75 FR 44809 - Glen Canyon Dam Adaptive Management Work Group (AMWG)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-29

... Canyon Dam Adaptive Management Program (AMP) was implemented as a result of the Record of Decision on the... of the Grand Canyon Protection Act (Pub. L. 102-575) of 1992. The AMP includes a Federal advisory... other administrative and resource issues pertaining to the AMP. To view a copy of the agenda and...

75 FR 439 - Glen Canyon Dam Adaptive Management Work Group (AMWG)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-05

... Canyon Dam Adaptive Management Program (AMP) was implemented as a result of the Record of Decision on the... of the Grand Canyon Protection Act (Pub. L. 102-575) of 1992. The AMP includes a Federal advisory... addition, other administrative and resource issues pertaining to the AMP may be discussed as necessary. To...

Three Experimental High-Flow Releases from Glen Canyon Dam, Arizona-Effects on the Downstream Colorado River Ecosystem

USGS Publications Warehouse

Melis, Theodore S.; Grams, Paul E.; Kennedy, Theodore A.; Ralston, Barbara E.; Robinson, Christopher T.; Schmidt, John C.; Schmit, Lara M.; Valdez, Richard A.; Wright, Scott A.

2011-01-01

Three high-flow experiments (HFEs) were conducted by the U.S. Department of the Interior at Glen Canyon Dam, Arizona, in March 1996, November 2004, and March 2008. Also known as artificial or controlled floods, these scheduled releases of water above the dam's powerplant capacity were designed to mimic pre-dam seasonal flooding on the Colorado River. The goal of the HFEs was to determine whether high flows could be used to benefit important downstream resources in Glen Canyon National Recreation Area and Grand Canyon National Park that have been affected by the existence and operation of Glen Canyon Dam. These downstream resources include native fish, particularly endangered humpback chub (Gila cypha), terrestrial and aquatic sandbar habitats, cultural sites, and recreational resources. This Fact Sheet summarizes HFE-related studies published since 1996 and outlines a possible strategy for implementing future HFEs.

Effects of three high-flow experiments on the Colorado River ecosystem downstream from Glen Canyon Dam, Arizona

USGS Publications Warehouse

Melis, Theodore S.

2011-01-01

Three high-flow experiments (HFEs) were conducted by the U.S. Department of the Interior at Glen Canyon Dam, Arizona, in March 1996, November 2004, and March 2008. These experiments, also known as artificial or controlled floods, were large-volume, scheduled releases of water from Glen Canyon Dam that were designed to mimic some aspects of pre-dam Colorado River seasonal flooding. The goal of these experiments was to determine whether high flows could be used to benefit important physical and biological resources in Glen Canyon National Recreation Area and Grand Canyon National Park that had been affected by the operation of Glen Canyon Dam. Efforts such as HFEs that seek to maintain and restore downstream resources are undertaken by the U.S. Department of the Interior under the auspices of the Grand Canyon Protection Act of 1992 (GCPA; title XVIII, secs. 1801-1809, of Public Law 102-575). Scientists conducted a wide range of monitoring and research activities before, during, and after the experiments. Initially, research efforts focused on whether HFEs could be used to rebuild and maintain Grand Canyon sandbars, which provide camping beaches for hikers and whitewater rafters, create habitats potentially used by native fish and other wildlife, and are the source of windborne sand that may help to protect some archaeological resources from weathering and erosion. As scientists gained a better understanding of how HFEs affect the physical environment, research efforts expanded to include additional investigations about the effects of HFEs on biological resources, such as native fishes, nonnative sports fishes, riverside vegetation, and the aquatic food web. The chapters that follow summarize and synthesize for decisionmakers and the public what has been learned about HFEs to provide a framework for implementing similar future experiments. This report is a product of the Glen Canyon Dam Adaptive Management Program (GCDAMP), a Federal initiative authorized to ensure

2008 High-Flow Experiment at Glen Canyon Dam Benefits Colorado River Resources in Grand Canyon National Park

USGS Publications Warehouse

Melis, Theodore S.; Topping, David J.; Grams, Paul E.; Rubin, David M.; Wright, Scott A.; Draut, Amy E.; Hazel, Joseph E.; Ralston, Barbara E.; Kennedy, Theodore A.; Rosi-Marshall, Emma; Korman, Josh; Hilwig, Kara D.; Schmit, Lara M.

2010-01-01

On March 5, 2008, the Department of the Interior began a 60-hour high-flow experiment at Glen Canyon Dam, Arizona, to determine if water releases designed to mimic natural seasonal flooding could be used to improve downstream resources in Glen Canyon National Recreation Area and Grand Canyon National Park. U.S. Geological Survey (USGS) scientists and their cooperators undertook a wide range of physical and biological resource monitoring and research activities before, during, and after the release. Scientists sought to determine whether or not high flows could be used to rebuild Grand Canyon sandbars, create nearshore habitat for the endangered humpback chub, and benefit other resources such as archaeological sites, rainbow trout, aquatic food availability, and riverside vegetation. This fact sheet summarizes research completed by January 2010.

Reconstructing western Grand Canyon's lava dams and their failure mechanisms: new insights from geochemical correlation and 40Ar/39Ar dating

NASA Astrophysics Data System (ADS)

Crow, R.; Karlstrom, K. E.; McIntosh, W. C.; Peters, L.; Dunbar, N. W.

2010-12-01

New geochemical analyzes and 40Ar/39Ar dating of lava dam remnants allows for the more accurate reconstruction of the timing, extent, and structure of western Grand Canyon’s lava dams. Whole-rock major, trace, and rare-earth element (REE) analyzes on over 60 basaltic lava dam remnants, cascades, plugs, and basaltic alluvium, show compositional variation from basanites to alkali basalts to tholeiites. Whitmore Canyon flows, for example, are some of the only tholeiitic flows and have a distinguishable trace and REE composition, which allows for correlation of dam remnants. Over 30 new high-precision 40Ar/39Ar dates also aid in remnant correlation and establish a better-constrained sequence of intra-canyon lava dams. Reliable 40Ar/39Ar dates on western Grand Canyon’s intra-canyon basalts range from ca. 100 ka to 840 ka (new date). The best understood lava dam formed from tholeiitic flows that erupted on the north rim, flowed down Whitmore side canyon and blocked a 6-km-long reach of the Grand Canyon. The youngest of these flows is unique because we know its age (200ka), its composition (tholeiitic), and the exact area where it entered Grand Canyon. The highest flow in the resulting dam, Whitmore Cascade, is capped with very coarse basaltic alluvium that previous workers have attributed to an upstream catastrophic dam failure event at about 200 ka. However, strong similarities between the geochemistry and age of the alluvium with the underlying Whitmore Cascade flow suggest that the alluvial deposit is related to failure of the 200 ka Whitmore Cascade dam itself. Similarly the 100 ka Upper Gray Ledge flow is commonly overlain by a balsaltic alluvium that is indistinguishable in terms of age and geochemistry from the underlying Upper Gray Ledge flow. These observations lead to a new model for Grand Canyon lava dams by which lava dams undergo multi-staged failure where the upstream parts of dams fail quickly (sometimes catastrophically) but downstream parts are

Sharing Perspectives and Learning from One Another: Southern Paiutes, Scientists, and Policymakers in the Glen Canyon Dam Adaptive Management Program

NASA Astrophysics Data System (ADS)

Austin, D. E.; Bulletts, K.; Bulletts, C.

2017-12-01

The traditional lands of the Southern Paiute people in the United States are bounded by more than 600 miles of the Colorado River from the Kaiparowits Plateau in the north to Blythe, California in the south. According to Southern Paiute traditional knowledge, Southern Paiutes were the first inhabitants of this region and are responsible for protecting and managing this land along with the water and all that is upon and within it. In 1963, the Bureau of Reclamation completed construction of Glen Canyon Dam on the Colorado River, and in 1972, the Glen Canyon National Recreation Area was established, encompassing Lake Mead above the Dam and a world class trout fishery on the Colorado River between the Dam and Lees Ferry. Below Lees Ferry on its way to Lake Mead and Hoover Dam, the Colorado River flows through Grand Canyon National Park and the Navajo and Hualapai reservations. U.S. federal law requires that Glen Canyon Dam be operated with minimal impact to the natural, recreational, and cultural resources of the region of the Colorado River that is potentially impacted by flows from the Dam. The Grand Canyon Protection Act and the Environmental Impact Statement (EIS) for the Operation of the Glen Canyon Dam established a program of long-term research and monitoring of the effects of the Dam on these resources. In 1991, three Southern Paiute tribes - the Kaibab Band of Paiute Indians, the Paiute Indian Tribe of Utah, and the San Juan Southern Paiute Tribe - agreed to participate in studies to identify cultural resources impacted by Glen Canyon Dam and to recommend strategies for their protection, In 1995, the EIS was completed and transition to the Adaptive Management Program (AMP) called for in the Grand Canyon Protection Act was begun. At that time, Southern Paiute activities expanded to include assessing potential environmental and cultural impacts of the dam, developing monitoring procedures, and interacting with scientists, other tribal representatives, and

Geomorphic Change Detection and Quantification Using LiDAR, SONAR and RTK-GPS of Sandbars along the Snake River in Hells Canyon

NASA Astrophysics Data System (ADS)

Morehead, M. D.; Wilson, T.; Butler, M.; Seal, N.

2012-12-01

Sediment depletion downstream of large dams causes long-term geomorphic change along a river reach. Short- and long-term, natural and human-altered discharge patterns cause additional geomorphic change. Annual high-resolution, topobathymetry data are being collected on sandbars to track patterns of geomorphic and volumetric change through time. The sandbars are located along the Hells Canyon reach of the Snake River on the Oregon/Idaho border. The bars are downstream of a number of dams that have cut off the upstream source of sand to the Hells Canyon reach. We are combining LiDAR data for above water areas, multibeam SONAR data for below water areas and RTK-GPS data for the water/land interface and densely vegetated areas. Idaho Power has installed and surveyed a control point network to allow accurate positioning of the data and aligning of the various data sets. Data densities are a few points per square meter with the RTK-GPS, tens of points per square meter with the SONAR, and up to hundreds of points per square meter with the ground-based LiDAR. Automated and manual methods are being used to clean the point cloud data. A number of techniques are being used to convert the point clouds to grids, typically utilizing a unique technique for each data type (GPS, LiDAR, and SONAR). Surface roughness data are being used to determine the edges of the sand region, especially in the underwater area where we do not have visual confirmation of the boundary. After the different data types are gridded, they are combined to create seamless surfaces which are then analyzed. The morphologies of the central crest and the back channel of the sandbars are changing between years. In years with higher than average spring flows, the central crest of the sandbars increases in elevation and the back channels deepen. In years with moderate and low spring flows, the height of the crests decline and the back channels fill in. The flattening of the sandbars is attributed to natural

Influence of a dam on fine-sediment storage in a canyon river

USGS Publications Warehouse

Hazel, J.E.; Topping, D.J.; Schmidt, J.C.; Kaplinski, M.

2006-01-01

Glen Canyon Dam has caused a fundamental change in the distribution of fine sediment storage in the 99-km reach of the Colorado River in Marble Canyon, Grand Canyon National Park, Arizona. The two major storage sites for fine sediment (i.e., sand and finer material) in this canyon river are lateral recirculation eddies and the main-channel bed. We use a combination of methods, including direct measurement of sediment storage change, measurements of sediment flux, and comparison of the grain size of sediment found in different storage sites relative to the supply and that in transport, in order to evaluate the change in both the volume and location of sediment storage. The analysis shows that the bed of the main channel was an important storage environment for fine sediment in the predam era. In years of large seasonal accumulation, approximately 50% of the fine sediment supplied to the reach from upstream sources was stored on the main-channel bed. In contrast, sediment budgets constructed for two short-duration, high experimental releases from Glen Canyon Dam indicate that approximately 90% of the sediment discharge from the reach during each release was derived from eddy storage, rather than from sandy deposits on the main-channel bed. These results indicate that the majority of the fine sediment in Marble Canyon is now stored in eddies, even though they occupy a small percentage (???17%) of the total river area. Because of a 95% reduction in the supply of fine sediment to Marble Canyon, future high releases without significant input of tributary sediment will potentially erode sediment from long-term eddy storage, resulting in continued degradation in Marble Canyon. Copyright 2006 by the American Geophysical Union.

Historical physical and chemical data for water in Lake Powell and from Glen Canyon Dam releases, Utah-Arizona, 1964–2012

USGS Publications Warehouse

Vernieu, William S.

2013-01-01

This report presents the physical and chemical characteristics of water in Lake Powell and from Glen Canyon Dam releases from 1964 through 2012. These data are available in a several electronic formats. Data have been collected throughout this period by various offices of the Bureau of Reclamation and U.S. Geological Survey and are compiled to represent the existing body of chemical and physical information on Lake Powell and Glen Canyon Dam releases. From this record, further interpretation may be made concerning mixing processes in Lake Powell, the movement and fate of advective inflow currents, effects of climate and hydrological variations, and the effects of the operation and structure of Glen Canyon Dam on the quality of water in Lake Powell and from Glen Canyon Dam releases.

77 FR 43117 - Glen Canyon Dam Adaptive Management Work Group

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-23

... [email protected] . SUPPLEMENTARY INFORMATION: The Glen Canyon Dam Adaptive Management Program (AMP) was...-575) of 1992. The AMP includes a Federal advisory committee, the AMWG, a technical work group (TWG), a... the AMP. To view a copy of the agenda and documents related to the above meeting, please visit...

77 FR 9265 - Glen Canyon Dam Adaptive Management Work Group

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-16

... (AMP) was implemented as a result of the Record of Decision on the Operation of Glen Canyon Dam Final.... L. 102-575) of 1992. The AMP includes a Federal advisory committee, the AMWG, a technical work group... administrative and resource issues pertaining to the AMP. To view a copy of the agenda and documents related to...

Turbid releases from Glen Canyon Dam, Arizona, following rainfall-runoff events of September 2013

USGS Publications Warehouse

Wildman, Richard A.; Vernieu, William

2017-01-01

Glen Canyon Dam is a large dam on the Colorado River in Arizona. In September 2013, it released turbid water following intense thunderstorms in the surrounding area. Turbidity was >15 nephelometric turbidity units (NTU) for multiple days and >30 NTU at its peak. These unprecedented turbid releases impaired downstream fishing activity and motivated a rapid-response field excursion. At 5 locations upstream from the dam, temperature, specific conductance, dissolved oxygen, chlorophyll a, and turbidity were measured in vertical profiles. Local streamflow and rainfall records were retrieved, and turbidity and specific conductance data in dam releases were evaluated. Profiling was conducted to determine possible sources of turbidity from 3 tributaries nearest the dam, Navajo, Antelope, and Wahweap creeks, which entered Lake Powell as interflows during this study. We discuss 4 key conditions that must have been met for tributaries to influence turbidity of dam releases: tributary flows must have reached the dam, tributary flows must have been laden with sediment, inflow currents must have been near the depth of dam withdrawals, and the settling velocity of particles must have been slow. We isolate 2 key uncertainties that reservoir managers should resolve in future similar studies: the reach of tributary water into the reservoir thalweg and the distribution of particle size of suspended sediment. These uncertainties leave the source of the turbidity ambiguous, although an important role for Wahweap Creek is possible. The unique combination of limnological factors we describe implies that turbid releases at Glen Canyon Dam will continue to be rare.

75 FR 20381 - Glen Canyon Dam Adaptive Management Work Group (AMWG)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-19

... call). SUMMARY: The Glen Canyon Dam Adaptive Management Program (AMP) was implemented as a result of... AMP includes a Federal advisory committee (AMWG), a technical work group (TWG), a monitoring and... visit Reclamation's Web site at: http://www.usbr.gov/uc/rm/amp/amwg/mtgs/10may06CC/index.html...

The effects of Glen Canyon Dam operations on early life stages of rainbow trout in the Colorado River

USGS Publications Warehouse

Korman, Josh; Melis, Theodore S.

2011-01-01

The Lees Ferry reach of the Colorado River-a 16-mile segment from Glen Canyon Dam to the confluence with the Paria River-supports an important recreational rainbow trout (Oncorhynchus mykiss) fishery. In Grand Canyon, nonnative rainbow trout prey on and compete for habitat and food with native fish, such as the endangered humpback chub (Gila cypha). Experimental flow fluctuations from the dam during winter and spring 2003-5 dewatered and killed a high proportion of rainbow trout eggs in gravel spawning bars, but this mortality had no measurable effect on the abundance of juvenile fish. Flow fluctuations during summer months reduced growth of juvenile trout relative to steadier flows. A high-flow experiment in March 2008 increased both trout survival rates for early life stages and fish abundance. These findings demonstrate that Glen Canyon Dam operations directly affect the trout population in the Lees Ferry reach and could be used to regulate nonnative fish abundance to limit potential negative effects of trout on native fish in Grand Canyon.

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

78 FR 42799 - Glen Canyon Dam Adaptive Management Work Group Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-17

... Environmental Impact Statement, (2) results of the 2012 Fall high flow experiment, (3) basin hydrology and the potential for a fall high flow experiment, (4) reports from the Glen Canyon Dam Tribal Liaison. The AMWG... Office, 125 South State Street, Room 6107, Salt Lake City, Utah, 84138; telephone 801-524-3781; facsimile...

76 FR 54487 - Charter Renewal, Glen Canyon Dam Adaptive Management Work Group

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-01

... Management Work Group AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of renewal. SUMMARY: Following... Interior (Secretary) is renewing the charter for the Glen Canyon Dam Adaptive Management Work Group. The purpose of the Adaptive Management Work Group is to advise and to provide recommendations to the Secretary...

USGS Workshop on Scientific Aspects of a Long-Term Experimental Plan for Glen Canyon Dam, April 10-11, 2007, Flagstaff, Arizona

USGS Publications Warehouse

,

2008-01-01

Executive Summary Glen Canyon Dam is located in the lower reaches of Glen Canyon National Recreation Area on the Colorado River, approximately 15 miles upriver from Grand Canyon National Park (fig. 1). In 1992, Congress passed and the President signed into law the Grand Canyon Protection Act (GCPA; title XVIII, sec. 1801?1809, of Public Law 102-575), which seeks ?to protect, mitigate adverse impacts to, and improve the values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established.? The Glen Canyon Dam Adaptive Management Program (GCDAMP) was implemented as a result of the 1996 Record of Decision on the Operation of Glen Canyon Dam Final Environmental Impact Statement to ensure that the primary mandate of the GCPA is met through advances in information and resources management (U.S. Department of the Interior, 1995). On November 3, 2006, the Bureau of Reclamation (Reclamation) announced it would develop a long-term experimental plan environmental impact statement (LTEP EIS) for operational activities at Glen Canyon Dam and other management actions on the Colorado River. The purpose of the long-term experimental plan is twofold: (1) to increase the scientific understanding of the ecosystem and (2) to improve and protect important downstream resources. The proposed plan would implement a structured, longterm program of experimentation to include dam operations, potential modifications to Glen Canyon Dam intake structures, and other management actions such as removal of nonnative fish species. The development of the long-term experimental plan continues efforts begun by the GCDAMP to protect resources downstream of Glen Canyon Dam, including Grand Canyon, through adaptive management and scientific experimentation. The LTEP EIS will rely on the extensive scientific studies that have been undertaken as part of the adaptive management program by the U.S. Geological Survey?s (USGS) Grand Canyon Monitoring and Research Center (GCMRC

76 FR 47237 - Notice of Public Meeting for the Glen Canyon Dam Adaptive Management Work Group Federal Advisory...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-04

... . SUPPLEMENTARY INFORMATION: The Glen Canyon Dam Adaptive Management Program (AMP) was implemented as a result of... AMP includes a Federal advisory committee, the AMWG, a technical work group (TWG), a Grand Canyon... other administrative and resource issues pertaining to the AMP. To view a copy of the agenda and...

Anthropogenic Impacts of Recreational Use on Sandbars in Hells Canyon on the Snake River, Idaho

NASA Astrophysics Data System (ADS)

Morehead, M. D.

2014-12-01

Sandbars along large rivers are important cultural, recreational, and natural resources. In modern, historic and prehistoric times the sandbars have been used for camping, hunting, fishing and recreational activities. Sandbars are a dynamic geomorphic unit of the river system that stores and exchanges sand with the main river channel. Both natural and anthropogenic changes to river systems affect the size, shape and dynamics of sandbars. During high spring flows, the Snake River can resupply and build the sand bars. During the lower flows of the summer and fall the sand is redistributed to lower levels by natural and anthropogenic forces, where it can be remobilized by the river and exported from the bar. During the summer and fall high use season many people camp and recreate on the bars and redistribute the sand. This study utilizes change detection from repeat high resolution terrestrial LiDAR scanning surveys to study the impacts humans have on the sandbars in Hells Canyon. Nearly a decade of annual LiDAR and Bathymetric surveys were used to place these recreational impacts into the context of overall sandbar dynamics.

24. VIEW OF CANYON TAKEN FROM NORTH CANYON RIM AROUND ...

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

24. VIEW OF CANYON TAKEN FROM NORTH CANYON RIM AROUND 1920. CAMERA FACES SOUTH. VILLAGE IS TREE-COVERED AREA TO LEFT OF DAM AND POWERHOUSE. SUPERINTENDENT SAM GLASS'S ORCHARD IS DOWNSTREAM OF DAM ABOUT A QUARTER OF A MILE. - Swan Falls Village, Snake River, Kuna, Ada County, ID

Calculated hydrographs for unsteady research flows at selected sites along the Colorado River downstream from Glen Canyon Dam, Arizona, 1990 and 1991

USGS Publications Warehouse

Griffin, Eleanor R.; Wiele, Stephen M.

1996-01-01

A one-dimensional model of unsteady discharge waves was applied to research flowr that were released from Glen Canyon Dam in support of the Glen Canyon Environmental Studies. These research flows extended over periods of 11 days during which the discharge followed specific, regular patterns repeated on a daily cycle that were similar to the daily releases for power generation. The model was used to produce discharge hydrographs at 38 selected sites in Marble and Grand Canyons for each of nine unsteady flows released from the dam in 1990 and 1991. In each case, the discharge computed from stage measurements and the associated stage-discharge relation at the streamflow-gaging station just below the dam (09379910 Colorado River Hlow Glen Canyon Dam) was routed to Diamond Creek, which is 386 kilometers downstream. Steady and unsteady tributary inflows downstream from the dam were included in the model calculations. Steady inflow to the river from tributaries downstream from the dam was determined for each case by comparing the steady base flow preceding and following the unsteady flow measured at six streamflow-gaging stations between Glen Canyon Dam and Diamond Creek. During three flow periods, significant unsteady inflow was received from the Paria River, or the Little Colorado River, or both. The amount and timing of unsteady inflow was determined using the discharge computed from records of streamflow-gaging stations on the tributaries. Unsteady flow then was added to the flow calculated by the model at the appropriate location. Hydrographs were calculated using the model at 5 streamflow-gaging stations downstream from the dam and at 33 beach study sites. Accuracy of model results was evaluated by comparing the results to discharge hydrographs computed from the records of the five streamflow-gaging stations between Lees Ferry and Lake Mead. Results show that model predictions of wave speed and shape agree well with data from the five streamflow-gaging stations.

Research Furthers Conservation of Grand Canyon Sandbars

USGS Publications Warehouse

Melis, Theodore S.; Topping, David J.; Rubin, David M.; Wright, Scott A.

2007-01-01

Grand Canyon National Park lies approximately 25 km (15 mi) down-river from Glen Canyon Dam, which was built on the Colorado River just south of the Arizona-Utah border in Glen Canyon National Recreation Area. Before the dam began to regulate the Colorado River in 1963, the river carried such large quantities of red sediment, for which the Southwest is famous, that the Spanish named the river the Rio Colorado, or 'red river'. Today, the Colorado River usually runs clear below Glen Canyon Dam because the dam nearly eliminates the main-channel sand supply. The daily and seasonal flows of the river were also altered by the dam. These changes have disrupted the sedimentary processes that create and maintain Grand Canyon sandbars. Throughout Grand Canyon, sandbars create habitat for native plants and animals, supply camping beaches for river runners and hikers, and provide sediment needed to protect archaeological resources from weathering and erosion. Maintenance of sandbars in the Colorado River ecosystem, the river corridor that stretches from the dam to the western boundary of Grand Canyon National Park, is a goal of the Glen Canyon Dam Adaptive Management Program. The program is a federally authorized initiative to ensure that the mandates of the Grand Canyon Protection Act of 1992 are met through advances in information and resource management. The U.S. Geological Survey's Grand Canyon Monitoring and Research Center has responsibility for scientific monitoring and research efforts for the program. Extensive research and monitoring during the past decade have resulted in the identification of possible alternatives for operating Glen Canyon Dam that hold new potential for the conservation of sand resources.

Grand Canyon Monitoring and Research Center

USGS Publications Warehouse

Hamill, John F.

2009-01-01

The Grand Canyon of the Colorado River, one of the world's most spectacular gorges, is a premier U.S. National Park and a World Heritage Site. The canyon supports a diverse array of distinctive plants and animals and contains cultural resources significant to the region's Native Americans. About 15 miles upstream of Grand Canyon National Park sits Glen Canyon Dam, completed in 1963, which created Lake Powell. The dam provides hydroelectric power for 200 wholesale customers in six western States, but it has also altered the Colorado River's flow, temperature, and sediment-carrying capacity. Over time this has resulted in beach erosion, invasion and expansion of nonnative species, and losses of native fish. Public concern about the effects of Glen Canyon Dam operations prompted the passage of the Grand Canyon Protection Act of 1992, which directs the Secretary of the Interior to operate the dam 'to protect, mitigate adverse impacts to, and improve values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established...' This legislation also required the creation of a long-term monitoring and research program to provide information that could inform decisions related to dam operations and protection of downstream resources.

Colorado River sediment transport: 1. Natural sediment supply limitation and the influence of Glen Canyon Dam

USGS Publications Warehouse

Topping, David J.; Rubin, David M.; Vierra, L.E.

2000-01-01

Analyses of flow, sediment‐transport, bed‐topographic, and sedimentologic data suggest that before the closure of Glen Canyon Dam in 1963, the Colorado River in Marble and Grand Canyons was annually supply‐limited with respect to fine sediment (i.e., sand and finer material). Furthermore, these analyses suggest that the predam river in Glen Canyon was not supply‐limited to the same degree and that the degree of annual supply limitation increased near the head of Marble Canyon. The predam Colorado River in Grand Canyon displays evidence of four effects of supply limitation: (1) seasonal hysteresis in sediment concentration, (2) seasonal hysteresis in sediment grain size coupled to the seasonal hysteresis in sediment concentration, (3) production of inversely graded flood deposits, and (4∥ development or modification of a lag between the time of a flood peak and the time of either maximum or minimum (depending on reach geometry) bed elevation. Analyses of sediment budgets provide additional support for the interpretation that the predam river was annually supply‐limited with respect to fine sediment, but it was not supply‐limited with respect to fine sediment during all seasons. In the average predam year, sand would accumulate and be stored in Marble Canyon and upper Grand Canyon for 9 months of the year (from July through March) when flows were dominantly below 200–300 m3/s; this stored sand was then eroded during April through June when flows were typically higher. After closure of Glen Canyon Dam, because of the large magnitudes of the uncertainties in the sediment budget, no season of substantial sand accumulation is evident. Because most flows in the postdam river exceed 200–300 m3/s, substantial sand accumulation in the postdam river is unlikely.

White Sturgeon Management Plan in the Snake River between Lower Granite and Hells Canyon Dams; Nez Perce Tribe, 1997-2005 Final Report.

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

Nez Perce Tribe Resources Management Staff,

White sturgeon in the Hells Canyon reach (HCR) of the Snake River are of cultural importance to the Nez Perce Tribe. However, subsistence and ceremonial fishing opportunities have been severely limited as a result of low numbers of white sturgeon in the HCR. Hydrosystem development in the Columbia River Basin has depressed numbers and productivity of white sturgeon in the HCR by isolating fish in impounded reaches of the basin, restricting access to optimal rearing habitats, reducing the anadromous forage base, and modifying early life-history habitats. Consequently, a proactive management plan is needed to mitigate for the loss of whitemore » sturgeon production in the HCR, and to identify and implement feasible measures that will restore and rebuild the white sturgeon population to a level that sustains viability and can support an annual harvest. This comprehensive and adaptive management plan describes the goals, objectives, strategies, actions, and expected evaluative timeframes for restoring the white sturgeon population in the HCR. The goal of this plan, which is to maintain a viable, persistent population that can support a sustainable fishery, is supported by the following objectives: (1) a natural, stable age structure comprising both juveniles and a broad spectrum of spawning age-classes; (2) stable or increasing numbers of both juveniles and adults; (3) consistent levels of average recruitment to ensure future contribution to reproductive potential; (4) stable genetic diversity comparable to current levels; (5) a minimum level of abundance of 2,500 adults to minimize extinction risk; and (6) provision of an annual sustainable harvest of 5 kg/ha. To achieve management objectives, potential mitigative actions were developed by a Biological Risk Assessment Team (BRAT). Identified strategies and actions included enhancing growth and survival rates by restoring anadromous fish runs and increasing passage opportunities for white sturgeon, reducing mortality

The rate and pattern of bed incision and bank adjustment on the Colorado River in Glen Canyon downstream from Glen Canyon Dam, 1956-2000

USGS Publications Warehouse

Grams, P.E.; Schmidt, J.C.; Topping, D.J.

2007-01-01

Closure of Glen Canyon Dam in 1963 transformed the Colorado River by reducing the magnitude and duration of spring floods, increasing the magnitude of base flows, and trapping fine sediment delivered from the upper watershed. These changes caused the channel downstream in Glen Canyon to incise, armor, and narrow. This study synthesizes over 45 yr of channel-change measurements and demonstrates that the rate and style of channel adjustment are directly related to both natural processes associated with sediment deficit and human decisions about dam operations. Although bed lowering in lower Glen Canyon began when the first cofferdam was installed in 1959, most incision occurred in 1965 in conjunction with 14 pulsed high flows that scoured an average of 2.6 m of sediment from the center of the channel. The average grain size of bed material has increased from 0.25 mm in 1956 to over 20 mm in 1999. The magnitude of incision at riffles decreases with distance downstream from the dam, while the magnitude of sediment evacuation from pools is spatially variable and extends farther downstream. Analysis of bed-material mobility indicates that the increase in bed-material grain size and reduction in reach-average gradient are consistent with the transformation of an adjustable-bed alluvial river to a channel with a stable bed that is rarely mobilized. Decreased magnitude of peak discharges in the post-dam regime coupled with channel incision and the associated downward shifts of stage-discharge relations have caused sandbar and terrace erosion and the transformation of previously active sandbars and gravel bars to abandoned deposits that are no longer inundated. Erosion has been concentrated in a few pre-dam terraces that eroded rapidly for brief periods and have since stabilized. The abundance of abandoned deposits decreases downstream in conjunction with decreasing magnitude of shift in the stage-discharge relations. In the downstream part of the study area where riffles

The Glen Canyon Dam Adaptive Management Program: An experiment in science-based resource management

NASA Astrophysics Data System (ADS)

kaplinski, m

2001-12-01

In 1996, Glen Canyon Dam Adaptive Management (GCDAMP) program was established to provide input on Glen Canyon Dam operations and their affect on the Colorado Ecosystem in Grand Canyon. The GCDAMP is a bold experiment in federal resource management that features a governing partnership with all relevant stakeholders sitting at the same table. It is a complicated, difficult process where stakeholder-derived management actions must balance resource protection with water and power delivery compacts, the Endangered Species Act, the National Historical Preservation Act, the Grand Canyon Protection Act, National Park Service Policy, and other stakeholder concerns. The program consists of four entities: the Adaptive Management Workgroup (AMWG), the Technical Workgroup (TWG), the Grand Canyon Monitoring and Research Center (GCMRC), and independent review panels. The AMWG and TWG are federal advisory committees that consists of federal and state resource managers, Native American tribes, power, environmental and recreation interests. The AMWG is develops, evaluates and recommends alternative dam operations to the Secretary. The TWG translates AMWG policy and goals into management objectives and information needs, provides questions that serve as the basis for long-term monitoring and research activities, interprets research results from the GCMRC, and prepares reports as required for the AMWG. The GCMRC is an independent science center that is responsible for all GCDAMP monitoring and research activities. The GCMRC utilizes proposal requests with external peer review and an in-house staff that directs and synthesizes monitoring and research results. The GCMRC meets regularly with the TWG and AMWG and provides scientific information on the consequences of GCDAMP actions. Independent review panels consist of external peer review panels that provide reviews of scientific activities and the program in general, technical advice to the GCMRC, TWG and AMWG, and play a critical

Scientific monitoring plan in support of the selected alternative of the Glen Canyon Dam Long-Term Experimental and Management Plan

USGS Publications Warehouse

Vanderkooi, Scott P.; Kennedy, Theodore A.; Topping, David J.; Grams, Paul E.; Ward, David L.; Fairley, Helen C.; Bair, Lucas S.; Sankey, Joel B.; Yackulic, Charles B.; Schmidt, John C.

2017-01-18

IntroductionThe purpose of this document is to describe a strategy by which monitoring and research data in the natural and social sciences will be collected, analyzed, and provided to the U.S. Department of the Interior (DOI), its bureaus, and to the Glen Canyon Dam Adaptive Management Program (GCDAMP) in support of implementation of the Glen Canyon Dam Long-Term Experimental and Management Plan (LTEMP) (U.S. Department of the Interior, 2016a). The selected alternative identified in the LTEMP Record of Decision (ROD) (U.S. Department of the Interior, 2016b) describes various data collection, analysis, modeling, and interpretation efforts to be conducted by the U.S. Geological Survey’s (USGS) Grand Canyon Monitoring and Research Center (GCMRC), partner agencies, and cooperators that will inform decisions about operations of Glen Canyon Dam and management of downstream resources between 2017 and 2037, the performance period of the LTEMP. General data collection, analysis, modeling, and interpretation activities are described in this science plan, whereas specific monitoring and research activities and detailed study plans are to be described in the GCDAMP’s triennial work plans (TWPs) to be developed by the Bureau of Reclamation and GCMRC with input from partner agencies and cooperators during the LTEMP period, which are to be reviewed and recommended by the GCDAMP and approved by the Secretary of the Interior. The GCDAMP consists of several components, the primary committee being the Adaptive Management Work Group (AMWG). This Federal advisory committee is composed of 25 agencies and stakeholder groups and is chaired by the Secretary of the Interior’s designee. The AMWG makes recommendations to the Secretary of the Interior concerning operations of Glen Canyon Dam and other experimental management actions that are intended to fulfill some obligations of the Grand Canyon Protection Act of 1992. The Technical Work Group (TWG) is a subcommittee of the AMWG and

Effects of a test flood on fishes of the Colorado River in Grand Canyon, Arizona

USGS Publications Warehouse

Valdez, R.A.; Hoffnagle, T.L.; McIvor, C.C.; McKinney, T.; Leibfried, W.C.

2001-01-01

A beach/habitat-building flow (i.e., test flood) of 1274 m3/s, released from Glen Canyon Dam down the Colorado River through Grand Canyon, had little effect on distribution, abundance, or movement of native fishes, and only short-term effects on densities of some nonnative species Shoreline and backwater catch rates of native fishes, including juvenile humpback chub (Gila cypha), flannelmouth suckers (Catostomus latipinnis), and bluehead suckers (C. discobolus), and all ages of speckled dace (Rhinichthys osculus), were not significantly different before and after the flood. Annual spring spawning migrations of flannelmouth suckers into the Paria River and endangered humpback chub into the Little Colorado River (LCR) took place during and after the flood, indicating no impediment to fish migrations. Pre-spawning adults staged in large slack water pools formed at the mouths of these tributaries during the flood. Net movement and habitat used by nine radio-tagged adult humpback chub during the flood were not significantly different from prior observations. Diet composition of adult humpback chub varied, but total biomass did not differ significantly before, during, and after the flood, indicating opportunistic feeding for a larger array of available food items displaced by the flood. Numbers of nonnative rainbow trout (Oncorhynchus mykiss) <152 mm total length decreased by ???8% in electrofishing samples from the dam tailwaters (0-25 km downstream of the dam) during the flood. Increased catch rates in the vicinity of the LCR (125 km downstream of the dam) and Hell's Hollow (314 km downstream of the dam) suggest that these young trout were displaced downstream by the flood, although displacement distance was unknown since some fish could have originated from local populations associated with intervening tributaries. Abundance, catch rate, body condition, and diet of adult rainbow trout in the dam tailwaters were not significantly affected by the flood, and the flood

Abiotic & biotic responses of the Colorado River to controlled floods at Glen Canyon Dam, Arizona, USA

USGS Publications Warehouse

Korman, Josh; Melis, Ted; Kennedy, Theodore A.

2012-01-01

Closure of Glen Canyon Dam reduced sand supply to the Colorado River in Grand Canyon National Park by about 94% while its operation has also eroded the park's sandbar habitats. Three controlled floods released from the dam since 1995 suggest that sandbars might be rebuilt and maintained, but only if repeated floods are timed to follow tributary sand deliveries below the dam. Monitoring data show that sandbars are dynamic and that their erosion after bar building is positively related with mean daily discharge and negatively related with tributary sand production after controlled floods. The March 2008 flood affected non-native rainbow trout abundance in the Lees Ferry tailwater, which supports a blue ribbon fishery. Downstream trout dispersal from the tailwater results in negative competitive interactions and predation on endangered humpback chub. Early survival rates of age-0 trout increased more than fourfold following the 2008 flood, and twofold in 2009, relative to prior years (2006-2007). Hatch-date analysis indicated that early survival rates were much higher for cohorts that emerged about 2 months after the 2008 flood relative to cohorts that emerged earlier that year. The 2009 survival data suggest that tailwater habitat improvements persisted for at least a year, but apparently decreased in 2010. Increased early survival rates for trout coincided with the increased availability of higher quality drifting food items after the 2008 flood owing to an increase in midges and black flies, preferred food items of rainbow trout. Repeated floods from the dam might sustainably rebuild and maintain sandbars if released when new tributary sand is available below the tailwater. Spring flooding might also sustain increased trout abundance and benefit the tailwater fishery, but also be a potential risk to humpback chub in Grand Canyon.

Sediment Transport During Three Controlled-Flood Experiments on the Colorado River Downstream from Glen Canyon Dam, with Implications for Eddy-Sandbar Deposition in Grand Canyon National Park

USGS Publications Warehouse

Topping, David J.; Rubin, David M.; Grams, Paul E.; Griffiths, Ronald E.; Sabol, Thomas A.; Voichick, Nicholas; Tusso, Robert B.; Vanaman, Karen M.; McDonald, Richard R.

2010-01-01

Three large-scale field experiments were conducted on the Colorado River downstream from Glen Canyon Dam in 1996, 2004, and 2008 to evaluate whether artificial (that is, controlled) floods released from the dam could be used in conjunction with the sand supplied by downstream tributaries to rebuild and sustainably maintain eddy sandbars in the river in Grand Canyon National Park. Higher suspended-sand concentrations during a controlled flood will lead to greater eddy-sandbar deposition rates. During each controlled flood experiment, sediment-transport and bed-sediment data were collected to evaluate sediment-supply effects on sandbar deposition. Data collection substantially increased in spatial and temporal density with each subsequent experiment. The suspended- and bed-sediment data collected during all three controlled-flood experiments are presented and analyzed in this report. Analysis of these data indicate that in designing the hydrograph of a controlled flood that is optimized for sandbar deposition in a given reach of the Colorado River, both the magnitude and the grain size of the sand supply must be considered. Because of the opposing physical effects of bed-sand area and bed-sand grain size in regulating suspended-sand concentration, larger amounts of coarser sand on the bed can lead to lower suspended-sand concentrations, and thus lower rates of sandbar deposition, during a controlled flood than can lesser amounts of finer sand on the bed. Although suspended-sand concentrations were higher at all study sites during the 2008 controlled-flood experiment (CFE) than during either the 1996 or 2004 CFEs, these higher concentrations were likely associated with more sand on the bed of the Colorado River in only lower Glen Canyon. More sand was likely present on the bed of the river in Grand Canyon during the 1996 CFE than during either the 2004 or 2008 CFEs. The question still remains as to whether sandbars can be sustained in the Colorado River in Grand

Geochemical discrimination of five pleistocene Lava-Dam outburst-flood deposits, western Grand Canyon, Arizona

USGS Publications Warehouse

Fenton, C.R.; Poreda, R.J.; Nash, B.P.; Webb, R.H.; Cerling, T.E.

2004-01-01

Pleistocene basaltic lava dams and outburst-flood deposits in the western Grand Canyon, Arizona, have been correlated by means of cosmogenic 3He (3Hec) ages and concentrations of SiO2, Na2O, K2O, and rare earth elements. These data indicate that basalt clasts and vitroclasts in a given outburst-flood deposit came from a common source, a lava dam. With these data, it is possible to distinguish individual dam-flood events and improve our understanding of the interrelations of volcanism and river processes. At least five lava dams on the Colorado River failed catastrophically between 100 and 525 ka; subsequent outburst floods emplaced basalt-rich deposits preserved on benches as high as 200 m above the current river and up to 53 km downstream of dam sites. Chemical data also distinguishes individual lava flows that were collectively mapped in the past as large long-lasting dam complexes. These chemical data, in combination with age constraints, increase our ability to correlate lava dams and outburst-flood deposits and increase our understanding of the longevity of lava dams. Bases of correlated lava dams and flood deposits approximate the elevation of the ancestral river during each flood event. Water surface profiles are reconstructed and can be used in future hydraulic models to estimate the magnitude of these large-scale floods.

The State of the Colorado River Ecosystem in Grand Canyon: A Report of the Grand Canyon Monitoring and Research Center 1991-2004

USGS Publications Warehouse

Gloss, Steven P.; Lovich, Jeffrey E.; Melis, Theodore S.

2005-01-01

This report is an important milestone in the effort by the Secretary of the Interior to implement the Grand Canyon Protection Act of 1992 (GCPA; title XVIII, secs. 1801-1809, of Public Law 102-575), the most recent authorizing legislation for Federal efforts to protect resources downstream from Glen Canyon Dam. The chapters that follow are intended to provide decision makers and the American public with relevant scientific information about the status and recent trends of the natural, cultural, and recreational resources of those portions of Grand Canyon National Park and Glen Canyon National Recreation Area affected by Glen Canyon Dam operations. Glen Canyon Dam is one of the last major dams that was built on the Colorado River and is located just south of the Arizona-Utah border in the lower reaches of Glen Canyon National Recreation Area, approximately 15 mi (24 km) upriver from Grand Canyon National Park (fig. 1). The information presented here is a product of the Glen Canyon Dam Adaptive Management Program (GCDAMP), a federally authorized initiative to ensure that the primary mandate of the GCPA is met through advances in information and resource management. The U.S. Geological Survey`s (USGS) Grand Canyon Monitoring and Research Center (GCMRC) has responsibility for the scientific monitoring and research efforts for the program, including the preparation of reports such as this one.

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

Evaluation of Water Year 2011 Glen Canyon Dam Flow Release Scenarios on Downstream Sand Storage along the Colorado River in Arizona

USGS Publications Warehouse

Wright, Scott A.; Grams, Paul E.

2010-01-01

This report describes numerical modeling simulations of sand transport and sand budgets for reaches of the Colorado River below Glen Canyon Dam. Two hypothetical Water Year 2011 annual release volumes were each evaluated with six hypothetical operational scenarios. The six operational scenarios include the current operation, scenarios with modifications to the monthly distribution of releases, and scenarios with modifications to daily flow fluctuations. Uncertainties in model predictions were evaluated by conducting simulations with error estimates for tributary inputs and mainstem transport rates. The modeling results illustrate the dependence of sand transport rates and sand budgets on the annual release volumes as well as the within year operating rules. The six operational scenarios were ranked with respect to the predicted annual sand budgets for Marble Canyon and eastern Grand Canyon reaches. While the actual WY 2011 annual release volume and levels of tributary inputs are unknown, the hypothetical conditions simulated and reported herein provide reasonable comparisons between the operational scenarios, in a relative sense, that may be used by decision makers within the Glen Canyon Dam Adaptive Management Program.

Warm Season Storms, Floods, and Tributary Sand Inputs below Glen Canyon Dam: Investigating Salience to Adaptive Management in the Context of a 10-Year Long Controlled Flooding Experiment in Grand Canyon National Park, AZ, USA

NASA Astrophysics Data System (ADS)

Jain, S.; Melis, T. S.; Topping, D. J.; Pulwarty, R. S.; Eischeid, J.

2013-12-01

The planning and decision processes in the Glen Canyon Dam Adaptive Management Program (GCDAMP) strive to balance numerous, often competing, objectives, such as, water supply, hydropower generation, low flow maintenance, maximizing conservation of downstream tributary sand supply, endangered native fish, and other sociocultural resources of Glen Canyon National Recreation Area and Grand Canyon National Park. In this context, use of monitored and predictive information on the warm season floods (at point-to-regional scales) has been identified as lead-information for a new 10-year long controlled flooding experiment (termed the High-Flow Experiment Protocol) intended to determine management options for rebuilding and maintaining sandbars in Grand Canyon; an adaptive strategy that can potentially facilitate improved planning and dam operations. In this work, we focus on a key concern identified by the GCDAMP, related to the timing and volume of tributary sand input from the Paria and Little Colorado Rivers (located 26 and 124 km below the dam, respectively) into the Colorado River in Grand Canyon National Park. Episodic and intraseasonal variations (with links to equatorial and sub-tropical Pacific sea surface temperature variability) in the southwest hydroclimatology are investigated to understand the magnitude, timing and spatial scales of warm season floods from this relatively small, but prolific sand producing drainage of the semi-arid Colorado Plateau. The coupled variations of the flood-driven sediment input (magnitude and timing) from these two drainages into the Colorado River are also investigated. The physical processes, including diagnosis of storms and moisture sources, are mapped alongside the planning and decision processes for the ongoing experimental flood releases from the Glen Canyon Dam which are aimed at achieving restoration and maintenance of sandbars and instream ecology. The GCDAMP represents one of the most visible and widely recognized

Daily and seasonal variability of pH, dissolved oxygen, temperature, and specific conductance in the Colorado River between the forebay of Glen Canyon, Dam and Lees Ferry, northeastern Arizona, 1998-99

USGS Publications Warehouse

Flynn, Marilyn E.; Hart, Robert J.; Marzolf, G. Richard; Bowser, Carl J.

2001-01-01

The productivity of the trout fishery in the tailwater reach of the Colorado River downstream from Glen Canyon Dam depends on the productivity of lower trophic levels. Photosynthesis and respiration are basic biological processes that control productivity and alter pH and oxygen concentration. During 1998?99, data were collected to aid in the documentation of short- and long-term trends in these basic ecosystem processes in the Glen Canyon reach. Dissolved-oxygen, temperature, and specific-conductance profile data were collected monthly in the forebay of Glen Canyon Dam to document the status of water chemistry in the reservoir. In addition, pH, dissolved-oxygen, temperature, and specific-conductance data were collected at five sites in the Colorado River tailwater of Glen Canyon Dam to document the daily, seasonal, and longitudinal range of variation in water chemistry that could occur annually within the Glen Canyon reach.

Multicriteria decision analysis applied to Glen Canyon Dam

USGS Publications Warehouse

Flug, M.; Seitz, H.L.H.; Scott, J.F.

2000-01-01

Conflicts in water resources exist because river-reservoir systems are managed to optimize traditional benefits (e.g., hydropower and flood control), which are historically quantified in economic terms, whereas natural and environmental resources, including in-stream and riparian resources, are more difficult or impossible to quantify in economic terms. Multicriteria decision analysis provides a quantitative approach to evaluate resources subject to river basin management alternatives. This objective quantification method includes inputs from special interest groups, the general public, and concerned individuals, as well as professionals for each resource considered in a trade-off analysis. Multicriteria decision analysis is applied to resources and flow alternatives presented in the environmental impact statement for Glen Canyon Dam on the Colorado River. A numeric rating and priority-weighting scheme is used to evaluate 29 specific natural resource attributes, grouped into seven main resource objectives, for nine flow alternatives enumerated in the environmental impact statement.

Hydrologic data, Colorado River and major tributaries, Glen Canyon Dam to Diamond Creek, Arizona, water years 1990-95

USGS Publications Warehouse

Rote, John J.; Flynn, Marilyn E.; Bills, D.J.

1997-01-01

The U.S. Geological Survey collected hydrologic data at 12 continuous-record stations along the Colorado River and its major tributaries between Glen Canyon Dam and Diamond Creek. The data were collected from October 1989 through September 1995 as part of the Bureau of Reclamation's Glen Canyon Environmental Studies. The data include daily values for streamflow discharge, suspended-sediment discharge, temperature, specific conductance, pH, and dissolved-oxygen concentrations, and discrete values for physical properties and chemical constituents of water. All data are presented in tabular form.

Peak discharge of a Pleistocene lava-dam outburst flood in Grand Canyon, Arizona, USA

USGS Publications Warehouse

Fenton, C.R.; Webb, R.H.; Cerling, T.E.

2006-01-01

The failure of a lava dam 165,000 yr ago produced the largest known flood on the Colorado River in Grand Canyon. The Hyaloclastite Dam was up to 366 m high, and geochemical evidence linked this structure to outburst-flood deposits that occurred for 32 km downstream. Using the Hyaloclastite outburst-flood deposits as paleostage indicators, we used dam-failure and unsteady flow modeling to estimate a peak discharge and flow hydrograph. Failure of the Hyaloclastite Dam released a maximum 11 ?? 109 m3 of water in 31 h. Peak discharges, estimated from uncertainty in channel geometry, dam height, and hydraulic characteristics, ranged from 2.3 to 5.3 ?? 105 m3 s-1 for the Hyaloclastite outburst flood. This discharge is an order of magnitude greater than the largest known discharge on the Colorado River (1.4 ?? 104 m3 s-1) and the largest peak discharge resulting from failure of a constructed dam in the USA (6.5 ?? 104 m3 s-1). Moreover, the Hyaloclastite outburst flood is the oldest documented Quaternary flood and one of the largest to have occurred in the continental USA. The peak discharge for this flood ranks in the top 30 floods (>105 m3 s-1) known worldwide and in the top ten largest floods in North America. ?? 2005 University of Washington. All rights reserved.

Peak discharge of a Pleistocene lava-dam outburst flood in Grand Canyon, Arizona, USA

NASA Astrophysics Data System (ADS)

Fenton, Cassandra R.; Webb, Robert H.; Cerling, Thure E.

2006-03-01

The failure of a lava dam 165,000 yr ago produced the largest known flood on the Colorado River in Grand Canyon. The Hyaloclastite Dam was up to 366 m high, and geochemical evidence linked this structure to outburst-flood deposits that occurred for 32 km downstream. Using the Hyaloclastite outburst-flood deposits as paleostage indicators, we used dam-failure and unsteady flow modeling to estimate a peak discharge and flow hydrograph. Failure of the Hyaloclastite Dam released a maximum 11 × 10 9 m 3 of water in 31 h. Peak discharges, estimated from uncertainty in channel geometry, dam height, and hydraulic characteristics, ranged from 2.3 to 5.3 × 10 5 m 3 s -1 for the Hyaloclastite outburst flood. This discharge is an order of magnitude greater than the largest known discharge on the Colorado River (1.4 × 10 4 m 3 s -1) and the largest peak discharge resulting from failure of a constructed dam in the USA (6.5 × 10 4 m 3 s -1). Moreover, the Hyaloclastite outburst flood is the oldest documented Quaternary flood and one of the largest to have occurred in the continental USA. The peak discharge for this flood ranks in the top 30 floods (>10 5 m 3 s -1) known worldwide and in the top ten largest floods in North America.

Observations of environmental change in Grand Canyon, Arizona

USGS Publications Warehouse

Webb, Robert H.; Melis, Theodore S.; Valdez, Richard A.

2002-01-01

Few scientific data have been collected on pre-dam conditions of the Colorado River corridor through Grand Canyon National Park. Using historical diaries, interviews with pre-dam river runners (referred to as the ?Old Timers?), and historical scientific data and observations, we compiled anecdotal information on environmental change in Grand Canyon. The most significant changes are the: lowering of water temperature in the river, near-elimination of heavily sediment-laden flows, erosion of sand bars, invasion of non-native tamarisk trees, reduction in driftwood, development of marshes, increase in non-native fish at the expense of native fishes, and increase in water bird populations. In addition, few debris flows were observed before closure of Glen Canyon Dam, which might suggests that the frequency of debris flows in Grand Canyon has increased. Other possible changes include decreases in bat populations and increases in swallow and bighorn sheep populations, although the evidence is anecdotal and inconclusive. These results provide a perspective on managing the Colorado River that may allow differentiation of the effects of Glen Canyon Dam from other processes of change.

77 FR 48151 - Boulder Canyon Project

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-13

... DEPARTMENT OF ENERGY Western Area Power Administration Boulder Canyon Project AGENCY: Western Area... Canyon Project (BCP) electric service provided by the Western Area Power Administration (Western). The... INFORMATION: Hoover Dam, authorized by the Boulder Canyon Project Act (45 Stat. 1057, December 21, 1928), sits...

50 CFR 226.205 - Critical habitat for Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River...

Code of Federal Regulations, 2012 CFR

2012-10-01

... salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook salmon. 226.205 Section... Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook... River salmon (except reaches above impassable natural falls, and Dworshak and Hells Canyon Dams...

50 CFR 226.205 - Critical habitat for Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River...

Code of Federal Regulations, 2013 CFR

2013-10-01

... salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook salmon. 226.205 Section... Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook... River salmon (except reaches above impassable natural falls, and Dworshak and Hells Canyon Dams...

50 CFR 226.205 - Critical habitat for Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River...

Code of Federal Regulations, 2014 CFR

2014-10-01

... salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook salmon. 226.205 Section... Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook... River salmon (except reaches above impassable natural falls, and Dworshak and Hells Canyon Dams...

2008 High-Flow Experiment at Glen Canyon Dam-Morphologic Response of Eddy-Deposited Sandbars and Associated Aquatic Backwater Habitats along the Colorado River in Grand Canyon National Park

USGS Publications Warehouse

Grams, Paul E.; Schmidt, John C.; Andersen, Matthew E.

2010-01-01

The March 2008 high-flow experiment (HFE) at Glen Canyon Dam resulted in sandbar deposition and sandbar reshaping such that the area and volume of associated backwater aquatic habitat in Grand Canyon National Park was greater following the HFE. Analysis of backwater habitat area and volume for 116 locations at 86 study sites, comparing one month before and one month after the HFE, shows that total habitat area increased by 30 percent to as much as a factor of 3 and that volume increased by 80 percent to as much as a factor of 15. These changes resulted from an increase in the area and elevation of sandbars, which isolate backwaters from the main channel, and the scour of eddy return-current channels along the bank where the habitat occurs. Because of this greater relief on the sandbars, backwaters were present across a broader range of flows following the HFE than before the experiment. Reworking of sandbars during diurnal fluctuating flow operations in the first 6 months following the HFE caused sandbar erosion and a reduction of backwater size and abundance to conditions that were 5 to 14 percent greater than existed before the HFE. In the months following the HFE, erosion of sandbars and deposition in eddy return-current channels caused reductions of backwater area and volume. However, sandbar relief was still greater in October 2008 such that backwaters were present across a broader range of discharges than in February 2008. Topographic analyses of the sandbar and backwater morphologic data collected in this study demonstrate that steady flows are associated with a greater amount of continuously available backwater habitat than fluctuating flows, which result in a greater amount of intermittently available habitat. With the exception of the period immediately following the HFE, backwater habitat in 2008 was greater for steady flows associated with dam operations of relatively lower monthly volume (about 227 m3/s) than steady flows associated with dam operations

Application of wavelet analysis for monitoring the hydrologic effects of dam operation: Glen canyon dam and the Colorado River at lees ferry, Arizona

USGS Publications Warehouse

White, M.A.; Schmidt, J.C.; Topping, D.J.

2005-01-01

Wavelet analysis is a powerful tool with which to analyse the hydrologic effects of dam construction and operation on river systems. Using continuous records of instantaneous discharge from the Lees Ferry gauging station and records of daily mean discharge from upstream tributaries, we conducted wavelet analyses of the hydrologic structure of the Colorado River in Grand Canyon. The wavelet power spectrum (WPS) of daily mean discharge provided a highly compressed and integrative picture of the post-dam elimination of pronounced annual and sub-annual flow features. The WPS of the continuous record showed the influence of diurnal and weekly power generation cycles, shifts in discharge management, and the 1996 experimental flood in the post-dam period. Normalization of the WPS by local wavelet spectra revealed the fine structure of modulation in discharge scale and amplitude and provides an extremely efficient tool with which to assess the relationships among hydrologic cycles and ecological and geomorphic systems. We extended our analysis to sections of the Snake River and showed how wavelet analysis can be used as a data mining technique. The wavelet approach is an especially promising tool with which to assess dam operation in less well-studied regions and to evaluate management attempts to reconstruct desired flow characteristics. Copyright ?? 2005 John Wiley & Sons, Ltd.

Biological data for water in Lake Powell and from Glen Canyon Dam releases, Utah and Arizona, 1990–2009

USGS Publications Warehouse

Vernieu, William S.

2015-10-06

The results of these analyses are presented in this report. From this record, further interpretation may be made concerning primary and secondary production in Lake Powell. These data provide a linkage between physical and chemical water-quality data and fisheries investigations in Lake Powell. They also provide information regarding the export of biological material from Glen Canyon Dam.

Status and trends of the rainbow trout population in the Lees Ferry reach of the Colorado River downstream from Glen Canyon Dam, Arizona, 1991–2009

USGS Publications Warehouse

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

2011-01-01

The Lees Ferry reach of the Colorado River, a 25-kilometer segment of river located immediately downstream from Glen Canyon Dam, has contained a nonnative rainbow trout (Oncorhynchus mykiss) sport fishery since it was first stocked in 1964. The fishery has evolved over time in response to changes in dam operations and fish management. Long-term monitoring of the rainbow trout population downstream of Glen Canyon Dam is an essential component of the Glen Canyon Dam Adaptive Management Program. A standardized sampling design was implemented in 1991 and has changed several times in response to independent, external scientific-review recommendations and budget constraints. Population metrics (catch per unit effort, proportional stock density, and relative condition) were estimated from 1991 to 2009 by combining data collected at fixed sampling sites during this time period and at random sampling sites from 2002 to 2009. The validity of combining population metrics for data collected at fixed and random sites was confirmed by a one-way analysis of variance by fish-length class size. Analysis of the rainbow trout population metrics from 1991 to 2009 showed that the abundance of rainbow trout increased from 1991 to 1997, following implementation of a more steady flow regime, but declined from about 2000 to 2007. Abundance in 2008 and 2009 was high compared to previous years, which was likely the result of increased early survival caused by improved habitat conditions following the 2008 high-flow experiment at Glen Canyon Dam. Proportional stock density declined between 1991 and 2006, reflecting increased natural reproduction and large numbers of small fish in samples. Since 2001, the proportional stock density has been relatively stable. Relative condition varied with size class of rainbow trout but has been relatively stable since 1991 for fish smaller than 152 millimeters (mm), except for a substantial decrease in 2009. Relative condition was more variable for larger

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

Financial Analysis of Experimental Releases Conducted at Glen Canyon Dam during Water Year 2013

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

Graziano, Diane; Poch, Leslie A.; Veselka, Thomas D.

2014-06-01

This report examines the financial implications of experimental flows conducted at the Glen Canyon Dam (GCD) in water year 2013. It is the fifth report in a series examining the financial implications of experimental flows conducted since the Record of Decision (ROD) was adopted in February 1997 (Reclamation 1996). A report released in January 2011 examined water years 1997 to 2005 (Veselka et al. 2011), a report released in August 2011 examined water years 2006 to 2010 (Poch et al. 2011), a report released June 2012 examined water year 2011 (Poch et al. 2012), and a report released April 2013more » examined water year 2012 (Poch et al. 2013).« less

Financial analysis of experimental releases conducted at Glen Canyon Dam during Water Year 2013

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

Graziano, D. J.; Poch, L. A.; Veselka, T. D.

2014-08-18

This report examines the financial implications of experimental flows conducted at the Glen Canyon Dam (GCD) in water year 2013. It is the fifth report in a series examining the financial implications of experimental flows conducted since the Record of Decision (ROD) was adopted in February 1997 (Reclamation 1996). A report released in January 2011 examined water years 1997 to 2005 (Veselka et al. 2011), a report released in August 2011 examined water years 2006 to 2010 (Poch et al. 2011), a report released June 2012 examined water year 2011 (Poch et al. 2012), and a report released April 2013more » examined water year 2012 (Poch et al. 2013).« less

Lava Flows in the Grand Canyon

NASA Technical Reports Server (NTRS)

2003-01-01

Over vast expanses of time, natural processes like floods and volcanoes deposit layers of rock on the Earth's surface. To delve down through layers of rock is to explore our planet's history. Sometimes rock layers are exposed through human activity, such as drilling or excavation. Other times, rivers carve through the rock. One of the best, and most well-known, examples of a river exposing ancient rocks is Colorado River in Arizona's Grand Canyon. What fewer people know is that the Grand Canyon also has a history of relatively recent (on geologic time scales) volcanism. The evidence--hardened lava--spills down the canyon walls all the way to the river. On June 22, 2003, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the Grand Canyon, near 36.2 degrees north latitude and 113.2 degrees west longitude. ASTER detects light visible to human eyes as well as 'invisible' infrared light. Because different minerals reflect different portions of the light spectrum, ASTER can see varying mineral compositions of the rocks it observes, as well as detecting vegetation. In this three-dimensional visualization, lava fields appear brownish gray, darker than the layers of limestone, sandstone and other rock in the canyon. Vegetation appears green, and sparsely vegetated areas appear mustard. Water in the Colorado River is blue-purple. Geologists estimate that between 1.8 million and 400,000 years ago, lava flows actually dammed the Colorado River more than a dozen times. Some of the lava dams were as high as 600 meters (about 1,969 feet), forming immense reservoirs. Over time, enough water and sediment built up to push the river flow over the tops of these dams and eventually erode them away. Today, remnants of these lava dams remain throughout the area, along with the much older rock layers they cover. Among the most well known examples of these 'frozen' lava cascades is Lava Falls, which spills down to the

Macroinvertebrate diets reflect tributary inputs and turbidity-driven changes in food availability in the Colorado River downstream of Glen Canyon Dam

USGS Publications Warehouse

Wellard Kelly, Holly A.; Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Hall, Robert O.; Cross, Wyatt F.; Baxter, Colden V.

2013-01-01

Physical changes to rivers associated with large dams (e.g., water temperature) directly alter macroinvertebrate assemblages. Large dams also may indirectly alter these assemblages by changing the food resources available to support macroinvertebrate production. We examined the diets of the 4 most common macroinvertebrate taxa in the Colorado River through Glen and Grand Canyons, seasonally, at 6 sites for 2.5 y. We compared macroinvertebrate diet composition to the composition of epilithon (rock and cliff faces) communities and suspended organic seston to evaluate the degree to which macroinvertebrate diets tracked downstream changes in resource availability. Diets contained greater proportions of algal resources in the tailwater of Glen Canyon Dam and more terrestrial-based resources at sites downstream of the 1st major tributary. As predicted, macroinvertebrate diets tracked turbidity-driven changes in resource availability, and river turbidity partially explained variability in macroinvertebrate diets. The relative proportions of resources assimilated by macroinvertebrates ranged from dominance by algae to terrestrial-based resources, despite greater assimilation efficiencies for algal than terrestrial C. Terrestrial resources were most important during high turbidity conditions, which occurred during the late-summer monsoon season (July–October) when tributaries contributed large amounts of organic matter to the mainstem and suspended sediments reduced algal production. Macroinvertebrate diets were influenced by seasonal changes in tributary inputs and turbidity, a result suggesting macroinvertebrate diets in regulated rivers may be temporally dynamic and driven by tributary inputs.

1. 'SANTA ANA RIVER IN SANTA ANA CANYON. ORANGE COUNTY.' ...

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

1. 'SANTA ANA RIVER IN SANTA ANA CANYON. ORANGE COUNTY.' This is an oblique aerial view to the northeast taken from the northeast extremity of the canyon, showing, in the middle distance, the confluence of Chino Creek and the Santa Ana River, site of the future Prado Dam. File number written on negative: R & H 80 026. - Prado Dam, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

Origin of the Colorado River experimental flood in Grand Canyon

USGS Publications Warehouse

Andrews, E.D.; Pizzi, L.A.

2000-01-01

The Colorado River is one of the most highly regulated and extensively utilized rivers in the world. Total reservoir storage is approximately four times the mean annual runoff of ~17 x 109 m3 year -1. Reservoir storage and regulation have decreased annual peak discharges and hydroelectric power generation has increased daily flow variability. In recent years, the incidental impacts of this development have become apparent especially along the Colorado River through Grand Canyon National Park downstream from Glen Canyon Dam and caused widespread concern. Since the completion of Glen Canyon Dam, the number and size of sand bars, which are used by recreational river runners and form the habitat for native fishes, have decreased substantially. Following an extensive hydrological and geomorphic investigation, an experimental flood release from the Glen Canyon Dam was proposed to determine whether sand bars would be rebuilt by a relatively brief period of flow substantially greater than the normal operating regime. This proposed release, however, was constrained by the Law of the River, the body of law developed over 70 years to control and distribute Colorado River water, the needs of hydropower users and those dependent upon hydropower revenues, and the physical constraints of the dam itself. A compromise was reached following often difficult negotiations and an experimental flood to rebuild sand bars was released in 1996. This flood, and the process by which it came about, gives hope to resolving the difficult and pervasive problem of allocation of water resources among competing interests.The Colorado River is one of the most highly regulated and extensively utilized rivers in the world. Total reservoir storage is approximately four times the mean annual runoff of approximately 17??109 m3 year-1. Reservoir storage and regulation have decreased annual peak discharges and hydroelectric power generation has increased daily flow variability. In recent years, the

Hells Canyon to the Bitterroot front: A transect from the accretionary margin eastward across the Idaho batholith

USGS Publications Warehouse

Lewis, Reed S.; Smith, Keegan L.; Gaschnig, Richard M.; LaMaskin, Todd A.; Lund, Karen; Gray, Keith D.; Tikoff, Basil; Stetson-Lee, Tor; Moore, Nicholas

2014-01-01

This field guide covers geology across north-central Idaho from the Snake River in the west across the Bitterroot Mountains to the east to near Missoula, Montana. The regional geology includes a much-modified Mesozoic accretionary boundary along the western side of Idaho across which allochthonous Permian to Cretaceous arc complexes of the Blue Mountains province to the west are juxtaposed against autochthonous Mesoproterozoic and Neoproterozoic North American metasedimentary assemblages intruded by Cretaceous and Paleogene plutons to the east. The accretionary boundary turns sharply near Orofino, Idaho, from north-trending in the south to west-trending, forming the Syringa embayment, then disappears westward under Miocene cover rocks of the Columbia River Basalt Group. The Coolwater culmination east of the Syringa embayment exposes allochthonous rocks well east of an ideal steep suture. North and east of it is the Bitterroot lobe of the Idaho batholith, which intruded Precambrian continental crust in the Cretaceous and Paleocene to form one of the classical North American Cordilleran batholiths. Eocene Challis plutons, products of the Tertiary western U.S. ignimbrite flare-up, intrude those batholith rocks. This guide describes the geology in three separate road logs: (1) The Wallowa terrane of the Blue Mountains province from White Bird, Idaho, west into Hells Canyon and faults that complicate the story; (2) the Mesozoic accretionary boundary from White Bird to the South Fork Clearwater River east of Grangeville and then north to Kooskia, Idaho; and (3) the bend in the accretionary boundary, the Coolwater culmination, and the Bitterroot lobe of the Idaho batholith along Highway 12 east from near Lewiston, Idaho, to Lolo, Montana.

Ex post power economic analysis of record of decision operational restrictions at Glen Canyon Dam.

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

Veselka, T. D.; Poch, L. A.; Palmer, C. S.

On October 9, 1996, Bruce Babbitt, then-Secretary of the U.S. Department of the Interior signed the Record of Decision (ROD) on operating criteria for the Glen Canyon Dam (GCD). Criteria selected were based on the Modified Low Fluctuating Flow (MLFF) Alternative as described in the Operation of Glen Canyon Dam, Colorado River Storage Project, Arizona, Final Environmental Impact Statement (EIS) (Reclamation 1995). These restrictions reduced the operating flexibility of the hydroelectric power plant and therefore its economic value. The EIS provided impact information to support the ROD, including an analysis of operating criteria alternatives on power system economics. This exmore » post study reevaluates ROD power economic impacts and compares these results to the economic analysis performed prior (ex ante) to the ROD for the MLFF Alternative. On the basis of the methodology used in the ex ante analysis, anticipated annual economic impacts of the ROD were estimated to range from approximately $15.1 million to $44.2 million in terms of 1991 dollars ($1991). This ex post analysis incorporates historical events that took place between 1997 and 2005, including the evolution of power markets in the Western Electricity Coordinating Council as reflected in market prices for capacity and energy. Prompted by ROD operational restrictions, this analysis also incorporates a decision made by the Western Area Power Administration to modify commitments that it made to its customers. Simulated operations of GCD were based on the premise that hourly production patterns would maximize the economic value of the hydropower resource. On the basis of this assumption, it was estimated that economic impacts were on average $26.3 million in $1991, or $39 million in $2009.« less

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

A sand budget for Marble Canyon, Arizona: implications for long-term monitoring of sand storage change

USGS Publications Warehouse

Grams, Paul E.

2013-01-01

Recent U.S. Geological Survey research is providing important insights into how best to monitor changes in the amount of tributary-derived sand stored on the bed of the Colorado River and in eddies in Marble Canyon, Arizona. Before the construction of Glen Canyon Dam and other dams upstream, sandbars in Glen, Marble, and Grand Canyons were replenished each year by sediment-rich floods. Sand input into the Colorado River is crucial to protecting endangered native fish, animals, and plants and cultural and recreational resources along the river in Glen Canyon National Recreation Area and Grand Canyon National Park.

The Black Canyon of the Gunnison: Today and Yesterday

USGS Publications Warehouse

Hansen, Wallace R.

1965-01-01

Since the early visit of Captain John William Gunnison in the middle of the last century, the Black Canyon of the Gunnison has stirred mixed apprehension and wonder in the hearts of its viewers. It ranks high among the more awesome gorges of North America. Many great western canyons are as well remembered for their brightly colored walls as for their airy depths. Not so the Black Canyon. Though it is assuredly not black, the dark-gray tones of its walls and the hazy shadows of its gloomy depths join together to make its name well deserved. Its name conveys an impression, not a picture. After the first emotional impact of the canyon, the same questions come to the minds of most reflective viewers and in about the following order: How deep is the Black Canyon, how wide, how does it compare with other canyons, what are the rocks, how did it form, and how long did it take? Several western canyons exceed the Black Canyon in overall size. Some are longer; some are deeper; some are narrower; and a few have walls as steep. But no other canyon in North American combines the depth, narrowness, sheerness, and somber countenance of the Black Canyon. In many places the Black Canyon is as deep as it is wide. Between The Narrows and Chasm View in the Black Canyon of the Gunnison National Monument (fig. 15) it is much deeper than wide. Average depth in the monument is about 2,000 feet, ranging from a maximum of about 2,700 feet, north of Warner Point (which also is the greatest depth anywhere in the canyon), to a minimum of about 1,750 feet at The Narrows. The stretch of canyon between Pulpit Rock and Chasm View, including The Narrows, though the shallowest in the monument, is also the narrowest, has some of the steepest walls, and is, therefore, among the most impressive segments of the canyon (fig. 3). Profiles of several well-known western canyons are shown in figure 1. Deepest of these by far is Hells Canyon of the Snake, on the Idaho-Oregon border. Clearly, it dwarfs the

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

Planned flooding and Colorado River riparian trade-offs downstream from Glen Canyon Dam, Arizona

USGS Publications Warehouse

Stevens, Lawrence E.; Ayers, T.J.; Bennett, J.B.; Christensen, K.; Kearsley, M.J.C.; Meretsky, V.J.; Phillips, A. M.; Parnell, R.A.; Spence, J.; Sogge, M.K.; Springer, A.E.; Wegner, D.L.

2001-01-01

Regulated river restoration through planned flooding involves trade-offs between aquatic and terrestrial components, between relict pre-dam and novel post-dam resources and processes, and between management of individual resources and ecosystem characteristics. We review the terrestrial (wetland and riparian) impacts of a 1274 m3/s test flood conducted by the U.S. Bureau of Reclamation in March/April 1996, which was designed to improve understanding of sediment transport and management downstream from Glen Canyon Dam in the Colorado River ecosystem. The test flood successfully restored sandbars throughout the river corridor and was timed to prevent direct impacts to species of concern. A total of 1275 endangered Kanab ambersnail (Oxyloma haydeni kanabensis) were translocated above the flood zone at Vaseys Paradise spring, and an estimated 10.7% of the total snail habitat and 7.7% of the total snail population were lost to the flood. The test flood scoured channel margin wetlands, including potential foraging habitats of endangered Southwestern Willow Flycatcher (Empidonax traillii extimus). It also buried ground-covering riparian vegetation under >1 m of fine sand but only slightly altered woody sandbar vegetation and some return-current channel marshes. Pre-flood control efforts and appropriate flood timing limited recruitment of four common nonnative perennial plant species. Slight impacts on ethnobotanical resources were detected >430 km downstream, but those plant assemblages recovered rapidly. Careful design of planned flood hydrograph shape and seasonal timing is required to mitigate terrestrial impacts during efforts to restore essential fluvial geomorphic and aquatic habitats in regulated river ecosystems.

The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

USGS Publications Warehouse

Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

2014-01-01

Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

Financial Analysis of Experimental Releases Conducted at Glen Canyon Dam during Water Year 2014

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

Graziano, D. J.; Poch, L. A.; Veselka, T. D.

This report examines the financial implications of experimental flows conducted at the Glen Canyon Dam (GCD) in water year (WY) 2014. It is the sixth report in a series examining the financial implications of experimental flows conducted since the Record of Decision (ROD) was adopted in February 1997 (Reclamation 1996). A report released in January 2011 examined water years 1997 to 2005 (Veselka et al. 2011), a report released in August 2011 examined water years 2006 to 2010 (Poch et al. 2011), a report released June 2012 examined water year 2011 (Poch et al. 2012), a report released April 2013more » examined water year 2012 (Poch et al. 2013), and a report released June 2014 examined water year 2013 (Graziano et al. 2014).« less

Summary report of responses of key resources to the 2000 Low Steady Summer Flow experiment, along the Colorado River downstream from Glen Canyon Dam, Arizona

USGS Publications Warehouse

Ralston, Barbara E.

2011-01-01

In the spring and summer of 2000, a series of steady discharges of water from Glen Canyon Dam on the Colorado River were used to evaluate the effects of aquatic habitat stability and water temperatures on native fish growth and survival, with a special focus on the endangered humpback chub (Gila cypha), downstream from the dam in Grand Canyon. The steady releases were bracketed by peak powerplant releases in late-May and early-September. The duration and volume of releases from the dam varied between spring and summer. The intent of the experimental hydrograph was to mimic predam river discharge patterns by including a high, steady discharge in the spring and a low, steady discharge in the summer. The hydrologic experiment was called the Low Steady Summer Flow (LSSF) experiment because steady discharges of 226 m3/s dominated the hydrograph for 4 months from June through September 2000. The experimental hydrograph was developed in response to one of the U.S. Fish and Wildlife Service's Recommended and Prudent Alternatives (RPA) in its Biological Opinion of the Operation of Glen Canyon Dam Final Environmental Impact Statement. The RPA focused on the hypothesis that seasonally adjusted steady flows were dam operations that might benefit humpback chub more than the Record of Decision operations, known as Modified Low Fluctuating Flow (MLFF) operations. Condensed timelines between planning and implementation (2 months) of the experiment and the time required for logistics, purchasing, and contracting resulted in limited data collection during the high-release part of the experiment that occurred in spring. The LSSF experiment is the longest planned hydrograph that departed from the MLFF operations since Record of Decision operations began in 1996. As part of the experiment, several studies focused on the responses of physical properties related to environments that young-of-year (YOY) native fish might occupy (for example, measuring mainstem and shoreline water

Refraction tomography mapping of near-surface dipping layers using landstreamer data at East Canyon Dam, Utah

USGS Publications Warehouse

Ivanov, J.; Miller, R.D.; Markiewicz, R.D.; Xia, J.

2008-01-01

We apply the P-wave refraction-tomography method to seismic data collected with a landstreamer. Refraction-tomography inversion solutions were determined using regularization parameters that provided the most realistic near-surface solutions that best matched the dipping layer structure of nearby outcrops. A reasonably well matched solution was obtained using an unusual set of optimal regularization parameters. In comparison, the use of conventional regularization parameters did not provide as realistic results. Thus, we consider that even if there is only qualitative a-priori information about a site (i.e., visual) - in the case of the East Canyon Dam, Utah - it might be possible to minimize the refraction nonuniqueness by estimating the most appropriate regularization parameters.

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.

A paleolimnological investigation of historical environmental change in East Canyon Reservoir

NASA Astrophysics Data System (ADS)

Higby Halseth, Deanna Renee

East Canyon Reservoir is located 32 km east of Salt Lake City, Utah, and serves as a resource for irrigation, culinary water, and recreation. This research used paleolimnology and historical records to investigate the impacts of multiple stressors, including land clearance, dam construction and enlargement, and climate warming on East Canyon Reservoir. Recently, blue green algal blooms, typically indicative of eutrophication, have been increasing at East Canyon Reservoir despite reductions of nutrients from point sources, so part of the impetus for this study was to understand the forcing mechanisms of these blooms. A multiproxy analysis of three sediment cores retrieved from the reservoir determined changes in nutrient concentrations and sediment composition over time. Percent organics, magnetic susceptibility, and diatom analyses of 210Pb dated cores were compared to measurements of temperature and precipitation as well as records of historical land use, which were determined using remote sensing. Percent organics and magnetic susceptibility showed changes related to dam construction and increased development. Fossil diatom assemblages indicated that East Canyon Reservoir had been eutrophic since origination; however, principal components analyses of the diatom data indicated that the canyon became more P-enriched following dam construction and increased development. Recent increases in Cyclotella diatoms indicate changes related to warming temperatures, and we speculate that this warming is also what is causing blue-green algal blooms to increase.

Sand pulses and sand patches on the Colorado River in Grand Canyon

USGS Publications Warehouse

Grams, Paul E.; Buscombe, Daniel; Topping, David; Mueller, Erich R.

2017-01-01

Alluvial sandbars occur in lateral recirculation zones (eddies) along the Colorado River in Grand Canyon National Park (Schmidt, 1990). Resource managers periodically release controlled floods from the upstream Glen Canyon Dam to rebuild these bars (Grams et al., 2015), which erode during fluctuating dam releases, and by hillslope runoff and wind deflation (Hazel et al., 2010). Because the dam blocks upstream sediment, episodic floods from tributaries provide the only supply to replace eroded sand; and much of this sand originates from a single tributary (Topping et al., 2000). Here, we present new evidence for the downstream translation of the sand component of these sediment inputs as discontinuous sand pulses. Improved understanding of the behaviour of these sand pulses may be used to adjust the timing, magnitude, and duration of controlled floods to maximize potential for deposition on sandbars in different segments of the 450 km-long Grand Canyon.

Is there enough sand? Evaluating the fate of Grand Canyon sandbars

USGS Publications Warehouse

Wright, S.A.; Schmidt, J.C.; Meles, T.S.; Topping, D.J.; Rubin, D.M.

2008-01-01

Large dams have the potential to dramatically alter the flow regime, geomorphology, and aquatic ecosystem of downstream river reaches. Development of flow release regimes in order to meet multiple objectives is a challenge facing dam operators, resource managers, and scientists. Herein, we review previous work and present new analyses related to the effects of Glen Canyon Dam on the downstream reach of the Colorado River in Marble and Grand Canyons. The dam traps the entire incoming sediment load in Lake Powell and modulates the hydrologic regime by, for example, eliminating spring snowmelt floods, resulting in changes in the geomorphology of the river downstream. The primary geomorphic impact has been the erosion of sandbars along the banks of the river. Recognition of this impact has led to many scientific studies and a variety of experimental operations of Glen Canyon Dam with the goal of rebuilding the eroding sandbars. These efforts have thus far been generally unsuccessful and the question remains as to whether or not the dam can be operated such that sandbars can be rebuilt and maintained over extended periods with the existing sediment supply. We attempt to answer this question by evaluating a dam operation that may be considered a "best-case scenario" for rebuilding and maintaining eroded sandbars. Our analysis suggests that this best-case scenario may indeed have viability for rebuilding sandbars, and that the initial rate at which sandbars could be rebuilt is comparable to the rate at which sandbars have been eroded since dam construction. The question remains open as to the viability of operations that deviate from the best-case scenario that we have defined.

Effects of the 2008 high-flow experiment on water quality in Lake Powell and Glen Canyon Dam releases, Utah-Arizona

USGS Publications Warehouse

Vernieu, William S.

2010-01-01

Under the direction of the Secretary of the Interior, the U.S. Geological Survey`s Grand Canyon Monitoring and Research Center (GCMRC) conducted a high-flow experiment (HFE) at Glen Canyon Dam (GCD) from March 4 through March 9, 2008. This experiment was conducted under enriched sediment conditions in the Colorado River within Grand Canyon and was designed to rebuild sandbars, aid endangered humpback chub (Gila cypha), and benefit various downstream resources, including rainbow trout (Oncorhynchus mykiss), the aquatic food base, riparian vegetation, and archaeological sites. During the experiment, GCD discharge increased to a maximum of 1,160 m3/s and remained at that rate for 2.5 days by near-capacity operation of the hydroelectric powerplant at 736 m3/s, augmented by discharge from the river outlet works (ROW) at 424 m3/s. The ROW releases water from Lake Powell approximately 30 m below the powerplant penstock elevation and bypasses the powerplant turbines. During the HFE, the surface elevation of Lake Powell was reduced by 0.8 m. This report describes studies that were conducted before and after the experiment to determine the effects of the HFE on (1) the stratification in Lake Powell in the forebay immediately upstream of GCD and (2) the water quality of combined GCD releases and changes that occurred through the tailwater below the dam. The effects of the HFE to the water quality and stratigraphy in the water column of the GCD forebay and upstream locations in Lake Powell were minimal, compared to those during the beach/habitat-building flow experiment conducted in 1996, in which high releases of 1,273 m3/s were sustained for a 9-day period. However, during the 2008 HFE, there was evidence of increased advective transport of reservoir water at the penstock withdrawal depth and subsequent mixing of this withdrawal current with water above and below this depth. Reservoir hydrodynamics during the HFE period were largely being controlled by a winter inflow

Multiyear Downstream Response to Dam Removal on the White Salmon River, WA

NASA Astrophysics Data System (ADS)

Wilcox, A. C.; O'Connor, J. E.; Major, J. J.

2017-12-01

The 2011 removal of the 38 m tall Condit Dam on the White Salmon River, Washington was one of the largest dam removals to date, in terms of both dam height and sediment release. We examined the multiyear geomorphic response to this event, through 2015, including in a bedrock-confined canyon and in a less-confined, backwater-influenced pool reach near the river's mouth, to the large, rapid influx of fine reservoir sediment produced by the breach and to subsequent sediment transfer in the free-flowing White Salmon River. In the canyon reach, aggraded sediments were rapidly eroded from riffles, returning them toward pre-breach bed elevations within weeks, but pool aggradation persisted for longer. The downstream, less-confined reach transformed from a deep pool to a narrower pool-riffle channel with alternate bars; multiyear observations showed persistence of bars and of this new and distinct morphology. This downstream reach marks a rare case in post-dam removal channel response; in most dam removals, channels have rapidly reverted toward pre-removal morphology, as in the canyon reach here. Comparison of the multiyear geomorphic evolution of the White Salmon River to other recent large dam removals in the U.S. allows evaluation of the relative influences of antecedent channel morphology, post-breach hydrology, and dam removal style, as well as providing a basis for predicting responses to future dam removals.

Debris flow deposition and reworking by the Colorado River in Grand Canyon, Arizona

USGS Publications Warehouse

Yanites, Brian J.; Webb, Robert H.; Griffiths, Peter G.; Magirl, Christopher S.

2006-01-01

Flow regulation by large dams affects downstream flow competence and channel maintenance. Debris flows from 740 tributaries in Grand Canyon, Arizona, transport coarse‐grained sediment onto debris fans adjacent to the Colorado River. These debris fans constrict the river to form rapids and are reworked during river flows that entrain particles and transport them downstream. Beginning in 1963, flood control operations of Glen Canyon Dam limited the potential for reworking of aggraded debris fans. We analyzed change in debris fans at the mouths of 75‐Mile and Monument Creeks using photogrammetry of aerial photography taken from 1965 to 2000 and supplemented with ground surveys performed from 1987 to 2005. Our results quantify the debris fan aggradation that resulted from debris flows from 1984 to 2003. Volume, area, and river constriction increased at both debris fans. Profiles of the two debris fans show that net aggradation occurred in the middle of debris fans at stages above maximum dam releases, and surface shape shifted from concave to convex. Dam releases above power plant capacity partially reworked both debris fans, although reworking removed much less sediment than what was added by debris flow deposition. Large dam releases would be required to create additional reworking to limit the rate of debris fan aggradation in Grand Canyon.

77 FR 51022 - Clark Canyon Hydro, LLC; Notice of Application Accepted for Filing, Ready for Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-23

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 12429-007] Clark Canyon... b. Project No.: 12429-007. c. Date Filed: May 31, 2012. d. Applicant: Clark Canyon Hydro, LLC . e. Name of Project: Clark Canyon Dam Hydroelectric Project. f. Location: When constructed, the project...

State-and-transition prototype model of riparian vegetation downstream of Glen Canyon Dam, Arizona

USGS Publications Warehouse

Ralston, Barbara E.; Starfield, Anthony M.; Black, Ronald S.; Van Lonkhuyzen, Robert A.

2014-01-01

Facing an altered riparian plant community dominated by nonnative species, resource managers are increasingly interested in understanding how to manage and promote healthy riparian habitats in which native species dominate. For regulated rivers, managing flows is one tool resource managers consider to achieve these goals. Among many factors that can influence riparian community composition, hydrology is a primary forcing variable. Frame-based models, used successfully in grassland systems, provide an opportunity for stakeholders concerned with riparian systems to evaluate potential riparian vegetation responses to alternative flows. Frame-based, state-and-transition models of riparian vegetation for reattachment bars, separation bars, and the channel margin found on the Colorado River downstream of Glen Canyon Dam were constructed using information from the literature. Frame-based models can be simple spreadsheet models (created in Microsoft® Excel) or developed further with programming languages (for example, C-sharp). The models described here include seven community states and five dam operations that cause transitions between states. Each model divides operations into growing (April–September) and non-growing seasons (October–March) and incorporates upper and lower bar models, using stage elevation as a division. The inputs (operations) can be used by stakeholders to evaluate flows that may promote dynamic riparian vegetation states, or identify those flow options that may promote less desirable states (for example, Tamarisk [Tamarix sp.] temporarily flooded shrubland). This prototype model, although simple, can still elicit discussion about operational options and vegetation response.

Grand Canyon riverbed sediment changes, experimental release of September 2000 - a sample data set

USGS Publications Warehouse

Wong, Florence L.; Anima, Roberto J.; Galanis, Peter; Codianne, Jennifer; Xia, Yu; Bucciarelli, Randy; Hamer, Michael

2003-01-01

An experimental water release from the Glen Canyon Dam into the Colorado River above Grand Canyon was conducted in September 2000 by the U.S. Bureau of Reclamation. The U.S. Geological Survey (USGS) conducted sidescan sonar surveys between Glen Canyon Dam (mile -15) and Diamond Creek (mile 220), Arizona (mile designations after Stevens, 1998) to determine the sediment characteristics of the Colorado River bed before and after the release. The first survey (R3-00-GC, 28 Aug to 5 Sep 2000) was conducted before the release when the river was at its Low Summer Steady Flow (LSSF) of 8,000 cfs. The second survey (R4-00-GC, 10 to 18 Sep 2000) was conducted immediately after the September 2000 experimental release when the average daily flow was as high as 30,800 cfs as measured below Glen Canyon Dam (Figure 2). Riverbed sediment properties interpreted from the sidescan sonar images include sediment type and sandwaves; overall changes in these properties between the two surveys were calculated. Sidescan sonar data from the USGS surveys were processed for segments of the Colorado River from Glen Canyon Dam (mile -15) to Phantom Ranch (mile 87.7, Figure 3). The surveys targeted pools between rapids that are part of the Grand Canyon Monitoring and Research Center (GCMRC http://www.gcmrc.gov/) physical sciences study. Maps interpreted from the sidescan sonar images show the distribution of sediment types (bedrock, boulders, pebbles or cobbles, and sand) and the extent of sandwaves for each of the pre- and post-flow surveys. The changes between the two surveys were calculated with spatial arithmetric and had properties of fining, coarsening, erosion, deposition, and the appearance or disappearance of sandwaves.

Short-Term Effects of the 2008 High-Flow Experiment on Macroinvertebrates in Colorado River Below Glen Canyon Dam, Arizona

USGS Publications Warehouse

Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Kincaid, Dustin W.; Cross, Wyatt F.; Kelly, Holly A.W.; Behn, Kathrine A.; White, Tyler; Hall, Robert O.; Baxter, Colden V.

2010-01-01

Glen Canyon Dam has dramatically altered the physical environment (especially discharge regime, water temperatures, and sediment inputs) of the Colorado River. High-flow experiments (HFE) that mimic one aspect of the natural hydrograph (floods) were implemented in 1996, 2004, and 2008. The primary goal of these experiments was to increase the size and total area of sandbar habitats that provide both camping sites for recreational users and create backwaters (areas of stagnant flow in the lee of return-current eddies) that may be important as rearing habitat for native fish. Experimental flows might also positively or negatively alter the rainbow trout (Oncorhynchus mykiss) sport fishery in the clear tailwater reach below Glen Canyon Dam, Ariz., and native fish populations in downstream reaches (for example, endangered humpback chub, Gila cypha) through changes in available food resources. We examined the short-term response of benthic macroinvertebrates to the March 2008 HFE at three sites [river mile 0 (RM 0, 15.7 miles downriver from the dam), RM 62, and RM 225] along the Colorado River downstream from Glen Canyon Dam by sampling immediately before and then 1, 7, 14, and 30 days after the HFE. We selected these sites because of their importance to management; RM 0 has a valuable trout fishery, and RM 62 is the location of the largest population of the endangered humpback chub in the Grand Canyon. In addition to the short-term collection of samples, as part of parallel investigations, we collected 3 years of monthly (quarterly for RM 62) benthic macroinvertebrate samples that included 15 months of post-HFE data for all three sites, but processing of the samples is only complete for one site (RM 0). At RM 0, the HFE caused an immediate 1.75 g AFDM/m2 (expressed as grams ash-free dry mass, or AFDM) reduction of macroinvertebrate biomass that was driven by significant reductions in the biomass of the two dominant taxa in this reach-Potamopyrgus antipodarum (New

Geologic map of the Glen Canyon Dam 30’ x 60’ quadrangle, Coconino County, northern Arizona

USGS Publications Warehouse

Billingsley, George H.; Priest, Susan S.

2013-01-01

The Glen Canyon Dam 30’ x 60’ quadrangle is characterized by nearly flat lying to gently dipping Paleozoic and Mesozoic sedimentary strata that overlie tilted Proterozoic strata or metasedimentary and igneous rocks similar to those exposed at the bottom of Grand Canyon southwest of the quadrangle. Mississippian to Permian rocks are exposed in the walls of Marble Canyon; Permian strata and minor outcrops of Triassic strata form the surface bedrock of House Rock Valley and Marble Plateau, southwestern quarter of the quadrangle. The Paleozoic strata exposed in Marble Canyon and Grand Canyon south of the map are likely present in the subsurface of the entire quadrangle but with unknown facies and thickness changes. The Mesozoic sedimentary rocks exposed along the Vermilion and Echo Cliffs once covered the entire quadrangle, but Cenozoic erosion has removed most of these rocks from House Rock Valley and Marble Plateau areas. Mesozoic strata remain over much of the northern and eastern portions of the quadrangle where resistant Jurassic sandstone units form prominent cliffs, escarpments, mesas, buttes, and much of the surface bedrock of the Paria, Kaibito, and Rainbow Plateaus. Jurassic rocks in the northeastern part of quadrangle are cut by a sub-Cretaceous regional unconformity that bevels the Entrada Sandstone and Morrison Formation from Cummings Mesa southward to White Mesa near Kaibito. Quaternary deposits, mainly eolian, mantle much of the Paria, Kaibito, and Rainbow Plateaus in the northern and northeastern portion of the quadrangle. Alluvial deposits are widely distributed over parts of House Rock Valley and Marble Plateau in the southwest quarter of the quadrangle. The east-dipping strata of the Echo Cliffs Monocline forms a general north-south structural boundary through the central part of the quadrangle, separating Marble and Paria Plateaus west of the monocline from the Kaibito Plateau east of the monocline. The Echo Cliffs Monocline continues north of

Geology and geomorphology of the Lower Deschutes River Canyon, Oregon.

Treesearch

Robin A. Beebee; Jim E. O' Connor; Gordon E. Grant

2002-01-01

This field guide is designed for geologists floating the approximately 80 kilometers (50 miles) of the Deschutes River from the Pelton-Round Butte Dam Complex west of Madras to Maupin, Oregon. The first section of the guide is a geologic timeline tracing the formation of the units that compose the canyon walls and the incision of the present canyon. The second section...

1000 dams down and counting

USGS Publications Warehouse

O'Connor, James E.; Duda, Jeff J.; Grant, Gordon E.

2015-01-01

Forty years ago, the demolition of large dams was mostly fiction, notably plotted in Edward Abbey's novel The Monkey Wrench Gang. Its 1975 publication roughly coincided with the end of large-dam construction in the United States. Since then, dams have been taken down in increasing numbers as they have filled with sediment, become unsafe or inefficient, or otherwise outlived their usefulness (1) (see the figure, panel A). Last year's removals of the 64-m-high Glines Canyon Dam and the 32-m-high Elwha Dam in northwestern Washington State were among the largest yet, releasing over 10 million cubic meters of stored sediment. Published studies conducted in conjunction with about 100 U.S. dam removals and at least 26 removals outside the United States are now providing detailed insights into how rivers respond (2, 3).

78 FR 17389 - Clark Canyon Hydro, LLC; Notice of Application for Amendment of License and Soliciting Comments...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-21

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 12429-009] Clark Canyon...: 12429-009. c. Date Filed: January 28, 2013. d. Applicant: Northwest Power Services on behalf of Clark Canyon Hydro, LLC. e. Name of Project: Clark Canyon Dam Hydroelectric Project. f. Location: The Clark...

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.

Estimating recruitment dynamics and movement of rainbow trout (Oncorhynchus mykiss) in the Colorado River in Grand Canyon using an integrated assessment model

USGS Publications Warehouse

Korman, Josh; Martell, Steven J.D.; Walters, Carl J.; Makinster, Andrew S.; Coggins, Lewis G.; Yard, Michael D.; Persons, William R.

2012-01-01

We used an integrated assessment model to examine effects of flow from Glen Canyon Dam, Arizona, USA, on recruitment of nonnative rainbow trout (Oncorhynchus mykiss) in the Colorado River and to estimate downstream migration from Glen Canyon to Marble Canyon, a reach used by endangered native fish. Over a 20-year period, recruitment of rainbow trout in Glen Canyon increased with the annual flow volume and when hourly flow variation was reduced and after two of three controlled floods. The model predicted that approximately 16 000 trout·year–1 emigrated to Marble Canyon and that the majority of trout in this reach originate from Glen Canyon. For most models that were examined, over 70% of the variation in emigration rates was explained by variation in recruitment in Glen Canyon, suggesting that flow from the dam controls in large part the extent of potential negative interactions between rainbow trout and native fish. Controlled floods and steadier flows, which were originally aimed at partially restoring conditions before the dam (greater native fish abundance and larger sand bars), appear to have been more beneficial to nonnative rainbow trout than to native fish.

Quaternary Basalts in Grand Canyon: Correlation of Flows Using Lidar, 40Ar/39Ar Dating, Geochemical Correlation, Neotectonic Studies, and History of Lava Dams

NASA Astrophysics Data System (ADS)

Crow, R. S.; Karlstrom, K. E.; McIntosh, W. C.; Dunbar, N. W.; Peters, L.; Raucci, J.; Umhoefer, P. J.

2005-12-01

In western Grand Canyon, basalts flowed into the already existing canyon from at least 719 ka to present. These basalts provide a key for deciphering Quaternary rates of incision, neotectonic slip rates on the Toroweap and Hurricane faults, and the history of lava dams. Stratigraphy and/or inset relationships between basalt flows is exceedingly complex because of the multiple eruptions, extreme topography, long transport distance, and incomplete preservation. Correlation of flows using 40Ar/39Ar dating, LIDAR data, orthophotography, and geochemical analysis, as well as structural and geomorphic studies, lead to a working hypothesis for four major episodes of basaltic eruptive activity. From 719 to 484 Ma major volcanoes erupted near the Toroweap fault zone. The extent of the remnants and presence of 527 ka dikes indicates that cones where built within Grand Canyon during this phase. These flows had the longest outflow (719 ka flow at mile 246). At 349 to 296 ka flows seem to have entered the canyon at Whitmore Wash, north rim. The two remaining episodes, dated at 199-193 ka and 109-97 ka are interpreted to have cascaded into the canyon at and upstream from Whitmore Wash. LIDAR/orthophotography interpretation of the tops and bottoms of the flows and geochemical analysis of phenocrysts aid in correlation of undated remnants and reconstructing the shape of volcanic edifices. Flows dated from 720-450 ka include Prospect, Black Ledge, D-Dam, and Toroweap flows, thus Black Ledge flows are considerably older than previously thought. The 350 to 300 flows include Whitmore, Layered Diabase, Massive Diabase, and 177-mile flows. All the dated 200 and 100 ka flows have been called Grey Ledge flows, suggesting that the Grey Ledge represents two distinct events. Basalt data indicate an interaction of canyon incision and Quaternary fault slip. Bedrock incision rates are calculated using dated flows that overly bedrock straths. Rates vary across active faults indicating fault

Use of flux and morphologic sediment budgets for sandbar monitoring on the Colorado River in Marble Canyon, Arizona

USGS Publications Warehouse

Grams, Paul E.; Buscombe, Daniel D.; Topping, David J.; Hazel, Joseph E.; Kaplinski, Matt

2015-01-01

The magnitude and pfattern of streamflow and sediment supply of the Colorado River in Grand Canyon (Figure 1) has been affected by the existence and operations of Glen Canyon Dam since filling of Lake Powell Reservoir began in March 1963. In the subsequent 30 years, fine sediment was scoured from the downstream channel (Topping et al., 2000; Grams et al., 2007), resulting in a decline in the number and size of sandbars in the eastern half of Grand Canyon National Park (Wright et al., 2005; Schmidt et al., 2004). The Glen Canyon Dam Adaptive Management Program (GCDAMP) administered by the U.S. Department of Interior oversees efforts to manage the Colorado River ecosystem downstream from Glen Canyon Dam. One of the goals of the GCDAMP is to maintain and increase the number and size of sandbars in this context of a limited sand supply. Management actions to benefit sandbars have included curtailment of daily streamflow fluctuations, which occur for hydropower generation, and implementation of controlled floods, also called high-flow experiments.Studies of controlled floods, defined as intentional releases that exceed the maximum discharge capacity of the Glen Canyon Dam powerplant, implemented between 1996 and 2008, have demonstrated that these events cause increases in sandbar size throughout Marble and Grand Canyons (Hazel et al., 2010; Schmidt and Grams, 2011; Mueller et al., 2014), although the magnitude of response is spatially variable (Hazel et al., 1999; 2010). Controlled floods may build some sandbars at the expense of erosion of sand from other, upstream, sandbars (Schmidt, 1999). To increase the frequency and effectiveness of sandbar building, the U.S. Department of Interior adopted a “high-flow experimental protocol” to implement controlled floods regularly under conditions of enriched sand supply (U.S. Department of Interior, 2012). Because the supply of sand available to build sandbars has been substantially reduced by Glen Canyon Dam (Topping et al

Late Pleistocene landslide-dammed lakes along the Rio Grande, White Rock Canyon, New Mexico

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

Reneau, S.L.; Dethier, D.P.

1996-11-01

Massive slump complexes composed of Pliocene basaltic rocks and underlying Miocene and Pliocene sediments flank the Rio Grande along 16 km of northern White Rock Canyon, New Mexico. The toe area of at least one slump complex was active in the late Pleistocene, damming the Rio Grande at least four times during the period from 18 to 12 {sup 14}C ka and impounding lakes that extended 10-20 km upriver. Stratigraphic relationships and radiocarbon age constraints indicate that three separate lakes formed between 13.7 and 12.4 {sup 14}C ka. The age and dimensions of the ca. 12.4 ka lake are bestmore » constrained; it had an estimated maximum depth of {approx}30 m, a length of {approx}13 km, a surface area of {approx}2.7 km{sup 2}, and an initial volume of {approx}2.5 x 10{sup 7} m{sup 3}. The youngest landslide-dammed lakes formed during a period of significantly wetter regional climate, strongly suggesting that climate changes were responsible for reactivation of the slump complexes. We are not certain about the exact triggering mechanisms for these landslides, but they probably involved removal of lateral support due to erosion of the slope base by the Rio Grande during periods of exceptionally high flood discharge or rapid incision; increased pore pressures associated with higher water tables; higher seepage forces at sites of ground-water discharge; or some combination of these processes. Seismic shaking could also have contributed to triggering of some of the landslides, particularly if aided by wet antecedent conditions. 54 refs., 19 figs., 3 tabs.« less

3. VIEW OF DIABLO CANYON LOOKING DOWNSTREAM FROM THE VALVE ...

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

3. VIEW OF DIABLO CANYON LOOKING DOWNSTREAM FROM THE VALVE HOUSE AT ELEVATION 1044, 1989. - Skagit Power Development, Diablo Dam, On Skagit River, 6.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

High-resolution topography and geomorphology of select archeological sites in Glen Canyon National Recreation Area, Arizona

USGS Publications Warehouse

Collins, Brian D.; Corbett, Skye C.; Sankey, Joel B.; Fairley, Helen C.

2014-01-01

Along the Colorado River corridor between Glen Canyon Dam and Lees Ferry, Arizona, located some 25 km downstream from the dam, archaeological sites dating from 8,000 years before present through the modern era are located within and on top of fluvial and alluvial terraces of the prehistorically undammed river. These terraces are known to have undergone significant erosion and retreat since emplacement of Glen Canyon Dam in 1963. Land managers and policy makers associated with managing the flow of the Colorado River are interested in understanding how the operations of Glen Canyon Dam have affected the archeological sites associated with these terraces and how dam-controlled flows currently interact with other landscape-shaping processes. In 2012, the U.S. Geological Survey initiated a research project in Glen Canyon to study the types and causes of erosion of the terraces. This report provides the first step towards this understanding by presenting comparative analyses on several types of high-resolution topographic data (airborne lidar, terrestrial lidar, and airborne photogrammetry) that can be used in the future to document and analyze changes to terrace-based archaeological sites. Herein, we present topographic and geomorphologic data of four archaeological sites within a 14 km segment of Glen Canyon using each of the three data sources. In addition to comparing each method’s suitability for adequately representing the topography of the sites, we also analyze the data within each site’s context and describe the geomorphological processes responsible for erosion. Our results show that each method has its own strengths and weaknesses, and that terrestrial and airborne lidar are essentially interchangeable for many important topographic characterization and monitoring purposes. However, whereas terrestrial lidar provides enhanced capacity for feature recognition and gully morphology delineation, airborne methods (whether by way of laser or optical sensors) are

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

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

Physical and chemical characteristics of Lake Powell at the forebay and outflows of Glen Canyon Dam, northeastern Arizona, 1990-91

USGS Publications Warehouse

Hart, R.J.; Sherman, K.M.

1996-01-01

The physical and chemical characteristics of Lake Powell have a direct effect on the quality of water below Glen Canyon Dam. Understanding the physical and chemical characteristics of the lake and outflows from the dam is essential in order to effectively manage the operation of the dam. During August 1990 to September 1991, physical and chemical measurements were made and water samples were collected in the forebay of Lake Powell and at the outflows (draft tubes) of Glen Canyon Dam to document the physical and chemical characteristics of water entering the Colorado River. A persistent chemocline in the forebay of Lake Powell fluctuated seasonally during the study. Thermal stratification began in mid-April and persisted into late October. Spatial variation of specific conductance, pH, water temperature, and dissolved-oxygen concentration in the forebay was negligible. Sodium and sulfate were the dominant ions. Major ions, nutrients, and metals generally increased in concentration with depth in the forebay. Concentrations of dissolved nitrogen (as nitrite plus nitrate) in the forebay ranged from less than 0.02 to 0.58 milligrams per liter. Strontium and lithium were the most abundant metals. Dissolved organic carbon ranged from about 2.6 to 4.9 milligrams per. liter with larger concentrations generally occurring in the epilimnion. No diel variations of chemical constituents were observed. Vertical-attenuation coefficients of light penetration in the forebay ranged from 0.058 to 0.080 microeinsteins per meter squared per second, and the euphotic depth ranged from about 82 to 113 feet. Generally, the physical and chemical characteristics of outflows through the draft tubes of Glen Canyon Dam were similar to the physical and chemical characteristics of the water at penstock depth and deeper depths. Specific conductance ranged from 803 to 1,090 microsiemens per centimeter, and pH values ranged from about 7.2 to 8.0. Water temperatures measured in the outflows ranged

Side-scan sonar imaging of the Colorado River, Grand Canyon

USGS Publications Warehouse

Anima, Roberto; Wong, Florence L.; Hogg, David; Galanis, Peter

2007-01-01

This paper presents data collection methods and side-scan sonar data collected along the Colorado River in Grand Canyon in August and September of 2000. The purpose of the data collection effort was to image the distribution of sand between Glen Canyon Dam and river mile 87.4 before and after the 31,600 cfs flow of September 6-8. The side-scan sonar imaging focused on pools between rapids but included smaller rapids where possible.

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

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

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

Riparian Vegetation Response to the March 2008 Short-Duration, High-Flow Experiment-Implications of Timing and Frequency of Flood Disturbance on Nonnative Plant Establishment Along the Colorado River Below Glen Canyon Dam

USGS Publications Warehouse

Ralston, Barbara E.

2010-01-01

Riparian plant communities exhibit various levels of diversity and richness. These communities are affected by flooding and are vulnerable to colonization by nonnative species. Since 1996, a series of three high-flow experiments (HFE), or water releases designed to mimic natural seasonal flooding, have been conducted at Glen Canyon Dam, Ariz., primarily to determine the effectiveness of using high flows to conserve sediment, a limited resource. These experiments also provide opportunities to examine the susceptibility of riparian plant communities to nonnative species invasions. The third and most recent HFE was conducted from March 5 to 9, 2008, and scientists with the U.S. Geological Survey's Grand Canyon Monitoring and Research Center examined the effects of high flows on riparian vegetation as part of the overall experiment. Total plant species richness, nonnative species richness, percent plant cover, percent organic matter, and total carbon measured from sediment samples were compared for Grand Canyon riparian vegetation zones immediately following the HFE and 6 months later. These comparisons were used to determine if susceptibility to nonnative species establishment varied among riparian vegetation zones and if the timing of the HFE affected nonnative plant establishment success. The 2008 HFE primarily buried vegetation rather than scouring it. Percent nonnative cover did not differ among riparian vegetation zones; however, in the river corridor affected by Glen Canyon Dam operations, nonnative species richness showed significant variation. For example, species richness was significantly greater immediately after and 6 months following the HFE in the hydrologic zone farthest away from the shoreline, the area that represents the oldest riparian zone within the post-dam riparian area. In areas closer to the river channel, tamarisk (Tamarix ramosissima X chinensis) seedling establishment occurred (<2 percent cover) in 2008 but not to the extent reported in

Monitoring and Evaluation of Yearling Fall Chinook Salmon (Oncorhynchus tshawytscha) Released from Acclimation Facilities Upstream of Lower Granite Dam; 1999 Annual Report.

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

Rocklage, Stephen J.; Kellar, Dale S.

2005-07-01

The Nez Perce Tribe, in cooperation with the U.S. Fish and Wildlife Service and Washington Department of Fish and Wildlife, conducted monitoring and evaluation studies on Lyons Ferry Hatchery reared yearling fall Chinook salmon Oncorhynchus tshawytscha that were acclimated and released at three Fall Chinook Acclimation Project (FCAP) sites upstream of Lower Granite Dam along with yearlings released on-station from Lyons Ferry Hatchery in 1999. This was the fourth year of a long-term project to supplement natural spawning populations of Snake River stock fall Chinook salmon upstream of Lower Granite Dam. The 453,117 yearlings released from the Fall Chinook Acclimationmore » Project facilities not only slightly exceeded the 450,000 fish quota, but a second release of 76,386 yearlings (hereafter called Surplus) were acclimated at the Big Canyon facility and released about two weeks after the primary releases. We use Passive Integrated Transponder (PIT) tag technology to monitor the primary performance measures of survival to mainstem dams and migration timing. We also monitor size, condition and tag/mark retention at release. We released 9,941 PIT tagged yearlings from Pittsburg Landing, 9,583 from Big Canyon, 2,511 Big Canyon Surplus and 2,494 from Captain John Rapids. The Washington Department of Fish and Wildlife released 983 PIT tagged yearlings from Lyons Ferry Hatchery. Fish health sampling indicated that, overall, bacterial kidney disease levels could be considered relatively low and did not appear to increase after transport to the acclimation facilities. Compared to prior years, Quantitative Health Assessment Indices were relatively low at Pittsburg Landing and Lyons Ferry Hatchery and relatively high at Big Canyon and Captain John Rapids. Mean fork lengths (95% confidence interval) of the release groups ranged from 147.4 mm (146.7-148.1 mm) at Captain John Rapids to 163.7 mm (163.3-164.1 mm) at Pittsburg Landing. Mean condition factors ranged from 1.04 at

Populating a Control Point Database: A cooperative effort between the USGS, Grand Canyon Monitoring and Research Center and the Grand Canyon Youth Organization

NASA Astrophysics Data System (ADS)

Brown, K. M.; Fritzinger, C.; Wharton, E.

2004-12-01

The Grand Canyon Monitoring and Research Center measures the effects of Glen Canyon Dam operations on the resources along the Colorado River from Glen Canyon Dam to Lake Mead in support of the Grand Canyon Adaptive Management Program. Control points are integral for geo-referencing the myriad of data collected in the Grand Canyon including aerial photography, topographic and bathymetric data used for classification and change-detection analysis of physical, biologic and cultural resources. The survey department has compiled a list of 870 control points installed by various organizations needing to establish a consistent reference for data collected at field sites along the 240 mile stretch of Colorado River in the Grand Canyon. This list is the foundation for the Control Point Database established primarily for researchers, to locate control points and independently geo-reference collected field data. The database has the potential to be a valuable mapping tool for assisting researchers to easily locate a control point and reduce the occurrance of unknowingly installing new control points within close proximity of an existing control point. The database is missing photographs and accurate site description information. Current site descriptions do not accurately define the location of the point but refer to the project that used the point, or some other interesting fact associated with the point. The Grand Canyon Monitoring and Research Center (GCMRC) resolved this problem by turning the data collection effort into an educational exercise for the participants of the Grand Canyon Youth organization. Grand Canyon Youth is a non-profit organization providing experiential education for middle and high school aged youth. GCMRC and the Grand Canyon Youth formed a partnership where GCMRC provided the logistical support, equipment, and training to conduct the field work, and the Grand Canyon Youth provided the time and personnel to complete the field work. Two data

Grand Canyon Humpback Chub Population Improving

USGS Publications Warehouse

Andersen, Matthew E.

2007-01-01

The humpback chub (Gila cypha) is a long-lived, freshwater fish found only in the Colorado River Basin. Physical adaptations-large adult body size, large predorsal hump, and small eyes-appear to have helped humpback chub evolve in the historically turbulent Colorado River. A variety of factors, including habitat alterations and the introduction of nonnative fishes, likely prompted the decline of native Colorado River fishes. Declining numbers propelled the humpback chub onto the Federal list of endangered species in 1967, and the species is today protected under the Endangered Species Act of 1973. Only six populations of humpback chub are currently known to exist, five in the Colorado River Basin above Lees Ferry, Ariz., and one in Grand Canyon, Ariz. The U.S. Geological Survey's Grand Canyon Monitoring and Research Center oversees monitoring and research activities for the Grand Canyon population under the auspices of the Glen Canyon Dam Adaptive Management Program (GCDAMP). Analysis of data collected through 2006 suggests that the number of adult (age 4+ years) humpback chub in Grand Canyon increased to approximately 6,000 fish in 2006, following an approximate 40-50 percent decline between 1989 and 2001. Increasing numbers of adult fish appear to be the result of steadily increasing numbers of juvenile fish reaching adulthood beginning in the mid- to late-1990s and continuing through at least 2002.

Using large-scale flow experiments to rehabilitate Colorado River ecosystem function in Grand Canyon: Basis for an adaptive climate-resilient strategy: Chapter 17

USGS Publications Warehouse

Melis, Theodore S.; Pine, William E.; Korman, Josh; Yard, Michael D.; Jain, Shaleen; Pulwarty, Roger S.; Miller, Kathleen; Hamlet, Alan F.; Kenney, Douglas S.; Redmond, Kelly T.

2016-01-01

Adaptive management of Glen Canyon Dam is improving downstream resources of the Colorado River in Glen Canyon National Recreation Area and Grand Canyon National Park. The Glen Canyon Dam Adaptive Management Program (AMP), a federal advisory committee of 25 members with diverse special interests tasked to advise the U.S. Department of the Interior), was established in 1997 in response to the 1992 Grand Canyon Protection Act. Adaptive management assumes that ecosystem responses to management policies are inherently complex and unpredictable, but that understanding and management can be improved through monitoring. Best known for its high-flow experiments intended to benefit physical and biological resources by simulating one aspect of pre-dam conditions—floods, the AMP promotes collaboration among tribal, recreation, hydropower, environmental, water and other natural resource management interests. Monitoring has shown that high flow experiments move limited new tributary sand inputs below the dam from the bottom of the Colorado River to shorelines; rebuilding eroded sandbars that support camping areas and other natural and cultural resources. Spring-timed high flows have also been shown to stimulate aquatic productivity by disturbing the river bed below the dam in Glen Canyon. Understanding about how nonnative tailwater rainbow trout (Oncorhynchus mykiss), and downstream endangered humpback chub (Gila cypha) respond to dam operations has also increased, but this learning has mostly posed “surprise” adaptation opportunities to managers. Since reoperation of the dam to Modified Low Fluctuating Flows in 1996, rainbow trout now benefit from more stable daily flows and high spring releases, but possibly at a risk to humpback chub and other native fishes downstream. In contrast, humpback chub have so far proven robust to all flows, and native fish have increased under the combination of warmer river temperatures associated with reduced storage in Lake Powell, and a

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.

The Role of Eolian Sediment in the Preservation of Archeologic Sites Along the Colorado River Corridor in Grand Canyon National Park, Arizona

USGS Publications Warehouse

Draut, Amy E.; Rubin, David M.

2008-01-01

Since the closure of Glen Canyon Dam in 1963, the natural hydrologic and sedimentary systems along the Colorado River in the Grand Canyon reach have changed substantially (see, for example, Andrews, 1986; Johnson and Carothers, 1987; Webb and others, 1999b; Rubin and others, 2002; Topping and others, 2003; Wright and others, 2005; Hazel and others, 2006b). The dam has reduced the fluvial sediment supply at the upstream boundary of Grand Canyon National Park by about 95 percent. Regulation of river discharge by dam operations has important implications for the storage and redistribution of sediment in the Colorado River corridor. In the absence of floods, sediment is not deposited at elevations that regularly received sediment before dam closure. Riparian vegetation has colonized areas at lower elevations than in predam time when annual floods removed young vegetation (Turner and Karpiscak, 1980). Together, these factors have caused a systemwide decrease in the size and number of subaerially exposed fluvial sand deposits since the 1960s, punctuated by episodic aggradation during the exceptional high-flow intervals in 1983-84, 1996, and 2004 and by sediment input from occasional tributary floods (Beus and others, 1985; Schmidt and Graf, 1987; Kearsley and others, 1994; Hazel and others, 1999; Schmidt and others, 2004; Wright and others, 2005). When the Bureau of Reclamation sponsored the creation of the Glen Canyon Environmental Studies (GCES) research initiative in 1982, research objectives included physical and biologic resources, whereas the effects of dam operations on cultural resources were not addressed (Fairley and others, 1994; Fairley, 2003). In the early 1980s, it was widely believed that because few archeologic sites were preserved within the river's annual-flood zone, cultural features would not be greatly affected by dam operations. Recent studies, however, indicate that alterations in the flow and sediment load of the Colorado River by Glen Canyon Dam

"The Great Cataract" - Effects of Late Holocene Debris Flows on Lava Falls Rapid, Grand Canyon National National Park, Arizona

USGS Publications Warehouse

Webb, Robert H.; Melis, Theodore S.; Wise, Thomas W.; Elliott, John G.

1996-01-01

Lava Falls Rapid is the most formidable reach of whitewater on the Colorado River in Grand Canyon and is one of the most famous rapids in the world. Although the rapid was once thought to be controlled by the remnants of lava dams of Pleistocene age, Lava Falls was created and is maintained by frequent debris flows from Prospect Canyon. We used 232 historical photographs, of which 121 were replicated, and 14C and 3He dating methods to reconstruct the ages and, in some cases, the magnitudes of late Holocene debris flows. We quantified the interaction between Prospect Canyon debris flows and the Colorado River using image processing of the historical photographs. The highest and oldest debris-flow deposits on the debris fan yielded a 3He date of 2.9?0.6 ka (950 BC), which indicates predominately late Holocene aggradation of one of the largest debris fans in Grand Canyon. The deposit, which has a 25-m escarpment caused by river reworking, crossed the Colorado River and raised its base level by 30 m for an indeterminate, although probably short, period. We mapped depositional surfaces of 6 debris flows that occurred after 950 BC. The most recent prehistoric debris flow occurred no more than 500 years ago (AD 1434). From April 1872 to July 1939, no debris flows occurred in Prospect Canyon. Debris flows in 1939, 1954, 1955, 1963, 1966, and 1995 constricted the Colorado River between 35 and 80 percent and completely changed the pattern of flow through the rapid. The debris flows had discharges estimated between about 290 and 1,000 m3/s and transported boulders as heavy as 30 Mg. The recurrence interval of these debris flows, calculated from the volume of the aggraded debris fan, ranged from 35 to 200 yrs. The 1939 debris flow in Prospect Canyon appears to have been the largest debris flow in Grand Canyon during the last 125 years. Debris flows in Prospect Canyon are initiated by streamflow pouring over a 325-m waterfall onto unconsolidated colluvium, a process called the

Annotated bibliography for the humpback chub (Gila cypha) with emphasis on the Grand Canyon population.

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

Goulet, C. T.; LaGory, K. E.; Environmental Science Division

2009-10-05

Glen Canyon Dam is a hydroelectric facility located on the Colorado River in Arizona that is operated by the U.S. Bureau of Reclamation (Reclamation) for multiple purposes including water storage, flood control, power generation, recreation, and enhancement of fish and wildlife. Glen Canyon Dam operations have been managed for the last several years to improve conditions for the humpback chub (Gila cypha) and other ecosystem components. An extensive amount of literature has been produced on the humpback chub. We developed this annotated bibliography to assist managers and researchers in the Grand Canyon as they perform assessments, refine management strategies, andmore » develop new studies to examine the factors affecting humpback chub. The U.S. Geological Survey recently created a multispecies bibliography (including references on the humpback chub) entitled Bibliography of Native Colorado River Big Fishes (available at www.fort.usgs.gov/Products/data/COFishBib). That bibliography, while quite extensive and broader in scope than ours, is not annotated, and, therefore, does not provide any of the information in the original literature. In developing this annotated bibliography, we have attempted to assemble abstracts from relevant published literature. We present here abstracts taken unmodified from individual reports and articles except where noted. The bibliography spans references from 1976 to 2009 and is organized in five broad topical areas, including: (1) biology, (2) ecology, (3) impacts of dam operations, (4) other impacts, and (5) conservation and management, and includes twenty subcategories. Within each subcategory, we present abstracts alphabetically by author and chronologically by year. We present relevant articles not specific to either the humpback chub or Glen Canyon Dam, but cited in other included reports, under the Supporting Articles subcategory. We provide all citations in alphabetical order in Section 7.« less

Standardized methods for Grand Canyon fisheries research 2015

USGS Publications Warehouse

Persons, William R.; Ward, David L.; Avery, Luke A.

2013-01-01

This document presents protocols and guidelines to persons sampling fishes in the Grand Canyon, to help ensure consistency in fish handling, fish tagging, and data collection among different projects and organizations. Most such research and monitoring projects are conducted under the general umbrella of the Glen Canyon Dam Adaptive Management Program and include studies by the U.S. Geological Survey (USGS), U.S. Fish and Wildlife Service (FWS), National Park Service (NPS), the Arizona Game and Fish Department (AGFD), various universities, and private contractors. This document is intended to provide guidance to fieldworkers regarding protocols that may vary from year to year depending on specific projects and objectives. We also provide herein documentation of standard methods used in the Grand Canyon that can be cited in scientific publications, as well as a summary of changes in protocols since the document was first created in 2002.

Long-term monitoring of sandbars on the Colorado River in Grand Canyon using remote sensing

USGS Publications Warehouse

Ross, Robert P.; Grams, Paul E.

2015-01-01

Closure of Glen Canyon Dam in 1963 dramatically changed discharge and sediment supply to the downstream Colorado River in Marble and Grand Canyons. Magnitudes of seasonal flow variation have been suppressed, while daily fluctuations have increased because of hydropower generation. Lake Powell, the upstream reservoir, traps all sediment, leaving the Paria and Little Colorado Rivers as the main suppliers of fine sediment to the system below Glen Canyon Dam. The reduction in sediment supply, along with changes in discharge, have resulted in finesediment deficit (Topping et al., 2000), leading to a decrease in the size and number of alluvial sandbars (Schmidt and Graf, 1990; Schmidt et al., 2004). However, the understanding of these important spatial and temporal changes in sandbars located along the banks of the river have been limited to infrequent measurements mostly made by direct visitation and topographic surveying (Hazel et al., 2010). Aerial photographs are the only data available from which it is possible to evaluate changes in alluvial deposits at a large number of sites and compare recent conditions with those that existed prior to the initiation of ground-based monitoring in the early 1990s. Previous studies have evaluated the effects of Glen Canyon Dam on sandbars by analysis of comprehensive maps of surficial geology that are based on seven sets of aerial imagery taken between 1935 and 1996 for selected reaches in the first 120 km downstream from Lees Ferry, Arizona (Figure 1). These studies showed that the area of exposed sand in eddy-deposition zones was less in the post-dam period than in the pre-dam period (Leschin and Schmidt, 1995; Schmidt et al., 1999b; Sondossi, 2001, Sondossi and Schmidt, 2001, Schmidt et al., 2004). In this study, we extend these analyses to encompass a 74-year period by including maps of sand deposits visible in aerial imagery taken in 2002, 2005, and 2009 for the same reaches that were mapped in the earlier studies. Results

Monitoring and Evaluation of Yearling Fall Chinook Salmon (Oncorhynchus tshawytscha) Released from Acclimation Facilities Upstream of Lower Granite Dam; 2001 Annual Report.

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

Rocklage, Stephen J.; Kellar, Dale S.

2005-07-01

The Nez Perce Tribe, in cooperation with the U.S. Fish and Wildlife Service and Washington Department of Fish and Wildlife, conducted monitoring and evaluation studies on Lyons Ferry Hatchery reared yearling fall Chinook salmon Oncorhynchus tshawytscha that were acclimated and released at three Fall Chinook Acclimation Project sites upstream of Lower Granite Dam along with yearlings released on-station from Lyons Ferry Hatchery in 2001. This was the sixth year of a long-term project to supplement natural spawning populations of Snake River stock fall Chinook salmon upstream of Lower Granite Dam. The 318,932 yearlings released from the Fall Chinook Acclimation Projectmore » facilities were short of the 450,000 fish quota. We use Passive Integrated Transponder (PIT) tag technology to monitor the primary performance measures of survival to mainstem dams and migration timing. We also monitor size, condition and tag/mark retention at release. We released 7,503 PIT tagged yearlings from Pittsburg Landing, 7,499 from Big Canyon and 2,518 from Captain John Rapids. The Washington Department of Fish and Wildlife released 991 PIT tagged yearlings from Lyons Ferry Hatchery. Fish health sampling indicated that, overall, bacterial kidney disease levels could be considered relatively low. Compared to prior years, Quantitative Health Assessment Indices were relatively low at Big Canyon and Captain John Rapids and about average at Pittsburg Landing and Lyons Ferry Hatchery. Mean fork lengths (95% confidence interval) of the PIT tagged groups ranged from 155.4 mm (154.7-156.1 mm) at Captain John Rapids to 171.6 mm (170.7-172.5 mm) at Lyons Ferry Hatchery. Mean condition factors ranged from 1.02 at Lyons Ferry Hatchery to 1.16 at Big Canyon and Captain John Rapids. Estimated survival (95% confidence interval) of PIT tagged yearlings from release to Lower Granite Dam ranged from 74.4% (73.2-75.5%) for Big Canyon to 85.2% (83.5-87.0%) for Captain John Rapids. Estimated survival from

Geologic map and profiles of the north wall of the Snake River Canyon, Pasadena Valley and Ticeska quadrangles, Idaho

USGS Publications Warehouse

Covington, H.R.; Weaver, Jean N.

1990-01-01

The Snake River Plain is a broad, arcuate region of low relief that extends more than 300 mi across southern Idaho. The Snake River enters the plain near Idaho Falls and flows westward along the southern margin of the eastern Snake River Plain (fig. 1), a position mainly determined by the basaltic lava flows that erupted near the axis of the plain. The highly productive Snake River Plain aquifer north of the Snaked River underlies the most of the eastern plain. The aquifer is composed of basaltic ricks that are interbedded with fluvial and lacustrine sedimentary rocks. The top of the aquifer (water table) is typically less than 500 ft below the land surface, but is deeper than 1,000 ft in few areas. The Snake River had excavated a canyon into the nearly flat-lying basaltic and sedimentary rocks of the eastern Snake River Plain between Milner Dam and King Hill (fig. 2), a distance of almost 90 mi. For much of its length the canyon intersects the Snake River Plain aquifer, which discharges from the north canyon wall as springs of variable size, spacing, and altitude. Geologic controls on springs are of importance because nearly 60 percent of the aquifer's discharge occurs as spring flow along this reach of the canyon. This report is one of several that describes the geologic occurrence of springs along the northern wall of the Snake River canyon from Milner Dam to King Hill. To understand the local geologic controls on springs, the Water Resources Division of the U.S. Geological Survey initiated a geologic mapping project as part of their Snake River Plain Regional Aquifer System-Analysis Program. Objectives of the project were (1) to prepare a geologic map of a strip of land immediately north of the Snake River canyon, (2) to map the geology of the north canyon wall in profile, (3) to locate spring occurrences along the north side of the Snake River between Milner Dam and King Hill, and (4) to estimate spring discharge from the north wall of the canyon.

Assessment of Native Salmonids Above Hells Canyon Dam, Idaho, 2001 Annual Report.

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

Meyer, Kevin A.; Lamansky, Jr., James A.

We investigated factors affecting the distribution and abundance of Yellowstone cutthroat trout (YCT), the abundance of all trout, and species richness in several drainages in the upper Snake River basin in Idaho. A total of 326 randomly selected sites were visited within the four study drainages, and of these, there was sufficient water to inventory fish and habitat in 56 of the sites in the Goose Creek drainage, 64 in the Raft River drainage, 54 in the Blackfoot River drainage, and 27 in the Willow Creek drainage. Fish were captured in 36, 55, 49, and 22 of the sites, respectively,more » and YCT were present at 17, 37, 32, and 13 of the sites, respectively. There was little consistency or strength in the models developed to predict YCT presence/absence and density, trout density, or species richness. Typically, the strongest models had the lowest sample sizes. In the Goose Creek drainage, sites with YCT were higher in elevation and lower in conductivity. In the Raft River drainage, trout cover was more abundant at sites with YCT than without YCT. In the Blackfoot River drainage, there was less fine substrate and more gravel substrate at sites with YCT than at sites without YCT. In the Willow Creek drainage, 70% of the sites located on public land contained YCT, but only 35% of private land contained YCT. The differences in variable importance between drainages suggests that factors that influence the distribution of YCT vary between drainages, and that for the most part the variables we measured had little influence on YCT distribution. n sites containing YCT, average cutthroat trout density was 0.11/m{sup 2}, 0.08/m{sup 2}, 0.10/m{sup 2}, and 0.08/m{sup 2} in the Goose Creek, Raft River, Blackfoot River, and Willow Creek drainages, respectively. In sites containing trout in general, average total trout density in these same drainages was 0.16/m{sup 2}, 0.15/m{sup 2}, 0.10/m{sup 2}, and 0.10/m{sup 2}. Models to predict YCT density, total trout density, and species richness were either weak (i.e., explained little variation) or contained small sample sizes. Based on our results, it appears that factors other than those we measured are affecting fish populations in these drainages.« less

19. Photocopy of a photographca. 1923showing the Anyox Dam in ...

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

19. Photocopy of a photograph--ca. 1923--showing the Anyox Dam in British Columbia, Canada, just prior to completion of final arching. A sudden storm filled the reservoir and water began pouring over the uncompleted arch-ring; the dam was unhurt by the unexpected deluge and Eastwood used this photo as evidence of the great strength of his designs. Courtesy Mr. Charles Allan Whitney.20. DISTANT HELICOPTER VIEW TO SOUTHEAST UP LITTLE ROCK CREEK CANYON, WITH DAM AND RESERVOIR AT RIGHT CENTER. PALMDALE-LITTLEROCK DITCH, MARKED BY DENSE VEGETATION, CROSSES ROAD AT LOWER CENTER. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

Ground-water resources of the Sevier River basin between Yuba Dam and Leamington Canyon, Utah

USGS Publications Warehouse

Bjorklund, Louis Jay; Robinson, Gerald B.

1968-01-01

The area investigated is a segment of the Sevier River basin, Utah, comprising about 900 square miles and including a 19-mile reach of the Sevier River between Yuba Dam and Leamington Canyon. The larger valleys in the area are southern Juab, Round, and Scipio Valleys. The smaller valleys are Mills, Little, Dog, and Tinctic Wash Valleys.The geology of parts of Scipio, Little, and Mills Valleys and parts of the surrounding highlands was mapped and studied to explain the occurrence of numerous sinkholes in the thre valleys and to show their relation to the large springs in Mills Valley. The sinkholes, which are formed in the alluvium, are alined along faults, which penetrate both the alluvium and the underlying bedrock, and they have been formed by collapse of solution cavities in the underlying bedrock. The bedrock is mostly sandy limestone beds of the upper part of the North Horn Formation and of the Flagstaff Limestone. The numerous faults traversing Scipio Valley in a north-northeasterly direction trend directly toward Molter and Blue Springs in Mills Valley. One fault, which can be traced directly between the springs, probably is the principal channelway for the ground water moving from Scipio and Little Valleys to the springs.

Effective mitigation of debris flows at Lemon Dam, La Plata County, Colorado

USGS Publications Warehouse

deWolfe, V.G.; Santi, P.M.; Ey, J.; Gartner, J.E.

2008-01-01

To reduce the hazards from debris flows in drainage basins burned by wildfire, erosion control measures such as construction of check dams, installation of log erosion barriers (LEBs), and spreading of straw mulch and seed are common practice. After the 2002 Missionary Ridge Fire in southwest Colorado, these measures were implemented at Knight Canyon above Lemon Dam to protect the intake structures of the dam from being filled with sediment. Hillslope erosion protection measures included LEBs at concentrations of 220-620/ha (200-600% of typical densities), straw mulch was hand spread at concentrations up to 5.6??metric tons/hectare (125% of typical densities), and seeds were hand spread at 67-84??kg/ha (150% of typical values). The mulch was carefully crimped into the soil to keep it in place. In addition, 13 check dams and 3 debris racks were installed in the main drainage channel of the basin. The technical literature shows that each mitigation method working alone, or improperly constructed or applied, was inconsistent in its ability to reduce erosion and sedimentation. At Lemon Dam, however, these methods were effective in virtually eliminating sedimentation into the reservoir, which can be attributed to a number of factors: the density of application of each mitigation method, the enhancement of methods working in concert, the quality of installation, and rehabilitation of mitigation features to extend their useful life. The check dams effectively trapped the sediment mobilized during rainstorms, and only a few cubic meters of debris traveled downchannel, where it was intercepted by debris racks. Using a debris volume-prediction model developed for use in burned basins in the Western U.S., recorded rainfall events following the Missionary Ridge Fire should have produced a debris flow of approximately 10,000??m3 at Knight Canyon. The mitigation measures, therefore, reduced the debris volume by several orders of magnitude. For comparison, rainstorm

Effective mitigation of debris flows at Lemon Dam, La Plata County, Colorado

NASA Astrophysics Data System (ADS)

deWolfe, Victor G.; Santi, Paul M.; Ey, J.; Gartner, Joseph E.

2008-04-01

To reduce the hazards from debris flows in drainage basins burned by wildfire, erosion control measures such as construction of check dams, installation of log erosion barriers (LEBs), and spreading of straw mulch and seed are common practice. After the 2002 Missionary Ridge Fire in southwest Colorado, these measures were implemented at Knight Canyon above Lemon Dam to protect the intake structures of the dam from being filled with sediment. Hillslope erosion protection measures included LEBs at concentrations of 220-620/ha (200-600% of typical densities), straw mulch was hand spread at concentrations up to 5.6 metric tons/hectare (125% of typical densities), and seeds were hand spread at 67-84 kg/ha (150% of typical values). The mulch was carefully crimped into the soil to keep it in place. In addition, 13 check dams and 3 debris racks were installed in the main drainage channel of the basin. The technical literature shows that each mitigation method working alone, or improperly constructed or applied, was inconsistent in its ability to reduce erosion and sedimentation. At Lemon Dam, however, these methods were effective in virtually eliminating sedimentation into the reservoir, which can be attributed to a number of factors: the density of application of each mitigation method, the enhancement of methods working in concert, the quality of installation, and rehabilitation of mitigation features to extend their useful life. The check dams effectively trapped the sediment mobilized during rainstorms, and only a few cubic meters of debris traveled downchannel, where it was intercepted by debris racks. Using a debris volume-prediction model developed for use in burned basins in the Western U.S., recorded rainfall events following the Missionary Ridge Fire should have produced a debris flow of approximately 10,000 m 3 at Knight Canyon. The mitigation measures, therefore, reduced the debris volume by several orders of magnitude. For comparison, rainstorm-induced debris

Sandbar Response in Marble and Grand Canyons, Arizona, Following the 2008 High-Flow Experiment on the Colorado River

USGS Publications Warehouse

Hazel, Joseph E.; Grams, Paul E.; Schmidt, John C.; Kaplinski, Matt

2010-01-01

A 60-hour release of water at 1,203 cubic meters per second (m3/s) from Glen Canyon Dam in March 2008 provided an opportunity to analyze channel-margin response at discharge levels above the normal, diurnally fluctuating releases for hydropower plant operations. We compare measurements at sandbars and associated campsites along the mainstem Colorado River, downstream from Glen Canyon Dam, at 57 locations in Marble and Grand Canyons. Sandbar and main-channel response to the 2008 high-flow experiment (2008 HFE) was documented by measuring bar and bed topography at the study sites before and after the controlled flood and twice more in the following 6 months to examine the persistence of flood-formed deposits. The 2008 HFE caused widespread deposition at elevations above the stage equivalent to a flow rate of 227 m3/s and caused an increase in the area and volume of the high-elevation parts of sandbars, thereby increasing the size of campsite areas. In this study, we differentiate between four response styles, depending on how sediment was distributed throughout each study site. Then, we present the longitudinal pattern relevant to the different response styles and place the site responses in context with two previous high-release experiments conducted in 1996 and 2004. We find that (1) nearly every measured sandbar aggraded above the 227-m3/s water-surface elevation, resulting in sandbars as large or larger than occurred following previous high flows; (2) reaches closest to Glen Canyon Dam were characterized by a greater percentage of sites that incurred net erosion, although the total sand volume in all sediment-flux monitoring reaches was greater following the 2008 HFE than following previous high flows; and (3) longitudinal differences in topographic response in eddies and in the channel suggest a greater and more evenly distributed sediment supply than existed during previous controlled floods from Glen Canyon Dam.

Colorado River fish monitoring in Grand Canyon, Arizona; 2002–14 humpback chub aggregations

USGS Publications Warehouse

Persons, William R.; Van Haverbeke, David R.; Dodrill, Michael J.

2017-01-31

The humpback chub (Gila cypha) is an endangered cyprinid species endemic to the Colorado River. The largest remaining population of the species spawns and rears in the Little Colorado River in Grand Canyon. Construction and operation of Glen Canyon Dam has altered the main-stem Colorado River in Glen and Grand Canyons. Cold, clear water releases from the dam result in a river that is generally unsuitable for successful humpback chub reproduction. During the early 1990s, nine locations within the main-stem Colorado River were identified as humpback chub aggregations—areas with a consistent and disjunct group of fish with no significant exchange of individuals with other aggregations. We monitored main-stem Colorado River aggregations of humpback chub in Grand Canyon during 2010 to 2014 and compared our results to previous investigations. Relative abundance, as described by catch per unit effort (fish per hour) of adult humpback chub at most main-stem aggregations, generally increased from the 1990s to 2014. In addition, distribution of humpback chub in the main-stem Colorado River has increased since the 1990s. Movement of humpback chub between the Little Colorado River and other aggregations likely adds fish to those aggregations. There is clear evidence of reproduction near the 30-Mile aggregation, and reproduction at Middle Granite Gorge and downstream seems likely based on catches of gravid fish and captures of very young fish, especially during relatively warm water releases from Glen Canyon Dam, 2004 to 2011. Humpback chub relative abundance at Shinumo and Havasu Creek inflows increased following translocations of young humpback chub starting in 2009. In light of this information, we modify the original nine aggregations, combining two previously separate aggregations and dropping two locations to form six distinct aggregations of humpback chub. Trends in humpback chub abundance at main-stem aggregations, relative to management actions (for example

Deciphering Paria and Little Colorado River flood regimes and their significance in multi-objective adaptive management strategies for Colorado River resources in Grand Canyon

NASA Astrophysics Data System (ADS)

Jain, S.; Topping, D. J.; Melis, T. S.

2014-12-01

Planning and decision processes in the Glen Canyon Dam Adaptive Management Program (GCDAMP) strive to balance numerous, often competing, objectives, such as, water supply, hydropower generation, low flow maintenance, sandbars, recreational trout angling, endangered native fish, whitewater rafting, and other sociocultural resources of Glen Canyon National Recreation Area and Grand Canyon National Park. In this context, use of monitored and predictive information on warm-season Paria River floods (JUL-OCT, at point-to-regional scales) has been identified as lead information for a new 10-year long controlled flooding experiment (termed the High-Flow Experiment Protocol) intended to determine management options for rebuilding and maintaining sandbars below Glen Canyon Dam; an adaptive strategy that can potentially facilitate improved planning and dam operations. In this work, we focus on a key concern identified by the GCDAMP, related to the timing and volume of warm season tributary sand input from the Paria River into the Colorado River in Grand Canyon National Park. The Little Colorado River is an important secondary source of sand inputs to Grand Canyon, but its lower segment is also critical spawning habitat for the endangered humpback chub. Fish biologists have reported increased abundance of chub juveniles in this key tributary in summers following cool-season flooding (DEC-FEB), but little is known about chub spawning substrates and behavior or the role that flood frequency in this tributary may play in native fish population dynamics in Grand Canyon. Episodic and intraseasonal variations (with links to equatorial and sub-tropical Pacific sea surface temperature variability) in southwest hydroclimatology are investigated to understand the magnitude, timing and spatial scales of warm- and cool-season floods from these two important tributaries of the semi-arid Colorado Plateau. Coupled variations of floods (magnitude and timing) from these rivers are also

76 FR 24516 - Glen Canyon Dam Adaptive Management Work Group

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-02

... Adaptive Management Program (AMP) was implemented as a result of the Record of Decision on the Operation of... Grand Canyon Protection Act (Pub. L. 102-575) of 1992. The AMP includes a Federal advisory committee... administrative and resource issues pertaining to the AMP. To view a copy of the agenda and documents related to...

77 FR 22801 - Glen Canyon Dam Adaptive Management Work Group

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-17

... Adaptive Management Program (AMP) was implemented as a result of the Record of Decision on the Operation of... Grand Canyon Protection Act (Pub. L. 102-575) of 1992. The AMP includes a Federal advisory committee... related to the above meeting, please visit Reclamation's Web site at: http://www.usbr.gov/uc/rm/amp/amwg...

Geologic map and profiles of the north wall of the Snake River Canyon, Bliss, Hagerman, and Tuttle quadrangles, Idaho

USGS Publications Warehouse

Covington, H.R.; Weaver, Jean N.

1990-01-01

The Snake River Plain is a broad, arcuate region of low relief that extends more than 300 mi across southern Idaho. The Snake River enters the plain near Idaho Falls and flows westward along the southern margin of the eastern Snake River Plain (fig. 1), a position mainly determined by the basaltic lava flows that erupted near the axis of the plain. The highly productive Snake River Plain aquifer north of the Snake River underlies most of the eastern plain. The aquifer is composed of basaltic rocks that are interbedded with fluvial and lacustrine sedimentary rocks. The top of the aquifer (water table) is typically less than 500 ft below the land surface, but is deeper than 1,000 ft in a few areas. The Snake River has excavated a canyon into the nearly flat-lying basaltic and sedimentary rocks of the eastern Snake River Plain between Milner Dam and King Hill (fig. 2), a distance of almost 90 mi. For much of its length the canyon wall as springs of variable size, spacing, and altitude. Geologic controls on springs are of importance because nearly 60 percent of the aquifer's discharge occurs as spring flow along this reach of the canyon. This report is one of several that describes the geologic occurrence of springs along the northern wall of the Snake River canyon from Milner Dam to King Hill (fig. 1). To understand the local geologic controls on springs, the Water Resources Division of the U.S. Geological Survey initiated a geologic mapping project as part of their Snake River Plain Regional Aquifer System-Analysis Program. Objectives of the project were (1) to prepare a geologic map of a strip of land immediately north of the Snake River canyon, (2) to map the geology of the north canyon wall in profile, (3) to locate spring occurrences along the north side of the Snake River between Milner Dam and King Hill, and (4) to estimate spring discharge from the north wall of the canyon.

Topographic change detection at select archeological sites in Grand Canyon National Park, Arizona, 2007–2010

USGS Publications Warehouse

Collins, Brian D.; Corbett, Skye C.; Fairley, Helen C.; Minasian, Diane L.; Kayen, Robert; Dealy, Timothy P.; Bedford, David R.

2012-01-01

Human occupation in Grand Canyon, Arizona, dates from at least 11,000 years before present to the modern era. For most of this period, the only evidence of human occupation in this iconic landscape is provided by archeological sites. Because of the dynamic nature of this environment, many archeological sites are subject to relatively rapid topographic change. Quantifying the extent, magnitude, and cause of such change is important for monitoring and managing these archeological sites. Such quantification is necessary to help inform the continuing debate on whether and how controlled releases from Glen Canyon Dam, located immediately upstream of Grand Canyon National Park, are affecting site erosion rates, artifact transport, and archeological resource preservation along the Colorado River in Grand Canyon. Although long-term topographic change resulting from a variety of natural processes is inherent in the Grand Canyon region, continued erosion of archeological sites threatens both the archeological resources and our future ability to study evidence of past cultural habitation. Thus, this subject is of considerable interest to National Park Service managers and other stakeholders in the Glen Canyon Dam Adaptive Management Program. Understanding the causes and effects of archeological site erosion requires a knowledge of several factors, including the location, timing, and magnitude of the changes occurring in relation to archeological resources, the rates of change, and the relative contribution of potential causes. These potential causes include sediment depletion associated with managed flows from Glen Canyon Dam, site-specific weather and overland flow patterns, visitor impacts, and long-term regional climate change. To obtain this information, highly accurate, spatially specific data are needed from sites undergoing change. Using terrestrial lidar techniques, and building upon three previous surveys of archeological sites performed in 2006 and 2007, we

Monitoring and Evaluation of Yearling Fall Chinook Salmon (Oncorhynchus tshawytscha) Released from Acclimation Facilities Upstream of Lower Granite Dam; 2000 Annual Report.

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

Rocklage, Stephen J.; Kellar, Dale S.

2005-07-01

The Nez Perce Tribe, in cooperation with the U.S. Fish and Wildlife Service and Washington Department of Fish and Wildlife, conducted monitoring and evaluation studies on Lyons Ferry Hatchery reared yearling fall Chinook salmon Oncorhynchus tshawytscha that were acclimated and released at three Fall Chinook Acclimation Project sites upstream of Lower Granite Dam along with yearlings released on-station from Lyons Ferry Hatchery in 2000. This was the fifth year of a long-term project to supplement natural spawning populations of Snake River stock fall Chinook salmon upstream of Lower Granite Dam. The 397,339 yearlings released from the Fall Chinook Acclimation Projectmore » facilities were short of the 450,000 fish quota. We use Passive Integrated Transponder (PIT) tag technology to monitor the primary performance measures of survival to mainstem dams and migration timing. We also monitor size, condition and tag/mark retention at release. We released 7,477 PIT tagged yearlings from Pittsburg Landing, 7,421 from Big Canyon and 2,488 from Captain John Rapids. The Washington Department of Fish and Wildlife released 980 PIT tagged yearlings from Lyons Ferry Hatchery. Fish health sampling indicated that, overall, bacterial kidney disease levels could be considered relatively low. Compared to prior years, Quantitative Health Assessment Indices were relatively low at Big Canyon and Captain John Rapids and about average at Pittsburg Landing and Lyons Ferry Hatchery. Mean fork lengths (95% confidence interval) of the PIT tagged groups ranged from 157.7 mm (157.3-158.1 mm) at Big Canyon to 172.9 mm (172.2-173.6 mm) at Captain John Rapids. Mean condition factors ranged from 1.06 at Captain John Rapids and Lyons Ferry Hatchery to 1.12 at Big Canyon. Estimated survival (95% confidence interval) of PIT tagged yearlings from release to Lower Granite Dam ranged from 87.0% (84.7-89.4%) for Pittsburg Landing to 95.2% (91.5-98.9%) for Captain John Rapids. Estimated survival from

Reconstructing Sediment Supply, Transport and Deposition Behind the Elwha River Dams

NASA Astrophysics Data System (ADS)

Beveridge, C.

2017-12-01

The Elwha River watershed in Olympic National Park of Washington State, USA is predominantly a steep, mountainous landscape where dominant geomorphic processes include landslides, debris flows and gullying. The river is characterized by substantial variability of channel morphology and fluvial processes, and alternates between narrow bedrock canyons and wider alluvial reaches for much of its length. Literature suggests that the Elwha watershed is topographically and tectonically in steady state. The removal of the two massive hydropower dams along the river in 2013 marked the largest dam removal in history. Over the century long lifespan of the dams, approximately 21 million cubic meters of sediment was impounded behind them. Long term erosion rates documented in this region and reservoir sedimentation data give unprecedented opportunities to test watershed sediment yield models and examine dominant processes that control sediment yield over human time scales. In this study, we aim to reconstruct sediment supply, transport and deposition behind the Glines Canyon Dam (most upstream dam) over its lifespan using a watershed modeling approach. We developed alternative models of varying complexity for sediment production and transport at the network scale driven by hydrologic forcing. We simulate sediment supply and transport in tributaries upstream of the dam. The modeled sediment supply and transport dynamics are based on calibrated formulae (e.g., bedload transport is simulated using Wilcock-Crowe 2003 with modification based on observed bedload transport in the Elwha River). Observational data that aid in our approach include DEM, channel morphology, meteorology, and streamflow and sediment (bedload and suspended load) discharge. We aim to demonstrate how the observed sediment yield behind the dams was influenced by upstream transport supply and capacity limitations, thereby demonstrating the scale effects of flow and sediment transport processes in the Elwha River

Quaternary geology and geomorphology of the lower Deschutes River Canyon, Oregon.

Treesearch

Jim E. O' Connor; Janet H. Curran; Robin A. Beebee; Gordon E. Grant; Andrei Sarna-Wojcicki

2003-01-01

The morphology of the Deschutes River canyon downstream of the Pelton-Round Butte dam complex is the product of the regional geologic history, the composition of the geologic units that compose the valley walls, and Quaternary processes and events. Geologic units within the valley walls and regional deformation patterns control overall valley morphology. Valley bottom...

Water temperatures in select nearshore environments of the Colorado River in Grand Canyon, Arizona, during the Low Steady Summer Flow experiment of 2000

USGS Publications Warehouse

Vernieu, William S.; Anderson, Craig R.

2013-01-01

Water releases from Glen Canyon Dam, Arizona, are the primary determinant of streamflow, sediment transport, water quality, and aquatic and riparian habitat availability in the Colorado River downstream of the dam in Grand Canyon. The presence and operation of the dam have transformed the seasonally warm Colorado River into a consistently cold river because of hypolimnetic, or deep-water, releases from the penstock withdrawal structures on the dam. These releases have substantially altered the thermal regime of the downstream riverine environment. This, in turn, has affected the biota of the river corridor, particularly native and nonnative fish communities and the aquatic food web. In the spring and summer of 2000, a Low Steady Summer Flow experiment was conducted by the U.S. Geological Survey and the Bureau of Reclamation to evaluate the effects of the experimental flow on physical and biological resources of the Colorado River ecosystem downstream from Glen Canyon Dam to Lake Mead on the Arizona-Nevada border. This report describes the water temperatures collected during the experimental flow from 14 nearshore sites in the river corridor in Grand Canyon to assess the effects of steady releases on the thermal dynamics of nearshore environments. These nearshore areas are characterized by low-velocity flows with some degree of isolation from the higher velocity flows in the main channel and are hypothesized to be important rearing environments for young native fish. Water-temperature measurements were made at 14 sites, ranging from backwater to open-channel environments. Warming during daylight hours, relative to main-channel temperatures, was measured at all sites in relation to the amount of isolation from the main-channel current. Boat traffic, amount of direct solar radiation, and degree of isolation from the main-channel current appear to be the primary factors affecting the differential warming of the nearshore environment.

Monitoring and Evaluation of Yearling Fall Chinook Salmon Released from Acclimation Facilities Upstream of Lower Granite Dam; 1998 Annual Report.

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

Rocklage, Stephen J.

The Nez Perce Tribe, in cooperation with the U.S. Fish and Wildlife Service and Washington Department of Fish and Wildlife, conducted monitoring and evaluation studies on Lyons Ferry Hatchery (Snake River stock) yearling fall chinook salmon that were acclimated and released at three Fall Chinook Acclimation Project sites upstream of Lower Granite Dam along with yearlings released on-station from Lyons Ferry Hatchery in 1998. The three fall chinook acclimation facilities are operated by the Nez Perce Tribe and located at Pittsburg Landing and Captain John Rapids on the Snake River and at Big Canyon Creek on the Clearwater River. Yearlingsmore » at the Big Canyon facility consisted of two size classes that are referred to in this report as 9.5 fish per pound (fpp) and 30 fpp. The Big Canyon 9.5 fpp were comparable to the yearlings at Pittsburg Landing, Captain John Rapids and Lyons Ferry Hatchery. A total of 9,942 yearlings were PIT tagged and released at Pittsburg Landing. PIT tagged yearlings had a mean fork length of 159.9 mm and mean condition factor of 1.19. Of the 9,942 PIT tagged fish released, a total of 6,836 unique tags were detected at mainstem Snake and Columbia River dams (Lower Granite, Little Goose, Lower Monumental and McNary). A total of 4,926 9.5 fpp and 2,532 30 fpp yearlings were PIT tagged and released at Big Canyon. PIT tagged 9.5 fpp yearlings had a mean fork length of 156.9 mm and mean condition factor of 1.13. PIT tagged 30 fpp yearlings had a mean fork length of 113.1 mm and mean condition factor of 1.18. Of the 4,926 PIT tagged 9.5 fpp yearlings released, a total of 3,042 unique tags were detected at mainstem Snake and Columbia River dams. Of the 2,532 PIT tagged 30 fpp yearlings released, a total of 1,130 unique tags were detected at mainstem Snake and Columbia River dams. A total of 1,253 yearlings were PIT tagged and released at Captain John Rapids. PIT tagged yearlings had a mean fork length of 147.5 mm and mean condition factor of 1

Nearshore temperature findings for the Colorado River in Grand Canyon, Arizona: possible implications for native fish

USGS Publications Warehouse

Ross, Robert P.; Vernieu, William S.

2013-01-01

Since the completion of Glen Canyon Dam, Arizona, in 1963, downstream water temperatures in the main channel of the Colorado River in Glen, Marble, and Grand Canyons are much colder in summer. This has negatively affected humpback chub (Gila cypha) and other native fish adapted to seasonally warm water, reducing main-channel spawning activity and impeding the growth and development of larval and juvenile fish. Recently published studies by U.S. Geological Survey scientists found that under certain conditions some isolated nearshore environments in Grand Canyon allow water to become separated from the main-channel current and to warm, providing refuge areas for the development of larval and juvenile fish.

Effects of Glen Canyon Dam discharges on water velocity and temperatures at the confluence of the Colorado and Little Colorado Rivers and implications for habitat for young-of-year humpback chub (Gila cypha-

USGS Publications Warehouse

Protiva, Frank R.; Ralston, Barbara E.; Stone, Dennis M.; Kohl, Keith A.; Yard, Michael D.; Haden, G. Allen

2010-01-01

Water velocity and temperature are physical variables that affect the growth and survivorship of young-of-year (YOY) fishes. The Little Colorado River, a tributary to the Colorado River in Grand Canyon, is an important spawning ground and warmwater refuge for the endangered humpback chub (Gila cypha) from the colder mainstem Colorado River that is regulated by Glen Canyon Dam. The confluence area of the Little Colorado River and the Colorado River is a site where YOY humpback chub (size 30-90 mm) emerging from the Little Colorado River experience both colder temperatures and higher velocities associated with higher mainstem discharge. We used detailed surveying and mapping techniques in combination with YOY velocity and temperature preferenda (determined from field and lab studies) to compare the areal extent of available habitat for young fishes at the confluence area under four mainstem discharges (227, 368, 504, and 878 m3/s). Comparisons revealed that the areal extent of low-velocity, warm water at the confluence decreased when discharges exceeded 368 m3/s. Furthermore, mainstem fluctuations, depending on the rate of upramp, can affect velocity and temperature dynamics in the confluence area within several hours. The amount of daily fluctuations in discharge can result in the loss of approximately 1.8 hectares of habitat favorable to YOY humpback chub. Consequently, flow fluctuations and the accompanying changes in velocity and temperature at the confluence may diminish the recruitment potential of humpback chub that spawn in the tributary stream. This study illustrates the utility of multiple georeferenced data sources to provide critical information related to the influence of the timing and magnitude of discharge from Glen Canyon Dam on potential rearing environment at the confluence area of the Little Colorado River.

Elwha River dam removal-Rebirth of a river

USGS Publications Warehouse

Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

After years of planning for the largest project of its kind, the Department of the Interior will begin removal of two dams on the Elwha River, Washington, in September 2011. For nearly 100 years, the Elwha and Glines Canyon Dams have disrupted natural processes, trapping sediment in the reservoirs and blocking fish migrations, which changed the ecology of the river downstream of the dams. All five Pacific salmon species and steelhead-historically present in large numbers-are locally extirpated or persist in critically low numbers. Upstream of the dams, more than 145 kilometers of pristine habitat, protected inside Olympic National Park, awaits the return of salmon populations. As the dams are removed during a 2-3 year project, some of the 19 million cubic meters of entrapped sediment will be carried downstream by the river in the largest controlled release of sediment into a river and marine waters in history. Understanding the changes to the river and coastal habitats, the fate of sediments, and the salmon recolonization of the Elwha River wilderness will provide useful information for society as future dam removals are considered.

Geologic map and profile of the north wall of the Snake River Canyon, Eden, Murtaugh, Milner Butte, and Milner quadrangles, Idaho

USGS Publications Warehouse

Covington, H.R.; Weaver, Jean N.

1990-01-01

The Snake River Plain is a broad, arcuate region of low relief that extends more than 300 mi across southern Idaho. The Snake River enters the plain near Idaho Falls and flows westward along the southern margin of the eastern Snake River Plain (fig 1), a position mainly determined by the basaltic lava flows that erupted near the axis of the plain. The highly productive Snake River Plain aquifer (water table) is typically less than 500 ft below the land surface, but us deeper than 1,000 ft in a few areas. The Snake River has excavated a canyon into the nearly flat lying basaltic and sedimentary rocks of the  eastern Snake River Plain between Milner Dam and King Hill (fig. 2), a distance of almost 90 mi. For much of its length the canyon intersects the Snake River Plain aquifer, which discharges form the northern canyon wall as springs of variable size, spacing and altitude. Geologic controls on wprings are of importance because nearly 60 percent of the aquifer's discharge occurs as spring flow along this reach of the canyon. This report is one of the several that describes the geologic occurrence of the springs along the northern wall of the Snake River canyone from Milner Dam to King Hill. 

Impact of debris dams on hyporheic interaction along a semi-arid stream

NASA Astrophysics Data System (ADS)

Lautz, Laura K.; Siegel, Donald I.; Bauer, Robert L.

2006-01-01

Hyporheic exchange increases the potential for solute retention in streams by slowing downstream transport and increasing solute contact with the substrate. Hyporheic exchange may be a major mechanism to remove nutrients in semi-arid watersheds, where livestock have damaged stream riparian zones and contributed nutrients to stream channels. Debris dams, such as beaver dams and anthropogenic log dams, may increase hyporheic interactions by slowing stream water velocity, increasing flow complexity and diverting water to the subsurface.Here, we report the results of chloride tracer injection experiments done to evaluate hyporheic interaction along a 320 m reach of Red Canyon Creek, a second order stream in the semi-arid Wind River Range of Wyoming. The study site is part of a rangeland watershed managed by The Nature Conservancy of Wyoming, and used as a hydrologic field site by the University of Missouri Branson Geologic Field Station. The creek reach we investigated has debris dams and tight meanders that hypothetically should enhance hyporheic interaction. Breakthrough curves of chloride measured during the field experiment were modelled with OTIS-P, a one-dimensional, surface-water, solute-transport model from which we extracted the storage exchange rate and cross-sectional area of the storage zone As for hyporheic exchange. Along gaining reaches of the stream reach, short-term hyporheic interactions associated with debris dams were comparable to those associated with severe meanders. In contrast, along the non-gaining reach, stream water was diverted to the subsurface by debris dams and captured by large-scale near-stream flow paths. Overall, hyporheic exchange rates along Red Canyon Creek during snowmelt recession equal or exceed exchange rates observed during baseflow at other streams.

Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA.

PubMed

Walters, David M; Rosi-Marshall, Emma; Kennedy, Theodore A; Cross, Wyatt F; Baxter, Colden V

2015-10-01

Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17-1.59 μg g(-1) Hg and 1.35-2.65 μg g(-1) Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ(15) N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6-100% and 56-100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries. © 2015 SETAC.

HELLS HOLE ROADLESS AREA, ARIZONA AND NEW MEXICO.

USGS Publications Warehouse

Ratte, James C.; Briggs, John P.

1984-01-01

The Hells Hole Roadless Area encompasses about 50 sq mi along the Arizona-New Mexico State line. The area was studied and the southeastern part was determined to have a probable mineral-resource potential for the discovery of base- or precious-metal deposits related to igneous intrusions of middle to late Tertiary age. There also is a probable resource potential for porphyry copper mineralization of Laramide age beneath the Tertiary volcanic rocks that cover the area. There is little promise for the occurrence of energy resources in the area. Additional geochemical and petrological studies of the rocks of the Hells Hole volcanic center and modeling of geophysical anomalies are necessary to adequately appraise the mineral-resource potential of the area.

Owyhee River intracanyon lava flows: does the river give a dam?

USGS Publications Warehouse

Ely, Lisa L.; Brossy, Cooper C.; House, P. Kyle; Safran, Elizabeth B.; O'Connor, Jim E.; Champion, Duane E.; Fenton, Cassandra R.; Bondre, Ninad R.; Orem, Caitlin A.; Grant, Gordon E.; Henry, Christopher D.; Turrin, Brent D.

2013-01-01

Rivers carved into uplifted plateaus are commonly disrupted by discrete events from the surrounding landscape, such as lava flows or large mass movements. These disruptions are independent of slope, basin area, or channel discharge, and can dominate aspects of valley morphology and channel behavior for many kilometers. We document and assess the effects of one type of disruptive event, lava dams, on river valley morphology and incision rates at a variety of time scales, using examples from the Owyhee River in southeastern Oregon. Six sets of basaltic lava flows entered and dammed the river canyon during two periods in the late Cenozoic ca. 2 Ma–780 ka and 250–70 ka. The dams are strongly asymmetric, with steep, blunt escarpments facing up valley and long, low slopes down valley. None of the dams shows evidence of catastrophic failure; all blocked the river and diverted water over or around the dam crest. The net effect of the dams was therefore to inhibit rather than promote incision. Once incision resumed, most of the intracanyon flows were incised relatively rapidly and therefore did not exert a lasting impact on the river valley profile over time scales >106 yr. The net long-term incision rate from the time of the oldest documented lava dam, the Bogus Rim lava dam (≤1.7 Ma), to present was 0.18 mm/yr, but incision rates through or around individual lava dams were up to an order of magnitude greater. At least three lava dams (Bogus Rim, Saddle Butte, and West Crater) show evidence that incision initiated only after the impounded lakes filled completely with sediment and there was gravel transport across the dams. The most recent lava dam, formed by the West Crater lava flow around 70 ka, persisted for at least 25 k.y. before incision began, and the dam was largely removed within another 35 k.y. The time scale over which the lava dams inhibit incision is therefore directly affected by both the volume of lava forming the dam and the time required for sediment

76 FR 584 - Glen Canyon Dam Adaptive Management Program Work Group (AMWG)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-05

... 2010 expenditures, (2) updates on High Flow Experimental Protocol and the Non-native Fish Control... Group (AMWG) AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of public meeting. SUMMARY: The... committee, the Adaptive Management Work Group (AMWG), a technical work group (TWG), a Grand Canyon...

Effects of High-Flow Experiments from Glen Canyon Dam on Abundance, Growth, and Survival Rates of Early Life Stages of Rainbow Trout in the Lees Ferry Reach of the Colorado River

USGS Publications Warehouse

Korman, Josh; Kaplinski, Matthew; Melis, Theodore S.

2010-01-01

High-flow experiments (HFEs) from Glen Canyon Dam are primarily intended to conserve fine sediment and improve habitat conditions for native fish in the Colorado River as it flows through Grand Canyon National Park, Arizona. These experimental flows also have the potential to affect the rainbow trout (Oncorhynchus mykiss) population in the Lees Ferry tailwater reach immediately below the dam, which supports a highly valued recreational fishery and likely influences the abundance of rainbow trout in Grand Canyon. Understanding how flow regimes affect the survival and growth of juvenile rainbow trout is critical to interpreting trends in adult abundance. This study reports on the effects of HFEs in 2004 and 2008 on early life stages of rainbow trout in the Lees Ferry reach on the basis of monthly sampling of redds (egg nests) and the abundance of the age-0 trout (fertilization to about 1 to 2 months from emergence) and their growth during a 7-year period between 2003 and 2009. Multiple lines of evidence indicate that the March 2008 HFE resulted in a large increase in early survival rates of age-0 trout because of an improvement in habitat conditions. A stock-recruitment analysis demonstrated that age-0 abundance in July 2008 was more than fourfold higher than expected, given the number of viable eggs that produced these fish. A hatch-date analysis showed that early survival rates were much higher for cohorts that hatched about 1 month after the 2008 HFE (about April 15, 2008) relative to those fish that hatched before this date. These cohorts, fertilized after the 2008 HFE, would have emerged into a benthic invertebrate community that had recovered, and was possibly enhanced by, the HFE. Interannual differences in growth of age-0 trout, determined on the basis of otolith microstructure, support this hypothesis. Growth rates in the summer and fall of 2008 (0.44 mm/day) were virtually the same as in 2006 (0.46 mm/day), the highest recorded during 6 years, even though

Design of a sediment-monitoring gaging network on ephemeral tributaries of the Colorado River in Glen, Marble, and Grand Canyons, Arizona

USGS Publications Warehouse

Griffiths, Ronald E.; Topping, David J.; Anderson, Robert S.; Hancock, Gregory S.; Melis, Theodore S.

2014-01-01

Management of sediment in rivers downstream from dams requires knowledge of both the sediment supply and downstream sediment transport. In some dam-regulated rivers, the amount of sediment supplied by easily measured major tributaries may overwhelm the amount of sediment supplied by the more difficult to measure lesser tributaries. In this first class of rivers, managers need only know the amount of sediment supplied by these major tributaries. However, in other regulated rivers, the cumulative amount of sediment supplied by the lesser tributaries may approach the total supplied by the major tributaries. The Colorado River downstream from Glen Canyon has been hypothesized to be one such river. If this is correct, then management of sediment in the Colorado River in the part of Glen Canyon National Recreation Area downstream from the dam and in Grand Canyon National Park may require knowledge of the sediment supply from all tributaries. Although two major tributaries, the Paria and Little Colorado Rivers, are well documented as the largest two suppliers of sediment to the Colorado River downstream from Glen Canyon Dam, the contributions of sediment supplied by the ephemeral lesser tributaries of the Colorado River in the lowermost Glen Canyon, and Marble and Grand Canyons are much less constrained. Previous studies have estimated amounts of sediment supplied by these tributaries ranging from very little to almost as much as the amount supplied by the Paria River. Because none of these previous studies relied on direct measurement of sediment transport in any of the ephemeral tributaries in Glen, Marble, or Grand Canyons, there may be significant errors in the magnitudes of sediment supplies estimated during these studies. To reduce the uncertainty in the sediment supply by better constraining the sediment yield of the ephemeral lesser tributaries, the U.S. Geological Survey Grand Canyon Monitoring and Research Center established eight sediment-monitoring gaging

Geologic Hazards Associated With a Proposed Dam on the Yarlung-Tsangpo River in SE Tibet

NASA Astrophysics Data System (ADS)

Zeitler, P. K.; Meltzer, A. S.; Hallet, B.; Kidd, W. S.; Koons, P. O.

2007-12-01

For a decade anecdotes and media reports have been circulating about a proposed dam on the Yarlung- Tsangpo River in SE Tibet. The proposed site is in the deep canyon of the Yarlung-Tsangpo where the river leaves the Tibetan Plateau across an immense knickpoint, falling ~2000 m along an irregular U-shaped reach ~100 km in length. The fundamental purpose of the dam is generation of ~40,000 MW of hydropower, to be used in diverting a portion of the impounded river to water-starved regions of northern China. Offsetting benefits that would accrue from improved water supply in the north, debate has centered on the water-flow and sediment-flux impacts that would be felt downstream in the Brahmaputra system in northeastern India and Bangladesh, as well as the impact of a dam and large lake on the pristine, ecologically and ethnographically diverse area around the Yarlung-Tsangpo canyon, an area of great significance to Tibetan Buddhists. We have been examining the geodynamic evolution of eastern Tibet, and have gathered considerable geophysical and geological data on the knickpoint region. The knickpoint traverses the Namche Barwa-Gyala Peri massif, one of the most geologically active regions on Earth. In this region, very rapid bedrock exhumation at rates of 7 mm/yr or more has exposed granites as young as 1 Ma, and these rates have been ongoing for at least the past 3 m.y. Detrital-dating evidence shows that these high rates continue at present and that erosion within the massif contributes fully 50% of the suspended-sediment load in the Yarlung-Tsangpo at the point where it enters the Brahmaputra (this would be about 100 Mt/yr derived from the massif). The steep slopes in the massif fail by pervasive landsliding and suggest a steady-state topography where the high erosion rates are balanced by equivalent rates of rock uplift accommodated by numerous active structures. At a more regional scale, GPS results show that steep three-dimensional velocity gradients exist

An ATPase-deficient variant of the SNF2 family member HELLS shows altered dynamics at pericentromeric heterochromatin.

PubMed

Lungu, Cristiana; Muegge, Kathrin; Jeltsch, Albert; Jurkowska, Renata Z

2015-05-22

The HELLS (helicase, lymphoid specific, also known as lymphoid-specific helicase) protein is related to the SNF2 (sucrose non-fermentable 2) family of chromatin remodeling ATPases. It is required for efficient DNA methylation in mammals, particularly at heterochromatin-located repetitive sequences. In this study, we investigated the interaction of HELLS with chromatin and used an ATPase-deficient HELLS variant to address the role of ATP hydrolysis in this process. Chromatin fractionation experiments demonstrated that, in the absence of the ATPase activity, HELLS is retained at the nuclear matrix compartment, defined in part by lamin B1. Microscopy studies revealed a stronger association of the ATPase-deficient mutant with heterochromatin. These results were further supported by fluorescence recovery after photobleaching measurements, which showed that, at heterochromatic sites, wild-type HELLS is very dynamic, with a recovery half-time of 0.8s and a mobile protein fraction of 61%. In contrast, the ATPase-deficient mutant displayed 4.5-s recovery half-time and a reduction in the mobile fraction to 30%. We also present evidence suggesting that, in addition to the ATPase activity, a functional H3K9me3 signaling pathway contributes to an efficient release of HELLS from pericentromeric chromatin. Overall, our results show that a functional ATPase activity is not required for the recruitment of HELLS to heterochromatin, but it is important for the release of the enzyme from these sites. Copyright © 2015 Elsevier Ltd. All rights reserved.

Financial analysis of experimental releases conducted at Glen Canyon Dam during water years 1997 through 2005.

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

Veselka, T. D.; Poch, L. A.; Palmer, C. S.

2010-04-21

Because of concerns about the impact that Glen Canyon Dam (GCD) operations were having on downstream ecosystems and endangered species, the Bureau of Reclamation (Reclamation) conducted an Environmental Impact Statement (EIS) on dam operations (DOE 1996). New operating rules and management goals for GCD that had been specified in the Record of Decision (ROD) (Reclamation 1996) were adopted in February 1997. In addition to issuing new operating criteria, the ROD mandated experimental releases for the purpose of conducting scientific studies. This paper examines the financial implications of the experimental flows that were conducted at the GCD from 1997 to 2005.more » An experimental release may have either a positive or negative impact on the financial value of energy production. This study estimates the financial costs of experimental releases, identifies the main factors that contribute to these costs, and compares the interdependencies among these factors. An integrated set of tools was used to compute the financial impacts of the experimental releases by simulating the operation of the GCD under two scenarios, namely, (1) a baseline scenario that assumes operations comply with the ROD operating criteria and experimental releases that actually took place during the study period, and (2) a ''without experiments'' scenario that is identical to the baseline scenario of operations that comply with the GCD ROD, except it assumes that experimental releases did not occur. The Generation and Transmission Maximization (GTMax) model was the main simulation tool used to dispatch GCD and other hydropower plants that comprise the Salt Lake City Area Integrated Projects (SLCA/IP). Extensive data sets and historical information on SLCA/IP power plant characteristics, hydrologic conditions, and Western Area Power Administration's (Western's) power purchase prices were used for the simulation. In addition to estimating the financial impact of experimental releases, the GTMax

Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA

USGS Publications Warehouse

Walters, David M.; E.J. Rosi-Marshall,; Kennedy, Theodore A.; W.F. Cross,; C.V. Baxter,

2015-01-01

Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17–1.59 μg g–1 Hg and 1.35–2.65 μg g–1 Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ15N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6–100% and 56–100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries. Environ Toxicol Chem2015;9999:1–10

Monitoring and Evaluation of Yearling Fall Chinook Salmon (Oncorhynchus tshawytscha) Released from Acclimation Facilities Upstream of Lower Granite Dam; 2003 Annual Report.

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

Rocklage, Stephen J.

The Nez Perce Tribe, in cooperation with the U.S. Fish and Wildlife Service and Washington Department of Fish and Wildlife, conducted monitoring and evaluation studies on Lyons Ferry Hatchery reared yearling fall Chinook salmon Oncorhynchus tshawytscha that were acclimated and released at three Fall Chinook Acclimation Project (FCAP) sites upstream of Lower Granite Dam in 2003. This was the eighth year of a long-term project to supplement natural spawning populations of Snake River stock fall Chinook salmon upstream of Lower Granite Dam. The 437,633 yearlings released from the Fall Chinook Acclimation Project facilities were short of the 450,000 fish quota.more » We use Passive Integrated Transponder (PIT) tag technology to monitor the primary performance measures of survival to mainstem dams and migration timing. We also monitor size, condition and tag/mark retention at release. We released 7,492 PIT tagged yearlings from Pittsburg Landing, 7,494 from Big Canyon and 2,497 from Captain John Rapids. Fish health sampling indicated that, overall, bacterial kidney disease levels at the acclimation facilities could be considered medium with 37-83% of the fish sampled rating medium to very high. Mean fork lengths (95% confidence interval) of the PIT tagged groups ranged from 153.7 mm (153.2-154.2 mm) at Captain John Rapids to 164.2 mm (163.9-164.5 mm) at Pittsburg Landing. Mean condition factors ranged from 1.06 at Lyons Ferry Hatchery to 1.22 at Captain John Rapids. Estimated survival (95% confidence interval) of PIT tagged yearlings from release to Lower Granite Dam ranged from 83.1% (80.7-85.5%) for Big Canyon to 91.7% (87.7-95.7%) for Captain John Rapids. Estimated survival from release to McNary Dam ranged from 59.9% (54.6-65.2%) for Big Canyon to 69.4% (60.5-78.4%) for Captain John Rapids. Median migration rates to Lower Granite Dam, based on all observations of PIT tagged yearlings from the FCAP facilities, ranged from 5.8 river kilometers per day (rkm/d) for

Topographic Change Detection at Select Archeological Sites in Grand Canyon National Park, Arizona, 2006-2007

USGS Publications Warehouse

Collins, Brian D.; Minasian, Diane L.; Kayen, Robert

2009-01-01

Topographic change of archeological sites within the Colorado River corridor of Grand Canyon National Park (GCNP) is a subject of interest to National Park Service managers and other stakeholders in the Glen Canyon Dam Adaptive Management Program. Although long-term topographic change resulting from a variety of natural processes is typical in the Grand Canyon region, a continuing debate exists on whether and how controlled releases from Glen Canyon Dam, located immediately upstream of GCNP, are impacting rates of site erosion, artifact transport, and the preservation of archeological resources. Continued erosion of archeological sites threatens both the archeological resources and our future ability to study evidence of past cultural habitation. Understanding the causes and effects of archaeological site erosion requires a knowledge of several factors including the location and magnitude of the changes occurring in relation to archeological resources, the rate of the changes, and the relative contribution of several potential causes, including sediment depletion associated with managed flows from Glen Canyon Dam, site-specific weather patterns, visitor impacts, and long-term climate change. To obtain this information, highly accurate, spatially specific data are needed from sites undergoing change. Using terrestrial lidar data collection techniques and novel TIN- and GRID-based change-detection post-processing methods, we analyzed topographic data for nine archeological sites. The data were collected using three separate data collection efforts spanning 16 months (May 2006 to September 2007). Our results documented positive evidence of erosion, deposition, or both at six of the nine sites investigated during this time interval. In addition, we observed possible signs of change at two of the other sites. Erosion was concentrated in established gully drainages and averaged 12 cm to 17 cm in depth with maximum depths of 50 cm. Deposition was concentrated at specific

Debris flows in Grand Canyon National Park, Arizona: magnitude, frequency and effects on the Colorado River

USGS Publications Warehouse

Melis, Theodre S.; Webb, Robert H.; ,

1993-01-01

Debris flows are recurrent sediment-transport processes in 525 tributaries of the Colorado River in Grand Canyon. Arizona. Initiated by slope failures in bedrock and (or) colluvium during intense rainfall, Grand Canyon debris flows are high-magnitude, short-duration floods. Debris flows in these tributaries transport very large boulders into the river where they accumulate on debris fans and form rapids. The frequency of debris flows range from less than 1 per century to 10 or more per century in these tributaries. Before regulation by Glen Canyon Dam in 1963, high-magnitude floods on the Colorado River reworked debris fans by eroding all particles except large boulders. Because flow regulation has substantially decreased the river's competence, debris flows occurring after 1963 have increased accumulation of finer-grained sediments on debris fans and in rapids.

Erosional threshold for the formation of bedrock canyons carved by megafloods on Earth and Mars

NASA Astrophysics Data System (ADS)

Lamb, Michael P.; Lapotre, Mathieu G. A.; Larsen, Isaac J.; Williams, Rebecca M. E.

2017-04-01

Enormous canyons have been carved into the surfaces of Earth and Mars by catastrophic outbursts of water. On Mars, these bedrock canyons, known as the planetary-scale outflow channels, are the most important indicator of large volumes of flowing water in the planet's history. Despite their importance and now decades of observations of canyon morphology, we lack a basic understanding of how the canyons formed, which limits our ability to reconstruct flood discharge, duration, and water volume. In this presentation I will summarize recent work - using mechanistic numerical models and field observations of similar landforms on Earth - that suggests that bedrock canyons carved by megafloods may rapidly evolve to a size and shape in which boundary shear stress just exceeds that required to entrain fractured blocks of rock. Recent advances in theory for plucking, sliding and toppling of fractured rock allow for quantitative constraints on erosion thresholds. Coupling these erosional constraints with 2-D hydrodynamic models at waterfalls shows that cataracts in basalt, which are common in megaflood terrain, evolve to a threshold state such that canyon width accurately reflects flood discharge. The erosional threshold hypothesis also is consistent with the formation of gravel bars in the Channeled Scablands of the Missoula Floods, USA, and with observations of a small flood-carved canyon from a dam overflow event in 2002 in Texas. Together, these studies suggest that canyons progressively erode in concert with megaflooding, such that flood waters never fully filled the final canyon relief, implying smaller flood discharges and longer durations than models that assume near canyon-filling floods routed over modern topography.

Magnitude and frequency data for historic debris flows in Grand Canyon National Park and vicinity, Arizona

USGS Publications Warehouse

Melis, T.S.; Webb, R.H.; Griffiths, P.G.; Wise, T.J.

1995-01-01

Debris flows occur in 529 tributaries of the Colorado River in Grand Canyon between Lees Ferry and Diamond Creek, Arizona (river miles 0 to 225). An episodic type of flash flood, debris flows transport poorly-sorted sediment ranging in size from clay to boulders into the Colorado River. Debris flows create and maintain debris fans and the hundreds of associated riffles and rapids that control the geomorphic framework of the Colorado River downstream from Glen Canyon Dam. Between 1984 and 1994, debris flows created 4 new rapids and enlarged 17 existing rapids and riffles. Debris flows in Grand Canyon are initiated by slope failures that occur during intense rainfall. Three of these mechanisms of slope failure are documented. Failures in weathered bedrock, particularly in the Hermit Shale and Supai Group, have initiated many historic debris flows in Grand Canyon. A second mechanism, termed the fire-hose effect, occurs when runoff pours over cliffs onto unconsolidated colluvial wedges, triggering a failure. A third initiation mechanism occurs when intense precipitation causes failures in colluvium overlying bedrock. Multiple source areas and extreme topographic relief in Grand Canyon commonly result in combinations of these three initiation mechanisms. Interpretation of 1,107 historical photographs spanning 120 years, supplemented with aerial photography made between 1935 and 1994, yielded information on the frequency of debris flows in 168 of the 529 tributaries (32 percent) of the Colorado River in Grand Canyon. Of the 168 tributaries, 96 contain evidence of debris flows that have occurred since 1872, whereas 72 tributaries have not had a debris flow during the last century. The oldest debris flow we have documented in Grand Canyon occurred 5,400 years ago in an unnamed tributary at river mile 63.3-R. Our results indicate that the frequency of debris flows ranges from one every 10 to 15 years in certain eastern tributaries, to less than one per century in other

Airborne digital-image data for monitoring the Colorado River corridor below Glen Canyon Dam, Arizona, 2009 - Image-mosaic production and comparison with 2002 and 2005 image mosaics

USGS Publications Warehouse

Davis, Philip A.

2012-01-01

Airborne digital-image data were collected for the Arizona part of the Colorado River ecosystem below Glen Canyon Dam in 2009. These four-band image data are similar in wavelength band (blue, green, red, and near infrared) and spatial resolution (20 centimeters) to image collections of the river corridor in 2002 and 2005. These periodic image collections are used by the Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Survey to monitor the effects of Glen Canyon Dam operations on the downstream ecosystem. The 2009 collection used the latest model of the Leica ADS40 airborne digital sensor (the SH52), which uses a single optic for all four bands and collects and stores band radiance in 12-bits, unlike the image sensors that GCMRC used in 2002 and 2005. This study examined the performance of the SH52 sensor, on the basis of the collected image data, and determined that the SH52 sensor provided superior data relative to the previously employed sensors (that is, an early ADS40 model and Zeiss Imaging's Digital Mapping Camera) in terms of band-image registration, dynamic range, saturation, linearity to ground reflectance, and noise level. The 2009 image data were provided as orthorectified segments of each flightline to constrain the size of the image files; each river segment was covered by 5 to 6 overlapping, linear flightlines. Most flightline images for each river segment had some surface-smear defects and some river segments had cloud shadows, but these two conditions did not generally coincide in the majority of the overlapping flightlines for a particular river segment. Therefore, the final image mosaic for the 450-kilometer (km)-long river corridor required careful selection and editing of numerous flightline segments (a total of 513 segments, each 3.2 km long) to minimize surface defects and cloud shadows. The final image mosaic has a total of only 3 km of surface defects. The final image mosaic for the western end of the corridor has

Revised financial analysis of experimental releases conducted at Glen Canyon Dam during water years 1997 through 2005.

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

Veselka, T. D.; Poch, L. A.; Palmer, C. S.

2011-01-11

Because of concerns about the impact that Glen Canyon Dam (GCD) operations were having on downstream ecosystems and endangered species, the Bureau of Reclamation (Reclamation) conducted an Environmental Impact Statement (EIS) on dam operations (DOE 1996). New operating rules and management goals for GCD that had been specified in the Record of Decision (ROD) (Reclamation 1996) were adopted in February 1997. In addition to issuing new operating criteria, the ROD mandated experimental releases for the purpose of conducting scientific studies. This paper examines the financial implications of the experimental flows that were conducted at the GCD from 1997 to 2005.more » An experimental release may have either a positive or negative impact on the financial value of energy production. This study estimates the financial costs of experimental releases, identifies the main factors that contribute to these costs, and compares the interdependencies among these factors. An integrated set of tools was used to compute the financial impacts of the experimental releases by simulating the operation of the GCD under two scenarios, namely, (1) a baseline scenario that assumes operations comply with the ROD operating criteria and experimental releases that actually took place during the study period, and (2) a 'without experiments' scenario that is identical to the baseline scenario of operations that comply with the GCD ROD, except it assumes that experimental releases did not occur. The Generation and Transmission Maximization (GTMax) model was the main simulation tool used to dispatch GCD and other hydropower plants that comprise the Salt Lake City Area Integrated Projects (SLCA/IP). Extensive data sets and historical information on SLCA/IP power plant characteristics, hydrologic conditions, and Western Area Power Administration's (Western's) power purchase prices were used for the simulation. In addition to estimating the financial impact of experimental releases, the GTMax

Financial analysis of experimental releases conducted at Glen Canyon Dam during water years 2006 through 2010.

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

Poch, L. A.; Veselka, T. D.; Palmer, C. S.

2011-08-22

Because of concerns about the impact that Glen Canyon Dam (GCD) operations were having on downstream ecosystems and endangered species, the Bureau of Reclamation (Reclamation) conducted an Environmental Impact Statement (EIS) on dam operations (DOE 1996). New operating rules and management goals for GCD that had been specified in the Record of Decision (ROD) (Reclamation 1996) were adopted in February 1997. In addition to issuing new operating criteria, the ROD mandated experimental releases for the purpose of conducting scientific studies. A report released in January 2011 examined the financial implications of the experimental flows that were conducted at the GCDmore » from 1997 to 2005. This report continues the analysis and examines the financial implications of the experimental flows conducted at the GCD from 2006 to 2010. An experimental release may have either a positive or negative impact on the financial value of energy production. This study estimates the financial costs of experimental releases, identifies the main factors that contribute to these costs, and compares the interdependencies among these factors. An integrated set of tools was used to compute the financial impacts of the experimental releases by simulating the operation of the GCD under two scenarios, namely, (1) a baseline scenario that assumes both that operations comply with the ROD operating criteria and the experimental releases that actually took place during the study period, and (2) a 'without experiments' scenario that is identical to the baseline scenario of operations that comply with the GCD ROD, except it assumes that experimental releases did not occur. The Generation and Transmission Maximization (GTMax) model was the main simulation tool used to dispatch GCD and other hydropower plants that comprise the Salt Lake City Area Integrated Projects (SLCA/IP). Extensive data sets and historical information on SLCA/IP powerplant characteristics, hydrologic conditions, and Western

4. DARK CANYON SIPHON VIEW ACROSS DARK CANYON AT ...

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

4. DARK CANYON SIPHON - VIEW ACROSS DARK CANYON AT LOCATION OF SIPHON. VIEW TO NORTHWEST - Carlsbad Irrigation District, Dark Canyon Siphon, On Main Canal, 1 mile South of Carlsbad, Carlsbad, Eddy County, NM

Rapid water quality change in the Elwha River estuary complex during dam removal

USGS Publications Warehouse

Foley, Melissa M.; Duda, Jeffrey J.; Beirne, Matthew M.; Paradis, Rebecca; Ritchie, Andrew; Warrick, Jonathan A.

2015-01-01

Dam removal in the United States is increasing as a result of structural concerns, sedimentation of reservoirs, and declining riverine ecosystem conditions. The removal of the 32 m Elwha and 64 m Glines Canyon dams from the Elwha River in Washington, U.S.A., was the largest dam removal project in North American history. During the 3 yr of dam removal—from September 2011 to August 2014—more than ten million cubic meters of sediment was eroded from the former reservoirs, transported downstream, and deposited throughout the lower river, river delta, and nearshore waters of the Strait of Juan de Fuca. Water quality data collected in the estuary complex at the mouth of the Elwha River document how conditions in the estuary changed as a result of sediment deposition over the 3 yr the dams were removed. Rapid and large-scale changes in estuary conditions—including salinity, depth, and turbidity—occurred 1 yr into the dam removal process. Tidal propagation into the estuary ceased following a large sediment deposition event that began in October 2013, resulting in decreased salinity, and increased depth and turbidity in the estuary complex. These changes have persisted in the system through dam removal, significantly altering the structure and functioning of the Elwha River estuary ecosystem.

Financial analysis of experimental releases conducted at Glen Canyon Dam during water year 2011

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

Poch, L. A.; Veselka, T. D.; Palmer, C. S.

2012-07-16

This report examines the financial implications of experimental flows conducted at the Glen Canyon Dam (GCD) in water year 2011. It is the third report in a series examining financial implications of experimental flows conducted since the Record of Decision (ROD) was adopted in February 1997 (Reclamation 1996). A report released in January 2011 examined water years 1997 to 2005 (Veselka et al. 2011), and a report released in August 2011 examined water years 2006 to 2010 (Poch et al. 2011). An experimental release may have either a positive or negative impact on the financial value of energy production. Thismore » study estimates the financial costs of experimental releases, identifies the main factors that contribute to these costs, and compares the interdependencies among these factors. An integrated set of tools was used to compute the financial impacts of the experimental releases by simulating the operation of the GCD under two scenarios, namely, (1) a baseline scenario that assumes both that operations comply with the ROD operating criteria and the experimental releases that actually took place during the study period, and (2) a 'without experiments' scenario that is identical to the baseline scenario of operations that comply with the GCD ROD, except it assumes that experimental releases did not occur. The Generation and Transmission Maximization (GTMax) model was the main simulation tool used to dispatch GCD and other hydropower plants that comprise the Salt Lake City Area Integrated Projects (SLCA/IP). Extensive data sets and historical information on SLCA/IP powerplant characteristics, hydrologic conditions, and Western Area Power Administration's (Western's) power purchase prices were used for the simulation. In addition to estimating the financial impact of experimental releases, the GTMax model was also used to gain insights into the interplay among ROD operating criteria, exceptions that were made to criteria to accommodate the experimental releases

Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River

USGS Publications Warehouse

Gartner, J.W.; Ganju, N.K.

2007-01-01

Discharge measurements were made by acoustic Doppler current profiler at two locations on the Colorado River during the 2004 controlled flood from Glen Canyon Dam, Arizona. Measurement hardware and software have constantly improved from the 1980s such that discharge measurements by acoustic profiling instruments are now routinely made over a wide range of hydrologic conditions. However, measurements made with instruments deployed from moving boats require reliable boat velocity data for accurate measurements of discharge. This is normally accomplished by using special acoustic bottom track pings that sense instrument motion over bottom. While this method is suitable for most conditions, high current flows that produce downstream bed sediment movement create a condition known as moving bed that will bias velocities and discharge to lower than actual values. When this situation exists, one solution is to determine boat velocity with satellite positioning information. Another solution is to use a lower frequency instrument. Discharge measurements made during the 2004 Glen Canyon controlled flood were subject to moving-bed conditions and frequent loss of bottom track. Due to site conditions and equipment availability, the measurements were conducted without benefit of external positioning information or lower frequency instruments. This paper documents and evaluates several techniques used to correct the resulting underestimated discharge measurements. One technique produces discharge values in good agreement with estimates from numerical model and measured hydrographs during the flood. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

Mineral resources of the Desolation Canyon, Turtle Canyon, and Floy Canyon Wilderness Study Areas, Carbon Emery, and Grand counties, Utah

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

Cashion, W.B.; Kilburn, J.E.; Barton, H.N.

1990-09-01

This paper reports on the Desolation Canyon, Turtle Canyon, and Floy Canyon Wilderness Study Areas which include 242,000 acres, 33,690 acres, and 23,140 acres. Coal deposits underlie all three study areas. Coal zones in the Blackhawk and Nelsen formations have identified bituminous coal resources of 22 million short tons in the Desolation Canyon Study Area, 6.3 million short tons in the Turtle Canyon Study Area, and 45 million short tons in the Floy Canyon Study Area. In-place inferred oil shale resources are estimated to contain 60 million barrels in the northern part of the Desolation Canyon area. Minor occurrences ofmore » uranium have been found in the southeastern part of the Desolation Canyon area and in the western part of the Floy Canyon area. Mineral resource potential for the study areas is estimated to be for coal, high for all areas, for oil and gas, high for the northern tract of the Desolation Canyon area and moderate for all other tracts, for bituminous sandstone, high for the northern part of the Desolation Canyon area, and low for all other tracts, for oil shale, low in all areas, for uranium, moderate for the Floy Canyon area and the southeastern part of the Desolation Canyon area and low for the remainder of the areas, for metals other than uranium, bentonite, zeolites, and geothermal energy, low in all areas, and for coal-bed methane unknown in all three areas.« less

The Irrigation Effect: How River Regulation Can Promote Some Riparian Vegetation.

PubMed

Gill, Karen M; Goater, Lori A; Braatne, Jeffrey H; Rood, Stewart B

2018-04-01

River regulation impacts riparian ecosystems by altering the hydrogeomorphic conditions that support streamside vegetation. Obligate riparian plants are often negatively impacted since they are ecological specialists with particular instream flow requirements. Conversely, facultative riparian plants are generalists and may be less vulnerable to river regulation, and could benefit from augmented flows that reduce drought stress during hot and dry periods. To consider this 'irrigation effect' we studied the facultative shrub, netleaf hackberry (Celtis reticulata), the predominant riparian plant along the Hells Canyon corridor of the Snake River, Idaho, USA, where dams produce hydropeaking, diurnal flow variation. Inventories of 235 cross-sectional transects revealed that hackberry was uncommon upstream from the reservoirs, sparse along the reservoir with seasonal draw-down and common along two reservoirs with stabilized water levels. Along the Snake River downstream, hackberry occurred in fairly continuous, dense bands along the high water line. In contrast, hackberry was sparsely scattered along the free-flowing Salmon River, where sandbar willow (Salix exigua), an obligate riparian shrub, was abundant. Below the confluence of the Snake and Salmon rivers, the abundance and distribution of hackberry were intermediate between the two upstream reaches. Thus, river regulation apparently benefited hackberry along the Snake River through Hells Canyon, probably due to diurnal pulsing that wets the riparian margin. We predict similar benefits for some other facultative riparian plants along other regulated rivers with hydropeaking during warm and dry intervals. To analyze the ecological impacts of hydropeaking we recommend assessing daily maxima, as well as daily mean river flows.

The Irrigation Effect: How River Regulation Can Promote Some Riparian Vegetation

NASA Astrophysics Data System (ADS)

Gill, Karen M.; Goater, Lori A.; Braatne, Jeffrey H.; Rood, Stewart B.

2018-04-01

River regulation impacts riparian ecosystems by altering the hydrogeomorphic conditions that support streamside vegetation. Obligate riparian plants are often negatively impacted since they are ecological specialists with particular instream flow requirements. Conversely, facultative riparian plants are generalists and may be less vulnerable to river regulation, and could benefit from augmented flows that reduce drought stress during hot and dry periods. To consider this `irrigation effect' we studied the facultative shrub, netleaf hackberry ( Celtis reticulata), the predominant riparian plant along the Hells Canyon corridor of the Snake River, Idaho, USA, where dams produce hydropeaking, diurnal flow variation. Inventories of 235 cross-sectional transects revealed that hackberry was uncommon upstream from the reservoirs, sparse along the reservoir with seasonal draw-down and common along two reservoirs with stabilized water levels. Along the Snake River downstream, hackberry occurred in fairly continuous, dense bands along the high water line. In contrast, hackberry was sparsely scattered along the free-flowing Salmon River, where sandbar willow ( Salix exigua), an obligate riparian shrub, was abundant. Below the confluence of the Snake and Salmon rivers, the abundance and distribution of hackberry were intermediate between the two upstream reaches. Thus, river regulation apparently benefited hackberry along the Snake River through Hells Canyon, probably due to diurnal pulsing that wets the riparian margin. We predict similar benefits for some other facultative riparian plants along other regulated rivers with hydropeaking during warm and dry intervals. To analyze the ecological impacts of hydropeaking we recommend assessing daily maxima, as well as daily mean river flows.

Recent Innovations in Monitoring Suspended-Sediment Mass Balance of the Colorado River Ecosystem Below Glen Canyon Dam: A laser-Based Approach

NASA Astrophysics Data System (ADS)

Melis, T. S.; Topping, D. J.; Rubin, D. M.; Agrawal, Y. C.

2002-12-01

Intensive monitoring of suspended-sediment in the Colorado River ecosystem below Glen Canyon Dam is a priority for environmental management. Historically, the program has been logistically complicated, costly and limited in spatial and temporal resolution. These elements have contributed to relatively large uncertainties in mass-balance estimates of sediment export. To improve mass-balance estimates, the Grand Canyon Monitoring and Research Center is field testing new and existing technologies to develop a continuous suspended-sediment transport protocol. A recent innovation includes use of optical forward-scattering instruments, LISST, in combination with programmable pumping samplers. The LISST-100 (Laser In-Situ Scattering and Transmissometry) is both a particle-size analyzer (size range 2.5 to 500 microns) and a transmissometer capable of measuring variable concentrations, depending on particle size. A second innovation, the LISST-25X, is a recently developed variation of the instrumentation that allows sand to be measured separately from finer particles. This is achieved by use of shaped focal plane detectors that compute 2 distinct weighted sums of angular scattering by suspended particles. The LISST-25X currently collects volume-concentration and grain size (Sauter-mean-diameter) data for suspended particles at four sites below the dam. Unit values are derived by averaging 1000 individual measurements every 15-minutes (sampling about 1.1 liters of water per hour). The volume-to-mass conversion is made once average particle density has been gravimetrically determined through conventional methods. During high-concentration conditions, laser-transmission values (T) can fall outside of the user-defined minimal threshold (20

A Vegetation Database for the Colorado River Ecosystem from Glen Canyon Dam to the Western Boundary of Grand Canyon National Park, Arizona

USGS Publications Warehouse

Ralston, Barbara E.; Davis, Philip A.; Weber, Robert M.; Rundall, Jill M.

2008-01-01

A vegetation database of the riparian vegetation located within the Colorado River ecosystem (CRE), a subsection of the Colorado River between Glen Canyon Dam and the western boundary of Grand Canyon National Park, was constructed using four-band image mosaics acquired in May 2002. A digital line scanner was flown over the Colorado River corridor in Arizona by ISTAR Americas, using a Leica ADS-40 digital camera to acquire a digital surface model and four-band image mosaics (blue, green, red, and near-infrared) for vegetation mapping. The primary objective of this mapping project was to develop a digital inventory map of vegetation to enable patch- and landscape-scale change detection, and to establish randomized sampling points for ground surveys of terrestrial fauna (principally, but not exclusively, birds). The vegetation base map was constructed through a combination of ground surveys to identify vegetation classes, image processing, and automated supervised classification procedures. Analysis of the imagery and subsequent supervised classification involved multiple steps to evaluate band quality, band ratios, and vegetation texture and density. Identification of vegetation classes involved collection of cover data throughout the river corridor and subsequent analysis using two-way indicator species analysis (TWINSPAN). Vegetation was classified into six vegetation classes, following the National Vegetation Classification Standard, based on cover dominance. This analysis indicated that total area covered by all vegetation within the CRE was 3,346 ha. Considering the six vegetation classes, the sparse shrub (SS) class accounted for the greatest amount of vegetation (627 ha) followed by Pluchea (PLSE) and Tamarix (TARA) at 494 and 366 ha, respectively. The wetland (WTLD) and Prosopis-Acacia (PRGL) classes both had similar areal cover values (227 and 213 ha, respectively). Baccharis-Salix (BAXX) was the least represented at 94 ha. Accuracy assessment of the

Environmental and human impact on the sedimentary dynamic in the Rhone Delta subaquatic canyons (France-Switzerland)

NASA Astrophysics Data System (ADS)

Arantegui, A.; Corella, J. P.; Loizeau, J. L.; Anselmetti, F. S.; Girardclos, S.

2012-04-01

Deltas are very sensitive environments and highly vulnerable to variations in water discharge and the amount of suspended sediment load provided by the delta-forming currents. Human activities in the watershed, such as building of dams and irrigation ditches, or river bed deviations, may affect the discharge regime and sediment input, thus affecting delta growth. Underwater currents create deeply incised canyons cutting into the delta lobes. Understanding the sedimentary processes in these subaquatic canyons is crucial to reconstruct the fluvial evolution and human impact on deltaic environments and to carry out a geological risk assessment related to mass movements, which may affect underwater structures and civil infractructure. Recently acquired high-resolution multibeam bathymetry on the Rhone Delta in Lake Geneva (Sastre et al. 2010) revealed the complexity of the underwater morphology formed by active and inactive canyons first described by Forel (1892). In order to unravel the sedimentary processes and sedimentary evolution in these canyons, 27 sediment cores were retrieved in the distal part of each canyon and in the canyon floor/levee complex of the active canyon. Geophysical, sedimentological, geochemical and radiometric dating techniques were applied to analyse these cores. Preliminary data show that only the canyon originating at the current river mouth is active nowadays, while the others remain inactive since engineering works in the watershed occurred, confirming Sastre et al. (2010). However, alternating hemipelagic and turbiditic deposits on the easternmost canyons, evidence underflow processes during the last decades as well. Two canyons, which are located close to the Rhone river mouth, correspond to particularly interesting deeply incised crevasse channels formed when the underwater current broke through the outer bend of a meander in the proximal northern levee. In these canyons, turbidites occur in the sediment record indicating ongoing

Geologic framework of thermal springs, Black Canyon, Nevada and Arizona

USGS Publications Warehouse

Beard, L. Sue; Anderson, Zachary W.; Felger, Tracey J.; Seixas, Gustav B.

2014-01-01

Thermal springs in Black Canyon of the Colorado River, downstream of Hoover Dam, are important recreational, ecological, and scenic features of the Lake Mead National Recreation Area. This report presents the results from a U.S. Geological Survey study of the geologic framework of the springs. The study was conducted in cooperation with the National Park Service and funded by both the National Park Service and National Cooperative Geologic Mapping Program of the U.S. Geological Survey. The report has two parts: A, a 1:48,000-scale geologic map created from existing geologic maps and augmented by new geologic mapping and geochronology; and B, an interpretive report that presents results based on a collection of fault kinematic data near springs within Black Canyon and construction of 1:100,000-scale geologic cross sections that extend across the western Lake Mead region. Exposures in Black Canyon are mostly of Miocene volcanic rocks, underlain by crystalline basement composed of Miocene plutonic rocks or Proterozoic metamorphic rocks. The rocks are variably tilted and highly faulted. Faults strike northwest to northeast and include normal and strike-slip faults. Spring discharge occurs along faults intruded by dacite dikes and plugs; weeping walls and seeps extend away from the faults in highly fractured rock or relatively porous volcanic breccias, or both. Results of kinematic analysis of fault data collected along tributaries to the Colorado River indicate two episodes of deformation, consistent with earlier studies. The earlier episode formed during east-northeast-directed extension, and the later during east-southeast-directed extension. At the northern end of the study area, pre-existing fault blocks that formed during the first episode were rotated counterclockwise along the left-lateral Lake Mead Fault System. The resulting fault pattern forms a complex arrangement that provides both barriers and pathways for groundwater movement within and around Black

Hydro-geomorphology of the middle Elwha River, Washington, following dam removal

NASA Astrophysics Data System (ADS)

Morgan, J. A.; Nelson, P. A.; Brogan, D. J.

2017-12-01

Dam removal is an increasingly common river restoration practice, which can produce dramatic increases in sediment supply to downstream reaches. There remains, however, considerable uncertainty in how mesoscale morphological units (e.g., riffles and pools) respond to the flow and sediment supply changes associated with dam removal. The recent removal of Glines Canyon Dam on the Elwha River in Washington State provides a natural setting to explore how increased sediment supply due to dam removal may affect downstream reaches. Here, we present observations and surveys documenting how a 1 km reach, located approximately 5 km downstream of the former dam site, has evolved following dam removal. Annual topographic/bathymetric surveys were conducted in 2014-2016 using RTK-GNSS methods, and these surveys were coupled with airborne lidar to create continuous surface maps of the valley bottom. Differencing the elevation models reveals channel widening and migration due to lateral bank retreat and bar aggradation. Analysis of aerial imagery dating back to 1939 suggests that rates of both widening and meander migration have increased following dam removal. We also used results from depth-averaged hydrodynamic modeling with a fuzzy c-means clustering approach to delineate riffle and pool units; this analysis suggests that both riffles and pools stayed relatively consistent from 2014-2015, while both areas decreased from 2015 to 2016. Without any considerable changes to the hydrologic regime these higher rates of change are implied to be the result of the increased sediment supply. Our results, which indicate an increased dynamism due directly to the amplified sediment supply, have the potential to further inform river managers and restoration specialists who oversee projects related to changing sediment regimes.

Imported fire ants: the ants from hell!

PubMed

Freeman, T M

1994-01-01

Imported fire ants may certainly be considered the ANTS FROM HELL! This review focuses on both the interesting entomology of fire ants and the important medical characteristics of fire ant stings. They sting and they kill; they destroy; they mate in mid-air; and we may not be able to stop them. However, although they inject extremely potent venom, individuals can prevent secondary infections by leaving the so-called pustules alone and not opening them. Individuals who suffer systemic reactions may receive adequate treatment with the whole body extract immunotherapy.

Automated remote cameras for monitoring alluvial sandbars on the Colorado River in Grand Canyon, Arizona

USGS Publications Warehouse

Grams, Paul E.; Tusso, Robert B.; Buscombe, Daniel

2018-02-27

Automated camera systems deployed at 43 remote locations along the Colorado River corridor in Grand Canyon National Park, Arizona, are used to document sandbar erosion and deposition that are associated with the operations of Glen Canyon Dam. The camera systems, which can operate independently for a year or more, consist of a digital camera triggered by a separate data controller, both of which are powered by an external battery and solar panel. Analysis of images for categorical changes in sandbar size show deposition at 50 percent or more of monitoring sites during controlled flood releases done in 2012, 2013, 2014, and 2016. The images also depict erosion of sandbars and show that erosion rates were highest in the first 3 months following each controlled flood. Erosion rates were highest in 2015, the year of highest annual dam release volume. Comparison of the categorical estimates of sandbar change agree with sandbar change (erosion or deposition) measured by topographic surveys in 76 percent of cases evaluated. A semiautomated method for quantifying changes in sandbar area from the remote-camera images by rectifying the oblique images and segmenting the sandbar from the rest of the image is presented. Calculation of sandbar area by this method agrees with sandbar area determined by topographic survey within approximately 8 percent and allows quantification of sandbar area monthly (or more frequently).

Coastal and lower Elwha River, Washington, prior to dam removal--history, status, and defining characteristics: Chapter 1 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

USGS Publications Warehouse

Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

Characterizing the physical and biological characteristics of the lower Elwha River, its estuary, and adjacent nearshore habitats prior to dam removal is essential to monitor changes to these areas during and following the historic dam-removal project set to begin in September 2011. Based on the size of the two hydroelectric projects and the amount of sediment that will be released, the Elwha River in Washington State will be home to the largest river restoration through dam removal attempted in the United States. Built in 1912 and 1927, respectively, the Elwha and Glines Canyon Dams have altered key physical and biological characteristics of the Elwha River. Once abundant salmon populations, consisting of all five species of Pacific salmon, are restricted to the lower 7.8 river kilometers downstream of Elwha Dam and are currently in low numbers. Dam removal will reopen access to more than 140 km of mainstem, flood plain, and tributary habitat, most of which is protected within Olympic National Park. The high capture rate of river-borne sediments by the two reservoirs has changed the geomorphology of the riverbed downstream of the dams. Mobilization and downstream transport of these accumulated reservoir sediments during and following dam removal will significantly change downstream river reaches, the estuary complex, and the nearshore environment. To introduce the more detailed studies that follow in this report, we summarize many of the key aspects of the Elwha River ecosystem including a regional and historical context for this unprecedented project.

Stage-Discharge Relations for the Colorado River in Glen, Marble, and Grand Canyons, Arizona, 1990-2005

USGS Publications Warehouse

Hazel, Joseph E.; Kaplinski, Matt; Parnell, Rod; Kohl, Keith; Topping, David J.

2007-01-01

This report presents stage-discharge relations for 47 discrete locations along the Colorado River, downstream from Glen Canyon Dam. Predicting the river stage that results from changes in flow regime is important for many studies investigating the effects of dam operations on resources in and along the Colorado River. The empirically based stage-discharge relations were developed from water-surface elevation data surveyed at known discharges at all 47 locations. The rating curves accurately predict stage at each location for discharges between 141 cubic meters per second and 1,274 cubic meters per second. The coefficient of determination (R2) of the fit to the data ranged from 0.993 to 1.00. Given the various contributing errors to the method, a conservative error estimate of ?0.05 m was assigned to the rating curves.

Origin of Florida Canyon and the role of spring sapping on the formation of submarine box canyons

USGS Publications Warehouse

Paull, Charles K.; Spiess, Fred N.; Curray, Joseph R.; Twichell, David C.

1990-01-01

Florida Canyon, one of a series of major submarine canyons on the southwestern edge of the Florida Platform, was surveyed using GLORIA, SeaBeam, and Deep-Tow technologies, and it was directly observed during three DSRV Alvin dives. Florida Canyon exhibits two distinct morphologies: a broad V-shaped upper canyon and a deeply entrenched, flat-floored, U-shaped lower canyon. The flat- floored lower canyon extends 20 km into the Florida Platform from the abyssal Gulf. The lower canyon ends abruptly at an ∼3 km in diameter semicircular headwall that rises 750 m with a >60° slope angle to the foot of the upper canyon. The sides of the lower canyon are less steep than its headwall and are characterized by straight faces that occur along preferred orientations and indicate a strong joint control. The upper canyon is characterized by a gently sloping, straight V-shaped central valley cut into a broad terrace. The flat floor of the upper canyon continues as terraces along the upper walls of the lower canyon. On the flanks of the upper canyon, there are five >50-m-deep, >0.5-km-wide, closed sink-hole-like depressions which indicate subsurface dissolution within the platform. The origin of the lower canyon is difficult to explain with traditional models of submarine canyon formation by external physical processes. The movement of ground water, probably with high salinities and reduced compounds along regional joints, may have focused the corrosive force of submarine spring sapping at the head of the lower canyon to produce the canyon's present shape.

Regulation leads to increases in riparian vegetation, but not direct allochthonous inputs, along the Colorado River in Grand Canyon, Arizona

USGS Publications Warehouse

Kennedy, T.A.; Ralston, B.E.

2012-01-01

Dams and associated river regulation have led to the expansion of riparian vegetation, especially nonnative species, along downstream ecosystems. Nonnative saltcedar is one of the dominant riparian plants along virtually every major river system in the arid western United States, but allochthonous inputs have never been quantified along a segment of a large river that is dominated by saltcedar. We developed a novel method for estimating direct allochthonous inputs along the 387km-long reach of the Colorado River downstream of Glen Canyon Dam that utilized a GIS vegetation map developed from aerial photographs, empirical and literature-derived litter production data for the dominant vegetation types, and virtual shorelines of annual peak discharge (566m 3s -1 stage elevation). Using this method, we estimate that direct allochthonous inputs from riparian vegetation for the entire reach studied total 186metric tonsyear -1, which represents mean inputs of 470gAFDMm -1year -1 of shoreline or 5.17gAFDMm -2year -1 of river surface. These values are comparable to allochthonous inputs for other large rivers and systems that also have sparse riparian vegetation. Nonnative saltcedar represents a significant component of annual allochthonous inputs (36% of total direct inputs) in the Colorado River. We also estimated direct allochthonous inputs for 46.8km of the Colorado River prior to closure of Glen Canyon Dam using a vegetation map that was developed from historical photographs. Regulation has led to significant increases in riparian vegetation (270-319% increase in cover, depending on stage elevation), but annual allochthonous inputs appear unaffected by regulation because of the lower flood peaks on the post-dam river. Published in 2010 by John Wiley & Sons, Ltd.

Effects of Climatic Variability and Change on Upland Vegetation in the Blue Mountains [Chapter 6].

Treesearch

Becky K. Kerns; David C. Powell; Sabine Mellmann-Brown; Gunnar Carnwath; John Kim

2017-01-01

The Blue Mountains ecoregion (BME) extends from the Ochoco Mountains in central Oregon to Hells Canyon of the Snake River in extreme northeastern Oregon and adjacent Idaho, and then north to the deeply carved canyons and basalt rimrock of southeastern Washington (see fig. 1.1 in chapter 1). The BME consists of a series of mountain ranges occurring in a southwest to...

Hydrogeology and sources of water to select springs in Black Canyon, south of Hoover Dam, Lake Mead National Recreation Area, Nevada and Arizona

USGS Publications Warehouse

Moran, Michael J.; Wilson, Jon W.; Beard, L. Sue

2015-11-03

Several major faults, including the Salt Cedar Fault and the Palm Tree Fault, play an important role in the movement of groundwater. Groundwater may move along these faults and discharge where faults intersect volcanic breccias or fractured rock. Vertical movement of groundwater along faults is suggested as a mechanism for the introduction of heat energy present in groundwater from many of the springs. Groundwater altitudes in the study area indicate a potential for flow from Eldorado Valley to Black Canyon although current interpretations of the geology of this area do not favor such flow. If groundwater from Eldorado Valley discharges at springs in Black Canyon then the development of groundwater resources in Eldorado Valley could result in a decrease in discharge from the springs. Geology and structure indicate that it is not likely that groundwater can move between Detrital Valley and Black Canyon. Thus, the development of groundwater resources in Detrital Valley may not result in a decrease in discharge from springs in Black Canyon.

The Individual and Additive Effects of Vegetation Encroachment and Hydrologic Alteration on Sediment Connectivity in Grand Canyon

NASA Astrophysics Data System (ADS)

Kasprak, A.; Buscombe, D.; Caster, J.; Grams, P. E.; Sankey, J. B.

2016-12-01

Sediment connectivity is a vital component of the eco-geomorphic function of river systems, and the pathways of sediment transfer in river valleys often shift in response to channel disturbance and development. Along the Colorado River downstream of Glen Canyon Dam (completed in 1963), flow alteration for hydropower generation has increased baseflows while reducing the magnitude of regularly-occurring floods, and vegetation has subsequently colonized many channel-margin surfaces. In this dryland, canyon-bound river system, aeolian transport has historically been a vital component of sediment connectivity, yet the relative roles of altered hydrology and vegetation on the extent of sand available for windblown transport are unknown. Here we use a fusion of high-resolution spatial datasets including channel bathymetry and bed classification derived from single- and multibeam echosounding and total station surveys, exposed sand mapping and vegetation classification from multispectral imagery, in concert with a 94 year discharge record and one-dimensional hydraulic modeling to quantify changes in sand availability along a 48 km reach of the Colorado River. We find that hydrologic alteration alone has reduced areal sand availability by approximately 15% when comparing the pre- and post-dam flow records, while vegetation encroachment has had an even greater effect. More than half of the total sand area in the study reach is located at low flow stages below 226 m3/s, meaning that small reductions in baseflow discharge have the potential to expose large quantities of sand, and we subsequently explore the relative effect of alternative flow regimes on sand exposure during the postdam period. The ability to quantify and explore the efficacy of river management strategies on large-scale sediment connectivity has the potential to inform eco-geomorphic management of the Colorado River in Grand Canyon and other regulated rivers worldwide.

Elwha River dam removal: A major opportunity for salmon and steelhead recolonization

USGS Publications Warehouse

Pess, George R.; Brenkman, Samuel J.; Winans, Gary A.; McHenry, Michael L.; Duda, Jeffrey J.; Beechie, Timothy J.

2010-01-01

In this in-depth paper, authors George R. Pess, Gary A. Winans and Timothy J. Beechie of the NOAA Fisheries, Northwest Fisheries Science Center in Seattle, Samuel J. Brenkman of the National Park Service, Olympic National Park, Michael L. McHenry of the Lower Elwha Klallam Tribe and Jeffrey J. Duda of the U.S. Geological Survey, Western Fisheries Research Center in Seattle, provide an historical overview of the Elwha River system, and its native anadromous fish runs and the prospect of their recolonization after the Elwha and Glines Canyon dams are removed.

Escape from Management Hell: 12 Tales of Horror, Humor, and Heroism.

ERIC Educational Resources Information Center

Gilbreath, Robert D.

This book offers a set of stories in which corporate executives demonstrate the folly and futility of their own business practices. In the stories, 12 executives are trying to escape from a hell of their own making. The tales provide insights into the management woes with which people at all levels deal on a daily basis. Topics include: the…

Seasonal and spatial patterns of growth of rainbow trout in the Colorado River in Grand Canyon, AZ

USGS Publications Warehouse

Yard, Micheal D.; Korman, Josh; Walters, Carl J.; Kennedy, T.A.

2016-01-01

Rainbow trout (Oncorhynchus mykiss) have been purposely introduced in many regulated rivers, with inadvertent consequences on native fishes. We describe how trout growth rates and condition could be influencing trout population dynamics in a 130 km section of the Colorado River below Glen Canyon Dam based on a large-scale mark–recapture program where ∼8000 rainbow trout were recaptured over a 3-year period (2012–2014). There were strong temporal and spatial variations in growth in both length and weight as predicted from von Bertalanffy and bioenergetic models, respectively. There was more evidence for seasonal variation in the growth coefficient and annual variation in the asymptotic length. Bioenergetic models showed more variability for growth in weight across seasons and years than across reaches. These patterns were consistent with strong seasonal variation in invertebrate drift and effects of turbidity on foraging efficiency. Highest growth rates and relative condition occurred in downstream reaches with lower trout densities. Results indicate that reduction in rainbow trout abundance in Glen Canyon will likely increase trout size in the tailwater fishery and may reduce downstream dispersal into Grand Canyon.

Preliminary geologic map of Black Canyon and surrounding region, Nevada and Arizona

USGS Publications Warehouse

Felger, Tracey J.; Beard, L. Sue; Anderson, Zachary W.; Fleck, Robert J.; Wooden, Joseph L.; Seixas, Gustav B.

2014-01-01

Thermal springs in Black Canyon of the Colorado River, downstream of Hoover Dam, are important recreational, ecological, and scenic features of the Lake Mead National Recreation Area. This report presents the results from a U.S. Geological Survey study of the geologic framework of the springs. The study was conducted in cooperation with the National Park Service and funded by both the National Park Service and National Cooperative Geologic Mapping Program of the U.S. Geological Survey. The report has two parts: A, a 1:48,000-scale geologic map created from existing geologic maps and augmented by new geologic mapping and geochronology; and B, an interpretive report that presents results based on a collection of fault kinematic data near springs within Black Canyon and construction of 1:100,000-scale geologic cross sections that extend across the western Lake Mead region. Exposures in Black Canyon are mostly of Miocene volcanic rocks, underlain by crystalline basement composed of Miocene plutonic rocks or Proterozoic metamorphic rocks. The rocks are variably tilted and highly faulted. Faults strike northwest to northeast and include normal and strike-slip faults. Spring discharge occurs along faults intruded by dacite dikes and plugs; weeping walls and seeps extend away from the faults in highly fractured rock or relatively porous volcanic breccias, or both. Results of kinematic analysis of fault data collected along tributaries to the Colorado River indicate two episodes of deformation, consistent with earlier studies. The earlier episode formed during east-northeast-directed extension, and the later during east-southeast-directed extension. At the northern end of the study area, pre-existing fault blocks that formed during the first episode were rotated counterclockwise along the left-lateral Lake Mead Fault System. The resulting fault pattern forms a complex arrangement that provides both barriers and pathways for groundwater movement within and around Black

Anticipated sediment delivery to the lower Elwha River during and following dam removal: Chapter 2 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

USGS Publications Warehouse

Czuba, Christiana R.; Randle, Timothy J.; Bountry, Jennifer A.; Magirl, Christopher S.; Czuba, Jonathan A.; Curran, Christopher A.; Konrad, Christopher P.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

During and after the planned incremental removal of two large, century-old concrete dams between 2011 and 2014, the sediment-transport regime in the lower Elwha River of western Washington will initially spike above background levels and then return to pre-dam conditions some years after complete dam removal. Measurements indicate the upper reaches of the steep-gradient Elwha River, draining the northeast section of the Olympic Mountains, carries between an estimated 120,000 and 290,000 cubic meters of sediment annually. This large load has deposited an estimated 19 million cubic meters of sediment within the two reservoirs formed by the Elwha and Glines Canyon Dams. It is anticipated that from 7 to 8 million cubic meters of this trapped sediment will mobilize and transport downstream during and after dam decommissioning, restoring the downstream sections of the sediment-starved river and nearshore marine environments. Downstream transport of sediment from the dam sites will have significant effects on channel morphology, water quality, and aquatic habitat during and after dam removal. Sediment concentrations are expected to be between 200 and 1,000 milligrams per liter during and just after dam removal and could rise to as much as 50,000 milligrams per liter during high flows. Downstream sedimentation in the river channel and flood plain will be potentially large, particularly in the lower Elwha River, an alluvial reach with a wide flood plain. Overall aggradation could be as much as one to several meters. Not all reservoir sediment, however, will be released to the river. Some material will remain on hill slopes and flood plains within the drained reservoirs in quantities that will depend on the hydrology, precipitation, and mechanics of the incising channel. Eventually, vegetation will stabilize this remaining reservoir sediment, and the overall sediment load in the restored river will return to pre-dam levels.

Coastal habitat and biological community response to dam removal on the Elwha River

USGS Publications Warehouse

Foley, Melissa M.; Warrick, Jonathan A.; Ritchie, Andrew C.; Stevens, Andrew; Shafroth, Patrick B.; Duda, Jeff; Beirne, Matthew M.; Paradis, Rebecca; Gelfenbaum, Guy R.; McCoy, Randall; Cubley, Erin S.

2017-01-01

Habitat diversity and heterogeneity play a fundamental role in structuring ecological communities. Dam emplacement and removal can fundamentally alter habitat characteristics, which in turn can affect associated biological communities. Beginning in the early 1900s, the Elwha and Glines Canyon dams in Washington, USA, withheld an estimated 30 million tonnes of sediment from river, coastal, and nearshore habitats. During the staged removal of these dams—the largest dam removal project in history—over 14 million tonnes of sediment were released from the former reservoirs. Our interdisciplinary study in coastal habitats—the first of its kind—shows how the physical changes to the river delta and estuary habitats during dam removal were linked to responses in biological communities. Sediment released during dam removal resulted in over a meter of sedimentation in the estuary and over 400 m of expansion of the river mouth delta landform. These changes increased the amount of supratidal and intertidal habitat, but also reduced the influx of seawater into the pre-removal estuary complex. The effects of these geomorphic and hydrologic changes cascaded to biological systems, reducing the abundance of macroinvertebrates and fish in the estuary and shifting community composition from brackish to freshwater-dominated species. Vegetation did not significantly change on the delta, but pioneer vegetation increased during dam removal, coinciding with the addition of newly available habitat. Understanding how coastal habitats respond to large-scale human stressors—and in some cases the removal of those stressors—is increasingly important as human uses and restoration activities increase in these habitats.

Geomorphic process fingerprints in submarine canyons

USGS Publications Warehouse

Brothers, Daniel S.; ten Brink, Uri S.; Andrews, Brian D.; Chaytor, Jason D.; Twichell, David C.

2013-01-01

Submarine canyons are common features of continental margins worldwide. They are conduits that funnel vast quantities of sediment from the continents to the deep sea. Though it is known that submarine canyons form primarily from erosion induced by submarine sediment flows, we currently lack quantitative, empirically based expressions that describe the morphology of submarine canyon networks. Multibeam bathymetry data along the entire passive US Atlantic margin (USAM) and along the active central California margin near Monterey Bay provide an opportunity to examine the fine-scale morphology of 171 slope-sourced canyons. Log–log regression analyses of canyon thalweg gradient (S) versus up-canyon catchment area (A) are used to examine linkages between morphological domains and the generation and evolution of submarine sediment flows. For example, canyon reaches of the upper continental slope are characterized by steep, linear and/or convex longitudinal profiles, whereas reaches farther down canyon have distinctly concave longitudinal profiles. The transition between these geomorphic domains is inferred to represent the downslope transformation of debris flows into erosive, canyon-flushing turbidity flows. Over geologic timescales this process appears to leave behind a predictable geomorphic fingerprint that is dependent on the catchment area of the canyon head. Catchment area, in turn, may be a proxy for the volume of sediment released during geomorphically significant failures along the upper continental slope. Focused studies of slope-sourced submarine canyons may provide new insights into the relationships between fine-scale canyon morphology and down-canyon changes in sediment flow dynamics.

Measurements of wind, aeolian sand transport, and precipitation in the Colorado River corridor, Grand Canyon, Arizona; January 2005 to January 2006

USGS Publications Warehouse

Draut, Amy E.; Rubin, David M.

2006-01-01

evaluate the potential for aeolian reworking of new fluvial sand deposits, and restoration of higher-elevation aeolian deposits, following the 60-hour controlled flood release from Glen Canyon Dam in November 2004. Substantial deposition of new sand occurred at all study sites during this high-flow experiment, but most of the new sediment was eroded by high flow fluctuations between January and March 2005. Comparison of aeolian sand transport in the spring windy seasons of the preand post-flood years indicates that, where some of the flood-deposited sand remained by spring, aeolian sand transport was significantly higher than during the pre-flood spring. Gully incision in an aeolian dune field was observed to be partially ameliorated by deposition of wind-blown sand derived from a nearby 2004 flood deposit. These results imply that sediment-rich controlled floods can renew sand deposition in aeolian dune fields above the flood-stage elevation. The potential for restoration of archaeological sites in aeolian deposits can be maximized by using dam operations that maximize the open sand area on fluvial sandbars during spring, when aeolian sediment transport is greatest.

Multiple constraints on the age of a Pleistocene lava dam across the Little Colorado River at Grand Falls, Arizona

USGS Publications Warehouse

Duffield, W.; Riggs, N.; Kaufman, D.; Champion, D.; Fenton, C.; Forman, S.; McIntosh, W.; Hereford, R.; Plescia, J.; Ort, M.

2006-01-01

The Grand Falls basalt lava flow in northern Arizona was emplaced in late Pleistocene time. It flowed 10 km from its vent area to the Little Colorado River, where it cascaded into and filled a 65-m-deep canyon to form the Grand Falls lava dam. Lava continued ???25 km downstream and ???1 km onto the far rim beyond where the canyon was filled. Subsequent fluvial sedimentation filled the reservoir behind the dam, and eventually the river established a channel along the margin of the lava flow to the site where water falls back into the pre-eruption canyon. The ca. 150 ka age of the Grand Falls flow provided by whole-rock K-Ar analysis in the 1970s is inconsistent with the preservation of centimeter-scale flow-top features on the surface of the flow and the near absence of physical and chemical weathering on the flow downstream of the falls. The buried Little Colorado River channel and the present-day channel are at nearly the same elevation, indicating that very little, if any, regional downcutting has occurred since emplacement of the flow. Newly applied dating techniques better define the age of the lava dam. Infrared-stimulated luminescence dating of silty mudstone baked by the lava yielded an age of 19.6 ?? 1.2 ka. Samples from three noneroded or slightly eroded outcrops at the top of the lava flow yielded 3He cosmogenic ages of 16 ?? 1 ka, 17 ?? 1 ka, and 20 ?? 1 ka. A mean age of 8 ?? 19 ka was obtained from averaging four samples using the 40Ar/39Ar step-heating method. Finally, paleomagnetic directions in lava samples from two sites at Grand Falls and one at the vent area are nearly identical and match the curve of magnetic secular variation at ca. 15 ka, 19 ka, 23 ka, and 28 ka. We conclude that the Grand Falls flow was emplaced at ca. 20 ka. ?? 2006 Geological Society of America.

Financial Analysis of Experimental Releases Conducted at Glen Canyon Dam during Water Year 2015

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

Graziano, D. J.; Poch, L. A.; Veselka, T. D.

This report examines the financial implications of experimental flows conducted at the Glen Canyon Dam (GCD) in water year (WY) 2015. It is the seventh report in a series examining the financial implications of experimental flows conducted since the Record of Decision (ROD) was adopted in February 1997 (Reclamation 1996). A report released in January 2011 examined WYs 1997 to 2005 (Veselka et al. 2011); a report released in August 2011 examined WYs 2006 to 2010 (Poch et al. 2011); a report released June 2012 examined WY 2011 (Poch et al. 2012); a report released April 2013 examined WY 2012more » (Poch et al. 2013); a report released June 2014 examined WY 2013 (Graziano et al. 2014); and a report released September 2015 examined WY 2014 (Graziano et al. 2015). An experimental release may have either a positive or negative impact on the financial value of energy production. Only one experimental release was conducted at GCD in WY 2015; specifically, a high flow experimental (HFE) release conducted in November 2014. For this experimental release, financial costs of approximately $2.1 million were incurred because the HFE required sustained water releases that exceeded the powerplant’s maximum flow rate. In addition, during the month of the experiment, operators were not allowed to shape GCD power production to either follow firm power customer loads or to respond to market prices. This study identifies the main factors that contribute to HFE costs and examines the interdependencies among these factors. It applies an integrated set of tools to estimate financial impacts by simulating the GCD operations under two scenarios: (1) a baseline scenario that mimics both HFE operations during the experiment and during the rest of the year when it complies with the 1996 ROD operating criteria, and (2) a “without experiments” scenario that is identical to the baseline except it assumes that the HFE did not occur. The Generation and Transmission Maximization (GTMax) model

Basal Resources in Backwaters of the Colorado River Below Glen Canyon Dam-Effects of Discharge Regimes and Comparison with Mainstem Depositional Environments

USGS Publications Warehouse

Behn, Katherine E.; Kennedy, Theodore A.; Hall, Robert O.

2010-01-01

Eight species of fish were native to the Colorado River before the closure of Glen Canyon Dam, but only four of these native species are currently present. A variety of factors are responsible for the loss of native fish species and the limited distribution and abundance of those that remain. These factors include cold and constant water temperatures, predation and competition with nonnative fish species, and food limitation. Backwaters are areas of stagnant flow in a return-current channel and are thought to be critical rearing habitat for juvenile native fish. Backwaters can be warmer than the main channel and may support higher rates of food production. Glen Canyon Dam is a peaking hydropower facility and, as a result, has subdaily variation in discharge because of changes in demand for power. Stable daily discharges may improve the quality of nearshore rearing habitats such as backwaters by increasing warming, stabilizing the substrate, and increasing food production. To evaluate whether backwaters have greater available food resources than main-channel habitats, and how resource availability in backwaters is affected by stable flow regimes, we quantified water-column and benthic food resources in backwaters seasonally for 1 year using both standing (organic matter concentration/density; chlorophyll a concentration/density; zooplankton concentration; benthic invertebrate density and biomass) and process measurements (chamber estimates of ecosystem metabolism). We compared backwater resource measurements with comparable data from main-channel habitats, and compared backwater data collected during stable discharge with data collected when there was subdaily variation in discharge. Rates of primary production in backwaters (mean gross primary production of 1.7 g O2/m2/d) and the main channel (mean gross primary production of 2.0 g O2/m2/d) were similar. Benthic organic matter standing stock (presented as ash-free dry mass-AFDM) was seven times higher in backwaters

Acquisition, calibration, and performance of airborne high-resolution ADS40 SH52 sensor data for monitoring the Colorado River below Glen Canyon Dam

NASA Astrophysics Data System (ADS)

Davis, P. A.; Cagney, L. E.; Kohl, K. A.; Gushue, T. M.; Fritzinger, C.; Bennett, G. E.; Hamill, J. F.; Melis, T. S.

2010-12-01

Periodically, the Grand Canyon Monitoring and Research Center of the U.S. Geological Survey collects and interprets high-resolution (20-cm), airborne multispectral imagery and digital surface models (DSMs) to monitor the effects of Glen Canyon Dam operations on natural and cultural resources of the Colorado River in Grand Canyon. We previously employed the first generation of the ADS40 in 2000 and the Zeiss-Imaging Digital Mapping Camera (DMC) in 2005. Data from both sensors displayed band-image misregistration owing to multiple sensor optics and image smearing along abrupt scarps due to errors in image rectification software, both of which increased post-processing time, cost, and errors from image classification. Also, the near-infrared gain on the early, 8-bit ADS40 was not properly set and its signal was saturated for the more chlorophyll-rich vegetation, which limited our vegetation mapping. Both sensors had stereo panchromatic capability for generating a DSM. The ADS40 performed to specifications; the DMC failed. In 2009, we employed the new ADS40 SH52 to acquire 11-bit multispectral data with a single lens (20-cm positional accuracy), as well as stereo panchromatic data that provided a 1-m cell DSM (40-cm root-mean-square vertical error at one sigma). Analyses of the multispectral data showed near-perfect registration of its four band images at our 20-cm resolution, a linear response to ground reflectance, and a large dynamic range and good sensitivity (except for the blue band). Data were acquired over a 10-day period for the 450-km-long river corridor in which acquisition time and atmospheric conditions varied considerably during inclement weather. We received 266 orthorectified flightlines for the corridor, choosing to calibrate and mosaic the data ourselves to ensure a flawless mosaic with consistent, realistic spectral information. A linear least-squares cross-calibration of overlapping flightlines for the corridor showed that the dominate factors in

History of Snake River Canyon Indicated by Revised Stratigraphy of Snake River Group Near Hagerman and King Hill, Idaho: With a Section on Paleomagnetism

USGS Publications Warehouse

Malde, Harold E.; Cox, Allan

1971-01-01

. From that place the former Snake River canyon, also now concealed by lava, continued west to Bancroft Springs and thence along a route close to the present canyon to King Hill. To become entrenched in a canyon 500 feet deep, the Snake River downstream from Hagerman became progressively more incised while its upstream route was pushed south in several earlier canyons by intermittent lava flows. Distinctive gravel deposits help to establish the episodes of progressive canyon cutting and to determine the routes of ancestral drainage, including the former position of the Wood River. As canyon cutting continued, springs began to emerge where lavas had filled the earlier canyons. When the Snake River canyon eventually attained its approximate present depth, the Wendell Grade Basalt erupted near Shoshone and, as several tongues, spread west to the canyon rim opposite Hagerman. One tongue crossed the future route of the Wood River, and another covered an upland area of Sand Springs Basalt that had previously reached the canyon floor at Hagerman. The McKinney Basalt then erupted from McKinney Butte northeast of Bliss and spread southward as a subaerial flow, covering part of the Wendell Grade Basalt. It filled the ancestral Wood River canyon and the Snake River canyon of that time west of Bliss as far downstream as King Hill. The resulting dam of lava impounded a deep lake, which extended upstream in the canyon beyond Hagerman. Copious amounts of the McKinney spilled into this temporary lake and produced pillow lava. About 2 miles west of Bliss, pillow lava 500 feet thick completely fills the former canyon and is protected by rimrock of the subaerial McKinney Basalt. From Bliss, the pillow facies extends upstream as far as the McKinney rimrock - about 5 miles. Eruption of the McKinney Basalt diverted the Wood River to a course along the southeast edge of this lava flow. The temporary lake that was dammed by McKinney Basalt west of Bliss spilled along the sou

Effects of roads and well pads on erosion in the Largo Canyon watershed, New Mexico, 2001-02

USGS Publications Warehouse

Matherne, Anne Marie

2006-01-01

Largo Canyon, located in the San Juan Basin of northwestern New Mexico, is one of the longest dry washes in the world. Oil and gas production in the San Juan Basin, which began in the 1940's, required the development of an extensive network of dirt roads to service the oil and gas wells in the Navajo Reservoir area. Presently, there are about eight wells per square mile, and the density of oil and gas wells is expected to increase. Potential environmental effects on landscape stability that may result from the additional roads and well pads have not been documented. In 2001, the U.S. Geological Survey began a study in cooperation with the Bureau of Land Management to evaluate the effects of roads and well pads associated with oil and gas operations on the erosion potential of Bureau of Land Management lands in the Largo Canyon watershed. The effects of roads and well pads on erosion were quantified by installing sediment dams (dams) and by surveying transects across roads and well pads. Data from 26 dams were used in the analysis. Dams were installed at 43 sites: 21 on hillsides upslope from roads or pads to measure erosion from hillslopes, 11 at the downslope edges of roads to measure erosion from roads, and 11 at the downslope edges of well pads to measure erosion from well pads. Pairs of survey transects were established at nine well pads and two road locations. Sediment-accumulation data for 26 dams, recorded at 17 measurement intervals, indicate that average erosion rates at the dams significantly correlate to size of the contributing area. The average erosion rate normalized by drainage area was 0.001 foot per year below roads, 0.003 foot per year on hillslopes, and 0.011 foot per year below well pads. Results of a two-sample t-test indicate that there was no significant difference in average erosion rates for dams located on hillslopes and below roads, whereas average erosion rates were significantly greater for dams below well pads than for dams on

The response of source-bordering aeolian dunefields to sediment-supply changes 2: Controlled floods of the Colorado River in Grand Canyon, Arizona, USA

USGS Publications Warehouse

Sankey, Joel B.; Caster, Joshua; Kasprak, Alan; East, Amy

2018-01-01

In the Colorado River downstream of Glen Canyon Dam in the Grand Canyon, USA, controlled floods are used to resupply sediment to, and rebuild, river sandbars that have eroded severely over the past five decades owing to dam-induced changes in river flow and sediment supply. In this study, we examine whether controlled floods, can in turn resupply aeolian sediment to some of the large source-bordering aeolian dunefields (SBDs) along the margins of the river. Using a legacy of high-resolution lidar remote-sensing and meteorological data, we characterize the response of four SBDs (a subset of 117 SBDs and other aeolian-sand-dominated areas in the canyon) during four sediment-laden controlled floods of the Colorado River in 2012, 2013, 2014, and 2016. We find that aeolian sediment resupply unambiguously occurred in 8 of the 16 instances of controlled flooding adjacent to SBDs. Resupply attributed to individual floods varied substantially among sites, and occurred with four, three, one, and zero floods at the four sites, respectively. We infer that the relative success of controlled floods as a regulated-river management tool for resupplying sediment to SBDs is analogous to the frequency of resupply observed for fluvial sandbars in this setting, in that sediment resupply was estimated to have occurred for roughly half of the instances of recent controlled flooding at sandbars monitored separately from this study. We find the methods developed in this, and a companion study, are effective tools to quantify geomorphic changes in sediment storage, along linked fluvial and aeolian pathways of sedimentary systems.

The response of source-bordering aeolian dunefields to sediment-supply changes 2: Controlled floods of the Colorado River in Grand Canyon, Arizona, USA

NASA Astrophysics Data System (ADS)

Sankey, Joel B.; Caster, Joshua; Kasprak, Alan; East, Amy E.

2018-06-01

In the Colorado River downstream of Glen Canyon Dam in the Grand Canyon, USA, controlled floods are used to resupply sediment to, and rebuild, river sandbars that have eroded severely over the past five decades owing to dam-induced changes in river flow and sediment supply. In this study, we examine whether controlled floods, can in turn resupply aeolian sediment to some of the large source-bordering aeolian dunefields (SBDs) along the margins of the river. Using a legacy of high-resolution lidar remote-sensing and meteorological data, we characterize the response of four SBDs (a subset of 117 SBDs and other aeolian-sand-dominated areas in the canyon) during four sediment-laden controlled floods of the Colorado River in 2012, 2013, 2014, and 2016. We find that aeolian sediment resupply unambiguously occurred in 8 of the 16 instances of controlled flooding adjacent to SBDs. Resupply attributed to individual floods varied substantially among sites, and occurred with four, three, one, and zero floods at the four sites, respectively. We infer that the relative success of controlled floods as a regulated-river management tool for resupplying sediment to SBDs is analogous to the frequency of resupply observed for fluvial sandbars in this setting, in that sediment resupply was estimated to have occurred for roughly half of the instances of recent controlled flooding at sandbars monitored separately from this study. We find the methods developed in this, and a companion study, are effective tools to quantify geomorphic changes in sediment storage, along linked fluvial and aeolian pathways of sedimentary systems.

Effects of Experimental High Flow Releases and Increased Fluctuations in Flow from Glen Canyon Dam on Abundance, Growth, and Survival Rates of Early Life Stages of Rainbow Trout in the Lee's Ferry Reach of the Colorado River

NASA Astrophysics Data System (ADS)

Korman, Josh

2010-05-01

The abundance of adult fish populations is controlled by the growth and survival rates of early life stages. Evaluating the effects of flow regimes on early life stages is therefore critical to determine how these regimes affect the abundance of adult populations. Experimental high flow releases from Glen Canyon Dam, primarily intended to conserve fine sediment and improve habitat conditions for native fish in the Colorado River in Grand Canyon, AZ, have been conducted in 1996, 2004, and 2008. These flows potentially affect the Lee's Ferry reach rainbow trout population, located immediately downstream of the dam, which supports a highly valued fishery and likely influences the abundance of rainbow trout in Grand Canyon. Due to concerns about negative effects of high trout abundance on endangered native fish, hourly variation in flow from Glen Canyon Dam was experimentally increased between 2003 and 2005 to reduce trout abundance. This study reports on the effects of experimental high flow releases and fluctuating flows on early life stages of rainbow trout in the Lee's Ferry reach based on monthly sampling of redds (egg nests) and the abundance and growth of age-0 trout between 2003 and 2009. Data on spawn timing, spawning elevations, and intergravel temperatures were integrated in a model to estimate the magnitude and seasonal trend in incubation mortality resulting from redd dewatering due to fluctuations in flow. Experimental fluctuations from January through March promoted spawning at higher elevations where the duration of dewatering was longer and intergravel temperatures exceeded lethal thresholds. Flow-dependent incubation mortality rates were 24% (2003) and 50% (2004) in years with higher flow fluctuations, compared to 5-11% under normal operations (2006-2009). Spatial and temporal predictions of mortality were consistent with direct observations of egg mortality determined from the excavation of 125 redds. The amount of variation in backcalculated hatch

Analysis of In-Canyon Flow Characterisitcs in step-up street canyons

NASA Astrophysics Data System (ADS)

PARK, S.; Kim, J.; Choi, W.; Pardyjak, E.

2017-12-01

Flow characteristics in strep-up street canyons were investigated focusing on in-canyon region. To see the effects of the building geometry, two building height ratios [ratio of the upwind (Hu) to downwind building heights (Hd) = 0.33, 0.6] were considered and eight building length ratios [ratio of the cross-wind building length (L) to street-canyon width (S) from 0.5 to 4 with the increment of 0.5] were systematically changed. For the model validation, the simulated results were compared with the wind- tunnel data measured for Hu/Hd = 0.33, 0.6 and L/S = 1, 2, 3, and 4. In the CFD model simulations, the corner vortices at the downwind side near the ground level and the recirculation zones above the downwind buildings had the relatively small extents, compared with those in the wind-tunnel experiments. However, the CFD model reproduced the main flow features such as the street-canyon vortices, circulations above the building roof, and the positions of the stagnation points on the downwind building walls in the wind-tunnel experiments reasonably well. By further analyzing the three-dimensional flow structures based on the numerical results simulated in the step-up street canyons, we schematically suggested the flow characteristics with different building-height and building-length ratios.

Non-native fish control below Glen Canyon Dam - Report from a structured decision-making project

USGS Publications Warehouse

Runge, Michael C.; Bean, Ellen; Smith, David; Kokos, Sonja

2011-01-01

This report describes the results of a structured decision-making project by the U.S. Geological Survey to provide substantive input to the Bureau of Reclamation (Reclamation) for use in the preparation of an Environmental Assessment concerning control of non-native fish below Glen Canyon Dam. A forum was created to allow the diverse cooperating agencies and Tribes to discuss, expand, and articulate their respective values; to develop and evaluate a broad set of potential control alternatives using the best available science; and to define individual preferences of each group on how to manage the inherent trade-offs in this non-native fish control problem. This project consisted of two face-to-face workshops, held in Mesa, Arizona, October 18-20 and November 8-10, 2010. At the first workshop, a diverse set of objectives was discussed, which represented the range of concerns of those agencies and Tribes present. A set of non-native fish control alternatives ('hybrid portfolios') was also developed. Over the 2-week period between the two workshops, four assessment teams worked to evaluate the control alternatives against the array of objectives. At the second workshop, the results of the assessment teams were presented. Multi-criteria decision analysis methods were used to examine the trade-offs inherent in the problem, and allowed the participating agencies and Tribes to express their individual judgments about how those trade-offs should best be managed in Reclamation`s selection of a preferred alternative. A broad array of objectives was identified and defined, and an effort was made to understand how these objectives are likely to be achieved by a variety of strategies. In general, the objectives reflected desired future conditions over 30 years. A rich set of alternative approaches was developed, and the complex structure of those alternatives was documented. Multi-criteria decision analysis methods allowed the evaluation of those alternatives against the array

Colorado River Vegetation, and Climate: Five Decades of Spatio-Temporal Dynamics in the Grand Canyon in Response to River Regulation

NASA Astrophysics Data System (ADS)

Ralston, B. E.; Sankey, J. B.

2013-12-01

Recent analysis of remotely sensed imagery of 400 km of the Colorado River confirms a net increase in vegetated area has occurred since the completion of Glen Canyon Dam in 1963. The rates and magnitude of vegetation change appear to be river stage-dependent. Riparian vegetation expansion on geomorphic surfaces at lower elevations relative to the river was greater for decades with lower peak and average discharges. Vegetation change at higher elevation relative to the river indicate that increases and decreases in vegetated area reflect regional precipitation patterns, and respectively coincide with regionally significant wet and dry periods that include the current early 21st century drought. The objective of this work was to examine the temporal persistence, and changes, in the spatial distribution of riparian vegetation relative to geomorphic characteristics of the Colorado River in Grand Canyon, dam and reservoir management, and regional climate over the 5-decade period from the mid-1960s to present. We employed archived riparian vegetation classifications that used aerial imagery from 1965, 1973, 1984, 1992, 2002, and 2009 coupled with flow regime data that is primarily related to operations of Glen Canyon Dam, field-measured rating relations, predictions of rating relations based on 1-D modeling, and detailed, geomorphic field mapping. Documentation of the effects of river regulation on riparian habitats in the SW USA has traditionally been limited to either small segments of river channels (e.g., 0.1-10km), or focused on specific plant species. The smaller geographic scale approach evaluates local hydrology, river channel changes, and serial recruitment events of riparian plants. The species-specific plant response informs larger scale patterns of riparian plant distributions across the landscape, but is less sensitive to differences of climate and hydrology among rivers. Our study is unique in that it employs datasets that allow both large-scale change

Carbon transport in Monterey Submarine Canyon

NASA Astrophysics Data System (ADS)

Barry, J.; Paull, C. K.; Xu, J. P.; Clare, M. A.; Gales, J. A.; Buck, K. R.; Lovera, C.; Gwiazda, R.; Maier, K. L.; McGann, M.; Parsons, D. R.; Simmons, S.; Rosenberger, K. J.; Talling, P. J.

2017-12-01

Submarine canyons are important conduits for sediment transport from continental margins to the abyss, but the rate, volume, and time scales of material transport have been measured only rarely. Using moorings with current meters, sediment traps (10 m above bottom) and optical backscatter sensors, we measured near-bottom currents, suspended sediment concentrations, and sediment properties at 1300 m depth in Monterey Canyon and at a non-canyon location on the continental slope at the same depth. Flow and water column backscatter were used to characterize "ambient" conditions when tidal currents dominated the flow field, and occasional "sediment transport events" when anomalously high down-canyon flow with sediment-laden waters arrived at the canyon mooring. The ambient sediment flux measured in sediment traps in Monterey Canyon was 350 times greater than measured at the non-canyon location. Although the organic carbon content of the canyon sediment flux during ambient periods was low (1.8 %C) compared to the slope location (4.9 %C), the ambient carbon transport in the canyon was 130 times greater than at the non-canyon site. Material fluxes during sediment transport events were difficult to measure owing to clogging of sediment traps, but minimal estimates indicate that mass transport during events exceeds ambient sediment fluxes through the canyon by nearly 3 orders of magnitude, while carbon transport is 380 times greater. Estimates of the instantaneous and cumulative flux of sediment and carbon from currents, backscatter, and sediment properties indicated that: 1) net flux is down-canyon, 2) flux is dominated by sediment transport events, and 3) organic carbon flux through 1300 m in Monterey Canyon was ca. 1500 MT C per year. The injection of 1500 MTCy-1 into the deep-sea represents ca. 260 km2 of the sediment C flux measured at the continental slope station (5.8 gCm-2y-1) and is sufficient to support a benthic community carbon demand of 5 gCm-2y-1 over 300 km2.

36 CFR 292.48 - Grazing activities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.48 Grazing activities. The... and located to minimize their impact on scenic, cultural, fish and wildlife, and other resources in... conditions which protect and conserve riparian areas. ...

2007 Weather and Aeolian Sand-Transport Data from the Colorado River Corridor, Grand Canyon, Arizona

USGS Publications Warehouse

Draut, Amy E.; Andrews, Timothy; Fairley, Helen C.; Brown, Christopher R.

2009-01-01

Weather data constitute an integral part of ecosystem monitoring in the Colorado River corridor and are particularly valuable for understanding processes of landscape change that contribute to the stability of archeological sites. Data collected in 2007 are reported from nine weather stations in the Colorado River corridor through Grand Canyon, Ariz. The stations were deployed in February and March 2007 to measure wind speed and direction, rainfall, air temperature, relative humidity, and barometric pressure. Sand traps near each weather station collect windblown sand, from which daily aeolian sand-transport rates are calculated. The data reported here were collected as part of an ongoing study to test and evaluate methods for quantifying processes that affect the physical integrity of archeological sites along the river corridor; as such, these data can be used to identify rainfall events capable of causing gully incision and to predict likely transport pathways for aeolian sand, two landscape processes integral to the preservation of archeological sites. Weather data also have widespread applications to other studies of physical, cultural, and biological resources in Grand Canyon. Aeolian sand-transport data reported here, collected in the year before the March 2008 High-Flow Experiment (HFE) at Glen Canyon Dam, represent baseline data against which the effects of the 2008 HFE on windblown sand will be compared in future reports.

Strategic guidelines for street canyon geometry to achieve sustainable street air quality—part II: multiple canopies and canyons

NASA Astrophysics Data System (ADS)

Chan, Andy T.; Au, William T. W.; So, Ellen S. P.

The flow field and pollutant dispersion characteristics in a three-dimensional urban street canyon are investigated for various building array geometries. The street canyon in consideration is located in a multi-canopy building array that is similar to realistic estate situations. The pollutant dispersion characteristics are studied for various canopy aspect ratios, namely: the canyon height to width ratio, canyon length to height ratio, canyon breadth ratio and crossroad locations are studied. A three-dimensional field-size canyon has been analysed through numerical simulations using k- ɛ turbulence model. As expected, the wind flow and mode of pollutant dispersion is strongly dependent on the various flow geometric configurations and that the results can be different from that of a single canyon system. For example, it is found that the pollutant retention value is minimum when the canyon height-to-width ratio is approximately 0.8, or that the building height ratio is 0.5. Various rules of thumbs on urban canyon geometry have been established for good pollutant dispersion.

Ecological Functioning in Two Mid-Atlantic Bight Submarine Canyons: Macrofauna Community Trends and the Role of Canyon Specific Processes

NASA Astrophysics Data System (ADS)

Robertson, C.; Bourque, J. R.; Davies, A. J.; Duineveld, G.; Mienis, F.; Brooke, S.; Ross, S. W.; Demopoulos, A. W.

2016-02-01

Submarine canyons are complex systems, acting as major conduits of organic matter along continental shelves and promoting gradients in food resources, turbidity flows, habitat heterogeneity, and areas of sediment resuspension and deposition. In the western North Atlantic, a large multidisciplinary program was conducted in two major Mid-Atlantic Bight (MAB) canyons (Baltimore and Norfolk canyons). This Atlantic Deepwater Canyons project was funded by BOEM, NOAA, and USGS. Here we investigate the `canyon effect' on benthic ecosystem ecology and functioning of two canyon systems by defining canyon specific processes influencing MAB shelf benthic community trends. Sediment cores were collected in 2012 and 2013 with a NIOZ box corer along the main axes ( 180-1200m) of Baltimore and Norfolk Canyon and at comparable depths on the adjacent continental slope. Whole community macrofaunal (>300 μm) abundance and biomass data provided insight into community trends across depth and biogeochemical gradients by coupling diversity metrics and biological trait analyses with sediment biogeochemistry and hydrodynamic data. The canyons exhibited clear differences in sediment profiles, hydrodynamic regimes and enrichment depocenters as well as significantly distinct infauna communities. Interestingly, both canyons showed bimodal distributions in abundances and diversity of infauna and a shallowing of species maxima which was not present on adjacent slopes. We hypothesize that physical canyon processes are important regulators in the depth of observed species maxima and community functioning on the MAB shelf, on local and regional scales. Unique sediment dynamics, organic enrichment, and hydrographic conditions were significant factors in structuring benthic community differences in MAB canyons The study provides a complete benthic infaunal appraisal of two canyon systems in the western Atlantic, incorporating biogeochemistry and oceanography to increase our understanding of canyon

Formative flow in bedrock canyons

NASA Astrophysics Data System (ADS)

Venditti, J. G.; Kwoll, E.; Rennie, C. D.; Church, M. A.

2017-12-01

In alluvial channels, it is widely accepted that river channel configuration is set by a formative flow that represents a balance between the magnitude and frequency of flood flows. The formative flow is often considered to be one that is just capable of filling a river channel to the top of its banks. Flows much above this formative flow are thought to cause substantial sediment transport and rearrange the channel morphology to accommodate the larger flow. This idea has recently been extended to semi-alluvial channels where it has been shown that even with bedrock exposed, the flows rarely exceed that required to entrain the local sediment cover. What constitutes a formative flow in a bedrock canyon is not clear. By definition, canyons have rock walls and are typically incised vertically, removing the possibility of the walls being overtopped, as can occur in an alluvial channel at high flows. Canyons are laterally constrained, have deep scour pools and often have width to maximum depth ratios approaching 1, an order of magnitude lower than alluvial channels. In many canyons, there are a sequence of irregularly spaced scour pools. The bed may have intermittent or seasonal sediment cover, but during flood flows the sediment bed is entrained leaving a bare bedrock channel. It has been suggested that canyons cut into weak, well-jointed rock may adjust their morphology to the threshold for block plucking because the rock bed is labile during exceptionally large magnitude flows. However, this hypothesis does not apply to canyons cut into massive crystalline rock where abrasion is the dominant erosion process. Here, we argue that bedrock canyon morphology is adjusted to a characteristic flow structure developed in bedrock canyons. We show that the deeply scoured canyon floor is adjusted to a velocity inversion that is present at low flows, but gets stronger at high flows. The effect is to increase boundary shear stresses along the scour pool that forms in constricted

Let's Bet on Sediments! Hudson Canyon Cruise--Grades 9-12. Focus: Sediments of Hudson Canyon.

ERIC Educational Resources Information Center

National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

These activities are designed to teach about the sediments of Hudson Canyon. Students investigate and analyze the patterns of sedimentation in the Hudson Canyon, observe how heavier particles sink faster than finer particles, and learn that submarine landslides are avalanches of sediment in deep ocean canyons. The activity provides learning…

Geologic map and profiles of the north wall of the Snake River Canyon, Thousand Springs and Niagara quadrangles, Idaho

USGS Publications Warehouse

Covington, H.R.; Weaver, Jean N.

1991-01-01

The Snake River Plain is a broad, arcuate region of low relief that extends more than 300 mi across southern Idaho. The Snake River enters the plain near Idaho Falls and flows westward along the southern margin of the eastern Snake River Plain (fig. 1), a position mainly determined by the basaltic lava flows that erupted near the axis of the plain. The highly productive Snake River Plain aquifer north of the Snake River underlies most of the eastern plain. The aquifer is composed of basaltic rocks that are interbedded with fluvial and lacustrine sedimentary rocks. The top of the aquifer (water table) is typically less than 500 ft below the land surface but is deeper than 1,000 ft in a few areas. The Snake River has excavated a canyon into the nearly flat lying basaltic and sedimentary rocks of the eastern Snake River Plain aquifer, which discharges from the northern canyon wall as springs of variable size, spacing, and altitude. Geologic controls on springs are of importance because nearly 60 percent of the aquifer's discharge occurs as spring flow along the describes the geologic occurrence of springs along the northern wall of the Snake River canyon. This report is one of several that describes the geologic occurrence of springs along the northern wall of the Snake River canyon from Milner Dam to King Hill. To understand the local geologic controls on springs, the Water Resources Division of the U.S. Geological Survey initiated a geologic mapping project as part of their Snake River Plain Regional Aquifer System-Analysis Program. Objectives of the project were (1) to prepare a geologic map of a strip of land immediately north of the Snake River canyon, (2) to map the geology of the north canyon wall in profile, (3) to locate spring occurrences along the north side of the Snake River between Milner Sam and King Hill, and (4) to estimate spring discharge from the north wall of the canyon.

106. DAM EARTH DIKE SUBMERSIBLE DAMS & DIKE ...

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

106. DAM - EARTH DIKE - SUBMERSIBLE DAMS & DIKE CONN. AT MOVABLE DAM (ML-8-52/2-FS) March 1940 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

DAM Safety and Deformation Monitoring in Dams

NASA Astrophysics Data System (ADS)

Kalkan, Y.; Bilgi, S.; Potts, L.; Miiama, J.; Mahgoub, M.; Rahman, S.

2013-12-01

Water is the life and necessity to water is increasing day by day with respect to the World population, rising of living standards and destruction of nature. Thus, the importance of water and water structures have been increasing gradually. Dams are among the most important engineering structures used for water supplies, flood controls, agricultural purposes as well as drinking and hydroelectric power. There are about 150.000 large size dams in the World. Especially after the Second World War, higher and larger capacity dams have been constructed. Dams create certain risks like the other manmade structures. No one knows precisely how many dam failures have occurred in the World, whereas hundreds of dam failures have occurred throughout the U.S. history. Some basic physical data are very important for assessing the safety and performance of dams. These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. These physical data are measured and monitored by the instruments and equipment. Dams and their surroundings have to be monitored by using essential methods at periodic time intervals in order to determine the possible changes that may occur over the time. Monitoring programs typically consist of; surveillance or visual observation. These programs on dams provide information for evaluating the dam's performance related to the design intent and expected changes that could affect the safety performance of the dam. Additionally, these programs are used for investigating and evaluating the abnormal or degrading performance where any remedial action is necessary. Geodetic and non-geodetic methods are used for monitoring. Monitoring the performance of the dams is critical for producing and maintaining the safe dams. This study provides some information, safety and the techniques about the deformation monitoring of the

Wintertime Boundary Layer Structure in the Grand Canyon.

NASA Astrophysics Data System (ADS)

Whiteman, C. David; Zhong, Shiyuan; Bian, Xindi

1999-08-01

Wintertime temperature profiles in the Grand Canyon exhibit a neutral to isothermal stratification during both daytime and nighttime, with only rare instances of actual temperature inversions. The canyon warms during daytime and cools during nighttime more or less uniformly through the canyon's entire depth. This weak stability and temperature structure evolution differ from other Rocky Mountain valleys, which develop strong nocturnal inversions and exhibit convective and stable boundary layers that grow upward from the valley floor. Mechanisms that may be responsible for the different behavior of the Grand Canyon are discussed, including the possibility that the canyon atmosphere is frequently mixed to near-neutral stratification when cold air drains into the top of the canyon from the nearby snow-covered Kaibab Plateau. Another feature of canyon temperature profiles is the sharp inversions that often form near the canyon rims. These are generally produced when warm air is advected over the canyon in advance of passing synoptic-scale ridges.Wintertime winds in the main canyon are not classical diurnal along-valley wind systems. Rather, they are driven along the canyon axis by the horizontal synoptic-scale pressure gradient that is superimposed along the canyon's axis by passing synoptic-scale weather disturbances. They may thus bring winds into the canyon from either end at any time of day.The implications of the observed canyon boundary layer structure for air pollution dispersion are discussed.

Application of sedimentary-structure interpretation to geoarchaeological investigations in the Colorado River Corridor, Grand Canyon, Arizona, USA

USGS Publications Warehouse

Draut, A.E.; Rubin, D.M.; Dierker, J.L.; Fairley, H.C.; Griffiths, R.E.; Hazel, J.E.; Hunter, R.E.; Kohl, K.; Leap, L.M.; Nials, F.L.; Topping, D.J.; Yeatts, M.

2008-01-01

We present a detailed geoarchaeological study of landscape processes that affected prehistoric formation and modern preservation of archaeological sites in three areas of the Colorado River corridor in Grand Canyon, Arizona, USA. The methods used in this case study can be applied to any locality containing unaltered, non-pedogenic sediments and, thus, are particularly relevant to geoarchaeology in arid regions. Resolving the interaction of fluvial, aeolian, and local runoff processes in an arid-land river corridor is important because the archaeological record in arid lands tends to be concentrated along river corridors. This study uses sedimentary structures and particle-size distributions to interpret landscape processes; these methods are commonplace in sedimentology but prove also to be valuable, though less utilized, in geoarchaeology and geomorphology. In this bedrock canyon, the proportion of fluvial sediment generally decreases with distance away from the river as aeolian, slope-wash, colluvial, and debris-flow sediments become more dominant. We describe a new facies consisting of 'flood couplets' that include a lower, fine-grained fluvial component and an upper, coarser, unit that reflects subaerial reworking at the land surface between flood events. Grain-size distributions of strata that lack original sedimentary structures are useful within this river corridor to distinguish aeolian deposits from finer-grained fluvial deposits that pre-date the influence of the upstream Glen Canyon Dam on the Colorado River. Identification of past geomorphic settings is critical for understanding the history and preservation of archaeologically significant areas, and for determining the sensitivity of archaeological sites to dam operations. Most archaeological sites in the areas studied were formed on fluvial deposits, with aeolian deposition acting as an important preservation agent during the past millennium. Therefore, the absence of sediment-rich floods in this

With Dante in Hell on 9/11: "That Day We Read No Further"

ERIC Educational Resources Information Center

Rosenstein, Roy

2015-01-01

In this article, Roy Rosenstein shares the events that occurred during his first day of teaching the Dante and Medieval Culture course in the fall semester of 2001 at the American University of Paris (AUP). On, September 11, 2001, immediately following Rosenstein's opening statement of "Welcome to hell," the class was alerted to the…

Seismically induced rock slope failures resulting from topographic amplification of strong ground motions: The case of Pacoima Canyon, California

USGS Publications Warehouse

Sepulveda, S.A.; Murphy, W.; Jibson, R.W.; Petley, D.N.

2005-01-01

The 1994 Northridge earthquake (Mw = 6.7) triggered extensive rock slope failures in Pacoima Canyon, immediately north of Los Angeles, California. Pacoima Canyon is a narrow and steep canyon incised in gneissic and granitic rocks. Peak accelerations of nearly 1.6 g were recorded at a ridge that forms the left abutment of Pacoima Dam; peak accelerations at the bottom of the canyon were less than 0.5 g, suggesting the occurrence of topographic amplification. Topographic effects have been previously suggested to explain similarly high ground motions at the site during the 1971 (Mw = 6.7) San Fernando earthquake. Furthermore, high landslide concentrations observed in the area have been attributed to unusually strong ground motions rather than higher susceptibility to sliding compared with nearby zones. We conducted field investigations and slope stability back-analyses to confirm the impact of topographic amplification on the triggering of landslides during the 1994 earthquake. Our results suggest that the observed extensive rock sliding and falling would have not been possible under unamplified seismic conditions, which would have generated a significantly lower number of areas affected by landslides. In contrast, modelling slope stability using amplified ground shaking predicts slope failure distributions matching what occurred in 1994. This observation confirms a significant role for topographic amplification on the triggering of landslides at the site, and emphasises the need to select carefully the inputs for seismic slope stability analyses. ?? 2005 Elsevier B.V. All rights reserved.

78 FR 48670 - Boulder Canyon Project

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-09

... DEPARTMENT OF ENERGY Western Area Power Administration Boulder Canyon Project AGENCY: Western Area... Canyon Project (BCP) electric service provided by the Western Area Power Administration (Western). The... States Department of Energy, Western Area Power Administration, Boulder Canyon Project, 133 FERC ] 62,229...

Street canyon aerosol pollutant transport measurements.

PubMed

Longley, I D; Gallagher, M W; Dorsey, J R; Flynn, M; Bower, K N; Allan, J D

2004-12-01

Current understanding of dispersion in street canyons is largely derived from relatively simple dispersion models. Such models are increasingly used in planning and regulation capacities but are based upon a limited understanding of the transport of substances within a real canyon. In recent years, some efforts have been made to numerically model localised flow in idealised canyons (e.g., J. Appl. Meteorol. 38 (1999) 1576-89) and stepped canyons (Assimakopoulos V. Numerical modelling of dispersion of atmospheric pollution in and above urban canopies. PhD thesis, Imperial College, London, 2001) but field studies in real canyons are rare. To further such an understanding, a measurement campaign has been conducted in an asymmetric street canyon with busy one-way traffic in central Manchester in northern England. The eddy correlation method was used to determine fluxes of size-segregated accumulation mode aerosol. Measurements of aerosol at a static location were made concurrently with measurements on a platform lift giving vertical profiles. Size-segregated measurements of ultrafine and coarse particle concentrations were also made simultaneously at various heights. In addition, a small mobile system was used to make measurements of turbulence at various pavement locations within the canyon. From this data, various features of turbulent transport and dispersion in the canyon will be presented. The concentration and the ventilation fluxes of vehicle-related aerosol pollutants from the canyon will be related to controlling factors. The results will also be compared with citywide ventilation data from a separate measurement campaign conducted above the urban canopy.

Transient simulation of groundwater levels within a sandbar of the Colorado River, Marble Canyon, Arizona, 2004

USGS Publications Warehouse

Sabol, Thomas A.; Springer, Abraham E.

2013-01-01

Seepage erosion and mass failure of emergent sandy deposits along the Colorado River in Grand Canyon National Park, Arizona, are a function of the elevation of groundwater in the sandbar, fluctuations in river stage, the exfiltration of water from the bar face, and the slope of the bar face. In this study, a generalized three-dimensional numerical model was developed to predict the time-varying groundwater level, within the bar face region of a freshly deposited eddy sandbar, as a function of river stage. Model verification from two transient simulations demonstrates the ability of the model to predict groundwater levels within the onshore portion of the sandbar face across a range of conditions. Use of this generalized model is applicable across a range of typical eddy sandbar deposits in diverse settings. The ability to predict the groundwater level at the onshore end of the sandbar face is essential for both physical and numerical modeling efforts focusing on the erosion and mass failure of eddy sandbars downstream of Glen Canyon Dam along the Colorado River.

Durable terrestrial bedrock predicts submarine canyon formation

USGS Publications Warehouse

Smith, Elliot; Finnegan, Noah J.; Mueller, Erich R.; Best, Rebecca J.

2017-01-01

Though submarine canyons are first-order topographic features of Earth, the processes responsible for their occurrence remain poorly understood. Potentially analogous studies of terrestrial rivers show that the flux and caliber of transported bedload are significant controls on bedrock incision. Here we hypothesize that coarse sediment load could exert a similar role in the formation of submarine canyons. We conducted a comprehensive empirical analysis of canyon occurrence along the West Coast of the contiguous United States which indicates that submarine canyon occurrence is best predicted by the occurrence of durable crystalline bedrock in adjacent terrestrial catchments. Canyon occurrence is also predicted by the flux of bed sediment to shore from terrestrial streams. Surprisingly, no significant correlation was observed between canyon occurrence and the slope or width of the continental shelf. These findings suggest that canyon incision is promoted by greater yields of durable terrestrial clasts to the shore.

Morphology, distribution, and development of submarine canyons on the United States Atlantic continental slope between Hudson arid Baltimore Canyons

NASA Astrophysics Data System (ADS)

Twichell, David C.; Roberts, David G.

1982-08-01

The distribution and morphology of submarine canyons off the eastern United States between Hudson and Baltimore Canyons have been mapped by long-range sidescan sonar. In this area canyons are numerous, and their spacing correlates with overall slope gradient; they are absent where the gradient is less than 3°, are 2 to 10 km apart where the gradient is 3° to 5°, and are 1.5 to 4 km apart where the gradient exceeds 6°. Canyons range from straight to sinuous; those having sinuous axes indent the edge of the continental shelf and appear to be older than those that head on the upper slope and have straighter axes. A difference in canyon age would suggest that canyons are initiated on the continental slope and only with greater age erode headward to indent the shelf. Shallow gullies on the middle and upper slope parts of the canyon walls suggest that submarine erosion has been a major process in a recent phase of canyon development. *Present address: British Petroleum, Moorgate, London EC2Y 9BU, England

Mineral resources of the Fish Creek Canyon, Road Canyon, and Mule Canyon Wilderness Study Areas, San Juan County, Utah

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

Bove, D.J.; Shawe, D.R.; Lee, G.K.

1989-01-01

This book reports the Fish Creek Canyon (UT-060-204), Road Canyon(UT-060-201), and Mule Canyon (UT-060-205B) Wilderness Study Areas, which comprise 40,160 acres, 52,420 acres, and 5,990 acres, respectively, studied for their mineral endowment. A search of federal, state, and county records showed no current or previous mining-claim activity. No mineral resources were identified during field examination of the study areas. Sandstone and sand and gravel have no unique qualities but could have limited local use for road metal or other construction purposes. However, similar materials are abundant outside the study areas. The three study areas have moderate resource potential for undiscoveredmore » oil and gas and low resource potential for undiscovered metals, including uranium and thorium, coal, and geothermal energy.« less

Ephemeral seafloor sedimentation during dam removal: Elwha River, Washington

USGS Publications Warehouse

Foley, Melissa M.; Warrick, Jonathan

2017-01-01

The removal of the Elwha and Glines Canyon dams from the Elwha River in Washington, USA, resulted in the erosion and transport of over 10 million m3 of sediment from the former reservoirs and into the river during the first two years of the dam removal process. Approximately 90% of this sediment was transported through the Elwha River and to the coast at the Strait of Juan de Fuca. To evaluate the benthic dynamics of increased sediment loading to the nearshore, we deployed a tripod system in ten meters of water to the east of the Elwha River mouth that included a profiling current meter and a camera system. With these data, we were able to document the frequency and duration of sedimentation and turbidity events, and correlate these events to physical oceanographic and river conditions. We found that seafloor sedimentation occurred regularly during the heaviest sediment loading from the river, but that this sedimentation was ephemeral and exhibited regular cycles of deposition and erosion caused by the strong tidal currents in the region. Understanding the frequency and duration of short-term sediment disturbance events is instrumental to interpreting the ecosystem-wide changes that are occurring in the nearshore habitats around the Elwha River delta.

Ephemeral seafloor sedimentation during dam removal: Elwha River, Washington

NASA Astrophysics Data System (ADS)

Foley, Melissa M.; Warrick, Jonathan A.

2017-11-01

The removal of the Elwha and Glines Canyon dams from the Elwha River in Washington, USA, resulted in the erosion and transport of over 10 million m3 of sediment from the former reservoirs and into the river during the first two years of the dam removal process. Approximately 90% of this sediment was transported through the Elwha River and to the coast at the Strait of Juan de Fuca. To evaluate the benthic dynamics of increased sediment loading to the nearshore, we deployed a tripod system in ten meters of water to the east of the Elwha River mouth that included a profiling current meter and a camera system. With these data, we were able to document the frequency and duration of sedimentation and turbidity events, and correlate these events to physical oceanographic and river conditions. We found that seafloor sedimentation occurred regularly during the heaviest sediment loading from the river, but that this sedimentation was ephemeral and exhibited regular cycles of deposition and erosion caused by the strong tidal currents in the region. Understanding the frequency and duration of short-term sediment disturbance events is instrumental to interpreting the ecosystem-wide changes that are occurring in the nearshore habitats around the Elwha River delta.

Mars Canyon with Los Angeles for Scale

NASA Image and Video Library

2006-03-13

A Grand Canyon of Mars slices across the Red Planet near its equator. This canyon -- Valles Marineris, or the Mariner Valley -- is 10 times longer and deeper than Arizona Grand Canyon, and 20 times wider

Environmental assessment: Davis Canyon site, Utah

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

none,

1986-05-01

In February 1983, the US Department of Energy (DOE) identified the Davis Canyon site in Utah as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Davis Canyon site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOEmore » prepared the final EA. The Davis Canyon site is in the Paradox Basin, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains one other potentially acceptable site -- the Lavender Canyon site. Although the Lavender Canyon site is suitable for site characterization, the DOE has concluded that the Davis Canyon site is the preferred site in the Paradox Basin. On the basis of the evaluations reported in this EA, the DOE has found that the Davis Canyon site is not disqualified under the guidelines. Furthermore, the DOE has fond that the site is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is nominating the Davis Canyon site as one of five sites suitable for characterization. 181 figs., 175 tabs.« less

Environmental assessment: Davis Canyon site, Utah

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

none,

1986-05-01

In February 1983, the US Department of Energy (DOE) identified the Davis Canyon site in Utah as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high- level radioactive waste. To determine their suitability, the Davis Canyon site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, themore » DOE prepared the final EA. The Davis Canyon site is in the Paradox Basin, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains one other potentially acceptable site -- the Lavender Canyon site. Although the Lavender Canyon site is suitable for site characterization, the DOE has concluded that the Davis Canyon site is the preferred site in the Paradox Basin. On the basis of the evaluations reported in this EA, the DOE has found that the Davis Canyon site is not disqualified under the guidelines. Furthermore, the DOE has found that the site is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is nominating the Davis Canyon site as one of the five sites suitable for characterization.« less

Environmental assessment: Davis Canyon site, Utah

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

none,

1986-05-01

In February 1983, the US Department of Energy (DOE) identified the Davis Canyon site in Utah as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Davis Canyon site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOEmore » prepared the final EA. The Davis Canyon site is in the Paradox Basin, which is one of five distinct geohydrologic settings considering for the first repository. This setting contains one other potentially acceptable site -- the Lavender Canyon site. Although the Lavender Canyon site is suitable for site characterization, the DOE has concluded that the Davis Canyon site is the preferred site in the Paradox Basin. On the basis of the evaluations reported in this EA, the DOE has found that the Davis Canyon site is not disqualified under the guidelines. Furthermore, the DOE has found that the site is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is nominating the Davis Canyon site as one of five sites suitable for characterization.« less

107. DAM EARTH DIKE SUBMERSIBLE DAMS PLANS ...

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

107. DAM - EARTH DIKE - SUBMERSIBLE DAMS - PLANS & SECTIONS (ML-8-52/3-FS) March 1940 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

Riparian vegetation, Colorado River, and climate: five decades of spatiotemporal dynamics in the Grand Canyon with river regulation

USGS Publications Warehouse

Sankey, Joel B.; Ralston, Barbara E.; Grams, Paul E.; Schmidt, John C.; Cagney, Laura E.

2015-01-01

Documentation of the interacting effects of river regulation and climate on riparian vegetation has typically been limited to small segments of rivers or focused on individual plant species. We examine spatiotemporal variability in riparian vegetation for the Colorado River in Grand Canyon relative to river regulation and climate, over the five decades since completion of the upstream Glen Canyon Dam in 1963. Long-term changes along this highly modified, large segment of the river provide insights for management of similar riparian ecosystems around the world. We analyze vegetation extent based on maps and imagery from eight dates between 1965 and 2009, coupled with the instantaneous hydrograph for the entire period. Analysis confirms a net increase in vegetated area since completion of the dam. Magnitude and timing of such vegetation changes are river stage-dependent. Vegetation expansion is coincident with inundation frequency changes and is unlikely to occur for time periods when inundation frequency exceeds approximately 5%. Vegetation expansion at lower zones of the riparian area is greater during the periods with lower peak and higher base flows, while vegetation at higher zones couples with precipitation patterns and decreases during drought. Short pulses of high flow, such as the controlled floods of the Colorado River in 1996, 2004, and 2008, do not keep vegetation from expanding onto bare sand habitat. Management intended to promote resilience of riparian vegetation must contend with communities that are sensitive to the interacting effects of altered flood regimes and water availability from river and precipitation.

Riparian vegetation, Colorado River, and climate: Five decades of spatiotemporal dynamics in the Grand Canyon with river regulation

NASA Astrophysics Data System (ADS)

Sankey, Joel B.; Ralston, Barbara E.; Grams, Paul E.; Schmidt, John C.; Cagney, Laura E.

2015-08-01

Documentation of the interacting effects of river regulation and climate on riparian vegetation has typically been limited to small segments of rivers or focused on individual plant species. We examine spatiotemporal variability in riparian vegetation for the Colorado River in Grand Canyon relative to river regulation and climate, over the five decades since completion of the upstream Glen Canyon Dam in 1963. Long-term changes along this highly modified, large segment of the river provide insights for management of similar riparian ecosystems around the world. We analyze vegetation extent based on maps and imagery from eight dates between 1965 and 2009, coupled with the instantaneous hydrograph for the entire period. Analysis confirms a net increase in vegetated area since completion of the dam. Magnitude and timing of such vegetation changes are river stage-dependent. Vegetation expansion is coincident with inundation frequency changes and is unlikely to occur for time periods when inundation frequency exceeds approximately 5%. Vegetation expansion at lower zones of the riparian area is greater during the periods with lower peak and higher base flows, while vegetation at higher zones couples with precipitation patterns and decreases during drought. Short pulses of high flow, such as the controlled floods of the Colorado River in 1996, 2004, and 2008, do not keep vegetation from expanding onto bare sand habitat. Management intended to promote resilience of riparian vegetation must contend with communities that are sensitive to the interacting effects of altered flood regimes and water availability from river and precipitation.

Hanging canyons of Haida Gwaii, British Columbia, Canada: Fault-control on submarine canyon geomorphology along active continental margins

NASA Astrophysics Data System (ADS)

Harris, Peter T.; Barrie, J. Vaughn; Conway, Kim W.; Greene, H. Gary

2014-06-01

Faulting commonly influences the geomorphology of submarine canyons that occur on active continental margins. Here, we examine the geomorphology of canyons located on the continental margin off Haida Gwaii, British Columbia, that are truncated on the mid-slope (1200-1400 m water depth) by the Queen Charlotte Fault Zone (QCFZ). The QCFZ is an oblique strike-slip fault zone that has rates of lateral motion of around 50-60 mm/yr and a small convergent component equal to about 3 mm/yr. Slow subduction along the Cascadia Subduction Zone has accreted a prism of marine sediment against the lower slope (1500-3500 m water depth), forming the Queen Charlotte Terrace, which blocks the mouths of submarine canyons formed on the upper slope (200-1400 m water depth). Consequently, canyons along this margin are short (4-8 km in length), closely spaced (around 800 m), and terminate uniformly along the 1400 m isobath, coinciding with the primary fault trend of the QCFZ. Vertical displacement along the fault has resulted in hanging canyons occurring locally. The Haida Gwaii canyons are compared and contrasted with the Sur Canyon system, located to the south of Monterey Bay, California, on a transform margin, which is not blocked by any accretionary prism, and where canyons thus extend to 4000 m depth, across the full breadth of the slope.

Hydrogeology of Middle Canyon, Oquirrh Mountains, Tooele County, Utah

USGS Publications Warehouse

Gates, Joseph Spencer

1963-01-01

Geology and climate are the principal influences affecting the hydrology of Middle Canyon, Tooele County, Utah. Reconnaissance in the canyon indicated that the geologic influences on the hydrology may be localized; water may be leaking through fault and fracture zones or joints in sandstone and through solution openings in limestone of the Oquirrh formation of Pennsylvanian and Permian age. Surficial deposits of Quaternary age serve as the main storage material for ground water in the canyon and transmit water from the upper canyon to springs and drains at the canyon mouth. The upper canyon is a more important storage area than the lower canyon because the surficial deposits are thicker, and any zones of leakage in the underlying bedrock of the upper canyon probably would result in greater leakage than would similar outlets in the lower canyon.The total annual discharge from Middle Canyon, per unit of precipitation, decreased between 1910 and 1939. Similar decreases occurred in Parleys Canyon in the nearby Wasatch Range and in other drainage basins in Utah, and it is likely that most of the decrease in discharge from Middle Canyon and other canyons in Utah is due to a change in climate.Chemical analyses of water showed that the high content of sulfate and other constituents in the water from the Utah Metals tunnel, which drains into Middle Canyon, does not have a significant effect on water quality at the canyon mouth. This suggests that much of the tunnel water is lost from the channel by leakage, probably in the upper canyon, during the dry part of the year.Comparison of the 150 acre-feet of water per square mile of drainage area discharged by Middle Canyon in 1947 with the 623 and 543 acre-feet per square mile discharged in 1948 by City Creek and Mill Creek Canyons, two comparable drainage basins in the nearby Wasatch Range, also suggests that there is leakage in Middle Canyon.A hydrologic budget of the drainage basin results in an estimate that about 3,000 acre

Politicians, Patriots and Plotters: Unlikely Debates Occasioned by Maximilian Hell's Venus Transit Expedition of 1769

NASA Astrophysics Data System (ADS)

Kontler, Laszlo

2013-05-01

This paper discusses the cultural and political contexts and reception of the most important by-product of Maximilian Hell's famous Venus transit expedition of 1768-69, the Demonstratio. Idioma Ungarorum et Lapponum idem esse (1770) by Hell's associate Janos Sajnovics. Now considered a landmark in Finno-Ugrian linguistics, the Demonstratio addressed an academic subject that was at that time almost destined to be caught up in an ideological battlefield defined by the shifting relationship between the Habsburg government, the Society of Jesus, and the Hungarian nobility. The "enlightened absolutist" policies of the former aimed at consolidating the Habsburg monarchy as an empire, at the expense of privileged groups, including religious orders as well as the noble estates. In the situation created by the 1773 suppression of the Jesuit order (a signal of declining patronage from the dynasty), the growing preoccupation on the part of ex-Jesuits like Hell and Sajnovics with "things Hungarian" could have been part of an attempt to re-situate themselves on the Central European map of learning. At the same time, the founding document of this interest, the Demonstratio, evoked violent protests from the other target of Habsburg policies, the Hungarian nobility, because its basic assumptions - the kinship of the Hungarian and the Sami (Lappian) language - potentially undermined the noble ideology of social exclusiveness, established on the alleged "Scythian" ancestry of Hungarians. By exploring the complex motives, intentions, reactions and responses of the chief agents in this story, it is possible to highlight the extra-scientific constraints and facilitators for the practice of knowledge in late eighteenth century Central Europe.

Late Holocene earthquake history of the Brigham City segment of the Wasatch fault zone at the Hansen Canyon, Kotter Canyon, and Pearsons Canyon trench sites, Box Elder County, Utah

USGS Publications Warehouse

DuRoss, Christopher B.; Personius, Stephen F.; Crone, Anthony J.; McDonald, Greg N.; Briggs, Richard W.

2012-01-01

Of the five central segments of the Wasatch fault zone (WFZ) having evidence of recurrent Holocene surface-faulting earthquakes, the Brigham City segment (BCS) has the longest elapsed time since its most recent surface-faulting event (~2.1 kyr) compared to its mean recurrence time between events (~1.3 kyr). Thus, the BCS has the highest time-dependent earthquake probability of the central WFZ. We excavated trenches at three sites––the Kotter Canyon and Hansen Canyon sites on the north-central BCS and Pearsons Canyon site on the southern BCS––to determine whether a surface-faulting earthquake younger than 2.1 ka occurred on the BCS. Paleoseismic data for Hansen Canyon and Kotter Canyon confirm that the youngest earthquake on the north-central BCS occurred before 2 ka, consistent with previous north-central BCS investigations at Bowden Canyon and Box Elder Canyon. At Hansen Canyon, the most recent earthquake is constrained to 2.1–4.2 ka and had 0.6–2.5 m of vertical displacement. At Kotter Canyon, we found evidence for two events at 2.5 ± 0.3 ka and 3.5 ± 0.3 ka, with an average displacement per event of 1.9–2.3 m. Paleoseismic data from Pearsons Canyon, on the previously unstudied southern BCS, indicate that a post-2 ka earthquake ruptured this part of the segment. The Pearsons Canyon earthquake occurred at 1.2 ± 0.04 ka and had 0.1–0.8 m of vertical displacement, consistent with our observation of continuous, youthful scarps on the southern 9 km of the BCS having 1–2 m of late Holocene(?) surface offset. The 1.2-ka earthquake on the southern BCS likely represents rupture across the Weber–Brigham City segment boundary from the penultimate Weber-segment earthquake at about 1.1 ka. The Pearsons Canyon data result in a revised length of the BCS that has not ruptured since 2 ka (with time-dependent probability implications), and provide compelling evidence of at least one segment-boundary failure and multi-segment rupture on the central WFZ. Our

Sediment connectivity at source-bordering aeolian dunefields along the Colorado River in the Grand Canyon, USA

NASA Astrophysics Data System (ADS)

Sankey, Joel; Kasprak, Alan; Caster, Joshua; East, Amy; Fairley, Helen

2017-04-01

Aeolian dunefields that are primarily built and maintained with river-derived sediment are found in many river valleys throughout the world and are impacted by changes in climate, land use, and river regulation. Quantifying the dynamic response of these aeolian dunefields to alterations in river flow is especially difficult given the highly correlated nature of the interacting geomorphic and sediment transport processes that drive their formation and maintenance. We characterize the effects of controlled river floods on changes in sediment connectivity at source-bordering aeolian dunefields in the Grand Canyon, USA. Controlled floods from the Glen Canyon Dam are used to build sandbars along the Colorado River in Grand Canyon which provide the main sediment source for aeolian dunefields. Aeolian dunefields are a primary resource of concern for land managers in the Grand Canyon because they often contain buried archaeological features. To characterize dunefield response to controlled floods, we use a novel, automated approach for the mechanistic segregation of geomorphic change to discern the geomorphic processes responsible for driving topographic change in very high resolution digital elevation models-of-difference (DODs) that span multiple, consecutive controlled river floods at source-bordering dunefields. We subsequently compare the results of mechanistic segregation with modelled estimates of aeolian dunefield evolution in order to understand how dunefields respond to contemporary, anthropogenically-driven variability in sediment supply and connectivity. These methods provide a rapid technique for sediment budgeting and enable the inference of spatial and temporal patterns in sediment flux between the fluvial and aeolian domains. We anticipate that this approach will be adaptable to other river valleys where the interactions of aeolian, fluvial, and hillslope processes drive sediment connectivity for the maintenance of source-bordering aeolian dunefields.

Slope basins, headless canyons, and submarine palaeoseismology of the Cascadia accretionary complex

USGS Publications Warehouse

McAdoo, B.G.; Orange, D.L.; Screaton, Elizabeth; Lee, H.; Kayen, R.

1997-01-01

A combination of geomorphological, seismic reflection and geotechnical data constrains this study of sediment erosion and deposition at the toe of the Cascadia accretionary prism. We conducted a series of ALVIN dives in a region south of Astoria Canyon to examine the interrelationship of fluid flow and slope failure in a series of headless submarine canyons. Elevated head gradients at the inflection point of canyons have been inferred to assist in localized failures that feed sediment into a closed slope basin. Measured head gradients are an order of magnitude too low to cause seepage-induced slope failure alone; we therefore propose transient slope failure mechanisms. Intercanyon slopes are uniformly unscarred and smooth, although consolidation tests indicate that up to several metres of material may have been removed. A sheet-like failure would remove sediment uniformly, preserving the observed smooth intercanyon slope. Earthquake-induced liquefaction is a likely trigger for this type of sheet failure as the slope is too steep and short for sediment flow to organize itself into channels. Bathymetric and seismic reflection data suggest sediment in a trench slope basin between the second and third ridges from the prism's deformation is derived locally. A comparison of the amounts of material removed from the slopes and that in the basin shows that the amount of material removed from the slopes may slightly exceed the amount of material in the basin, implying that a small amount of sediment has escaped the basin, perhaps when the second ridge was too low to form a sufficient dam, or through a gap in the second ridge to the south. Regardless, almost 80% of the material shed off the slopes around the basin is deposited locally, whereas the remaining 20% is redeposited on the incoming section and will be re-accreted.

Submarine sand dunes and sedimentary environments in Oceanographer Canyon.

USGS Publications Warehouse

Valentine, P.C.; Cooper, R.A.; Uzmann, J.R.

1984-01-01

Observations from research submersibles in the northern part of Oceanographer Canyon reveal the presence of an extensive field of large sand dunes on the canyon floor. The dunes are medium to coarse sand, are oriented across the axis, and the largest of them are as high as 3 m and have wavelengths up to 15 m. Their asymmetry, grain size, and height suggest that they are formed by axial currents flowing up- and downcanyon and that the largest dunes require flows of at least 70 cm/sec. Shelf sand, low in silt and clay content, is transported by currents down and along the canyon walls onto the canyon floor. As the sand enters the canyon, it is mixed with immobile gravel deposits on the canyon rim; lower on the walls, the sand is mixed with silt and clay burrowed by organisms from the semiconsolidated sandy silt that underlies the canyon walls and floor. Upon reaching the canyon floor, the sand is sculpted into bed forms by currents, and the fines are winnowed out and transported out of the canyon. At present, the shelf and canyon walls are being eroded by bottom currents and burrowing organisms, whereas the canyon floor is covered by mobile sand that moves both up and down the axis in this part of the canyon.

Coupled dam safety analysis using WinDAM

USDA-ARS?s Scientific Manuscript database

Windows® Dam Analysis Modules (WinDAM) is a set of modular software components that can be used to analyze overtopping and internal erosion of embankment dams. Dakota is an extensive software framework for design exploration and simulation. These tools can be coupled to create a powerful framework...

Tiffany Diamonds and Classical Music as Influences on the Performance of "Don Juan in Hell".

ERIC Educational Resources Information Center

Johnson, Jim

This paper analyzes Paul Gregory's 1951 production of "Don Juan in Hell," now considered to be a seminal work in the development of professional and educational readers theatre. The paper contends that the production, which presented a nondramatic work without the usual emphasis on design and spectacle, forced a reexamination of the role…

36 CFR 292.47 - Mining activities.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Mining activities. 292.47 Section 292.47 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.47 Mining activities. (a) Other...

36 CFR 292.47 - Mining activities.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Mining activities. 292.47 Section 292.47 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.47 Mining activities. (a) Other...

36 CFR 292.47 - Mining activities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Mining activities. 292.47 Section 292.47 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.47 Mining activities. (a) Other...

36 CFR 292.47 - Mining activities.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Mining activities. 292.47 Section 292.47 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.47 Mining activities. (a) Other...

50 CFR Table 3 to Part 226 - Hydrologic Units Containing Critical Habitat for Snake River Sockeye Salmon and Snake River...

Code of Federal Regulations, 2014 CFR

2014-10-01

... Habitat for Snake River Sockeye Salmon and Snake River Spring/Summer and Fall Chinook Salmon 3 Table 3 to... Spring/Summer and Fall Chinook Salmon Hydrologic unit name Hydrologic unit number Sockeye salmon Spring/summer chinook salmon Fall chinook salmon Hells Canyon 17060101 17060101 Imnaha 17060102 17060102 Lower...

50 CFR Table 3 to Part 226 - Hydrologic Units Containing Critical Habitat for Snake River Sockeye Salmon and Snake River...

Code of Federal Regulations, 2013 CFR

2013-10-01

... Habitat for Snake River Sockeye Salmon and Snake River Spring/Summer and Fall Chinook Salmon 3 Table 3 to... Spring/Summer and Fall Chinook Salmon Hydrologic unit name Hydrologic unit number Sockeye salmon Spring/summer chinook salmon Fall chinook salmon Hells Canyon 17060101 17060101 Imnaha 17060102 17060102 Lower...

50 CFR Table 3 to Part 226 - Hydrologic Units Containing Critical Habitat for Snake River Sockeye Salmon and Snake River...

Code of Federal Regulations, 2012 CFR

2012-10-01

... Habitat for Snake River Sockeye Salmon and Snake River Spring/Summer and Fall Chinook Salmon 3 Table 3 to... Spring/Summer and Fall Chinook Salmon Hydrologic unit name Hydrologic unit number Sockeye salmon Spring/summer chinook salmon Fall chinook salmon Hells Canyon 17060101 17060101 Imnaha 17060102 17060102 Lower...

The Morpho-Acoustic Structure of Sakarya Canyon, Southwestern Black Sea

NASA Astrophysics Data System (ADS)

Nasıf, Aslıhan; Dondurur, Derman

2017-04-01

In this study, Black Sea outlet of Sakarya River in the western Black Sea continental margin is analyzed using a total of 1400 km multichannel seismics, Chirp sub-bottom profiler and multibeam bathymetric datasets. Three scientific cruises between 2012 and 2016 have been conducted in the area to map and reveal the morphological structure of the Sakarya Canyon along the southwestern Black Sea margin. The Western Black Sea Turkey coastal area is also home to many active canyons. These canyons extend from deep shallow shelf areas of about 100 m to deep water depths of 1800-2000 m. The largest and most active of the Western Black Sea canyons is the Sakarya Canyon, which is located at the exit of the Sakarya River. Research on submarine canyons are important for military submarine operations, positioning of marine engineering structures and understanding the sedimentology, ecological and oceanographic functions of canyons. The canyon systems observed on continental slopes lead to the most convenient sedimentary transportation from the shelf platform. The dataset from study area was analyzed to identify the acoustic structure of Sakarya Canyon, the morphology of which is not widely known. Bathymetric data shows that the canyon consists of two separate canyon heads in the shallow continental shelf to the south, both of which coalesce at 867 m water depth. This meandering canyon then deepens along the continental slope towards to north. Another wide canyon from west, named as Kefken Canyon, then conjoins this main canyon at approximately 1000 m water depths to form the deeper structure of the modern Sakarya Canyon. In the distal parts, canyon gets wider and wider, and its thalweg becomes significantly flat eroded by the present day activity of small scale turbidity channels. Multichannel seismic data indicate that the Sakarya Canyon was formed by the activity of hyperphycnal flows and also clearly show the extensive sediment erosion along the canyon.

Turbidity, light, temperature, and hydropeaking control primary productivity in the Colorado River, Grand Canyon

USGS Publications Warehouse

Hall, Robert O.; Yackulic, Charles B.; Kennedy, Theodore A.; Yard, Michael D.; Rosi-Marshall, Emma J.; Voichick, Nicholas; Behn, Kathrine E.

2015-01-01

Dams and river regulation greatly alter the downstream environment for gross primary production (GPP) because of changes in water clarity, flow, and temperature regimes. We estimated reach-scale GPP in five locations of the regulated Colorado River in Grand Canyon using an open channel model of dissolved oxygen. Benthic GPP dominates in Grand Canyon due to fast transport times and low pelagic algal biomass. In one location, we used a 738 days time series of GPP to identify the relative contribution of different physical controls of GPP. We developed both linear and semimechanistic time series models that account for unmeasured temporal covariance due to factors such as algal biomass dynamics. GPP varied from 0 g O2 m−2 d−1 to 3.0 g O2 m−2 d−1 with a relatively low annual average of 0.8 g O2 m−2d−1. Semimechanistic models fit the data better than linear models and demonstrated that variation in turbidity primarily controlled GPP. Lower solar insolation during winter and from cloud cover lowered GPP much further. Hydropeaking lowered GPP but only during turbid conditions. Using the best model and parameter values, the model accurately predicted seasonal estimates of GPP at 3 of 4 upriver sites and outperformed the linear model at all sites; discrepancies were likely from higher algal biomass at upstream sites. This modeling approach can predict how changes in physical controls will affect relative rates of GPP throughout the 385 km segment of the Colorado River in Grand Canyon and can be easily applied to other streams and rivers.

Large-scale dam removal on the Elwha River, Washington, USA: source-to-sink sediment budget and synthesis

USGS Publications Warehouse

Warrick, Jonathan A.; Bountry, Jennifer A.; East, Amy E.; Magirl, Christopher S.; Randle, Timothy J.; Gelfenbaum, Guy R.; Ritchie, Andrew C.; Pess, George R.; Leung, Vivian; Duda, Jeff J.

2015-01-01

waters, where slightly less than half of the sediment was deposited in the river-mouth delta. Although most of the measured fluvial and coastal deposition was sand-sized and coarser (> 0.063 mm), significant mud deposition was observed in and around the mainstem river channel and on the seafloor. Woody debris, ranging from millimeter-size particles to old-growth trees and stumps, was also introduced to fluvial and coastal landforms during the dam removals. At the end of our two-year study, Elwha Dam was completely removed, Glines Canyon Dam had been 75% removed (full removal was completed 2014), and ~ 65% of the combined reservoir sediment masses—including ~ 8 Mt of fine-grained and ~ 12 Mt of coarse-grained sediment—remained within the former reservoirs. Reservoir sediment will continue to be released to the Elwha River following our two-year study owing to a ~ 16 m base level drop during the final removal of Glines Canyon Dam and to erosion from floods with larger magnitudes than occurred during our study. Comparisons with a geomorphic synthesis of small dam removals suggest that the rate of sediment erosion as a percent of storage was greater in the Elwha River during the first two years of the project than in the other systems. Comparisons with other Pacific Northwest dam removals suggest that these steep, high-energy rivers have enough stream power to export volumes of sediment deposited over several decades in only months to a few years. These results should assist with predicting and characterizing landscape responses to future dam removals and other perturbations to fluvial and coastal sediment budgets.

Dinosaur Census Reveals Abundant Tyrannosaurus and Rare Ontogenetic Stages in the Upper Cretaceous Hell Creek Formation (Maastrichtian), Montana, USA

PubMed Central

Horner, John R.; Goodwin, Mark B.; Myhrvold, Nathan

2011-01-01

Background A dinosaur census recorded during the Hell Creek Project (1999–2009) incorporates multiple lines of evidence from geography, taphohistory, stratigraphy, phylogeny and ontogeny to investigate the relative abundance of large dinosaurs preserved in the Upper Cretaceous Hell Creek Formation of northeastern Montana, USA. Overall, the dinosaur skeletal assemblages in the Hell Creek Formation (excluding lag-influenced records) consist primarily of subadult or small adult size individuals. Small juveniles and large adults are both extremely rare, whereas subadult individuals are relatively common. We propose that mature individuals of at least some dinosaur taxa either lived in a separate geographic locale analogous to younger individuals inhabiting an upland environment where sedimentation rates were relatively less, or these taxa experienced high mortality before reaching terminal size where late stage and often extreme cranial morphology is expressed. Methodology/Principal Findings Tyrannosaurus skeletons are as abundant as Edmontosaurus, an herbivore, in the upper Hell Creek Formation and nearly twice as common in the lower third of the formation. Smaller, predatory dinosaurs (e.g., Troodon and dromaeosaurids) are primarily represented by teeth found in microvertebrate localities and their skeletons or identifiable lag specimens were conspicuously absent. This relative abundance suggests Tyrannosaurus was not a typical predator and likely benefited from much wider food choice opportunities than exclusively live prey and/or specific taxa. Tyrannosaurus adults may not have competed with Tyrannosaurus juveniles if the potential for selecting carrion increased with size during ontogeny. Conclusions/Significance Triceratops is the most common dinosaur and isolated skulls contribute to a significant portion of this census. Associated specimens of Triceratops consisting of both cranial and postcranial elements remain relatively rare. This rarity may be explained

Ventilation Processes in a Three-Dimensional Street Canyon

NASA Astrophysics Data System (ADS)

Nosek, Štěpán; Kukačka, Libor; Kellnerová, Radka; Jurčáková, Klára; Jaňour, Zbyněk

2016-05-01

The ventilation processes in three different street canyons of variable roof geometry were investigated in a wind tunnel using a ground-level line source. All three street canyons were part of an urban-type array formed by courtyard-type buildings with pitched roofs. A constant roof height was used in the first case, while a variable roof height along the leeward or windward walls was simulated in the two other cases. All street-canyon models were exposed to a neutrally stratified flow with two approaching wind directions, perpendicular and oblique. The complexity of the flow and dispersion within the canyons of variable roof height was demonstrated for both wind directions. The relative pollutant removals and spatially-averaged concentrations within the canyons revealed that the model with constant roof height has higher re-emissions than models with variable roof heights. The nomenclature for the ventilation processes according to quadrant analysis of the pollutant flux was introduced. The venting of polluted air (positive fluctuations of both concentration and velocity) from the canyon increased when the wind direction changed from perpendicular to oblique, irrespective of the studied canyon model. Strong correlations (>0.5) between coherent structures and ventilation processes were found at roof level, irrespective of the canyon model and wind direction. This supports the idea that sweep and ejection events of momentum bring clean air in and detrain the polluted air from the street canyon, respectively.

36 CFR 292.47 - Mining activities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Mining activities. 292.47... RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.47 Mining activities. (a) Other Lands. The standards and guidelines of this section apply to mining activities in the Other Lands...

36 CFR 292.44 - Use of motorized and mechanical equipment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Use of motorized and mechanical equipment. 292.44 Section 292.44 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.44 Use of...

36 CFR 292.44 - Use of motorized and mechanical equipment.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Use of motorized and mechanical equipment. 292.44 Section 292.44 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.44 Use of...

36 CFR 292.44 - Use of motorized and mechanical equipment.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Use of motorized and mechanical equipment. 292.44 Section 292.44 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.44 Use of...

78 FR 73186 - Wallowa-Whitman National Forests, Oregon; Lower Imnaha Rangeland Analysis

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-05

... Creek, Cow Creek, and a portion of the Snake River watersheds of the Hells Canyon National Recreation... associated watersheds downstream of the Imnaha River Bridge ``Cow Creek Bridge'', and watersheds from Deep... allotments: Cow Creek, Lone Pine, Rhodes Creek, and Toomey, all of which are in Wallowa County, Oregon. This...

Flow structures and sandbar dynamics in a canyon river during a controlled flood, Colorado River, Arizona

USGS Publications Warehouse

Wright, S.A.; Kaplinski, M.

2011-01-01

In canyon rivers, debris fan constrictions create rapids and downstream pools characterized by secondary flow structures that are closely linked to channel morphology. In this paper we describe detailed measurements of the three-dimensional flow structure and sandbar dynamics of two pools along the Colorado River in the Grand Canyon during a controlled flood release from Glen Canyon Dam. Results indicate that the pools are characterized by large lateral recirculation zones (eddies) resulting from flow separation downstream from the channel constrictions, as well as helical flow structures in the main channel and eddy. The lateral recirculation zones are low-velocity areas conducive to fine sediment deposition, particularly in the vicinity of the separation and reattachment points and are thus the dominant flow structures controlling sandbar dynamics. The helical flow structures also affect morphology but appear secondary in importance to the lateral eddies. During the controlled flood, sandbars in the separation and reattachment zones at both sites tended to build gradually during the rising limb and peak flow. Deposition in shallow water on the sandbars was accompanied by erosion in deeper water along the sandbar slope at the interface with the main channel. Erosion occurred via rapid mass failures as well as by gradual boundary shear stress driven processes. The flow structures and morphologic links at our study sites are similar to those identified in other river environments, in particular sharply curved meanders and channel confluences where the coexistence of lateral recirculation and helical flows has been documented. Copyright 2011 by the American Geophysical Union.

Geology and biology of Oceanographer submarine canyon.

USGS Publications Warehouse

Valentine, P.C.; Uzmann, J.R.; Cooper, R.A.

1980-01-01

Santonian beds more than 100 m thick are the oldest rocks collected from the canyon. Quaternary silty clay veneers the canyon walls in many places and is commonly burrowed by benthic organisms that cause extensive erosion of the canyon walls, especially in the depth zone (100-1300 m) inhabited by the crabs Geryon and Cancer. Bioerosion is minimal on high, near-vertical cliffs of sedimentary rock, in areas of continual sediment movement, and where the sea floor is paved by gravel. A thin layer of rippled, unconsolidated silt and sand is commonly present on the canyon walls and in the axis. Shelf sediments are transported from Georges Bank over the E rim and in the Canyon by the SW drift and storm currents; tidal currents and internal waves move the sediment downcanyon along the walls and axis.- from Authors

Discovery of two new large submarine canyons in the Bering Sea

USGS Publications Warehouse

Carlson, P.R.; Karl, Herman A.

1984-01-01

The Beringian continental margin is incised by some of the world's largest submarine canyons. Two newly discovered canyons, St. Matthew and Middle, are hereby added to the roster of Bering Sea canyons. Although these canyons are smaller and not cut back into the Bering shelf like the five very large canyons, they are nonetheless comparable in size to most of the canyons that have been cut into the U.S. eastern continental margin and much larger than the well-known southern California canyons. Both igneous and sedimentary rocks of Eocene to Pliocene age have been dredged from the walls of St. Matthew and Middle Canyons as well as from the walls of several of the other Beringian margin canyons, thus suggesting a late Tertiary to Quaternary genesis of the canyons. We speculate that the ancestral Yukon and possibly Anadyr Rivers were instrumental in initiating the canyon-cutting processes, but that, due to restrictions imposed by island and subsea bedrock barriers, cutting of the two newly discovered canyons may have begun later and been slower than for the other five canyons. ?? 1984.

Chapter 12. Canyons microbiology studies

USGS Publications Warehouse

Kellogg, Christina A.; Lawler, Stephanie N.

2017-01-01

Off the eastern coast of the United States, several deep canyons cut through the continental shelf, acting like funnels to move sediment from the shelf out to the deep seafloor. Exposed rock outcrops and ledges along the walls of these canyons provide important habitat for deepsea corals and sponges. Although a few scientific expeditions have visited these canyons in the 1970s (Hecker and Blechschmidt 1979, Hecker et al. 1980), their purpose was mainly to map the contours and capture photographs of the bottom using manned submersibles and towed cameras. Our knowledge of the biodiversity in these complex ecosystems is limited; we know little about the macrofauna (e.g., fishes, crabs, sponges, and deepsea corals) and even less about the microbiota.The research described in this report was conducted from 2011 to 2015 as part of the Bureau of Ocean Energy Management (BOEM) study, entitled “Atlantic Deepwater Canyons” study. This work used molecular and microbiological techniques to examine the microbial ecology and diversity associated with Baltimore and Norfolk canyons. Specifically, this work focused on the microbial ecology of four species of octocorals (Acanthogorgia aspera, Anthothela grandiflora, Paramuricea placomus, and Primnoa resedaeformis), the microbial diversity in sediments within and outside the canyons, and a settling plate experiment designed to characterize microbial biofilm formation on a variety of hard substrates.

36 CFR 7.19 - Canyon de Chelly National Monument.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Canyon de Chelly National... INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.19 Canyon de Chelly National Monument. (a) Visitors are prohibited from entering the canyons of Canyon de Chelly National Monument unless...

36 CFR 7.19 - Canyon de Chelly National Monument.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Canyon de Chelly National... INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.19 Canyon de Chelly National Monument. (a) Visitors are prohibited from entering the canyons of Canyon de Chelly National Monument unless...

Morphodynamic Model of Submarine Canyon Incision by Sandblasting

NASA Astrophysics Data System (ADS)

Zhang, L.; Parker, G.; Izumi, N.; Cartigny, M.; Li, T.; Wang, G.

2017-12-01

Submarine canyons are carved by turbidity currents under the deep sea. As opposed to subaerial canyons, the relevant processes are not easy to observe directly. Turbidity currents are bottom-hugging sediment gravity flows of that can incise or deposit on the seafloor to create submarine canyons or fans. The triggers of turbidity currents can be storms, edge waves, internal waves, canyon wall sapping, delta failure, breaching and hyperpycnal flows. The formation and evolution mechanisms of submarine canyons are similar to those of subaerial canyons, but have substantial differences. For example, sandblasting, rather than wear due to colliding gravel clasts is more likely to be the mechanism of bedrock incision. Submarine canyons incise downward, and often develop meander bends and levees within the canyon, so defining "fairways". Here we propose a simple model for canyon incision. The starting point of our model is the Macro Roughness Saltation Abrasion Alluviation model of Zhang et al. [2015], designed for bedrock incision by gravel clasts in mixed bedrock-alluvial rivers. We adapt this formulation to consider sandblasting as a means of wear. We use a layer-averaged model for turbidity current dynamics. The current contains a mixture of mud, which helps drive the flow but which does not cause incision, and sand, which is the agent of incision. We show that the model can successfully model channel downcutting, and indeed illustrate the early formation of net incisional cyclic steps, i.e. upstream-migrating undulations on the bed associated with transcritical (in the Froude sense) flow. These steps can be expected to abet the process of incision.

36 CFR 292.24 - Determination of compliance and noncompliance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... land is assigned (§ 292.23); (ii) The use of development that exists or that is proposed for the property; (iii) A statement as to whether a change in the land category assignment will be necessary to..., DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Private Lands § 292...

1. GORGE HIGH DAM. THIS THIN ARCH DAM WITH A ...

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

1. GORGE HIGH DAM. THIS THIN ARCH DAM WITH A GRAVITY SECTION IS THE THIRD DAM BUILT BY SEATTLE CITY LIGHT TO PROVIDE WATER FOR GORGE POWERHOUSE AND WAS COMPLETED IN 1961, 1989. - Skagit Power Development, Gorge High Dam, On Skagit River, 2.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

Diets of insectivorous birds along the Colorado River in Grand Canyon, Arizona

USGS Publications Warehouse

Yard, H.K.; van Riper, Charles; Brown, B.T.; Kearsley, M.J.

2004-01-01

We examined diets of six insectivorous bird species (n = 202 individuals) from two vegetation zones along the Colorado River in Grand Canyon National Park, Arizona, 1994. All bird species consumed similar quantities of caterpillars and beetles, but use of other prey taxa varied. Non-native leafhoppers (Opsius stactagolus) specific to non-native tamarisk (Tamarix chinensis) substantially augmented Lucy's Warbler (Vermivora luciae) diets (49%), while ants comprised 82% of Yellow-breasted Chat (Icteria virens) diets. Yellow Warbler (Dendroica petechia) diets were composed of 45% aquatic midges. All bird species consumed the non-native leafhopper specific to tamarisk. Comparison of bird diets with availability of arthropod prey from aquatic and terrestrial origins showed terrestrial insects comprised 91% of all avian diets compared to 9% of prey from aquatic origin. Seasonal shifts in arthropod prey occurred in diets of three bird species, although no seasonal shifts were detected in arthropods sampled in vegetation indicating that at least three bird species were not selecting prey in proportion to its abundance. All bird species had higher prey overlap with arthropods collected in the native, mesquite-acacia vegetation zone which contained higher arthropod diversity and better prey items (i.e., Lepidoptera). Lucy's Warbler and Yellow Warbler consumed high proportions of prey items found in greatest abundance in the tamarisk-dominated vegetation zone that has been established since the construction of Glen Canyon Dam. These species appeared to exhibit ecological plasticity in response to an anthropogenic increase in prey resources.

Extending the turbidity record: making additional use of continuous data from turbidity, acoustic-Doppler, and laser diffraction instruments and suspended-sediment samples in the Colorado River in Grand Canyon

USGS Publications Warehouse

Voichick, Nicholas; Topping, David J.

2014-01-01

range of sediment concentrations in the study area using data from the ADP instruments is particularly useful for biological studies. In Grand Canyon, turbidity has been correlated with food availability for aquatic organisms (gross primary production) as well as with fish behavior specific to predator-prey interactions. On the basis of the complete “extended” turbidity record and the relation between suspended-sediment concentration and turbidity, levels were higher before the construction of Glen Canyon Dam by a factor of approximately 2,000 at the Lees Ferry monitoring station (15 miles downstream from the dam) and by a factor of approximately 20 at the monitoring station 87 miles downstream from Lees Ferry (102 miles downstream from the dam). A comparison of turbidity data with data from Laser In-Situ Scattering and Transmissometry (LISST) laser-diffraction instruments, suspended-sediment concentration data, and ADP data shows the influence of the physical properties of suspended sediment. Apparent outliers in relations between turbidity, ADP, and suspended-sediment data during two events within the study period, a 2007 tributary flood from a watershed altered by a recent wildfire and a 2008 experimental controlled-flood release from Glen Canyon Dam, are explained in part by atypical grain sizes, shapes, densities, colors, and (or) clay mineral assemblages of suspended sediment occurring in the Colorado River during these two events. These analyses demonstrate the value of using multiple data-collection strategies for turbidity and sediment-transport studies and of continuous monitoring for capturing the full range and duration of turbidity and sediment-transport conditions, identifying the provenance of the sediment causing turbidity, and detecting physical and chemical processes that may be important for management of critical physical and biological resources.

Why SRS Matters - H Canyon

ScienceCinema

Hunt, Paul; Lewczyk, Mike; Swain, Mike

2018-06-22

A video series presenting an overview of the Savannah River Site's (SRS) mission and operations. Each episode features a specific area/operation and how it contributes to help make the world safer. This episode features H Canyon's mission and operations. H Canyon and its adjoining H B Line facility represent the last full-scale radio chemical processing capabilities left in the United States.

Deer Creek Dam, Dam, 1,204 feet/238 degrees from intersection of ...

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

Deer Creek Dam, Dam, 1,204 feet/238 degrees from intersection of dam complex access road and U.S. Highway 189 to center of dam, 874 feet/352 degrees from Hydroelectric Powerplant (HAER UT-93-B) to center of dam, Charleston, Wasatch County, UT

Ecosystem ecology meets adaptive management: food web response to a controlled flood on the Colorado River, Glen Canyon

USGS Publications Warehouse

Cross, Wyatt F.; Baxter, Colden V.; Donner, Kevin C.; Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Hall, Robert O.; Wellard Kelly, Holly A.; Rogers, R. Scott

2011-01-01

Large dams have been constructed on rivers to meet human demands for water, electricity, navigation, and recreation. As a consequence, flow and temperature regimes have been altered, strongly affecting river food webs and ecosystem processes. Experimental high-flow dam releases, i.e., controlled floods, have been implemented on the Colorado River, USA, in an effort to reestablish pulsed flood events, redistribute sediments, improve conditions for native fishes, and increase understanding of how dam operations affect physical and biological processes. We quantified secondary production and organic matter flows in the food web below Glen Canyon dam for two years prior and one year after an experimental controlled flood in March 2008. Invertebrate biomass and secondary production declined significantly following the flood (total biomass, 55% decline; total production, 56% decline), with most of the decline driven by reductions in two nonnative invertebrate taxa, Potamopyrgus antipodarum and Gammarus lacustris. Diatoms dominated the trophic basis of invertebrate production before and after the controlled flood, and the largest organic matter flows were from diatoms to the three most productive invertebrate taxa (P. antipodarum, G. lacustris, and Tubificida). In contrast to invertebrates, production of rainbow trout (Oncorhynchus mykiss) increased substantially (194%) following the flood, despite the large decline in total secondary production of the invertebrate assemblage. This counterintuitive result is reconciled by a post-flood increase in production and drift concentrations of select invertebrate prey (i.e., Chironomidae and Simuliidae) that supported a large proportion of trout production but had relatively low secondary production. In addition, interaction strengths, measured as species impact values, were strongest between rainbow trout and these two taxa before and after the flood, demonstrating that the dominant consumer—resource interactions were not

McNary Dam, Ice Harbor Dam, and Lower Monumental Dam Smolt Monitoring Program; 1996 Annual Report.

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

Hillson, Todd; Lind, Sharon; Price, William

1997-07-01

The Washington Department of Fish & Wildlife (WDFW) assumed responsibility for the Smolt Monitoring Program at McNary Dam on the Columbia River in 1990 and at the new juvenile collection facility at Lower Monumental Dam on the Snake River in 1993. In 1996, Smolt Monitoring Program activities also began at the new juvenile collection facility located at Ice Harbor Dam. This report summarizes the 1996 Smolt Monitoring work at all three sites. The work at Ice Harbor consisted of Gas Bubble Trauma (GBT) monitoring only. In general, the 1996 passage season at both the McNary and Lower Monumental sites canmore » be characterized by reduced passage of juveniles through the collection systems due to elevated river flows and spill, and low (<1%) overall facility mortality rates most likely resulting from cooler water temperatures. In accordance with the National Marine Fisheries Service recommendations (NMFS, 1995) all spring migrants were bypassed at McNary Dam in 1996. Mechanical problems within the McNary collection system resulted in collection and sampling activities being delayed until April 18 at this site, while sampling and collection began on the scheduled starting date of April 1 at Lower Monumental Dam. Monitoring operations were conducted through December 14 at McNary Dam and through October 28 at Lower Monumental Dam. An ongoing transportation evaluation summer migrant marking program was conducted at McNary Dam in 1996 by the NMFS. This necessitated the sampling of 394,211 additional fish beyond the recommended sampling guidelines. All total, 509,237 and 31,219 juvenile salmonids were anesthetized and individually counted, examined for scale loss, injuries, and brands by WDFW Smolt Monitoring personnel in 1996 at McNary Dam and Lower Monumental Dam, respectively.« less

Large-scale dam removal on the Elwha River, Washington, USA: coastal geomorphic change

USGS Publications Warehouse

Gelfenbaum, Guy R.; Stevens, Andrew W.; Miller, Ian M.; Warrick, Jonathan A.; Ogston, Andrea S.; Eidam, Emily

2015-01-01

Two dams on the Elwha River, Washington State, USA trapped over 20 million m3 of mud, sand, and gravel since 1927, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams, initiated in September 2011, induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the geomorphic response of a coastal delta to these increases. Detailed measurements of beach topography and nearshore bathymetry show that ~ 2.5 million m3 of sediment was deposited during the first two years of dam removal, which is ~ 100 times greater than deposition rates measured prior to dam removal. The majority of the deposit was located in the intertidal and shallow subtidal region immediately offshore of the river mouth and was composed of sand and gravel. Additional areas of deposition include a secondary sandy deposit to the east of the river mouth and a muddy deposit west of the mouth. A comparison with fluvial sediment fluxes suggests that ~ 70% of the sand and gravel and ~ 6% of the mud supplied by the river was found in the survey area (within about 2 km of the mouth). A hydrodynamic and sediment transport model, validated with in-situ measurements, shows that tidal currents interacting with the larger relict submarine delta help disperse fine sediment large distances east and west of the river mouth. The model also suggests that waves and currents erode the primary deposit located near the river mouth and transport sandy sediment eastward to form the secondary deposit. Though most of the substrate of the larger relict submarine delta was unchanged during the first two years of dam removal, portions of the seafloor close to the river mouth became finer, modifying habitats for biological communities. These results show that river restoration, like natural changes in river sediment supply, can result in rapid and substantial coastal geomorphological

40 CFR 81.425 - Oregon.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Oregon. 81.425 Section 81.425... Visibility Is an Important Value § 81.425 Oregon. Area name Acreage Public Law establishing Federal land... Hells Canyon Wilderness, 192,700 acres overall, of which 108,900 acres are in Oregon, and 83,800 acres...

40 CFR 81.425 - Oregon.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Oregon. 81.425 Section 81.425... Visibility Is an Important Value § 81.425 Oregon. Area name Acreage Public Law establishing Federal land... Hells Canyon Wilderness, 192,700 acres overall, of which 108,900 acres are in Oregon, and 83,800 acres...

40 CFR 81.425 - Oregon.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Oregon. 81.425 Section 81.425... Visibility Is an Important Value § 81.425 Oregon. Area name Acreage Public Law establishing Federal land... Hells Canyon Wilderness, 192,700 acres overall, of which 108,900 acres are in Oregon, and 83,800 acres...

40 CFR 81.425 - Oregon.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Oregon. 81.425 Section 81.425... Visibility Is an Important Value § 81.425 Oregon. Area name Acreage Public Law establishing Federal land... Hells Canyon Wilderness, 192,700 acres overall, of which 108,900 acres are in Oregon, and 83,800 acres...

40 CFR 81.425 - Oregon.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Oregon. 81.425 Section 81.425... Visibility Is an Important Value § 81.425 Oregon. Area name Acreage Public Law establishing Federal land... Hells Canyon Wilderness, 192,700 acres overall, of which 108,900 acres are in Oregon, and 83,800 acres...

Pollutant Dilution and Diffusion in Urban Street Canyon Neighboring Streets

NASA Astrophysics Data System (ADS)

Sun, Z.; Fu, Zh. M.

2011-09-01

In the present study we investigated the airflow patterns and air quality of a series of typical street canyon combinations, developed a mass balance model to determine the local pollutant dilution rate, and discuss the impact of upstream canyon on the air quality of downstream canyon. The results indicated that the geometrical size of upstream and downstream buildings have significant impacts on the ambient airflow patterns. The pollution distribution within the canyons varies with different building combinations and flow patterns. Within the upstream canyon, pollution always accumulates to the low building side for non-symmetrical canyon, and for symmetrical canyon high level of pollution occurs at the leeward side. The height of the middle and downstream buildings can evidently change the pollutant dispersion direction during the transport process. Within the polluted canyon, the pollutant dilution rate (PDR) also varies with different street canyon combinations. The highest PDR is observed when the upstream buildings are both low buildings no matter the height of downstream building. However, the two cases are likely to contribution pollution to the downstream canyon. The H-L-H combination is mostly against local pollution remove, while the L-H-L case is considered the best optimistic building combination with both the ability of diluting local pollution and not remarkably decreasing air quality of downstream canyon. The current work is expected instructive for city designers to optimize traffic patterns under typical existing geometry or in the development of urban geometry modification for air quality control.

Anatomy of La Jolla submarine canyon system; offshore southern California

USGS Publications Warehouse

Paull, C.K.; Caress, D.W.; Lundsten, E.; Gwiazda, R.; Anderson, K.; McGann, M.; Conrad, J.; Edwards, B.; Sumner, E.J.

2013-01-01

An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall geometry of the La Jolla Canyon especially with respect to the pre-canyon host sediments. The floor of the axial channel is covered with unconsolidated sand similar to the sand on the shelf near the canyon head, lacks outcrops of the pre-canyon host strata, has an almost constant slope of 1.0° and is covered with trains of crescent shaped bedforms. The presence of modern plant material entombed within these sands confirms that the axial channel is presently active. The sand on the canyon floor liquefied during vibracore collection and flowed downslope, illustrating that the sediment filling the channel can easily fail even on this gentle slope. Data from the canyon walls help constrain the age of the canyon and extent of incision. Horizontal beds of moderately cohesive fine-grained sediments exposed on the steep canyon walls are consistently less than 1.232 million years old. The lateral continuity of seismic reflectors in minisparker profiles indicate that pre-canyon host strata extend uninterrupted from outside the canyon underneath some terraces within the canyon. Evidence of abandoned channels and point bar-like deposits are noticeably absent on the inside bend of channel meanders and in the subsurface of the terraces. While vibracores from the surface of terraces contain thin (< 10 cm) turbidites, they are inferred to be part of a veneer of recent sediment covering pre-canyon host sediments that underpin the terraces. The combined use of state of the art seafloor mapping and exploration tools provides a uniquely detailed view of the morphology within an active submarine canyon.

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

Bottom-trawling along submarine canyons impacts deep sedimentary regimes.

PubMed

Paradis, Sarah; Puig, Pere; Masqué, Pere; Juan-Díaz, Xènia; Martín, Jacobo; Palanques, Albert

2017-02-24

Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of canyons' morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20 th century, these sedimentary alterations may occur in many trawled canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities.

Hot Canyon

ScienceCinema

None

2018-05-07

This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon".

76 FR 39435 - Notice of Intent To Prepare a Draft Environmental Impact Statement and Conduct Public Scoping on...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-06

... Experimental and Management Plan for the Operation of Glen Canyon Dam AGENCY: Bureau of Reclamation and... Interior (Secretary) Ken Salazar announced that the development of a Long-Term Experimental and Management... GCDAMP includes a Federal advisory committee known as the Glen Canyon Dam Adaptive Management Work Group...

Geology of the Canyon Reservoir site on the Guadalupe River, Comal County, Texas

USGS Publications Warehouse

George, William O.; Welder, Frank A.

1955-01-01

In response to a request by Colonel Harry O. Fisher, District Engineer of the Fort Worth District of the Corps of Engineers, United States Army (letter of Dec. 13, 1954), a reconnaissance investigation was made of the geology of the Canyon (F-1) reservoir site on the Guadalupe River in Comal County, Tex. The purpose of the investigation was to study the geology in relation to possible leakage - particularly leakage of water that might then be lost from the drainage area of the Guadalupe River - and to add to the general knowledge of the ground-water hydrology of the San Antonio area. The dam (F-1) was originally designed for flood control and conservation only, with provision for the addition of a power unit if feasible. Since the completion of the investigation by the Corps of Engineers, the city of San Antonio has expressed an interest in the reservoir as a possible source of public water supply. The Corps of Engineers has made a thorough engineering and geologic study of the dam site (Corps of Engineers, 1950), which has Congressional approval. The geology and water resources of Comal County have been studied by George (1952). The rocks studied are those within the reservoir area and generally below the 1,000-foot contour as shown on the Smithson Valley quadrangle of the U.S. Geological Survey.

Recreational impacts on Colorado River beaches in Glen Canyon, Arizona

NASA Astrophysics Data System (ADS)

Carothers, Steven W.; Johnson, Robert A.; Dolan, Robert

1984-07-01

Recreational impact was measured on eight beaches in Glen Canyon National Recreation Area and 15 beaches in Grand Canyon National Park using permanently located transects and plots. Recreational impact indices included densities of human trash and charcoal and a measure of sand discoloration due to charcoal. Significant increases in the indices occurred on several Glen Canyon beaches over a seven-month period. Sand discoloration became significantly higher over all Glen Canyon beaches during the same time period. All indices were significantly higher in Glen Canyon than on similar Grand Canyon beaches. These differences are probably due to differences in: (a) level of impacts tolerated by the respective management regimes and, (b) in the number of user days among the two National Park Service administrative units. Management alternatives are presented for reversing the present trends of recreational impact on Glen Canyon beaches.

Wind-Flow Patterns in the Grand Canyon as Revealed by Doppler Lidar.

NASA Astrophysics Data System (ADS)

Banta, Robert M.; Darby, Lisa S.; Kaufmann, Pirmin; Levinson, David H.; Zhu, Cui-Juan

1999-08-01

Many interesting flow patterns were found in the Grand Canyon by a scanning Doppler lidar deployed to the south rim during the 1990 Wintertime Visibility Study. Three are analyzed in this study: 1) flow reversal in the canyon, where the flow in the canyon was in the opposite direction from the flow above the canyon rim; 2) under strong, gusty flow from the southwest, the flow inside and above the canyon was from a similar direction and coupled; and 3) under light large-scale ambient flow, the lidar found evidence of local, thermally forced up- and down-canyon winds in the bottom of the canyon.On the days with flow reversal in the canyon, the strongest in-canyon flow response was found for days with northwesterly flow and a strong inversion at the canyon rim. The aerosol backscatter profiles were well mixed within the canyon but poorly mixed across the rim because of the inversion. The gusty southwest flow days showed strong evidence of vertical mixing across the rim both in the momentum and in the aerosol backscatter profiles, as one would expect in turbulent flow. The days with light ambient flow showed poor vertical mixing even inside the canyon, where the jet of down-canyon flow in the bottom of the canyon at night was often either cleaner or dirtier than the air in the upper portions of the canyon. In a case study presented, the light ambient flow regime ended with an intrusion of polluted, gusty, southwesterly flow. The polluted, high-backscatter air took several hours to mix into the upper parts of the canyon. An example is also given of high-backscatter air in the upper portions of the canyon being mixed rapidly down into a jet of cleaner air in the bottom of the canyon in just a few minutes.

ECHETA DAM SPILLWAY. COMING OUT BELOW THE DAM. AT CENTER ...

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

ECHETA DAM SPILLWAY. COMING OUT BELOW THE DAM. AT CENTER OF PHOTO. VIEW TO NORTHEAST. - Echeta Dam & Reservoir, 2.9 miles east of Echeta Road at Echeta Railroad Siding at County Road 293, Echeta, Campbell County, WY

ECHETA DAM RIPRAP ON RESERVOIR SIDE OF THE DAM AT ...

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

ECHETA DAM RIP-RAP ON RESERVOIR SIDE OF THE DAM AT BREACH. VIEW TO NORTH-NORTHEAST. - Echeta Dam & Reservoir, 2.9 miles east of Echeta Road at Echeta Railroad Siding at County Road 293, Echeta, Campbell County, WY

A detached eddy simulation model for the study of lateral separation zones along a large canyon-bound river

NASA Astrophysics Data System (ADS)

Alvarez, Laura V.; Schmeeckle, Mark W.; Grams, Paul E.

2017-01-01

Lateral flow separation occurs in rivers where banks exhibit strong curvature. In canyon-bound rivers, lateral recirculation zones are the principal storage of fine-sediment deposits. A parallelized, three-dimensional, turbulence-resolving model was developed to study the flow structures along lateral separation zones located in two pools along the Colorado River in Marble Canyon. The model employs the detached eddy simulation (DES) technique, which resolves turbulence structures larger than the grid spacing in the interior of the flow. The DES-3D model is validated using Acoustic Doppler Current Profiler flow measurements taken during the 2008 controlled flood release from Glen Canyon Dam. A point-to-point validation using a number of skill metrics, often employed in hydrological research, is proposed here for fluvial modeling. The validation results show predictive capabilities of the DES model. The model reproduces the pattern and magnitude of the velocity in the lateral recirculation zone, including the size and position of the primary and secondary eddy cells, and return current. The lateral recirculation zone is open, having continuous import of fluid upstream of the point of reattachment and export by the recirculation return current downstream of the point of separation. Differences in magnitude and direction of near-bed and near-surface velocity vectors are found, resulting in an inward vertical spiral. Interaction between the recirculation return current and the main flow is dynamic, with large temporal changes in flow direction and magnitude. Turbulence structures with a predominately vertical axis of vorticity are observed in the shear layer becoming three-dimensional without preferred orientation downstream.

A detached eddy simulation model for the study of lateral separation zones along a large canyon-bound river

USGS Publications Warehouse

Alvarez, Laura V.; Schmeeckle, Mark W.; Grams, Paul E.

2017-01-01

Lateral flow separation occurs in rivers where banks exhibit strong curvature. In canyon-boundrivers, lateral recirculation zones are the principal storage of fine-sediment deposits. A parallelized,three-dimensional, turbulence-resolving model was developed to study the flow structures along lateralseparation zones located in two pools along the Colorado River in Marble Canyon. The model employs thedetached eddy simulation (DES) technique, which resolves turbulence structures larger than the grid spacingin the interior of the flow. The DES-3D model is validated using Acoustic Doppler Current Profiler flowmeasurements taken during the 2008 controlled flood release from Glen Canyon Dam. A point-to-pointvalidation using a number of skill metrics, often employed in hydrological research, is proposed here forfluvial modeling. The validation results show predictive capabilities of the DES model. The model reproducesthe pattern and magnitude of the velocity in the lateral recirculation zone, including the size and position ofthe primary and secondary eddy cells, and return current. The lateral recirculation zone is open, havingcontinuous import of fluid upstream of the point of reattachment and export by the recirculation returncurrent downstream of the point of separation. Differences in magnitude and direction of near-bed andnear-surface velocity vectors are found, resulting in an inward vertical spiral. Interaction between therecirculation return current and the main flow is dynamic, with large temporal changes in flow direction andmagnitude. Turbulence structures with a predominately vertical axis of vorticity are observed in the shearlayer becoming three-dimensional without preferred orientation downstream.

The Dams and Monitoring Systems and Case Study: Ataturk and Karakaya Dams

NASA Astrophysics Data System (ADS)

Kalkan, Y.; Bilgi, S.; Gülnerman, A. G.

2017-12-01

Dams are among the most important engineering structures used for flood controls, agricultural purposes as well as drinking and hydroelectric power. Especially after the Second World War, developments on the construction technology, increase the construction of larger capacity dams. There are more than 150.000 dams in the world and almost 1000 dams in Turkey, according to international criteria. Although dams provide benefits to humans, they possess structural risks too. To determine the performance of dams on structural safety, assessing the spatial data is very important. These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. These physical data are measured and monitored by the instruments and equipment. Dams and their surroundings have to be monitored by using essential methods at periodic time intervals in order to determine the possible changes that may occur over the time. Monitoring programs typically consist of; surveillance or visual observation. These programs on dams provide information for evaluating the dam's performance related to the design intent and expected changes that could affect the safety performance of the dam. Additionally, these programs are used for investigating and evaluating the abnormal or degrading performance where any remedial action is necessary. Geodetic and non-geodetic methods are used for monitoring. Monitoring the performance of the dams is critical for producing and maintaining the safe dams. This study provides some general information on dams and their different monitoring systems by taking into account two different dams and their structural specifications with the required information. The case study in this paper depends on a comparison of the monitoring surveys on Atatürk Dam and Karakaya Dam, which are constructed on Firat River with two different structural

Restoring Anadromous Fish Habitat in Big Canyon Creek Watershed, 2004-2005 Annual Report.

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

Rasmussen, Lynn

2006-07-01

The ''Restoring Anadromous Fish Habitat in the Big Canyon Creek Watershed'' is a multi-phase project to enhance steelhead trout in the Big Canyon Creek watershed by improving salmonid spawning and rearing habitat. Habitat is limited by extreme high runoff events, low summer flows, high water temperatures, poor instream cover, spawning gravel siltation, and sediment, nutrient and bacteria loading. Funded by the Bonneville Power Administration (BPA) as part of the Northwest Power Planning Council's Fish and Wildlife Program, the project assists in mitigating damage to steelhead runs caused by the Columbia River hydroelectric dams. The project is sponsored by the Nezmore » Perce Soil and Water Conservation District. Target fish species include steelhead trout (Oncorhynchus mykiss). Steelhead trout within the Snake River Basin were listed in 1997 as threatened under the Endangered Species Act. Accomplishments for the contract period September 1, 2004 through October 31, 2005 include; 2.7 riparian miles treated, 3.0 wetland acres treated, 5,263.3 upland acres treated, 106.5 riparian acres treated, 76,285 general public reached, 3,000 students reached, 40 teachers reached, 18 maintenance plans completed, temperature data collected at 6 sites, 8 landowner applications received and processed, 14 land inventories completed, 58 habitat improvement project designs completed, 5 newsletters published, 6 habitat plans completed, 34 projects installed, 2 educational workshops, 6 displays, 1 television segment, 2 public service announcements, a noxious weed GIS coverage, and completion of NEPA, ESA, and cultural resources requirements.« less

9. Excavation work at Pleasant Dam (now called Waddell Dam). ...

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

9. Excavation work at Pleasant Dam (now called Waddell Dam). Photographer unknown, July, 22, 1926. Source: Maricopa County Municipal Water Conservation District Number One (MWD). - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

32. AERIAL VIEW OF TIETON DAM, UPSTREAM FACE OF DAM ...

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

32. AERIAL VIEW OF TIETON DAM, UPSTREAM FACE OF DAM (Trashrack-structure for outlet at lower left in reservoir, spillway at upper left. Reservoir nearly empty due to drought.) - Tieton Dam, South & East of State Highway 12, Naches, Yakima County, WA

The Wide Bay Canyon system: A case study of canyon morphology on the east Australian continental margin

NASA Astrophysics Data System (ADS)

Yu, P. W.; Hubble, T.; Airey, D.; Gallagher, S. J.; Clarke, S. L.

2014-12-01

A voyage was conducted aboard the RV Southern Surveyor in early 2013 to investigate the east Australian continental margin. From the continental slope of the Wide Bay region offshore Fraser Island, Queensland, Australia, remote sensing data and sediment samples were collected. Bathymetric data reveals that the continental slope of the region presents a mature canyon system. Eight dredge samples were recovered from the walls of Wide Bay Canyon and the adjacent, relatively intact continental slope along the entire length of the slope, from the start of the shelf break to the toe, in water depths ranging from 1100-2500 m. For these samples, sediment composition, biostratigraphic age, and bulk mineralogy data are reported. These slope-forming sediments are primarily comprised of calcareous sandy-silts. Occasional terrestrial plant fossils and minerals can be found in a mostly marine-fossiliferous composition, suggesting minor but significant riverine and aeolian input. Biostratigraphic dates extracted from the foraminiferal contents of these samples indicate that the intra-canyon and slope material was deposited between Middle Miocene to Pliocene, implying that the incision of this section of the margin and formation of the erosional features took place no earlier than the Pliocene. In conjunction with bathymetric data of the local continental slope, the depositional origins of this section of the east Australian continental margin, and the timing of major morphological events such as slope failure and canyon incision can be interpreted. The Wide Bay Canyon system can serve as a representative case study of local canyon formation, allowing a better understanding of the past or ongoing processes that are shaping the margin and giving way to similar morphologies.

36 CFR 292.40 - Purpose and scope.

Code of Federal Regulations, 2013 CFR

2013-07-01

... amended (89 Stat. 1117, 16 U.S.C. 460gg et seq.). (b) Scope. Management of National Forest System lands... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Purpose and scope. 292.40... RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.40 Purpose and scope. (a) Purpose...

36 CFR 292.40 - Purpose and scope.

Code of Federal Regulations, 2012 CFR

2012-07-01

... amended (89 Stat. 1117, 16 U.S.C. 460gg et seq.). (b) Scope. Management of National Forest System lands... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Purpose and scope. 292.40... RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.40 Purpose and scope. (a) Purpose...

36 CFR 292.40 - Purpose and scope.

Code of Federal Regulations, 2011 CFR

2011-07-01

... amended (89 Stat. 1117, 16 U.S.C. 460gg et seq.). (b) Scope. Management of National Forest System lands... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Purpose and scope. 292.40... RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.40 Purpose and scope. (a) Purpose...

36 CFR 292.40 - Purpose and scope.

Code of Federal Regulations, 2010 CFR

2010-07-01

... amended (89 Stat. 1117, 16 U.S.C. 460gg et seq.). (b) Scope. Management of National Forest System lands... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Purpose and scope. 292.40... RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.40 Purpose and scope. (a) Purpose...

36 CFR 292.40 - Purpose and scope.

Code of Federal Regulations, 2014 CFR

2014-07-01

... amended (89 Stat. 1117, 16 U.S.C. 460gg et seq.). (b) Scope. Management of National Forest System lands... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Purpose and scope. 292.40... RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.40 Purpose and scope. (a) Purpose...

Favorable fragmentation: river reservoirs can impede downstream expansion of riparian weeds.

PubMed

Rood, Stewart B; Braatne, Jeffrey H; Goater, Lori A

2010-09-01

River valleys represent biologically rich corridors characterized by natural disturbances that create moist and barren sites suitable for colonization by native riparian plants, and also by weeds. Dams and reservoirs interrupt the longitudinal corridors and we hypothesized that this could restrict downstream weed expansion. To consider this "reservoir impediment" hypothesis we assessed the occurrences and abundances of weeds along a 315-km river valley corridor that commenced with an unimpounded reach of the Snake River and extended through Brownlee, Oxbow, and Hells Canyon reservoirs and dams, and downstream along the Snake River. Sampling along 206 belt transects with 3610 quadrats revealed 16 noxious and four invasive weed species. Ten weeds were upland plants, with Canada thistle (Cirsium arvense) restricted to the upstream reaches, where field morning glory (Convolvulus arvensis) was also more common. In contrast, St. John's wort (Hypericum perforatum) was more abundant below the dams, and medusahead wildrye (Taeniatherum caput-medusae) occurred primarily along the reservoirs. All seven riparian species were abundant in the upstream zones but sparse or absent below the dams. This pattern was observed for the facultative riparian species, poison hemlock (Conium maculatum) and perennial pepperweed (Lepidium latifolium), the obligate riparian, yellow nut sedge (Cyperus esculentus), the invasive perennial, reed canary grass (Phalaris arundinacea), and three invasive riparian trees, Russian olive (Elaeagnus angustifolia), false indigo (Amorpha fruticosa), and tamarisk (Tamarix spp.). The hydrophyte purple loosestrife (Lythrum salicaria) was also restricted to the upstream zone. These longitudinal patterns indicate that the reservoirs have impeded the downstream expansion of riparian weeds, and this may especially result from the repetitive draw-down and refilling of Brownlee Reservoir that imposes a lethal combination of drought and flood stress. The dams and

76 FR 64104 - Notice To Solicit Comments and Hold Public Scoping Meetings on the Adoption of a Long-term...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-17

... Long-term Experimental and Management Plan (LTEMP) for the operation of Glen Canyon Dam. This Federal... and Hold Public Scoping Meetings on the Adoption of a Long-term Experimental and Management Plan for the Operation of Glen Canyon Dam AGENCY: Bureau of Reclamation and National Park Service, Interior...

Factors controlling the abundance of rainbow trout in the Colorado River in Grand Canyon in a reach utilized by endangered humpback chub

USGS Publications Warehouse

Korman, Josh; Yard, Michael D.; Yackulic, Charles B.

2015-01-01

We estimated the abundance, survival, movement, and recruitment of non-native rainbow trout in the Colorado River in Grand Canyon to determine what controls their abundance near the Little Colorado River (LCR) confluence where endangered humpback chub rear. Over a 3-year period, we tagged more than 70,000 trout and recovered over 8,200 tagged fish. Trout density was highest (10,000-25,000 fish/km) in the reach closest to Glen Canyon Dam where the majority of trout recruitment occurs, and was 30-50-fold lower (200-800 fish/km) in reaches near the LCR confluence ~100 km downstream. The extent of rainbow trout movement was limited with less than 1% of recaptures making movements greater than 20 km. However, due to high trout densities in upstream source areas, this small dispersal rate was sufficient to explain the 3-fold increase in the relatively small population near the LCR. Reducing dispersal rates of trout from upstream sources is the most feasible solution to maintain low densities near the LCR to minimize negative effects of competition and predation on humpback chub.

Effects of canyon geometry on the distribution of traffic-related air pollution in a large urban area: Implications of a multi-canyon air pollution dispersion model

NASA Astrophysics Data System (ADS)

Fu, Xiangwen; Liu, Junfeng; Ban-Weiss, George A.; Zhang, Jiachen; Huang, Xin; Ouyang, Bin; Popoola, Olalekan; Tao, Shu

2017-09-01

Street canyons are ubiquitous in urban areas. Traffic-related air pollutants in street canyons can adversely affect human health. In this study, an urban-scale traffic pollution dispersion model is developed considering street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. In the model, vehicle exhausts generated from traffic flows first disperse inside street canyons along the micro-scale wind field generated by computational fluid dynamics (CFD) model. Then, pollutants leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing. We found that an increase in building height leads to heavier pollution inside canyons and lower pollution outside canyons at pedestrian level, resulting in higher domain-averaged concentrations over the area. In addition, canyons with highly even or highly uneven building heights on each side of the street tend to lower the urban-scale air pollution concentrations at pedestrian level. Further, increasing street widths tends to lead to lower pollutant concentrations by reducing emissions and enhancing ventilation simultaneously. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry while considering traffic demand as well as local weather patterns may significantly reduce inhalation of unhealthy air by urban residents.

Characteristics of flow and reactive pollutant dispersion in urban street canyons

NASA Astrophysics Data System (ADS)

Park, Soo-Jin; Kim, Jae-Jin; Kim, Minjoong J.; Park, Rokjin J.; Cheong, Hyeong-Bin

2015-05-01

In this study, the effects of aspect ratio defined as the ratio of building height to street width on the dispersion of reactive pollutants in street canyons were investigated using a coupled CFD-chemistry model. Flow characteristics for different aspect ratios were analyzed first. For each aspect ratio, six emission scenarios with different VOC-NOX ratios were considered. One vortex was generated when the aspect ratio was less than 1.6 (shallow street canyon). When the aspect ratio was greater than 1.6 (deep street canyon), two vortices were formed in the street canyons. Comparing to previous studies on two-dimensional street canyons, the vortex center is slanted toward the upwind building and reverse and downward flows are dominant in street canyons. Near the street bottom, there is a marked difference in flow pattern between in shallow and deep street canyons. Near the street bottom, reverse and downward flows are dominant in shallow street canyon and flow convergence exists near the center of the deep street canyons, which induces a large difference in the NOX and O3 dispersion patterns in the street canyons. NOX concentrations are high near the street bottom and decreases with height. The O3 concentrations are low at high NO concentrations near the street bottom because of NO titration. At a low VOC-NOX ratio, the NO concentrations are sufficiently high to destroy large amount of O3 by titration, resulting in an O3 concentration in the street canyon much lower than the background concentration. At high VOC-NOX ratios, a small amount of O3 is destroyed by NO titration in the lower layer of the street canyons. However, in the upper layer, O3 is formed through the photolysis of NO2 by VOC degradation reactions. As the aspect ratio increases, NOX (O3) concentrations averaged over the street canyons decrease (increase) in the shallow street canyons. This is because outward flow becomes strong and NOX flux toward the outsides of the street canyons increases

7. DARK CANYON SIPHON Photographic copy of construction drawing ...

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

7. DARK CANYON SIPHON - Photographic copy of construction drawing c1907 (from Record Group 115, Box 17, Denver Branch of the National Archives, Denver) DARK CANYON SIPHON PLAN, ELEVATION, AND SECTIONS - Carlsbad Irrigation District, Dark Canyon Siphon, On Main Canal, 1 mile South of Carlsbad, Carlsbad, Eddy County, NM

Slope instabilities along the Western Andean Escarpment and the main canyons in Northern Chile

NASA Astrophysics Data System (ADS)

Crosta, G.; Hermanns, R. L.; Valbuzzi, E.; Dehls, J.; Yugsi Molina, F. X.; Sepulveda, S.

2012-04-01

landslides can be classified as large block slides and can evolve in large rock avalanches. Their initiation seems to be strongly associated to the presence of secondary faults and large fractures transversal to the slope. Furthermore, most of these landslides show evidences suggesting a re-incision by the main canyon network. Landslides along the canyon flanks affect volumes lower than 1 km3 and can be mainly classified as large complex slumps. The deposits of these landslides often cross the valley and have been incised exposing undeformed bedrock material. At the same time large boulder fields and alluvial deposits infill the lower part of the canyons suggesting also a long history of dam breaching events. We present a landslide inventory in the area (about 220 km long and 80 km wide) between Pisagua (19.4° Chile) and Tacna (17.5° Perù) to the NE of the Arica bend. We mapped landslides, main tectonic structures and other morphological features. Mapping has been performed by use of satellite images, Google Earth® and field surveys performed in the last few years. We discuss two specific landslide sites, the Cerro Caquilluco-Cerrillos Negros rock slide-avalanche (Tacna, Tomasiri, Perù) and a small group of rock avalanches south of Iquique (Chile) in two other abstracts presented by the authors at this conference

Impacts of the Columbia River hydroelectric system on main-stem habitats of fall chinook salmon

USGS Publications Warehouse

Dauble, D.D.; Hanrahan, T.P.; Geist, D.R.; Parsley, M.J.

2003-01-01

Salmonid habitats in main-stem reaches of the Columbia and Snake rivers have changed dramatically during the past 60 years because of hydroelectric development and operation. Only about 13% and 58% of riverine habitats in the Columbia and Snake rivers, respectively, remain. Most riverine habitat is found in the upper Snake River; however, it is upstream of Hells Canyon Dam and not accessible to anadromous salmonids. We determined that approximately 661 and 805 km of the Columbia and Snake rivers, respectively, were once used by fall chinook salmon Oncorhynchus tshawytscha for spawning. Fall chinook salmon currently use only about 85 km of the main-stem Columbia River and 163 km of the main-stem Snake River for spawning. We used a geomorphic model to identify three river reaches downstream of present migration barriers with high potential for restoration of riverine processes: the Columbia River upstream of John Day Dam, the Columbia-Snake-Yakima River confluence, and the lower Snake River upstream of Little Goose Dam. Our analysis substantiated the assertion that historic spawning areas for fall chinook salmon occurred primarily within wide alluvial floodplains, which were once common in the mainstem Columbia and Snake rivers. These areas possessed more unconsolidated sediment and more bars and islands and had lower water surface slopes than did less extensively used areas. Because flows in the main stem are now highly regulated, the predevelopment alluvial river ecosystem is not expected to be restored simply by operational modification of one or more dams. Establishing more normative flow regimes - specifically, sustained peak flows for scouring - is essential to restoring the functional characteristics of existing, altered habitats. Restoring production of fall chinook salmon to any of these reaches also requires that population genetics and viability of potential seed populations (i.e., from tributaries, tailrace spawning areas, and hatcheries) be considered.

76 FR 82320 - Extension of Public Scoping Period for the Draft Environmental Impact Statement for Adoption of a...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-30

... Management Plan for the Operation of Glen Canyon Dam AGENCY: Bureau of Reclamation and National Park Service... Impact Statement (EIS) for Adoption of a Long-term Experimental and Management Plan (LTEMP) for the Operation of Glen Canyon Dam to January 31, 2012. The Notice to Solicit Comments and Hold Public Scoping...

5. DARK CANYON SIPHON Photographic copy of historic photo, ...

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

5. DARK CANYON SIPHON - Photographic copy of historic photo, November 11, 1906 (original print located at the Carlsbad Irrigation District offices, Carlsbad, New Mexico) photographer unknown 'LOWER END OF DARK CANYON SIPHON CONSTRUCTION' - Carlsbad Irrigation District, Dark Canyon Siphon, On Main Canal, 1 mile South of Carlsbad, Carlsbad, Eddy County, NM

Bottom-trawling along submarine canyons impacts deep sedimentary regimes

PubMed Central

Paradis, Sarah; Puig, Pere; Masqué, Pere; Juan-Díaz, Xènia; Martín, Jacobo; Palanques, Albert

2017-01-01

Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of canyons’ morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20th century, these sedimentary alterations may occur in many trawled canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities. PMID:28233856

Bottom-trawling along submarine canyons impacts deep sedimentary regimes

NASA Astrophysics Data System (ADS)

Paradis, Sarah; Puig, Pere; Masqué, Pere; Juan-Díaz, Xènia; Martín, Jacobo; Palanques, Albert

2017-02-01

Many studies highlight that fish trawling activities cause seafloor erosion, but the assessment of the remobilization of surface sediments and its relocation is still not well documented. These impacts were examined along the flanks and axes of three headless submarine canyons incised on the Barcelona continental margin, where trawling fleets have been operating for decades. Trawled grounds along canyon flanks presented eroded and highly reworked surface sediments resulting from the passage of heavy trawling gear. Sedimentation rates on the upper canyon axes tripled and quadrupled its natural (i.e. pre-industrialization) values after a substantial increase in total horsepower of the operating trawling fleets between 1960 s and 1970 s. These impacts affected the upper canyon reaches next to fishing grounds, where sediment resuspended by trawling can be transported towards the canyon axes. This study highlights that bottom trawling has the capacity to alter natural sedimentary environments by promoting sediment-starved canyon flanks, and by enhancing sedimentation rates along the contiguous axes, independently of canyons’ morphology. Considering the global mechanisation and offshore expansion of bottom trawling fisheries since the mid-20th century, these sedimentary alterations may occur in many trawled canyons worldwide, with further ecological impacts on the trophic status of these non-resilient benthic communities.

High diet overlap between native small-bodied fishes and nonnative fathead minnow in the Colorado River, Grand Canyon, Arizona

USGS Publications Warehouse

Seegert, Sarah E. Zahn; Rosi-Marshall, Emma J.; Baxter, Colden V.; Kennedy, Theodore A.; Hall, Robert O.; Cross, Wyatt F.

2014-01-01

River regulation may mediate the interactions among native and nonnative species, potentially favoring nonnative species and contributing to the decline of native populations. We examined food resource use and diet overlap among small-bodied fishes in the Grand Canyon section of the Colorado River as a first step in evaluating potential resource competition. We compared the diets of the predominant small-bodied fishes (native Speckled Dace Rhinichthys osculus, juvenile Flannelmouth Sucker Catostomus latipinnis, and juvenile Bluehead Sucker C. discobolus, and nonnative Fathead Minnow Pimephales promelas) across seasons at four sites downstream of Glen Canyon Dam using nonmetric multidimensional scaling and Schoener's similarity index. The diets of these fishes included diatoms, amorphous detritus, aquatic invertebrates (especially simuliid and chironomid larvae), terrestrial invertebrates, and terrestrial vegetation. Diets varied with season and were affected by high turbidity. Fish consumed more amorphous detritus and terrestrial vegetation during the summer monsoon season (July–September), when turbidity was higher. The diets of all species overlapped, but there was large variation in the degree of overlap. The diets of juvenile suckers and Fathead Minnows were most similar, while Speckled Dace had relatively distinct diets. The differences took the form of higher proportions of diatoms and amorphous detritus in the diets of Bluehead Suckers and Fathead Minnows and higher proportions of simuliids and chironomids in those of Speckled Dace. If food resources are or become limiting, diet overlap suggests that competition may occur among native and nonnative species, which could have implications for the population dynamics of these fishes and for the management of the Colorado River ecosystem in Grand Canyon.

Active geologic processes in Barrow Canyon, northeast Chukchi Sea

USGS Publications Warehouse

Eittreim, S.; Grantz, A.; Greenberg, J.

1982-01-01

Circulation patterns on the shelf and at the shelf break appear to dominate the Barrow Canyon system. The canyon's shelf portion underlies and is maintained by the Alaska Coastal Current (A.C.C.), which flows northeastward along the coast toward the northeast corner of the broad Chukchi Sea. Offshelf and onshelf advective processes are indicated by oceanographic measurements of other workers. These advective processes may play an important role in the production of bedforms that are found near the canyon head as well as in processes of erosion or non-deposition in the deeper canyon itself. Coarse sediments recovered from the canyon axis at 400 to 570 m indicate that there is presently significant flow along the canyon. The canyon hooks left at a point north of Point Barrow where the A.C.C. loses its coastal constriction. The left hook, as well as preferential west-wall erosion, continues down to the abyssal plain of the Canada Basin at 3800 m. A possible explanation for the preferential west-wall erosion along the canyon, at least for the upper few hundred meters, is that the occasional upwelling events, which cause nutrient-rich water to flow along the west wall would in turn cause larger populations of burrowing organisms to live there than on the east wall, and that these organisms cause high rates of bioerosion. This hypothesis assumes that the dominant factor in the canyon's erosion is biological activity, not current velocity. Sedimentary bedforms consisting of waves and furrows are formed in soft mud in a region on the shelf west of the canyon head; their presence there perhaps reflects: (a) the supply of fine suspended sediments delivered by the A.C.C. from sources to the south, probably the Yukon and other rivers draining northwestern Alaska; and (b) the westward transport of these suspended sediments by the prevailing Beaufort Gyre which flows along the outer shelf. ?? 1982.

Dam removal: Listening in

NASA Astrophysics Data System (ADS)

Foley, M. M.; Bellmore, J. R.; O'Connor, J. E.; Duda, J. J.; East, A. E.; Grant, G. E.; Anderson, C. W.; Bountry, J. A.; Collins, M. J.; Connolly, P. J.; Craig, L. S.; Evans, J. E.; Greene, S. L.; Magilligan, F. J.; Magirl, C. S.; Major, J. J.; Pess, G. R.; Randle, T. J.; Shafroth, P. B.; Torgersen, C. E.; Tullos, D.; Wilcox, A. C.

2017-07-01

Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings. Based on dam removals thus far, some general conclusions have emerged: (1) physical responses are typically fast, with the rate of sediment erosion largely dependent on sediment characteristics and dam-removal strategy; (2) ecological responses to dam removal differ among the affected upstream, downstream, and reservoir reaches; (3) dam removal tends to quickly reestablish connectivity, restoring the movement of material and organisms between upstream and downstream river reaches; (4) geographic context, river history, and land use significantly influence river restoration trajectories and recovery potential because they control broader physical and ecological processes and conditions; and (5) quantitative modeling capability is improving, particularly for physical and broad-scale ecological effects, and gives managers information needed to understand and predict long-term effects of dam removal on riverine ecosystems. Although these studies collectively enhance our understanding of how riverine ecosystems respond to dam removal, knowledge gaps remain because most studies have been short (< 5 years) and do not adequately represent the diversity of dam types, watershed conditions, and dam-removal methods in the U.S.

Dam removal: Listening in

USGS Publications Warehouse

Foley, Melissa M.; Bellmore, James; O'Connor, James E.; Duda, Jeff; East, Amy E.; Grant, Gordon G.; Anderson, Chauncey; Bountry, Jennifer A.; Collins, Mathias J.; Connolly, Patrick J.; Craig, Laura S.; Evans, James E.; Greene, Samantha; Magilligan, Francis J.; Magirl, Christopher S.; Major, Jon J.; Pess, George R.; Randle, Timothy J.; Shafroth, Patrick B.; Torgersen, Christian E.; Tullos, Desiree D.; Wilcox, Andrew C.

2017-01-01

Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings. Based on dam removals thus far, some general conclusions have emerged: (1) physical responses are typically fast, with the rate of sediment erosion largely dependent on sediment characteristics and dam-removal strategy; (2) ecological responses to dam removal differ among the affected upstream, downstream, and reservoir reaches; (3) dam removal tends to quickly reestablish connectivity, restoring the movement of material and organisms between upstream and downstream river reaches; (4) geographic context, river history, and land use significantly influence river restoration trajectories and recovery potential because they control broader physical and ecological processes and conditions; and (5) quantitative modeling capability is improving, particularly for physical and broad-scale ecological effects, and gives managers information needed to understand and predict long-term effects of dam removal on riverine ecosystems. Although these studies collectively enhance our understanding of how riverine ecosystems respond to dam removal, knowledge gaps remain because most studies have been short (< 5 years) and do not adequately represent the diversity of dam types, watershed conditions, and dam-removal methods in the U.S.

Dam removal: Listening in

Treesearch

M. M. Foley; J. R. Bellmore; J. E. O' Connor; J. J. Duda; A. E. East; G. E. Grant; C. W. Anderson; J. A. Bountry; M. J. Collins; P. J. Connolly; L. S. Craig; J. E. Evans; S. L. Greene; F. J. Magilligan; C. S. Magirl; J. J. Major; G. R. Pess; T. J. Randle; P. B. Shafroth; C. E. Torgersen; D. Tullos; A. C. Wilcox

2017-01-01

Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings....

Perspective view over the Grand Canyon, Arizona

NASA Image and Video Library

2001-10-22

This simulated true color perspective view over the Grand Canyon was created from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data acquired on May 12, 2000. The Grand Canyon Village is in the lower foreground; the Bright Angel Trail crosses the Tonto Platform, before dropping down to the Colorado Village and then to the Phantom Ranch (green area across the river). Bright Angel Canyon and the North Rim dominate the view. At the top center of the image the dark blue area with light blue haze is an active forest fire. http://photojournal.jpl.nasa.gov/catalog/PIA01908

6. DARK CANYON SIPHON Photographic copy of historic photo, ...

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

6. DARK CANYON SIPHON - Photographic copy of historic photo, January 29, 1907 (original print filed in Record Group 115, National Archives, Washington, D.C.) W.J.Lubken, photographer 'RIPRAP AT THE ENTRANCE END OF DARK CANYON PRESSURE PIPE' - Carlsbad Irrigation District, Dark Canyon Siphon, On Main Canal, 1 mile South of Carlsbad, Carlsbad, Eddy County, NM

Dam failure analysis for the Lago El Guineo Dam, Orocovis, Puerto Rico

USGS Publications Warehouse

Gómez-Fragoso, Julieta; Heriberto Torres-Sierra,

2016-08-09

The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed hydrologic and hydraulic analyses to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago El Guineo Dam. The Lago El Guineo Dam is within the headwaters of the Río Grande de Manatí and impounds a drainage area of about 4.25 square kilometers.The hydrologic assessment was designed to determine the outflow hydrographs and peak discharges for Lago El Guineo and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation event, (2) a 24-hour probable maximum precipitation event, and (3) a 24-hour, 100-year recurrence rainfall event. The hydraulic study simulated a dam failure of Lago El Guineo Dam using flood hydrographs generated from the hydrologic study. The simulated dam failure generated a hydrograph that was routed downstream from Lago El Guineo Dam through the lower reaches of the Río Toro Negro and the Río Grande de Manatí to determine water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” conditions. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC–HMS) and Hydrologic Engineering Center’s River Analysis System (HEC–RAS) computer programs, developed by the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively. The flow routing in the hydraulic analyses was completed using the unsteady flow module available in the HEC–RAS model.Above the Lago El Guineo Dam, the simulated inflow peak discharges from HEC–HMS resulted in about 550 and 414 cubic meters per second for the 6- and 24-hour probable maximum precipitation events, respectively. The 24-hour, 100-year recurrence storm simulation resulted in a peak discharge of about 216 cubic meters per second. For the hydrologic analysis, no dam failure conditions are

Amphitheater-headed canyons formed by megaflooding at Malad Gorge, Idaho

PubMed Central

Lamb, Michael P.; Mackey, Benjamin H.; Farley, Kenneth A.

2014-01-01

Many bedrock canyons on Earth and Mars were eroded by upstream propagating headwalls, and a prominent goal in geomorphology and planetary science is to determine formation processes from canyon morphology. A diagnostic link between process and form remains highly controversial, however, and field investigations that isolate controls on canyon morphology are needed. Here we investigate the origin of Malad Gorge, Idaho, a canyon system cut into basalt with three remarkably distinct heads: two with amphitheater headwalls and the third housing the active Wood River and ending in a 7% grade knickzone. Scoured rims of the headwalls, relict plunge pools, sediment-transport constraints, and cosmogenic (3He) exposure ages indicate formation of the amphitheater-headed canyons by large-scale flooding ∼46 ka, coeval with formation of Box Canyon 18 km to the south as well as the eruption of McKinney Butte Basalt, suggesting widespread canyon formation following lava-flow diversion of the paleo-Wood River. Exposure ages within the knickzone-headed canyon indicate progressive upstream younging of strath terraces and a knickzone propagation rate of 2.5 cm/y over at least the past 33 ka. Results point to a potential diagnostic link between vertical amphitheater headwalls in basalt and rapid erosion during megaflooding due to the onset of block toppling, rather than previous interpretations of seepage erosion, with implications for quantifying the early hydrosphere of Mars. PMID:24344293

Crossing fitness canyons by a finite population

NASA Astrophysics Data System (ADS)

Saakian, David B.; Bratus, Alexander S.; Hu, Chin-Kun

2017-06-01

We consider the Wright-Fisher model of the finite population evolution on a fitness landscape defined in the sequence space by a path of nearly neutral mutations. We study a specific structure of the fitness landscape: One of the intermediate mutations on the mutation path results in either a large fitness value (climbing up a fitness hill) or a low fitness value (crossing a fitness canyon), the rest of the mutations besides the last one are neutral, and the last sequence has much higher fitness than any intermediate sequence. We derive analytical formulas for the first arrival time of the mutant with two point mutations. For the first arrival problem for the further mutants in the case of canyon crossing, we analytically deduce how the mean first arrival time scales with the population size and fitness difference. The location of the canyon on the path of sequences has a crucial role. If the canyon is at the beginning of the path, then it significantly prolongs the first arrival time; otherwise it just slightly changes it. Furthermore, the fitness hill at the beginning of the path strongly prolongs the arrival time period; however, the hill located near the end of the path shortens it. We optimize the first arrival time by applying a nonzero selection to the intermediate sequences. We extend our results and provide a scaling for the valley crossing time via the depth of the canyon and population size in the case of a fitness canyon at the first position. Our approach is useful for understanding some complex evolution systems, e.g., the evolution of cancer.

[Effect of greenbelt on pollutant dispersion in street canyon].

PubMed

Xu, Wei-Jia; Xing, Hong; Yu, Zhi

2012-02-01

The effect feature of greenbelt on flow field and pollutant dispersion in urban street canyon was researched. The greenbelt was assumed as uniform porous media and its aerodynamics property defined by the pressure loss coefficient. Subsequently, the pollutant dispersion in the street canyon of which there was greenbelt in the middle was simulated with the steady-state standard kappa-epsilon turbulence model and species transport equation. The simulated results agreed well with the wind-tunnel data. Compared with the treeless case, it finds that the street canyon contain a clockwise vortex, the pollutant concentration of the leeward was several times than the windward and the growth rate of pollutant concentration was 46.0%. The further simulation for the impact of tree crown position on the airflow and pollutant dispersion finds that the height of major vortex center in the street canyon increases with the height of tree crown and gradually closes the top of windward building This causes that the average wind speed in the street canyon decreases. Especially when the top of tree crown over the roof and hinder the air flow above the street canyon, the average pollutant concentration increases with the height of tree crown rapidly.

Dam failure analysis for the Lago de Matrullas Dam, Orocovis, Puerto Rico

USGS Publications Warehouse

Torres-Sierra, Heriberto; Gómez-Fragoso, Julieta

2015-01-01

Results from the simulated dam failure of the Lago de Matrullas Dam using the HEC–RAS model for the 6- and 24-hour PMP events showed peak discharges at the dam of 3,149.33 and 3,604.70 m3/s, respectively. Dam failure during the 100-year-recurrence, 24-hour rainfall event resulted in a peak discharge of 2,103.12 m3/s directly downstream from the dam. Dam failure under sunny day conditions produced a peak discharge of 1,695.91 m3/s at the dam assuming the antecedent lake level was at the morning-glory spillway invert elevation. Flood-inundation maps prepared as part of the study depict the flood extent and provide valuable information for preparing an Emergency Action Plan. Results of the failure analysis indicate that a failure of the Lago de Matrullas Dam could cause flooding to many of the inhabited areas along stream banks from the Lago de Matrullas Dam to the mouth of the Río Grande de Manatí. Among the areas most affected are the low-lying regions in the vicinity of the towns of Ciales, Manatí, and Barceloneta. The delineation of the flood boundaries near the town of Barceloneta considered the effects of a levee constructed during 2000 at Barceloneta in the flood plain of the Río Grande de Manatí to provide protection against flooding to the near-by low-lying populated areas. The results showed overtopping can be expected in the aforementioned levee during 6- and 24-hour probable-maximum-precipitation dam failure scenarios. No overtopping of the levee was simulated, however, during dam failure scenarios under the 100-year recurrence, 24-hour rainfall event or sunny day conditions.

A simulation study of factors controlling white sturgeon recruitment in the Snake River

USGS Publications Warehouse

Jager, H.I.; Van Winkle, W.; Chandler, James Angus; Lepla, K.B.; Bates, P.; Counihan, T.D.

2002-01-01

Five of the nine populations of white sturgeon Acipenser transmontanus, located between dams on the Middle Snake River, have declined from historical levels and are now at risk of extinction. One step towards more effectively protecting and managing these nine populations is ranking factors that influence recruitment in each of these river segments. We developed a model to suggest which of seven mechanistic factors contribute most to lost recruitment in each river segment: (1) temperature-related mortality during incubation, (2) flow-related mortality during incubation, (3) downstream export of larvae, (4) limitation of juvenile and adult habitat, (5) mortality of all ages during summer episodes of poor water quality in reservoirs, (6) entrainment mortality of juveniles and adults, and (7) angling mortality. We simulated recruitment with, and without, each of the seven factors, over a typical series of hydrologic years. We found a hierarchical pattern of limitation. In the first tier, river segments with severe water quality problems grouped together. Poor water quality during summer had a strong negative effect on recruitment in the river segments between Swan Falls Dam and Hell's Canyon Dam. In the second tier, river segments with better water quality divided into short river segments and longer river segments. Populations in short river segments were limited by larval export. Populations in longer river segments tended to be less strongly limited by any one factor. We also found that downstream effects could be important, suggesting that linked populations cannot be viewed in isolation. In two cases, the effects of a factor on an upstream population had a significant influence on its downstream neighbors. ?? 2002 by the American Fisheries Society.

Cyclic aggradation and downcutting, fluvial response to volcanic activity, and calibration of soil-carbonate stages in the western Grand Canyon, Arizona

USGS Publications Warehouse

Lucchitta, Ivo; Curtis, Garniss H.; Davis, Marie E.; Davis, Sidney W.; Turrin, Brent

2000-01-01

In the western Grand Canyon, fluvial terraces and pediment surfaces, both associated with a Pleistocene basalt flow, document Quaternary aggradation and downcutting by the Colorado River, illuminate the river's response to overload and the end of overload, and allow calibration of soil-carbonate stages and determination of downcutting rates. Four downcutting-aggradation cycles are present. Each begins with erosion of older deposits to form a new river channel in which a characteristic suite of deposits is laid down. The current cycle (I) started ~700 yr B.P. The oldest (IV) includes the 603,000 ± 8000 to 524,000 ± 7000 yr Black Ledge basalt flow, emplaced when the river channel was ~30 m higher than it is now. The flow is overlain by basalt-cobble gravel and basalt sand. Soils reach the stage V level of carbonate development. Calibrated ages for soil stages are Stage V, ~525,000 yr; stage IV, <525,000 yr, ≥250,000 yr; stage III, <250,000 yr, ≥100,000 yr. The monolithologic basalt sand beds represent overloading by volcanic ash produced by an eruption 30-50 km upstream. The basalt-cobble beds signal breaching and rapid destruction of lava dams and erosion of flows. These deposits show that the Colorado River responds to overload by aggrading vigorously during the overload and then downcutting equally vigorously when the overload ends. The overall downcutting rate for the interval studied is 1.6 cm/1000 yr, much lower than rates upstream. The current downcutting rate, 11-14 m/1000 yr, likely is a response both to the end of late Pleistocene and early Holocene overload and to the reduction of sediment supply caused by Glen Canyon Dam.

Geomorphic Thresholds of Submarine Canyons Along the U.S. Atlantic Continental Margin

NASA Astrophysics Data System (ADS)

Brothers, D. S.; ten Brink, U. S.; Andrews, B. D.; Chaytor, J. D.

2011-12-01

Vast networks of submarine canyons and associated channels are incised into the U.S. Atlantic continental slope and rise. Submarine canyons form by differential erosion and deposition, primarily from sedimentary turbidity flows. Theoretical and laboratory studies have investigated the initiation of turbidity flows and their capacity to erode and entrain sedimentary material at distances far from the shelf edge. The results have helped understand the nature of turbidite deposits on the continental slope and rise. Nevertheless, few studies have examined the linkages between down-canyon sediment transport and the morphology of canyon/channel networks using mesoscale analyses of swath bathymetry data. We present quantitative analysis of 100-m resolution multibeam bathymetry data spanning ~616,000 km2 of the slope and rise between Georges Banks and the Blake Plateau (New England to North Carolina). Canyons are categorized as shelf-indenting or slope-confined based on spatial scale, vertical relief and connection with terrestrial river systems during sea level low stands. Shelf-indenting canyons usually represent the trunk-canyon of submerged channel networks. On the rise, shelf-indenting canyons have relatively well-developed channel-levees and sharp inner-thalwag incision suggesting much higher frequency and volume of turbidity flows. Because of the similarities between submarine canyon networks and terrestrial river systems, we apply methods originally developed to study fluvial morphology. Along-canyon profiles are extracted from the bathymetry data and the power-law relationship between thalwag gradient and drainage area is examined for more than 180 canyons along an ~1200 km stretch of the US Atlantic margin. We observe distinct thresholds in the power-law relationship between drainage area and gradient. Almost all canyons with heads on the upper slope contain at least two linear segments when plotted in log-log form. The first segment along the upper slope is flat

Spatial and Temporal Variation in DeSoto Canyon Macrofaunal Community Structure

NASA Astrophysics Data System (ADS)

Baco-Taylor, A.; Shantharam, A. K.

2016-02-01

Sediment-dwelling macrofauna (polychaetes, bivalves, and assorted crustaceans ≥ 300 µm) have long served as biological indicators of ecosystem stress. As part of evaluating the 2010 impact from the Deepwater Horizon blowout, we sampled 12 sites along and transverse to the DeSoto Canyon axis, Gulf of Mexico, as well as 2 control sites outside the Canyon. Sites ranged in depth from 479-2310 m. Three of the sites (PCB06, S36, and XC4) were sampled annually from 2012-2014. We provide an overview of the macrofauna community structure of canyon and non-canyon sites, as well as trends in community structure and diversity at the time-series sites. Compositionally, polychaetes dominated the communities, followed by tanaid crustaceans and bivalves. The total number of individuals was not significantly correlated with depth while the total number of taxa and species richness were. Rarefaction shows the deepest station, XC4 (2310 m) had the lowest diversity while NT800 (a non-canyon control at 800m) had the highest. Multivariate analysis shows the canyon assemblages fall into eight clusters with the non-canyon stations forming a separate ninth cluster, indicating a detectable difference in canyon and non-canyon communities. Time series stations show an increase in diversity from 2012-2014 with a strong overlap in community structure in 2013 and 2014 samples. Environmental analysis, via BEST, using data from 10 canyon sites and the controls, indicated depth in combination with latitude explain the most variation in macrofaunal community structure.

NASA Satellite Reveals Grandeur of Arizona Grand Canyon

NASA Image and Video Library

2011-10-14

Arguably one of America most magnificent national parks is the Grand Canyon in northern Arizona. NASA Terra spacecraft captured this image looking to the northeast, the buildings and roads in the center foreground are Grand Canyon Village.

Distribution and transport of suspended particulate matter in Monterey Canyon, California

USGS Publications Warehouse

Xu, J. P.; Noble, M.; Eittreim, S.L.; Rosenfeld, L.K.; Schwing, F.B.; Pilskaln, C.H.

2002-01-01

From August 1993 to August 1994, six moorings that measure current, temperature, salinity, and water clarity were deployed along the axis of Monterey Canyon to study the circulation and transport of water and suspended particulate matter through the canyon system. The moorings occupied three sites that are morphologically different: a narrow transverse section (axis width 900 m) at 1450 m water depth, a wide transverse section at 2837 m, and a third site in the fan valley axis farther offshore at 3223 m that recorded for 3 yr. In addition, CTD/transmissometer casts were conducted within and near the Monterey Canyon during four cruises. Our data show a mainly biogenic, surface turbid layer, a limited intermediate nepheloid layer, and a bottom nepheloid layer. There is a consistent presence of a turbid layer within the canyon at a water depth of about 1500 m. Tidal flow dominates at all sites, but currents above the canyon rim and within the canyon appear to belong to two distinct dynamic systems. Bottom intensification of currents plays an important role in raising the near-bottom shear stress high enough that bottom sediments are often, if not always, resuspended. Mean flow pattern suggests a convergence zone between the narrow and wide site: the near-bed (100 m above bottom where the lowest current meter was located) mean transport is down-canyon at the 1450-m site, while the near-bottom transport at the 2837-m site is up-canyon, at a smaller magnitude. Transport at the 3223-m site is dominantly NNW, cross-canyon, with periods of up-canyon flow over 3 yr. A very high-turbidity event was recorded 100 m above the canyon bottom at the narrow site. The event started very abruptly and lasted more than a week. This event was not detected at either of the deeper sites. A canyon head flushing event is likely the cause. ?? 2002 Elsevier Science B.V. All rights reserved.

Strategic guidelines for street canyon geometry to achieve sustainable street air quality

NASA Astrophysics Data System (ADS)

Chan, Andy T.; So, Ellen S. P.; Samad, Subash C.

This paper is concerned with the motion of air within the urban street canyon and is directed towards a deeper understanding of pollutant dispersion with respect to various simple canyon geometries and source positions. Taking into account the present days typical urban configurations, three principal flow regimes "isolated roughness flow", "skimming flow" and "wake interference flow" (Boundary Layer Climates, 2nd edition, Methuen, London) and their corresponding pollutant dispersion characteristics are studied for various canopies aspect ratios, namely relative height ( h2/ h1), canyon height to width ratio ( h/ w) and canyon length to height ratio ( l/ h). A field-size canyon has been analyzed through numerical simulations using the standard k- ɛ turbulence closure model. It is found that the pollutant transport and diffusion is strongly dependent upon the type of flow regime inside the canyon and exchange between canyon and the above roof air. Some rules of thumbs have been established to get urban canyon geometries for efficient dispersion of pollutants.

Geology of the head of Lydonia Canyon, U.S. Atlantic outer continental shelf

USGS Publications Warehouse

Twichell, David C.

1983-01-01

The geology of the part of Lydonia Canyon shoreward of the continental shelf edge on the southern side of Georges Bank was mapped using high-resolution seismic-reflection and side-scan sonar techniques and surface sediment grab samples. The head of the canyon incises Pleistocene deltaic deposits and Miocene shallow marine strata. Medium sand containing some coarse sand and gravel covers the shelf except for a belt of very fine sand containing no gravel on either side of the canyon in water depths of 125–140 m. Gravel and boulders, presumably ice-rafted debris, cover the rim of the canyon. The canyon floor and canyon wall gullies are covered by coarse silt of Holocene age which is as much as 25 m thick, and Miocene and Pleistocene strata are exposed on the spurs between gullies. The Holocene sediment is restricted to the canyon shoreward of the shelf edge and has been winnowed from the shelf. Furrows cut in the shelf sands and ripples on the shelf and in the canyon suggest that sediment continues to be moved in this area. Sediment distribution, however, is inconsistent with that expected from the inferred westward sediment transport on the shelf. Either the fine-grained deposits on the shelf to either side of the canyon head are relict or there is a significant component of offshore transport around the canyon head.In the head of Oceanographer Canyon, only 40 km west of Lydonia Canyon, present conditions are strikingly different. The floor of Oceanographer Canyon is covered by sand waves, and their presence indicates active reworking of the bottom sediments by strong currents. The close proximity of the two canyons suggests that the relative importance of processes acting in canyons can be variable over short distances.

H CANYON PROCESSING IN CORRELATION WITH FH ANALYTICAL LABS

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

Weinheimer, E.

2012-08-06

Management of radioactive chemical waste can be a complicated business. H Canyon and F/H Analytical Labs are two facilities present at the Savannah River Site in Aiken, SC that are at the forefront. In fact H Canyon is the only large-scale radiochemical processing facility in the United States and this processing is only enhanced by the aid given from F/H Analytical Labs. As H Canyon processes incoming materials, F/H Labs provide support through a variety of chemical analyses. Necessary checks of the chemical makeup, processing, and accountability of the samples taken from H Canyon process tanks are performed at themore » labs along with further checks on waste leaving the canyon after processing. Used nuclear material taken in by the canyon is actually not waste. Only a small portion of the radioactive material itself is actually consumed in nuclear reactors. As a result various radioactive elements such as Uranium, Plutonium and Neptunium are commonly found in waste and may be useful to recover. Specific processing is needed to allow for separation of these products from the waste. This is H Canyon's specialty. Furthermore, H Canyon has the capacity to initiate the process for weapons-grade nuclear material to be converted into nuclear fuel. This is one of the main campaigns being set up for the fall of 2012. Once usable material is separated and purified of impurities such as fission products, it can be converted to an oxide and ultimately turned into commercial fuel. The processing of weapons-grade material for commercial fuel is important in the necessary disposition of plutonium. Another processing campaign to start in the fall in H Canyon involves the reprocessing of used nuclear fuel for disposal in improved containment units. The importance of this campaign involves the proper disposal of nuclear waste in order to ensure the safety and well-being of future generations and the environment. As processing proceeds in the fall, H Canyon will have a

Conditions and processes affecting sand resources at archeological sites in the Colorado River corridor below Glen Canyon Dam, Arizona

USGS Publications Warehouse

East, Amy E.; Collins, Brian D.; Sankey, Joel B.; Corbett, Skye C.; Fairley, Helen C.; Caster, Joshua J.

2016-05-17

We conclude that most of the river-corridor archeological sites are at elevated risk of net erosion under present dam operations. In the present flow regime, controlled floods do not simulate the magnitude or frequency of natural floods, and are not large enough to deposit sand at elevations that were flooded at annual to decadal intervals in predam time. For archeological sites that depend upon river-derived sand, we infer elevated erosion risk owing to a combination of reduced sand supply (both fluvial and aeolian) through (1) the lower-than-natural flood magnitude, frequency, and sediment supply of the controlled-flooding protocol; (2) reduction of open, dry sand area available for wind redistribution under current normal (nonflood) dam operations, which do not include flows as low as natural seasonal low flows and do include substantial daily flow fluctuations; and (3) impeded aeolian sand entrainment and transport owing to increased riparian vegetation growth in the absence of larger, more-frequent floods. If dam operations were to increase the supply of sand available for windblown transport—for example, through larger floods, sediment augmentation, or increased fluvial sandbar exposure by low flows—and also decrease riparian vegetation, the prevalence of active aeolian sand could increase over time, and the propensity for unmitigated gully erosion could decrease. Although the evolution of river-corridor landscapes and archeological sites has been altered fundamentally by the lack of large, sediment-rich floods (flows on the order of 5,000 m3/s), some combination of sediment-rich flows above 1,270 m3/s, seasonal flows below 226 m3/s, and riparian-vegetation removal might increase the preservation potential for sand-dependent archeological resources in the Colorado River corridor.

27 CFR 9.152 - Malibu-Newton Canyon.

Code of Federal Regulations, 2010 CFR

2010-04-01

....” (2) Then south along Kanan Dume Road to the point where an unnamed, unimproved dirt road referred to... Canyon Road to an unnamed, unimproved dirt road referred to by the petitioner as Newton Mountain Way at... southeastern ridgeline of Newton Canyon, to an unnamed, unimproved dirt road referred to by the petitioner as...

Sediment Dating With 210Pb and 137Cs In Monterey Canyon, California Reveal the extent of recent sediment movement down canyon

NASA Astrophysics Data System (ADS)

Lorenson, T. D.; Maier, K. L.; Gwiazda, R.; Paull, C. K.; McGann, M.

2017-12-01

Submarine canyons are major vectors of sediment transport off the continent into the deep sea. Recent results from the Monterey Coordinated Canyon Experiment document fifteen sediment transport events occurred during an 18-month period from 2015 to 2017, and three of them reached at least to 1850m. In an attempt to constrain the timing and rate in which sediments were transported down canyons in these and earlier events we have collected sediment cores and measured the sedimentation rates using 210Pb and 137Cs dating techniques along the axis of Monterey Canyon. We employed transects of precisely located ROV collected push cores and vibracores collected at water depths ranging from 300m to 2900m perpendicular to the canyon axis using a remotely operated vehicle (ROV). Some cores were taken in 2013 and compared with those taken in 2017. We focused on cores from terraces that are between 60m and 75m above the canyon thalweg in water depths between 300 and 1500 m and in cores collected form the canyon's axial channel between 1800 and 2900 m water depths where the canyon widens considerably. Generally sedimentation rates vary with depth, with the highest sedimentation rate closest to land, but vary substantially across successive terraces. Sawtooth-shaped excess 210Pb and 137Cs profiles with depth at almost all sites at least to 1500m imply several episodes of deposition and reworking of sediment on the terraces suggesting multiple sediment transport events. The excess 210Pb in many cores reach depths of up to 1m implying sedimentation rates greater than 10mm per year. At the deepest site (2900m) about 10 cm of fine hemipelagic sediment overlies sand indicating a high-energy sediment flow event. In 2014 the measured 210Pb sedimentation rate of 0.6 to 0.8mm per year indicates that the last 10 cm of sediment have been deposited and undisturbed since about the year 1910 showing that recent events have not reached this depth. Measurements are on going to determine if the

Dispersion and photochemical evolution of reactive pollutants in street canyons

NASA Astrophysics Data System (ADS)

Kwak, Kyung-Hwan; Baik, Jong-Jin; Lee, Kwang-Yeon

2013-05-01

Dispersion and photochemical evolution of reactive pollutants in street canyons with canyon aspect ratios of 1 and 2 are investigated using a computational fluid dynamics (CFD) model coupled with the carbon bond mechanism IV (CBM-IV). Photochemical ages of NOx and VOC are expressed as a function of the NO2-to-NOx and toluene-to-xylene ratios, respectively. These are found to be useful for analyzing the O3 and OH oxidation processes in the street canyons. The OH oxidation process (O3 oxidation process) is more pronounced in the upper (lower) region of the street canyon with a canyon aspect ratio of 2, which is characterized by more (less) aged air. In the upper region of the street canyon, O3 is chemically produced as well as transported downward across the roof level, whereas O3 is chemically reduced in the lower region of the street canyon. The O3 chemical production is generally favorable when the normalized photochemical ages of NOx and VOC are larger than 0.55 and 0.28, respectively. The sensitivities of O3 chemical characteristics to NOx and VOC emission rates, photolysis rate, and ambient wind speed are examined for the lower and upper regions of the street canyon with a canyon aspect ratio of 2. The O3 concentration and the O3 chemical production rate divided by the O3 concentration increase as the NOx emission rate decreases and the VOC emission rate and photolysis rate increase. The O3 concentration is less sensitive to the ambient wind speed than to other factors considered. The relative importance of the OH oxidation process compared to the O3 oxidation process increases with increasing NOx emission rate and photolysis rate and decreasing VOC emission rate. In this study, both O3 and OH oxidation processes are found to be important in street-canyon scale chemistry. The methodology of estimating the photochemical ages can potentially be adopted to neighborhood scale chemistry.

Dam break analysis and flood inundation map of Krisak dam for emergency action plan

NASA Astrophysics Data System (ADS)

Juliastuti, Setyandito, Oki

2017-11-01

The Indonesian Regulation which refers to the ICOLD Regulation (International Committee on Large Dam required have the Emergency Action Plan (EAP) guidelines because of the dams have potential failure. In EAP guidelines there is a management of evacuation where the determination of the inundation map based on flood modeling. The purpose of the EAP is to minimize the risk of loss of life and property in downstream which caused by dam failure. This paper will describe about develop flood modeling and inundation map in Krisak dam using numerical methods through dam break analysis (DBA) using hydraulic model Zhong Xing HY-21. The approaches of dam failure simulation are overtopping and piping. Overtopping simulation based on quadrangular, triangular and trapezium fracture. Piping simulation based on cracks of orifice. Using results of DBA, hazard classification of Krisak dam is very high. The nearest village affected dam failure is Singodutan village (distance is 1.45 kilometer from dam) with inundation depth is 1.85 meter. This result can be used by stakeholders such as emergency responders and the community at risk in formulating evacuation procedure.

How big of an effect do small dams have? Using geomorphological footprints to quantify spatial impact of low-head dams and identify patterns of across-dam variation

USGS Publications Warehouse

Fencl, Jane S.; Mather, Martha E.; Costigan, Katie H.; Daniels, Melinda D.

2015-01-01

Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (<7.6 m high) fragment United States rivers. Despite potential adverse impacts of these ubiquitous disturbances, the spatial impacts of low-head dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0–15.3 km) or 287 wetted widths (136–437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic

How Big of an Effect Do Small Dams Have? Using Geomorphological Footprints to Quantify Spatial Impact of Low-Head Dams and Identify Patterns of Across-Dam Variation

PubMed Central

Costigan, Katie H.; Daniels, Melinda D.

2015-01-01

Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (<7.6 m high) fragment United States rivers. Despite potential adverse impacts of these ubiquitous disturbances, the spatial impacts of low-head dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0–15.3 km) or 287 wetted widths (136–437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic

Physiographic rim of the Grand Canyon, Arizona: a digital database

USGS Publications Warehouse

Billingsley, George H.; Hampton, Haydee M.

1999-01-01

This Open-File report is a digital physiographic map database. This pamphlet serves to introduce and describe the digital data. There is no paper map included in the Open-File report. The report does include, however, PostScript and PDF format plot files, each containing an image of the map. For those interested in a paper plot of information contained in the database or in obtaining the PostScript plot files, please see the section entitled "For Those Who Don't Use Digital Geologic Map Databases" below. This physiographic map of the Grand Canyon is modified from previous versions by Billingsley and Hendricks (1989), and Billingsley and others (1997). The boundary is drawn approximately along the topographic rim of the Grand Canyon and its tributary canyons between Lees Ferry and Lake Mead (shown in red). Several isolated small mesas, buttes, and plateaus are within this area, which overall encompasses about 2,600 square miles. The Grand Canyon lies within the southwestern part of the Colorado Plateaus of northern Arizona between Lees Ferry, Colorado River Mile 0, and Lake Mead, Colorado River Mile 277. The Colorado River is the corridor for raft trips through the Grand Canyon. Limestone rocks of the Kaibab Formation form most of the north and south rims of the Grand Canyon, and a few volcanic rocks form the north rim of parts of the Uinkaret and Shivwits Plateaus. Limestones of the Redwall Limestone and lower Supai Group form the rim of the Hualapai Plateau area, and Limestones of Devonian and Cambrian age form the boundary rim near the mouth of Grand Canyon at the Lake Mead. The natural physiographic boundary of the Grand Canyon is roughly the area a visitor would first view any part of the Grand Canyon and its tributaries.

Shelf-Slope Exchanges near Submarine Canyons in the Southern Mid-Atlantic Bight

NASA Astrophysics Data System (ADS)

Wang, H.; Gong, D.

2016-02-01

Shelf-slope exchange processes are major physical drivers of biological productivity near the shelf-break. Observations from two Slocum ocean gliders in Fall 2013 are used to explore the driving mechanisms of cross-shelf-slope exchanges near Norfolk Canyon and Washington Canyon in the southern Mid-Atlantic Bight. Offshore excursion of bottom "cold pool" water, and shoreward intrusion of slope water at surface layer and thermocline depth occurred during northeasterly along-shelf winds. The saline intrusions of surface slope water resided between the cold pool and surface shelf water, and reached the bottom on the outer and mid-shelf, while the offshore excursion of cold pool water was found between the surface and intermediate slope-water over the canyon. Ekman transport calculation shows wind-driven cross-shelf transport can partially explain this interleaving pattern of intrusions. Scaling analysis of double diffusive processes demonstrate that they also likely played a role in the cross-shelf-slope exchange. A unique canyon upwelling event was captured in and around Washington Canyon during a period of southwesterly along-shelf wind and along-shelf flow to the northeast. The water mass distributions and isopycnal responses in both along-canyon and cross-canyon transects are consistent with scaling analysis and numerical studies of canyon upwelling. Temperature-Salinity properties of water masses in the canyon suggest active mixing between shelf and slope water masses near the canyon head. These results point to the importance of wind, double diffusion, and canyon topography on shelf-slope exchange in the MAB.

Monitoring and research to describe geomorphic effects of the 2011 controlled flood on the Green River in the Canyon of Lodore, Dinosaur National Monument, Colorado and Utah

USGS Publications Warehouse

Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Kaplinski, Matt; Alexander, Jason A.; Kohl, Keith

2014-01-01

In 2011, a large magnitude flow release from Flaming Gorge Reservoir, Wyoming and Utah, occurred in response to high snowpack in the middle Rocky Mountains. This was the third highest recorded discharge along the Green River downstream of Flaming Gorge Dam, Utah, since its initial closure in November 1962 and motivated a research effort to document effects of these flows on channel morphology and sedimentology at four long-term monitoring sites within the Canyon of Lodore in Dinosaur National Monument, Colorado and Utah. Data collected in September 2011 included raft-based bathymetric surveys, ground-based surveys of banks, channel cross sections and vegetation-plot locations, sand-bar stratigraphy, and painted rock recovery on gravel bars. As part of this surveying effort, Global Navigation Satellite System (GNSS) data were collected at benchmarks on the canyon rim and along the river corridor to establish a high-resolution survey control network. This survey control network allows for the collection of repeatable spatial and elevation data necessary for high accuracy geomorphic change detection. Nearly 10,000 ground survey points and more than 20,000 bathymetric points (at 1-meter resolution) were collected over a 5-day field campaign, allowing for the construction of reach-scale digital elevation models (DEMs). Additionally, we evaluated long-term geomorphic change at these sites using repeat topographic surveys of eight monumented cross sections at each of the four sites. Analysis of DEMs and channel cross sections show a spatially variable pattern of erosion and deposition, both within and between reaches. As much as 5 meters of scour occurred in pools downstream from flow constrictions, especially in channel segments where gravel bars were absent. By contrast, some channel cross sections were stable during the 2011 floods, and have shown almost no change in over a decade of monitoring. Partial mobility of gravel bars occurred, and although in some locations

Deformation Monitoring and Bathymetry Analyses in Rock-Fill Dams, a Case Study at Ataturk Dam

NASA Astrophysics Data System (ADS)

Kalkan, Y.; Bilgi, S.

2014-12-01

Turkey has 595 dams constructed between 1936 and 2013 for the purposes of irrigation, flood control, hydroelectric energy and drinking water. A major portion of the dam basins in Turkey are deprived of vegetation and have slope topography on near surrounding area. However, landscaping covered with forest around the dam basin is desirable for erosion control. In fact; the dams, have basins deprived of vegetation, fill up quickly due to sediment transport. Erosion control and forestation are important factors, reducing the sediment, to protect the water basins of the dams and increase the functioning life of the dams. The functioning life of dams is as important as the investment and construction. Nevertheless, in order to provide safety of human life living around, well planned monitoring is essential for dams. Dams are very large and critical structures and they demand the use or application of precise measuring systems. Some basic physical data are very important for assessing the safety and performance of dams. These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. Monitoring is an essential component of the dam after construction and during operation and must en­able the timely detection of any behavior that could deteriorate the dam, potentially result in its shutdown or failure. Considering the time and labor consumed by long-term measurements, processing and analysis of measured data, importance of the small structural motions at regular intervals could be comprehended. This study provides some information, safety and the techniques about the deformation monitoring of the dams, dam safety and related analysis. The case study is the deformation measurements of Atatürk Dam in Turkey which is the 6th largest dam of world considering the filling volume of embankment. Brief information is given about the

Evolution and Submarine Landslide Potential of Monterey Canyon Head, Offshore Central California

NASA Astrophysics Data System (ADS)

Maier, K. L.; Johnson, S. Y.; Hart, P. E.; Hartwell, S. R.

2016-12-01

Monterey Canyon, offshore central California, incises the shelf from near the shoreline to 30 km seaward where axial water depths approach 2,000 m. It is one of the world's most studied submarine canyons, yet debate continues concerning its age, formation, and associated geologic hazards. To address these issues, the USGS, with partial support from the California Seafloor Mapping Program, collected hundreds of kilometers of high-resolution, mini-sparker, single-channel (2009 and 2011 surveys) and multichannel (2015 survey) seismic-reflection profiles near the canyon head. The seismic data were combined with multibeam bathymetry to generate a geologic map of the proximal canyon, which delineates numerous faults and compound submarine landslide headwall scarps (covering up to 4 km2) along canyon walls. Seismic-reflection data reveal a massive ( 100 km2 lateral extent) paleochannel cut-and-fill complex underlying the proximal canyon. These subsurface cut-and-fill deposits span both sides of the relatively narrow modern canyon head, crop out in canyon walls, and incise into Purisima Formation (late Miocene and Pliocene) bedrock to depths of up to 0.3 s two-way travel time ( 240 m) below the modern shelf. We propose that the paleochannel complex represents previous locations of a migrating canyon head, and attribute its origin to multiple alternating cycles of fluvial and submarine canyon erosion and deposition linked to fluctuating sea levels. Thus, the canyon head imaged in modern bathymetry is a relatively young feature, perhaps forming in the last 20,000 years of sea-level rise. The paleocanyon deposits are significantly less consolidated than bedrock in deeper canyon walls, and therefore, are probably more prone to submarine landsliding. Nearby mapped faults occur within the active, distributed, San Andreas fault system, and earthquake-generated strong ground motions are likely triggers for past and future submarine landslides and potential associated tsunamis.

Westernmost Grand Canyon incision: Testing thermochronometric resolution

NASA Astrophysics Data System (ADS)

Fox, M.; Tripathy-Lang, A.; Shuster, D. L.; Winn, C.; Karlstrom, K.; Kelley, S.

2017-09-01

The timing of carving of Grand Canyon has been debated for over 100 years with competing endmember hypotheses advocating for either a 70 Ma ("old") or <6 Ma ("young") Grand Canyon. Several geological constraints appear to support a "young" canyon model, but thermochronometric measures of cooling history and corresponding estimates of landscape evolution have been in debate. In particular, 4He/3He thermochronometric data record the distribution of radiogenic 4He (from the 238U, 235U and 232Th decay series) within an individual apatite crystal and thus are highly sensitive to the thermal history corresponding to landscape evolution. However, there are several complicating factors that make interpreting such data challenging in geologic scenarios involving reheating. Here, we analyze new data that provide measures of the cooling of basement rocks at the base of westernmost Grand Canyon, and use these data as a testbed for exploring the resolving power and limitations of 4He/3He data in general. We explore a range of thermal histories and find that these data are most consistent with a "young" Grand Canyon. A problem with the recovered thermal history, however, is that burial temperatures are under predicted based on sedimentological evidence. A solution to this problem is to increase the resistance of alpha recoil damage to annealing, thus modifying He diffusion kinetics, allowing for higher temperatures throughout the thermal history. This limitation in quantifying radiation damage (and hence crystal retentivity) introduces non-uniqueness to interpreting time-temperature paths in rocks that resided in the apatite helium partial retention zone for long durations. Another source of non-uniqueness, is due to unknown U and Th distributions within crystals. We show that for highly zoned with a decrease in effective U of 20 ppm over the outer 80% of the radius of the crystal, the 4He/3He data could be consistent with an "old" canyon model. To reduce this non-uniqueness, we

Deep-Water Coral Diversity and Habitat Associations: Differences among Northeast Atlantic Submarine Canyons

NASA Astrophysics Data System (ADS)

Shank, T. M.

2016-02-01

From 2012 to 2015, annual seafloor surveys using the towed camera TowCam were used to characterize benthic ecosystems and habitats to groundtruth recently developed habitat suitability models that predict deep-sea coral locations in northwest Atlantic canyons. Faunal distribution, abundance, and habitat data were obtained from more than 90 towed camera surveys in 21 canyons, specifically Tom's, Hendrickson, Veatch, Gilbert, Ryan, Powell, Munson, Accomac, Leonard, Washington, Wilmington, Lindenkohl, Clipper, Sharpshooter, Welker, Dogbody, Chebacco, Heel Tapper, File Bottom, Carteret, and Spencer Canyons, as well as unnamed minor canyons and inter-canyon areas. We also investigated additional canyons including Block, Alvin, Atlantis, Welker, Heezen, Phoenix, McMaster, Nantucket, and two minor canyons and two intercanyon areas through high-definition ROV image surveys from the NOAA CANEX 2013 and 2014 expeditions. Significant differences in species composition and distribution correlated with specific habitat types, depth, and individual canyons. High abundances and diversity of scleractinians, antipatharians, octocorals and sponges were highly correlated with habitat substrates, includingvertical canyon walls, margins, sediments, cobbles, boulders, and coral rubble habitat. Significant differences in species composition among canyons were observed across similar depths suggesting that many canyons may have their own biological and geological signature. Locating and defining the composition and distribution of vulnerable coral ecosystems in canyons in concert with validating predictive species distribution modeling has resulted in the regional management and conservation recommendations of these living resources and the largest proposed Marine Protected Area in North American waters.

Geologic map and upper Paleozoic stratigraphy of the Marble Canyon area, Cottonwood Canyon quadrangle, Death Valley National Park, Inyo County, California

USGS Publications Warehouse

Stone, Paul; Stevens, Calvin H.; Belasky, Paul; Montañez, Isabel P.; Martin, Lauren G.; Wardlaw, Bruce R.; Sandberg, Charles A.; Wan, Elmira; Olson, Holly A.; Priest, Susan S.

2014-01-01

This geologic map and pamphlet focus on the stratigraphy, depositional history, and paleogeographic significance of upper Paleozoic rocks exposed in the Marble Canyon area in Death Valley National Park, California. Bedrock exposed in this area is composed of Mississippian to lower Permian (Cisuralian) marine sedimentary rocks and the Jurassic Hunter Mountain Quartz Monzonite. These units are overlain by Tertiary and Quaternary nonmarine sedimentary deposits that include a previously unrecognized tuff to which we tentatively assign an age of late middle Miocene (~12 Ma) based on tephrochronologic analysis, in addition to the previously recognized Pliocene tuff of Mesquite Spring. Mississippian and Pennsylvanian rocks in the Marble Canyon area represent deposition on the western continental shelf of North America. Mississippian limestone units in the area (Tin Mountain, Stone Canyon, and Santa Rosa Hills Limestones) accumulated on the outer part of a broad carbonate platform that extended southwest across Nevada into east-central California. Carbonate sedimentation was interrupted by a major eustatic sea-level fall that has been interpreted to record the onset of late Paleozoic glaciation in southern Gondwana. Following a brief period of Late Mississippian clastic sedimentation (Indian Springs Formation), a rise in eustatic sea level led to establishment of a new carbonate platform that covered most of the area previously occupied by the Mississippian platform. The Pennsylvanian Bird Spring Formation at Marble Canyon makes up the outer platform component of ten third-order (1 to 5 m.y. duration) stratigraphic sequences recently defined for the regional platform succession. The regional paleogeography was fundamentally changed by major tectonic activity along the continental margin beginning in middle early Permian time. As a result, the Pennsylvanian carbonate shelf at Marble Canyon subsided and was disconformably overlain by lower Permian units (Osborne Canyon and

The influence of the San Gregorio fault on the morphology of Monterey Canyon

USGS Publications Warehouse

McHugh, C.M.G.; Ryan, William B. F.; Eittreim, S.; Donald, Reed

1998-01-01

A side-scan sonar survey was conducted of Monterey Canyon and the San Gregorio fault zone, off shore of Monterey Bay. The acoustic character and morphology of the sonar images, enhanced by SeaBeam bathymetry, show the path of the San Gregorio fault zone across the shelf, upper slope, and Monterey Canyon. High backscatter linear features a few kilometers long and 100 to 200 m wide delineate the sea-floor expression of the fault zone on the shelf. Previous studies have shown that brachiopod pavements and carbonate crusts are the source of the lineations backscatter. In Monterey Canyon, the fault zone occurs where the path of the canyon makes a sharp bend from WNW to SSW (1800 m). Here, the fault is marked by NW-SE-trending, high reflectivity lineations that cross the canyon floor between 1850 m and 1900 m. The lineations can be traced to ridges on the northwestern canyon wall where they have ~ 15 m of relief. Above the low-relief ridges, bowl-shaped features have been excavated on the canyon wall contributing to the widening of the canyon. We suggest that shear along the San Gregorio fault has led to the formation of the low-relief ridges near the canyon wall and that carbonate crusts, as along the shelf, may be the source of the high backscatter features on the canyon floor. The path of the fault zone across the upper slope is marked by elongated tributary canyons with high backscatter floors and 'U'-shaped cross-sectional profiles. Linear features and stepped scarps suggestive of recent crustal movement and mass-wasting, occur on the walls and floors of these canyons. Three magnitude-4 earthquakes have occurred within the last 30 years in the vicinity of the canyons that may have contributed to the observed features. As shown by others, motion along the fault zone has juxtaposed diverse lithologies that outcrop on the canyon walls. Gully morphology and the canyon's drainage patterns have been influenced by the substrate into which the gullies have formed.

Is Canyon Width a Diagnostic Indicator of the Discharge of Megafloods on Earth and Mars?

NASA Astrophysics Data System (ADS)

Lapotre, M. G.; Lamb, M. P.

2013-12-01

On Earth, large floods have carved steep-walled and amphitheater-headed canyons from the Pleistocene (e.g. Box Canyon, ID) through the Holocene (e.g. Asbyrgi Canyon, Iceland), to historic times (e.g. Canyon Lake Gorge, TX). The geologic record on Mars suggests that similar floods have carved canyons by waterfall retreat about 3.5 billion years ago, when the red planet was wetter and possibly warmer. We currently lack robust paleo-hydraulic tools to reconstruct the discharge of ancient floods, especially on Mars where sediment sizes are obscured from observation. To address this issue, we hypothesize that the width of canyon escarpment is controlled by the hydraulics of the canyon-carving flood due to focusing of the flood into the canyon head. We compiled field data from multiple canyons and floods on Earth and Mars and show that there is a correlation between estimated flood discharge and canyon headwall width. To explore what sets this relationship, we identified five important parameters using dimensional analysis: the Froude number, the ratio of backwater length to canyon length, the ratio of backwater length to flood width, the ratio of canyon width to flood width, and the topographic slope upstream of the canyon. We used the hydraulic numerical modeling suite ANUGA to simulate overland flow over different canyon geometries and flood parameters to systematically explore the relative bed shear stresses along the canyon rim as a metric for flow focusing. Results show that canyons that exceed a certain length, scaling with the hydraulic backwater length, have shear stresses at their heads that are significantly higher than near the canyon mouth. Shear stresses along the rim of the canyon sidewalls are limited, in comparison to stresses along the canyon head, when the flood width is of the order of the backwater length. Flow focusing only occurs for subcritical flow. Together, these results suggest that canyons may only grow from a perturbation that is large

Optimizing Street Canyon Orientation for Rajarhat Newtown, Kolkata, India

NASA Astrophysics Data System (ADS)

De, Bhaskar; Mukherjee, Mahua

2017-12-01

Air temperature in urban street canyons is increased due to the morphed urban geometry, increased surface area, decreased long wave radiation and evapo-transpiration, different thermo-physical properties of surface materials and anthropogenic heat which results in thermal discomfort. Outdoor thermal stress can be mitigated substantially by properly orienting the canyons. It is crucial for the urban planners and designers to orient street canyons optimally considering variable local climatic context. It is important especially for cities in warm humid climatic context as these cities receive higher insolation with higher relative humidity and low level macro wind flow. This paper examines influence of canyon orientation on outdoor thermal comfort and proposes the optimum canyon orientation for the Rajarhat Newtown, Kolkata - a city in warm humid climate zone. Different scenarios are generated with different orientations. Change in air temperature, wind speed, Mean Radiant Temperature (MRT) and Physiological Equivalent Temperature (PET) of different scenarios are compared to find out the optimum orientation by parametric simulation in ENVI_met. Analysing the simulation results it is observed that orientation angle between 30°-60° to north performs the best for the study area of the Rajarhat Newtown. The findings of this research will be helpful for the planners to orient the street canyons optimally for future development and extension of the Rajarhat Newtown, Kolkata.

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

Giant submarine canyons: Is size any clue to their importance in the rock record?

USGS Publications Warehouse

Normark, William R.; Carlson, Paul R.

2003-01-01

Submarine canyons are the most important conduits for funneling sediment from continents to oceans. Submarine canyons, however, are zones of sediment bypassing, and little sediment accumulates in the canyon until it ceases to be an active conduit. To understand the potential importance in the rock record of any given submarine canyon, it is necessary to understand sediment-transport processes in, as well as knowledge of, deep-sea turbidite and related deposits that moved through the canyons. There is no straightforward correlation between the final volume of the sedimentary deposits and size of the associated submarine canyons. Comparison of selected modern submarine canyons together with their deposits emphasizes the wide range of scale differences between canyons and their impact on the rock record.Three of the largest submarine canyons in the world are incised into the Beringian (North American) margin of the Bering Sea. Zhemchug Canyon has the largest cross-section at the shelf break and greatest volume of incision of slope and shelf. The Bering Canyon, which is farther south in the Bering Sea, is first in length and total area. In contrast, the largest submarine fans-e.g., Bengal, Indus, and Amazon-have substantially smaller, delta-front submarine canyons that feed them; their submarine drainage areas are one-third to less than one-tenth the area of Bering Canyon. some very large deep-sea channels and tubidite deposits are not even associated with a significant submarine canyon; examples include Horizon Channel in the northeast Pacific and Laurentian Fan Valley in the North Atlantic. Available data suggest that the size of turbidity currents (as determined by volume of sediment transported to the basins) is also not a reliable indicator of submarine canyon size.

Characterization of a dam Mutant of Serratia marcescens and Nucleotide Sequence of the dam Region

PubMed Central

Ostendorf, Tammo; Cherepanov, Peter; de Vries, Johann; Wackernagel, Wilfried

1999-01-01

The DNA of Serratia marcescens has N6-adenine methylation in GATC sequences. Among 2-aminopurine-sensitive mutants isolated from S. marcescens Sr41, one was identified which lacked GATC methylation. The mutant showed up to 30-fold increased spontaneous mutability and enhanced mutability after treatment with 2-aminopurine, ethyl methanesulfonate, or UV light. The gene (dam) coding for the adenine methyltransferase (Dam enzyme) of S. marcescens was identified on a gene bank plasmid which alleviated the 2-aminopurine sensitivity and the higher mutability of a dam-13::Tn9 mutant of Escherichia coli. Nucleotide sequencing revealed that the deduced amino acid sequence of Dam (270 amino acids; molecular mass, 31.3 kDa) has 72% identity to the Dam enzyme of E. coli. The dam gene is located between flanking genes which are similar to those found to the sides of the E. coli dam gene. The results of complementation studies indicated that like Dam of E. coli and unlike Dam of Vibrio cholerae, the Dam enzyme of S. marcescens plays an important role in mutation avoidance by allowing the mismatch repair enzymes to discriminate between the parental and newly synthesized strands during correction of replication errors. PMID:10383952

Currents in monterey submarine canyon

USGS Publications Warehouse

Xu, J. P.; Noble, M.A.

2009-01-01

Flow fields of mean, subtidal, and tidal frequencies between 250 and 3300 m water depths in Monterey Submarine Canyon are examined using current measurements obtained in three yearlong field experiments. Spatial variations in flow fields are mainly controlled by the topography (shape and width) of the canyon. The mean currents flow upcanyon in the offshore reaches (>1000 m) and downcanyon in the shallow reaches (100-m amplitude isotherm oscillations and associated high-speed rectilinear currents. The 15-day spring-neap cycle and a ???3-day??? band are the two prominent frequencies in subtidal flow field. Neither of them seems directly correlated with the spring-neap cycle of the sea level.

Four-band image mosaic of the Colorado River corridor downstream of Glen Canyon Dam in Arizona, derived from the May 2013 airborne image acquisition

USGS Publications Warehouse

Durning, Laura E.; Sankey, Joel B.; Davis, Philip A.; Sankey, Temuulen T.

2016-12-14

In May 2013, the U.S. Geological Survey’s Grand Canyon Monitoring and Research Center acquired airborne multispectral high-resolution data for the Colorado River in the Grand Canyon, Arizona. The image data, which consist of four color bands (blue, green, red, and near-infrared) with a ground resolution of 20 centimeters, are available to the public as 16-bit geotiff files at http://dx.doi.org/10.5066/F7TX3CHS. The images are projected in the State Plane map projection, using the central Arizona zone (202) and the North American Datum of 1983. The assessed accuracy for these data is based on 91 ground-control points and is reported at the 95-percent confidence level as 0.64 meter (m) and a root mean square error of 0.36 m. The primary intended uses of this dataset are for maps to support field data collection and simple river navigation; high-spatial-resolution change detection of sandbars, other geomorphic landforms, riparian vegetation, and backwater and nearshore habitats; and other ecosystem-wide mapping.

Canyon formation constraints on the discharge of catastrophic outburst floods of Earth and Mars

NASA Astrophysics Data System (ADS)

Lapotre, Mathieu G. A.; Lamb, Michael P.; Williams, Rebecca M. E.

2016-07-01

Catastrophic outburst floods carved amphitheater-headed canyons on Earth and Mars, and the steep headwalls of these canyons suggest that some formed by upstream headwall propagation through waterfall erosion processes. Because topography evolves in concert with water flow during canyon erosion, we suggest that bedrock canyon morphology preserves hydraulic information about canyon-forming floods. In particular, we propose that for a canyon to form with a roughly uniform width by upstream headwall retreat, erosion must occur around the canyon head, but not along the sidewalls, such that canyon width is related to flood discharge. We develop a new theory for bedrock canyon formation by megafloods based on flow convergence of large outburst floods toward a horseshoe-shaped waterfall. The model is developed for waterfall erosion by rock toppling, a candidate erosion mechanism in well fractured rock, like columnar basalt. We apply the model to 14 terrestrial (Channeled Scablands, Washington; Snake River Plain, Idaho; and Ásbyrgi canyon, Iceland) and nine Martian (near Ares Vallis and Echus Chasma) bedrock canyons and show that predicted flood discharges are nearly 3 orders of magnitude less than previously estimated, and predicted flood durations are longer than previously estimated, from less than a day to a few months. Results also show a positive correlation between flood discharge per unit width and canyon width, which supports our hypothesis that canyon width is set in part by flood discharge. Despite lower discharges than previously estimated, the flood volumes remain large enough for individual outburst floods to have perturbed the global hydrology of Mars.

Oak Canyon Action Memo

EPA Pesticide Factsheets

This memorandum requests approval for a time-critical removal action at the 27 residential properties that compose the Oak Canyon Site located in the Village of Paguate, Pueblo of Laguna, near Cibola County, New Mexico.

Remote sensing of tamarisk beetle (Diorhabda carinulata) impacts along 412 km of the Colorado River in the Grand Canyon, Arizona, USA

USGS Publications Warehouse

Bedford, Ashton; Sankey, Temuulen T.; Sankey, Joel B.; Durning, Laura E.C.; Ralston, Barbara

2018-01-01

Tamarisk (Tamarix spp.) is an invasive plant species that is rapidly expanding along arid and semi-arid rivers in the western United States. A biocontrol agent, tamarisk beetle (Diorhabda carinulata), was released in 2001 in California, Colorado, Utah, and Texas. In 2009, the tamarisk beetle was found further south than anticipated in the Colorado River ecosystem within the Grand Canyon National Park and Glen Canyon National Recreation Area. Our objectives were to classify tamarisk stands along 412 km of the Colorado River from the Glen Canyon Dam through the Grand Canyon National Park using 2009 aerial, high spatial resolution multispectral imagery, and then quantify tamarisk beetle impacts by comparing the pre-beetle images from 2009 with 2013 post-beetle images. We classified tamarisk presence in 2009 using the Mahalanobis Distance method with a total of 2500 training samples, and assessed the classification accuracy with an independent set of 7858 samples across 49 image quads. A total of 214 ha of tamarisk were detected in 2009 along the Colorado River, where each image quad, on average, included an 8.4 km segment of the river. Tamarisk detection accuracies varied across the 49 image quads, but the combined overall accuracy across the entire study region was 74%. Using the Normalized Difference Vegetation Index (NDVI) from 2009 and 2013 with a region-specific ratio of >1.5 decline between the two image dates (2009NDVI/2013NDVI), we detected tamarisk defoliation due to beetle herbivory. The total beetle-impacted tamarisk area was 32 ha across the study region, where tamarisk defoliation ranged 1–86% at the local levels. Our tamarisk classification can aid long-term efforts to monitor the spread and impact of the beetle along the river and the eventual mortality of tamarisk due to beetle impacts. Identifying areas of tamarisk defoliation is a useful ecological indicator for managers to plan restoration and tamarisk removal efforts.

California State Waters Map Series--Hueneme Canyon and vicinity, California

USGS Publications Warehouse

Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Greene, H. Gary; Krigsman, Lisa M.; Endris, Charles A.; Clahan, Kevin B.; Sliter, Ray W.; Wong, Florence L.; Yoklavich, Mary M.; Normark, William R.

2012-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California's State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Hueneme Canyon and vicinity map area lies within the eastern Santa Barbara Channel region of the Southern California Bight. The area is part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation - at least 90° - since the early Miocene has been proposed for the Western Transverse Ranges, and the region is presently undergoing north-south shortening. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area, which is offshore of the Oxnard plain and west of and along the trend of the south flank of the Santa Monica Mountains, lies at the east end of the Santa Barbara littoral cell, characterized by west-to-east littoral transport of sediment derived mainly from coastal watersheds. The Hueneme Canyon and vicinity map area in California's State Waters is characterized by two major physiographic features: (1) the nearshore continental shelf, and (2) the Hueneme and Mugu Submarine Canyon system, which, in the map area, includes Hueneme Canyon and parts

California State Waters Map Series—Monterey Canyon and vicinity, California

USGS Publications Warehouse

Dartnell, Peter; Maier, Katherine L.; Erdey, Mercedes D.; Dieter, Bryan E.; Golden, Nadine E.; Johnson, Samuel Y.; Hartwell, Stephen R.; Cochrane, Guy R.; Ritchie, Andrew C.; Finlayson, David P.; Kvitek, Rikk G.; Sliter, Ray W.; Greene, H. Gary; Davenport, Clifton W.; Endris, Charles A.; Krigsman, Lisa M.; Dartnell, Peter; Cochran, Susan A.

2016-06-10

IntroductionIn 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath bathymetry data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow subsurface geology.The Monterey Canyon and Vicinity map area lies within Monterey Bay in central California. Monterey Bay is one of the largest embayments along the west coast of the United States, spanning 36 km from its northern to southern tips (in Santa Cruz and Monterey, respectively) and 20 km along its central axis. Not only does it contain one of the broadest sections of continental shelf along California’s coast, it also contains Monterey Canyon, one of the largest and deepest submarine canyons in the world. Note that the California’s State Waters limit extends farther offshore between Santa Cruz and Monterey so that it encompasses all of Monterey Bay.The coastal area within the map area is lightly populated. The community of Moss Landing (population, 204) hosts the largest commercial fishing fleet in Monterey Bay in its harbor. The map area also includes parts of the cities of Marina (population, about 20,000) and Castroville (population, about 6,500). Fertile lowlands of the Salinas River and Pajaro River valleys largely occupy the inland part of the map area, and land use is primarily agricultural.The offshore part of the map area lies completely within the Monterey Bay National Marine Sanctuary. The

36 CFR 7.4 - Grand Canyon National Park.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Grand Canyon National Park. 7.4 Section 7.4 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.4 Grand Canyon National Park. (a) Commercial...

36 CFR 7.4 - Grand Canyon National Park.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Grand Canyon National Park. 7.4 Section 7.4 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.4 Grand Canyon National Park. (a) Commercial...

36 CFR 7.4 - Grand Canyon National Park.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Grand Canyon National Park. 7.4 Section 7.4 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.4 Grand Canyon National Park. (a) Commercial...

36 CFR 7.4 - Grand Canyon National Park.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Grand Canyon National Park. 7.4 Section 7.4 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.4 Grand Canyon National Park. (a) Commercial...

B-Plant Canyon Ventilation Control System Description

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

MCDANIEL, K.S.

1999-08-31

Project W-059 installed a new B Plant Canyon Ventilation System. Monitoring and control of the system is implemented by the Canyon Ventilation Control System (CVCS). This document describes the CVCS system components which include a Programmable Logic Controller (PLC) coupled with an Operator Interface Unit (OIU) and application software. This document also includes an Alarm Index specifying the setpoints and technical basis for system analog and digital alarms.

Measuring currents in submarine canyons: technological and scientific progress in the past 30 years

USGS Publications Warehouse

Xu, J. P.

2011-01-01

The development and application of acoustic and optical technologies and of accurate positioning systems in the past 30 years have opened new frontiers in the submarine canyon research communities. This paper reviews several key advancements in both technology and science in the field of currents in submarine canyons since the1979 publication of Currents in Submarine Canyons and Other Sea Valleys by Francis Shepard and colleagues. Precise placements of high-resolution, high-frequency instruments have not only allowed researchers to collect new data that are essential for advancing and generalizing theories governing the canyon currents, but have also revealed new natural phenomena that challenge the understandings of the theorists and experimenters in their predictions of submarine canyon flow fields. Baroclinic motions at tidal frequencies, found to be intensified both up canyon and toward the canyon floor, dominate the flow field and control the sediment transport processes in submarine canyons. Turbidity currents are found to frequently occur in active submarine canyons such as Monterey Canyon. These turbidity currents have maximum speeds of nearly 200 cm/s, much smaller than the speeds of turbidity currents in geological time, but still very destructive. In addition to traditional Eulerian measurements, Lagrangian flow data are essential in quantifying water and sediment transport in submarine canyons. A concerted experiment with multiple monitoring stations along the canyon axis and on nearby shelves is required to characterize the storm-trigger mechanism for turbidity currents.

Modeling of flood-deposited sand distributions in a reach of the Colorado River below the Little Colorado River, Grand Canyon, Arizona

USGS Publications Warehouse

Wiele, S.M.

1998-01-01

A release from Glen Canyon Dam during March-April 1996 was designed to test the effectiveness with which the riparian environment could be renewed with discharges greatly in excess of the normal powerplant-restricted maximum. Of primary concern was the rebuilding of sand deposits along the channel sides that are important to the flora and fauna along the river corridor and that provide the only camp sites for riverside visitors to the Grand Canyon National Park. Analysis of the depositional processes with a model of flow, sand transport, and bed evolution shows that the sand deposits formed along the channel sides early during the high flow were affected only slightly by the decline in suspended-sand concentrations over the course of the controlled flood. Modeling results suggest that the removal of a large sand deposit over several hours was not a response to declining suspended-sand concentrations. Comparisons of the controlled-flood deposits with deposits formed during a flood in January 1993 on the Little Colorado River that contributed sufficient sand to raise the suspended-sand concentrations to predam levels in the main stem show that the depositional pattern as well as the magnitude is strongly influenced by the suspended-sand concentrations.

Red Rock Canyon National Conservation Area Transportation Feasibility Study

DOT National Transportation Integrated Search

2012-07-31

Red Rock Canyon National Conservation Area is a popular Bureau of Land Management natural area located near Las Vegas, Nevada. Red Rock Canyon experiences heavy congestion on its Scenic Drive and associated parking areas, due to high volumes of visit...

Formation of Ground Truth Databases and Related Studies and Regional Seismic Monitoring Research

DTIC Science & Technology

2006-06-01

denoted by black circles) and those derived by the combined use of both IRIS and revised IDC for all 70 Chinese events. Arrows point towards the...IRIS data provide a large number of additional Lg amvals. Figure 45. Differences in epicentral location between the original REB (denoted by black ...Washington, USA Haystack Fork , Wyoming, USA Hells Canyon, Colorado, USA Hiawatha Road, Colorado, USA Hockley, Texas, USA Hailey, Idaho, USA Honiara

Environmental analysis of Lower Pueblo/Lower Los Alamos Canyon, Los Alamos, New Mexico

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

Ferenbaugh, R.W.; Buhl, T.E.; Stoker, A.K.

1994-12-01

The radiological survey of the former radioactive waste treatment plant site (TA-45), Acid Canyon, Pueblo Canyon, and Los Alamos Canyon found residual contamination at the site itself and in the channel and banks of Acid, Pueblo, and lower Los Alamos Canyons all the way to the Rio Grande. The largest reservoir of residual radioactivity is in lower Pueblo Canyon, which is on DOE property. However, residual radioactivity does not exceed proposed cleanup criteria in either lower Pueblo or lower Los Alamos Canyons. The three alternatives proposed are (1) to take no action, (2) to construct a sediment trap in lowermore » Pueblo Canyon to prevent further transport of residual radioactivity onto San Ildefonso Indian Pueblo land, and (3) to clean the residual radioactivity from the canyon system. Alternative 2, to cleanup the canyon system, is rejected as a viable alternative. Thousands of truckloads of sediment would have to be removed and disposed of, and this effort is unwarranted by the low levels of contamination present. Residual radioactivity levels, under either present conditions or projected future conditions, will not result in significant radiation doses to persons exposed. Modeling efforts show that future transport activity will not result in any residual radioactivity concentrations higher than those already existing. Thus, although construction of a sediment trap in lower Pueblo Canyon is a viable alternative, this effort also is unwarranted, and the no-action alternative is the preferred alternative.« less

Fish Passage Assessment: Big Canyon Creek Watershed, Technical Report 2004.

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

Christian, Richard

2004-02-01

This report presents the results of the fish passage assessment as outlined as part of the Protect and Restore the Big Canyon Creek Watershed project as detailed in the CY2003 Statement of Work (SOW). As part of the Northwest Power Planning Council's Columbia Basin Fish and Wildlife Program (FWP), this project is one of Bonneville Power Administration's (BPA) many efforts at off-site mitigation for damage to salmon and steelhead runs, their migration, and wildlife habitat caused by the construction and operation of federal hydroelectric dams on the Columbia River and its tributaries. The proposed restoration activities within the Big Canyonmore » Creek watershed follow the watershed restoration approach mandated by the Fisheries and Watershed Program. Nez Perce Tribal Fisheries/Watershed Program vision focuses on protecting, restoring, and enhancing watersheds and treaty resources within the ceded territory of the Nez Perce Tribe under the Treaty of 1855 with the United States Federal Government. The program uses a holistic approach, which encompasses entire watersheds, ridge top to ridge top, emphasizing all cultural aspects. We strive toward maximizing historic ecosystem productive health, for the restoration of anadromous and resident fish populations. The Nez Perce Tribal Fisheries/Watershed Program (NPTFWP) sponsors the Protect and Restore the Big Canyon Creek Watershed project. The NPTFWP has the authority to allocate funds under the provisions set forth in their contract with BPA. In the state of Idaho vast numbers of relatively small obstructions, such as road culverts, block thousands of miles of habitat suitable for a variety of fish species. To date, most agencies and land managers have not had sufficient, quantifiable data to adequately address these barrier sites. The ultimate objective of this comprehensive inventory and assessment was to identify all barrier crossings within the watershed. The barriers were then prioritized according to the amount

Morphology of Submarine Canyons in the Palomares Margin (East of Alboran Sea, western Mediterranean)

NASA Astrophysics Data System (ADS)

Perez-Hernandez, S.; Comas, M. C.; Escutia, C.

2009-04-01

Morphological analysis on the Palomares Margin has been done using high-resolution swath bathymetry data collected during the MARSIBAL-06 (2006) cruise on board of the R/V BIO Hespérides. Complemented with data from GEBCO 2000 and Ifremer (Medimap Group, 2007) the data-set provides the first complete bathymetric mosaic of the Palomares Margin. The bathymetric mosaic allows to study the physiographic provinces of the Palomares Margin and to conduct, for the first time, a detailed morphological analysis of the two main sediment-transfer conduits: the Gata and the Alias-Almanzora Canyons. The Gata Canyon extends for 64km from the outer shelf to the base of the slope with a general W-E direction. A tributary system of canyons originates at the shelf break and continues on the slope until they merge at 1230m water depth. The walls of the canyons are characterized by repeated slides. Perpendicular profiles to the Canyon pathway reveal gentle transversal "V" asymmetrical shapes with a marked axial incision on the canyon floor (highs between 65 to 103m in the southern flank, and between 30-90m in the northern flank ). The transition from an erosional canyon to a deposition channel is located at 2100m water depth, and is characterized by trapezoidal shapes on transversal profiles accompanied of lower relieves (40-65m). At the mouth of the canyon-channel system no sedimentary lobes are observed. The Alias-Almanzora canyon (73km long and preferential direction W-E) is located North of the Gata Canyon and extends from the continental shelf to the base of the slope. A tributary system to the Alias- Almanzora canyon-head locates less than 150m from the coast, facing a fluvial drainage system onland. Proximal tributary canyons and gullies feed the main canyon until it merges in the continental slope at 1516m water depth. The tributary system exhibits a marked "V" shape in transverse profiles and marked axial incisions. Down slope, transversal profiles have trapezoidal shapes

Hoover Dam Learning Packet.

ERIC Educational Resources Information Center

Bureau of Reclamation (Dept. of Interior), Washington, DC.

This learning packet provides background information about Hoover Dam (Nevada) and the surrounding area. Since the dam was built at the height of the Depression in 1931, people came from all over the country to work on it. Because of Hoover Dam, the Colorado River was controlled for the first time in history and farmers in Nevada, California, and…

Does littoral sand bypass the head of Mugu Submarine Canyon? - a modeling study

USGS Publications Warehouse

Xu, Jingping; Elias, Edwin; Kinsman, Nicole; Wang, Ping; Rosati, Julie D.; Roberts, Tiffany M.

2011-01-01

A newly developed sand-tracer code for the process-based model Delft3D (Deltares, The Netherlands) was used to simulate the littoral transport near the head of the Mugu Submarine Canyon in California, USA. For westerly swells, which account for more than 90% of the wave conditions in the region, the sand tracers in the downcoast littoral drift were unable to bypass the canyon head. A flow convergence near the upcoast rim of the canyon intercepts the tracers and moves them either offshore onto the shelf just west of the canyon rim (low wave height conditions) or into the canyon head (storm wave conditions). This finding supports the notion that Mugu Canyon is the true terminus of the Santa Barbara Littoral Cell.

Influence of San Gabriel submarine canyon on narrow-shelf sediment dynamics, southern California

USGS Publications Warehouse

Karl, Herman A.

1980-01-01

A conceptual model attributes the PTC to modification of shelf circulation patterns by San Gabriel Canyon. Surface waves diverge over the canyon head resulting in differential wave set up at the shore face. This forces back turbid nearshore water for a distance of a few kilometers toward the canyon. At some point on the shelf, seaward nearshore flow overlaps offshore currents generated or modified by internal waves focused onto the shelf by the canyon and/or turbulent eddies produced by flow separation in currents moving across the canyon axis. At times, these subtle processes overprint tidal and wind-driven currents and thereby create the PTC. The model suggests that canyons heading several kilometers from shore can have a regulatory effect on narrow-shelf sediment dynamics.

Geomorphic characterization of four shelf-sourced submarine canyons along the U.S. Mid-Atlantic continental margin

USGS Publications Warehouse

Obelcz, Jeffrey; Brothers, Daniel S.; Chaytor, Jason D.; ten Brink, Uri S.; Ross, Steve W.; Brooke, Sandra

2013-01-01

Shelf-sourced submarine canyons are common features of continental margins and are fundamental to deep-sea sedimentary systems. Despite their geomorphic and geologic significance, relatively few passive margin shelf-breaching canyons worldwide have been mapped using modern geophysical methods. Between 2007 and 2012 a series of geophysical surveys was conducted across four major canyons of the US Mid-Atlantic margin: Wilmington, Baltimore, Washington, and Norfolk canyons. More than 5700 km2 of high-resolution multibeam bathymetry and 890 line-km of sub-bottom CHIRP profiles were collected along the outer shelf and uppermost slope (depths of 80-1200 m). The data allowed us to compare and contrast the fine-scale morphology of each canyon system. The canyons have marked differences in the morphology and orientation of canyon heads, steepness and density of sidewall gullies, and the character of the continental shelf surrounding canyon rims. Down-canyon axial profiles for Washington, Baltimore and Wilmington canyons have linear shapes, and each canyon thalweg exhibits morphological evidence for recent, relatively small-scale sediment transport. For example, Washington Canyon displays extremely steep wall gradients and contains ~100 m wide, 5–10 m deep, v-shaped incisions down the canyon axis, suggesting modern or recent sediment transport. In contrast, the convex axial thalweg profile, the absence of thalweg incision, and evidence for sediment infilling at the canyon head, suggest that depositional processes strongly influence Norfolk Canyon during the current sea-level high-stand. The north walls of Wilmington, Washington and Norfolk canyons are steeper than the south walls due to differential erosion, though the underlying cause for this asymmetry is not clear. Furthermore, we speculate that most of the geomorphic features observed within the canyons (e.g., terraces, tributary canyons, gullies, and hanging valleys) were formed during the Pleistocene, and show only

Composition, Distribution and Abundance of Anthropogenic Marine Debris in Northwest Atlantic Submarine Canyons

NASA Astrophysics Data System (ADS)

Heyl, T. P.; Nizinski, M. S.; Kinlan, B. P.; Shank, T. M.

2016-02-01

Submarine canyons are important productive habitats in the deep-sea, as well as downslope conduits for transporting sediment and organic material that enhances local and regional species diversity, including species and ecosystems vulnerable to anthropogenic activities. In 2012 and 2013, we documented and characterized deep-sea coral and sponge ecosystems in virtually unexplored northeast and mid-Atlantic canyons using WHOI's TowCam towed imaging system on the FSV Bigelow. Specifically, thirty-eight digital image TowCam surveys were completed in 10 canyons, with more than 91,000 images documenting not only deep-sea coral and sponge ecosystems and habitat features, but also anthropogenic debris. Canyons surveyed cover most of the latitudinal range of the northeast US region and include Toms Canyon complex, Ryan, Veatch, Gilbert, Powell, and Munson canyons. Each of these canyon hosted debris across depths of 550 to 2100m, consisting mostly of fisheries equipment, including fishing lines, traps, and nets. Potentially-land-based debris (e.g., plastic bags and magazines) was also present in all canyons surveyed. These substrates likely enhance colonization and often served as habitat for specific sessile and mobile species. Comparisons of debris in these canyons revealed depth-related differences, likely due to offshore extent of fishing activities, and will be compared to density and abundances of other deep-sea environments. The occurrence of anthropogenic debris on Northeast US canyon floors suggests major sources via transport ship and fishing-related activities and perhaps the rapid transport of debris through near-shore zones and entrainment in bottom currents.

Dynamic decision making for dam-break emergency management - Part 2: Application to Tangjiashan landslide dam failure

NASA Astrophysics Data System (ADS)

Peng, M.; Zhang, L. M.

2013-02-01

Tangjiashan landslide dam, which was triggered by the Ms = 8.0 Wenchuan earthquake in 2008 in China, threatened 1.2 million people downstream of the dam. All people in Beichuan Town 3.5 km downstream of the dam and 197 thousand people in Mianyang City 85 km downstream of the dam were evacuated 10 days before the breaching of the dam. Making such an important decision under uncertainty was difficult. This paper applied a dynamic decision-making framework for dam-break emergency management (DYDEM) to help rational decision in the emergency management of the Tangjiashan landslide dam. Three stages are identified with different levels of hydrological, geological and social-economic information along the timeline of the landslide dam failure event. The probability of dam failure is taken as a time series. The dam breaching parameters are predicted with a set of empirical models in stage 1 when no soil property information is known, and a physical model in stages 2 and 3 when knowledge of soil properties has been obtained. The flood routing downstream of the dam in these three stages is analyzed to evaluate the population at risk (PAR). The flood consequences, including evacuation costs, flood damage and monetized loss of life, are evaluated as functions of warning time using a human risk analysis model based on Bayesian networks. Finally, dynamic decision analysis is conducted to find the optimal time to evacuate the population at risk with minimum total loss in each of these three stages.

10. EASTERLY VIEW OF THE ACCESS ROAD TO THE DOWNSTREAM ...

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

10. EASTERLY VIEW OF THE ACCESS ROAD TO THE DOWNSTREAM SIDE OF BIG DALTON DAM EXTENDING FROM THE FOOTBRIDGE TO THE GAGING STATION. BIG DALTON DAM IN BACKGROUND. - Big Dalton Dam, 2600 Big Dalton Canyon Road, Glendora, Los Angeles County, CA

The geomorphic influences of beaver dams and failures of beaver dams

NASA Astrophysics Data System (ADS)

Butler, David R.; Malanson, George P.

2005-10-01

Uncounted millions of beaver ponds and dams existed in North America prior to European contact and colonization. These ponds acted as sediment traps that contained tens to hundreds of billions of cubic meters of sediment that would otherwise have passed through the fluvial system. Removal of beavers by overtrapping in the 16th-19th centuries severely reduced their number and the number of ponds and dams. Dam removal altered the fluvial landscape of North America, inducing sediment evacuation and entrenchment in concert with widespread reduction in the wetlands environments. Partial recovery of beaver populations in the 20th century has allowed reoccupation of the entirety of the pre-contact range, but at densities of only one-tenth the numbers. Nevertheless, modern beaver ponds also trap large volumes of sediment in the high hundred millions to low billions of cubic meters range. Failure of beaver dams is a more common phenomenon than often assumed in the literature. During the past 20 years, numerous cases of dam failure have been documented that resulted in outburst floods. These floods have been responsible for 13 deaths and numerous injuries, including significant impacts on railway lines.

Creationism in the Grand Canyon, Texas Textbooks

NASA Astrophysics Data System (ADS)

Folger, Peter

2004-01-01

AGU President Bob Dickinson, together with presidents of six other scientific societies, have written to Joseph Alston, Superintendent of Grand Canyon National Park, pointing out that a creationist book, The Grand Canyon: A Different View, is being sold in bookstores within the borders of the park as a scientific explanation about Grand Canyon geologic history. President Dickinson's 16 December letter urges that Alston clearly separate The Grand Canyon: A Different View from books and materials that discuss the legitimate scientific understanding of the origin of the Grand Canyon. The letter warns the Park Service against giving the impression that it approves of the anti-science movement known as young-Earth creationism, or that it endorses the advancement of religious tenets disguised as science. The text of the letter is on AGU's Web site http://www.agu.org/sci_soc/policy/sci_pol.html. Also, this fall, AGU sent an alert to Texas members about efforts by intelligent design creationists aimed at weakening the teaching of biological evolution in textbooks used in Texas schools. The alert pointed scientists to a letter, drafted by AGU, together with the American Institute of Physics, the American Physical Society, the Optical Society of America, and the American Astronomical Society, that urged the Texas State Board of Education to adopt textbooks that presented only accepted, peer-reviewed science and pedagogical expertise. Over 550 scientists in Texas added their names to the letter (http://www.agu.org/sci_soc/policy/texas_textbooks.pdf ), sent to the Board of Education on 1 November prior to their vote to adopt a slate of new science textbooks. The Board voted 11-5 in favor of keeping the textbooks free of changes advocated by groups supporting intelligent design creationism.

Anomalous topography on the continental shelf around Hudson Canyon

USGS Publications Warehouse

Knebel, H.J.

1979-01-01

Recent seismic-reflection data show that the topography on the Continental Shelf around Hudson Canyon is composed of a series of depressions having variable spacings (< 100 m to 2 km), depths (1-10 m), outlines, and bottom configurations that give the sea floor an anomalous "jagged" appearance in profile. The acoustic and sedimentary characteristics, the proximity to relict shores, and the areal distribution indicate that this rough topography is an erosional surface formed on Upper Pleistocene silty sands about 13,000 to 15,000 years ago by processes related to Hudson Canyon. The pronounced southward extension of the surface, in particular, may reflect a former increase in the longshore-current erosion capacity caused by the loss of sediments over the canyon. Modern erosion or nondeposition of sediments has prevented the ubiquitous sand sheet on the Middle Atlantic shelf from covering the surface. The "anomalous" topography may, in fact, be characteristic of areas near other submarine canyons that interrupt or have interrupted the longshore drift of sediments. ?? 1979.

Travel times, streamflow velocities, and dispersion rates in the Missouri River upstream from Canyon Ferry Lake, Montana

USGS Publications Warehouse

Whiteman, Aroscott

2012-01-01

In 2010, the U.S. Geological Survey, in cooperation with the Montana Department of Environmental Quality, initiated a dye-tracer study to determine travel times, streamflow velocities, and longitudinal dispersion rates for the Missouri River upstream from Canyon Ferry Lake. For this study, rhodamine WT (RWT) dye was injected at two locations, Missouri River Headwaters State Park in early September and Broadwater-Missouri Dam (Broadwater Dam) in late August 2010. Dye concentrations were measured at three sites downstream from each dye-injection location. The study area was a 41.2-mile reach of the Missouri River from Trident, Montana, at the confluence of the Jefferson, Madison, and Gallatin Rivers (Missouri River Headwaters) at river mile 2,319.40 downstream to the U.S. Route 12 Bridge (Townsend Bridge), river mile 2,278.23, near Townsend, Montana. Streamflows were reasonably steady and ranged from 3,070 to 3,700 cubic feet per second. Mean velocities were calculated for each subreach between measurement sites for the leading edge, peak concentration, centroid, and trailing edge at 10 percent of the peak concentration of the dye plume. Calculated velocities for the centroid of the dye plume ranged from 0.80 to 3.02 feet per second within the study reach from Missouri River Headwaters to Townsend Bridge, near Townsend. The mean velocity of the dye plume for the entire study reach, excluding the subreach between the abandoned Milwaukee Railroad bridge at Lombard, Montana (Milwaukee Bridge) and Broadwater-Missouri Dam (Broadwater Dam), was 2.87 feet per second. The velocity of the centroid of the dye plume for the subreach between Milwaukee Bridge and Broadwater Dam (Toston Reservoir) was 0.80 feet per second. The residence time for Toston Reservoir was 8.2 hours during this study. Estimated longitudinal dispersion rates of the dye plume for this study ranged from 0.72 feet per second for the subreach from Milwaukee Bridge to Broadwater Dam to 2.26 feet per second for

9. SOUTHERLY VIEW OF THE ACCESS ROAD TO THE DOWNSTREAM ...

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

9. SOUTHERLY VIEW OF THE ACCESS ROAD TO THE DOWNSTREAM SIDE OF BIG DALTON DAM EXTENDING FROM THE DAM TO THE FOOTBRIDGE. VIEW FROM BIG DALTON DAM SHOWING THE TOE WEIR IN FOREGROUND AND FOOTBRIDGE IN BACKGROUND. - Big Dalton Dam, 2600 Big Dalton Canyon Road, Glendora, Los Angeles County, CA

The timing of sediment transport down Monterey Submarine Canyon, offshore California

USGS Publications Warehouse

Stevens, Thomas; Paull, Charles K.; Ussler, William III; McGann, Mary; Buylaert, Jan-Pieter; Lundsten, Eve M.

2013-01-01

While submarine canyons are the major conduits through which sediments are transported from the continents out into the deep sea, the time it takes for sediment to pass down through a submarine canyon system is poorly constrained. Here we report on the first study to couple optically stimulated luminescence (OSL) ages of quartz sand deposits and accelerator mass spectrometry 14C ages measured on benthic foraminifera to examine the timing of sediment transport through the axial channel of Monterey Submarine Canyon and Fan, offshore California. The OSL ages date the timing of sediment entry into the canyon head while the 14C ages of benthic foraminifera record the deposition of hemipelagic sediments that bound the sand horizons. We use both single-grain and small (∼2 mm area) single-aliquot regeneration approaches on vibracore samples from fining-upward sequences at various water depths to demonstrate relatively rapid, decadal-scale sand transport to at least 1.1 km depth and more variable decadal- to millennial-scale transport to a least 3.5 km depth on the fan. Significant differences between the time sand was last exposed at the canyon head (OSL age) and the timing of deposition of the sand (from 14C ages of benthic foraminifera in bracketing hemipelagic sediments) are interpreted as indicating that the sand does not pass through the entire canyon instantly in large individual events, but rather moves multiple times before emerging onto the fan. The increased spread in single-grain OSL dates with water depth provides evidence of mixing and temporary storage of sediment as it moves through the canyon system. The ages also indicate that the frequency of sediment transport events decreases with distance down the canyon channel system. The amalgamated sands near the canyon head yield OSL ages that are consistent with a sub-decadal recurrence frequency while the fining-upward sand sequences on the fan indicate that the channel is still experiencing events with a 150�

5. Long view from canyon edge, west of the overlook, ...

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

5. Long view from canyon edge, west of the overlook, showing relationship of Mather Point to neighboring south rim projections; view to southeast - Mather Point Overlook, South Entrance Road, Grand Canyon Village, Coconino County, AZ

Divergent Effects of Beliefs in Heaven and Hell on National Crime Rates

PubMed Central

Shariff, Azim F.; Rhemtulla, Mijke

2012-01-01

Though religion has been shown to have generally positive effects on normative ‘prosocial’ behavior, recent laboratory research suggests that these effects may be driven primarily by supernatural punishment. Supernatural benevolence, on the other hand, may actually be associated with less prosocial behavior. Here, we investigate these effects at the societal level, showing that the proportion of people who believe in hell negatively predicts national crime rates whereas belief in heaven predicts higher crime rates. These effects remain after accounting for a host of covariates, and ultimately prove stronger predictors of national crime rates than economic variables such as GDP and income inequality. Expanding on laboratory research on religious prosociality, this is the first study to tie religious beliefs to large-scale cross-national trends in pro- and anti-social behavior. PMID:22723927

Hydraulics of outburst floods spilling over a steep-walled canyon: Implications for paleo-discharges on Mars

NASA Astrophysics Data System (ADS)

Lapotre, Mathieu; Lamb, Michael

2013-04-01

Canyons carved by outburst floods are common landforms on Earth and Mars. These canyons are generally found in fractured basalts and jointed sedimentary rocks. Flood-carved canyons commonly have steep headwalls and a roughly constant width, and are often thought to have formed from upstream headwall propagation due to waterfall erosion. Because morphology is readily available from satellite imagery, these canyons offer a unique opportunity to quantify the discharge of rare, catastrophic paleo-floods on Earth and Mars. However, mechanistic relationships that relate canyon size to flood discharge have yet to be developed. We propose that the width of a canyon headwall in fractured rock is set by the spatial distribution of erosion around the rim of the canyon, which is controlled by the distribution of shear stresses induced by the overflowing water as it is focused into the canyon head. We test this hypothesis by performing a series of numerical simulations of flood-water focusing using ANUGA Hydro, a 2D-depth averaged, fully turbulent, hydraulic numerical modeling suite allowing for Froude-number transitions. The numerical simulations were designed to explore five dimensionless variables: the aspect ratio of the canyon (length normalized by width), the canyon width to flood-water width ratio, the canyon width to normal-flow depth ratio, the Froude number, and the topographic gradient upstream of the canyon. Preliminary results show that flow focusing leads to increased shear stresses at the canyon head compared to the sides of the canyon for subcritical floods and higher canyon aspect ratios. This suggests that proto-canyons start growing from a topographic defect in all directions until they reach a critical length for the side walls to dry. Once this critical length is attained, canyons focus most of the flood waters into their heads, and propagate upstream only, maintaining roughly constant widths. Preliminary results suggest that canyon width may be used to

Dam nation: A geographic census of American dams and their large-scale hydrologic impacts

NASA Astrophysics Data System (ADS)

Graf, William L.

1999-04-01

Newly available data indicate that dams fragment the fluvial system of the continental United States and that their impact on river discharge is several times greater than impacts deemed likely as a result of global climate change. The 75,000 dams in the continental United States are capable of storing a volume of water almost equaling one year's mean runoff, but there is considerable geographic variation in potential surface water impacts. In some western mountain and plains regions, dams can store more than 3 year's runoff, while in the Northeast and Northwest, storage is as little as 25% of the annual runoff. Dams partition watersheds; the drainage area per dam varies from 44 km2 (17 miles2) per dam in New England to 811 km2 (313 miles2) per dam in the Lower Colorado basin. Storage volumes, indicators of general hydrologic effects of dams, range from 26,200 m3 km-2 (55 acre-feet mile-2) in the Great Basin to 345,000 m3 km-2 (725 acre-feet mile-2) in the South Atlantic region. The greatest river flow impacts occur in the Great Plains, Rocky Mountains, and the arid Southwest, where storage is up to 3.8 times the mean annual runoff. The nation's dams store 5000 m3 (4 acre-feet) of water per person. Water resource regions have experienced individualized histories of cumulative increases in reservoir storage (and thus of downstream hydrologic and ecologic impacts), but the most rapid increases in storage occurred between the late 1950s and the late 1970s. Since 1980, increases in storage have been relatively minor.

Partly standing internal tides in a dendritic submarine canyon observed by an ocean glider

NASA Astrophysics Data System (ADS)

Hall, Rob A.; Aslam, Tahmeena; Huvenne, Veerle A. I.

2017-08-01

An autonomous ocean glider is used to make the first direct measurements of internal tides within Whittard Canyon, a large, dendritic submarine canyon system that incises the Celtic Sea continental slope and a site of high benthic biodiversity. This is the first time a glider has been used for targeted observations of internal tides in a submarine canyon. Vertical isopycnal displacement observations at different stations fit a one-dimensional model of partly standing semidiurnal internal tides - comprised of a major, incident wave propagating up the canyon limbs and a minor wave reflected back down-canyon by steep, supercritical bathymetry near the canyon heads. The up-canyon internal tide energy flux in the primary study limb decreases from 9.2 to 2.0 kW m-1 over 28 km (a dissipation rate of 1 - 2.5 ×10-7 Wkg-1), comparable to elevated energy fluxes and internal tide driven mixing measured in other canyon systems. Within Whittard Canyon, enhanced mixing is inferred from collapsed temperature-salinity curves and weakened dissolved oxygen concentration gradients near the canyon heads. It has previously been hypothesised that internal tides impact benthic fauna through elevated near-bottom current velocities and particle resuspension. In support of this, we infer order 20 cm s-1 near-bottom current velocities in the canyon and observe high concentrations of suspended particulate matter. The glider observations are also used to estimate a 1 °C temperature range and 12 μmol kg-1 dissolved oxygen concentration range, experienced twice a day by organisms on the canyon walls, due to the presence of internal tides. This study highlights how a well-designed glider mission, incorporating a series of tide-resolving stations at key locations, can be used to understand internal tide dynamics in a region of complex topography, a sampling strategy that is applicable to continental shelves and slopes worldwide.

Interview: Professor Helle Neergaard, President of the European Council for Small Business and Entrepreneurship, on the Nature of Creativity, Innovation and Entrepreneurship

ERIC Educational Resources Information Center

Industry and Higher Education, 2015

2015-01-01

On August 13, 2014, Rita G. Klapper conducted a Skype interview with Helle Neergaard. Neergaard is not only President of the European Council for Small Business and Entrepreneurship, but also Docent at the Hanken School of Economics, and Professor at iCARE, Department of Business Administration, School of Business and Social Sciences, University…

Space-for-time substitution and the evolution of submarine canyons in a passive, progradational margin.

NASA Astrophysics Data System (ADS)

Micallef, Aaron; Ribó, Marta; Canals, Miquel; Puig, Pere; Lastras, Galderic; Tubau, Xavier

2013-04-01

40% of submarine canyons worldwide are located in passive margins, where they constitute preferential conduits of sediment and biodiversity hotspots. Recent studies have presented evidence that submarine canyons incising passive, progradational margins can co-evolve with the adjacent continental slope during long-term margin construction. The stages of submarine canyon initiation and their development into a mature canyon-channel system are still poorly constrained, however, which is problematic when attempting to reconstruct the development of passive continental margins. In this study we analyse multibeam echosounder and seismic reflection data from the southern Ebro margin (western Mediterranean Sea) to document the stages through which a first-order gully develops into a mature, shelf-breaching canyon and, finally, into a canyon-channel system. This morphological evolution allows the application of a space-for-time substitution approach. Initial gully growth on the continental slope takes place via incision and downslope elongation, with limited upslope head retreat. Gravity flows are the main driver of canyon evolution, whereas slope failures are the main agent of erosion; they control the extent of valley widening, promote tributary development, and their influence becomes more significant with time. Breaching of the continental shelf by a canyon results in higher water/sediment loads that enhance canyon development, particularly in the upper reaches. Connection of the canyon head with a paleo-river changes evolution dynamics significantly, promoting development of a channel and formation of depositional landforms. Morphometric analyses demonstrate that canyons develop into geometrically self-similar systems that approach steady-state and higher drainage efficiency. Canyon activity in the southern Ebro margin is pulsating and enhanced during sea level lowstands. Rapid sedimentation by extension of the palaeo-Millars River into the outermost shelf and upper

Taxonomic and compositional differences of ground-dwelling arthropods in riparian habitats in Glen Canyon, Arizona, USA

USGS Publications Warehouse

Ralston, Barbara; Cobb, Neil S.; Brantley, Sandra L.; Higgins, Jacob; Yackulic, Charles B.

2017-01-01

The disturbance history, plant species composition, productivity, and structural complexity of a site can exert bottom-up controls on arthropod diversity, abundance, and trophic structure. Regulation alters the hydrology and disturbance regimes of rivers and affects riparian habitats by changing plant quality parameters. Fifty years of regulation along the Colorado River downstream of Glen Canyon Dam has created a no-analog, postdam “lower” riparian zone close to the water's edge that includes tamarisk (Tamarix sp.), a nonnative riparian shrub. At the same time, the predam “upper” facultative riparian zone has persisted several meters above the current flood stage. In summer 2009, we used pitfall traps within these 2 riparian zones that differ in plant composition, productivity, and disturbance frequency to test for differences in arthropod community (Hymenoptera, Arachnida, and Coleoptera) structure. Arthropod community structure differed substantially between the 2 zones. Arthropod abundance and species richness was highest in the predam upper riparian zone, even though there was a greater amount of standing plant biomass in the postdam lower riparian zone. Omnivore abundance was proportionately greater in the upper riparian zone and was associated with lower estimated productivity values. Predators and detritivores were proportionately greater in the postdam lower riparian zone. In this case, river regulation may create habitats that support species of spiders and carabid beetles, but few other species that are exclusive to this zone. The combined richness found in both zones suggests a small increase in total richness and functional diversity for the Glen Canyon reach of the Colorado River.

Regional economic impacts of Grand Canyon river runners.

PubMed

Hjerpe, Evan E; Kim, Yeon-Su

2007-10-01

Economic impact analysis (EIA) of outdoor recreation can provide critical social information concerning the utilization of natural resources. Outdoor recreation and other non-consumptive uses of resources are viewed as environmentally friendly alternatives to extractive-type industries. While outdoor recreation can be an appropriate use of resources, it generates both beneficial and adverse socioeconomic impacts on rural communities. The authors used EIA to assess the regional economic impacts of rafting in Grand Canyon National Park. The Grand Canyon region of northern Arizona represents a rural US economy that is highly dependent upon tourism and recreational expenditures. The purpose of this research is twofold. The first is to ascertain the previously unknown regional economic impacts of Grand Canyon river runners. The second purpose is to examine attributes of these economic impacts in terms of regional multipliers, leakage, and types of employment created. Most of the literature on economic impacts of outdoor recreation has focused strictly on the positive economic impacts, failing to illuminate the coinciding adverse and constraining economic impacts. Examining the attributes of economic impacts can highlight deficiencies and constraints that limit the economic benefits of recreation and tourism. Regional expenditure information was obtained by surveying non-commercial boaters and commercial outfitters. The authors used IMPLAN input-output modeling to assess direct, indirect, and induced effects of Grand Canyon river runners. Multipliers were calculated for output, employment, and income. Over 22,000 people rafted on the Colorado River through Grand Canyon National Park in 2001, resulting in an estimated $21,100,000 of regional expenditures to the greater Grand Canyon economy. However, over 50% of all rafting-related expenditures were not captured by the regional economy and many of the jobs created by the rafting industry are lower-wage and seasonal. Policy

Experimental research on the dam-break mechanisms of the Jiadanwan landslide dam triggered by the Wenchuan earthquake in China.

PubMed

Xu, Fu-gang; Yang, Xing-guo; Zhou, Jia-wen; Hao, Ming-hui

2013-01-01

Dam breaks of landslide dams are always accompanied by large numbers of casualties, a large loss of property, and negative influences on the downstream ecology and environment. This study uses the Jiadanwan landslide dam, created by the Wenchuan earthquake, as a case study example. Several laboratory experiments are carried out to analyse the dam-break mechanism of the landslide dam. The different factors that impact the dam-break process include upstream flow, the boulder effect, dam size, and channel discharge. The development of the discharge channel and the failure of the landslide dam are monitored by digital video and still cameras. Experimental results show that the upstream inflow and the dam size are the main factors that impact the dam-break process. An excavated discharge channel, especially a trapezoidal discharge channel, has a positive effect on reducing peak flow. The depth of the discharge channel also has a significant impact on the dam-break process. The experimental results are significant for landslide dam management and flood disaster prevention and mitigation.

Experimental Research on the Dam-Break Mechanisms of the Jiadanwan Landslide Dam Triggered by the Wenchuan Earthquake in China

PubMed Central

Xu, Fu-gang; Yang, Xing-guo; Hao, Ming-hui

2013-01-01

Dam breaks of landslide dams are always accompanied by large numbers of casualties, a large loss of property, and negative influences on the downstream ecology and environment. This study uses the Jiadanwan landslide dam, created by the Wenchuan earthquake, as a case study example. Several laboratory experiments are carried out to analyse the dam-break mechanism of the landslide dam. The different factors that impact the dam-break process include upstream flow, the boulder effect, dam size, and channel discharge. The development of the discharge channel and the failure of the landslide dam are monitored by digital video and still cameras. Experimental results show that the upstream inflow and the dam size are the main factors that impact the dam-break process. An excavated discharge channel, especially a trapezoidal discharge channel, has a positive effect on reducing peak flow. The depth of the discharge channel also has a significant impact on the dam-break process. The experimental results are significant for landslide dam management and flood disaster prevention and mitigation. PMID:23844387

The Jurassic section along McElmo Canyon in southwestern Colorado

USGS Publications Warehouse

O'Sullivan, Robert B.

1997-01-01

In McElmo Canyon, Jurassic rocks are 1500-1600 ft thick. Lower Jurassic rocks of the Glen Canyon Group include (in ascending order) Wingate Sandstone, Kayenta Formation and Navajo Sandstone. Middle Jurassic rocks are represented by the San Rafael Group, which includes the Entrada Sandstone and overlying Wanakah Formation. Upper Jurassic rocks comprise the Junction Creek Sandstone overlain by the Morrison Formation. The Burro Canyon Formation, generally considered to be Lower Cretaceous, may be Late Jurassic in the McElmo Canyon area and is discussed with the Jurassic. The Upper Triassic Chinle Formation in the subsurface underlies, and the Upper Cretaceous Dakota Sandstone overlies, the Jurassic section. An unconformity is present at the base of the Glen Canyon Group (J-0), at the base of the San Rafael Group (J-2), and at the base of the Junction Creek Sandstone (J-5). Another unconformity of Cretaceous age is at the base of the Dakota Sandstone. Most of the Jurassic rocks consist of fluviatile, lacustrine and eolian deposits. The basal part of the Entrada Sandstone and the Wanakah Formation may be of marginal marine origin.

Event-driven sediment flux in Hueneme and Mugu submarine canyons, southern California

USGS Publications Warehouse

Xu, J. P.; Swarzenski, P.W.; Noble, M.; Li, A.-C.

2010-01-01

Vertical sediment fluxes and their dominant controlling processes in Hueneme and Mugu submarine canyons off south-central California were assessed using data from sediment traps and current meters on two moorings that were deployed for 6 months during the winter of 2007. The maxima of total particulate flux, which reached as high as 300+ g/m2/day in Hueneme Canyon, were recorded during winter storm events when high waves and river floods often coincided. During these winter storms, wave-induced resuspension of shelf sediment was a major source for the elevated sediment fluxes. Canyon rim morphology, rather than physical proximity to an adjacent river mouth, appeared to control the magnitude of sediment fluxes in these two submarine canyon systems. Episodic turbidity currents and internal bores enhanced sediment fluxes, particularly in the lower sediment traps positioned 30 m above the canyon floor. Lower excess 210Pb activities measured in the sediment samples collected during periods of peak total particulate flux further substantiate that reworked shelf-, rather than newly introduced river-borne, sediments supply most of the material entering these canyons during storms.

The Effects of Dams on Downstream Channel Characteristics in Pennsylvania and Maryland: Assessing the Potential Consequences of Dam Removal

NASA Astrophysics Data System (ADS)

Skalak, K. J.; Pizzuto, J. E.; Jenkins, P.

2003-12-01

The potential downstream effects of dam removal were assessed on fifteen sites of varying dam size and characteristics in Pennsylvania and Maryland. The dams ranged in size from a 30 cm high fish weir to a water supply dam 57 m high. Stream order ranged from 1 to 4. The dams are located in watersheds with varying degrees of human disturbance and urbanization. The dams are also operated differently, with significant consequences for hydraulic residence time and downstream flow variability. Most streams were alluvial, but 6 of the reaches were clearly bedrock channels. We hypothesize that the channel upstream, which is unaffected by the dam, will provide an accurate model for the channel downstream of the dam long after dam removal. Therefore, reaches upstream and downstream of the dam were compared to determine the effects of the dam as well as the condition of the stream that will ultimately develop decades after dam removal. Surprisingly, the dams had no consistent influence on channel morphology. However, the percentage of sand is significantly lower downstream than upstream: the mean % sand downstream is 11.47%, while the mean % sand upstream is 21.39%. The coarser fractions of the bed, as represented by the 84th percentile grain diameter, are unaffected by the presence of the dam. These results imply that decades after dam removal, the percentage of sand on the bed will increase, but the coarse fraction of the bed will remain relatively unchanged.

36 CFR 7.70 - Glen Canyon National Recreation Area.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Glen Canyon National Recreation Area. 7.70 Section 7.70 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... in excess of flat wake speed on the Escalante River from Cow Canyon to Coyote Creek. (3) After...

36 CFR 7.70 - Glen Canyon National Recreation Area.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Glen Canyon National Recreation Area. 7.70 Section 7.70 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... in excess of flat wake speed on the Escalante River from Cow Canyon to Coyote Creek. (3) After...

36 CFR 7.70 - Glen Canyon National Recreation Area.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Glen Canyon National Recreation Area. 7.70 Section 7.70 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... in excess of flat wake speed on the Escalante River from Cow Canyon to Coyote Creek. (3) After...

36 CFR 7.70 - Glen Canyon National Recreation Area.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Glen Canyon National Recreation Area. 7.70 Section 7.70 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... in excess of flat wake speed on the Escalante River from Cow Canyon to Coyote Creek. (3) After...

36 CFR 7.70 - Glen Canyon National Recreation Area.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Glen Canyon National Recreation Area. 7.70 Section 7.70 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... in excess of flat wake speed on the Escalante River from Cow Canyon to Coyote Creek. (3) After...

Megabenthic assemblages at the Hudson Canyon head (NW Atlantic margin): Habitat-faunal relationships

NASA Astrophysics Data System (ADS)

Pierdomenico, Martina; Gori, Andrea; Guida, Vincent G.; Gili, Josep-Maria

2017-09-01

The distribution of megabenthic communities at the head of Hudson Canyon and adjacent continental shelf was studied by means of underwater video transects and still photo imagery collected using a towed camera system. The goal was to explore the relationships between faunal distribution and physical seafloor conditions and to test the hypothesis that increased seafloor heterogeneity in the Hudson Canyon supports a larger diversity of benthic communities, compared with the adjacent continental shelf. Hierarchical cluster analysis was performed to identify benthic assemblages as defined in imagery. The BIO-ENV procedure and the Canonical Correspondence Analysis were carried out to elucidate species groupings in relation to terrain variables extracted from bathymetric data. Species accumulation curves were generated to evaluate species turn over in and out of Hudson Canyon. The results indicate that seafloor morphology is the main physical factor related to benthic community composition and distribution. Assemblages dominated by sponges, zoanthids and cup corals colonized the canyon margins and flanks, and were associated with coarse-grained sediments, while sea pen assemblages were observed along muddy seafloor within the thalweg. An assemblage dominated by sea stars occurred on the shelf, associated with a sandy seafloor. Some assemblages were exclusively observed in the canyon area, suggesting that the increased variability of seafloor composition, together with the oceanographic processes specific to the canyon area, enhance beta diversity. The colonization by benthic suspension feeders within the canyon, in contrast to shelf assemblages, mainly composed of carnivores and detritus feeders could be favored the intense hydrodynamics at the canyon head that increase the availability of suspended organic matter. From the perspective of management and conservation of marine resources, the results obtained support the relevance of Hudson Canyon as a biodiversity hotspot

Dammed or Damned?

ERIC Educational Resources Information Center

Hirsch, Philip

1988-01-01

Summarizes issues raised at a workshop on "People and Dams" organized by the Society for Participatory Research in Asia. Objectives were to (1) understand problems created by dams for people, (2) consider forces affecting displaced populations and rehabilitation efforts, and (3) gain a perspective on popular education efforts among…

Submarine canyons represent an essential habitat network for krill hotspots in a Large Marine Ecosystem.

PubMed

Santora, Jarrod A; Zeno, Ramona; Dorman, Jeffrey G; Sydeman, William J

2018-05-15

Submarine canyon systems are ubiquitous features of marine ecosystems, known to support high levels of biodiversity. Canyons may be important to benthic-pelagic ecosystem coupling, but their role in concentrating plankton and structuring pelagic communities is not well known. We hypothesize that at the scale of a large marine ecosystem, canyons provide a critical habitat network, which maintain energy flow and trophic interactions. We evaluate canyon characteristics relative to the distribution and abundance of krill, critically important prey in the California Current Ecosystem. Using a geological database, we conducted a census of canyon locations, evaluated their dimensions, and quantified functional relationships with krill hotspots (i.e., sites of persistently elevated abundance) derived from hydro-acoustic surveys. We found that 76% of krill hotspots occurred within and adjacent to canyons. Most krill hotspots were associated with large shelf-incising canyons. Krill hotspots and canyon dimensions displayed similar coherence as a function of latitude and indicate a potential regional habitat network. The latitudinal migration of many fish, seabirds and mammals may be enhanced by using this canyon-krill network to maintain foraging opportunities. Biogeographic assessments and predictions of krill and krill-predator distributions under climate change may be improved by accounting for canyons in habitat models.

The formation and failure of natural dams

USGS Publications Warehouse

Costa, J.E.; Schuster, R.L.

1987-01-01

Of the numerous kinds of dams that form by natural processes, dams formed from landslides, glacial ice, and neoglacial moraines present the greatest threat to people and property. The most common types of mass movements that form landslide dams are rock and debris avalanches, rock and soil slumps and slides, and mud, debris, and earth flows. The most common initiation mechanisms for dam-forming landslides are excessive rainfall and snowmelt and earthquakes. Landslide dams can be classified into six categories based on their relation with the valley floor. Type I dams (11%) of the 81 landslide dams around the world that were classifed do not reach from one valley side to the other. Type II dams (44%) span the entire valley flood, occasionally depositing material high up on opposite valley sides. Type III dams (41%) move considerable distances both upstream and downstream from the landslide failure. Type IV dams (1%) are rare and involve the contemporaneous failure of material from both sides of a valley. Type V dams (1%) are also rare, and are created when a single landslide sends multiple tongues of debris into a valley forming two or more landslide dams in the same surfaces, that extend under the stream or valley and emerge on the opposite valley side. Many landslide dams fail shortly after formation. Overtopping is by far the most common cause of failure. Glacial ice dams can produce at least nine kinds of ice-dammed lakes. The most dangerous are lakes formed in main valleys dammed by tributary glaciers. Failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam. Cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel. Warmer temperate-ice dams tend to fail by sudden englacial or subglacial breaching and drainage. Late neoglacial moraine-dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several

4. VISTA POINT AND INTERPRETIVE PLAQUE AT LEE VINING CANYON. ...

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

4. VISTA POINT AND INTERPRETIVE PLAQUE AT LEE VINING CANYON. NOTE ROAD CUT ON CANYON WALL. LOOKING NNE. GIS: N-37 56 30.3 / 119 13 44.8 - Tioga Road, Between Crane Flat & Tioga Pass, Yosemite Village, Mariposa County, CA

A ravenous river reclaims its true course: the tale of Marmot Dam''s demise

Treesearch

Noreen Parks; Gordon Grant

2009-01-01

Removing dams that are outdated, unsafe, or pose significant economic or environmental costs has emerged in the last 10 years as a major river restoration strategy. The removal of the 45-foot-high Marmot Dam on the Sandy River in 2007 resulted in the biggest sediment release accompanying any dam removal to date. It also provided an unprecedented opportunity...

36 CFR 7.92 - Bighorn Canyon National Recreation Area.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bighorn Canyon National Recreation Area. 7.92 Section 7.92 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.92 Bighorn Canyon National Recreation Area. (a) Aircraft-designated...