream from the mouth for the 2005 release, and they indicate that a net increase in transport of silt and a net decrease in the transport of sand occurred in the reach between the two sites.

  8. Abrupt lake-level changes in the Rocky Mountains and surrounding regions since the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Shuman, B. N.; Serravezza, M.

    2016-12-01

    The paleohydrologic record of western North America since the last glacial maximum reveals a wide range of hydroclimatic variability and distinctive patterns associated with abrupt climate changes. To evaluate the sequence of abrupt hydroclimatic shifts and centennial-to-millennial hydrologic variability in western North America over the past 17 ka, we reconstruct lake-level histories from two high-elevation lakes in the Beartooth and Bighorn Mountains. The lakes represent the headwaters of the Missouri River drainage in northern Wyoming, but also have the potential to capture regional hydroclimate variability that links the northern Rocky Mountains to the mid-continent, Pacific Northwest, and the Great Basin. We first discuss the stratigraphic record of lake-level changes in small mid-latitude lakes and then use ground-penetrating radar (GPR) and sediment cores to track the elevations of shoreline sediments within the lakes through time. We compare the stratigraphies to the records from four other lakes in Wyoming and Colorado, and find widespread evidence for a Terminal Pleistocene Drought from 15-11 ka, an early Holocene humid period from 11-8 ka, and a period of severe mid-Holocene aridity from 8-5.7 ka. The northern Wyoming lakes also provide evidence of high levels before ca. 15 ka, including rapid hydroclimatic changes at ca. 16.8 ka during Heinrich Event 1. We place the changes in a broad context by summarizing and mapping water-level changes from 107 additional, previously studied lakes. Important patterns include 1) extensive drying across the western U.S. after 15 ka; 2) coherent sub-regional differences during the Younger Dryas and Pleistocene-Holocene transition; 3) a north-south contrast from 9-6 ka consistent with a northward shift in storm tracks as the influence of the Laurentide Ice Sheet diminished; and 4) rapid increases in effective moisture across much of western North America from 6-4 ka.

  9. 9. INTAKE STREAM ON GROUND LOOKING WEST AS IT FLOWS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. INTAKE STREAM ON GROUND LOOKING WEST AS IT FLOWS DOWNSTREAM TO LAKE MATHEWS, ALL WATER COMING FROM PUMPS. - Colorado River Aqueduct, From Colorado River to Lake Mathews, Parker Dam, San Bernardino County, CA

  10. Clastic pipe characteristics and distributions throughout the Colorado Plateau: Implications for paleoenvironment and paleoseismic controls

    NASA Astrophysics Data System (ADS)

    Wheatley, D. F.; Chan, M. A.; Sprinkel, D. A.

    2016-10-01

    Clastic pipes occur throughout much of the Phanerozoic strata of the Colorado Plateau and provide a unique opportunity to test the validly of various deformation and triggering mechanism hypotheses in the context of their tectono-stratigraphic and paleoenvironmental settings. Pipes dominantly occur in Jurassic strata and preferentially in eolian (especially interdune), sabkha, and fluvial deposits because these sediments contained interbedded fine-grained and water-saturated, high-porosity, coarse-grained facies. The greatest geographic concentrations of pipes occur in three trends: (1) a northeast trend from the Lake Powell to Moab areas of southern and southeastern Utah, (2) an east-west trend in northern Arizona within and north of the Grand Canyon, and (3) a west-northwest-east-southeast trend along Interstate 40 west of Albuquerque, New Mexico. Many pipes formed due to liquefaction and fluidization and were potentially triggered by seismic activity originating from basement-cored uplifts within the Colorado Plateau, although other trigger mechanisms cannot be completely eliminated. Some breccia pipes within northern Arizona that are rooted in karst are the exception to this interpretation. Pipes possess unique depositional and triggering requirements and thus provide an excellent opportunity to understand the interplay of sedimentology and tectonics within continental systems.

  11. Educator Preparation in Colorado, 1995-96.

    ERIC Educational Resources Information Center

    Colorado State Dept. of Education, Denver.

    This report provides data on teacher education and certification in Colorado in the following formats: (1) the number of students in each of the 16 Colorado institutions of higher education approved for educator preparation programs who were recommended for licensure and endorsements during 1995-1996 (total 2517); (2) the numbers of students…

  12. Sources of acid and metals from the weathering of the Dinero waste pile, Lake Fork watershed, Leadville, Colorado

    USGS Publications Warehouse

    Diehl, S.F.; Hageman, Phil L.; Smith, Kathleen S.; Herron, J.T.; Desborough, G.A.

    2005-01-01

    Two trenches were dug into the south Dinero mine-waste pile near Leadville, Colorado, to study the weathering of rock fragments and the mineralogic sources of metal contaminants in the surrounding wetland and Lake Fork Watershed. Water seeping from the base of the south Dinero waste-rock pile was pH 2.9, whereas leachate from a composite sample of the rock waste was pH 3.3. The waste pile was mostly devoid of vegetation, open to infiltration of precipitation, and saturated at the base because of placement in the wetland. The south mine-waste pile is composed of poorly sorted material, ranging from boulder-size to fine-grained rock fragments. The trenches showed both matrix-supported and clast-supported zones, with faint horizontal color banding, suggesting zonation of Fe oxides. Secondary minerals such as jarosite and gypsum occurred throughout the depth of the trenches. Infiltration of water and transport of dissolved material through the pile is evidenced by optically continuous secondary mineral deposits that fill or line voids. Iron-sulfate material exhibits microlaminations with shrinkage cracking and preferential dissolution of microlayers that evidence drying and wetting events. In addition to fluids, submicron-sized to very fine-grained particles such as jarosite are transported through channel ways in the pile. Rock fragments are coated with a mixture of clay, jarosite, and manganese oxides. Dissolution of minerals is a primary source of metals. Skeletal remnants of grains, outlined by Fe-oxide minerals, are common. Potassium jarosite is the most abundant jarosite phase, but Pb-and Ag-bearing jarosite are common. Grain-sized clusters of jarosite suggest that entire sulfide grains were replaced by very fine-grained jarosite crystals. The waste piles were removed from the wetland and reclaimed upslope in 2003. This was an opportunity to test methods to identify sources of acid and metals and metal transport processes within a waste pile. A series of

  13. NASA Helps Build Colorado Economy

    NASA Image and Video Library

    2010-12-13

    NASA Deputy Administrator Lori Garver delivers remarks at the Colorado State Capitol in Denver on Monday, Dec. 13, 2010, prior to signing an agreement that creates a Technology Acceleration Program and Regional Innovation Cluster for Aerospace and Clean Energy. A manufacturing park focused on rapid new product development and production will be developed to assist growing Colorado businesses while promoting the commercialization of technology developed for the space program. Photo Credit: (NASA/Bill Ingalls)

  14. Colorado: Youth Risk Behavior Survey, 1991.

    ERIC Educational Resources Information Center

    Colorado Univ. Health Sciences Center, Denver.

    In April 1991, the Youth Risk Behavior Survey was administered to a sample of 1,412 high school students in Colorado public schools to collect information about priority health-risk behaviors among adolescents. Questionnaires were received from 1,170 students, a response rate of 83%. Classes in Colorado's 280 public schools were also selected to…

  15. 77 FR 50712 - Notice of Filing of Plats; Colorado.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats; Colorado. AGENCY: Bureau of Land Management, Interior. ACTION: Notice of filing of plats; Colorado. SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is publishing this notice to...

  16. Sudden aspen decline in southwest Colorado

    Treesearch

    J. J. Worrall; R. A. Mask; T. Eager; L. Egeland; W. D. Shepperd

    2008-01-01

    Sudden aspen decline (SAD) has increased rapidly in recent years, approaching 350,000 acres in Colorado in 2007, or 13% of the aspen cover type. We investigated the severity, site/stand factors and causes associated with SAD in southwest Colorado. First, we documented landscape (GIS-DEM analyses) and stand factors (stand exams). There was a strong inverse relationship...

  17. Intrusive rocks northeast of Steamboat Springs, Park Range, Colorado, with a section on geochronology

    USGS Publications Warehouse

    Snyder, George L.; Hedge, Carl E.

    1978-01-01

    Major Precambrian and minor Tertiary intrusive rocks northeast of Steamboat Springs in the Park Range between 40?30' and 40?45' N. lat. are described and compared with related rocks elsewhere in Colorado and Wyoming. The Precambrian intrusives were emplaced in a sequence of high-grade interlayered felsic gneisses, amphibolites, and pelitic schists of sedimentary and volcanic origin. These rocks are cut by a major northeast-trending Precambrian shear zone where mainly left lateral movement of 1/ 2 to 1 mile is certain. Cumulative movement of many miles is possible. The Precambrian intrusives consist of a batholith, the Mount Ethel pluton, a smaller Buffalo Pass pluton, and small dikes or lenses of fine-grained porphyry, pegmatites, and ultramafics. The Mount Ethel pluton is an oval shaped body 7 miles wide by about 40 miles long (shown by geophysical data to extend beneath younger sediments in North Park). Outer batholithic contacts are sharp and dip steeply outward at about 85?. Five mappable internal variants consist, in order of decreasing age, of granodiorite, quartz monzonite porphyry of Rocky Peak, quartz monzonite of Roxy Ann Lake, granite and quartz monzonite, and. leucogranite. Internal contacts between these plutonic variants are sharp, and evidence of liquid-solid relationships abounds; despite this, all rocks except the granodiorite contribute to an Rb-Sr whole-rock isochron indicating emplacement about 1.4 b.y. (billion years) ago. The most important variants volumetrically are: the quartz monzonite porphyry of Rocky Peak, which forms an irregular 2-mile-thick carapace or mapped band around the west edge of the pluton and is lithologically similar to nearby Sherman Granite, and the quartz monzonite of Roxy Ann Lake, which forms most of the rest of the pluton and is lithologically similar to Silver Plume Granite. An apparent Sherman -Silver Plume dichotomy with similar rock types and similar relative ages is noted throughout Colorado plutons of that age

  18. 77 FR 9840 - Amendment of Class E Airspace; Colorado Springs, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-21

    ...-1191; Airspace Docket No. 11-ANM-21] Amendment of Class E Airspace; Colorado Springs, CO AGENCY... airspace at City of Colorado Springs Municipal Airport, Colorado Springs, CO. Decommissioning of the Black... controlled airspace at Colorado Springs, CO (76 FR 70920). Interested parties were invited to participate in...

  19. Statistics & Input-Output Measures for Colorado Public Libraries, 1999.

    ERIC Educational Resources Information Center

    Colorado State Dept. of Education, Denver. State Library and Adult Education Office.

    "Statistics and Input-Output Measures for Colorado Public Libraries, 1999" is a compilation of data collected from the Colorado Public Library Annual Report sent to each public library jurisdiction in February of 2000 and returned in March. The 1999 response rate was excellent: 100% of Colorado public libraries returned the Annual Report…

  20. Intake Procedures in Colorado Animal Shelters

    PubMed Central

    Fagre, Anna; Olea-Popelka, Francisco; Ruch-Gallie, Rebecca

    2017-01-01

    Simple Summary Many animal shelters receive animals from different regions of the United States; particularly following natural disasters or other mass displacements. After Hurricane Katrina; Colorado experienced a surge of animal intakes from regions of the country possessing higher parasitic burden. Little is known about the extent to which shelters tailor their infectious disease screening procedures and other intake protocols based on animal origin. Using a questionnaire; shelter personnel from across the state of Colorado provided information on shelter characteristics including where they receive animals from; general intake procedures; and perceptions on infectious disease risk. We found that more shelters that take dogs in from out of state screen for heartworm and other parasitic diseases than do shelters that only take animals from within the state. No difference was seen for feline screening procedures. We also found that few shelters use widespread screening protocols and instead screen based on suspicion. Lastly; many vaccination protocols in shelters do not comply with The Association of Shelter Veterinarians Guidelines for Standards of Care in Animal Shelters. This study highlights the importance of tailoring animal intake procedures based on where the animal was transferred from. Abstract The purpose of this study was to describe intake procedures in Colorado animal shelters, compare infectious disease screening protocols in shelters taking in animals from out-of-state to shelters only accepting animals from Colorado, and analyze perceived risk of diseases in Colorado by responding shelter personnel. A questionnaire was designed and administered to shelter personnel across the state of Colorado via the survey tool SurveyMonkey© (http://www.surveymonkey.com) or a mailed hard copy. Information collected concerned general shelter characteristics and intake procedures performed in various circumstances as reported by responding shelter personnel. Only

  1. Space Radar Image of Colorado River

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This space radar image illustrates the recent rapid urban development occurring along the lower Colorado River at the Nevada/Arizona state line. Lake Mojave is the dark feature that occupies the river valley in the upper half of the image. The lake is actually a reservoir created behind Davis Dam, the bright white line spanning the river near the center of the image. The dam, completed in 1953, is used both for generating electric power and regulating the river's flow downstream. Straddling the river south of Davis Dam, shown in white and bright green, are the cities of Laughlin, Nevada (west of the river) and Bullhead City, Arizona (east of the river). The runway of the Laughlin, Bullhead City Airport is visible as a dark strip just east of Bullhead City. The area has experienced rapid growth associated with the gambling industry in Laughlin and on the Fort Mojave Indian Reservation to the south. The community of Riviera is the bright green area in a large bend of the river in the lower left part of the image. Complex drainage patterns and canyons are the dark lines seen throughout the image. Radar is a useful tool for studying these patterns because of the instrument's sensitivity to roughness, vegetation and subtle topographic differences. This image is 50 kilometers by 35 kilometers (31 miles by 22 miles) and is centered at 35.25 degrees north latitude, 114.67 degrees west longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and vertically received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 13, 1994, onboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Office of

  2. Colorado Department of Education Abbreviated Information Management Annual Plan (CDE IMAP).

    ERIC Educational Resources Information Center

    Laughlin, Richard

    The Colorado Department of Education (CDE), including Access Colorado Library and Information Network (ACLIN) and the Colorado School for the Deaf and the Blind, provides state- level guidance and resources for Colorado's local school districts, local and regional libraries, and special populations. Technology is the enabler that offers basic,…

  3. 78 FR 52600 - Colorado Disaster # CO-00054

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ... SMALL BUSINESS ADMINISTRATION [Disaster Declaration 13718 and 13719] Colorado Disaster CO-00054 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Colorado dated 08/14/2013. Incident: Black Forest Fire...

  4. Evidence of Lake Trout reproduction at Lake Michigan's mid-lake reef complex

    USGS Publications Warehouse

    Janssen, J.; Jude, D.J.; Edsall, T.A.; Paddock, R.W.; Wattrus, N.; Toneys, M.; McKee, P.

    2006-01-01

    The Mid-Lake Reef Complex (MLRC), a large area of deep (> 40 m) reefs, was a major site where indigenous lake trout (Salvelinus namaycush) in Lake Michigan aggregated during spawning. As part of an effort to restore Lake Michigan's lake trout, which were extirpated in the 1950s, yearling lake trout have been released over the MLRC since the mid-1980s and fall gill net censuses began to show large numbers of lake trout in spawning condition beginning about 1999. We report the first evidence of viable egg deposition and successful lake trout fry production at these deep reefs. Because the area's existing bathymetry and habitat were too poorly known for a priori selection of sampling sites, we used hydroacoustics to locate concentrations of large fish in the fall; fish were congregating around slopes and ridges. Subsequent observations via unmanned submersible confirmed the large fish to be lake trout. Our technological objectives were driven by biological objectives of locating where lake trout spawn, where lake trout fry were produced, and what fishes ate lake trout eggs and fry. The unmanned submersibles were equipped with a suction sampler and electroshocker to sample eggs deposited on the reef, draw out and occasionally catch emergent fry, and collect egg predators (slimy sculpin Cottus cognatus). We observed slimy sculpin to eat unusually high numbers of lake trout eggs. Our qualitative approaches are a first step toward quantitative assessments of the importance of lake trout spawning on the MLRC.

  5. Assessing Vulnerability under Uncertainty in the Colorado River Basin: The Colorado River Basin Water Supply and Demand Study

    NASA Astrophysics Data System (ADS)

    Jerla, C.; Adams, P.; Butler, A.; Nowak, K.; Prairie, J. R.

    2013-12-01

    Spanning parts of the seven states, of Arizona, California, Colorado, New Mexico, Nevada, Utah, and Wyoming, the Colorado River is one of the most critical sources of water in the western United States. Colorado River allocations exceed the long-term supply and since the 1950s, there have been a number of years when the annual water use in the Colorado River Basin exceeded the yield. The Basin is entering its second decade of drought conditions which brings challenges that will only be compounded if projections of climate change are realized. It was against this backdrop that the Colorado River Basin Water Supply and Demand Study was conducted. The Study's objectives are to define current and future imbalances in the Basin over the next 50 years and to develop and analyze adaptation and mitigation strategies to resolve those imbalances. Long-term planning in the Basin involves the integration of uncertainty with respect to a changing climate and other uncertainties such as future demand and how policies may be modified to adapt to changing reliability. The Study adopted a scenario planning approach to address this uncertainty in which thousands of scenarios were developed to encompass a wide range of plausible future water supply and demand conditions. Using Reclamation's long-term planning model, the Colorado River Simulation System, the reliability of the system to meet Basin resource needs under these future conditions was projected both with and without additional future adaptation strategies in place. System reliability metrics were developed in order to define system vulnerabilities, the conditions that lead to those vulnerabilities, and sign posts to indicate if the system is approaching a vulnerable state. Options and strategies that reduce these vulnerabilities and improve system reliability were explored through the development of portfolios. Four portfolios, each with different management strategies, were analyzed to assess their effectiveness at

  6. 76 FR 24515 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-02

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Colorado River Basin Salinity Control Advisory... Basin Salinity Control Advisory Council (Council) will meet as detailed below. The meeting of the... INFORMATION: The Colorado River Basin Salinity Control Advisory Council was established by the Colorado River...

  7. The Geologic Story of Colorado National Monument

    USGS Publications Warehouse

    Lohman, Stanley William

    1981-01-01

    From 1946 until about 1956 I carried out fieldwork intermittently on the geology and artesian water supply of the Grand Junction area, Colorado, the results of which have been published. The area mapped geologically contains about 332 square miles in the west-central part of Mesa County and includes all of Colorado National Monument. During the field work several successive custodians or superintendents and several park naturalists urged that upon completion of my professional paper I prepare a brief account of the geology of the Monument in terms understandable by laymen, and which could be sold at the Visitor Center. This I was happy to do and there resulted 'The geologic story of Colorado National Monument', published by the Colorado and Black Canyon Natural History Association in cooperation with the National Park Service. This report contained colored sketches by John R. Stacy and a colored cover, but the photographs and many of the drawings were reproduced in black and white.

  8. 77 FR 41686 - Safety Zone; Sheffield Lake Fireworks, Lake Erie, Sheffield Lake, OH

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-16

    ...-AA00 Safety Zone; Sheffield Lake Fireworks, Lake Erie, Sheffield Lake, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on Lake Erie, Sheffield Lake, OH. This safety zone is intended to restrict vessels from a portion of Lake Erie...

  9. Non-native plant invasions in managed and protected ponderosa pine/douglas-fir forests of the Colorado Front Range

    USGS Publications Warehouse

    Fornwalt, P.J.; Kaufmann, M.R.; Huckaby, L.S.; Stoker, J.M.; Stohlgren, T.J.

    2003-01-01

    We examined patterns of non-native plant diversity in protected and managed ponderosa pine/Douglas-fir forests of the Colorado Front Range. Cheesman Lake, a protected landscape, and Turkey Creek, a managed landscape, appear to have had similar natural disturbance histories prior to European settlement and fire protection during the last century. However, Turkey Creek has experienced logging, grazing, prescribed burning, and recreation since the late 1800s, while Cheesman Lake has not.Using the modified-Whittaker plot design to sample understory species richness and cover, we collected data for 30 0.1 ha plots in each landscape. Topographic position greatly influenced results, while management history did not. At both Cheesman Lake and Turkey Creek, low/riparian plots had highest native and non-native species richness and cover; upland plots (especially east/west-facing, south-facing and flat, high plots) had the lowest. However, there were no significant differences between Cheesman Lake and Turkey Creek for native species richness, native species cover, non-native species richness, or non-native species cover for any topographic category. In general, non-native species richness and cover were highly positively correlated with native species richness and/or cover (among other variables). In total, 16 non-native species were recorded at Cheesman Lake and Turkey Creek; none of the 16 non-native species were more common at one site than another.These findings suggest that: (1) areas that are high in native species diversity also contain more non-native species; (2) both protected and managed areas can be invaded by non-native plant species, and at similar intensities; and (3) logging, grazing, and other similar disturbances may have less of an impact on non-native species establishment and growth than topographic position (i.e., in lowland and riparian zones versus upland zones).

  10. Non-native plant invasions in managed and protected ponderosa pine/Douglas-fir forests of the Colorado Front Range

    USGS Publications Warehouse

    Fornwalt, P.J.; Kaufmann, M.R.; Huckaby, L.S.; Stoker, J.M.; Stohlgren, T.J.

    2003-01-01

    We examined patterns of non-native plant diversity in protected and managed ponderosa pine/Douglas-fir forests of the Colorado Front Range. Cheesman Lake, a protected landscape, and Turkey Creek, a managed landscape, appear to have had similar natural disturbance histories prior to European settlement and fire protection during the last century. However, Turkey Creek has experienced logging, grazing, prescribed burning, and recreation since the late 1800s, while Cheesman Lake has not. Using the modified-Whittaker plot design to sample understory species richness and cover, we collected data for 30 0.1 ha plots in each landscape. Topographic position greatly influenced results, while management history did not. At both Cheesman Lake and Turkey Creek, low/riparian plots had highest native and non-native species richness and cover; upland plots (especially east/west-facing, south-facing and flat, high plots) had the lowest. However, there were no significant differences between Cheesman Lake and Turkey Creek for native species richness, native species cover, non-native species richness, or non-native species cover for any topographic category. In general, non-native species richness and cover were highly positively correlated with native species richness and/or cover (among other variables). In total, 16 non-native species were recorded at Cheesman Lake and Turkey Creek; none of the 16 non-native species were more common at one site than another. These findings suggest that: (1) areas that are high in native species diversity also contain more non-native species; (2) both protected and managed areas can be invaded by non-native plant species, and at similar intensities; and (3) logging, grazing, and other similar disturbances may have less of an impact on non-native species establishment and growth than topographic position (i.e., in lowland and riparian zones versus upland zones).

  11. 78 FR 70574 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-26

    ...] Colorado River Basin Salinity Control Advisory Council AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub. L.93-320) (Act) to...

  12. 76 FR 61382 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Colorado River Basin Salinity Control Advisory...: The Colorado River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub. L. 93-320) (Act) to receive reports and advise Federal...

  13. Mummy Lake: An unroofed ceremonial structure within a large-scale ritual landscape

    USGS Publications Warehouse

    Benson, Larry V.; Griffin, Eleanor R.; Stein, J.R.; Friedman, R. A.; Andrae, S. W.

    2014-01-01

    The structure at Mesa Verde National Park known historically as Mummy Lake and more recently as Far View Reservoir is not part of a water collection, impoundment, or redistribution system. We offer an alternative explanation for the function of Mummy Lake. We suggest that it is an unroofed ceremonial structure, and that it serves as an essential component of a Chacoan ritual landscape. A wide constructed avenue articulates Mummy Lake with Far View House and Pipe Shrine House. The avenue continues southward for approximately 6 km where it apparently divides connecting with Spruce Tree House and Sun Temple/Cliff Palace. The avenue has previously been interpreted as an irrigation ditch fed by water impounded at Mummy Lake; however, it conforms in every respect to alignments described as Chacoan roads. Tree-ring dates indicate that the construction of Spruce Tree House and Cliff Palace began about A.D. 1225, roughly coincident with the abandonment of the Far View community. This pattern of periodically relocating the focus of an Anasazi community by retiring existing ritual structures and linking them to newly constructed facilities by means of broad avenues was first documented by Fowler and Stein (1992) in Manuelito Canyon, New Mexico. Periods of intense drought appear to have contributed to the relocation of prehistoric Native Americans from the Far View group to Cliff Palace/Spruce Tree House in the mid-13th century and eventually to the abandonment of all Anasazi communities in southwestern Colorado in the late-13th century.

  14. NASA Helps Build Colorado Economy

    NASA Image and Video Library

    2010-12-13

    Representative from U.S. Senator Udall's office Jimmy Haugue reads remarks from U.S. Senator Udall at the Colorado State Capitol in Denver on Monday, Dec. 13, 2010, prior to the signing of an agreement with NASA that creates a Technology Acceleration Program and Regional Innovation Cluster for Aerospace and Clean Energy. A manufacturing park focused on rapid new product development and production will be developed to assist growing Colorado businesses while promoting the commercialization of technology developed for the space program. Photo Credit: (NASA/Bill Ingalls)

  15. EPA versus Colorado: national unity versus state flexibility

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Foster, T.

    When the Environmental Protection Agency (EPA) reviewed Colorado's National Pollutant Discharge Elimination System (NPDES) permit program under the federal Clean Water Act, it found a conflict between federal and state perspectives on how much flexibility from national norms is allowable for state peculiarities. Colorado's hydrology and geography seemed to justify a water quality program providing for various opportunities to review water quality decisions before requiring advanced waste treatment (AWT), and to avoid AWT when justified. Conflict arose because few streams in Colorado provide mixing zones or dilution that Eastern streams enjoy. The author reviews the legal developments as EPA arguedmore » for national uniformity and Colorado for flexibility. States might be tempted to return permitting programs to EPA if they cannot retain enough flexibility in the law to protect their interests.« less

  16. Lake trout rehabilitation in Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Eckert, Thomas H.; Schaner, Ted; Bowlby, James N.; Schleen, Larry P.

    1995-01-01

    Attempts to maintain the native lake trout (Salvelinus namaycush) population in Lake Ontario by stocking fry failed and the species was extirpated by the 1950s. Hatchery fish stocked in the 1960s did not live to maturity because of sea lamprey (Petromyzon marinus) predation and incidental commercial harvest. Suppression of sea lampreys began with larvicide treatments of Lake Ontario tributaries in 1971 and was enhanced when the tributaries of Oneida Lake and Lake Erie were treated in the 1980s. Annual stocking of hatchery fish was resumed with the 1972 year class and peaked at about 1.8 million yearlings and 0.3 million fingerlings from the 1985–1990 year classes. Survival of stocked yearlings declined over 50% in the 1980 s and was negatively correlated with the abundance of lake trout > 550 mm long (r = −0.91, P < 0.01, n = 12). A slot length limit imposed by the State of New York for the 1988 fishing season reduced angler harvest. Angler harvest in Canadian waters was 3 times higher in eastern Lake Ontario than in western Lake Ontario. For the 1977–1984 year classes, mean annual survival rate of lake trout age 6 and older was 0.45 (range: 0.35–0.56). In U.S. waters during 1985–1992, the total number of lake trout harvested by anglers was about 2.4 times greater than that killed by sea lampreys. The number of unmarked lake trout < 250 mm long in trawl catches in 1978–1992 was not different from that expected due to loss of marks and failure to apply marks at the hatchery, and suggested that recruitment of naturally-produced fish was nil. However, many of the obstacles which may have impeded lake trout rehabilitation in Lake Ontario during the 1980s are slowly being removed, and there are signs of a general ecosystem recovery. Significant recruitment of naturally produced lake trout by the year 2000, one interim objective of the rehabilitation plan for the Lake, may be achieved.

  17. Lake level variability in Silver Lake, Michigan: a response to fluctuations in lake levels of Lake Michigan

    USGS Publications Warehouse

    Fisher, Timothy G.; Loope, Walter L.

    2004-01-01

    Sediment from Silver Lake, Michigan, can be used to constrain the timing and elevation of Lake Michigan during the Nipissing transgression. Silver Lake is separated from Lake Michigan by a barrier/dune complex and the Nipissing, Calumet, and Glenwood shorelines of Lake Michigan are expressed landward of this barrier. Two Vibracores were taken from the lake in February 2000 and contain pebbly sand, sand, buried soils, marl, peat, and sandy muck. It is suggested here that fluctuations in the level of Lake Michigan are reflected in Silver Lake since the Chippewa low phase, and possibly at the end of the Algonquin phase. An age of 12,490 B.P. (10,460±50 14C yrs B.P.) on wood from a buried Entisol may record the falling Algonquin phase as the North Bay outlet opened. A local perched water table is indicated by marl deposited before 7,800 B.P. and peat between 7,760-7,000 B.P. when Lake Michigan was at the low elevation Chippewa phase. Continued deepening of the lake is recorded by the transition from peat to sandy muck at 7,000 B.P. in the deeper core, and with the drowning of an Inceptisol nearly 3 m higher at 6,410 B.P. in the shallower core. A rising groundwater table responding to a rising Lake Michigan base level during the Nipissing transgression, rather than a response to mid-Holocene climate change, explains deepening of Silver Lake. Sandy muck was deposited continually in Silver Lake between Nipissing and modern time. Sand lenses within the muck are presumed to be eolian in origin, derived from sand dunes advancing into the lake on the western side of the basin.

  18. Resistivity sections, upper Arkansas River basin, Colorado

    USGS Publications Warehouse

    Zohdy, Adel A.R.; Hershey, Lloyd A.; Emery, Philip A.; Stanley, William D.

    1971-01-01

    A reconnaissance investigation of ground-water resources in the upper Arkansas River basin from Pueblo to Leadville is being made by the U.S. Geological Survey in cooperation with the Southeastern Colorado Water Conservancy District, and the Colorado Division of Water Resources, Colorado State Engineer. As part of the investigation, surface geophysical electrical resistivity surveys were made during the summer and fall of 1970 near Buena Vista and Westcliffe, Colo. (p1.1). The resistivity surveys were made to verify a previous gravity survey and to help locate areas where ground-water supplies might be developed. This report presents the results of the surveys in the form of two resistivity sections.

  19. Conservation status of Colorado River cutthroat trout

    Treesearch

    Michael K. Young; R. Nick Schmal; Thomas W. Kohley; Victoria G. Leonard

    1996-01-01

    Though biologists recognize that populations of Colorado River cutthroat trout have declined, the magnitude of the loss remains unquantified. We obtained information from state and federal biologists and from state databases to determine the current distribution and status of populations of Colorado River cutthroat trout. Recent population extinctions have been...

  20. Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

    PubMed

    Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

    2016-06-01

    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Quality of life on the Colorado Plateau: a report to the respondents in southwestern Colorado and northwestern New Mexico

    USGS Publications Warehouse

    Ponds, Phadrea

    2001-01-01

    During the fall of 1998, scientists from the Midcontinent Ecological Science Center (MESC) of the U.S. Geological Survey (USGS) a?? sent a survey by mail to residents in southwest Colorado and northwest New Mexico to better understand quality of life issues in this area of the Colorado Plateau. Collaborators in this study included the Bureau of Land Management and U.S. Forest Service offices located in Durango, Colorado. The information was collected to determine: *what elements of the community and surrounding landscapes contribute to the quality of like among resident populations, and *what critical areas, elements, and special places are essential to retain quality of life.

  2. 2013 Kids Count in Colorado! Community Matters

    ERIC Educational Resources Information Center

    Colorado Children's Campaign, 2013

    2013-01-01

    "Kids Count in Colorado!" is an annual publication of the Children's Campaign, providing state and county level data on child well-being factors including child health, education, and economic status. Since its first release 20 years ago, "Kids Count in Colorado!" has become the most trusted source for data and information on…

  3. Salt Lake City Area Integrated Projects Electric Power Marketing. Draft environmental impact statement: Volume 4, Appendixes B-D

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    1994-02-01

    The Salt Lake City Area Office of the Western Area Power Administration (Western) markets electricity produced at hydroelectric facilities operated by the Bureau of Reclamation. The facilities are known collectively as the Salt Lake City Area Integrated Projects (SLCA/IP) and include dams equipped for power generation on the Green, Gunnison, Rio Grande, and Colorado rivers and on Deer and Plateau creeks in the states of Wyoming, Utah, Colorado, Arizona, and New Mexico. Of these facilities, only the Glen Canyon Unit, the Flaming Gorge Unit, and the Aspinall Unit (which includes Blue Mesa, Morrow Point, and Crystal dams;) are influenced bymore » Western power scheduling and transmission decisions. The EIS alternatives, called commitment-level alternatives, reflect combinations of capacity and energy that would feasibly and reasonably fulfill Westerns firm power marketing responsibilities, needs, and statutory obligations. The viability of these alternatives relates directly to the combination of generation capability of the SLCA/IP with energy purchases and interchange. The economic and natural resource assessments in this environmental impact statement (EIS) include an analysis of commitment-level alternatives. Impacts of the no-action alternative are also assessed. Supply options, which include combinations of electrical power purchases and hydropower operational scenarios reflecting different operations of the dams, are also assessed. The EIS evaluates the impacts of these scenarios relative to socioeconomics, air resources, water resources, ecological resources, cultural resources, land use, recreation, and visual resources.« less

  4. Salt Lake City Area Integrated Projects Electric Power Marketing. Draft environmental impact statement: Volume 2, Sections 1-16

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    The Salt Lake City Area Office of the Western Area Power Administration (Western) markets electricity produced at hydroelectric facilities operated by the Bureau of Reclamation. The facilities are known collectively as the Salt Lake City Area Integrated Projects (SLCA/IP) and include dams equipped for power generation on the Green, Gunnison, Rio Grande, and Colorado rivers and on Deer and Plateau creeks in the states of Wyoming, Utah, Colorado, Arizona, and New Mexico. Of these facilities, only the Glen Canyon Unit, the Flaming Gorge Unit, and the Aspinall Unit (which includes Blue Mesa, Morrow Point, and Crystal dams;) are influenced bymore » Western power scheduling and transmission decisions. The EIS alternatives, called commitment-level alternatives, reflect combinations of capacity and energy that would feasibly and reasonably fulfill Westerns firm power marketing responsibilities, needs, and statutory obligations. The viability of these alternatives relates directly to the combination of generation capability of the SLCA/IP with energy purchases and interchange. The economic and natural resource assessments in this environmental impact statement (EIS) include an analysis of commitment-level alternatives. Impacts of the no-action alternative are also assessed. Supply options, which include combinations of electrical power purchases and hydropower operational scenarios reflecting different operations of the dams, are also assessed. The EIS evaluates the impacts of these scenarios relative to socioeconomics, air resources, water resources, ecological resources, cultural resources, land use, recreation, and visual resources.« less

  5. 76 FR 24048 - Notice of Public Meeting, Southwest Colorado Resource Advisory Council Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-29

    ... Norwood, Colorado; August 26, 2011, in Gunnison, Colorado; and October 28, 2011, in Durango, Colorado. The..., at the San Juan Public Lands Center, 15 Burnett Court, Durango, Colorado 81301. FOR FURTHER...

  6. Lake whitefish and lake herring population structure and niche in ten south-central Ontario lakes

    USGS Publications Warehouse

    Carl, Leon M.; McGuiness, Fiona

    2006-01-01

    This study compares simple fish communities of ten oligotrophic lakes in south-central Ontario. Species densities and population size structure vary significantly among these lake communities depending on fish species present beyond the littoral zone. Lake whitefish are fewer and larger in the presence of lake herring than in their absence. Diet analysis indicates that lake whitefish shift from feeding on both plankton and benthic prey when lake herring are absent to a primarily benthic feeding niche in the presence of lake herring. When benthic round whitefish are present, lake whitefish size and density decline and they move lower in the lake compared to round whitefish. Burbot are also fewer and larger in lakes with lake herring than in lakes without herring. Burbot, in turn, appear to influence the population structure of benthic coregonine species. Lower densities of benthic lake whitefish and round whitefish are found in lakes containing large benthic burbot than in lakes with either small burbot or where burbot are absent. Predation on the pelagic larvae of burbot and lake whitefish by planktivorous lake herring alters the size and age structure of these populations. As life history theory predicts, those species with poor larval survival appear to adopt a bet-hedging life history strategy of long-lived individuals as a reproductive reserve.

  7. On Evaluating circulation and temperature stratification under changing water levels in Lake Mead with a 3D hydrodynamic model

    NASA Astrophysics Data System (ADS)

    Li, Y.; Acharya, K.; Chen, D.; Stone, M.; Yu, Z.; Young, M.; Zhu, J.; Shafer, D. S.; Warwick, J. J.

    2009-12-01

    Sustained drought in the western United States since 2000 has led to a significant drop (about 35 meters) in the water level of Lake Mead, the largest reservoir by volume in United States. The drought combined with rapid urban development in southern Nevada and emergence of invasive species has threatened the water quality and ecological processes in Lake Mead. A three-dimensional hydrodynamic model, Environmental Fluid Dynamics Code (EFDC), was applied to investigate lake circulation and temperature stratification in parts of Lake Mead (Las Vegas Bay and Boulder Basin) under changing water levels. Besides the inflow from Las Vegas Wash and the Colorado River, the model considered atmospheric changes as well as the boundary conditions restricted by the operation of Hoover Dam. The model was calibrated and verified by using observed data including water level, velocity, and temperature from 2003 and 2005. The model was applied to study the hydrodynamic processes at water level 366.8 m (year 2000) and at water level 338.2 m (year 2008). The high-stage simulation described the pre-drought lake hydrodynamic processes while the low-stage simulation highlighted the drawdown impact on such processes. The results showed that both inflow and wind-driven mixing process played major roles in the thermal stratification and lake circulation in both cases. However, the atmospheric boundary played a more important role than inflow temperature on thermal stratification of Lake Mead during water level decline. Further, the thermal stratification regime and flow circulation pattern in shallow lake regions (e.g.., the Boulder Basin area) were most impacted. The temperature of the lake at the high-stage was more sensitive to inflow temperatures than at low-stage. Furthermore, flow velocities decreased with the decreasing water level due to reduction in wind impacts, particularly in shallow areas of the lake. Such changes in temperature and lake current due to present drought have a

  8. Colorado's Prospects for Interstate Commerce in Renewable Power

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hurlbut, D. J.

    2009-12-01

    Colorado has more renewable energy potential than it is ever likely to need for its own in-state electricity consumption. Such abundance may suggest an opportunity for the state to sell renewable power elsewhere, but Colorado faces considerable competition from other western states that may have better resources and easier access to key markets on the West Coast. This report examines factors that will be important to the development of interstate commerce for electricity generated from renewable resources. It examines market fundamentals in a regional context, and then looks at the implications for Colorado.

  9. Method to identify wells that yield water that will be replaced by Colorado River water in Arizona, California, Nevada, and Utah

    USGS Publications Warehouse

    Wilson, Richard P.; Owen-Joyce, Sandra J.

    1994-01-01

    Accounting for the use of Colorado River water is required by the U.S. Supreme Court decree, 1964, Arizona v. California. Water pumped from wells on the flood plain and from certain wells on alluvial slopes outside the flood plain is presumed to be river water and is accounted for as Colorado River water. A method was developed to identify wells outside the f1ood plain of the lower Colorado River that yield water that will be replaced by water from the river. The method provides a uniform criterion of identification for all users pumping water from wells. Wells that have a static water-level elevation equal to or below the accounting surface are presumed to yield water that will be replaced by water from the river. Wells that have a static water-level elevation above the accounting surface are presumed to yield water that will be replaced by water from precipitation and inflow from tributary valleys. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The river aquifer consists of permeable, partly saturated sediments and sedimentary rocks that are hydraulically connected to the Colorado River so that water can move between the river and the aquifer in response to withdrawal of water from the aquifer or differences in water-level elevations between the river and the aquifer. The accounting surface represents the elevation and slope of the unconfined static water table in the river aquifer outside the flood plain and reservoirs that would exist if the river were the only source of water to the river aquifer. Maps at a scale of 1:100,000 show the extent and elevation of the accounting surface from the area surrounding Lake Mead to Laguna Dam near Yuma, Arizona.

  10. Public acceptance of wildlife trapping in Colorado

    USGS Publications Warehouse

    Manfredo, M.J.; Pierce, C.L.; Fulton, D.; Pate, J.; Gill, B.R.

    1999-01-01

    In November 1994, the Colorado Division of Wildlife (CDOW) initiated a stakeholder process to develop trapping regulations that would seek to achieve compromise among divergent interests. A telephone survey was conducted to provide stakeholders with information about the Colorado public's acceptance of trapping. A random sample of 900 residents, stratified by geographic region, indicated that the public would vote to ban trapping and that they believed the ban would eliminate a cruel activity and help to preserve endangered wildlife. Most, however, agreed that trapping was acceptable to prevent spread of disease and to protect livestock, but unacceptable on the basis of providing recreation or making money. Beliefs about trapping were found to be rooted in a protection versus use value orientation about wildlife. The regulations subsequently adopted by the CDOW were consistent with survey findings; however, the regulatory process was bypassed by legislative action, giving trapping authority to the Colorado Department of Agriculture. In response, citizen activists succeeded in placing a ballot initiative before voters. In 1996, the ballot initiative passed, banning trapping in Colorado.

  11. High-mountain lakes as a hotspot of dissolved organic matter production in a changing climate

    NASA Astrophysics Data System (ADS)

    Abood, P. H.; Williams, M. W.; McKnight, D. M.; Hood, E. H.

    2004-12-01

    Changes in climate may adversely affect mountain environments before downstream ecosystems are affected. Steep topography, thin soils with limited extent, sparse vegetation, short growing seasons, and climatic extremes (heavy snowfalls, cold temperatures, high winds), all contribute to the sensitivity of high mountain environments to perturbations. Here we evaluate the role of oligatrophic high-elevation lakes as "hot spots" of aquatic production that may respond to changes in temperature, precipitation amount, and pollution deposition faster and more directly than co-located terrestrial ecosystems. Our research was conducted in the Rocky Mountains, USA. Water samples were collected for dissolved organic carbon (DOC), other solutes, and water isotopes over the course of the runoff season along a longitudinal transect of North Boulder Creek in the Colorado Front Range from the continental divide and alpine areas to downstream forested systems. Sources of DOC were evaluated using chemical fractionation with XAD-8 resins and fluorescence spectroscopy. There was net DOC production in the two alpine lakes but not for the forested subalpine lake. Oxygen-18 values showed that water residence times in lakes increased dramatically in late summer compared to snowmelt. Chemical fractionation of DOC showed there was a increase in the non-humic acid content across the summer of 2003 at all elevations, with alpine waters showing greater increases than subalpine waters. The fluorescence properties of DOC and water isotopes suggested that DOC in aquatic systems was primarily derived from terrestrial precursor material during snowmelt. However, fluorescence properties of DOC in high-elevation lakes on the recession limb of the hydrograph suggest DOC derived from algal and microbial biomass in the lakes was a more important source of DOC in late summer and fall. Alpine lakes produced 14 times more DOC on unit area basis compared to the surrounding terrestrial ecosystems. We

  12. Flora of the Fraser Experimental Forest, Colorado

    Treesearch

    Steve J. Popovich; Wayne D. Shepperd; Donald W. Reichert; Michael A. Cone

    1993-01-01

    This report lists 441 vascular plant taxa in 228 genera and 63 families encountered on the 9,300-ha Fraser Experimental Forest in central Colorado. Synonyms appearing in previous publications and other works pertaining to the Fraser Experimental Forest, as well as appropriate Colorado floras and less-technical field guides, are included. Plant communities and habitats...

  13. ECOREGIONS OF COLORADO

    EPA Science Inventory

    The ecoregions of Colorado have been identified, mapped, and described and provide a geographic structure for environmental resources research, assessment, monitoring, and management. This project is part of a larger effort by the U.S. EPA to create a national, hierarchical ecor...

  14. Groundwater quality in the Colorado River basins, California

    USGS Publications Warehouse

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Four groundwater basins along the Colorado River make up one of the study areas being evaluated. The Colorado River study area is approximately 884 square miles (2,290 square kilometers) and includes the Needles, Palo Verde Mesa, Palo Verde Valley, and Yuma groundwater basins (California Department of Water Resources, 2003). The Colorado River study area has an arid climate and is part of the Sonoran Desert. Average annual rainfall is about 3 inches (8 centimeters). Land use in the study area is approximately 47 percent (%) natural (mostly shrubland), 47% agricultural, and 6% urban. The primary crops are pasture and hay. The largest urban area is the city of Blythe (2010 population of 21,000). Groundwater in these basins is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay deposited by the Colorado River or derived from surrounding mountains. The primary aquifers in the Colorado River study area are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in the Colorado River basins are completed to depths between 230 and 460 feet (70 to 140 meters), consist of solid casing from the land surface to a depth of 130 of 390 feet (39 to 119 meters), and are screened or perforated below the solid casing. The main source of recharge to the groundwater systems in the Needles, Palo Verde Mesa, and Palo Verde Valley basins is the Colorado River; in the Yuma basin, the main source of recharge is from

  15. Effect of Georgetown Lake on the water quality of Clear Creek, Georgetown, Colorado, 1997-98

    USGS Publications Warehouse

    Cuffin, Sally M.; Chafin, Daniel T.

    2000-01-01

    Georgetown Lake is a recreational reservoir located in the upper Clear Creek Basin, a designated Superfund site because of extensive metal mining in the past. Metals concentrations in Clear Creek increase as the stream receives runoff from mining-affected areas. In 1997, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, began a study to determine the effect of the reservoir on the transport of metals in Clear Creek. A bathymetric survey determined the capacity of the reservoir to be about 440 acre-feet of water, which remained constant during the study. Average water residence time in the reservoir is about 1?3 days during high flow. During low flow (10 cubic feet per second), average residence is about 22 days without ice cover and about 15 days with a 3-foot-thick ice cover. Sediment samples collected from the bottom of Georgetown Lake contained substantial concentrations of iron (average 25,500 milligrams per kilogram), aluminum (average 12,300 milligrams per kilogram), zinc (2,830 milligrams per kilogram), lead (618 milligrams per kilogram), manganese (548 milligrams per kilogram), and sulfide minerals (average 602 milligrams per kilogram as S). Sediment also contained abundant sulfate-reducing bacteria, indicating anoxic conditions. Algae and diatoms common to cold-water lakes were identified in sediment samples; one genus of algae is known to adapt to low-light conditions such as exist beneath ice cover. Vertical profiles of temperature, specific conductance, pH, and dissolved-oxygen concentrations were measured in the reservoir on July 28, 1997, when inflow to the reservoir was about 170 cubic feet per second and average residence time of water was about 1.3 days, and on February 13, 1998, when the reservoir was covered with about 3 feet of ice, inflow was about 15 cubic feet per second, and average residence time was about 12 days. The measurements on July 28, 1997, showed that the reservoir water was well mixed

  16. Effects of Desert Dust on Nutrient Cycling in the San Juan Mountains, Colorado

    NASA Astrophysics Data System (ADS)

    Neff, J. C.; Farmer, L.; Painter, T. H.; Landry, C.; Reynolds, R.

    2005-12-01

    The San Juan Mountains of southwestern Colorado lie downwind from several major deserts and experience several dust-deposition events each year. These events appear related to storms that erode soils in the deserts of the western US and then deposit atmospheric dust from these soils during or after snowfall during large late winter and spring deposition events. To evaluate the biogeochemical implications of eolian deposition, we collected dust from distinct layers deposited into the seasonal snowpack. We also sampled soils and lake sediments in a high-elevation catchment in the San Juan Mountains. Atmospheric dust was characterized by measurements of chemical composition, Sr isotopic content and analysis of the organic and inorganic constituents of deposited eolian material. The origins of snowpack dust in the San Juans were analyzed using atmospheric tracer transport modeling. These analyses suggest that many dust events originate in southern Utah and northern Arizona, areas that have undergone substantial land use change through the 20th century and that experience severe wind erosion of soils during periodic severe droughts. Analyses of 87Sr/86Sr isotope ratios dust, soils, bedrock, and sediments suggest that eolian dust may compose as much as 90% of the near-surface soil (top 5 cm). In alpine lake sediments, Sr isotopes suggest a relatively recent (20th century) increase in the fraction of sediments derived from dust (relative to bedrock) and a similarly large contribution of dust to surface sediments. Sediment chemistry in two small alpine tarns show changes in Ca, Mg, Al, and Fe concentrations that imply increasing dust (vs. bedrock) contributions to lake sediments over the past 100-200 years. Increasing loading of Ca, Mg and P to alpine basins may have implications for alpine and sub-alpine biogeochemical cycling including water quality and plant nutrient use.

  17. Hydrogeological features conditioning trophic levels of quarry lakes in western Po plain (north-western Italy)

    NASA Astrophysics Data System (ADS)

    De Luca, Domenico Antonio; Castagna, Sara; Lasagna, Manuela

    2013-04-01

    lakes, for the most part, have rather large depths (over 20 m), and moreover, unlike natural lakes, this type of lake is not influenced by sewage inputs that are often a primary cause of eutrophication in natural lakes. It was shown that, in Piedmont, lakes with a larger depth and volume generally had a lower tendency towards eutrophication. References Castendyk D, Eary T (2009). The nature and global distribution of pit lakes. In, Mine Pit Lakes: Characteristics, Predictive Modeling, and Sustainability Castendyk, D.; Eary, T. and Park, B. (eds.) Society for Mining Engineering (SME), Colorado, USA, 1-11pp. Klapper H, Geller W (2001) Water quality management of mining lakes - a new field of applied hydrobiology. Acta Hydrochim Hydrobiol, 29: 363-374 Castro JM, Moore JN (2000) Pit lakes: their characteristics and the potential for their remediation. Environ Geol, 39(11):1254-1260 Castagna S (2008) Studio delle problematiche idrogeologiche nelle attività estrattive sottofalda per materiali granulari. Ph.D. Thesis.

  18. Ground-Water Occurrence and Movement, 2006, and Water-Level Changes in the Detrital, Hualapai, and Sacramento Valley Basins, Mohave County, Arizona

    USGS Publications Warehouse

    Anning, David W.; Truini, Margot; Flynn, Marilyn E.; Remick, William H.

    2007-01-01

    Ground-water levels for water year 2006 and their change over time in Detrital, Hualapai, and Sacramento Valley Basins of northwestern Arizona were investigated to improve the understanding of current and past ground-water conditions in these basins. The potentiometric surface for ground water in the Basin-Fill aquifer of each basin is generally parallel to topography. Consequently, ground-water movement is generally from the mountain front toward the basin center and then along the basin axis toward the Colorado River or Lake Mead. Observed water levels in Detrital, Hualapai, and Sacramento Valley Basins have fluctuated during the period of historic water-level records (1943 through 2006). In Detrital Valley Basin, water levels in monitored areas have either remained the same, or have steadily increased as much as 3.5 feet since the 1980s. Similar steady conditions or water-level rises were observed for much of the northern and central parts of Hualapai Valley Basin. During the period of historic record, steady water-level declines as large as 60 feet were found in wells penetrating the Basin-Fill aquifer in areas near Kingman, northwest of Hackberry, and northeast of Dolan Springs within the Hualapai Valley Basin. Within the Sacramento Valley Basin, during the period of historic record, water-level declines as large as 55 feet were observed in wells penetrating the Basin-Fill aquifer in the Kingman and Golden Valley areas; whereas small, steady rises were observed in Yucca and in the Dutch Flat area.

  19. 77 FR 13627 - Notice of Inventory Completion: History Colorado, Denver, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ...: History Colorado, Denver, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: History... funerary objects may contact History Colorado. Disposition of the human remains and associated funerary... contact History Colorado at the address below by April 6, 2012. ADDRESSES: Sheila Goff, NAGPRA Liaison...

  20. Organic and inorganic nitrogen pools in talus fields and subtalus water, Green Lakes Valley, Colorado front range

    USGS Publications Warehouse

    Williams, M.W.; Davinroy, T.; Brooks, P.D.

    1997-01-01

    Organic and inorganic pools of nitrogen (N) were measured in talus fines or 'soils' and subtalus water during the summer of 1995 in the alpine Green Lakes Valley catchment of the Colorado Front Range. Nineteen talus soil samples were divided into four classes: subtalus dry, subtalus wet, surface vegetated and surface bare. The size of the individual talus soil patches ranged from 0.5 to 12.0 m2 in area, with bulk density ranging from 0-98 to 1-71 kg m-3 and soil texture ranging from sandy gravel in the subsurface talus to a loam in the vegetated surface. All samples contained KCl-extractable NH4+ and NO3-, organic N and carbon (C), and 17 of 19 samples contained microbial biomass. The mean subtalus values for KCl-extractable NH4-, of 3.2 mg N kg-1, and NO3-, of 1.0 mg N kg-1, were comparable with developed alpine soils on Niwot Ridge. Average microbial biomass in subtalus soils of 5.4 mg N kg-1 and total N of 1000 mg N kg-1 were about an order of magnitude lower than alpine tundra soils, reflecting the reduced amount of vegetation in talus areas. However, these measurements in surface-vegetated patches of talus were comparable with the well-developed soils on Niwot Ridge. These measurements in talus of microbial biomass, total N and KCl-extractable NH4+ and NO3-, show that there is sufficient biotically conditioned 'soil' within talus fields to influence the solute content of interstitial waters. Mean NO3- concentrations of 20 ??eq 1-1 from 29 samples of subtalus water were significantly higher than the 6-7 ??eq 1-1 in snow, while NH4+ concentrations in subtalus water of 0??7 ??eq 1-1 was significantly lower than in snow at 5??2 ??eq 1-1 (p = 0??001). Nitrate concentrations in subtalus water were significantly (p < 0??0001) correlated with concentrations of geochemica??l weathering products such as Ca2+ (r2 = 0??84) and silica (r2 = 0??49). The correlation of NO3- in subtalus water with geochemical weathering products suggests that NO3- concentrations in subtalus

  1. Beyond Colorado's Front Range - A new look at Laramide basin subsidence, sedimentation, and deformation in north-central Colorado

    USGS Publications Warehouse

    Cole, James C.; Trexler, James H.; Cashman, Patricia H.; Miller, Ian M.; Shroba, Ralph R.; Cosca, Michael A.; Workman, Jeremiah B.

    2010-01-01

    This field trip highlights recent research into the Laramide uplift, erosion, and sedimentation on the western side of the northern Colorado Front Range. The Laramide history of the North Park?Middle Park basin (designated the Colorado Headwaters Basin in this paper) is distinctly different from that of the Denver basin on the eastern flank of the range. The Denver basin stratigraphy records the transition from Late Cretaceous marine shale to recessional shoreline sandstones to continental, fluvial, marsh, and coal mires environments, followed by orogenic sediments that span the K-T boundary. Upper Cretaceous and Paleogene strata in the Denver basin consist of two mega-fan complexes that are separated by a 9 million-year interval of erosion/non-deposition between about 63 and 54 Ma. In contrast, the marine shale unit on the western flank of the Front Range was deeply eroded over most of the area of the Colorado Headwaters Basin (approximately one km removed) prior to any orogenic sediment accumulation. New 40Ar-39Ar ages indicate the oldest sediments on the western flank of the Front Range were as young as about 61 Ma. They comprise the Windy Gap Volcanic Member of the Middle Park Formation, which consists of coarse, immature volcanic conglomerates derived from nearby alkalic-mafic volcanic edifices that were forming at about 65?61 Ma. Clasts of Proterozoic granite, pegmatite, and gneiss (eroded from the uplifted core of the Front Range) seem to arrive in the Colorado Headwaters Basin at different times in different places, but they become dominant in arkosic sandstones and conglomerates about one km above the base of the Colorado Headwaters Basin section. Paleocurrent trends suggest the southern end of the Colorado Headwaters Basin was structurally closed because all fluvial deposits show a northward component of transport. Lacustrine depositional environments are indicated by various sedimentological features in several sections within the >3 km of sediment

  2. 77 FR 11573 - Notice of Inventory Completion: History Colorado, Denver, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ...: History Colorado, Denver, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: History... contact History Colorado. Disposition of the human remains to the Indian tribes stated below may occur if... a cultural affiliation with the human remains should contact History Colorado at the address below...

  3. 77 FR 13629 - Notice of Inventory Completion: History Colorado, Denver, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ...: History Colorado, Denver, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: History... human remains may contact History Colorado. Disposition of the human remains to the Indian tribes stated... believes it has a cultural affiliation with the human remains should contact History Colorado at the...

  4. Geochemistry and source waters of rock glacier outflow, Colorado Front Range

    USGS Publications Warehouse

    Williams, M.W.; Knauf, M.; Caine, N.; Liu, F.; Verplanck, P.L.

    2006-01-01

    We characterize the seasonal variation in the geochemical and isotopic content of the outflow of the Green Lake 5 rock glacier (RG5), located in the Green Lakes Valley of the Colorado Front Range, USA. Between June and August, the geochemical content of rock glacier outflow does not appear to differ substantially from that of other surface waters in the Green Lakes Valley. Thus, for this alpine ecosystem at this time of year there does not appear to be large differences in water quality among rock glacier outflow, glacier and blockslope discharge, and discharge from small alpine catchments. However, in September concentrations of Mg2+ in the outflow of the rock glacier increased to more than 900 ??eq L-1 compared to values of less than 40 ??eq L-1 at all the other sites, concentrations of Ca2+ were greater than 4,000 ??eq L-1 compared to maximum values of less than 200 ??eq L-1 at all other sites, and concentrations of SO42- reached 7,000 ??eq L-1, compared to maximum concentrations below 120 ??eq L-1 at the other sites. Inverse geochemical modelling suggests that dissolution of pyrite, epidote, chlorite and minor calcite as well as the precipitation of silica and goethite best explain these elevated concentrations of solutes in the outflow of the rock glacier. Three component hydrograph separation using end-member mixing analysis shows that melted snow comprised an average of 30% of RG5 outflow, soil water 32%, and base flow 38%. Snow was the dominant source water in June, soil water was the dominant water source in July, and base flow was the dominant source in September. Enrichment of ?? 18O from - 10??? in the outflow of the rock glacier compared to -20??? in snow and enrichment of deuterium excess from +17.5??? in rock glacier outflow compared to +11??? in snow, suggests that melt of internal ice that had undergone multiple melt/freeze episodes was the dominant source of base flow. Copyright ?? 2005 John Wiley & Sons, Ltd.

  5. Experimental Floods in a Time of Drought: The 2014 Pulse Flow in the Lower Colorado River, Arizona, USA, and Mexico

    NASA Astrophysics Data System (ADS)

    Kennedy, J.; Ramirez-Hernandez, J.; Ramirez, J.

    2015-12-01

    In March and April, 2014, an unprecedented experimental "pulse flow" with a total volume of over 100 million cubic meters (81,000 acre-feet) of water was released from Morelos Dam into the normally dry lower Colorado River below Yuma, Arizona, for the primary purpose of restoring native vegetation and habitat. Significant infiltration and attenuation of the flood peak occurred within the limitrophe reach that forms the US-Mexico border, with total volume reduced to 57 million cubic meters at the southerly international boundary at San Luis Rio Colorado, Sonora, Mexico (32 kilometers downstream). Groundwater levels in piezometers adjacent to the stream channel rose as much as 10 meters, and surface water/groundwater connection was established throughout the reach, despite depths-to-water greater than 15 meters prior to the pulse flow. Based on groundwater levels, a groundwater mound remained in the vicinity of the stream channel for several months but had largely dissipated into the regional groundwater system by fall 2014. Ultimately, a large amount of water was moved from storage in an upstream reservoir (Lake Mead), where it is potentially available to many users but where evaporation losses can be high, to the regional aquifer in the Yuma-Mexicali area, where the water could be available to local users but cannot be precisely quantified as it moves through the groundwater system. During a time of drought, tradeoffs between local vs. upstream storage, and reservoir vs. subsurface storage, will likely be increasingly important considerations in planning future experimental floods on the Colorado River.

  6. OCCUPATIONS IN COLORADO. PART I, OUTLOOK BY INDUSTRIES.

    ERIC Educational Resources Information Center

    1966

    CURRENT AND PROJECTED EMPLOYMENT STATISTICS ARE GIVEN FOR THE STATE AND FOR THE DENVER STANDARD METROPOLITAN STATISTICAL AREA WHICH INCLUDES ADAMS, ARAPAHOE, BOULDER, DENVER, AND JEFFERSON COUNTIES. DATA WERE OBTAINED FROM THE COLORADO DEPARTMENT OF EMPLOYMENT, DENVER RESEARCH INSTITUTE, U.S. CENSUS, UNIVERSITY OF COLORADO, MOUNTAIN STATES…

  7. 75 FR 6060 - Notice of Public Meeting, Southwest Colorado Resource Advisory Council Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-05

    ... Meeting, Southwest Colorado Resource Advisory Council Meeting AGENCY: Bureau of Land Management. ACTION... Land Management (BLM) Southwest Colorado Resource Advisory Council (RAC) will meet in March 2010. DATES: A Southwest Colorado RAC meeting will be held March 5, 2010. ADDRESSES: The Southwest Colorado RAC...

  8. Surface Hydrological Processes of Rock Glaciated Basins in the San Juan Mountains, Colorado

    NASA Astrophysics Data System (ADS)

    Mateo, E. I.

    2017-12-01

    Glaciers in the western United States have been examined in terms of their summer meltwater contributions to regional hydrological systems. In the San Juan Mountains of Colorado where glaciers do not and cannot exist due to a rising zero-degree isotherm, rock glaciers take the place of valley glaciers during the summer runoff period. Most of the rock glaciers in Colorado are located on a northerly slope aspect, however, there are multiple in the southwest region of the state that occur on different aspects. This study asked how slope aspect and rising air temperatures influenced the hydrological processes of streams below rock glaciers in the San Juan Mountains during the 2016 summer season. This project focused on three basins, Yankee Boy basin, Blue Lakes basin, and Mill Creek basin, which are adjacent to each other and share a common peak, Gilpin Peak. Findings of this one-season study showed that air temperature significantly influenced stream discharge below each rock glacier. Discharge and air temperature patterns indicate a possible air temperature threshold during late summer when rock glacier melt increased at a greater rate. The results also suggest that slope aspect of rock glacier basins influences stream discharge, but temperature and precipitation are likely larger components of the melt regimes. The continuation of data collection during the 2017 summer season has allowed for more detailed analysis of the relationship between air temperature and rock glacier melt. This continual expansion of the original dataset is crucial for understanding the hydrological processes of surface runoff below rock glaciers.

  9. Salinity Trends in the Upper Colorado River Basin Upstream From the Grand Valley Salinity Control Unit, Colorado, 1986-2003

    USGS Publications Warehouse

    Leib, Kenneth J.; Bauch, Nancy J.

    2008-01-01

    In 1974, the Colorado River Basin Salinity Control Act was passed into law. This law was enacted to address concerns regarding the salinity content of the Colorado River. The law authorized various construction projects in selected areas or 'units' of the Colorado River Basin intended to reduce the salinity load in the Colorado River. One such area was the Grand Valley Salinity Control Unit in western Colorado. The U. S. Geological Survey has done extensive studies and research in the Grand Valley Salinity Control Unit that provide information to aid the U.S. Bureau of Reclamation and the Natural Resources Conservation Service in determining where salinity-control work may provide the best results, and to what extent salinity-control work was effective in reducing salinity concentrations and loads in the Colorado River. Previous studies have indicated that salinity concentrations and loads have been decreasing downstream from the Grand Valley Salinity Control Unit, and that the decreases are likely the result of salinity control work in these areas. Several of these reports; however, also document decreasing salinity loads upstream from the Grand Valley Salinity Control Unit. This finding was important because only a small amount of salinity-control work was being done in areas upstream from the Grand Valley Salinity Control Unit at the time the findings were reported (late 1990?s). As a result of those previous findings, the U.S. Bureau of Reclamation entered into a cooperative agreement with the U.S. Geological Survey to investigate salinity trends in selected areas bracketing the Grand Valley Salinity Control Unit and regions upstream from the Grand Valley Salinity Control Unit. The results of the study indicate that salinity loads were decreasing upstream from the Grand Valley Salinity Control Unit from 1986 through 2003, but the rates of decrease have slowed during the last 10 years. The average rate of decrease in salinity load upstream from the Grand Valley

  10. 78 FR 12348 - Notice of Filing of Plats of Survey; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Filing of Plats of Survey; Colorado. SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  11. 78 FR 58343 - Notice of Filing of Plats of Survey; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Filing of Plats of Survey; Colorado SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  12. 77 FR 66630 - Notice of Filing of Plats of Survey; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-06

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado AGENCY: Bureau of Land Management, Interior. ACTION: Notice of filing of plats of survey; Colorado. SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  13. 78 FR 12349 - Notice of Filing of Plats of Survey; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Filing of Plats of Survey; Colorado. SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  14. 77 FR 58862 - Notice of Filing of Plats of Survey; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-24

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Filing of Plats of Survey; Colorado SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  15. 78 FR 74160 - Notice of Filing of Plats of Survey; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-10

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado AGENCY: Bureau of Land Management, Interior. ACTION: Notice of filing of plats of survey; Colorado. SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  16. 78 FR 32439 - Notice of Filing of Plats of Survey; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-30

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Filing of Plats of Survey; Colorado SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  17. 78 FR 20943 - Notice of Filing of Plats of Survey; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-08

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Filing of Plats of Survey; Colorado SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  18. 78 FR 42799 - Notice of Filing of Plats of Survey; Colorado.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-17

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCO956000 L14200000.BJ0000] Notice of Filing of Plats of Survey; Colorado. AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Filing of Plats of Survey; Colorado SUMMARY: The Bureau of Land Management (BLM) Colorado State Office is...

  19. Sources and distribution of organic compounds using passive samplers in Lake Mead National Recreation Area, Nevada and Arizona, and their implications for potential effects on aquatic biota.

    USGS Publications Warehouse

    Rosen, Michael R.; Alvarez, David A.; Goodbred, Steven L.; Leiker, Thomas J.; Patino, Reynaldo

    2009-01-01

    compounds (SOCs) at pg L-1 concentrations. Semi-permeable membrane devices and POCIS were deployed in Lake Mead, at two sites in Las Vegas Wash, at four sites across Lake Mead, and in the Colorado River downstream from Hoover Dam. Concentrations of hydrophobic SOCs were highest in Las Vegas Wash downstream from waste water and urban inputs and at 8 m depth in Las Vegas Bay (LVB) where Las Vegas Wash enters Lake Mead. Th e distribution of hydrophobic SOCs showed a lateral distribution across 10 km of Lake Mead from LVB to Boulder Basin. To assess possible vertical gradients of SOCs, SPMDs were deployed at 4-m intervals in 18 m of water in LVB. Fragrances and legacy SOCs were found at the greatest concentrations at the deepest depth. Th e vertical gradient of SOCs indicated that contaminants were generally confi ned to within 6 m of the lake bottom during the deployment interval. The high SOC concentrations, warmer water temperatures, and higher total dissolved solids concentrations at depth are indicative of a plume of Las Vegas Wash water moving along the lake bottom. Th e lateral and vertical distribution of SOCs is discussed in the context of other studies that have shown impaired health of fi sh exposed to SOCs.

  20. 76 FR 81962 - Notice of Public Meeting, Southwest Colorado Resource Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ... Ridgeway, Colorado; April 27, 2012, in Hotchkiss, Colorado; and October 26, 2012, in Dolores, Colorado... Center at 27501 Highway 184, Dolores, CO, 81323.The meetings will begin at 9 a.m. and adjourn at...

  1. 2016 Lake Michigan Lake Trout Working Group Report

    USGS Publications Warehouse

    Madenjian, Charles P.; Breidert, Brian; Boyarski, David; Bronte, Charles R.; Dickinson, Ben; Donner, Kevin; Ebener, Mark P.; Gordon, Roger; Hanson, Dale; Holey, Mark; Janssen, John; Jonas, Jory; Kornis, Matthew; Olsen, Erik; Robillard, Steve; Treska, Ted; Weldon, Barry; Wright, Greg D.

    2017-01-01

    This report provides a review on the progression of lake trout rehabilitation towards meeting the Salmonine Fish Community Objectives (FCOs) for Lake Michigan (Eshenroder et. al. 1995) and the interim goal and evaluation objectives articulated in A Fisheries Management Implementation Strategy for the Rehabilitation of Lake Trout in Lake Michigan (Dexter et al. 2011); we also include data describing lake trout stocking and mortality to portray the present state of progress towards lake trout rehabilitation.

  2. Simultaneous lidar observations of the water vapor and ozone signatures of a stratospheric intrusion during the MOHAVE-2009 campaign

    NASA Astrophysics Data System (ADS)

    Leblanc, T.; McDermid, I. S.; Pérot, K.

    2010-12-01

    Ozone and water vapor signatures of a stratospheric intrusion were simultaneously observed by the Jet Propulsion Laboratory lidars located at Table Mountain Facility, California (TMF, 34.4N, 117.7W) during the Measurements of Humidity in the Atmosphere and Validation Experiments (MOHAVE-2009) campaign in October 2009. These observations are placed in the context of the meridional displacement and folding of the tropopause, and resulting contrast in the properties of the air masses sampled by lidar. The lidar observations are supported by model data, specifically potential vorticity fields advected by the high-resolution transport model MIMOSA, and by 10-day backward isentropic trajectories. The ozone and water vapor anomalies measured by lidar were largely anti-correlated, and consistent with the assumption of a wet and ozone-poor subtropical upper troposphere, and a dry and ozone-rich extra-tropical lowermost stratosphere. However, it is shown that this anti-correlation relation collapsed just after the stratospheric intrusion event of October 20, suggesting mixed air embedded along the subtropical jet stream and sampled by lidar during its displacement south of TMF (tropopause fold). The ozone-PV expected positive correlation relation held strongly throughout the measurement period, including when a lower polar stratospheric filament passed over TMF just after the stratospheric intrusion. The numerous highly-correlated signatures observed during this event demonstrate the strong capability of the water vapor and ozone lidars at TMF, and provide new confidence in the future detection by lidar of long-term variability of water vapor and ozone in the Upper Troposphere-Lower Stratosphere (UTLS).

  3. Contaminants in American alligator eggs from Lake Apopka, Lake Griffin, and Lake Okeechobee, Florida

    USGS Publications Warehouse

    Heinz, Gary H.; Percival, H. Franklin; Jennings, Michael L.

    1991-01-01

    Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), and 16 elements were measured in American alligator (Alligator mississippiensis) eggs collected in 1984 from Lakes Apopka, Griffin, and Okeechobee in central and south Florida. Organochlorine pesticides were highest in eggs from Lake Apopka. None of the elements appeared to be present at harmful concentrations in eggs from any of the lakes. A larger sample of eggs was collected in 1985, but only from Lakes Griffin, a lake where eggs were relatively clean, and Apopka, where eggs were most contaminated. In 1985, hatching success of artificially incubated eggs was lower for Lake Apopka, and several organochlorine pesticides were higher than in eggs from Lake Griffin. However, within Lake Apopka, higher levels of pesticides in chemically analyzed eggs were not associated with reduced hatching success of the remaining eggs in the clutch. Therefore, it did not appear that any of the pesticides we measured were responsible for the reduced hatching success of Lake Apopka eggs.

  4. NPDES Permit for Eastern Colorado Health Care System (VA Hospital) in Colorado

    EPA Pesticide Factsheets

    Under NPDES permit CO-0034991, the U.S. Department of Veterans Affairs (VA) is authorized to discharge from its wastewater treatment facility in Adams County, Colorado, to a storm sewer to Toll Gate Creek, a tributary of Sand Creek.

  5. Colorado River cutthroat trout: a technical conservation assessment

    Treesearch

    Michael K. Young

    2008-01-01

    The Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus) was once distributed throughout the colder waters of the Colorado River basin above the Grand Canyon. About 8 percent of its historical range is occupied by unhybridized or ecologically significant populations. It has been petitioned for listing under the Endangered Species Act...

  6. 43 CFR 431.7 - Administration and management of the Colorado River Dam Fund.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Colorado River Dam Fund. 431.7 Section 431.7 Public Lands: Interior Regulations Relating to Public Lands... management of the Colorado River Dam Fund. Reclamation is responsible for the repayment of the Project and the administration of the Colorado River Dam Fund and the Lower Colorado River Basin Development Fund...

  7. 43 CFR 431.7 - Administration and management of the Colorado River Dam Fund.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Colorado River Dam Fund. 431.7 Section 431.7 Public Lands: Interior Regulations Relating to Public Lands... management of the Colorado River Dam Fund. Reclamation is responsible for the repayment of the Project and the administration of the Colorado River Dam Fund and the Lower Colorado River Basin Development Fund...

  8. 43 CFR 431.7 - Administration and management of the Colorado River Dam Fund.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Colorado River Dam Fund. 431.7 Section 431.7 Public Lands: Interior Regulations Relating to Public Lands... management of the Colorado River Dam Fund. Reclamation is responsible for the repayment of the Project and the administration of the Colorado River Dam Fund and the Lower Colorado River Basin Development Fund...

  9. Estimation of Stream Flow Losses to the Highland Lakes Inflows during the Recent Period of Run-off Non-stationarity

    NASA Astrophysics Data System (ADS)

    Anderson, R.; Rose, B.; Oliver, L.

    2015-12-01

    The Highland Lakes are operated by the Lower Colorado River Authority (LCRA) in Texas to provide water supply to municipal, industrial, agricultural users and environmental flows for the river and Matagorda Bay. The Highland Lakes also provide for hydroelectric generation and recreation. Subject to extended droughts interrupted by intense rainfall, the region has the nickname of Flash Flood Alley. Recently the Lower Colorado River has experienced a seven year historic drought. While precipitation have been 80% of average, runoff into the Highland lakes have been at historic lows. Multiple regression relationships were developed to predict runoff to the LCRA lakes from rainfall and other factors which explain about 2/3 of the variation of observed inflows. This explanation is good considering the inherent error in stream flow measurement and inflow estimation. It is also comparable to the skill of much more complex dynamical models. Review of the residuals from the relationships reveals periods of unfavorable non-stationarity in inflows after accounting for statistically significant climate and seasonality variables. In particular the periods from 1977 to 1987 as well as 2002 to present showed uncharacteristically low runoff as can be seen in the figure below. Through use of dummy variables for the periods of apparent non-stationarity, the effects of climate and non-stationarity can be quantitatively estimated. At a 90% confidence level, the excess losses in run-off from 2002 to 2015 that can be attributed to lower than median rainfall ranges from 101,000 to 137,000 acre-feet. About another 32,200 to 45,300 acre-feet annually of unrealized inflows can be attributed to typical drought processes. Finally, about another 182,000 to 478,000 acre-feet per year of unrealized inflows can be attributed to unexplained factors in this recent period. These losses are in contrast to runoff during the calendar year of 2011 in which low runoff was better described by extreme

  10. Sanctuaries for lake trout in the Great Lakes

    USGS Publications Warehouse

    Stanley, Jon G.; Eshenroder, Randy L.; Hartman, Wilbur L.

    1987-01-01

    Populations of lake trout, severely depleted in Lake Superior and virtually extirpated from the other Great Lakes because of sea lamprey predation and intense fishing, are now maintained by annual plantings of hatchery-reared fish in Lakes Michigan, Huron, and Ontario and parts of Lake Superior. The extensive coastal areas of the Great Lakes and proximity to large populations resulted in fishing pressure on planted lake trout heavy enough to push annual mortality associated with sport and commercial fisheries well above the critical level needed to reestablish self-sustaining stocks. The interagency, international program for rehabilitating lake trout includes controlling sea lamprey abundance, stocking hatchery-reared lake trout, managing the catch, and establishing sanctuaries where harvest is prohibited. Three lake trout sanctuaries have been established in Lake Michigan: the Fox Island Sanctuary of 121, 500 ha, in the Chippewa-Ottawa Treaty fishing zone in the northern region of the lake; the Milwaukee Reef Sanctuary of 160, 000 ha in midlake, in boundary waters of Michigan and Wisconsin; and Julian's Reef Sanctuary of 6, 500 ha, in Illinois waters. In northern Lake Huron, Drummond Island Sanctuary of 55, 000 ha is two thirds in Indian treaty-ceded waters in Michigan and one third in Ontario waters of Canada. A second sanctuary, Six Fathom Bank-Yankee Reef Sanctuary, in central Lake Huron contains 168, 000 ha. Sanctuary status for the Canadian areas remains to be approved by the Provincial government. In Lake Superior, sanctuaries protect the spawning grounds of Gull Island Shoal (70, 000 ha) and Devils Island Shoal (44, 000 ha) in Wisconsin's Apostle Island area. These seven sanctuaries, established by the several States and agreed upon by the States, Indian tribes, the U.S. Department of the Interior, and the Province of Ontario, contribute toward solving an interjurisdictional fishery problem.

  11. Preliminary Geologic Map of the North-Central Part of the Alamosa 30' x 60' Quadrangle, Alamosa, Conejos and Costilla Counties, Colorado

    USGS Publications Warehouse

    Machette, Michael N.; Thompson, Ren A.; Brandt, Theodore R.

    2008-01-01

    This geologic map presents new polygon (geologic map unit contacts) and line (terrace and lacustrine spit/barrier bar) vector data for a map comprised of four 7.5' quadrangles in the north-central part of the Alamosa, Colorado, 30' x 60' quadrangle. The quadrangles include Baldy, Blanca, Blanca SE, and Lasauses. The map database, compiled at 1:50,000 scale from new 1:24,000-scale mapping, provides geologic coverage of an area of current hydrogeologic, tectonic, and stratigraphic interest. The mapped area is located primarily in Costilla County, but contains portions of Alamosa and Conejos Counties, and includes the town of Blanca in its northeastern part. The map area is mainly underlain by surficial geologic materials (fluvial and lacustrine deposits, and eolian sand), but Tertiary volcanic and volcaniclastic rocks crop out in the San Luis Hills, which are in the central and southern parts of the mapped area. The surficial geology of this area has never been mapped at any scale greater than 1:250,000 (broad reconnaissance), so this new map provides important data for ground-water assessments, engineering geology, and the Quaternary geologic history of the San Luis Basin. Newly discovered shoreline deposits are of particular interest (sands and gravels) that are associated with the high-water stand of Lake Alamosa, a Pliocene to middle Pleistocene lake that occupied the San Luis basin prior to its overflow and cutting of a river gorge through the San Luis Hills. After the lake drained, the Rio Grande system included Colorado drainages for the first time since the Miocene (>5.3 Ma). In addition, Servilleta Basalt, which forms the Basaltic Hills on the east margin of the map area, is dated at 3.79+or-0.17 Ma, consistent with its general age range of 3.67-4.84 Ma. This map provides new geologic information for better understanding ground-water flow paths in and adjacent to the Rio Grande system. The map abuts U.S. Geological Survey Open File Report 2005-1392 (a map of

  12. Colorado as seen from STS-58

    NASA Technical Reports Server (NTRS)

    1993-01-01

    An oblique westward view, across the wheat fields and cattle pastures, of eastern Colorado to the Front Range of the Rocky Mountains. Denver is bisected at the center of the right edge of the frame. Pikes Peak and Colorado Springs are left of center, and the Arkansas River Valley with Canyon City and the Royal Gorge are along the left edge of the frame. This view shows the startling contrast between the nearly-flat High Plains and the ancient geological uplift of the Rockies.

  13. Environmental Setting and Implications on Water Quality, Upper Colorado River Basin, Colorado and Utah

    USGS Publications Warehouse

    Apodaca, Lori E.; Driver, Nancy E.; Stephens, Verlin C.; Spahr, Norman E.

    1995-01-01

    The Upper Colorado River Basin in Colorado and Utah is 1 of 60 study units selected for water-quality assessment as part of the U.S. Geological Survey's National Water-Quality Assessment program, which began full implementation in 1991. Understanding the environmental setting of the Upper Colorado River Basin study unit is important in evaluating water-quality issues in the basin. Natural and human factors that affect water quality in the basin are presented, including an overview of the physiography, climatic conditions, general geology and soils, ecoregions, population, land use, water management and use, hydrologic characteristics, and to the extent possible aquatic biology. These factors have substantial implications on water-quality conditions in the basin. For example, high concentrations of dissolved solids and selenium are present in the natural background water conditions of surface and ground water in parts ofthe basin. In addition, mining, urban, and agricultural land and water uses result in the presence of certain constituents in the surface and ground water of the basin that can detrimentally affect water quality. The environmental setting of the study unit provides a framework of the basin characteristics, which is important in the design of integrated studies of surface water, ground water, and biology.

  14. Geologic map of Colorado National Monument and adjacent areas, Mesa County, Colorado

    USGS Publications Warehouse

    Scott, Robert B.; Harding, Anne E.; Hood, William C.; Cole, Rex D.; Livaccari, Richard F.; Johnson, James B.; Shroba, Ralph R.; Dickerson, Robert P.

    2001-01-01

    New 1:24,000-scale geologic mapping in the Colorado National Monument Quadrangle and adjacent areas, in support of the USGS Western Colorado I-70 Corridor Cooperative Geologic Mapping Project, provides new interpretations of and data for the stratigraphy, structure, geologic hazards in the area from the Colorado River in Grand Valley onto the Uncompahgre Plateau. The plateau drops abruptly along northwest-trending structures toward the northeast 800 m to the Redlands area and the Colorado River in Grand Valley. In addition to common alluvial and colluvial deposits, surficial deposits include Holocene and late Pleistocene charcoal-bearing valley-fill deposits, late to middle Pleistocene river-gravel terrace deposits, Holocene to middle Pleistocene younger, intermediate, and old fan-alluvium deposits, late to middle Pleistocene local gravel deposits, Holocene to late Pleistocene rock-fall deposits, Holocene to middle Pleistocene young and old landslide deposits, Holocene to late Pleistocene sheetwash deposits and eolian deposits, and Holocene Cienga-type deposits. Only the lowest part of the Upper Cretaceous Mancos Shale is exposed in the map area near the Colorado River. The Upper and Lower? Cretaceous Dakota Formation and the Lower Cretaceous Burro Canyon Formation form resistant dipslopes in the Grand Valley and a prominent ridge on the plateau. Less resistant strata of the Upper Jurassic Morrison Formation consisting of the Brushy Basin, Salt Wash, and Tidwell Members form slopes on the plateau and low areas below the mountain front of the plateau. The Middle Jurassic Wanakah Formation nomenclature replaces the previously used Summerville Formation. Because an upper part of the Middle Jurassic Entrada Formation is not obviously correlated with strata found elsewhere, it is therefore not formally named; however, the lower rounded cliff former Slickrock Member is clearly present. The Lower Jurassic silica-cemented Kayenta Formation forms the cap rock for the Lower

  15. Tracking Water-Use in Colorado's Energy Exploration and Development

    NASA Astrophysics Data System (ADS)

    Halamka, T. A.; Ge, S.

    2017-12-01

    By the year 2050 Colorado's population is projected to nearly double, posing many important questions about the stresses that Colorado's water resources will experience. Growing in tandem with Colorado's population is the state's energy exploration and development industry. As water demands increase across the state, the energy exploration and development industry must adapt to and prepare for future difficulties surrounding the legal acquisition of water. The goal of this study is to map out the potential sources of water within the state of Colorado that are being purchased, or will be eligible for purchase, for unconventional subsurface energy extraction. The background of this study includes an overview of the intertwined relationship between water, the energy industry, and the Colorado economy. The project also aims to determine the original purpose of legally appropriated water that is used in Colorado's energy exploration and development. Is the water primarily being purchased or leased from the agricultural sector? Is the water mostly surface water or groundwater? In order to answer these questions, we accessed data from numerous water reporting agencies and examined legal methods of acquisition of water for use in the energy industry. Using these data, we assess the future water quantity available to the energy industry. Knowledge and foresight on the origins of the water used by the energy industry will allow for better and strategic planning of water resources and how the industry will respond to statewide water-related stresses.

  16. Beginning Teacher Induction in the State of Colorado

    ERIC Educational Resources Information Center

    Bierbaum, Myra Desha

    2016-01-01

    The purpose of the study was to gain a deeper understanding of teacher induction in the state of Colorado. The guiding question for the study was "What components do Colorado school districts include as part of their beginning teacher induction?" The study examined the implementation of nine teacher induction components: orientation,…

  17. Ancient lakes, Pleistocene climates and river avulsions structure the phylogeography of a large but little-known rock scorpion from the Mojave and Sonoran deserts

    USGS Publications Warehouse

    Graham, Matthew R.; Wood, Dustin A.; Henault, Jonathan A.; Valois, Zachary J.; Cushing, Paula E.

    2017-01-01

    Recent syntheses of phylogeographical data from terrestrial animals in the Mojave and Sonoran deserts have revealed a complex history of geologic and climatic vicariance events. We studied the phylogeography of Smeringurus vachoni to see how vicariance events may have impacted a large, endemic rock scorpion. Additionally, we used the phylogeographical data to examine the validity of two subspecies of S. vachoni that were described using unconventional morphological characters. Phylogenetic, network and SAMOVA analyses indicate that S. vachoni consists of 11 clades mostly endemic to isolated desert mountain ranges. Molecular clock estimates suggest that clades diversified between the Miocene and early Pleistocene. Species distribution models predict a contraction of suitable habitat during the last glacial maximum. Landscape interpolations and Migrate-n analyses highlight areas of gene flow across the Colorado River. Smeringurus vachoni does not comprise two subspecies. Instead, the species represents at least 11 mitochondrial clades that probably diversified by vicariance associated with Pleistocene climate changes and formation of ancient lakes along the Colorado River corridor. Gene flow appears to have occurred from west to east across the Colorado River during periodic river avulsions.

  18. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

    DeSorcie, Timothy J.; Bowen, Charles A.

    2003-01-01

    Six Fathom Bank-Yankee Reef, an offshore reef complex, was an historically important spawning area believed to represent some of the best habitat for the rehabilitation of lake trout Salvelinus namaycush in Lake Huron. Since 1986, lake trout have been stocked on these offshore reefs to reestablish self-sustaining populations. We sampled with beam trawls to determine the abundance of naturally reproduced age-0 lake trout on these offshore reefs during May-July in 1994-1998 and 2000-2002. In total, 123 naturally reproduced lake trout fry were caught at Six Fathom Bank, and 2 naturally reproduced lake trout fry were caught at nearby Yankee Reef. Our findings suggest that this region of Lake Huron contains suitable habitat for lake trout spawning and offers hope that lake trout rehabilitation can be achieved in the main basin of Lake Huron.

  19. Hydrologic and geochemical approaches for determining ground-water flow components

    USGS Publications Warehouse

    Hjalmarson, H.W.; Robertson, F.N.

    1991-01-01

    Lyman Lake is an irrigation-storage reservoir on the Little Colorado River near St. Johns, Arizona. The main sources of water for the lake are streamflow in the Little Colorado River and ground-water inflow from the underlying Coconino aquifer. Two approaches, a hydrologic analysis and a geochemical analysis, were used to compute the quantity of ground-water flow to and from Lyman Lake. Hydrologic data used to calculate a water budget were precipitation on the lake, evaporation from the lake, transpiration from dense vegetation, seepage through the dam, streamflow in and out of the lake, and changes in lake storage. Geochemical data used to calculate the ground-water flow components were major ions, trace elements, and the stable isotopes of hydrogen and oxygen. During the study, the potentiometric level of the Coconino aquifer was above the lake level at the upstream end of the lake and below the lake level at the downstream end. Hydrologic and geochemical data indicate that about 10 percent and 8 percent, respectively, of the water in the lake is ground-water inflow and that about 35 percent of the water in the Little Colorado River 6 miles downgradient from the lake near Salado Springs is ground water. These independent estimates of ground-water flow derived from each approach are in agreement and support a conceptual model of the water budget.

  20. Effect of power plant emission reductions on a nearby wilderness area: a case study in northwestern Colorado

    USGS Publications Warehouse

    Mast, M. Alisa; Ely, Daniel

    2013-01-01

    This study evaluates the effect of emission reductions at two coal-fired power plants in northwestern Colorado on a nearby wilderness area. Control equipment was installed at both plants during 1999–2004 to reduce SO2 and NOx emissions. One challenge was separating the effects of local from regional emissions, which also declined during the study period. The long-term datasets examined confirm that emission reductions had a beneficial effect on air and water quality in the wilderness. Despite a 75 % reduction in SO2 emissions, sulfate aerosols measured in the wilderness decreased by only 20 %. Because the site is relatively close to the power plants (2 to sulfate, particularly under conditions of low relative humidity, might account for this less than one-to-one response. On the clearest days, emissions controls appeared to improve visibility by about 1 deciview, which is a small but perceptible improvement. On the haziest days, however, there was little improvement perhaps reflecting the dominance of regional haze and other components of visibility degradation particularly organic carbon and dust. Sulfate and acidity in atmospheric deposition decreased by 50 % near the southern end of the wilderness of which 60 % was attributed to power plant controls and the remainder to reductions in regional sources. Lake water sulfate responded rapidly to trends in deposition declining at 28 lakes monitored in and near the wilderness. Although no change in the acid–base status was observed, few of the lakes appear to be at risk from chronic or episodic acidification.

  1. Region 8: Colorado Springs Adequate Letter (8/17/2011)

    EPA Pesticide Factsheets

    This March 3, 2011 letter from EPA to Chistopher E. Urbina M.D., MPH, Colorado Department of Public Health and Environment states that EPA has found that the Colorado Springs, CO second 10 year Limited Maintenance Plan (LMP) adequate for transportation

  2. Guia del Proceso del IFSP de Colorado: Conexiones para la Ninez Temprana, Iniciativa Infantil de Colorado Parte C del Acta de Educacion para Individuos con Desabilidades (Colorado Guidelines for the IFSP Process: Early Childhood Connections, Colorado's Infant/Toddler Initiative for Part C of the Individuals with Disabilities Education Act).

    ERIC Educational Resources Information Center

    Miller, Jerri; Petersen, Sandy

    This booklet for Spanish-speaking parents of young children with disabilities describes Colorado's Individualized Family Service Plan (IFSP) process. It explains guidelines, shares family stories and reflections for families and care providers, and the describes the values that drive the IFSP process in Colorado. Information is provided on…

  3. Colorado as seen from STS-58

    NASA Image and Video Library

    1993-10-30

    STS058-89-013 (18 Oct-1 Nov 1993) --- An oblique westward view, across the wheat fields and cattle pastures, of eastern Colorado to the Front Range of the Rocky Mountains. Denver is bisected at the center of the right edge of the frame. Pikes Peak and Colorado Springs are left of center, and the Arkansas River Valley with Canyon City and the Royal Gorge are along the left edge of the frame. This view shows the startling contrast between the nearly-flat High Plains and the ancient geological uplift of the Rockies.

  4. Understanding uncertainties in future Colorado River streamflow

    USGS Publications Warehouse

    Julie A. Vano,; Bradley Udall,; Cayan, Daniel; Jonathan T Overpeck,; Brekke, Levi D.; Das, Tapash; Hartmann, Holly C.; Hidalgo, Hugo G.; Hoerling, Martin P; McCabe, Gregory J.; Morino, Kiyomi; Webb, Robert S.; Werner, Kevin; Lettenmaier, Dennis P.

    2014-01-01

    The Colorado River is the primary water source for more than 30 million people in the United States and Mexico. Recent studies that project streamf low changes in the Colorado River all project annual declines, but the magnitude of the projected decreases range from less than 10% to 45% by the mid-twenty-first century. To understand these differences, we address the questions the management community has raised: Why is there such a wide range of projections of impacts of future climate change on Colorado River streamflow, and how should this uncertainty be interpreted? We identify four major sources of disparities among studies that arise from both methodological and model differences. In order of importance, these are differences in 1) the global climate models (GCMs) and emission scenarios used; 2) the ability of land surface and atmospheric models to simulate properly the high-elevation runoff source areas; 3) the sensitivities of land surface hydrology models to precipitation and temperature changes; and 4) the methods used to statistically downscale GCM scenarios. In accounting for these differences, there is substantial evidence across studies that future Colorado River streamflow will be reduced under the current trajectories of anthropogenic greenhouse gas emissions because of a combination of strong temperature-induced runoff curtailment and reduced annual precipitation. Reconstructions of preinstrumental streamflows provide additional insights; the greatest risk to Colorado River streamf lows is a multidecadal drought, like that observed in paleoreconstructions, exacerbated by a steady reduction in flows due to climate change. This could result in decades of sustained streamflows much lower than have been observed in the ~100 years of instrumental record.

  5. Lake Nasser and Toshka Lakes, Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Lake Nasser (center) and the Toshka Lakes (center left) glow emerald green and black in this MODIS true-color image acquired March 8, 2002. Located on and near the border of Egypt and Norther Sudan, these lakes are an oasis of water in between the Nubian (lower right) and Libyan Deserts (upper left). Also visible are the Red Sea (in the upper right) and the Nile River (running north from Lake Nasser). Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  6. Peak-flow frequency and extreme flood potential for streams in the vicinity of the Highland Lakes, central Texas

    USGS Publications Warehouse

    Asquith, William H.; Slade, R.M.; Lanning-Rush, Jennifer

    1996-01-01

    The Highland Lakes on the Colorado River are in an area periodically threatened by large storms and floods. Many storms exceeding 10 inches (in.) in depth have been documented in the area, including some with depths approaching 40 in. These storms typically produce large peak discharges that often threaten lives and property. The storms sometimes occur with little warning. Steep stream slopes and thin soils characteristic of the area often cause large peak discharges and rapid movement of floods through watersheds. A procedure to predict the discharge associated with large floods is needed for the area so that appropriate peak discharges can be used in the design of flood plains, bridges, and other structures.The U.S. Geological Survey (USGS), in cooperation with the Lower Colorado River Authority (LCRA), studied flood peaks for streams in the vicinity of the Highland Lakes of central Texas. The Highland Lakes are a series of reservoirs constructed on the Colorado River. The chain of lakes (and year each was completed) comprises Lake Buchanan (1937), Inks Lake (1938), Lake Lyndon B. Johnson (1950), Lake Marble Falls (1951), Lake Travis (1942), and lake Austin (1890). The study area (fig. 1), which includes all or parts of 21 counties in the vicinity of the Highland Lakes, was selected because most streams in the area have flood characteristics similar to streams entering the Highland Lakes. The entire study area is in a region subject to large storms.The purpose of this report is to present (1) peak-flow frequency data for stations and equations to estimate peak-flow frequency for large streams with natural drainage basins in the vicinity of the Highland Lakes, and (2) a technique to estimate the extreme flood peak discharges for the large streams in the vicinity of the Highland Lakes. Peak-flow frequency in this report refers to the peak discharges for recurrence intervals of 2,5, 10,25,50, and 100 years. A large stream is defined as having a contributing drainage

  7. Extensive Green Roof Research Program at Colorado State University

    EPA Science Inventory

    In the high elevation, semi-arid climate of Colorado, green roofs have not been scientifically tested. This research examined alternative plant species, media blends, and plant interactions on an existing modular extensive green roof in Denver, Colorado. Six plant species were ev...

  8. Birds and mammals of Manitou Experimental Forest, Colorado

    Treesearch

    Meredith J. Morris; Vincent H. Reld; Richard E. Pillmore; Mary C. Hammer

    1977-01-01

    Seasonal occurrence, relative abundance, and habitat preference are listed for 90 bird and 41 mammal species that can be found at Manitou Experimental Forest. An annotated list is given also for an additional 70 casual or accidental bird species. Manitou Experimental Forest is located near Colorado Springs in the montane zone of the Colorado Front Range.

  9. School-Finance Reform: Inspiration and Progress in Colorado

    ERIC Educational Resources Information Center

    Herman, Juliana

    2013-01-01

    This report takes a look at Colorado's redesigned school-funding system whose fate was decided by Coloradan voters in Fall 2013. Voters were asked to approve a $1.1 billion tax increase to finance Colorado's schools, an approval required for the funding reforms to kick in. The proposed system represented a significant step forward in the push for…

  10. Selenium stable isotope investigation into selenium biogeochemical cycling in a lacustrine environment: Sweitzer Lake, Colorado.

    PubMed

    Clark, Scott K; Johnson, Thomas M

    2010-01-01

    We present a comprehensive set of Se concentration and isotope ratio data collected over a 3-yr period from dissolved, sediment-hosted, and organically bound Se in a Se-contaminated lake and littoral wetland. Median isotope ratios of these various pools of Se spanned a narrow isotopic range (delta80/76Se(SRM-3149)) = 1.14-2.40 per thousand). Selenium (VI) reduction in the sediments is an important process in this system, but its isotopic impact is muted by the lack of direct contact between surface waters and reduction sites within sediments. This indicates that using Se isotope data as an indicator of microbial or abiotic Se oxyanion reduction is not effective in this or other similar systems. Isotopic data suggest that most Se(IV) in the lake originates from oxidation of organically bound Se rather than directly through Se(VI) reduction. Mobilization of Se(VI) from bedrock involves only a slight isotopic shift. Temporally constant isotopic differences observed in Se(VI) from two catchment areas suggest the potential for tracing Se(VI) from different source areas. Phytoplankton isotope ratios are close to those of the water, with a small depletion in heavy isotopes (0.56 per thousand). Fish tissues nearly match the phytoplankton, being only slightly depleted in the heavier isotopes. This suggests the potential for Se isotopes as migration indicators. Volatile, presumably methylated Se was isotopically very close to median values for phytoplankton and macrophytes, indicating a lack of isotopic fractionation during methylation.

  11. Quantifying Changes in Accessible Water in the Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Castle, S.; Thomas, B.; Reager, J. T.; Swenson, S. C.; Famiglietti, J. S.

    2013-12-01

    The Colorado River Basin (CRB) in the western United States is heavily managed yet remains one of the most over-allocated rivers in the world providing water across seven US states and Mexico. Future water management strategies in the CRB have employed land surface models to forecast discharges; such approaches have focused on discharge estimates to meet allocation requirements yet ignore groundwater abstractions to meet water demands. In this analysis, we illustrate the impact of changes in accessible water, which we define as the conjunctive use of both surface water reservoir storage and groundwater storage, using remote sensing observations to explore sustainable water management strategies in the CRB. We employ high resolution Landsat Thematic Mapper satellite data to detect changes in reservoir storage in the two largest reservoirs within the CRB, Lakes Mead and Powell, and the Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage anomalies to isolate changes in basin-wide groundwater storage in the Upper and Lower CRB from October 2003 to December 2012. Our approach quantifies reservoir and groundwater storage within the CRB using remote sensing to provide new information to water managers to sustainably and conjunctively manage accessible water.

  12. Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

    USGS Publications Warehouse

    Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

    2013-01-01

    Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

  13. Intertonguing of the Lower Part of the Uinta Formation with the Upper Part of the Green River Formation in the Piceance Creek Basin During the Late Stages of Lake Uinta

    USGS Publications Warehouse

    Donnell, John R.

    2009-01-01

    During most of middle Eocene time, a 1,500-mi2 area between the Colorado and White Rivers in northwestern Colorado was occupied by the Piceance lobe of Lake Uinta. This initially freshwater lake became increasingly saline throughout its history. Sediments accumulating in the lake produced mostly clay shale, limestone, and dolomite containing varying concentrations of organic matter. At the time of the maximum extent of the lake, the organic-rich Mahogany bed of the Green River Formation was deposited throughout the area. Shortly after its deposition, stream deposits began infilling the lake from the north through a series of contractions interspersed with minor expansions. This fluctuation of the shoreline resulted in the intertonguing of the stream sediments of the lower part of the overlying Uinta Formation with the lacustrine sediments of the upper part of the Green River over a distance of about 40 mi; construction of regional stratigraphic cross sections show the pattern of intertonguing in considerable detail. The data utilized in this study, which covered parts of Rio Blanco, Garfield, and Mesa counties, was derived from (1) geologic mapping of thirty-four 7 1/2-minute quadrangles and stratigraphic studies by geologists of the U.S. Geological Survey, and (2) shale-oil assay information from numerous cores. As a result of this previous work and the additional effort involved in the compilation here presented, more than a dozen Green River Formation tongues have been named, some formally, others informally. Middle Eocene strata above the Mahogany bed in the northern part of the study area are dominantly coarse clastics of the Uinta Formation. The sedimentary sequence becomes more calcareous and organic-rich to the south where, in a 400-mi2 area, a 250 ft-thick sequence of oil shale above the Mahogany bed contains an average of 16 gallons of oil per ton of shale and is estimated to contain 73 billion barrels of oil.

  14. 75 FR 25877 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-10

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Colorado River Basin Salinity Control Advisory... River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control [[Page 25878

  15. Spatial patterns in PCB concentrations of Lake Michigan lake trout

    USGS Publications Warehouse

    Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.; Brown, Edward H.; Eck, Gary W.; Schmidt, Larry J.; Hesselberg, Robert J.; Chernyak, Sergei M.; Passino-Reader, Dora R.

    1999-01-01

    Most of the PCB body burden in lake trout (Salvelinus namaycush) of the Great Lakes is from their food. PCB concentrations were determined in lake trout from three different locations in Lake Michigan during 1994–1995, and lake trout diets were analyzed at all three locations. The PCB concentrations were also determined in alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), bloater (Coregonus hoyi), slimy sculpin (Cottus cognatus), and deepwater sculpin (Myoxocephalus thompsoni), five species of prey fish eaten by lake trout in Lake Michigan, at three nearshore sites in the lake. Despite the lack of significant differences in the PCB concentrations of alewife, rainbow smelt, bloater, slimy sculpin, and deepwater sculpin from the southeastern nearshore site near Saugatuck (Michigan) compared with the corresponding PCB concentrations from the northwestern nearshore site near Sturgeon Bay (Wisconsin), PCB concentrations in lake trout at Saugatuck were significantly higher than those at Sturgeon Bay. The difference in the lake trout PCB concentrations between Saugatuck and Sturgeon Bay could be explained by diet differences. The diet of lake trout at Saugatuck was more concentrated in PCBs than the diet of Sturgeon Bay lake trout, and therefore lake trout at Saugatuck were more contaminated in PCBs than Sturgeon Bay lake trout. These findings were useful in interpreting the long-term monitoring series for contaminants in lake trout at both Saugatuck and the Wisconsin side of the lake.

  16. Airborne gamma-ray spectrometer and magnetometer survey, Durango A, B, C, and D, Colorado. Volume I. Detail area. Final report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    1983-01-01

    An airborne combined radiometric and magnetic survey was performed for the Department of Energy (DOE) over the Durango A, Durango B, Durango C, and Durango D Detail Areas of southwestern Colorado. The Durango A Detail Area is within the coverage of the Needle Mountains and Silverton 15' map sheets, and the Pole Creek Mountain, Rio Grande Pyramid, Emerald Lake, Granite Peak, Vallecito Reservoir, and Lemon Reservoir 7.5' map sheets of the National Topographic Map Series (NTMS). The Durango B Detail Area is within the coverage of the Silverton 15' map sheet and the Wetterhorn Peak, Uncompahgre Peak, Lake City, Redcloudmore » Peak, Lake San Cristobal, Pole Creek Mountain, and Finger Mesa 7.5' map sheets of the NTMS. The Durango C Detail Area is within the coverage of the Platoro and Wolf Creek Pass 15' map sheets of the NTMS. The Durango D Detail Area is within the coverage of the Granite Lake, Cimarrona Peak, Bear Mountain, and Oakbrush Ridge 7.5' map sheets of the NTMS. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, gridded, and contoured to produce maps of the radiometric variables, uranium, potassium, and thorium; their ratios; and the residual magnetic field. These maps have been analyzed in order to produce a multi-variant analysis contour map based on the radiometric response of the individual geological units. A geochemical analysis has been performed, using the radiometric and magnetic contour maps, the multi-variant analysis map, and factor analysis techniques, to produce a geochemical analysis map for the area.« less

  17. Potential strategies for recovery of lake whitefish and lake herring stocks in eastern Lake Erie

    USGS Publications Warehouse

    Oldenburg, K.; Stapanian, M.A.; Ryan, P.A.; Holm, E.

    2007-01-01

    Lake Erie sustained large populations of ciscoes (Salmonidae: Coregoninae) 120 years ago. By the end of the 19th century, abundance of lake whitefish (Coregonus clupeaformis) had declined drastically. By 1925, the lake herring (a cisco) population (Coregonus artedii) had collapsed, although a limited lake herring fishery persisted in the eastern basin until the 1950s. In the latter part of the 20th century, the composition of the fish community changed as oligotrophication proceeded. Since 1984, a limited recovery of lake whitefish has occurred, however no recovery was evident for lake herring. Current ecological conditions in Lake Erie probably will not inhibit recovery of the coregonine species. Recovery of walleye (Sander vitreus) and efforts to rehabilitate the native lake trout (Salvelinus namaycush) in Lake Erie will probably assist recovery because these piscivores reduce populations of alewife (Alosa psuedoharengus) and rainbow smelt (Osmerus mordax), which inhibit reproductive success of coregonines. Although there are considerable spawning substrates available to coregonine species in eastern Lake Erie, eggs and fry would probably be displaced by storm surge from most shoals. Site selection for stocking or seeding of eggs should consider the reproductive life cycle of the stocked fish and suitable protection from storm events. Two potential sites in the eastern basin have been identified. Recommended management procedures, including commercial fisheries, are suggested to assist in recovery. Stocking in the eastern basin of Lake Erie is recommended for both species, as conditions are adequate and the native spawning population in the eastern basin is low. For lake herring, consideration should be given to match ecophenotypes as much as possible. Egg seeding is recommended. Egg seeding of lake whitefish should be considered initially, with fingerling or yearling stocking suggested if unsuccessful. Spawning stocks of whitefish in the western basin of Lake

  18. 76 FR 70920 - Proposed Amendment of Class E Airspace; Colorado Springs, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-16

    ...-1191; Airspace Docket No. 11-ANM-21] Proposed Amendment of Class E Airspace; Colorado Springs, CO...: This action proposes to amend Class E airspace at City of Colorado Springs Municipal Airport, Colorado Springs, CO. Decommissioning of the Black Forest Tactical Air Navigation System (TACAN) has made this...

  19. Glacial lake inventory and lake outburst potential in Uzbekistan.

    PubMed

    Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

    2017-08-15

    Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m 2 . As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Health hazard evaluation determination report No. 78-128-549, Nixon Power Plant, Colorado Springs, Colorado

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gunter, B.J.

    1978-12-01

    Asbestos (CAS 1332-21-4) concentrations during sanding and buffing operations were measured at the Nixon Power facility (SIC-4911) in Colorado Springs, Colorado on September 29, 1978. The evaluation was requested by the vice president of the Watkin Construction Company on behalf of plumbers engaged in sanding asbestos joints and connections. Breathing zone asbestos concentrations of fibers greater than five microns in length ranged from 0.02 to 0.187 fibers per cubic centimeter. The OSHA asbestos standard of 2 fibers per cubic centimeter was not exceeded, however, the author concludes that a potential asbestos hazard does exist. He recommends that respirators be usedmore » by workers until exhaust ventilation is provided.« less

  1. 75 FR 23288 - Notice of Public Meeting, Southwest Colorado Resource Advisory Council Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-03

    ..., 2010, in Dolores, Colorado; August 13, 2010, in Gunnison, Colorado; and October 8, 2010, in Ridgway... will be held June 4, 2010, at the Anasazi Heritage Center at 27501 Highway 184, Dolores, Colorado 81323...

  2. Progress toward lake trout restoration in Lake Michigan

    USGS Publications Warehouse

    Holey, Mark E.; Rybicki, Ronald W.; Eck, Gary W.; Brown, Edward H.; Marsden, J. Ellen; Lavis, Dennis S.; Toneys, Michael L.; Trudeau, Tom N.; Horrall, Ross M.

    1995-01-01

    Progress toward lake trout restoration in Lake Michigan is described through 1993. Extinction of the native lake trout fishery by sea lamprey predation, augmented by exploitation and habitat destruction, resulted in an extensive stocking program of hatchery-reared lake trout that began in 1965. Sea lamprey abundance was effectively controlled using selective chemical toxicants. The initial stocking produced a measurable wild year class of lake trout by 1976 in Grand Traverse Bay, but failed to continue probably due to excessive exploitation. The overall lack of successful reproduction lakewide by the late 1970s led to the development and implementation in 1985 of a focused inter-agency lakewide restoration plan by a technical committee created through the Lake Committee structure of the Great Lakes Fishery Commission. Strategies implemented in 1985 by the plan included setting a 40% total mortality goal lakewide, creating two large refuges designed to encompass historically the most productive spawning habitat and protect trout stocked over their home range, evaluating several lake trout strains, and setting stocking priorities throughout the lake. Target levels for stocking in the 1985 Plan have never been reached, and are much less than the estimated lakewide recruitment of yearlings by the native lake trout stocks. Since 1985, over 90% of the available lake trout have been stocked over the best spawning habitat, and colonization of the historically productive offshore reefs has occurred. Concentrations of spawning lake trout large enough for successful reproduction, based on observations of successful hatchery and wild stocks, have developed at specific reefs. Continued lack of recruitment at these specific sites suggests that something other than stotk abundance has limited success. Poor survival of lake trout eggs, assumed to be related to contaminant burden, occurred in the late 1970s and early 1980s, but survival has since increased to equal survival in the

  3. Colorado Hispanics: A Report of Selected Social Concerns, 1992.

    ERIC Educational Resources Information Center

    Pappas, Georgia, Ed.; Guajardo, Maria, Ed.

    This publication offers a compilation of 12 reports on selected social concerns pertaining to the Hispanic community in Colorado and provides a comprehensive overview of demographic information and information on health, education, and social welfare issues. The first report looks at Colorado's multicultural population through a demographic…

  4. Colorado Fathers' Resource Guide = Guia de Recursos para los Padres en Colorado.

    ERIC Educational Resources Information Center

    Colorado Foundation for Families and Children, Denver.

    Developed through the Colorado Fatherhood Connection, this guide, in English- and Spanish-language versions, provides suggestions and resources for fathers as well as tips on discipline, communication, and activities fathers can do with their children. Topics addressed in the guide include characteristics of responsible fatherhood, characteristics…

  5. Lake trout rehabilitation in Lake Huron

    USGS Publications Warehouse

    Eshenroder, Randy L.; Payne, N. Robert; Johnson, James E.; Bowen, Charles; Ebener, Mark P.

    1995-01-01

    Efforts to restore lake trout (Salvelinus namaycush) in Lake Huron after their collapse in the 1940s were underway in the early 1970s with completion of the first round of lampricide applications in tributary streams and the stocking of several genotypes. We assess results of rehabilitation and establish a historical basis for comparison by quantifying the catch of spawning lake trout from Michigan waters in 1929-1932. Sixty-eight percent of this catch occurred in northern waters (MH-1) and most of the rest (15%) was from remote reefs in the middle of the main basin. Sea lampreys (Petromyzon marinus) increased in the early 1980s in the main basin and depressed spawning populations of lake trout. This increase was especially severe in northern waters and appeared to be associated with untreated populations in the St. Marys River. Excessive commercial fishing stemming from unresolved treaty rights also contributed to loss of spawning fish in northern Michigan waters. Seneca-strain lake trout did not appear to be attacked by sea lampreys until they reached a size > 532 mm. At sizes > 632 mm, Seneca trout were 40-fold more abundant than the Marquette strain in matched-planting experiments. Natural reproduction past the fry stage has occurred in Thunder Bay and South Bay, but prospects for self-sustaining populations of lake trout in the main basin are poor because sea lampreys are too abundant, only one side of the basin is stocked, and stocking is deferred to allow commercial gillnetting in areas where most of the spawning occurred historically. Backcross lake trout, a lake trout x splake (s. Fontinalis x s. Namaycush) hybrid, did not reproduce in Georgian Bay, but this genotype is being replaced with pure-strain lake trout, whose early performance appears promising.

  6. Updated streamflow reconstructions for the Upper Colorado River Basin

    USGS Publications Warehouse

    Woodhouse, Connie A.; Gray, Stephen T.; Meko, David M.

    2006-01-01

    Updated proxy reconstructions of water year (October–September) streamflow for four key gauges in the Upper Colorado River Basin were generated using an expanded tree ring network and longer calibration records than in previous efforts. Reconstructed gauges include the Green River at Green River, Utah; Colorado near Cisco, Utah; San Juan near Bluff, Utah; and Colorado at Lees Ferry, Arizona. The reconstructions explain 72–81% of the variance in the gauge records, and results are robust across several reconstruction approaches. Time series plots as well as results of cross‐spectral analysis indicate strong spatial coherence in runoff variations across the subbasins. The Lees Ferry reconstruction suggests a higher long‐term mean than previous reconstructions but strongly supports earlier findings that Colorado River allocations were based on one of the wettest periods in the past 5 centuries and that droughts more severe than any 20th to 21st century event occurred in the past.

  7. Updated streamflow reconstructions for the Upper Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Woodhouse, Connie A.; Gray, Stephen T.; Meko, David M.

    2006-05-01

    Updated proxy reconstructions of water year (October-September) streamflow for four key gauges in the Upper Colorado River Basin were generated using an expanded tree ring network and longer calibration records than in previous efforts. Reconstructed gauges include the Green River at Green River, Utah; Colorado near Cisco, Utah; San Juan near Bluff, Utah; and Colorado at Lees Ferry, Arizona. The reconstructions explain 72-81% of the variance in the gauge records, and results are robust across several reconstruction approaches. Time series plots as well as results of cross-spectral analysis indicate strong spatial coherence in runoff variations across the subbasins. The Lees Ferry reconstruction suggests a higher long-term mean than previous reconstructions but strongly supports earlier findings that Colorado River allocations were based on one of the wettest periods in the past 5 centuries and that droughts more severe than any 20th to 21st century event occurred in the past.

  8. Colorado's Singular "No"

    ERIC Educational Resources Information Center

    Wiedeman, Reeves

    2008-01-01

    Supporters of affirmative action may have finally found a way to defeat state ballot measures that would ban such programs: Latch onto an inspirational presidential candidate with piles of cash and an unprecedented voter-turnout machine. Those activists won a narrow victory in Colorado this month, when 50.7 percent of voters made the state the…

  9. View of the Colorado River Canyon showing lower portal road ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of the Colorado River Canyon showing lower portal road in background taken from the rim of Hoover Dam, view south - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  10. Evolution of alkaline lakes - Lake Van case study

    NASA Astrophysics Data System (ADS)

    Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

    2017-04-01

    Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction < 63 µm assuming that it represents only carbonates precipitating in the water column. Microfossil assemblage consists of three different species of ostracods (Candona spp, Loxoconcha sp, Amnicythere spp.), diatoms, gastropods and bivalves. Brakish-water ostracods, Loxoconcha sp and Amnicythere sp occur more often after 530 ka. Additionaly, Loxoconcha sp is a shallow-water species relaying on plants growing in the photic zone as food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic

  11. Applying Dust-on-Snow Research to Colorado Water Management

    NASA Astrophysics Data System (ADS)

    Landry, C. C.; Painter, T. H.; Barrett, A. P.

    2008-12-01

    Snowmelt runoff from seasonal snowpacks in Western mountains provides a high proportion of regional water supplies and represents a critical resource subject to complex management imperatives at all levels of local, state, and federal government. Recent research performed in the San Juan Mountains of Southwest Colorado has revealed that deposition of desert dust from the Colorado Plateau onto Colorado mountain snowpacks is playing a hitherto underestimated forcing role in snowmelt timing and intensity. In spring 2006, embedded dust layers forced a 4-5 week advance in complete snowpack ablation at the Senator Beck Basin Study Area, near Red Mountain Pass, and professional water managers throughout Colorado were surprised by an early and compressed snowmelt runoff. Presentations of our preliminary findings during the summer of 2006 at local water district meetings and at a statewide forum resonated with Colorado water managers and resulted in direct stakeholder engagement in the ongoing research program during the subsequent winter. In spring 2007 the research team issued periodic Dust Alerts describing dust-on-snow conditions extant within the study area, as well as anecdotal reports of conditions elsewhere in the state, and discussed the snowmelt ramifications of those dust conditions in the coming 7-15 days, given mid-range NWS weather forecasts. Another round of presentations at district and state-wide stakeholder meetings in summer 2007 resulted in additional districts and agencies engaging in the program and expanding the dust-on-snow monitoring and Dust Alert analysis efforts in spring 2008 to additional sites distributed throughout the state. The original research project is ongoing and the team is now developing a Colorado Dust-on-Snow Program, CODOS, designed to serve all stakeholders in Colorado snowmelt with increasingly intensive monitoring and analysis of snowmelt forcing by dust, and with ongoing research regarding dust-driven mountain snowmelt

  12. Embryotoxicity of an extract from Great Lakes lake trout to rainbow trout and lake trout

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wright, P.J.; Tillitt, D.E.

    1995-12-31

    Aquatic ecosystems such as the Great Lakes are known to be contaminated with chemicals that are toxic to fish. However, the role of these contaminants in reproductive failures of fishes, such as lake trout recruitment, has remained controvertible. It was the objective to evaluate dioxin-like embryotoxicity of a complex mixture of chemicals and predict their potential to cause the lack of recruitment in Great Lakes lake trout. Graded doses of a complex environmental extract were injected into eggs of both rainbow trout and lake trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988.more » The extract was embryotoxic in rainbow trout, with LD50 values for Arlee strain and Erwin strain of 33 eggEQ and 14 eggEQ respectively. The LOAEL for hemorrhaging, yolk-sac edema, and craniofacial deformities in rainbow trout were 2, 2, and 4 eggEQ, respectively. Subsequent injections of the extract into lake trout eggs were likewise embryotoxic, with an LD50 value of 7 eggEQ. The LOAEL values for the extract in lake trout for hemorrhaging, yolk-sac edema, and craniofacial deformities were 0.1, 1, and 2 eggEQ, respectively. The current levels of contaminants in lake trout eggs are above the threshold for hemorrhaging and yolk-sac edema. The results also support the use of an additive model of toxicity to quantify PCDDs, PCDFs, Non-o-PCBs, and Mono-o-PCBs in relation to early life stage mortality in Lake Michigan lake trout.« less

  13. 76 FR 38684 - Notice of Public Meeting for Proposed Withdrawal Extension; Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ...] Notice of Public Meeting for Proposed Withdrawal Extension; Colorado AGENCY: Bureau of Land Management... 2, 2011, in Pueblo, Colorado. The meeting will begin at 6 p.m. and adjourn at approximately 8 p.m... Sangre De Cristo Arts and Conference Center, 210 N. Santa Fe Ave., Pueblo, Colorado. FOR FURTHER...

  14. Streamflow and sediment-transport data, Colorado River and three tributaries in Grand Canyon, Arizona, 1983 and 1985-86

    USGS Publications Warehouse

    Garrett, W.B.; van de Vanter, E.K.; Graf, J.B.

    1993-01-01

    The U.S. Geological Survey collected streamflow and sediment-transport data at 5 streamflow-gaging stations on the Colorado River between Glen Canyon Dam and Lake Mead as a part of an interagency environmental study. The data were collected for about 6 mo in 1983 and about 4 mo in 1985-86; data also were collected at 3 sites on tributary streams in 1983. The data were used for development of unsteady flow-routing and sediment-transport models, sand-load rating curves, and evaluation of channel changes. For the 1983 sampling period, 1,076 composite cross-section suspended-sediment samples were analyzed; 809 of these samples were collected on the main stem of the Colorado River and 267 samples were from the tributaries. Bed-material samples were obtained at 1,988 verticals; 161 samples of material in transport near the bed (bedload) were collected to define the location of sand, gravel, and bed rock in the channel cross section; and 664 discharge measurements were made. For the 1985-86 sampling period, 765 composite cross-section suspended-sediment samples and 887 individual vertical samples from cross sections were analyzed. Bed-material samples were obtained at 531 verticals, 159 samples of bedload were collected, and 218 discharge measurements were made. All data are presented in tabular form. Some types of data also are presented in graphs to better show trends or variations. (USGS)

  15. View of the Colorado River Canyon form the Nevada side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of the Colorado River Canyon form the Nevada side showing the Nevada rim towers and portions of US 93, view south - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  16. View of Nevada side of Colorado River Canyon showing US ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Nevada side of Colorado River Canyon showing US 93 in foreground, transmission towers and static towers in background, view west - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  17. Hydrogeologic Controls on Lake Level at Mountain Lake, Virginia

    NASA Astrophysics Data System (ADS)

    Roningen, J. M.; Burbey, T. J.

    2011-12-01

    Mountain Lake in Giles County, Virginia has a documented history of severe natural lake-level changes involving groundwater seepage that extend over the past 4200 years. Featured in the 1986 movie Dirty Dancing, the natural lake dried up completely in September 2008 and levels have not yet recovered. A hydrogeologic investigation was undertaken in an effort to determine the factors influencing lake level changes. A daily water balance, dipole-dipole electrical resistivity surveying, well logging and chemical sampling have shed light on: 1) the influence of a fault not previously discussed in literature regarding the lake, 2) the seasonal response to precipitation of a forested first-order drainage system in fractured rock, and 3) the possibility of flow pathways related to karst features. Geologic controls on lake level were investigated using several techniques. Geophysical surveys using dipole-dipole resistivity located possible subsurface flowpaths both to and from the lake. Well logs, lineament analysis, and joint sampling were used to assess structural controls on lake hydrology. Major ions were sampled at wells, springs, streams, and the lake to evaluate possible mixing of different sources of water in the lake. Groundwater levels were monitored for correlation to lake levels, rainfall events, and possible seismic effects. The hydrology of the lake was quantified with a water balance on a daily time step. Results from the water balance indicate steady net drainage and significant recharge when vegetation is dormant, particularly during rain-on-snow melt events. The resistivity survey reveals discrete areas that represent flow pathways from the lake, as well as flowpaths to springs upgradient of the lake located in the vicinity of the fault. The survey also suggests that some flowpaths may originate outside of the topographic watershed of the lake. Chemical evidence indicates karst may underlie the lakebed. Historical data suggest that artificial intervention

  18. Game Birds of Colorado.

    ERIC Educational Resources Information Center

    Colorado State Div. of Wildlife, Denver.

    This booklet is intended to familiarize the reader with game birds typical of Colorado. Discussions in English and Spanish are presented. Discussions cover the management of game birds, individual game bird species, and endangered species of birds related to game birds. (RE)

  19. Sand deposition in the Colorado River in the Grand Canyon from flooding of the Little Colorado River

    USGS Publications Warehouse

    Wiele, S.M.; Graf, J.B.; Smith, J.D.

    1996-01-01

    Methods for computing the volume of sand deposited in the Colorado River in Grand Canyon National Park by floods in major tributaries and for determining redistribution of that sand by main-channel flows are required for successful management of sand-dependent riparian resources. We have derived flow, sediment transport, and bed evolution models based on a gridded topography developed from measured channel topography and used these models to compute deposition in a short reach of the river just downstream from the Little Colorado River, the largest tributary in the park. Model computations of deposition from a Little Colorado River flood in January 1993 were compared to bed changes measured at 15 cross sections. The total difference between changes in cross-sectional area due to deposition computed by the model and the measured changes was 6%. A wide reach with large areas of recirculating flow and large depressions in the main channel accumulated the most sand, whereas a reach with similar planimetric area but a long, narrow shape and relatively small areas of recirculating flow and small depressions in the main channel accumulated only about a seventh as much sand. About 32% of the total deposition was in recirculation zones, 65% was in the main channel, and 3% was deposited along the channel margin away from the recirculation zone. Overall, about 15% of the total input of sand from this Little Colorado River flood was deposited in the first 3 km below the confluence, suggesting that deposition of the flood-derived material extended for only several tens of kilometers downstream from the confluence.

  20. Impacts of Population, Climate Variability and Change on the Management of the Colorado River

    NASA Astrophysics Data System (ADS)

    Udall, B. H.; Pulwarty, R.; Kenney, D.

    2005-12-01

    The Colorado River has been called the lifeline of the West. Draining portions of seven states and nearly 250,000 square miles, this river serves the needs of over 25 million people including all of the Southwest's major cities and several million acres of some of the most productive irrigated agriculture in the United States. Since a 1922 interstate compact first allocated the river, there have been numerous federal laws, Supreme Court decrees, and administrative decisions relating to the use of the system. The result is the most complex legal environment pertaining to water in the world. In addition, billions of dollars have been spent constructing huge reservoirs including Lake Mead and Lake Powell which in total store over four years of supply. Despite the enormous system capacity, new demands resulting from long-term population growth and from the completion of new water delivery projects, and an unprecedented five-year drought from 2000 to 2004 severely stressed both the water supply and the legal framework in the basin. The CU-NOAA Western Water Assessment, one of eight NOAA- OGP funded Regional Integrated Sciences and Assessments, conducts research, and provides decision support resources to water managers in the basin. Specifically, we provide paleoclimatology research and products, legal analysis, seasonal and sub-seasonal forecasting, climate change assessments, and system yield modeling. This presentation will feature a case study of the Western Water Assessment's activities in the basin including our involvement with several key stakeholders.

  1. Lake-level frequency analysis for Devils Lake, North Dakota

    USGS Publications Warehouse

    Wiche, Gregg J.; Vecchia, Aldo V.

    1996-01-01

    Two approaches were used to estimate future lake-level probabilities for Devils Lake. The first approach is based on an annual lake-volume model, and the second approach is based on a statistical water mass-balance model that generates seasonal lake volumes on the basis of seasonal precipitation, evaporation, and inflow. Autoregressive moving average models were used to model the annual mean lake volume and the difference between the annual maximum lake volume and the annual mean lake volume. Residuals from both models were determined to be uncorrelated with zero mean and constant variance. However, a nonlinear relation between the residuals of the two models was included in the final annual lakevolume model.Because of high autocorrelation in the annual lake levels of Devils Lake, the annual lake-volume model was verified using annual lake-level changes. The annual lake-volume model closely reproduced the statistics of the recorded lake-level changes for 1901-93 except for the skewness coefficient. However, the model output is less skewed than the data indicate because of some unrealistically large lake-level declines. The statistical water mass-balance model requires as inputs seasonal precipitation, evaporation, and inflow data for Devils Lake. Analysis of annual precipitation, evaporation, and inflow data for 1950-93 revealed no significant trends or long-range dependence so the input time series were assumed to be stationary and short-range dependent.Normality transformations were used to approximately maintain the marginal probability distributions; and a multivariate, periodic autoregressive model was used to reproduce the correlation structure. Each of the coefficients in the model is significantly different from zero at the 5-percent significance level. Coefficients relating spring inflow from one year to spring and fall inflows from the previous year had the largest effect on the lake-level frequency analysis.Inclusion of parameter uncertainty in the model

  2. Lake-level frequency analysis for Devils Lake, North Dakota

    USGS Publications Warehouse

    Wiche, Gregg J.; Vecchia, Aldo V.

    1995-01-01

    Two approaches were used to estimate future lake-level probabilities for Devils Lake. The first approach is based on an annual lake-volume model, and the second approach is based on a statistical water mass-balance model that generates seasonal lake volumes on the basis of seasonal precipitation, evaporation, and inflow.Autoregressive moving average models were used to model the annual mean lake volume and the difference between the annual maximum lake volume and the annual mean lake volume. Residuals from both models were determined to be uncorrelated with zero mean and constant variance. However, a nonlinear relation between the residuals of the two models was included in the final annual lake-volume model.Because of high autocorrelation in the annual lake levels of Devils Lake, the annual lakevolume model was verified using annual lake-level changes. The annual lake-volume model closely reproduced the statistics of the recorded lake-level changes for 1901-93 except for the skewness coefficient However, the model output is less skewed than the data indicate because of some unrealistically large lake-level declines.The statistical water mass-balance model requires as inputs seasonal precipitation, evaporation, and inflow data for Devils Lake. Analysis of annual precipitation, evaporation, and inflow data for 1950-93 revealed no significant trends or long-range dependence so the input time series were assumed to be stationary and short-range dependent.Normality transformations were used to approximately maintain the marginal probability distributions; and a multivariate, periodic autoregressive model was used to reproduce the correlation structure. Each of the coefficients in the model is significantly different from zero at the 5-percent significance level. Coefficients relating spring inflow from one year to spring and fall inflows from the previous year had the largest effect on the lake-level frequency analysis.Inclusion of parameter uncertainty in the model

  3. Lake trout in northern Lake Huron spawn on submerged drumlins

    USGS Publications Warehouse

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

    2014-01-01

    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

  4. Overview of the Colorado River Canyon from the helicopter pad. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Overview of the Colorado River Canyon from the helicopter pad. View of the Nevada side where new bridge will cross canyon, view northwest - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  5. Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario

    USGS Publications Warehouse

    Adams, W.E.; Kallemeyn, L.W.; Willis, D.W.

    2006-01-01

    Rainy Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake and to relate environmental factors to year-class strength for this population. Gill-netting efforts throughout the study resulted in the capture of 322 lake sturgeon, including 50 recaptures. Lake sturgeon in Rainy Lake was relatively plump and fast growing compared with a 32-population summary. Population samples were dominated by lake sturgeon between 110 and 150 cm total length. Age–structure analysis of the samples indicated few younger (<10 years) lake sturgeon, but the smallest gill net mesh size used for sampling was 102 mm (bar measure) and would not retain small sturgeon. Few lake sturgeon older than age 50 years were captured, and maximum age of sampled fish was 59 years. Few correlations existed between lake sturgeon year-class indices and both annual and monthly climate variables, except that mean June air temperature was positively correlated with year-class strength. Analysis of Rainy Lake water elevation and resulting lake sturgeon year-class strength indices across years yielded consistent but weak negative correlations between late April and early June, when spawning of lake sturgeon occurs. The baseline data collected in this study should allow Rainy Lake biologists to establish more specific research questions in the future.

  6. Colorado Disciplinary Practices, 2008-2010: Disciplinary Actions, Student Behaviors, Race, and Gender

    ERIC Educational Resources Information Center

    Pfleger, Ryan; Wiley, Kathryn

    2012-01-01

    The Colorado legislature has recently taken school discipline policies under review, pursuant to SB 11-133. To inform the discussion in Colorado as well as a national discussion about discipline, this report presents an analysis of the most complete set of Colorado discipline data. It adds to and reinforces existing studies, documenting some…

  7. 78 FR 62657 - Notice of Public Meeting, Southwest Colorado Resource Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... indicated below. DATES: The Southwest Colorado RAC meeting will be held on November 15, 2013, in Dolores, Colorado. ADDRESSES: The Southwest Colorado RAC meeting will be held November 15, 2013, at the Dolores Public Lands Center, 29211 Highway 184, Dolores, CO 81323. The meeting will begin at 9 a.m. and adjourn...

  8. Recreational Cannabis Legalization and Opioid-Related Deaths in Colorado, 2000-2015.

    PubMed

    Livingston, Melvin D; Barnett, Tracey E; Delcher, Chris; Wagenaar, Alexander C

    2017-11-01

    To examine the association between Colorado's legalization of recreational cannabis use and opioid-related deaths. We used an interrupted time-series design (2000-2015) to compare changes in level and slope of monthly opioid-related deaths before and after Colorado stores began selling recreational cannabis. We also describe the percent change in opioid-related deaths by comparing the unadjusted model-smoothed number of deaths at the end of follow-up with the number of deaths just prior to legalization. Colorado's legalization of recreational cannabis sales and use resulted in a 0.7 deaths per month (b = -0.68; 95% confidence interval = -1.34, -0.03) reduction in opioid-related deaths. This reduction represents a reversal of the upward trend in opioid-related deaths in Colorado. Legalization of cannabis in Colorado was associated with short-term reductions in opioid-related deaths. As additional data become available, research should replicate these analyses in other states with legal recreational cannabis.

  9. View of Nevada side of Colorado River Canyon showing US ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Nevada side of Colorado River Canyon showing US 93, Visitor Center parking lot, transmission lines, and static towers in background, view west - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  10. Pleistocene lake level changes in Western Mongolia

    NASA Astrophysics Data System (ADS)

    Borodavko, P. S.

    2009-04-01

    .Petersburg, Nauka, 304 p. 4. Tarasov, P.E., Harrison, S.P., Saarse, L., Pushenko, M.Ya., Andreev, A.A., Aleshinskaya, Z.V., Davydova, N.N., Dorofeyuk, N.I., Efremov, Yu.V., Khomutova, V.I., Sevastyanov, D.V., Tamosaitis, J., Dorofeyuk, N.I., Efremov, Yu.V., Khomutova, V.I., Sevastyanov, D.V., Tamosaitis, J.,Uspenskaya, O.N., Yakushko, O.F. and Tarasova, I.V., 1994. Lake status records from the Former Soviet Union and Mongolia: Data Base Documentation, World Data Center -A for Paleoclimatology NOAA Paleoclimatology Program, Paleoclimatology Publications Series Report No 2, Boulder, Colorado USA, 274 p. 5. Tserensodnom, Zh., 1971. Mongol orny Nuur. Ulaanbaatar, TUAH, 202 p. 6. Vipper, P., Dorofeyuk, N., Liiva, A., Meteltseva, E., and Sokolovskaya, V., 1981. Palaeogeography of the Central Mongolia during the upper Pleistocene and Holocene. Izv. Akad. Nauk ESSR, Ser. Biol., vol. 30, no. 1, pp. 74-82.

  11. 76 FR 43715 - Notice of Inventory Completion: University of Colorado Museum, Boulder, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-21

    ...: University of Colorado Museum, Boulder, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The University of Colorado Museum has completed an inventory of human remains and associated funerary... associated funerary objects may contact the University of Colorado Museum. [[Page 43716

  12. Wood use in Colorado at the turn of the twenty-first century

    Treesearch

    Dennis L. Lynch; Kurt Mackes

    2001-01-01

    This study estimates the kinds, uses, amount, and retail value of wood products consumed annually in Colorado from 1997 to 2000. Colorado uses tremendous amounts of wood products, but it imports most of it from other states and countries despite the abundant forests in Colorado that are capable of providing many types of wood products.

  13. Monitoring and Research of the Colorado River Ecosystem: When Is Enough Enough?

    NASA Astrophysics Data System (ADS)

    Schmidt, J. C.

    2014-12-01

    The Glen Canyon Dam Adaptive Management Program (GCDAMP) is a well-funded ( $10 million/yr.) river rehabilitation program with long-term monitoring and research focused on 400 km of the Colorado River in Glen, Marble, and Grand Canyons downstream from Lake Powell. More than 15 years of substantive science concerning hydrology, hydraulics, sediment transport, geomorphology, aquatic and fish ecology, riparian ecology, and socio-economics has yielded significant insights that guide experimental river management initiatives, such as a new protocol to annually release sediment-triggered controlled floods; administratively called the High Flow Experimental Protocol (HFEP). Implementation of the HFEP requires nearly real-time monitoring of sediment delivery from key sand producing tributaries, transport in and calculation of sand mass balance in segments of the Colorado River, and defined uncertainty of those processes and conditions (see: http://www.gcmrc.gov/). The HFEP aims to rebuild sandbars within the active channel, but many stakeholders remain focused on other aquatic ecosystem, riparian ecosystem, archaeological resources, or cultural values that are linked in complex ways to active channel conditions. Tension exists within the GCDAMP about how funding is allocated for innovative data collection, analysis, and publication strategies that allow implementation of the HFEP, and to also measure derivative resource conditions about which some stakeholders have concern. Monitoring and research initiatives that attempt to incorporate traditional cultural values also have high uncertainty when resource condition is linked with the simple implementation paradigm of the HFEP. Thus, the GCDAMP is faced with the complex challenge of allocating sufficient resources to monitor active channel processes and characteristics, resolve remaining scientific uncertainties, and develop new strategies for incorporating science insights into engineering and policy decisions, while also

  14. Charters, Constitutions and By-Laws of the Indian Tribes of North America; Part III: The Southwest (Apache--Mohave). Occasional Publications in Anthropology Ethnology Series No. 4.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    The Museum of Anthropology of the University of Northern Colorado (formerly known as Colorado State College) has assembled a large number of Indian tribal charters, constitutions, and by-laws to be reproduced as a series of publications. Included in this volume are the amended charter and constitution of the Jicarilla Apache Tribe, Dulce, New…

  15. View of Nevada side of Colorado River Canyon taken from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Nevada side of Colorado River Canyon taken from Lower Portal Road looking up towards area where new bridge will be located, view northwest - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  16. View of Arizona side of Colorado River Canyon taken from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Arizona side of Colorado River Canyon taken from Lower Portal Road looking up towards area where new bridge will be located, view northeast - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  17. Estimated use of water in Colorado, 1985

    USGS Publications Warehouse

    Litke, D.W.; Appel, C.L.

    1989-01-01

    Water-use data was collected for the State of Colorado as part of the U.S. Geological Survey 's National Water-Use Information Program. An estimated 20,800 million gal/day of water were used in Colorado during 1985. 89% came from surface water sources and 11% came from groundwater sources. Public supply systems provided 4% of all water used in Colorado during 1985, but provided 80% of all commercial, domestic, and industrial water used. An estimated 4,840 million gal/day of water were consumed during 1985; return flows amounted to 16,000 million gallons per day. Of all water used, 60% was used for irrigation, 35% for hydroelectric power generation, and the remaining 5% for commercial, domestic, industrial, livestock, mining, and other uses. The most water was used in Montrose (3,260 million gal/day), Mesa (1,950 million gal/day), and Gunnison (1,520 million gal/day) Counties. The predominant water uses in these counties were hydroelectric power and irrigation. (USGS)

  18. Lake Level Variation in Small Lakes: Not a Clear Picture

    NASA Astrophysics Data System (ADS)

    Starratt, S.

    2017-12-01

    Lake level is a useful tool for identifying regional changes in precipitation and evaporation. Due to the volume of water in large lakes, they may only record large-scale changes in water balance, while smaller lakes may record more subtle variations. However, the record of water level in small lakes is affected by a number of factors including elevation, bathymetry, nutrient load, and aquatic macrophyte abundance. The latest Quaternary diatom records from three small lakes with areas of <10 ha (Hobart Lake, OR, 1458 masl; Swamp Lake, CA, 1554 masl; Favre Lake, NV, 2899 masl) and a larger lake (Medicine Lake, CA, 2036 masl, 154 ha) were compared in this study. All the lakes have a deep central basin (>10 m) surrounded by a shallow (1-2 m) shelf. Changes in the abundance of diatoms representing different life habits (benthic, tychoplanktic, planktic) were used to identify lake level variation. Benthic taxa dominate the assemblage when only the central basin is occupied. As the shallow shelf is flooded, the abundance of tychoplanktic taxa increases. Planktic taxa increase with the establishment of stratification. Favre Lake presents the clearest indication of initial lake level rise (7600-5750 cal yr BP) and intermittent flooding of the shelf for the remainder of the record. Stratification appears to become established only in the last few hundred years. Higher nutrient levels in the early part of the Hobart Lake record lead to a nearly monotypic planktic assemblage which is replaced by a tychoplanktic-dominated assemblage as the lake floods the shelf at about 3500 cal yr BP. The last 500 years is dominated by benthic taxa associated with aquatic macrophytes. The consistent presence of planktic taxa in the Swamp Lake record suggests that the lake was stratified during most of its history, although slight variations in the relative abundances of planktic and tychoplanktic groups occur. The Medicine Lake record shows a gradual increase in planktic species between 11

  19. Monitoring riparian-vegetation composition and cover along the Colorado River downstream of Glen Canyon Dam, Arizona

    USGS Publications Warehouse

    Palmquist, Emily C.; Ralston, Barbara E.; Sarr, Daniel A.; Johnson, Taylor C.

    2018-06-05

    Vegetation in the riparian zone (the area immediately adjacent to streams, such as stream banks) along the Colorado River downstream of Glen Canyon Dam, Arizona, supports many ecosystem and societal functions. In both Glen Canyon and Grand Canyon, this ecosystem has changed over time in response to flow alterations, invasive species, and recreational use. Riparian-vegetation cover and composition are likely to continue to change as these pressures persist and new ones emerge. Because this system is a valuable resource that is known to change in response to flow regime and other disturbances, a long-term monitoring protocol has been designed with three primary objectives:Annually measure and summarize the status (composition and cover) of native and non-native vascular-plant species within the riparian zone of the Colorado River between Glen Canyon Dam and Lake Mead.At 5-year intervals, assess change in vegetation composition and cover in the riparian zone, as related to geomorphic setting and dam operations, particularly flow regime.Collect data in a manner that can be used by multiple stakeholders, particularly the basinwide monitoring program overseen by the National Park Service’s Northern Colorado Plateau Network Inventory and Monitoring program.A protocol for the long-term monitoring of riparian vegetation is described in detail and standard operating procedures are included herein for all tasks. Visual estimates of foliar and ground covers are collected in conjunction with environmental measurements to assess correlations of foliar cover with abiotic and flow variables. Sample quadrats are stratified by frequency of inundation, geomorphic feature, and by river segment to account for differences in vegetation type. Photographs of sites are also taken to illustrate qualitative characteristics of the site at the time of sampling. Procedures for field preparation, generating random samples, data collection, data management, collecting and managing unknown

  20. 76 FR 14063 - Notice of Inventory Completion: University of Colorado Museum, Boulder, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-15

    ...: University of Colorado Museum, Boulder, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The University of Colorado Museum has completed an inventory of human remains and associated funerary... contact the University of Colorado Museum. Disposition of the human remains and associated funerary...

  1. 76 FR 43713 - Notice of Inventory Completion: University of Colorado Museum, Boulder, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-21

    ...: University of Colorado Museum, Boulder, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The University of Colorado Museum has completed an inventory of human remains and an associated... human remains and associated funerary object may contact the University of Colorado Museum. Disposition...

  2. 78 FR 53675 - Safety Zone; Lake Erie Heritage Foundation, Battle of Lake Erie Reenactment; Lake Erie, Put-in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ...-AA00 Safety Zone; Lake Erie Heritage Foundation, Battle of Lake Erie Reenactment; Lake Erie, Put-in-Bay... temporary safety zone in the waters of Lake Erie in the vicinity of Put-In-Bay, OH. This safety zone is intended to restrict vessels from a portion of Lake Erie during Battle of Lake Erie Reenactment near Put-In...

  3. Colorado Vocational Act. Twentieth and Twenty-First Annual Reports.

    ERIC Educational Resources Information Center

    Smith, Gregory P.; Lillard, Jerry

    This document combines two annual reports on the Colorado Vocational Act for 1990 and 1991. Both reports contain the following materials: (1) a letter from the president; (2) information and fact sheet; (3) definitions; and statistical data on the following: (4) enrollment and placement trends, 1987-1990; (5) Colorado vocational and other…

  4. Centauri High School Teacher Honored as Colorado Outstanding Biology

    Science.gov Websites

    Teacher Centauri High School Teacher Honored as Colorado Outstanding Biology Teacher For more information contact: e:mail: Public Affairs Golden, Colo., May 2, 1997 -- Tracy Swedlund, biology teacher at Centauri High School in LaJara, was selected as Colorado's 1997 Outstanding Biology Teacher and will be

  5. Latinos in Colorado: A Profile of Culture, Changes, and Challenges. Volume V.

    ERIC Educational Resources Information Center

    Pappas, Georgia, Ed.; Guajardo, Maria, Ed.

    It is projected that the population of Colorado will increase by 25% between 1990 and 2000. The Latino community will experience a slight increase in the proportion of Colorado's population, and will remain the largest ethnic group over the next 30 years. The chapters in this profile describe the Latino population of Colorado. The following essays…

  6. Lake trout spawning habitat in the Six Fathom Bank-Yankee Reef lake trout sanctuary, Lake Huron

    USGS Publications Warehouse

    Edsall, Thomas A.; Brown, Charles L.; Kennedy, Gregory W.; Poe, Thomas P.

    1992-01-01

    Attempts to reestablish self-sustaining stocks of lake trout (Salvelinus namaycush) in the lower four Great Lakes, where the species was extinguished in the 1950s and 1960s, have been largely unsuccessful. To avoid many of the problems believed to be contributing to this failure, the fishery management community recently established several sanctuaries in the offshore waters of the Great Lakes where the development and protection of self-sustaining stocks of lake trout would be a primary management objective. One of these, the Six Fathom Bank-Yankee Reef sanctuary, was created in the south-central portion of Lake Huron. This sanctuary covers 168,000 ha and includes the shallower portions of the Six Fathom and Ipperwash scarps, which are major bathymetric features in the southern half of the lake. Historical accounts describe Six Fathom Bank as the most important lake trout spawning ground in the lake. Here we present the results of lake bed surveys conducted in the sanctuary with side-scan sonar, underwater videocamera systems, and a small research submarine. Our observations of the lake bed are consistent with what is known of the bedrock stratigraphy, glacial history, and karst geomorphology of the Lake Huron basin. Most of the loose rock we found seemed to be derived from local carbonate bedrock formations, although non-carbonate rock probably from Precambrian sources to the north was also present in some areas. Much of the bedrock and loose rock displayed karst solution features described for the Bruce Peninsula on the Ontario shoreline. Our surveys revealed substantial areas of lake bed at water depths of 20–36 m that resembled suitable spawning and fry production habitat for the shallow-water strains of lake trout that are the focus of the rehabilitation effort. Low mid-lake nutrient levels documented recently by others and the extremely high abundance of Mysis relicta (an important item in the diet of young lake trout) that we documented on Yankee Reef

  7. Lake-level variability and water availability in the Great Lakes

    USGS Publications Warehouse

    Wilcox, Douglas A.; Thompson, Todd A.; Booth, Robert K.; Nicholas, J.R.

    2007-01-01

    In this report, we present recorded and reconstructed (pre-historical) changes in water levels in the Great Lakes, relate them to climate changes of the past, and highlight major water-availability implications for storage, coastal ecosystems, and human activities. 'Water availability,' as conceptualized herein, includes a recognition that water must be available for human and natural uses, but the balancing of how much should be set aside for which use is not discussed. The Great Lakes Basin covers a large area of North America. The lakes capture and store great volumes of water that are critical in maintaining human activities and natural ecosystems. Water enters the lakes mostly in the form of precipitation and streamflow. Although flow through the connecting channels is a primary output from the lakes, evaporation is also a major output. Water levels in the lakes vary naturally on timescales that range from hours to millennia; storage of water in the lakes changes at the seasonal to millennial scales in response to lake-level changes. Short-term changes result from storm surges and seiches and do not affect storage. Seasonal changes are driven by differences in net basin supply during the year related to snowmelt, precipitation, and evaporation. Annual to millennial changes are driven by subtle to major climatic changes affecting both precipitation (and resulting streamflow) and evaporation. Rebounding of the Earth's surface in response to loss of the weight of melted glaciers has differentially affected water levels. Rebound rates have not been uniform across the basin, causing the hydrologic outlet of each lake to rise in elevation more rapidly than some parts of the coastlines. The result is a long-term change in lake level with respect to shoreline features that differs from site to site. The reconstructed water-level history of Lake Michigan-Huron over the past 4,700 years shows three major high phases from 2,300 to 3,300, 1,100 to 2,000, and 0 to 800

  8. Geologic map of the Cochetopa Park and North Pass Calderas, northeastern San Juan Mountains, Colorado

    USGS Publications Warehouse

    Lipman, Peter W.

    2012-01-01

    The San Juan Mountains in southwestern Colorado have long been known as a site of exceptionally voluminous mid-Tertiary volcanism, including at least 22 major ignimbrite sheets (each 150-5,000 km3) and associated caldera structures active at 33-23 Ma. Recent volcanologic and petrologic studies in the San Juan region have focused mainly on several ignimbrite-caldera systems: the southeastern area (Platoro complex), western calderas (Uncompahgre-Silverton-Lake City), and the central cluster (La Garita-Creede calderas). Far less studied has been the northeastern San Juan region, which occupies a transition between earlier volcanism in central Colorado and large-volume younger ignimbrite-caldera foci farther south and west. The present map is based on new field coverage of volcanic rocks in seventeen 7.5' quadrangles in northeastern parts of the volcanic field, high-resolution age determinations for 120 new sites, and petrologic studies involving several hundred new chemical analyses. This mapping and the accompanying lab results (1) document volcanic evolution of the previously unrecognized North Pass caldera and the morphologically beautifully preserved but enigmatic Cochetopa basin, including unique features not previously described from ignimbrite calderas elsewhere; (2) provide evidence for a more rapid recurrence of large ignimbrite eruptions than previously known elsewhere; (3) quantify the regional time-space-volume progression from the earlier Sawatch magmatic trend southward into the San Juan region; and (4) permit more rigorous comparison between the broad mid-Tertiary magmatic belt in the western U.S. Cordillera and the type continental-margin arc volcanism in the central Andes.

  9. Colorado Children's Budget 2013

    ERIC Educational Resources Information Center

    Buck, Beverly; Baker, Robin

    2013-01-01

    The "Colorado Children's Budget" presents and analyzes investments and spending trends during the past five state fiscal years on services that benefit children. The "Children's Budget" focuses mainly on state investment and spending, with some analysis of federal investments and spending to provide broader context of state…

  10. 76 FR 43719 - Notice of Inventory Completion: University of Colorado Museum, Boulder, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-21

    ...: University of Colorado Museum, Boulder, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The University of Colorado Museum has completed an inventory of human remains, in consultation with... to be culturally affiliated with the human remains may contact the University of Colorado Museum...

  11. Lake Life.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

    This quarterly publication of the State Historical Society of Iowa features articles and activities for elementary school students. This summer issue focuses on the topic of lake life. The issue includes the following features: (1) "Where the Lakes Are Map"; (2) "Letter from the Lake"; (3) "Lake People"; (4)…

  12. Increased piscivory by lake whitefish in Lake Huron

    USGS Publications Warehouse

    Pothoven, Steven A.; Madenjian, Charles P.

    2013-01-01

    We evaluated the diet of Lake Whitefish Coregonus clupeaformis in Lake Huron during 2002–2011 to determine the importance of Round Goby Neogobius melanostomus and other fish as prey items. Lake Whitefish that had reached approximately 400 mm in length incorporated fish into their diets. The overall percentage of adult Lake Whitefish in Lake Huron that had eaten fish increased from 10% in 2002–2006 to 20% in 2007–2011, with a corresponding decrease in the frequency of Lake Whitefish that ate Dreissena spp. from 52% to 33%. During 2002–2006, Round Goby (wet mass, 38%), sculpins (Cottidae) (34%), and Ninespine Stickleback Pungitius pungitius (18%) were the primary fish eaten, whereas Round Goby accounted for 92% of the fish eaten in 2007–2011. Overall, Round Goby were found in the fewest Lake Whitefish stomachs in the north region of Lake Huron (6%) and in the most in the central (23%) and south (19%) regions of the lake. In the central region, Round Goby were eaten during all seasons that were sampled (spring through fall). In the south region, Round Goby were eaten only in the winter and spring but not in the summer when Dreissena spp. and spiny water flea Bythotrephes longimanus dominated the diet. Based on the 2007–2011 diet composition, an individual Lake Whitefish would need to have increased their consumption relative to that in 1983–1994 by 6% in the north region, 12% in the central region, and 41% in the southern region in order to achieve the same growth that was observed before dreissenid mussels arrived. However, Lake Whitefish weight adjusted for length only increased by 2% between 2002–2006 and 2007–2011 in the central region, decreased by 4% in the northern region, and remained constant in the southern region. This suggests that a shift toward more frequent piscivory does not necessarily improve the condition of a generalist feeder like Lake Whitefish.

  13. The Colorado Plateau II: biophysical, socioeconomic, and cultural research

    USGS Publications Warehouse

    Mattson, David J.; van Riper, Charles

    2005-01-01

    The publication of The Colorado Plateau: Cultural, Biological, and Physical Research in 2004 marked a timely summation of current research in the Four Corners states. This new volume, derived from the seventh Biennial Conference on the Colorado Plateau in 2003, complements the previous book by focusing on the integration of science into resource management issues. The 32 chapters range in content from measuring human impacts on cultural resources, through grazing and the wildland-urban interface issues, to parameters of climate change on the Plateau. The book also introduces economic perspectives by considering shifting patterns and regional disparities in the Colorado Plateau economy. A series of chapters on mountain lions explores the human-wildland interface. These chapters deal with the entire spectrum of challenges associated with managing this large mammal species in Arizona and on the Colorado Plateau, conveying a wealth of timely information of interest to wildlife managers and enthusiasts. Another provocative set of chapters on biophysical resources explores the management of forest restoration, from the micro scale all the way up to large-scale GIS analyses of ponderosa pine ecosystems on the Colorado Plateau. Given recent concerns for forest health in the wake of fires, severe drought, and bark-beetle infestation, these chapters will prove enlightening for forest service, park service, and land management professionals at both the federal and state level, as well as general readers interested in how forest management practices will ultimately affect their recreation activities. With broad coverage that touches on topics as diverse as movement patterns of rattlesnakes, calculating watersheds, and rescuing looted rockshelters, this volume stands as a compendium of cutting-edge research on the Colorado Plateau that offers a wealth of insights for many scholars.

  14. An introduction to the Colorado Plateau Native Plant Initiative

    Treesearch

    Wayne Padgett; Peggy Olwell; Scott Lambert

    2010-01-01

    The Colorado Plateau Ecoregion is occupied by a variety of ecosystems requiring restoration activities following natural and human-caused disturbances. The Colorado Plateau Native Plant Initiative, included in the BLM Native Plant Materials Development Program, was established as a part of the Seeds of Success program. This program is a partnership between USDI Bureau...

  15. Holocene lake-level fluctuations of Lake Aricota, Southern Peru

    USGS Publications Warehouse

    Placzek, C.; Quade, Jay; Betancourt, J.L.

    2001-01-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17?? 22???S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ???2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16?? S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes. ?? 2001 University of Washington.

  16. Holocene Lake-Level Fluctuations of Lake Aricota, Southern Peru

    NASA Astrophysics Data System (ADS)

    Placzek, Christa; Quade, Jay; Betancourt, Julio L.

    2001-09-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17° 22‧S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ∼2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16°S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes.

  17. Reevaluation of lake trout and lake whitefish bioenergetics models

    USGS Publications Warehouse

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  18. Investigations of the Effects of Synthetic Chemicals on the Endocrine System of Common Carp in Lake Mead, Nevada and Arizona

    USGS Publications Warehouse

    Rosen, Michael R.; Goodbred, Steven L.; Patiño, Reynaldo; Leiker, Thomas A.; Orsak, Erik

    2006-01-01

    Introduction: Lake Mead is the largest reservoir by volume in the United States and was created by the construction of the 221-meter high Hoover Dam in 1935 at Black Canyon on the lower Colorado River between Nevada and Arizona (fig. 1). Inflows of water into the lake include three rivers, Colorado, Virgin, and Muddy; as well as Las Vegas Wash, which is now perennial because of discharges from municipal wastewater treatment plants (Covay and Leiker, 1998) and urban stormwater runoff. As the population within the Las Vegas Valley began to increase in the 1940s, the treated effluent volume also has increased and in 1993 it constituted about 96 percent of the annual discharge of Las Vegas Wash (Bevans and others, 1996). The mean flow of Las Vegas Wash into Las Vegas Bay from 1992 to 1998 was about 490,000 m3/d (Preissler and others, 1999) and in 2001 increased to 606,000 m3/d (U.S. Bureau of Reclamation, 2001). The nutrient concentration in most areas of the lake is low, but wastewater discharged into Las Vegas Bay has caused an increased level of nutrients and primary productivity (aquatic plant and algal production) in this area of the lake (LaBounty and Horn, 1997). A byproduct of this increase in productivity has been the establishment of an important recreational fishery in Las Vegas Bay. However, concentrations of chlorophyll a (a measure of algal biomass) have also increased (LaBounty and Horn, 1997). In the spring of 2001, parts of Lake Mead experienced massive algal blooms. In addition to nutrient loading by wastewater, the presence of numerous synthetic chemicals in water, bottom sediments, and in fish tissue also has been reported (Bevans and others, 1996). Synthetic chemicals discharging into Las Vegas Bay and Lake Mead (fig. 1) originate from several sources that include surplus residential-irrigation water runoff, stormwater runoff, subsurface inflow, and tertiary treated sewage effluent discharging from three sewage-treatment plants. Chemicals detected

  19. 75 FR 30852 - Hydroelectric Power Development at Ridgway Dam, Dallas Creek Project, Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... Gold, Assistant Regional Director, Upper Colorado Region. [FR Doc. 2010-13149 Filed 6-1-10; 8:45 am..., Dallas Creek Project, Colorado AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of intent to..., Area Manager, Western Colorado Area Office, Bureau of Reclamation, 2764 Compass Drive, Suite 106, Grand...

  20. Late Holocene lake-level fluctuations in Walker Lake, Nevada, USA

    USGS Publications Warehouse

    Yuan, F.; Linsley, B.K.; Howe, S.S.; Lund, S.P.; McGeehin, J.P.

    2006-01-01

    Walker Lake, a hydrologically closed, saline, and alkaline lake, is situated along the western margin of the Great Basin in Nevada of the western United States. Analyses of the magnetic susceptibility (??), total inorganic carbon (TIC), and oxygen isotopic composition (??18O) of carbonate sediments including ostracode shells (Limnocythere ceriotuberosa) from Walker Lake allow us to extend the sediment record of lake-level fluctuations back to 2700??years B.P. There are approximately five major stages over the course of the late Holocene hydrologic evolution in Walker Lake: an early lowstand (> 2400??years B.P.), a lake-filling period (??? 2400 to ??? 1000??years B.P.), a lake-level lowering period during the Medieval Warm Period (MWP) (??? 1000 to ??? 600??years B.P.), a relatively wet period (??? 600 to ??? 100??years B.P.), and the anthropogenically induced lake-level lowering period (< 100??years B.P.). The most pronounced lowstand of Walker Lake occurred at ??? 2400??years B.P., as indicated by the relatively high values of ??18O. This is generally in agreement with the previous lower resolution paleoclimate results from Walker Lake, but contrasts with the sediment records from adjacent Pyramid Lake and Siesta Lake. The pronounced lowstand suggests that the Walker River that fills Walker Lake may have partially diverted into the Carson Sink through the Adrian paleochannel between 2700 to 1400??years B.P. ?? 2006 Elsevier B.V. All rights reserved.

  1. Mesoscale variability of the Upper Colorado River snowpack

    USGS Publications Warehouse

    Ling, C.-H.; Josberger, E.G.; Thorndike, A.S.

    1996-01-01

    In the mountainous regions of the Upper Colorado River Basin, snow course observations give local measurements of snow water equivalent, which can be used to estimate regional averages of snow conditions. We develop a statistical technique to estimate the mesoscale average snow accumulation, using 8 years of snow course observations. For each of three major snow accumulation regions in the Upper Colorado River Basin - the Colorado Rocky Mountains, Colorado, the Uinta Mountains, Utah, and the Wind River Range, Wyoming - the snow course observations yield a correlation length scale of 38 km, 46 km, and 116 km respectively. This is the scale for which the snow course data at different sites are correlated with 70 per cent correlation. This correlation of snow accumulation over large distances allows for the estimation of the snow water equivalent on a mesoscale basis. With the snow course data binned into 1/4?? latitude by 1/4?? longitude pixels, an error analysis shows the following: for no snow course data in a given pixel, the uncertainty in the water equivalent estimate reaches 50 cm; that is, the climatological variability. However, as the number of snow courses in a pixel increases the uncertainty decreases, and approaches 5-10 cm when there are five snow courses in a pixel.

  2. Bathythermal habitat use by strains of Great Lakes- and Finger Lakes-origin lake trout in Lake Huron after a change in prey fish abundance and composition

    USGS Publications Warehouse

    Bergstedt, Roger A.; Argyle, Ray L.; Krueger, Charles C.; Taylor, William W.

    2012-01-01

    A study conducted in Lake Huron during October 1998–June 2001 found that strains of Great Lakes-origin (GLO) lake trout Salvelinus namaycush occupied significantly higher temperatures than did Finger Lakes-origin (FLO; New York) lake trout based on data from archival (or data storage) telemetry tags that recorded only temperature. During 2002 and 2003, we implanted archival tags that recorded depth as well as temperature in GLO and FLO lake trout in Lake Huron. Data subsequently recorded by those tags spanned 2002–2005. Based on those data, we examined whether temperatures and depths occupied by GLO and FLO lake trout differed during 2002–2005. Temperatures occupied during those years were also compared with occupied temperatures reported for 1998–2001, before a substantial decline in prey fish biomass. Temperatures occupied by GLO lake trout were again significantly higher than those occupied by FLO lake trout. This result supports the conclusion of the previous study. The GLO lake trout also occupied significantly shallower depths than FLO lake trout. In 2002–2005, both GLO and FLO lake trout occupied significantly lower temperatures than they did in 1998–2001. Aside from the sharp decline in prey fish biomass between study periods, the formerly abundant pelagic alewife Alosa pseudoharengus virtually disappeared and the demersal round goby Neogobius melanostomus invaded the lake and became locally abundant. The lower temperatures occupied by lake trout in Lake Huron during 2002–2005 may be attributable to changes in the composition of the prey fish community, food scarcity (i.e., a retreat to cooler water could increase conversion efficiency), or both.

  3. Chemours Pompton Lakes Works Site, Pompton Lakes, NJ

    EPA Pesticide Factsheets

    E.I. DuPont De Nemours & Company is located at 2000 Cannonball Road, Pompton Lakes, New Jersey. The DuPont Pompton Lakes Works site (DuPont) occupies approximately 570 acres of land in Pompton Lakes and Wanaque.

  4. Selenium impacts on razorback sucker, Colorado River, Colorado II. Eggs.

    PubMed

    Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A

    2005-05-01

    Effects on hatching and development of fertilized eggs in adult razorback sucker (Xyrauchen texanus) exposed to selenium in flooded bottomland sites near Grand Junction, Colorado, were determined. After 9 months exposure, fish were collected and induced to spawn and eggs collected for inorganic element analyses. A 9-day egg study was conducted with five spawns from Horsethief ponds, six spawns from Adobe Creek channel, and four spawns from North Pond using a reference water and site waters. Selenium concentrations in eggs were 6.5 microg/g from Horsethief, 46 microg/g from Adobe Creek, 38 microg/g from North Pond, and 6.0 microg/g from brood stock. Eggs from young adults had a smaller diameter and higher moisture content than brood stock. There were no differences among the four sources in viability, survival, hatch, hatchability, or mortality of deformed embryos or larvae. Adobe Creek larvae had more deformed embryos in eggs held in site water than held in reference water. There were significant negative correlations between selenium concentrations in adult muscle plugs and percent hatch, egg diameter, and deformities in embryos. Results from this study suggest that selenium contamination in parts of the upper basin of the Colorado River should be a major concern to recovery efforts for endangered fish.

  5. Workforce Brief: Colorado

    ERIC Educational Resources Information Center

    Western Interstate Commission for Higher Education, 2006

    2006-01-01

    Employment in Colorado (including hourly and salaried jobs and self-employment) is projected to grow by 23 percent from 2002 to 2012, adding some 551,630 new jobs to the state's economy and growing the workforce from 2,355,290 to 2,906,920. The rate of growth is much higher than the 15 percent increase projected for the nation as a whole.…

  6. 43 CFR 431.7 - Administration and management of the Colorado River Dam Fund.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the administration of the Colorado River Dam Fund and the Lower Colorado River Basin Development Fund... deposited by Western and shall be available without further appropriation for: (1) Defraying the costs of... River Basin Project Act; (5) Transfers to the Lower Colorado River Basin Development Fund and subsequent...

  7. 30 CFR 906.25 - Approval of Colorado abandoned mine land reclamation plan amendments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Approval of Colorado abandoned mine land reclamation plan amendments. 906.25 Section 906.25 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STATE COLORADO § 906.25 Approval of Colorado abandoned mine land reclamation plan amendments. The...

  8. Colorado aqueduct system begins at impounded waters from Hoover Dam ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Colorado aqueduct system begins at impounded waters from Hoover Dam along with agreement made reserving use and ownership of several generators set to power pump houses downstream at Whitsett and beyond - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  9. 77 FR 61784 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-11

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Colorado River Basin Salinity Control Advisory... River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub. L. 93-320) (Act) to receive reports and advise Federal agencies on...

  10. 77 FR 23508 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Colorado River Basin Salinity Control Advisory... River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub. L. 93-320) (Act) to receive reports and advise Federal agencies on...

  11. 78 FR 23784 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-22

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Colorado River Basin Salinity Control Advisory... River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Public Law 93-320) (Act) to receive reports and advise Federal agencies on...

  12. 75 FR 66389 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-28

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Colorado River Basin Salinity Control Advisory... River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub. L. 93-320) (Act) to receive reports and advise Federal agencies on...

  13. 75 FR 27360 - Colorado River Basin Salinity Control Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-14

    ... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Colorado River Basin Salinity Control Advisory... River Basin Salinity Control Advisory Council (Council) was established by the Colorado River Basin Salinity Control Act of 1974 (Pub. L. 93-320) (Act) to receive reports and advise Federal agencies on...

  14. Competing risks and the development of adaptive management plans for water resources: Field reconnaissance investigation of risks to fishes and other aquatic biota exposed to endocrine disrupting chemicals (edcs) in lake mead, Nevada USA

    USGS Publications Warehouse

    Linder, G.; Little, E.E.

    2009-01-01

    The analysis and characterization of competing risks for water resources rely on a wide spectrum of tools to evaluate hazards and risks associated with their management. For example, waters of the lower Colorado River stored in reservoirs such as Lake Mead present a wide range of competing risks related to water quantity and water quality. These risks are often interdependent and complicated by competing uses of source waters for sustaining biological resources and for supporting a range of agricultural, municipal, recreational, and industrial uses. USGS is currently conducting a series of interdisciplinary case-studies on water quality of Lake Mead and its source waters. In this case-study we examine selected constituents potentially entering the Lake Mead system, particularly endocrine disrupting chemicals (EDCs). Worldwide, a number of environmental EDCs have been identified that affect reproduction, development, and adaptive behaviors in a wide range of organisms. Many EDCs are minimally affected by current treatment technologies and occur in treated sewage effluents. Several EDCs have been detected in Lake Mead, and several substances have been identified that are of concern because of potential impacts to the aquatic biota, including the sport fishery of Lake Mead and endangered razorback suckers (Xyrauchen texanus) that occur in the Colorado River system. For example, altered biomarkers relevant to reproduction and thyroid function in fishes have been observed and may be predictive of impaired metabolism and development. Few studies, however, have addressed whether such EDC-induced responses observed in the field have an ecologically significant effect on the reproductive success of fishes. To identify potential linkages between EDCs and species of management concern, the risk analysis and characterization in this reconnaissance study focused on effects (and attendant uncertainties) that might be expressed by exposed populations. In addition, risk reduction

  15. Porewater salinity reveals past lake-level changes in Lake Van, the Earth's largest soda lake.

    PubMed

    Tomonaga, Yama; Brennwald, Matthias S; Livingstone, David M; Kwiecien, Olga; Randlett, Marie-Ève; Stockhecke, Mona; Unwin, Katie; Anselmetti, Flavio S; Beer, Jürg; Haug, Gerald H; Schubert, Carsten J; Sturm, Mike; Kipfer, Rolf

    2017-03-22

    In closed-basin lakes, sediment porewater salinity can potentially be used as a conservative tracer to reconstruct past fluctuations in lake level. However, until now, porewater salinity profiles did not allow quantitative estimates of past lake-level changes because, in contrast to the oceans, significant salinity changes (e.g., local concentration minima and maxima) had never been observed in lacustrine sediments. Here we show that the salinity measured in the sediment pore water of Lake Van (Turkey) allows straightforward reconstruction of two major transgressions and a major regression that occurred during the last 250 ka. We observed strong changes in the vertical salinity profiles of the pore water of the uppermost 100 m of the sediments in Lake Van. As the salinity balance of Lake Van is almost at steady-state, these salinity changes indicate major lake-level changes in the past. In line with previous studies on lake terraces and with seismic and sedimentological surveys, we identify two major transgressions of up to +105 m with respect to the current lake level at about 135 ka BP and 248 ka BP starting at the onset of the two previous interglacials (MIS5e and MIS7), and a major regression of about -200 m at about 30 ka BP during the last ice age.

  16. Into the void: Regulating pesticide use in Colorado's commercial cannabis markets.

    PubMed

    Subritzky, Todd; Pettigrew, Simone; Lenton, Simon

    2017-04-01

    In 2014, Colorado implemented the world's first seed-to-sale recreational cannabis market under a commercial model. This paper aims to provide a thick descriptive account that gives insight into the issues and complexities of Colorado's pioneering and evolving attempt to regulate the use of pesticides on commercial cannabis plantations. The paper examines multiple data sets including: (i) Colorado State Government documents; (ii) recreational cannabis regulations; (iii) mass and niche media publications (n=175); (iv) face-to-face interviews with key stakeholders, including seniors, regulators and industry executives (n=8); and (v) field notes from relevant conferences and cultivation facility tours in Denver in October, 2016. Two key issues are identified. First, a public safety threat has arisen relating to application of pesticides on cannabis with intensified toxicity in concentrated products of particular concern. Second, as a pioneering jurisdiction, Colorado faces a considerable knowledge gap. To expand collective learning on this issue, for which no regulatory template and little research exists, state regulators tapped industry and other stakeholder expertise while attempting to ensure public safety goals were achieved and regulatory capture by industry was limited. Four years since the recreational cannabis market in Colorado was legalised, the State continues to grapple with the pesticide issue as testing regulations and cultivation standards are yet to be finalised. While more work is needed, Colorado has made significant progress in developing regulations relating to this complex matter. As governments of countries such as Canada and US states, including California, contemplate changes to recreational cannabis laws, Colorado's experience can assist regulators in other jurisdictions considering policy change. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Spatial and temporal genetic diversity of lake whitefish (Coregonus clupeaformis (Mitchill)) from Lake Huron and Lake Erie

    USGS Publications Warehouse

    Stott, Wendylee; Ebener, Mark P.; Mohr, Lloyd; Hartman, Travis; Johnson, Jim; Roseman, Edward F.

    2013-01-01

    Lake whitefish (Coregonus clupeaformis (Mitchill)) are important commercially, culturally, and ecologically in the Laurentian Great Lakes. Stocks of lake whitefish in the Great Lakes have recovered from low levels of abundance in the 1960s. Reductions in abundance, loss of habitat and environmental degradation can be accompanied by losses of genetic diversity and overall fitness that may persist even as populations recover demographically. Therefore, it is important to be able to identify stocks that have reduced levels of genetic diversity. In this study, we investigated patterns of genetic diversity at microsatellite DNA loci in lake whitefish collected between 1927 and 1929 (historical period) and between 1997 and 2005 (contemporary period) from Lake Huron and Lake Erie. Genetic analysis of lake whitefish from Lakes Huron and Erie shows that the amount of population structuring varies from lake to lake. Greater genetic divergences among collections from Lake Huron may be the result of sampling scale, migration patterns and demographic processes. Fluctuations in abundance of lake whitefish populations may have resulted in periods of increased genetic drift that have resulted in changes in allele frequencies over time, but periodic genetic drift was not severe enough to result in a significant loss of genetic diversity. Migration among stocks may have decreased levels of genetic differentiation while not completely obscuring stock boundaries. Recent changes in spatial boundaries to stocks, the number of stocks and life history characteristics of stocks further demonstrate the potential of coregonids for a swift and varied response to environmental change and emphasise the importance of incorporating both spatial and temporal considerations into management plans to ensure that diversity is preserved.

  18. Costs and savings associated with community water fluoridation programs in Colorado.

    PubMed

    O'Connell, Joan M; Brunson, Diane; Anselmo, Theresa; Sullivan, Patrick W

    2005-11-01

    Local, state, and national health policy makers require information on the economic burden of oral disease and the cost-effectiveness of oral health programs to set policies and allocate resources. In this study, we estimate the cost savings associated with community water fluoridation programs (CWFPs) in Colorado and potential cost savings if Colorado communities without fluoridation programs or naturally high fluoride levels were to implement CWFPs. We developed an economic model to compare the costs associated with CWFPs with treatment savings achieved through averted tooth decay. Treatment savings included those associated with direct medical costs and indirect nonmedical costs (i.e., patient time spent on dental visit). We estimated program costs and treatment savings for each water system in Colorado in 2003 dollars. We obtained parameter estimates from published studies, national surveys, and other sources. We calculated net costs for Colorado water systems with existing CWFPs and potential net costs for systems without CWFPs. The analysis includes data for 172 public water systems in Colorado that serve populations of 1000 individuals or more. We used second-order Monte Carlo simulations to evaluate the inherent uncertainty of the model assumptions on the results and report the 95% credible range from the simulation model. We estimated that Colorado CWFPs were associated with annual savings of 148.9 million dollars (credible range, 115.1 million dollars to 187.2 million dollars) in 2003, or an average of 60.78 dollars per person (credible range, 46.97 dollars dollars to 76.41 dollars). We estimated that Colorado would save an additional 46.6 million dollars (credible range, 36.0 dollars to 58.6 dollars million) annually if CWFPs were implemented in the 52 water systems without such programs and for which fluoridation is recommended. Colorado realizes significant annual savings from CWFPs; additional savings and reductions in morbidity could be achieved if

  19. Susceptibility to Myxobolus cerebralis among Tubifex tubifex populations from ten major drainage basins in Colorado where Cutthroat Trout are endemic.

    PubMed

    Nehring, R Barry; Lukacs, P M; Baxa, D V; Stinson, M E T; Chiaramonte, L; Wise, S K; Poole, B; Horton, A

    2014-03-01

    Establishment of Myxobolus cerebralis (Mc) resulted in declines of wild Rainbow Trout Oncorhynchus mykiss populations in streams across Colorado during the 1990s. However, the risk for establishment and spread of this parasite into high-elevation habitats occupied by native Cutthroat Trout O. clarkii was unknown. Beginning in 2003, tubificid worms were collected from all major drainages where Cutthroat Trout were endemic and were assayed by quantitative PCR to determine the occurrence and distribution of the various lineages of Tubifex tubifex (Tt) oligochaetes. Over a 5-year period, 40 groups of Tt oligochaetes collected from 27 streams, 3 natural lakes, 2 private ponds, and a reservoir were evaluated for their relative susceptibility to Mc. Exposure groups were drawn from populations of pure lineage III Tt, mixed-lineage populations where one or more of the highly resistant (lineage I) or nonsusceptible lineages (V or VI) were the dominant oligochaete and susceptible lineage III worms were the subdominant worm, or pure lineage VI Tt. Experimental replicates of 250 oligochaetes were exposed to 50 Mc myxospores per worm. The parasite amplification ratio (total triactinomyxons [TAMs] produced / total myxospore exposure) was very high among all pure lineage III Colorado exposure groups, averaging 363 compared with 8.24 among the mixed-lineage exposure groups. Lineage III oligochaetes from Mt. Whitney Hatchery in California, which served as the laboratory standard for comparative purposes, had an average parasite amplification ratio of 933 among 10 exposed replicates over a 5-year period. Lineage I oligochaetes were highly resistant to infection and did not produce any TAMs. Lineages V and VI Tt did not become infected and did not produce any TAMs. These results suggest that the risk of establishment of Mc is high for aquatic habitats in Colorado where Cutthroat Trout and lineage III Tt are sympatric.

  20. MIGRATORY LABOR IN COLORADO.

    ERIC Educational Resources Information Center

    DOUGLASS, M.R.; AND OTHERS

    CONDITIONS AND PROBLEMS RELATING TO THE EMPLOYMENT OF SEASONAL FARM WORKERS AND MIGRANTS IN COLORADO ARE PRESENTED. THE FIVE MAJOR SEASONAL FARM LABOR STATE EMPLOYMENT AREAS ARE SURVEYED ACCORDING TO (1) THE ORGANIZATION OF THE SEASONAL FARM LABOR (4) TRENDS IN AGRICULTURAL ACREAGE, PRODUCTION, AND TECHNOLOGICAL CHANGE, (5) COMMUNITY ATTITUDES AND…

  1. Colorado Children's Budget 2010

    ERIC Educational Resources Information Center

    Colorado Children's Campaign, 2010

    2010-01-01

    The "Children's Budget 2010" is intended to be a resource guide for policymakers and advocates who are interested in better understanding how Colorado funds children's programs and services. It attempts to clarify often confusing budget information and describe where the state's investment trends are and where those trends will lead the…

  2. Colorado gains excess capacity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stremel, K.

    1984-03-01

    Colorado has gained the majority of new natural gas processing and gathering facilities in the southern Rocky Mountain area. Seven new plants in the Denver-Julesburg Basin have nearly doubled the previous unused design capacity. This paper discusses the development and exploitation of these new facilities and some of the designs.

  3. Policy Analysis for Rural Development and Growth Management in Colorado.

    ERIC Educational Resources Information Center

    Gilmore, John S.; Duff, Mary K.

    Providing a broad analysis of Colorado's rural problems, the body of this report enumerates rural development and growth management problems; describes remedies worth study; and suggests a policy making system. The Appendix presents supporting material, including comparative socioeconomic data on each Colorado county. Opportunities and threats…

  4. 30 CFR 906.15 - Approval of Colorado regulatory program amendments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Approval of Colorado regulatory program amendments. 906.15 Section 906.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PROGRAMS FOR THE CONDUCT OF SURFACE MINING OPERATIONS WITHIN EACH STATE COLORADO...

  5. Late Quaternary loess in northeastern Colorado: Part I - Age and paleoclimatic significance

    USGS Publications Warehouse

    Muhs, D.R.; Aleinikoff, J.N.; Stafford, Thomas W.; Kihl, R.; Been, J.; Mahan, S.A.; Cowherd, S.

    1999-01-01

    Loess in eastern Colorado covers an estimated 14000 km2, and is the westernmost part of the North American midcontinent loess province. Stratigraphic studies indicate there were two periods of loess deposition in eastern Colorado during late Quaternary time. The first period spanned ca. 20 000 to 12 000 14C yr B.P. (ca. 20-14 ka) and correlates reasonably well with the culmination and retreat of Pinedale glaciers in the Colorado Front Range during the last glacial maximum. The second period of loess deposition occurred between ca. 11 000 and 9000 14C yr B.P. This interval may be Holocene or may correlate with a hypothesized Younger Dryas glacial advance in the Colorado Front Range. Sedimentologic, mineralogic, and geochemical data indicate that as many as three sources could have supplied loess in eastern Colorado. These sources include glaciogenic silt (derived from the Colorado Front Range) and two bedrock sources, volcaniclastic silt from the White River Group, and clays from the Pierre Shale. The sediment sources imply a generally westerly paleowind during the last glacial maximum. New carbon isotope data, combined with published faunal data, indicate that the loess was probably deposited on a cool steppe, implying a last glacial maximum July temperature depression, relative to the present, of at least 5-6??C. Overall, loess deposition in eastern Colorado occurred mostly toward the end of the last glacial maximum, under cooler and drier conditions, with generally westerly winds from more than one source.

  6. Soil moisture ground truth: Steamboat Springs, Colorado, site and Walden, Colorado, site

    NASA Technical Reports Server (NTRS)

    Jones, E. B.

    1976-01-01

    Ground-truth data taken at Steamboat Springs and Walden, Colorado in support of the NASA missions in these areas during the period March 8, 1976 through March 11, 1976 was presented. This includes the following information: snow course data for Steamboat Springs and Walden, snow pit and snow quality data for Steamboat Springs, and soil moisture report.

  7. 75 FR 9370 - Safety Zone; AVI May Fireworks Display, Colorado River, Laughlin, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-02

    ...-AA00 Safety Zone; AVI May Fireworks Display, Colorado River, Laughlin, NV AGENCY: Coast Guard, DHS... waters of the lower Colorado River, Laughlin, NV, in support of a fireworks display near the AVI Resort... navigable waters of the Lower Colorado River in support of a fireworks show near Laughlin, NV. The fireworks...

  8. Removal of pinyon-juniper woodlands on the Colorado Plateau

    Treesearch

    Michael Peters; Neil S. Cobb

    2008-01-01

    (Please note, this is an abstract only) Pinyon-Juniper (PJ) woodland is the 3rd largest vegetation type in the United States, covering 35.5% of the Colorado Plateau, it is the largest vegetation type administered by the Bureau of Land Management (BLM) on the Colorado Plateau. These woodlands have been increasing dramatically in density and extent over the last 100...

  9. Movements of hatchery-reared lake trout in Lake Superior

    USGS Publications Warehouse

    Pycha, Richard L.; Dryer, William R.; King, George R.

    1965-01-01

    The history of stocking of lake trout (Salvelinus namaycush) in the Great Lakes is reviewed. The study of movements is based on capture of 24,275 fin-clipped lake trout taken in experimental gill nets and trawls and commercial gill nets. Yearling lake trout planted from shore dispersed to 15-fath (27-m) depths in 3A? hr. Most fish remained within 2 miles (3.2 km) of the planting site 2 months, but within 4 months some fish had moved as much as 17 miles (27 km). The highest abundance of planted lake trout was in areas 2-4 miles (3.2-6.4 km) from the planting site even 3 years after release. Distance moved and size of fish were not correlated. Dispersal of lake trout begins at planting and probably continues until the fish are mature. Most movement was eastward in southern Lake Superior and followed the counterclockwise surface currents. Movement is most rapid in areas of strong currents and slowest in areas of weak currents or eddies. Movement to areas west of the Keweenaw Peninsula was insignificant from plantings in Keweenaw Bay and nil from other plantings farther east. Lake trout planted in the eastern third of the lake dispersed more randomly than those planted farther west. Few fish moved farther offshore than the 50-fath (91-m) contour. Lake trout planted in Canadian waters made insignificant contributions to populations in US waters.

  10. Colorado Plateau rock strength, exhumation, and river knickzones - spatial datasets relating erodability to topographic metrics

    NASA Astrophysics Data System (ADS)

    Tressler, C.; Pederson, J. L.

    2009-12-01

    above Lake Mead. Using GIS, we map rock strength with respect to our existing estimate of mid-late Cenozoic exhumation, and calculate river-profile convexity and ks. Hydrogeomorphic models commonly assume that discharge along a system can be directly approximated through contributing area. However, the Colorado River system is an example where this assumption is invalid due to its downstream progression through increasingly arid terrain. This problem results in increasingly distorted values of long-profile metrics downstream. To address this, we develop an adjusted flow-accumulation grid that is calibrated using the pre-dam effective discharge of the Colorado River recorded at gauging stations. Initial results indicate rock strength and topographic metrics are strongly correlated in the middle-lower reaches of the plateau drainage. In this dry setting, we suggest topography and channel steepness are strongly linked to rock type. This linkage is less clear approaching lower order drainages and within the Rocky Mountain flank, where knickzones appear to insulate gentle headwaters. The pattern of exhumation across the region also suggests the primary signal of baselevel fall has passed through the heart of the Colorado Plateau, with possible transient knickzones along its mountainous rim.

  11. Assessment of water quality, road runoff, and bulk atmospheric deposition, Guanella Pass area, Clear Creek and Park Counties, Colorado, water years 1995-97

    USGS Publications Warehouse

    Stevens, Michael R.

    2001-01-01

    The Guanella Pass road, located about 40 miles west of Denver, Colorado, between the towns of Georgetown and Grant, has been designated a scenic byway and is being considered for reconstruction. The purpose of this report is to present an assessment of hydrologic and water-quality conditions in the Guanella Pass area and provide baseline data for evaluation of the effects of the proposed road reconstruction. The data were collected during water years 1995-97 (October 1, 1995, to September 30, 1997).Based on Colorado water-quality standards, current surface-water quality near Guanella Pass road was generally acceptable for specified use classifications of recreation, water supply, agriculture, and aquatic life. Streams had small concentrations of dissolved solids, nutrients, trace elements, and suspended sediment. An exception was upper Geneva Creek, which was acidic and had relatively large concentrations of iron, zinc, and other trace elements related to acid-sulfate weathering. Concentrations of many water-quality constituents, especially particle-related phases and suspended sediment, increased during peak snowmelt and rainstorm events and decreased to prerunoff concentrations at the end of runoff periods. Some dissolved (filtered) trace-element loads in Geneva Creek decreased during rainstorms when total recoverable loads remained generally static or increased, indicating a phase change that might be explained by adsorption of trace elements to suspended sediment during storm runoff.Total recoverable iron and dissolved zinc exceeded Colorado stream-water-quality standards most frequently. Exceedances for iron generally occurred during periods of high suspended-sediment transport in several streams. Zinc standards were exceeded in about one-half the samples collected in Geneva Creek 1.5 miles upstream from Grant.Lake-water quality was generally similar to that of area streams. Nitrogen and phosphorus ratios calculated for Clear and Duck Lakes indicated that

  12. Final Environmental Assessment for New Golf Driving Range at Buckley Air Force Base, Colorado

    DTIC Science & Technology

    2002-11-01

    Guide To Colorado Wildflowers, Volume 1: Plains and Foothills. Westcliffe Publishers, Inc., Englewood, CO. Littell, Richard, 1992. Endangered and Other...Wittmann, 2001. Colorado Flora: Eastern Slope. University Press of Colorado, Boulder, CO. Wingate, Janet, 1994. Illustrated Keys to the Grasses of

  13. Residential Energy Efficiency Potential: Colorado

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wilson, Eric J

    Energy used by Colorado single-family homes that can be saved through cost-effective improvements. Prepared by Eric Wilson and Noel Merket, NREL, and Erin Boyd, U.S. Department of Energy Office of Energy Policy and Systems Analysis.

  14. Transportation enhancement guidelines : Colorado supplement

    DOT National Transportation Integrated Search

    2000-10-10

    Under the Transportation Equity Act for the 21st Century (TEA-21), the states were given funds to enhance their transportation infrastructures, following basic guidelines set up in the law. The Colorado Department of Transportation (CDOT) developed t...

  15. Colorado oil shale: the current status, October 1979

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    1979-01-01

    A general background to oil shale and the potential impacts of its development is given. A map containing the names and locations of current oil shale holdings is included. The history, geography, archaeology, ecology, water resources, air quality, energy resources, land use, sociology, transportation, and electric power for the state of Colorado are discussed. The Colorado Joint Review Process Stages I, II, and III-oil shale are explained. Projected shale oil production capacity to 1990 is presented. (DC)

  16. Colorado Schools Chief, Local Superintendents Spar over Role of State

    ERIC Educational Resources Information Center

    McNeil, Michele

    2006-01-01

    Colorado's 178 district superintendents are embroiled in a polite, yet pointed debate with Commissioner of Education William J. Moloney and the state school board over the state's role in helping districts raise student achievement. In this article, the author discusses Colorado district superintendents' grievances. They are calling for more…

  17. Geothermal Target Areas in Colorado as Identified by Remote Sensing Techniques

    DOE Data Explorer

    Khalid Hussein

    2012-02-01

    This layer contains the areas identified as targets of potential geothermal activity. The Criteria used to identify the target areas include: hot/warm surface exposures modeled from ASTER/Landsat satellite imagery and geological characteristics, alteration mineral commonly associated with hot springs (clays, Si, and FeOx) modeled from ASTER and Landsat data, Colorado Geological Survey (CGS) known thermal hot springs/wells and heat-flow data points, Colorado deep-seated fault zones, weakened basement identified from isostatic gravity data, and Colorado sedimentary and topographic characteristics.

  18. Energy density of lake whitefish Coregonus clupeaformis in Lakes Huron and Michigan

    USGS Publications Warehouse

    Pothoven, S.A.; Nalepa, T.F.; Madenjian, C.P.; Rediske, R.R.; Schneeberger, P.J.; He, J.X.

    2006-01-01

    We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.

  19. 77 FR 51792 - Colorado Interstate Gas Company, L.L.C.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-27

    ... Interstate Gas Company, L.L.C.; Notice of Application Take notice that on August 7, 2012, Colorado Interstate Gas Company, L.L.C. (CIG), Post Office Box 1087, Colorado Springs, Colorado 80944, filed in the above captioned docket an application pursuant to section 7(c) of the Natural Gas Act (NGA) for a certificate of...

  20. Late glacial aridity in southern Rocky Mountains

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Davis, O K; Pitblado, B L

    While the slopes of the present-day Colorado Rocky Mountains are characterized by large stands of subalpine and montane conifers, the Rockies of the late glacial looked dramatically different. Specifically, pollen records suggest that during the late glacial, Artemisia and Gramineae predominated throughout the mountains of Colorado. At some point between 11,000 and 10,000 B.P., however, both Artemisia and grasses underwent a dramatic decline, which can be identified in virtually every pollen diagram produced for Colorado mountain sites, including Como Lake (Sangre de Cristo Mountains), Copley Lake and Splains; Gulch (near Crested Butte), Molas Lake (San Juan Mountains), and Redrock Lakemore » (Boulder County). Moreover, the same pattern seems to hold for pollen spectra derived for areas adjacent to Colorado, including at sites in the Chuska Mountains of New Mexico and in eastern Wyoming. The implications of this consistent finding are compelling. The closest modem analogues to the Artemisia- and Gramineae-dominated late-glacial Colorado Rockies are found in the relatively arid northern Great Basin, which suggests that annual precipitation was much lower in the late-glacial southern Rocky Mountains than it was throughout the Holocene.« less

Some links on this page may take you to non-federal websites. Their policies may differ from this site.