Science.gov

Sample records for estuary engineering feasibility

  1. New Bedford Harbor Superfund Project, Acushnet River Estuary Engineering Feasibility Study of Dredging and Dredged Material Disposal Alternatives. Report 11. Evaluation of Conceptual Dredging and Disposal Alternatives

    DTIC Science & Technology

    1989-07-01

    unless so designated by other authorized documents. The contents of this report are not to be used for advertising, publication, or promotional purposes...prepared by the US Army Engineer Waterways Experiment Station (WES) and the New England Division (NED), USACE. Coordination and management support...between August 1985 and July 1988. Project manager for the USEPA was Mr. Frank Ciavattieri. The NED project managers were Messrs. Mark J. Otis and Alan

  2. Deschutes estuary feasibility study: hydrodynamics and sediment transport modeling

    USGS Publications Warehouse

    George, Douglas A.; Gelfenbaum, Guy; Lesser, Giles; Stevens, Andrew W.

    2006-01-01

    - Provide the completed study to the CLAMP Steering Committee so that a recommendation about a long-term aquatic environment of the basin can be made. The hydrodynamic and sediment transport modeling task developed a number of different model simulations using a process-based morphological model, Delft3D, to help address these goals. Modeling results provide a qualitative assessment of estuarine behavior both prior to dam construction and after various post-dam removal scenarios. Quantitative data from the model is used in the companion biological assessment and engineering design components of the overall study. Overall, the modeling study found that after dam removal, tidal and estuarine processes are immediately restored, with marine water from Budd Inlet carried into North and Middle Basin on each rising tide and mud flats being exposed with each falling tide. Within the first year after dam removal, tidal processes, along with the occasional river floods, act to modify the estuary bed by redistributing sediment through erosion and deposition. The morphological response of the bed is rapid during the first couple of years, then slows as a dynamic equilibrium is reached within three to five years. By ten years after dam removal, the overall hydrodynamic and morphologic behavior of the estuary is similar to the pre-dam estuary, with the exception of South Basin, which has been permanently modified by human activities. In addition to a qualitative assessment of estuarine behavior, process-based modeling provides the ability address specific questions to help to inform decision-making. Considering that predicting future conditions of a complex estuarine environment is wrought with uncertainties, quantitative results in this report are often expressed in terms of ranges of possible outcomes.

  3. Historical changes in the Columbia River estuary based on sediment cores: feasibility studies

    USGS Publications Warehouse

    Petersen, J.H.; Reisenbichler, R.; Gelfenbaum, G.R.; Peterson, C.; Baker, D.; Leavitt, P.R.; Simenstad, C.A.; Prahl, F.G.

    2003-01-01

    The importance of the Columbia River estuary to salmon, other fishes, migratory birds, and other species is fairly well established. Relatively little is known, however, about long-term, historic variations in biological processes and conditions within the estuary. For example, have conditions varied greatly with climatic regime shifts and how has dam construction on the Columbia River influenced biological communities over time? We conducted a feasibility study to see if sediment cores from the estuary could be aged and whether biological or contaminant indicators could be identified. Such information could be useful in understanding long-term environmental variation and in restoration studies.

  4. Artemis: Results of the engineering feasibility study

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Information is given in viewgraph form for the Engineering Feasibility Study of the Artemis Project, a plan to establish a permanent base on the Moon. Topics covered include the Common Lunar Lander (CLL), lunar lander engineering study results, lunar lander trajectory analysis, lunar lander conceptual design and mass properties, the lunar lander communication subsystem design, and product assurance.

  5. Feasibility study for convertible engine torque converter

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The feasibility study has shown that a dump/fill type torque converter has excellent potential for the convertible fan/shaft engine. The torque converter space requirement permits internal housing within the normal flow path of a turbofan engine at acceptable engine weight. The unit permits operating the engine in the turboshaft mode by decoupling the fan. To convert to turbofan mode, the torque converter overdrive capability bring the fan speed up to the power turbine speed to permit engagement of a mechanical lockup device when the shaft speed are synchronized. The conversion to turbofan mode can be made without drop of power turbine speed in less than 10 sec. Total thrust delivered to the aircraft by the proprotor, fan, and engine during tansient can be controlled to prevent loss of air speed or altitude. Heat rejection to the oil is low, and additional oil cooling capacity is not required. The turbofan engine aerodynamic design is basically uncompromised by convertibility and allows proper fan design for quiet and efficient cruise operation. Although the results of the feasibility study are exceedingly encouraging, it must be noted that they are based on extrapolation of limited existing data on torque converters. A component test program with three trial torque converter designs and concurrent computer modeling for fluid flow, stress, and dynamics, updated with test results from each unit, is recommended.

  6. Restoration of Hydrodynamic and Hydrologic Processes in the Chinook River Estuary, Washington – Feasibility Assessment

    SciTech Connect

    Khangaonkar, Tarang P.; Breithaupt, Stephen A.; Kristanovich, Felix C.

    2006-01-01

    A hydrodynamic and hydrologic modeling analysis was conducted to evaluate the feasibility of restoring natural estuarine functions and tidal marine wetlands habitat in the Chinook River estuary, located near the mouth of the Columbia River in Washington. The reduction in salmonid populations is attributable primarily to the construction of a Highway 101 overpass across the mouth of the Chinook River in the early 1920s with a tide gate under the overpass. This construction, which was designed to eliminate tidal action in the estuary, has impeded the upstream passage of salmonids. The goal of the Chinook River Restoration Project is to restore tidal functions through the estuary, by removing the tide gate at the mouth of the river, filling drainage ditches, restoring tidal swales, and reforesting riparian areas. The hydrologic model (HEC-HMS) was used to compute Chinook River and tributary inflows for use as input to the hydrodynamic model at the project area boundary. The hydrodynamic model (RMA-10) was used to generate information on water levels, velocities, salinity, and inundation during both normal tides and 100-year storm conditions under existing conditions and under the restoration alternatives. The RMA-10 model was extended well upstream of the normal tidal flats into the watershed domain to correctly simulate flooding anddrainage with tidal effects included, using the wetting and drying schemes. The major conclusion of the hydrologic and hydrodynamic modeling study was that restoration of the tidal functions in the Chinook River estuary would be feasible through opening or removal of the tide gate. Implementation of the preferred alternative (removal of the tide gate, restoration of the channel under Hwy 101 to a 200-foot width, and construction of an internal levee inside the project area) would provide the required restorations benefits (inundation, habitat, velocities, and salinity penetration, etc.) and meet flood protection requirements. The

  7. Restoration of Hydrodynamic and Hydrologic Processes in the Chinook River Estuary, Washington – Feasibility Assessment

    SciTech Connect

    Khangaonkar, Tarang P.; Breithaupt, Stephen A.; Kristanovich, Felix C.

    2006-08-03

    A hydrodynamic and hydrologic modeling analysis was conducted to evaluate the feasibility of restoring natural estuarine functions and tidal marine wetlands habitat in the Chinook River estuary, located near the mouth of the Columbia River in Washington. The reduction in salmonid populations is attributable primarily to the construction of a Highway 101 overpass across the mouth of the Chinook River in the early 1920s with a tide gate under the overpass. This construction, which was designed to eliminate tidal action in the estuary, has impeded the upstream passage of salmonids. The goal of the Chinook River Restoration Project is to restore tidal functions through the estuary, by removing the tide gate at the mouth of the river, filling drainage ditches, restoring tidal swales, and reforesting riparian areas. The hydrologic model (HEC-HMS) was used to compute Chinook River and tributary inflows for use as input to the hydrodynamic model at the project area boundary. The hydrodynamic model (RMA-10) was used to generate information on water levels, velocities, salinity, and inundation during both normal tides and 100-year storm conditions under existing conditions and under the restoration alternatives. The RMA-10 model was extended well upstream of the normal tidal flats into the watershed domain to correctly simulate flooding and drainage with tidal effects included, using the wetting and drying schemes. The major conclusion of the hydrologic and hydrodynamic modeling study was that restoration of the tidal functions in the Chinook River estuary would be feasible through opening or removal of the tide gate. Implementation of the preferred alternative (removal of the tide gate, restoration of the channel under Hwy 101 to a 200-foot width, and construction of an internal levee inside the project area) would provide the required restorations benefits (inundation, habitat, velocities, and salinity penetration, etc.) and meet flood protection requirements. The

  8. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon

    EPA Science Inventory

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  9. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon - April 2009

    EPA Science Inventory

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  10. Laser engines operating by resonance absorption. [thermodynamic feasibility study

    NASA Technical Reports Server (NTRS)

    Garbuny, M.; Pechersky, M. J.

    1976-01-01

    Basic tutorial article on the thermodynamic feasibility of laser engines at the present state of the art. Three main options are considered: (1) laser power applied externally to a heat reservoir (boiler approach); (2) internal heating of working fluid by resonance absorption; and (3) direct conversion of selective excitation into work. Only (2) is considered practically feasible at present. Basic concepts and variants, efficiency relations, upper temperature limits of laser engines, selection of absorbing gases, engine walls, bleaching, thermodynamic cycles of optimized laser engines, laser-powered turbines, laser heat pumps are discussed. Photon engines and laser dissociation engines are also considered.

  11. Decadal morphological evolution of the Yangtze Estuary in response to river input changes and estuarine engineering projects

    NASA Astrophysics Data System (ADS)

    Luan, Hua Long; Ding, Ping Xing; Wang, Zheng Bing; Ge, Jian Zhong; Yang, Shi Lun

    2016-07-01

    The Yangtze Estuary in China has been intensively influenced by human activities including altered river and sediment discharges in its catchment and local engineering projects in the estuary over the past half century. River sediment discharge has significantly decreased since the 1980s because of upstream dam construction and water-soil conservation. We analyzed bathymetric data from the Yangtze Estuary between 1958 and 2010 and divided the entire estuary into two sections: inner estuary and mouth bar area. The deposition and erosion pattern exhibited strong temporal and spatial variations. The inner estuary and mouth bar area underwent different changes. The inner estuary was altered from sedimentation to erosion primarily at an intermediate depth (5-15 m) along with river sediment decline. In contrast, the mouth bar area showed continued accretion throughout the study period. The frequent river floods during the 1990s and simultaneously decreasing river sediment probably induced the peak erosion of the inner estuary in 1986-1997. We conclude that both sediment discharge and river flood events played important roles in the decadal morphological evolution of the Yangtze Estuary. Regarding the dredged sediment, the highest net accretion rate occurred in the North Passage where jetties and groins were constructed to regulate the navigation channel in 1997-2010. In this period, the jetties induced enhanced deposition at the East Hengsha Mudflat and the high accretion rate within the mouth bar area was maintained. The impacts of estuarine engineering projects on morphological change extended beyond their sites.

  12. 75 FR 77798 - Interpretation of OSHA's Provisions for Feasible Administrative or Engineering Controls of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-14

    ... for Feasible Administrative or Engineering Controls of Occupational Noise AGENCY: Occupational Safety... Interpretation of OSHA's Provisions for Feasible Administrative or Engineering Controls of Occupational Noise... Interpretation of OSHA's Provisions for Feasible Administrative or Engineering Controls of Occupational...

  13. Magma energy: engineering feasibility of energy extraction from magma bodies

    SciTech Connect

    Traeger, R.K.

    1983-12-01

    A research program was carried out from 1975 to 1982 to evaluate the scientific feasibility of extracting energy from magma, i.e., to determine if there were any fundamental scientific roadblocks to tapping molten magma bodies at depth. The next stage of the program is to evaluate the engineering feasibility of extracting energy from magma bodies and to provide insight into system economics. This report summarizes the plans, schedules and estimated costs for the engineering feasibility study. Tentative tasks and schedules are presented for discussion and critique. A bibliography of past publications on magma energy is appended for further reference. 69 references.

  14. Recruitment dynamics of two ecosystem engineers could drive shellfish populations in U.S. west coast estuaries

    EPA Science Inventory

    Two species of burrowing shrimp, Neotrypaea californiensis and Upogebia pugettensis are important members of intertidal mudflat communities in US West coast estuaries. Both species act as ecosystem engineers and influence the presence of other structured habitats and suspension ...

  15. Disturbance facilitates the coexistence of antagonistic ecosystem engineers in California estuaries.

    PubMed

    Castorani, Max C N; Hovel, Kevin A; Williams, Susan L; Baskett, Marissa L

    2014-08-01

    Ecological theory predicts that interactions between antagonistic ecosystem engineers can lead to local competitive exclusion, but disturbance can facilitate broader coexistence. However, few empirical studies have tested the potential for disturbance to mediate competition between engineers. We examined the capacity for disturbance and habitat modification to explain the disjunct distributions of two benthic ecosystem engineers, eelgrass Zostera marina and the burrowing ghost shrimp Neotrypaea californiensis, in two California estuaries. Sediment sampling in eelgrass and ghost shrimp patches revealed that ghost shrimp change benthic biogeochemistry over small scales (centimeters) but not patch scales (meters to tens of meters), suggesting a limited capacity for sediment modification to explain species distributions. To determine the relative competitive abilities of engineers, we conducted reciprocal transplantations of ghost shrimp and eelgrass. Local ghost shrimp densities declined rapidly following the addition of eelgrass, and transplanted eelgrass expanded laterally into the surrounding ghost shrimp-dominated areas. When transplanted into eelgrass patches, ghost shrimp failed to persist. Ghost shrimp were also displaced from plots with structural mimics of eelgrass rhizomes and roots, suggesting that autogenic habitat modification by eelgrass is an important mechanism determining ghost shrimp distributions. However, ghost shrimp were able to rapidly colonize experimental disturbances to eelgrass patch edges, which are common in shallow estuaries. We conclude that coexistence in this system is maintained by spatiotemporally asynchronous disturbances and a competition-colonization trade-off: eelgrass is a competitively superior ecosystem engineer, but benthic disturbances permit the coexistence of ghost shrimp at the landscape scale by modulating the availability of space.

  16. 75 FR 64216 - Interpretation of OSHA's Provisions for Feasible Administrative or Engineering Controls of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-19

    ... for Feasible Administrative or Engineering Controls of Occupational Noise AGENCY: Occupational Safety... OSHA's official interpretation of the term feasible administrative or engineering controls as used in... standards. Under the standard, employers must use administrative or engineering controls rather...

  17. Development of an integrated indicator system to assess the impacts of reclamation engineering on a river estuary.

    PubMed

    Xu, Yan; Cai, Yanpeng; Sun, Tao; Yin, Xin'An; Tan, Qian

    2017-03-30

    An integrated indicator system was developed for determining synthetic environmental responses under multiple types of coastal reclamation engineering in the Yellow River estuary, China. Four types of coastal engineering works were analyzed, namely port construction, petroleum exploitation, fishery and aquaculture, and seawall defense. In addition, two areas with limited human disturbances were considered for comparison. From the weights of the response value for each indicator, port construction was determined to be the primary impact contributor among the four engineering works studies. Specifically, hydrodynamic conditions, ecological status, economic costs, and engineering intensity were on average 72.78%, 65.03%, 75.03%, and 66.35% higher than those of other engineering types. Furthermore, fishery and aquaculture impact on water quality was 42.51% higher than that of other engineering types, whereas seawall defense impact on landscape variation was 51.75% higher than that of other engineering types. The proposed indicator system may provide effective coastal management in future.

  18. Turning the Tide: Estuaries Shaped by Channel-Shoal Interactions, Eco-engineers and Inherited Landscapes

    NASA Astrophysics Data System (ADS)

    Kleinhans, M. G.; Braat, L.; Leuven, J.; Baar, A. W.; van der Vegt, M.; Van Maarseveen, M. C. G.; Markies, H.; Roosendaal, C.; van Eijk, A.

    2015-12-01

    Estuaries exhibit correlations between inlet dimensions, tidal prism and intertidal area, but to what extent estuary planform shape and shoal patterns resulted from biomorphological processes or from inherited conditions such as coastal plain and drowned valley dimensions remains unclear. We explore the hypothesis that mud flats and vegetation as a self-formed lateral confinement have effects analogous to that of river floodplain on braided versus meandering river patterns. Here we use the Delft3D numerical model and a novel tidal flume setup, the Metronome, to create estuaries from idealized initial conditions, with and without mud supply at the fluvial boundary. Experimental mud was simulated by crushed nutshell. Both the numerical and experimental estuaries were narrower with increasing mud, and had a lower degree of channel braiding. The experimental estuaries developed meanders at the river boundary with floodplain developing on the pointbar whereas cohesionless cases were more dynamic.

  19. MORE THAN JUST BAIT: BURROWING SHRIMP AS ECOSYSTEM ENGINEERS IN OREGON ESTUARIES - SEPTEMBER 2006

    EPA Science Inventory

    Burrowing shrimp may be most widely known as excellent fishing bait, but they also play important roles in estuaries of the Pacific Northwest. These shrimps strongly affect carbon and nutrient cycling, phytoplankton abundance, food web structure and dynamics, sediment stability,...

  20. Feasibility of magnetic bearings for advanced gas turbine engines

    NASA Technical Reports Server (NTRS)

    Hibner, David; Rosado, Lewis

    1992-01-01

    The application of active magnetic bearings to advanced gas turbine engines will provide a product with major improvements compared to current oil lubricated bearing designs. A rethinking of the engine rotating and static structure design is necessary and will provide the designer with significantly more freedom to meet the demanding goals of improved performance, increased durability, higher reliability, and increased thrust to weight ratio via engine weight reduction. The product specific technology necessary for this high speed, high temperature, dynamically complex application has been defined. The resulting benefits from this approach to aircraft engine rotor support and the complementary engine changes and improvements have been assessed.

  1. Feasibility of magnetic bearings for advanced gas turbine engines

    NASA Astrophysics Data System (ADS)

    Hibner, David; Rosado, Lewis

    1992-05-01

    The application of active magnetic bearings to advanced gas turbine engines will provide a product with major improvements compared to current oil lubricated bearing designs. A rethinking of the engine rotating and static structure design is necessary and will provide the designer with significantly more freedom to meet the demanding goals of improved performance, increased durability, higher reliability, and increased thrust to weight ratio via engine weight reduction. The product specific technology necessary for this high speed, high temperature, dynamically complex application has been defined. The resulting benefits from this approach to aircraft engine rotor support and the complementary engine changes and improvements have been assessed.

  2. The Feasibility of Oil Analysis for Air Force Diesel Engines

    DTIC Science & Technology

    1979-06-01

    period 18 September 1978 to 18 June 1979. The Air F’orce Project Monitor was MrW~ le MaW e, - an rton16h ALC /MMET,’ . Mr. J,P. Cuellar, Jr., of SwRI...insolub les 28 TABLE 5. RELATION OF USED CRANKCASE OIL ANALYSIS TO ENGINE CONDITION OR OPERATION (Cont’d) Contributing Engine Condition Test Result...guidelines for wearmetal and lubricant control limits. 46. Schilling, A. (Chief Engineer, Institut Francais du Petrole ), Automobile Engine Lubrication, 1972

  3. Exoskeletal Engine Concept: Feasibility Studies for Medium and Small Thrust Engines

    NASA Technical Reports Server (NTRS)

    Halliwell, Ian

    2001-01-01

    The exoskeletal engine concept is one in which the shafts and disks are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Omission of the shafts and disks leads to an open channel at the engine centerline. This has immense potential for reduced jet noise and for the accomodation of an alternative form of thruster for use in a combined cycle. The use of ceramic composite materials has the potential for significantly reduced weight as well as higher working temperatures without cooling air. The exoskeletal configuration is also a natural stepping-stone to complete counter-rotating turbomachinery. Ultimately this will lead to reductions in weight, length, parts count and improved efficiency. The feasibility studies are in three parts. Part I-Systems and Component Requirements addressed the mechanical aspects of components from a functionality perspective. This effort laid the groundwork for preliminary design studies. Although important, it is not felt to be particularly original, and has therefore not been included in the current overview. Part 2-Preliminary Design Studies turned to some of the cycle and performance issues inherent in an exoskeletal configuration and some initial attempts at preliminary design of turbomachinery were described. Twin-spoon and single-spool 25.800-lbf-thrust turbofans were used as reference vehicles in a mid-size commercial subsonic category in addition to a single-spool 5,000-lbf-thrust turbofan that represented a general aviation application. The exoskeletal engine, with its open centerline, has tremendous potential for noise suppression and some preliminary analysis was done which began to quantify the benefits. Part 3-Additional Preliminary Design Studies revisited the design of single-spool 25,800-lbf-thrust turbofan configurations, but in addition to the original FPR = 1.6 and BPR = 5.1 reference engine, two additional configurations used FPR = 2.4 and BPR = 3.0 and FPR = 3.2 and BPR

  4. Exoskeletal Engine Concept: Feasibility Studies for Medium and Small Thrust Engines

    NASA Technical Reports Server (NTRS)

    Halliwell, Ian

    2001-01-01

    The exoskeletal engine concept is one in which the shafts and disks are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Omission of the shafts and disks leads to an open channel at the engine centerline. This has immense potential for reduced jet noise and for the accommodation of an alternative form of thruster for use in a combined cycle. The use of ceramic composite materials has the potential for significantly reduced weight as well as higher working temperatures without cooling air. The exoskeletal configuration is also a natural stepping-stone to complete counter-rotating turbomachinery. Ultimately this will lead to reductions in weight, length, parts count and improved efficiency. The feasibility studies are in three parts. Part 1: Systems and Component Requirements addressed the mechanical aspects of components from a functionality perspective. This effort laid the groundwork for preliminary design studies. Although important, it is not felt to be particularly original, and has therefore not been included in the current overview. Part 2: Preliminary Design Studies turned to some of the cycle and performance issues inherent in an exoskeletal configuration and some initial attempts at preliminary design of turbomachinery were described. Twin-spoon and single-spool 25,800-lbf-thrust turbofans were used as reference vehicles in a mid-size commercial subsonic category in addition to a single-spool 5,000-lbf-thrust turbofan that represented a general aviation application. The exoskeletal engine, with its open centerline, has tremendous potential for noise suppression and some preliminary analysis was done which began to quantify the benefits. Part 3: Additional Preliminary Design Studies revisited the design of single-spool 25,800-lbf-thrust turbofan configurations, but in addition to the original FPR = 1.6 and BPR = 5.1 reference engine. two additional configurations used FPR = 2.4 and BPR = 3.0 and FPR = 3.2 and

  5. Session 6: Magma Energy: Engineering Feasibility of Energy Extraction from Magma Bodies

    SciTech Connect

    Traeger, R.K.

    1983-12-01

    Extensive quantities of high-quality energy are estimated to be available from molten magma bodies existing within 10 Km of the US continent's surface. A five-year study sponsored by DOE/BES demonstrated that extraction of energy from these melts was scientifically feasible. The next stage of assessment is to evaluate the engineering feasibility of energy extraction and provide a preliminary economic evaluation. Should the second step demonstrate engineering feasibility, the third step would include detailed economic, market and commercialization endeavors. Evaluation of the engineering feasibility will be initiated in FY 84 in a program supported by DOE/GHTD and managed by Dave Allen. The project will be managed by Sandia Labs in James Kelsey's Geothermal Technology Development Division. The project will continue to draw on expertise throughout the country, especially the scientific base established in the previous BES Magma Energy Program.

  6. Will the balance of power shift among native eastern Pacific estuary ecosystem engineers with the introduced bopyrid isopod parasite orthione griffenis?

    EPA Science Inventory

    The blue mud shrimp, Upogebia pugettensis, the bay ghost shrimp, Neotrypaea californiensis, and eelgrass, Zostera marina are endemic ecosystem engineers that define the ecological structure and function of estuaries along the Pacific coast of the US as significantly as do marshes...

  7. Subseabed Radioactive Waste Disposal Feasibility Program: ocean engineering challenges for the 80's

    SciTech Connect

    Talbert, D. M.

    1980-01-01

    The objective of the Subseabed Disposal Program is to assess the feasibility of disposing of high-level radioactive wastes or spent fuel in suitable geologic formations beneath the deep ocean floor. The program is entering a phase which will address engineering feasibility. While the current phase of the program to determine the scientific and environmental feasibility of the concept is not yet complete, activities to assess the engineering aspects are being initiated in parallel to facilitate the development of the concept on a time scale commensurate with other related programs both in the United States and abroad. It is anticipated that engineering aspects will become the central focus of the program during the early 80's and will continue so through the establishment of a pilot-plant level activity which could occur by the mid-90's.

  8. A Feasibility Study of Life-Extending Controls for Aircraft Turbine Engines Using a Generic Air Force Model (Preprint)

    DTIC Science & Technology

    2006-12-01

    engine model is a detailed, physics-based engine model of a two-spool, non-augmented, low bypass ratio engine developed using MATLAB/ Simulink ® [9]. The...AFRL-PR-WP-TP-2007-218 A FEASIBILITY STUDY OF LIFE- EXTENDING CONTROLS FOR AIRCRAFT TURBINE ENGINES USING A GENERIC AIR FORCE MODEL (PREPRINT...SUBTITLE A FEASIBILITY STUDY OF LIFE-EXTENDING CONTROLS FOR AIRCRAFT TURBINE ENGINES USING A GENERIC AIR FORCE MODEL (PREPRINT) 5c. PROGRAM ELEMENT

  9. Krypton-85 hydrofracture engineering feasibility and safety evaluation

    SciTech Connect

    Peretz, F.J.; Muller, M.E.; Pan, P.Y.

    1981-07-01

    Engineering studies have been made to determine the hazards associated with the disposal of /sup 85/Kr using the hydrofracture process. To assess the hazards, an effort has been made to identify the equipment required to entrain and dissolve the noble gas into the grout stream at hydrofracture pressure (up to 350 bar). Off-the-shelf or slightly modified equipment has been identified for safe and effective compression and gas-grout mixing. Each monthly injection disposes of 1.6 x 10/sup 6/ Ci of /sup 85/Kr. By connecting only one gas cylinder to the injection system at a time, the maximum amount of krypton likely to be released as a result of equipment failure is limited to 128,000 Ci. An evaluation by Los Alamos Technical Associates shows that releasing this amount of gas in less than one hour under worst-case meteorological conditions through a 30-m stack would result in a whole-body dose of 170 millirem at a distance of 1 km from the facility. A krypton collection and recovery system can further reduce this dose to 17 millirem; increasing the distance to the site boundary to 3 km can also reduce the dose by a factor of ten. Lung and skin dose estimates are 1.6 and 120 times the whole-body dose, respectively. These are all worst-case values; releases under more typical conditions would result in a significantly lower dose. No insurmountable safety or engineering problems have been identified.

  10. Geo-feasibility of in situ sediment capping in a Great Lakes urban estuary: a sediment budget assessment

    NASA Astrophysics Data System (ADS)

    Foyle, Anthony M.; Norton, Kevin P.

    2007-10-01

    Presque Isle Bay is one of 40 remaining environmental areas of concern (AoCs) on the North American Great Lakes that have one or more water, habitat, or sediment quality impairments as defined by the International Joint Commission. In situ natural capping using sediment from to-be-remediated watersheds and other potential sources is being considered as the most feasible means of remediating an existing contaminated sediment problem at this site. A multi-decade (˜40 year) sediment budget shows that, when localized anthropogenic effects (dredging, reclamation) are discounted, the bay net-accumulated sediment over time. Sediment was supplied from three major sources: bank erosion and bluff retreat (41%), streams (25%), and the Lake Erie littoral system (20%). The non-stream sources supply environmentally clean materials from ancient beach and glacio-lacustrine deposits along the shoreline, and from the modern littoral system. Organic and metallic contaminants supplied primarily by streams and run-off remain a remediation challenge for the AoC. Geologically, natural capping of contaminants over the next several decades is a viable solution for most of the bay. The mechanism may not work effectively in all areas because approximately 25% of the bay floor is moderately net-erosional while several localized areas accumulate sediments very slowly at decadal timescales.

  11. Converting an estuary to Lake Grevelingen: Environmental review of a coastal engineering project

    NASA Astrophysics Data System (ADS)

    Saeijs, H. L. F.; Stortelder, P. B. M.

    1982-09-01

    To guarantee protection from storm floods in the southwestern part of the Netherlands, the length of exposed coastline is being greatly reduced by the construction of dams and a storm surge barrier. As part of the Delta Project, the mouth of the Grevelingen estuary was closed in 1971. Due to the closure, tidal movement was eliminated, which resulted in changes in environmental factors such as transparency and chloride and phosphate concentration. The number of plant and animal groups decreased. Large areas of sand flats and salt marshes, which were formerly exposed to the tides, were left “high and dry.” This resulted in enormous changes for the communities living in these areas. The development of a new ecological system and the changed potential afforded by the water and land areas for human use, emphasized the need for physical planning. The potential uses (functions) of the new system are discussed in this article. Special attention is given to the demand for recreational facilities and nature conservation and to the balanced realization of these main functions. The methods applied in choosing between alternatives in physical planning are explained. Water quality and ecosystem management are discussed. One of the main management objectives is the prevention of a further decrease in the chloride concentration and the number of species. A sluice was, therefore, put into operation in 1978, by means of which water was exchanged between the North Sea and Lake Grevelingen. The responses observed are discussed here. In the near future, a crucial decision will have to be made: Will Lake Grevelingen remain a salt-water lake or will it become a fresh-water lake?

  12. Engine Company Evaluation of Feasibility of Aircraft Retrofit Water-Injected Turbomachines

    NASA Technical Reports Server (NTRS)

    Becker, Arthur

    2006-01-01

    This study supports the NASA Glenn Research Center and the U.S. Air Force Research Laboratory in their efforts to evaluate the effect of water injection on aircraft engine performance and emissions. In this study, water is only injected during the takeoff and initial climb phase of a flight. There is no water injection during engine start or ground operations, nor during climb, cruise, descent, or landing. This study determined the maintenance benefit of water injection during takeoff and initial climb and evaluated the feasibility of retrofitting a current production engine, the PW4062 (Pratt & Whitney, East Hartford, CT), with a water injection system. Predicted NO(x) emissions based on a 1:1 water-tofuel ratio are likely to be reduced between 30 to 60 percent in Environmental Protection Agency parameter (EPAP). The maintenance cost benefit for an idealized combustor water injection system installed on a PW4062 engine in a Boeing 747-400ER aircraft (The Boeing Company, Chicago, IL) is computed to be $22 per engine flight hour (EFH). Adding water injection as a retrofit kit would cost up to $375,000 per engine because of the required modifications to the fuel system and addition of the water supply system. There would also be significant nonrecurring costs associated with the development and certification of the system that may drive the system price beyond affordability.

  13. Geothermal resource, engineering and economic feasibility study for the City of Ouray, Colorado. Final report

    SciTech Connect

    Meyer, R.T.; Raskin, R.; Zocholl, J.R.

    1982-07-31

    A geothermal energy feasibility study has been performed for the City of Ouray, Colorado, to determine the potential economic development opportunities to the City. The resource assessment indicates the resource to be associated with the Ouray fault zone, the Leadville limestone formation, the high thermal gradient in the area of the San Juan mountains, and the recharge from precipitation in the adjacent mountains. Four engineering designs of alternative sizes, costs, applications, and years of start-up have been defined to offer the City a range of development scales. Life cycle cost analyses have been conducted for cases of both public and private ownership. All systems are found to be feasible on both economic and technical grounds. 49 refs., 8 figs.

  14. The electrochemical reduction of carbon dioxide to formate/formic acid: engineering and economic feasibility.

    PubMed

    Agarwal, Arun S; Zhai, Yumei; Hill, Davion; Sridhar, Narasi

    2011-09-19

    The engineering and economic feasibility of large-scale electrochemical reduction of carbon dioxide to formate salts and formic acid is the focus of this Full Paper. In our study we investigated the long-term performance of tin and other proprietary catalysts in the reduction of carbon dioxide to formate/formic acid at a gas/solid/liquid interface, using a flow-through reactor. The overall economics and energy consumption of the process are evaluated through a value chain analysis. The sensitivity of the net present value of the process to various process parameters is examined.

  15. Idaho Nuclear Technology and Engineering Center Newly Generated Liquid Waste Demonstration Project Feasibility Study

    SciTech Connect

    Herbst, A.K.

    2000-02-01

    A research, development, and demonstration project for the grouting of newly generated liquid waste (NGLW) at the Idaho Nuclear Technology and Engineering Center is considered feasible. NGLW is expected from process equipment waste, decontamination waste, analytical laboratory waste, fuel storage basin waste water, and high-level liquid waste evaporator condensate. The potential grouted waste would be classed as mixed low-level waste, stabilized and immobilized to meet RCRA LDR disposal in a grouting process in the CPP-604 facility, and then transported to the state.

  16. A hingeless rotor XV-15 design integration feasibility study. Volume 1: Engineering design studies

    NASA Technical Reports Server (NTRS)

    Magee, J. P.; Alexander, H. R.

    1978-01-01

    A design integration feasibility study was carried out to investigate what modifications to the basic XV-15 were necessary to accomplish a flight demonstration of the XV-15 with a Boeing hingeless rotor. Also investigated were additional modifications which would exploit the full capability provided by the combination of the new rotor and the existing T53 engine. An evaluation of the aircraft is presented and the data indicate improved air vehicle performance, acceptable aeroelastic margins, lower noise levels and improved flying qualities compared with the XV-15 aircraft. Inspection of the rotor system data provided shows an essentially unlimited life rotor for the flight spectrum anticipated for the XV-15.

  17. Feasibility Investigation on the Development of a Structural Damage Diagnostic and Monitoring System for Rocket Engines

    NASA Technical Reports Server (NTRS)

    Shen, Ji Y.; Sharpe, Lonnie, Jr.

    1998-01-01

    The research activity for this project is mainly to investigate the necessity and feasibility to develop a structural health monitoring system for rocket engines, and to carry out a research plan for further development of the system. More than one hundred technical papers have been searched and reviewed during the period. We concluded after this investigation that adding a new module in NASA's existing automated diagnostic system to monitor the healthy condition of rocket engine structures is a crucial task, and it's possible to develop such a system based upon the vibrational-based nondestructive damage assessment techniques. A number of such techniques have been introduced. Their advantages and disadvantages are also discussed. A global research plan has been figured out. As the first step of the overall research plan, a proposal for the next fiscal year has been submitted.

  18. Internal combustion engine with thermochemical recuperation fed by ethanol steam reforming products - feasibility study

    NASA Astrophysics Data System (ADS)

    Cesana, O.; Gutman, M.; Shapiro, M.; Tartakovsky, L.

    2016-08-01

    This research analyses the performance of a spark ignition engine fueled by ethanol steam reforming products. The basic concept involves the use of the internal combustion engine's (ICE) waste heat to promote onboard reforming of ethanol. The reformer and the engine performance were simulated and analyzed using GT-Suite, Chem CAD and Matlab software. The engine performance with different compositions of ethanol reforming products was analyzed, in order to find the optimal working conditions of the ICE - reformer system. The analysis performed demonstrated the capability to sustain the endothermic reactions in the reformer and to reform the liquid ethanol to hydrogen-rich gaseous fuel using the heat of the exhaust gases. However, the required reformer's size is quite large: 39 x 89 x 73 cm, which makes a feasibility of its mounting on board a vehicle questionable. A comparison with ICE fed by gasoline or liquid ethanol doesn't show a potential of efficiency improvement, but can be considered as a tool of additional emissions reduction.

  19. GEEF: a geothermal engineering and economic feasibility model. Description and user's manual

    SciTech Connect

    Not Available

    1982-09-01

    The model is designed to enable decision makers to compare the economics of geothermal projects with the economics of alternative energy systems at an early stage in the decision process. The geothermal engineering and economic feasibility computer model (GEEF) is written in FORTRAN IV language and can be run on a mainframe or a mini-computer system. An abbreviated version of the model is being developed for usage in conjunction with a programmable desk calculator. The GEEF model has two main segments, namely (i) the engineering design/cost segment and (ii) the economic analysis segment. In the engineering segment, the model determines the numbers of production and injection wells, heat exchanger design, operating parameters for the system, requirement of supplementary system (to augment the working fluid temperature if the resource temperature is not sufficiently high), and the fluid flow rates. The model can handle single stage systems as well as two stage cascaded systems in which the second stage may involve a space heating application after a process heat application in the first stage.

  20. Conceptual Design and Feasibility of Foil Bearings for Rotorcraft Engines: Hot Core Bearings

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2007-01-01

    Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include oil-free microturbines, motors, generators and turbochargers. The driving forces for integrating gas foil bearings into these high-speed systems are the benefits promised by removing the oil lubrication system. Elimination of the oil system leads to reduced emissions, increased reliability, and decreased maintenance costs. Another benefit is reduced power plant weight. For rotorcraft applications, this would be a major advantage, as every pound removed from the propulsion system results in a payload benefit.. Implementing foil gas bearings throughout a rotorcraft gas turbine engine is an important long-term goal that requires overcoming numerous technological hurdles. Adequate thrust bearing load capacity and potentially large gearbox applied radial loads are among them. However, by replacing the turbine end, or hot section, rolling element bearing with a gas foil bearing many of the above benefits can be realized. To this end, engine manufacturers are beginning to explore the possibilities of hot section gas foil bearings in propulsion engines. This overview presents a logical follow-on activity by analyzing a conceptual rotorcraft engine to determine the feasibility of a foil bearing supported core. Using a combination of rotordynamic analyses and a load capacity model, it is shown to be reasonable to consider a gas foil bearing core section. In addition, system level foil bearing testing capabilities at NASA Glenn Research Center are presented along with analysis work being conducted under NRA Cooperative Agreements.

  1. Engineering feasibility analysis for in-situ stabilization of Burrell Township site residues. [UMTRA

    SciTech Connect

    Not Available

    1982-11-01

    The Burrell Township site, located in western Pennsylvania, received approximately 11,600 tons of radioactively-contaminated material in late 1956 and early 1957 from the Vitro Manufacturing Company's operations in Canonsburg, Pennsylvania. WESTON was requested to conduct an engineering study to determine the feasibility of stabilizing the site in accordance with the US Environmental Protection Agency's (EPA) interim and proposed standards (45 FR 27366--27368, April 22, 1980, and 46 FR 2556--2563, January 9, 1981). The scope of this study is limited to those alternatives that can be implemented on the site and will not require removal and offsite disposal of radioactively-contaminated material. Four alternatives for control of the radioactive material at the Burrell site were considered and evaluated, as follows: 1. Site stabilization and closure. 2. Site control and containment. 3. Waste excavation and encapsulation. 4. Waste excavation, incineration, and encapsulation. 2 refs., 32 figs., 12 tabs.

  2. Decadal changes in the ichthyofauna of a eutrophic estuary following a remedial engineering modification and subsequent environmental shifts

    NASA Astrophysics Data System (ADS)

    Potter, Ian C.; Veale, Lauren; Tweedley, James R.; Clarke, K. Robert

    2016-11-01

    This study has determined how the characteristics of the ichthyofauna of a large eutrophic microtidal estuary changed, initially in response to major structural remedial modifications, and then, during later years, as the environment became further modified, due mainly to effects of climate change. Data on the ichthyofauna of the Peel-Harvey Estuary, in south-western Australia, were derived firstly by seining seasonally in five regions over two consecutive twelve months (two years) in 2008-10. These data were then collated with those recorded previously using the same sampling regime throughout 1980 and 1981, when massive macroalgal growths were present, and throughout 1996 and 1997, soon after the opening, in 1994, of an artificial, deep and second entrance channel. The latter resulted in greater tidal flushing, consistently high salinities and reduced macroalgal biomass. Ichthyofaunal composition changed significantly overall and in four of the five regions across the three periods. Although increased tidal exchange did not lead to a rise in the number either of those marine species that typically use estuaries as nursery areas (marine estuarine-opportunists) or of those that complete their life cycle within the estuary (estuarine residents), the contributions made by the abundances of the representatives of those two groups to the total catch of fish varied markedly between periods. Those differences were largely responsible for the inter-period changes in species composition. In contrast to the situation with marine estuarine-opportunists, increased tidal exchange and higher salinities resulted in a greater number of marine straggler species entering the system, albeit in low numbers. The ichthyofauna during 1980-81 contained relatively large numbers of species that are typically associated with macrophytes, including marine estuarine-opportunists, e.g. Pelates octolineatus, and estuarine residents e.g. Ostorhinchus rueppellii and Hyporhamphus regularis

  3. Engineering Feasibility and Trade Studies for the NASA/VSGC MicroMaps Space Mission

    NASA Technical Reports Server (NTRS)

    Abdelkhalik, Ossama O.; Nairouz, Bassem; Weaver, Timothy; Newman, Brett

    2003-01-01

    Knowledge of airborne CO concentrations is critical for accurate scientific prediction of global scale atmospheric behavior. MicroMaps is an existing NASA owned gas filter radiometer instrument designed for space-based measurement of atmospheric CO vertical profiles. Due to programmatic changes, the instrument does not have access to the space environment and is in storage. MicroMaps hardware has significant potential for filling a critical scientific need, thus motivating concept studies for new and innovative scientific spaceflight missions that would leverage the MicroMaps heritage and investment, and contribute to new CO distribution data. This report describes engineering feasibility and trade studies for the NASA/VSGC MicroMaps Space Mission. Conceptual studies encompass: 1) overall mission analysis and synthesis methodology, 2) major subsystem studies and detailed requirements development for an orbital platform option consisting of a small, single purpose spacecraft, 3) assessment of orbital platform option consisting of the International Space Station, and 4) survey of potential launch opportunities for gaining assess to orbit. Investigations are of a preliminary first-order nature. Results and recommendations from these activities are envisioned to support future MicroMaps Mission design decisions regarding program down select options leading to more advanced and mature phases.

  4. The Feasibility of Using Irreversible Electroporation to Introduce Pores in Bacterial Cellulose Scaffolds for Tissue Engineering

    PubMed Central

    Baah-Dwomoh, Adwoa; Rolong, Andrea; Gatenholm, Paul; Davalos, Rafael V.

    2015-01-01

    This work investigates the feasibility of the use of irreversible electroporation (IRE) in the biofabrication of 3D cellulose nanofibril networks via the bacterial strain Gluconacetobacter xylinus. IRE uses electrical pulses to increase membrane permeability by altering the transmembrane potential; past a threshold, damage to the cell becomes too great and leads to cell death. We hypothesized that using IRE to kill the bacteria at specific locations and particular times, we could introduce conduits in the overall scaffold by preventing cellulose biosynthesis locally. Through mathematical modeling and experimental techniques, electrical effects were investigated and the parameters for IRE of Gluconacetobacter xylinus were determined. We found that for a specific set of parameters, an applied electric field of 8 kV/cm to 12.5 kV/cm was sufficient to kill bacteria and create a localized pore. We also found that an applied electric field of 8 kV/cm to 12.5 kV/cm, which produces a local field of 3 kV/cm was sufficient to kill most of the bacteria and produce a localized pore, but an applied electric field of 17.5 kV/cm was required to kill all. Results suggest that IRE may be an effective tool to create scaffolds with appropriate porosity for orthopedic applications. Ideally, these engineered scaffolds could be used to successfully treat osteochondral defects. PMID:25690311

  5. CARS temperature measurements in the fuel preburner of the Space Shuttle main engine: A feasibility study

    NASA Technical Reports Server (NTRS)

    Beiting, E. J.; Luthe, J. C.

    1983-01-01

    This report discusses the feasibility of making temperature profile measurements in the fuel preburner of the main engine of the space shuttle (SSME) using coherent anti-Stokes Raman spectroscopy (CARS). The principal thrust of the work is to identify problems associated with making CARS measurements in high temperature gas phase hydrogen at very high pressures (approx 400 atmospheres). To this end a theoretical study was made of the characteristics of the CAR spectra of H2 as a function of temperature and pressure and the accuracy with which temperatures can be extracted from this spectra. In addition the experimental problems associated with carrying out these measurements on a SSME at NSTL were identified. A conceptual design of a CARS system suitable for this work is included. Many of the results of the calculations made in this report are plotted as a function of temperature. In the course of presenting these results, it was necessary to decide whether the number of density or the pressure should be treated as a fixed parameter.

  6. A feasibility study on using inkjet technology, micropumps, and MEMs as fuel injectors for bipropellant rocket engines

    NASA Astrophysics Data System (ADS)

    Glynne-Jones, Peter; Coletti, M.; White, N. M.; Gabriel, S. B.; Bramanti, C.

    2010-07-01

    Control over drop size distributions, injection rates, and geometrical distribution of fuel and oxidizer sprays in bi-propellant rocket engines has the potential to produce more efficient, more stable, less polluting rocket engines. This control also offers the potential of an engine that can be throttled, working efficiently over a wide range of output thrusts. Inkjet printing technologies, MEMS fuel atomizers, and piezoelectric injectors similar in concept to those used in diesel engines are considered for their potential to yield a new, more active injection scheme for a rocket engine. Inkjets are found to be unable to pump at sufficient pressures, and have possibly dangerous failure modes. Active injection is found to be feasible if high pressure drop along the injector plate is used. A conceptual design is presented and its basic behavior assessed.

  7. Feasibility Study of a Pressure-fed Engine for a Water Recoverable Space Shuttle Booster

    NASA Technical Reports Server (NTRS)

    Gerstl, E.

    1972-01-01

    Detailed mass properties are presented for a gimbaled, fixed thrust, regeneratively cooled engine having a coaxial pintle injector. The baseline design parameters for this engine are tabulated. Mass properties are also summarized for several other engine configurations i.e., a hinge nozzle using a Techroll seal, a gimbaled duct cooled engine and a regeneratively cooled engine using liquid injection thrust vector control (LITVC). Detailed engine analysis and design trade studies leading to the selection of a regeneratively cooled gimbaled engine and pertaining to the selection of the baseline design configuration are also given.

  8. Embedded Acoustic Sensor Array for Engine Fan Noise Source Diagnostic Test: Feasibility of Noise Telemetry via Wireless Smart Sensors

    NASA Technical Reports Server (NTRS)

    Zaman, Afroz; Bauch, Matthew; Raible, Daniel

    2011-01-01

    Aircraft engines have evolved into a highly complex system to meet ever-increasing demands. The evolution of engine technologies has primarily been driven by fuel efficiency, reliability, as well as engine noise concerns. One of the sources of engine noise is pressure fluctuations that are induced on the stator vanes. These local pressure fluctuations, once produced, propagate and coalesce with the pressure waves originating elsewhere on the stator to form a spinning pressure pattern. Depending on the duct geometry, air flow, and frequency of fluctuations, these spinning pressure patterns are self-sustaining and result in noise which eventually radiate to the far-field from engine. To investigate the nature of vane pressure fluctuations and the resulting engine noise, unsteady pressure signatures from an array of embedded acoustic sensors are recorded as a part of vane noise source diagnostics. Output time signatures from these sensors are routed to a control and data processing station adding complexity to the system and cable loss to the measured signal. "Smart" wireless sensors have data processing capability at the sensor locations which further increases the potential of wireless sensors. Smart sensors can process measured data locally and transmit only the important information through wireless communication. The aim of this wireless noise telemetry task was to demonstrate a single acoustic sensor wireless link for unsteady pressure measurement, and thus, establish the feasibility of distributed smart sensors scheme for aircraft engine vane surface unsteady pressure data transmission and characterization.

  9. CF6 jet engine performance improvement program. Task 1: Feasibility analysis

    NASA Technical Reports Server (NTRS)

    Fasching, W. A.

    1979-01-01

    Technical and economic engine improvement concepts selected for subsequent development include: (1) fan improvement; (2) short core exhaust; (3) HP turbine aerodynamic improvement; (4) HP turbine roundness control; (5) HP turbine active clearance control; and (6) cabin air recirculation. The fuel savings for the selected engine modification concepts for the CF6 fleet are estimated.

  10. Bio-geomorphology of estuaries: the need for understanding the balance between ecosystem engineering, physical forcing and biomechanical species interactions

    NASA Astrophysics Data System (ADS)

    Bouma, Tjeerd; Balke, Thorsten; van Belzen, Jim; Cozzoli, Francesco; Suykerbuyk, Wouter; van Katwijk, Marieke; Temmerman, Stijn; Herman, Peter

    2013-04-01

    The estuarine environment is strongly affected by the hydrodynamic forces from currents and waves, which often form both a resource and a stress to the organisms inhabiting these areas. Organisms that inhabit these areas interact with these physical forces, and may thereby modify their abiotic environment. This is referred to as ecosystem engineering (EE), which may result in locally improved growing conditions for the organisms. By their activities, ecosystem engineers (EE's) can have major influence on sediment dynamics in the coastal ecosystems and may create self-organised bio-geomorphologic landscapes. However, the physical-driven sediment dynamics may also impose control over organism establishment and performance. And on top of that, ecosystem engineering organisms may affect the occurrence of each other via their effect on the environment (i.e., 'biomechanical warfare'). The combination of these 3 types of interactions makes the dynamics of biogeomorphic ecosystems complex to understand and model, and restoration of biogeomorphic ecosystems hard to accomplish. In our presentation we will highlight 3 aspects that we see as crucial to improve our understanding, modelling and restoration of biogeomorphic ecosystems: (1) the possibility to generalise EE-effects across species (2) identifying to which extent physical forcing may enable vs. restrict EE-effects (3) understanding the biological and physical thresholds to the establishment of EE's, and the long-term dynamics of biogemorphic ecosystems. Each of these aspects will be discussed based on experimental results.

  11. rRNA (rrn) Operon-Engineered Bacillus subtilis as a Feasible Test Organism for Antibiotic Discovery

    PubMed Central

    Tanaka, Yukinori; Nanamiya, Hideaki; Yano, Koichi; Kakugawa, Koji; Kawamura, Fujio

    2013-01-01

    Bacillus subtilis contains 10 rRNA (rrn) operons. We found that rRNA operon-engineered B. subtilis strain RIK543, with only the rrnO operon, is specifically hypersensitive to RNA polymerase inhibitors such as rifamycin SV and rifampin (80-fold and 20-fold, respectively). In pilot screening experiments, we found actinomycete isolates successfully at an incidence of 1.9% (18/945) that produced antibacterials that were detectable only with RIK543 as the test organism. Strain RIK543 may be a feasible test organism for the discovery of novel RNA polymerase inhibitors. PMID:23335737

  12. Introduction to Estuaries

    EPA Science Inventory

    Estuaries, although minor geographical features at the global scale, have major importance for society and the world’s economies. This chapter introduces estuaries by presenting an overview of definitions, origins, physical, chemical and ecological attributes, and the interaction...

  13. Climate Ready Estuaries

    EPA Pesticide Factsheets

    Information on climate change impacts to different estuary regions, tools and resources to monitor changes, and information to help managers develop adaptation plans for risk management of estuaries and coastal communities.

  14. Estuary Data Mapper (EDM)

    EPA Pesticide Factsheets

    Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

  15. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    SciTech Connect

    Pratapas, John; Mather, Daniel; Kozlovsky, Anton

    2013-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen’s significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an

  16. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    SciTech Connect

    John Pratapas; Daniel Mather; Anton Kozlovsky

    2007-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen's significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an

  17. Engineering feasibility analysis for in-situ stabilization of Canonsburg residues. [UMTRA project

    SciTech Connect

    Not Available

    1982-01-01

    The US Department of Energy is considering several methods for carrying out remedial actions in Canonsburg, Pennsylvania, at the site of an inactive uranium-processing mill. The main objective of this study is to determine the feasibility of in-situ stabilization as the remedial action. In-situ stabilization is an alternative to site decontamination and offsite disposal. The problems associated with offsite hauling of large quantities of contaminated material and with the location and development of a new disposal site could be avoided by the implementation of an in-situ stabilization concept. In addition, the in-situ approach would be more cost-effective than offsite disposal. This study will establish that a technically feasible and implementable in-situ stabilization concept can be developed that meets regulatory requirements and is cost effective. This study in no way commits the DOE to implement any specific actions described herein. 11 refs., 30 figs., 24 tabs.

  18. Cost/feasibility considerations for off-shore engineering/construction

    SciTech Connect

    Sturges, R.K.; Harrison, J.G. )

    1988-01-01

    Considerable construction activity is now occurring in areas of the world where in-country engineering/construction capability is limited. This limitation requires the use of off-shore capabilities in conjunction with local engineering contractors (LEC's) to satisfy local legal requirements for use of on-shore services. While LEC's can provide the advantage of relatively inexpensive labor, it also brings the challenge of managing an international team given the difference in productivity and cultures. Procurement of equipment worldwide also has advantages and disadvantages. Government regulations relative to equipment purchased off-shore can be complex. Shipping considerations are significant when the existing infrastructure is taken into account, particularly when modular construction techniques are utilized. Understanding the contractual and documentation required takes a major effort. This paper addresses the complexities of off-shore engineering/construction from a management and cost perspective.

  19. Feasibility of Using Full Synthetic Low Viscosity Engine Oil at High Ambient Temperatures in U.S. Army Engines

    DTIC Science & Technology

    2011-06-01

    Average Std. Dev. Average Std. Dev. Engine Speed RPM 3200 1.1 900 5.4 Torque ft*lb 283.6 4.7 3.4 0.8 Fuel Flow lb/hr 75.7 0.9 3.9 0.1 Power bhp 172.8...2.9 0.6 0.1 BSFC lb/ bhp *hr 0.438 0.005 6.879 1.664 Temperatures: Coolant In °F 192.0 0.8 93.6 1.1 Coolant Out °F 205.9 0.7 99.8 0.9 Oil Sump °F 263.0...Average Std. Dev. Average Std. Dev. Engine Speed RPM 2400.0 1.0 750.2 6.2 Torque* ft*lb 618.0 21.7 4.3 10.1 Fuel Flow lb/hr 101.0 10.5 2.8 0.8 Power* bhp

  20. Feasibility of Field Test Kits for Assessing In-Service Condition of Army Engine Oils.

    DTIC Science & Technology

    1979-03-01

    spark-ignition engine service, and shotild not be used for diesel and/or synthetic motor oils possibly because the diesel oil contains soot . Also, a...NVKINII$i \\21110 ~ N LiO.\\ Ams4 iiiNNPNI.N it,182i 0I14 4iII iKIN%IPHOIbSI \\ \\41)1 I 11(.11 NI I N I)K4.’M I I \\I I 4OMiNINI H I’ N K\\IN I INk Nt

  1. JT8D and JT9D jet engine performance improvement program. Task 1: Feasibility analysis

    NASA Technical Reports Server (NTRS)

    Gaffin, W. O.; Webb, D. E.

    1979-01-01

    JT8D and JT9D component performance improvement concepts which have a high probability of incorporation into production engines were identified and ranked. An evaluation method based on airline payback period was developed for the purpose of identifying the most promising concepts. The method used available test data and analytical models along with conceptual/preliminary designs to predict the performance improvements, weight, installation characteristics, cost for new production and retrofit, maintenance cost, and qualitative characteristics of candidate concepts. These results were used to arrive at the concept payback period, which is the time required for an airline to recover the investment cost of concept implementation.

  2. Learning Lessons from Estuaries

    ERIC Educational Resources Information Center

    Schnittka, Christine

    2006-01-01

    There is something that draws all people to the sea and especially to the fertile estuaries that nuzzle up to its shores. An estuary serves as both a nursery and a grave for sea creatures. If life evolved from some primordial sea, it may well have been an estuary--a place where ocean and rivers meet and fresh and salty waters mingle in the…

  3. Feasibility of using a high-level waste canister as an engineered barrier in disposal

    SciTech Connect

    Slate, S.C.; Pitman, S.G.; Nesbitt, J.F.; Partain, W.L.

    1982-08-01

    The objective of this report is to evaluate the feasibility of designing a process canister that could also serve as a barrier canister. To do this a general set of performance criteria is assumed and several metal alloys having a high probability of demonstrating high corrosion resistance under repository conditions are evaluated in a qualitative design assessment. This assessment encompasses canister manufacture, the glass-filling process, interim storage, transportation, and to a limited extent, disposal in a repository. A series of scoping tests were carried out on two titanium alloys and Inconel 625 to determine if the high temperature inherent in the glass-fill processing would seriously affect either the strength or corrosion resistance of these metals. This is a process-related concern unique to the barrier canister concept. The material properties were affected by the heat treatments which simulated both the joule-heated glass melter process (titanium alloys and Inconel 625) and the in-can melter (ICM) process (Inconel 625). However, changes in the material properties were generally within 20% of the original specimens. Accelerated corrosion testing of the heat treated coupons in a highly oxygenated brine showed basic corrosion resistance of titanium grade 12 and Inconel 625 to compare favorably with that of the untreated coupons. The titanium grade 2 coupons experienced severe corrosion pitting. These corrosion tests were of a scoping nature and suitable primarily for the detection of gross sensitivity to the heat treatment inherent in the glass-fill process. They are only suggstive of repository performance since the tests do not adequately model the wide range of repository conditions that could conceivably occur.

  4. Boron neutron capture therapy applied to advanced breast cancers: Engineering simulation and feasibility study of the radiation treatment protocol

    NASA Astrophysics Data System (ADS)

    Sztejnberg Goncalves-Carralves, Manuel Leonardo

    This dissertation describes a novel Boron Neutron Capture Therapy (BNCT) application for the treatment of human epidermal growth factor receptor type 2 positive (HER2+) breast cancers. The original contribution of the dissertation is the development of the engineering simulation and the feasibility study of the radiation treatment protocol for this novel combination of BNCT and HER2+ breast cancer treatment. This new concept of BNCT, representing a radiation binary targeted treatment, consists of the combination of two approaches never used in a synergism before. This combination may offer realistic hope for relapsed and/or metastasized breast cancers. This treatment assumes that the boronated anti-HER2 monoclonal antibodies (MABs) are administrated to the patient and accumulate preferentially in the tumor. Then the tumor is destroyed when is exposed to neutron irradiation. Since the use of anti-HER2 MABs yields good and promising results, the proposed concept is expected to amplify the known effect and be considered as a possible additional treatment approach to the most severe breast cancers for patients with metastasized cancer for which the current protocol is not successful and for patients refusing to have the standard treatment protocol. This dissertation makes an original contribution with an integral numerical approach and proves feasible the combination of the aforementioned therapy and disease. With these goals, the dissertation describes the theoretical analysis of the proposed concept providing an integral engineering simulation study of the treatment protocol. An extensive analysis of the potential limitations, capabilities and optimization factors are well studied using simplified models, models based on real CT patients' images, cellular models, and Monte Carlo (MCNP5/X) transport codes. One of the outcomes of the integral dosimetry assessment originally developed for the proposed treatment of advanced breast cancers is the implementation of BNCT

  5. Milwaukee Estuary AOC

    EPA Pesticide Factsheets

    The rivers in the Milwaukee estuary in Wisconsin drain into Lake Michigan. Wastewater treatment plants and combined sewer overflows contribute pollution which affects fish and wildlife and recreation.

  6. Local Estuary Programs

    EPA Pesticide Factsheets

    This page provides information about Local Individual Estuary Programs including links to their NEP homepages, social media, Comprehensive Conservation and Management Plans, and state of the bay reports.

  7. Multi-lingual search engine to access PubMed monolingual subsets: a feasibility study.

    PubMed

    Darmoni, Stéfan J; Soualmia, Lina F; Griffon, Nicolas; Grosjean, Julien; Kerdelhué, Gaétan; Kergourlay, Ivan; Dahamna, Badisse

    2013-01-01

    PubMed contains many articles in languages other than English but it is difficult to find them using the English version of the Medical Subject Headings (MeSH) Thesaurus. The aim of this work is to propose a tool allowing access to a PubMed subset in one language, and to evaluate its performance. Translations of MeSH were enriched and gathered in the information system. PubMed subsets in main European languages were also added in our database, using a dedicated parser. The CISMeF generic semantic search engine was evaluated on the response time for simple queries. MeSH descriptors are currently available in 11 languages in the information system. All the 654,000 PubMed citations in French were integrated into CISMeF database. None of the response times exceed the threshold defined for usability (2 seconds). It is now possible to freely access biomedical literature in French using a tool in French; health professionals and lay people with a low English language may find it useful. It will be expended to several European languages: German, Spanish, Norwegian and Portuguese.

  8. Feasibility of ceramic-polymer composite cryogels as scaffolds for bone tissue engineering.

    PubMed

    Rodriguez-Lorenzo, Luis M; Saldaña, Laura; Benito-Garzón, Lorena; García-Carrodeguas, Raul; de Aza, Salvador; Vilaboa, Nuria; Román, Julio San

    2012-06-01

    The purpose of the current study was to investigate whether the cryopolymerization technique is capable of producing suitable scaffolds for bone tissue engineering. Cryopolymers made of 2-hydroxyethyl methacrylate and acrylic acid with (W1 and W20) and without (W0) wollastonite particles were prepared. The elastic modulus of the specimens rose one order of magnitude from W1 to W20. Total porosity reached 56% for W0, 72% for W1 and 36% for W20, with pore sizes of up to 2 mm, large interconnection sizes of up to 1 mm and small interconnection sizes of 50-80 µm on dry specimens. Cryogels swell up to 224 ± 17% for W0, 315 ± 18% for W1 and 231 ± 27% for W20 specimens, while maintaining the integrity of the bodies. Pore sizes > 5 mm can be observed for swollen specimens. The biocompatibility of the samples was tested using human mesenchymal stem cells isolated from bone marrow and adipose tissues. Both types of cells attached and grew on the three tested substrates, colonized their inner regions and organized an extracellular cell matrix. Fibronectin and osteopontin levels decreased in the media from cells cultured on W20 samples, likely due to increased binding on the ECM deposited by cells. The osteoprotegerin-to-receptor activator of nuclear factor-κB ligand secretion ratios increased with increasing wollastonite content. Altogether, these results indicate that an appropriate balance of surface properties and structure that favours stromal cell colonization in the porous cryogels can be achieved by modulating the amount of wollastonite.

  9. Estuary Data Mapper

    EPA Science Inventory

    The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary has three elements: an estuarine geo-referenced relational database, watershed GIS coverages, and tools to support decision-making. To facilita...

  10. Feasibility of silica-hybridized collagen hydrogels as three-dimensional cell matrices for hard tissue engineering.

    PubMed

    Yu, Hye-Sun; Lee, Eun-Jung; Seo, Seog-Jin; Knowles, Jonathan C; Kim, Hae-Won

    2015-09-01

    Exploiting hydrogels for the cultivation of stem cells, aiming to provide them with physico-chemical cues suitable for osteogenesis, is a critical demand for bone engineering. Here, we developed hybrid compositions of collagen and silica into hydrogels via a simple sol-gel process. The physico-chemical and mechanical properties, degradation behavior, and bone-bioactivity were characterized in-depth; furthermore, the in vitro mesenchymal stem cell growth and osteogenic differentiation behaviors within the 3D hybrid gel matrices were communicated for the first time. The hydrolyzed and condensed silica phase enabled chemical links with the collagen fibrils to form networked hybrid gels. The hybrid gels showed improved chemical stability and greater resistance to enzymatic degradation. The in vitro apatite-forming ability was enhanced by the hybrid composition. The viscoelastic mechanical properties of the hybrid gels were significantly improved in terms of the deformation resistance to an applied load and the modulus values under a dynamic oscillation. Mesenchymal stem cells adhered well to the hybrid networks and proliferated actively with substantial cytoskeletal extensions within the gel matrices. Of note, the hybrid gels substantially reduced the cell-mediated gel contraction behaviors, possibly due to the stiffer networks and higher resistance to cell-mediated degradation. Furthermore, the osteogenic differentiation of cells, including the expression of bone-associated genes and protein, was significantly upregulated within the hybrid gel matrices. Together with the physico-chemical and mechanical properties, the cellular behaviors observed within 3D gel matrices, being different from the previous approaches reported on 2D substrates, provide new information on the feasibility and usefulness of the silica-collagen system for stem cell culture and tissue engineering of hard tissues.

  11. Feasibility of Conducting J-2X Engine Testing at the Glenn Research Center Plum Brook Station B-2 Facility

    NASA Technical Reports Server (NTRS)

    Schafer, Charles F.; Cheston, Derrick J.; Worlund, Armis L.; Brown, James R.; Hooper, William G.; Monk, Jan C.; Winstead, Thomas W.

    2008-01-01

    A trade study of the feasibility of conducting J-2X testing in the Glenn Research Center (GRC) Plum Brook Station (PBS) B-2 facility was initiated in May 2006 with results available in October 2006. The Propulsion Test Integration Group (PTIG) led the study with support from Marshall Space Flight Center (MSFC) and Jacobs Sverdrup Engineering. The primary focus of the trade study was on facility design concepts and their capability to satisfy the J-2X altitude simulation test requirements. The propulsion systems tested in the B-2 facility were in the 30,000-pound (30K) thrust class. The J-2X thrust is approximately 10 times larger. Therefore, concepts significantly different from the current configuration are necessary for the diffuser, spray chamber subsystems, and cooling water. Steam exhaust condensation in the spray chamber is judged to be the key risk consideration relative to acceptable spray chamber pressure. Further assessment via computational fluid dynamics (CFD) and other simulation capabilities (e.g. methodology for anchoring predictions with actual test data and subscale testing to support investigation.

  12. New Bedford Harbor Superfund Project Acushnet River Estuary Engineering Feasibility Study of Dredging and Dredged Material Disposal Alternatives. Report 10. Evaluation of Dredging and Dredging Control Technologies

    DTIC Science & Technology

    1988-11-01

    concluded that the cutterhead showed very little resuspension when operated properly (Hayes, McLellan , and Truitt 1988). DIRECTION OF SWING TO PU M P...Illinois (Hayes, McLellan , and Truitt 1988). Controls for Sediment Resuspension 87. Careful planning, dredging techniques, and monitoring practices...Station, Vicksburg, MS. Hayes, D. F., McLellan , T. N., and Truitt, C. L. 1988. "Demonstrations of Innovative and Conventional Dredging Equipment at Calumet

  13. New Bedford Harbor Superfund Project, Acushnet River Estuary Engineering Feasibility Study of Dredging and Dredged Material Disposal Alternatives. Report 5. Evaluation of Leachate Quality

    DTIC Science & Technology

    1989-04-01

    Environmentally Transformed Polychlorinated Biphenyls by Alcaligenes eutrophus H850," Applied and Environmental Microbiology, Vol 53, No. 5, pp 1094-1102...Bopp, L. H. 1986. "Degradation of Highly Chlorinated PCBs by Pseudomonas Strain LB400," Journal of Industrial Microbiology, No. 1, pp 23-29. Brannon

  14. Feasibility study of using the RoboEarth cloud engine for rapid mapping and tracking with small unmanned aerial systems

    NASA Astrophysics Data System (ADS)

    Li-Chee-Ming, J.; Armenakis, C.

    2014-11-01

    This paper presents the ongoing development of a small unmanned aerial mapping system (sUAMS) that in the future will track its trajectory and perform 3D mapping in near-real time. As both mapping and tracking algorithms require powerful computational capabilities and large data storage facilities, we propose to use the RoboEarth Cloud Engine (RCE) to offload heavy computation and store data to secure computing environments in the cloud. While the RCE's capabilities have been demonstrated with terrestrial robots in indoor environments, this paper explores the feasibility of using the RCE in mapping and tracking applications in outdoor environments by small UAMS. The experiments presented in this work assess the data processing strategies and evaluate the attainable tracking and mapping accuracies using the data obtained by the sUAMS. Testing was performed with an Aeryon Scout quadcopter. It flew over York University, up to approximately 40 metres above the ground. The quadcopter was equipped with a single-frequency GPS receiver providing positioning to about 3 meter accuracies, an AHRS (Attitude and Heading Reference System) estimating the attitude to about 3 degrees, and an FPV (First Person Viewing) camera. Video images captured from the onboard camera were processed using VisualSFM and SURE, which are being reformed as an Application-as-a-Service via the RCE. The 3D virtual building model of York University was used as a known environment to georeference the point cloud generated from the sUAMS' sensor data. The estimated position and orientation parameters of the video camera show increases in accuracy when compared to the sUAMS' autopilot solution, derived from the onboard GPS and AHRS. The paper presents the proposed approach and the results, along with their accuracies.

  15. Climate Ready Estuaries Progress Reports

    EPA Pesticide Factsheets

    Climate Ready Estuaries has supported adaptation activities in National Estuary Programs since 2008. In 2012, the program partnered with 23 NEPs, completed a pilot project with water utilities, and held workshops. Download annual reports from 2009-2012.

  16. Feasibility study of a pressure-fed engine for a water recoverable space shuttle booster. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The activities leading to a tentative concept selection for a pressure-fed engine and propulsion support are outlined. Multiple engine concepts were evaluted through parallel engine major component and system analyses. Booster vehicle coordination, tradeoffs, and technology/development aspects are included. The concept selected for further evaluation has a regeneratively cooled combustion chamber and nozzle in conjuction with an impinging element injector. The propellants chosen are LOX/RP-1, and combustion stabilizing baffles are used to assure dynamic combustion stability.

  17. JT9D engine diagnostics. Task 2: Feasibility study of measuring in-service flight loads. [747 aircraft performance

    NASA Technical Reports Server (NTRS)

    Kafka, P. G.; Skibo, M. A.; White, J. L.

    1977-01-01

    The feasibility of measuring JT9D propulsion system flight inertia loads on a 747 airplane is studied. Flight loads background is discussed including the current status of 747/JT9D loads knowledge. An instrumentation and test plan is formulated for an airline-owned in-service airplane and the Boeing-owned RA001 test airplane. Technical and cost comparisons are made between these two options. An overall technical feasibility evaluation is made and a cost summary presented. Conclusions and recommendations are presented in regard to using existing inertia loads data versus conducting a flight test to measure inertia loads.

  18. Engineering and economic feasibility of using poultry litter as a fuel to generate electric power at Maryland`s Eastern Correctional Institute

    SciTech Connect

    Estomin, S.L.; Walters, G.; Prasad, A.; Ross, J.

    1998-02-16

    This report presents an analysis of the engineering, environmental, and economic feasibility of the Eastern Correctional Institute (ECI) meeting its electric power and thermal requirements by relying on poultry litter as a fuel. In addition to satisfying all or a portion of the utility requirements of ECI, a maximum/medium security prison located in Princess Anne, Maryland, the use of poultry litter as a fuel would reduce the amount of poultry waste currently used on the Eastern Shore as fertilizer. Based on the engineering and environmental assessments conducted, three alternative scenarios to satisfy ECI`s electric power supply and thermal requirements using poutlry litter as a fuel were developed. For all scenarios, as well as a base case defined by current operations at ECI, 20-year life-cycle costs were estimated based on projections of usage, capital costs, fuel costs, labor costs, and other relevant factors.

  19. Exploring the Feasibility of Developing an Automated Work Estimation System for the Air Force Communications Command Engineering and Installation Function.

    DTIC Science & Technology

    1983-09-01

    assistance ( RFTA ). The RFTA is processed through the re- quiring command’s channels to the Engineering and Instal- lation Center. The request is forwarded...to the appropriate branch and assigned to an engineer. The RFTA is the instru- ment that brings the experience and expertise of the commu...example, the RFTA is returned to the requiring command after completion, and the requiring command will incorporate the information provided into

  20. Visualizing feasible operating ranges within tissue engineering systems using a "windows of operation" approach: a perfusion-scaffold bioreactor case study.

    PubMed

    McCoy, Ryan J; O'Brien, Fergal J

    2012-12-01

    Tissue engineering approaches to developing functional substitutes are often highly complex, multivariate systems where many aspects of the biomaterials, bio-regulatory factors or cell sources may be controlled in an effort to enhance tissue formation. Furthermore, success is based on multiple performance criteria reflecting both the quantity and quality of the tissue produced. Managing the trade-offs between different performance criteria is a challenge. A "windows of operation" tool that graphically represents feasible operating spaces to achieve user-defined levels of performance has previously been described by researchers in the bio-processing industry. This paper demonstrates the value of "windows of operation" to the tissue engineering field using a perfusion-scaffold bioreactor system as a case study. In our laboratory, perfusion bioreactor systems are utilized in the context of bone tissue engineering to enhance the osteogenic differentiation of cell-seeded scaffolds. A key challenge of such perfusion bioreactor systems is to maximize the induction of osteogenesis but minimize cell detachment from the scaffold. Two key operating variables that influence these performance criteria are the mean scaffold pore size and flow-rate. Using cyclooxygenase-2 and osteopontin gene expression levels as surrogate indicators of osteogenesis, we employed the "windows of operation" methodology to rapidly identify feasible operating ranges for the mean scaffold pore size and flow-rate that achieved user-defined levels of performance for cell detachment and differentiation. Incorporation of such tools into the tissue engineer's armory will hopefully yield a greater understanding of the highly complex systems used and help aid decision making in future translation of products from the bench top to the market place.

  1. Feasibility of observing small differences in friction mean effective pressure between different lubricating oil formations using small, single-cylinder motored engine rig

    DOE PAGES

    Rohr, William F.; Nguyen, Ke; Bunting, Bruce G.; ...

    2015-09-01

    Here, the feasibility of using a motored single-cylinder 517 cc diesel engine to observe small frictional differences between oil formulations is investigated. Friction mean effective pressure (FMEP) is measured and compared for an SAE 10W-30 and an SAE 5W-20 oil in three stages of production: base oil, commercial oil without a friction and wear reducing additive, and fully formulated commercial oil. In addition, a commercial SAE 5W-30 engine oil is investigated. Friction mean effective pressure is plotted versus oil dynamic viscosity to compare the lubricant FMEP at a given viscosity. Linear regressions and average friction mean effective pressure are usedmore » as a secondary means of comparing FMEP for the various oil formulations. Differences between the oils are observed with the base oil having higher friction at a given viscosity but a lower average FMEP due to the temperature distribution of the test and lower viscosities reached by the base oil. The commercial oil is shown to have both a higher FMEP at a given viscosity and a higher average FMEP than the commercial oil without a friction and wear reducing additive. The increase in friction for the oil without a friction and wear reduction additive indicates that the operational regime of the engine may be out of the bounds of the optimal regime for the additive or that the additive is more optimized for wear reduction. Results show that it is feasible to observe small differences in FMEP between lubricating oil formulations using a small, single-cylinder motored engine.« less

  2. Feasibility of observing small differences in friction mean effective pressure between different lubricating oil formations using small, single-cylinder motored engine rig

    SciTech Connect

    Rohr, William F.; Nguyen, Ke; Bunting, Bruce G.; Qu, Jun

    2015-09-01

    Here, the feasibility of using a motored single-cylinder 517 cc diesel engine to observe small frictional differences between oil formulations is investigated. Friction mean effective pressure (FMEP) is measured and compared for an SAE 10W-30 and an SAE 5W-20 oil in three stages of production: base oil, commercial oil without a friction and wear reducing additive, and fully formulated commercial oil. In addition, a commercial SAE 5W-30 engine oil is investigated. Friction mean effective pressure is plotted versus oil dynamic viscosity to compare the lubricant FMEP at a given viscosity. Linear regressions and average friction mean effective pressure are used as a secondary means of comparing FMEP for the various oil formulations. Differences between the oils are observed with the base oil having higher friction at a given viscosity but a lower average FMEP due to the temperature distribution of the test and lower viscosities reached by the base oil. The commercial oil is shown to have both a higher FMEP at a given viscosity and a higher average FMEP than the commercial oil without a friction and wear reducing additive. The increase in friction for the oil without a friction and wear reduction additive indicates that the operational regime of the engine may be out of the bounds of the optimal regime for the additive or that the additive is more optimized for wear reduction. Results show that it is feasible to observe small differences in FMEP between lubricating oil formulations using a small, single-cylinder motored engine.

  3. A feasibility study of dynamic stress analysis inside a running internal combustion engine using synchrotron X-ray beams.

    PubMed

    Baimpas, Nikolaos; Drakopoulos, Michael; Connolley, Thomas; Song, Xu; Pandazaras, Costas; Korsunsky, Alexander M

    2013-03-01

    The present investigation establishes the feasibility of using synchrotron-generated X-ray beams for time-resolved in situ imaging and diffraction of the interior components of an internal combustion engine during its operation. The demonstration experiment was carried out on beamline I12 (JEEP) at Diamond Light Source, UK. The external hutch of the JEEP instrument is a large-scale engineering test bed for complex in situ processing and simulation experiments. The hutch incorporates a large capacity translation and rotation table and a selection of detectors for monochromatic and white-beam diffraction and imaging. These capabilities were used to record X-ray movies of a motorcycle internal combustion engine running at 1850 r.p.m. and to measure strain inside the connecting rod via stroboscopic X-ray diffraction measurement. The high penetrating ability and high flux of the X-ray beam at JEEP allowed the observation of inlet and outlet valve motion, as well as that of the piston, connecting rod and the timing chain within the engine. Finally, the dynamic internal strain within the moving connecting rod was evaluated with an accuracy of ~50 × 10(-6).

  4. A Feasibility Study of Expanding the F404 Aircraft Engine Repair Capability at the Aircraft Intermediate Maintenance Department

    DTIC Science & Technology

    1993-06-01

    Conduct a study to determine the feasibility and cost effectiveness of installing a blade tip grinder /balancing machine similar to the one discussed in...Capability .... ............. .. 54 3. Blade Tip Grinding and Balancing Capability 55 a. Blade Tip Grinding and Balancing Machine 56 vi b. Personnel...the Secretaries of the Military Departments to take specific actions designed to achieve the objectives of the DMRD without implementing the "single

  5. THE IMPACTS OF UPOGEBIA PUGETTENSIS POPULATIONS ON ORGANIC MATTER AND NUTRIENT CYCLING IN PACIFIC NORTHWEST ESTUARIES

    EPA Science Inventory

    The burrowing thalassinid shrimp, Upogebia pugettensis, is a major ecosystem engineering species of Pacific estuaries and can structure the physical, chemical, and biotic properties of benthic habitats. This study utilized incubations, benthic chambers and porewater peepers to q...

  6. Ecology of estuaries

    SciTech Connect

    Kennish, M.J. )

    1992-01-01

    Ecology of Estuaries: Anthropogenic Effects represents the most definitive and comprehensive source of reference information available on the human impact on estuarine ecosystems. The book discusses both acute and insidious pollution problems plaguing these coastal ecotones. It also provides a detailed examination of the deleterious and pervasive effects of human activities on biotic communities and sensitive habitat areas in estuaries. Specific areas covered include organic loading, oil pollution, polynuclear aromatic hydrocarbons, chlorinated hydrocarbons, heavy metals, dredging and dredge-spoil disposal, radionuclides, as well as other contaminants and processes. The diverse components of these anthropogenic influences are assembled in an organized framework and presented in a clear and concise style that will facilitate their understanding.

  7. 77 FR 24471 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-24

    ... Plan; and Feasibility of Alternatives to the Goat Rock State Beach Jetty for Managing Lagoon Water... is located at Goat Rock State Beach; the estuary extends from the mouth upstream approximately 10 to... `Feasibility of Alternatives to the Goat Rock State Beach Jetty for Managing Lagoon Water Surface...

  8. DC-9/JT8D refan, Phase 1. [technical and economic feasibility of retrofitting DC-9 aircraft with refan engine to achieve desired acoustic levels

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Analyses and design studies were conducted on the technical and economic feasibility of installing the JT8D-109 refan engine on the DC-9 aircraft. Design criteria included minimum change to the airframe to achieve desired acoustic levels. Several acoustic configurations were studied with two selected for detailed investigations. The minimum selected acoustic treatment configuration results in an estimated aircraft weight increase of 608 kg (1,342 lb) and the maximum selected acoustic treatment configuration results in an estimated aircraft weight increase of 809 kg (1,784 lb). The range loss for the minimum and maximum selected acoustic treatment configurations based on long range cruise at 10 668 m (35,000 ft) altitude with a typical payload of 6 804 kg (15,000 lb) amounts to 54 km (86 n. mi.) respectively. Estimated reduction in EPNL's for minimum selected treatment show 8 EPNdB at approach, 12 EPNdB for takeoff with power cutback, 15 EPNdB for takeoff without power cutback and 12 EPNdB for sideline using FAR Part 36. Little difference was estimated in EPNL between minimum and maximum treatments due to reduced performance of maximum treatment. No major technical problems were encountered in the study. The refan concept for the DC-9 appears technically feasible and economically viable at approximately $1,000,000 per airplane. An additional study of the installation of JT3D-9 refan engine on the DC-8-50/61 and DC-8-62/63 aircraft is included. Three levels of acoustic treatment were suggested for DC-8-50/61 and two levels for DC-8-62/63. Results indicate the DC-8 technically can be retrofitted with refan engines for approximately $2,500,000 per airplane.

  9. Ecology of estuaries

    SciTech Connect

    Kennish, M.J.

    1986-01-01

    This book is a summary of information available on estuarine ecology, that reviews concepts and problems of estuaries and assesses the value of these coastal systems. It investigates such topics as water circulation and mixing, trace elements, nutrients, organic matter, and sedimentary processes, with reviews on more than two decades of intense study. Chapters reflect contributions from a variety of interdisciplinary sciences including botany, chemistry, ecology, geology, physics, and zoology.

  10. Burrowing shrimp as foundation species in NE Pacific estuaries

    EPA Science Inventory

    My talk will be about the my research to characterize the role that burrowing shrimp play as foundation/engineering species in Pacific NW estuaries. My research has focused on measuring the abundance & distribution of two species (ghost shrimp & mud shrimp) at ecosystem scales, ...

  11. Feasibility study of air-breathing turbo-engines for horizontal take-off and landing space plane

    SciTech Connect

    Minoda, M.; Sakata, K.; Tamaki, T.; Saitoh, T.; Yasuda, A.

    1989-01-01

    Various concepts of air-breathing engines (ABEs) that could be used for a horizontal take-off and landing SSTO vehicle are investigated. The performances (with respect to thrust and the specific fuel consumption) of turboengines based on various technologies, including a turbojet with and without afterburner (TJ), turboramjet, and air-turbo-ram jet engines are compared. The mission capabilities of these ABEs for SSTO and TSTO vehicles is examined in terms of the ratio of the effective remaining weight (i.e., the weight on the orbit) to the take-off gross weight, using two-dimensional flight analysis. It was found that the dry TJ with the turbine inlet temperature 2000 C is one of the most promising candidates for the propulsion system of the SSTO vehicle, because of its small weight and high specific impulse. 6 refs.

  12. Early feasibility testing and engineering development of a sutureless beating heart connector for left ventricular assist devices.

    PubMed

    Koenig, Steven C; Jimenez, Jorge H; West, Seth D; Sobieski, Michael A; Choi, Young; Monreal, Gretel; Giridharan, Guruprasad A; Soucy, Kevin G; Slaughter, Mark S

    2014-01-01

    APK Advanced Medical Technologies (Atlanta, GA) is developing a sutureless beating heart (SBH) left ventricular assist device (LVAD) connector system consisting of anchoring titanium coil, titanium cannula with integrated silicone hemostatic valve, coring and delivery tool, and LVAD locking mechanism to facilitate LVAD inflow surgical procedures. Feasibility testing was completed in human cadavers (n = 4) under simulated normal and hypertensive conditions using saline to observe seal quality in degraded human tissue and assess anatomic fit; acutely in ischemic heart failure bovine model (n = 2) to investigate short-term performance and ease of use; and chronically for 30 days in healthy calves (n = 2) implanted with HeartWare HVAD to evaluate performance and biocompatibility. Complete hemostasis was achieved in human cadavers and animals at LV pressures up to 170 mm Hg. In animals, off-pump (no cardiopulmonary bypass) anchoring of the connector was accomplished in less than 1 minute with no residual bleeding after full delivery and locking of the LVAD; and implant of connector and LVAD were successfully completed in under 10 minutes with total procedure blood loss less than 100 ml. In chronic animals before necropsy, no signs of leakage or disruption at the attachment site were observed at systolic LV pressures >200 mm Hg.

  13. Early Feasibility Testing and Engineering Development of the Transapical Approach for the HeartWare MVAD Ventricular Assist System

    PubMed Central

    Tamez, Daniel; LaRose, Jeffrey A.; Shambaugh, Charles; Chorpenning, Katherine; Soucy, Kevin G; Sobieski, Michael A; Sherwood, Leslie; Giridharan, Guruprasad A; Monreal, Gretel; Koenig, Steven C; Slaughter, Mark S

    2014-01-01

    Implantation of ventricular assist devices (VADs) for treatment of end-stage heart failure (HF) falls decidedly short of clinical demand, which exceeds 100,000 HF patients per year. VAD implantation often requires major surgical intervention with associated risk of adverse events and long recovery periods. To address these limitations, HeartWare, Inc. (Miami Lakes, FL) has developed a platform of miniature ventricular devices with progressively reduced surgical invasiveness and innovative patient peripherals. One surgical implant concept is a transapical version of the miniaturized left ventricular assist device (MVAD). The HeartWare MVAD Pump® is a small, continuous flow, full-support device that has a displacement volume of 22mL. A new cannula configuration has been developed for transapical implantation, where the outflow cannula is positioned across the aortic valve. The two primary objectives for this feasibility study were to evaluate anatomic fit and surgical approach and efficacy of the transapical MVAD configuration. Anatomic fit and surgical approach were demonstrated using human cadavers (n=4). Efficacy was demonstrated in acute (n =2) and chronic (n = 1) bovine model experiments and assessed by improvements in hemodynamics, biocompatibility, flow dynamics, and histopathology. Potential advantages of the MVAD Pump include flow support in the same direction as the native ventricle, elimination of cardiopulmonary bypass, and minimally-invasive implantation. PMID:24399057

  14. Early feasibility testing and engineering development of the transapical approach for the HeartWare MVAD ventricular assist system.

    PubMed

    Tamez, Daniel; LaRose, Jeffrey A; Shambaugh, Charles; Chorpenning, Katherine; Soucy, Kevin G; Sobieski, Michael A; Sherwood, Leslie; Giridharan, Guruprasad A; Monreal, Gretel; Koenig, Steven C; Slaughter, Mark S

    2014-01-01

    Implantation of ventricular assist devices (VADs) for the treatment of end-stage heart failure (HF) falls decidedly short of clinical demand, which exceeds 100,000 HF patients per year. Ventricular assist device implantation often requires major surgical intervention with associated risk of adverse events and long recovery periods. To address these limitations, HeartWare, Inc. has developed a platform of miniature ventricular devices with progressively reduced surgical invasiveness and innovative patient peripherals. One surgical implant concept is a transapical version of the miniaturized left ventricular assist device (MVAD). The HeartWare MVAD Pump is a small, continuous-flow, full-support device that has a displacement volume of 22 ml. A new cannula configuration has been developed for transapical implantation, where the outflow cannula is positioned across the aortic valve. The two primary objectives for this feasibility study were to evaluate anatomic fit and surgical approach and efficacy of the transapical MVAD configuration. Anatomic fit and surgical approach were demonstrated using human cadavers (n = 4). Efficacy was demonstrated in acute (n = 2) and chronic (n = 1) bovine model experiments and assessed by improvements in hemodynamics, biocompatibility, flow dynamics, and histopathology. Potential advantages of the MVAD Pump include flow support in the same direction as the native ventricle, elimination of cardiopulmonary bypass, and minimally invasive implantation.

  15. Transient silencing of the KASII genes is feasible in Nicotiana benthamiana for metabolic engineering of wax ester composition

    PubMed Central

    Aslan, Selcuk; Hofvander, Per; Dutta, Paresh; Sitbon, Folke; Sun, Chuanxin

    2015-01-01

    The beta-ketoacyl-ACP synthase II (KASII) is an enzyme in fatty acid biosynthesis, catalyzing the elongation of 16:0-acyl carrier protein (ACP) to 18:0-ACP in plastids. Mutations in KASII genes in higher plants can lead to lethality, which makes it difficult to utilize the gene for lipid metabolic engineering. We demonstrated previously that transient expression of plastid-directed fatty acyl reductases and wax ester synthases could result in different compositions of wax esters. We hypothesized that changing the ratio between C16 (palmitoyl-compounds) and C18 (stearoyl-compounds) in the plastidic acyl-ACP pool by inhibition of KASII expression would change the yield and composition of wax esters via substrate preference of the introduced enzymes. Here, we report that transient inhibition of KASII expression by three different RNAi constructs in leaves of N. benthamiana results in almost complete inhibition of KASII expression. The transient RNAi approach led to a shift of carbon flux from a pool of C18 fatty acids to C16, which significantly increased wax ester production in AtFAR6-containing combinations. The results demonstrate that transient inhibition of KASII in vegetative tissues of higher plants enables metabolic studies towards industrial production of lipids such as wax esters with specific quality and composition. PMID:26063537

  16. Transient silencing of the KASII genes is feasible in Nicotiana benthamiana for metabolic engineering of wax ester composition.

    PubMed

    Aslan, Selcuk; Hofvander, Per; Dutta, Paresh; Sitbon, Folke; Sun, Chuanxin

    2015-06-11

    The beta-ketoacyl-ACP synthase II (KASII) is an enzyme in fatty acid biosynthesis, catalyzing the elongation of 16:0-acyl carrier protein (ACP) to 18:0-ACP in plastids. Mutations in KASII genes in higher plants can lead to lethality, which makes it difficult to utilize the gene for lipid metabolic engineering. We demonstrated previously that transient expression of plastid-directed fatty acyl reductases and wax ester synthases could result in different compositions of wax esters. We hypothesized that changing the ratio between C16 (palmitoyl-compounds) and C18 (stearoyl-compounds) in the plastidic acyl-ACP pool by inhibition of KASII expression would change the yield and composition of wax esters via substrate preference of the introduced enzymes. Here, we report that transient inhibition of KASII expression by three different RNAi constructs in leaves of N. benthamiana results in almost complete inhibition of KASII expression. The transient RNAi approach led to a shift of carbon flux from a pool of C18 fatty acids to C16, which significantly increased wax ester production in AtFAR6-containing combinations. The results demonstrate that transient inhibition of KASII in vegetative tissues of higher plants enables metabolic studies towards industrial production of lipids such as wax esters with specific quality and composition.

  17. Feasibility and limitations of the round robin test for assessment of in vitro chondrogenesis evaluation protocol in a tissue-engineered medical product.

    PubMed

    Yokoi, Masako; Hattori, Koji; Narikawa, Koichi; Ohgushi, Hajime; Tadokoro, Mika; Hoshi, Kazuto; Takato, Tsuyoshi; Myoui, Akira; Nanno, Katsuhiko; Kato, Yukio; Kanawa, Masami; Sugawara, Katsura; Kobo, Tomoko; Ushida, Takashi

    2012-07-01

    Tissue-engineered medical products (TEMPs) should be evaluated before implantation. Therefore, it is indispensable to establish evaluation protocols in regenerative medicine. Whether or not such evaluation protocols are reasonable is generally verified through a 'round robin' test. However, the round robin test for TEMPs intrinsically includes a deficiency, because 'identical' specimens can not be prepared for TEMPs. The aim of the study was to assess the feasibility and limitations of the round robin test for TEMPs by using a prepared evaluation protocol. We adopted tissue-engineered cartilage constructs as delivered specimens and a protocol of measuring sGAG content as an evaluation protocol proposed to ISO TC150/SC7, which is an invasive, but usually applied, method, although non-invasive methods are keenly required in evaluating TEMPs. The results showed that: (a) the coefficient of variation (CV) of the measured sGAG contents in intralaboratory tests was ~5% at most; (b) the CV of sGAG content in the scheme where each participating laboratory measured different constructs was comparable with that in the scheme where each participating laboratory measured one half of a construct along with the organizing laboratory; (c) the CV caused by factors other than the specimen was ~15%, comparable to that in reproducible experiments in biomedical fields. Based on these results, the study concludes that a round robin test for a TEMP could be valuable, under the condition that the delivered TEMPs are sufficiently reproducible so that the CV of the measured values is < 5% in the organizing laboratory.

  18. First percutaneous implantation of a completely tissue-engineered self-expanding pulmonary heart valve prosthesis using a newly developed delivery system: a feasibility study in sheep.

    PubMed

    Spriestersbach, Hendrik; Prudlo, Antonia; Bartosch, Marco; Sanders, Bart; Radtke, Torben; Baaijens, Frank P T; Hoerstrup, Simon P; Berger, Felix; Schmitt, Boris

    2017-01-01

    In a European consortium, a decellularized tissue-engineered heart valve (dTEHV) based on vessel-derived cells, a fast-degrading scaffold and a self-expanding stent has been developed. The aim of this study was to demonstrate that percutaneous delivery is feasible. To implant this valve prosthesis transcutaneously into pulmonary position, a catheter delivery system was designed and custom made. Three sheep underwent transjugular prototype implantation. Intracardiac echocardiography (ICE), angiography and computed tomography (CT) were applied to assess the position, morphology, function and dimensions of the stented dTEHV. One animal was killed 3 h after implantation and two animals were followed up for 12 weeks. Explanted valves were analyzed macroscopically and microscopically. In all animals, the percutaneous implantation of the stented dTEHV was successful. The prototype delivery system worked at first attempt in all animals. In the first implantation a 22 F system was used: the valve was slightly damaged during crimping. Loading was difficult due to valve-catheter mismatch in volume. In the second and third implantation a 26 F system was used: the valves fitted adequately and stayed intact. Following implantation, these two valves showed moderate regurgitation due to insufficient coaptation. During follow-up, regurgitation increased due to shortened leaflets. At explantation, macroscopic and microscopic analysis confirmed the second and third valve to be intact. Histology revealed autologous recellularization of the decellularized valve after 12 weeks in vivo. It was demonstrated that completely in vitro tissue-engineered heart valves are thin and stable enough to be crimped and implanted transvenously into pulmonary position.

  19. Geochemistry of the Amazon Estuary

    USGS Publications Warehouse

    Smoak, Joseph M.; Krest, James M.; Swarzenski, Peter W

    2006-01-01

    The Amazon River supplies more freshwater to the ocean than any other river in the world. This enormous volume of freshwater forces the estuarine mixing out of the river channel and onto the continental shelf. On the continental shelf, the estuarine mixing occurs in a very dynamic environment unlike that of a typical estuary. The tides, the wind, and the boundary current that sweeps the continental shelf have a pronounced influence on the chemical and biological processes occurring within the estuary. The dynamic environment, along with the enormous supply of water, solutes and particles makes the Amazon estuary unique. This chapter describes the unique features of the Amazon estuary and how these features influence the processes occurring within the estuary. Examined are the supply and cycling of major and minor elements, and the use of naturally occurring radionuclides to trace processes including water movement, scavenging, sediment-water interaction, and sediment accumulation rates. The biogeochemical cycling of carbon, nitrogen, and phosphorus, and the significances of the Amazon estuary in the global mass balance of these elements are examined.

  20. Dispersion in alluvial convergent estuaries

    NASA Astrophysics Data System (ADS)

    Zhang, Zhilin; Savenije, Hubert H. G.

    2016-04-01

    The Van der Burgh's equation for longitudinal effective dispersion is a purely empirical method with practical implications. Its application to the effective tidal average dispersion under equilibrium conditions appears to have excellent performance in a wide range of alluvial estuaries. In this research, we try to find out the physical meaning of Van der Burgh's coefficient. Researchers like MacCready, Fischer, Kuijper, Hansen and Rattray have tried to split up dispersion into its constituents which did not do much to explain overall behaviour. In addition, traditional literature on dispersion is mostly related to flumes with constant cross-section. This research is about understanding the Van der Burgh's coefficient facing the fact that natural estuaries have exponentially varying cross-section. The objective is to derive a simple 1-D model considering both longitudinal and lateral mixing processes based on field observations (theoretical derivation). To that effect, we connect dispersion with salinity using the salt balance equation. Then we calculate the salinity along the longitudinal direction and compare it to the observed salinity. Calibrated dispersion coefficients in a range of estuaries are then compared with new expressions for the Van der Burgh's coefficient K and it is analysed if K varies from estuary to estuary. The set of reliable data used will be from estuaries: Kurau, Perak, Bernam, Selangor, Muar, Endau, Maputo, Thames, Corantijn, Sinnamary, Mae Klong, Lalang, Limpopo, Tha Chin, Chao Phraya, Edisto and Elbe.

  1. Technical and Engineering Feasibility Study of the Vitrification of Plutonium-Bearing Sludges at the Krasnoyarsk Mining and Chemical Combine by Means of Microwave Heating

    SciTech Connect

    Revenko, Y.A.; Kudinov, K.G.; Tretyakov, A.A.; Vassilyev, A.V.; Borisov, G.B.; Nazarov, A.V.; Aloy, A.S.; Shvedov, A.A.; Gusakov, B.V.; Jardine, L.J.

    2000-03-03

    This engineering feasibility study compared three possible technical options and their economic viability of processing plutonium-bearing sludges containing 0.6 MT of weapons-grade Pu accumulated at the Mining and Chemical Combine (MCC) at Krasnoyarsk. In Option 1, the baseline, the sludges are processed by extraction and purification of plutonium for storage using existing technologies, and the non-soluble radioactive residues generated in these processes undergo subsequent solidification by cementation. Options 2 and 3 involve the direct immobilization of plutonium-bearing sludges into a solid matrix (without any Pu extraction) using a microwave solidification process in a metal crucible to produce a glass, which is boron-silicate in Option 2 and phosphate glass in Option 3. In all three options, the solid radioactive waste end products will be placed in storage for eventual geologic disposal. Immobilization of residual plutonium into glass-like matrices provides both safer storage over the lifetime of the radionuclides and greater security against unauthorized access to stored materials than does the extraction and concentration of PuO{sub 2}, supporting our efforts toward non-proliferation of fissile materials. Although immobilization in boron-silicate glass appears now to be marginally preferable compared to the phosphate glass option, a number of technical issues remain to be assessed by further study to determine the preferable immobilization option.

  2. Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection

    EPA Science Inventory

    We examined the role of the ocean –estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

  3. Dissolved oxygen in two Oregon estuaries: Importance of the ocean-estuary connection - March 2011

    EPA Science Inventory

    We examined the role of the ocean–estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO w...

  4. Dissolved oxygen in two Oregon estuaries: Importance of the ocean-estuary connection

    EPA Science Inventory

    We examined the role of the ocean –estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

  5. Downloading and Installing Estuary Data Mapper (EDM)

    EPA Pesticide Factsheets

    Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

  6. About the Climate Ready Estuaries Program

    EPA Pesticide Factsheets

    The Climate Ready Estuaries program is a partnership between EPA and the National Estuary Programs to address climate change in coastal areas. It has helped coastal communities prepare for climate change since 2008.

  7. Frequent Questions about Estuary Data Mapper (EDM)

    EPA Pesticide Factsheets

    Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

  8. SSPA Equipment Engineering Feasibility Report

    SciTech Connect

    N.E. Woolstenhulme; C.R. Clark

    2011-09-01

    In response to a demanding reactor conversion schedule, construction of the Shielded Sample Preparation Area (SSPA) was initiated in 2010 to augment the existing capabilities of the Hot Fuel Examination Facility (HFEF). While HFEF is and will remain the workhorse for post irradiation sample preparation, there is currently a large backlog of Post-Irradiation Examination (PIE) experiments caused by numerous competing projects (this backlog is expected to continue for the foreseeable future). HFEF, in its present configuration also lacks the ability to prepare samples suitable for several of the tests that have been identified for the successful conclusion of the RERTR program; these samples require fine detail machining of irradiated fuel plates.

  9. KNOW YOUR ESTUARY: THE WATER THROUGH TIME

    EPA Science Inventory

    This presentation will focus on historical changes in water quality in the Yaquina Estuary, Oregon, and factors which influence water quality within this estuary. Topics presented will include the importance of ocean conditions on water quality in the estuary; historical changes...

  10. 78 FR 57624 - Availability of a Draft Integrated Feasibility Report (Feasibility Study/Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ... Feasibility Report (IFR), which includes a Draft Feasibility Study (FS) and Environmental Impact Statement... Department of the Army; Corps of Engineers Availability of a Draft Integrated Feasibility Report (Feasibility Study/Environmental Impact Statement/Environmental Impact Report), Los Angeles River...

  11. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring and Evaluation FY08 Annual Report.

    SciTech Connect

    Johnson, GE; Diefenderfer, HL

    2008-09-29

    The Estuary/Ocean Subgroup (EOS) is part of the research, monitoring, and evaluation (RME) effort that the Action Agencies (Bonneville Power Administration (BPA), U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In fiscal year 2008 (FY08), EOS project accomplishments included (1) subgroup meetings; (2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; (3) project management via BPA's project tracking system, Pisces; (4) quarterly project status reports; and (5) a major revision to the Estuary RME document and its subsequent regional release (new version January 2008). Many of the estuary RME recommendations in this document were incorporated into the Biological Opinion on FCRPS operations (May 2008). In summary, the FY08 EOS project resulted in expanded, substantive coordination with other regional RME forums, a new version of the federal Estuary RME program document, and implementation coordination. This annual report is a FY08 deliverable for the project titled Facilitation of the Estuary/Ocean Subgroup.

  12. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY08 Annual Report

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2008-09-29

    The Estuary/Ocean Subgroup (EOS) is part of the research, monitoring, and evaluation (RME) effort that the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In fiscal year 2008 (FY08), EOS project accomplishments included 1) subgroup meetings; 2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; 3) project management via the project tracking system, Pisces; 4) quarterly project status reports; and 5) a major revision to the Estuary RME document and its subsequent regional release (new version January 2008). Many of the estuary RME recommendations in this document were incorporated into the Biological Opinion on hydrosystem operations (May 2008). In summary, the FY08 EOS project resulted in expanded, substantive coordination with other regional RME forums, a new version of the federal Estuary RME program document, and implementation coordination. This annual report is a FY08 deliverable for the project titled Facilitation of the Estuary/Ocean Subgroup.

  13. Valuing environmental water pulses into the Incomati estuary: Key to achieving equitable and sustainable utilisation of transboundary waters

    NASA Astrophysics Data System (ADS)

    Sengo, D. José; Kachapila, Albert; Zaag, Pieter van der; Mul, Marloes; Nkomo, Sakhiwe

    Upstream developments in the Incomati river basin, shared by South Africa, Swaziland and Mozambique, have altered downstream flows significantly. The frequency of small floods into the estuary has been reduced dramatically. This change in the flow regime has impacted on the state of the environment downstream, and the Incomati estuary in particular. The estuary requires fresh water pulses that naturally occur, and the resulting seasonal flooding of the plains. Resource-poor rural households depend on the goods and services that the estuary and flood plains provide such as wood, charcoal, building materials, fish and shrimp, wetland farming, and tourism. Alteration of the flow regime into the estuary has a negative impact on the state of the environment and hence on the goods and services the estuary yields; a phenomenon the people living near the estuary are keenly aware of. The article estimates the value of the goods and services that the estuary currently provides, that is under the conditions of a changed flow regime. A linear relationship is then assumed between fresh water pulses into the estuary and the goods and services it provides, so that the order of magnitude of the economic value of fresh water pulses into the estuary may be approximated. Various development scenarios in the Incomati basin are then considered, that have different upstream and downstream impacts on water availability, and the basin-wide benefits and costs are compared. The paper concludes that the principle of sharing the benefits derived from the water resources, rather than the water itself, as proposed by authors such as [Sadoff, C.W., Grey, D., 2002. Beyond the river: the benefits of cooperation on international rivers. Water Policy 4, 389-403], may be a feasible approach only if the less tangible benefits and functions, especially those of the environment, are assigned an appropriate value and corresponding priority.

  14. Food Webs in an Estuary.

    ERIC Educational Resources Information Center

    Dunne, Barbara B.

    The Maryland Marine Science Education Project has produced a series of mini-units in marine science education for the junior high/middle school classroom. This unit focuses on food chains in an estuary. Although the unit specifically treats the Chesapeake Bay, it may be adapted for use with similar estuarine systems. In addition, the unit may be…

  15. Simulated Sampling of Estuary Plankton

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.; Jenkins, Deborah Bainer

    2009-01-01

    To find out about the microscopic life in the valuable estuary environment, it is usually necessary to be near the water. This dry lab offers an alternative, using authentic data and a simulation of plankton sampling. From the types of organisms found in the sample, middle school students can infer relationships in the biological and physical…

  16. NTRE extended life feasibility assessment

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Results of a feasibility analysis of a long life, reusable nuclear thermal rocket engine are presented in text and graph form. Two engine/reactor concepts are addressed: the Particle Bed Reactor (PBR) design and the Commonwealth of Independent States (CIS) concept. Engine design, integration, reliability, and safety are addressed by various members of the NTRE team from Aerojet Propulsion Division, Energopool (Russia), and Babcock & Wilcox.

  17. Feasibility study of an Integrated Program for Aerospace-vehicle Design (IPAD) system. Volume 3: Engineering creative/evaluation processes, phase 1, task 2

    NASA Technical Reports Server (NTRS)

    Garrocq, C. A.; Hosek, J. J.

    1973-01-01

    A series of functional flow charts are considered that were developed to properly identify and record the degree of participation of the disciplines considered in this feasibility study and the type of data required in the design process.

  18. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring, and Evaluation, FY06 Annual Report

    SciTech Connect

    Johnson, Gary E.

    2006-10-03

    This annual report is a deliverable for fiscal year 2006 (FY06) for Project 2002-077-00, Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to the 2000 and 2004 Biological Opinions on operation of the Federal Columbia River Power System. The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates implementation of the Estuary RME Plan. In FY06, EOS project accomplishments included: 1) subgroup meetings; 2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; 3) project management via the project tracking system, PISCES; 4) quarterly project status reports; and 5) a major revision to the Estuary RME Plan (new version May 2006) based on comments by EOS members, the Independent Scientific Review Panel, and other reviewers. In the context of uncertainty about the direction of the federal RME due to litigation on the FCRPS Biological Opinion, FY06 activities for the EOS project resulted in expanded substantive coordination with other regional RME forums, project tracking infrastructure, and a new version of the Estuary RME Plan.

  19. 75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-21

    ...: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice; request for comments. SUMMARY: NOAA, on behalf of the interagency Estuary Habitat... received by July 21, 2010. ADDRESSES: Send comments to Estuary Habitat Restoration Strategy, NOAA...

  20. DENSITY-DEPENDENT IMPACTS OF BIOIRRIGATION BY THE BURROWING SHRIMP UPOGEBIA PUGETTENSIS ON BENTHIC FLUXES AND POREWATER SOLUTE DISTRIBUTIONS IN PACIFIC NORTHWEST ESTUARIES

    EPA Science Inventory

    Burrowing thalassinid shrimp are major ecosystem engineering species of Pacific estuaries and can structure the physical, chemical, and biotic properties of sediments. Feeding and burrow irrigation by benthic organisms can increase the remineralization rates of organic material (...

  1. MAPPING BATHYMETRY AND BOTTOM TYPE IN A SHALLOW ESTUARY

    EPA Science Inventory

    Bathymetry and bottom type are important in characterizing estuaries and their ecology but hard to map, especially in shallow estuaries. Acoustic backscattering was used to remotely sense these properties in the shallow Slocums River Estuary of Massachusetts. Acoustic pulses were...

  2. Comparison of Nutrient Drivers and Response Metrics in Oregon Estuaries

    EPA Science Inventory

    With the goal of assessing sensitivity to nutrient enrichment, we present a cross-estuary comparison of nutrient sources, levels, and biological responses (phytoplankton and macroalgae) for thirteen Oregon estuaries. Nitrogen levels in the upstream portions of the estuaries are ...

  3. Tidal wetland conservation and restoration for flood mitigation in estuaries and deltas: examples and global potential

    NASA Astrophysics Data System (ADS)

    Temmerman, Stijn; Smolders, Sven; Stark, Jeroen; meire, patrick

    2014-05-01

    estuaries and deltas worldwide. We discuss the societal benefits and drawbacks of wetland creation for flood defense, and provide an estimation of where on Earth this approach could be feasible. This shows that many of the largest urban populations that are at risk from coastal flooding, are located in large deltas and estuaries, such as in Southeast Asia, North America and Europe. We argue that many of these vulnerable areas are potentially well suited to include wetland conservation and restoration as an essential part of adaptation and mitigation strategies against storm surge flood risks. References: Temmerman S., Meire P., Bouma T.J., Herman P.M.J., Ysebaert T., De Vriend H.J. (2013) Ecosystem-based coastal defense in the face of global change. Nature, 504, P. 79-83, doi:10.1038/nature12859.

  4. Case Study Application of the Biodiversity Security Index to Ranking Feasibility Studies for Ecosystem Restoration Projects of the U.S. Army Corps of Engineers

    DTIC Science & Technology

    2016-04-01

    Engineers. The sites were selected to represent a wide range of geographic, ecological , and engineering attributes. The BSI application method...51 Accuracy of Ecological and Management Data... ecological elements into the value it represents and is broadly applicable across Corps projects and programs. This is in sharp contrast with metrics now

  5. Protocols for Monitoring Habitat Restoration Projects in the Lower Columbia River and Estuary

    SciTech Connect

    Roegner, G. Curtis; Diefenderfer, Heida L.; Borde, Amy B.; Thom, Ronald M.; Dawley, Earl M.; Whiting, Allan H.; Zimmerman, Shon A.; Johnson, Gary E.

    2008-04-25

    Protocols for monitoring salmon habitat restoration projects are essential for the U.S. Army Corps of Engineers' environmental efforts in the Columbia River estuary. This manual provides state-of-the science data collection and analysis methods for landscape features, water quality, and fish species composition, among others.

  6. Carbon dioxide emissions from Indian monsoonal estuaries

    NASA Astrophysics Data System (ADS)

    Sarma Vedula, VSS

    2012-07-01

    The oceans act as a net sink for atmospheric CO2, however, the role of coastal bodies on global CO2 fluxes remains unclear due to lack of data. The estimated absorption of CO2 from the continental shelves, with limited data, is 0.22 to 1.0 PgC/y, and of CO2 emission by estuaries to the atmosphere is 0.27 PgC/y. The estimates from the estuaries suffer from large uncertainties due to large variability and lack of systematic data collection. It is especially true for Southeast Asian estuaries as the biogeochemical cycling of material are different due to high atmospheric temperature, seasonality driven by monsoons, seasonal discharge etc. In order to quantify CO2 emissions from the Indian estuaries, samples were collected at 27 estuaries all along the Indian coast during discharge wet and dry periods. The emissions of CO2 to the atmosphere from Indian estuaries were 4-5 times higher during wet than dry period. The pCO2 ranged between ~300 and 18492 microatm which were within the range of world estuaries. The mean pCO2 and particulate organic carbon (POC) showed positive relation with rate of discharge suggesting availability of high quantities of organic matter that led to enhanced microbial decomposition. The annual CO2 fluxes from the Indian estuaries, together with dry period data available in the literature, amounts to 1.92 TgC which is >10 times less than that from the European estuaries. The low CO2 fluxes from the Indian estuaries are attributed to low flushing rates and less human settlements along the banks of the Indian estuaries.

  7. Towards medium-term (order of months) morphodynamic modelling of the Teign estuary, UK

    NASA Astrophysics Data System (ADS)

    Bernardes, Marcos E. C.; Davidson, Mark A.; Dyer, Keith R.; George, Ken J.

    2006-07-01

    The main objective of this paper is to address the principal mechanisms involved in the medium-term (order of months to years) morphodynamic evolution of estuaries through the application of a process-based numerical modelling. The Teign estuary (Teignmouth, UK) is the selected site. The system is forced by the macrotidal semi-diurnal tide in the English Channel and is perturbed to a minor extent by high river discharge events (freshets). Although waves have a definite influence on the adjacent coastal area, Wells (Teignmouth Quay Development Environmental Statement: Changes to Physical Processes. Report R.984c:140. ABP Marine Environmental Research Ltd., Southampton, 2002b) suggested that swell waves do not enter the estuary. Hence, wave effects are neglected in this study, as only tides and the river discharge are taken into account. The sediment grain size is highly variable, but mainly sandy. Within the frame of the COAST3D project ( http://www.hrwallingford.co.uk/projects/COAST3D ), four bathymetric surveys of the adjacent coastal area were carried out at a nearly weekly intervals. The outer estuary and the adjacent coastal area were also surveyed every 6 months as part of the COASTVIEW project ( http://thecoastviewproject.org ). Based on these data and on continuously measured parameters, such as water level, waves, wind and river discharge, numerical modelling of the morphodynamic processes can be tested. To replicate the morphological changes in the medium-term within a feasible simulation time, forcing conditions are reduced through the use of an input reduction method (called ensemble technique). In this study, simulations are based on the coupling between Telemac-2D and its non-cohesive sediment

  8. AFS Estuaries Section - A Successful Partnership

    EPA Science Inventory

    The Estuaries Section of the American Fisheries Society offers travel awards to students in support of their attendance and presentations at the AFS meeting. Since 2007, the Southern Association of Marine Laboratories has partnered with the Estuaries Section to sponsor two stude...

  9. Dissolved Oxygen Data for Coos Estuary (Oregon)

    EPA Science Inventory

    The purpose of this product is the transmittal of dissolved oxygen data collected in the Coos Estuary, Oregon to Ms. Molly O'Neill (University of Oregon), for use in her studies on the factors influencing spatial and temporal patterns in dissolved oxygen in this estuary. These d...

  10. Country-wide assessment of estuary health: An approach for integrating pressures and ecosystem response in a data limited environment

    NASA Astrophysics Data System (ADS)

    Van Niekerk, L.; Adams, J. B.; Bate, G. C.; Forbes, A. T.; Forbes, N. T.; Huizinga, P.; Lamberth, S. J.; MacKay, C. F.; Petersen, C.; Taljaard, S.; Weerts, S. P.; Whitfield, A. K.; Wooldridge, T. H.

    2013-09-01

    Population and development pressures increase the need for proactive strategic management on a regional or country-wide scale - reactively protecting ecosystems on an estuary-by-estuary basis against multiple pressures is 'resource hungry' and not feasible. Proactive management requires a strategic assessment of health so that the most suitable return on investment can be made. A country-wide assessment of the nearly 300 functional South African estuaries examined both key pressures (freshwater inflow modification, water quality, artificial breaching of temporarily open/closed systems, habitat modification and exploitation of living resources) and health state. The method used to assess the type and level of the different pressures, as well as the ecological health status of a large number of estuaries in a data limited environment is described in this paper. Key pressures and the ecological condition of estuaries on a national scale are summarised. The template may also be used to provide guidance to coastal researchers attempting to inform management in other developing countries. The assessment was primarily aimed at decision makers both inside and outside the biodiversity sector. A key starting point was to delineate spatially the estuary functional zone (area) for every system. In addition, available data on pressures impacting estuaries on a national scale were collated. A desktop national health assessment, based on an Estuarine Health Index developed for South African ecological water requirement studies, was then applied systematically. National experts, all familiar with the index evaluated the estuaries in their region. Individual estuarine health assessment scores were then translated into health categories that reflect the overall status of South Africa's estuaries. The results showed that estuaries in the warm-temperate biogeographical zone are healthier than those in the cool-temperate and subtropical zones, largely reflecting the country

  11. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY10 Annual Report

    SciTech Connect

    Johnson, Gary E.

    2010-10-26

    The Estuary/Ocean Subgroup (EOS) is part of the research, monitoring, and evaluation (RME) effort that the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. The EOS is one of multiple work groups in the federal research, monitoring, and evaluation (RME) effort developed in response to responsibilities arising from the Endangered Species Act as a result of operation of the FCRPS. The EOS is tasked by NOAA Fisheries and the Action Agencies to design and coordinate implementation of the federal RME plan for the lower Columbia River and estuary, including the plume.

  12. United States Air Force 611th Air Support Group/Civil Engineering Squadron Elmendorf AFB, Alaska. Remedial investigation and feasibility study. Bullen Point Radar Installation, Alaska. Final report

    SciTech Connect

    Karmi, S.

    1996-03-18

    The United States Air Force (Air Force) has prepared this Remedial investigation/Feasibility Study (RI/FS) report as part of the Installation Restoration Program (IRP) to present results of RI/FS activities at five sites at the Bullen Point radar installation. The IRP provides for investigating, quantifying, and remediating environmental contamination from past waste management activities at Air Force installations throughout the United States.

  13. D-21B RBCC Modification Feasibility Study

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This report presents a feasibility study on the modifications required to re-engine the Lockheed D-21 Drone for use as a NASA RBCC engine. An introduction, background information, engine configuration and performance, propulsion system integration, loads/thermal analysis, avionics/systems, flight test results, costs and work schedule, and some conclusions are presented.

  14. Green Engineering

    EPA Pesticide Factsheets

    Green Engineering is the design, commercialization and use of processes and products that are feasible and economical while reducing the generation of pollution at the source and minimizing the risk to human health and the environment.

  15. Columbia Estuary Ecosystem Restoration Program: Restoration Design Challenges for Topographic Mounds, Channel Outlets, and Reed Canarygrass

    SciTech Connect

    Diefenderfer, Heida L.; Borde, Amy B.; Sinks, Ian A.; Cullinan, Valerie I.; Zimmerman, Shon A.

    2016-08-31

    The purpose of this study was to provide science-based information to practitioners and managers of restoration projects in the Columbia Estuary Ecosystem Restoration Program (CEERP) regarding aspects of restoration techniques that currently pose known challenges and uncertainties. The CEERP is a program of the Bonneville Power Administration (BPA) and the U.S. Army Corps of Engineers (Corps), Portland District, in collaboration with the National Marine Fisheries Service and five estuary sponsors implementing restoration. The estuary sponsors are Columbia Land Trust, Columbia River Estuary Study Taskforce, Cowlitz Tribe, Lower Columbia Estuary Partnership, and Washington Department of Fish and Wildlife. The scope of the research conducted during federal fiscal year 2015 included three aspects of hydrologic reconnection that were selected based on available scientific information and feedback from restoration practitioners during project reviews: the design of mounds (also called hummocks, peninsulas, or berms); the control of reed canarygrass (Phalaris arundinaceae); and aspects of channel network design related to habitat connectivity for juvenile salmonids.

  16. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring and Evaluation - FY07 Annual Report.

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2007-10-10

    This annual report is a deliverable for fiscal year 2007 (FY07) for Project 2002-077-00, Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort of the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to responsibilities arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In FY07, EOS project accomplishments included (1) subgroup meetings; (2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; (3) project management via the project tracking system, PISCES; (4) quarterly project status reports; and (5) a major revision to the Estuary RME Plan (new version September 2007) based on comments by EOS members and invited reviewers.

  17. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring, and Evaluation, FY07 Annual Report

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2007-10-10

    This annual report is a deliverable for fiscal year 2007 (FY07) for Project 2002-077-00, Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to responsibilities arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In FY07, EOS project accomplishments included 1) subgroup meetings; 2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; 3) project management via the project tracking system, PISCES; 4) quarterly project status reports; and 5) a major revision to the Estuary RME Plan (new version September 2007) based on comments by EOS members and invited reviewers.

  18. Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection - May 16, 2011

    EPA Science Inventory

    We examined the role of the ocean –estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

  19. United States Air Force 611th Air Support Group Civil Engineering Squadron, Elmendorf AFB, Alaska. Remedial investigation and feasibility study Point Lay Radar Installation, Alaska. Final report

    SciTech Connect

    Karmi, S.

    1996-03-04

    The United States Air Force (Air Force) has prepared this Remedial Investigation/Feasibility Study (RI/FS) report to present the results of RI/FS activities at four sites located at the Point Lay radar installation. The remedial investigation (RI) field activities were conducted at the Point Lay radar installation during the summer of 1993. The four sites at Point Lay were investigated because they were suspected of being contaminated with hazardous substances. RI activities were conducted using methods and procedures specified in the RI/FS Work Plan, Sampling and Analysis Plan (SAP), and Health and Safety Plan.

  20. Fluidization of mud in estuaries

    NASA Astrophysics Data System (ADS)

    Wolanski, Eric; Chappell, John; Ridd, Peter; Vertessy, Rob

    1988-03-01

    The South Alligator River, located in the Northern Territory, Australia, is a macrotidal estuary with suspended sediment concentration values reaching 10 g 1-1 In September 1986, in the dry season, the estuary was well mixed in temperature and salinity. While the vertical gradients in suspended sediment concentration were small at flood tides, for most of the ebb tide duration a lutocline separated a clear upper layer from an extremely turbid bottom layer, both layers being of comparable thickness. The tidal evolution of the suspended sediment concentration is consistent with that computed by a numerical model based on the equation of conservation of mass of suspended sediment. In this model, sediment is entrained from the bottom and mixed vertically upward by eddy diffusion, but through a Richardson number dependence, sediment-induced buoyancy effects inhibit vertical mixing. The final depth of the turbid layer can be readily estimated analytically as a result of a balance between the rate of kinetic energy input and the buoyancy flux determined by the particle fall velocity. The presence of a lutocline helps form mud banks on the inner side of a meander.

  1. Collaborative Potential between National Estuary Programs ...

    EPA Pesticide Factsheets

    Estuaries are among the most productive ecosystems in the world, providing unique habitat for freshwater and marine species as well as valuable social and economic benefits. The wealth of ecosystem goods and services from estuaries has led to growth and development of human communities in adjacent areas and an increase in human activities that can adversely affect water quality and critical habitat. Managing for sustainable estuaries requires a balance of environmental concerns with community social and economic values. This has created an opportunity to leverage Environmental Protection Agency (EPA) scientific knowledge and tools with National Estuary Program (NEP) planning and management expertise to address environmental challenges in important estuarine ecosystems. The non-regulatory National Estuary Program (NEP) was outlined in the Clean Water Act to provide stakeholders an opportunity to monitor and manage ‘nationally significant’ estuaries. Currently there are 28 estuaries in the NEP, broadly distributed across the Atlantic, Pacific and Gulf Coasts, and in Puerto Rico. The local NEP management conferences must address a variety of environmental issues, from water quality and natural resources to coastal and watershed development. While the underlying objectives of each NEP are quite similar, each has unique landscapes, land uses, waterbodies, habitats, biological resources, economies and social culture. Consequently, the effects and severity of anthr

  2. Sault Tribe Wind Energy Feasibility Study

    SciTech Connect

    Toni Osterhout; Global Energy Concepts

    2005-07-31

    The Sault Tribe conducted a feasibility study on tribal lands in the Upper Peninsula of Michigan to determine the technical and economic feasibility of both small and large-scale wind power development on tribal lands. The study included a wind resource assessment, transmission system analysis, engineering and regulatory analyzes and assessments.

  3. Alien reef-building polychaete drives long-term changes in invertebrate biomass and diversity in a small, urban estuary

    NASA Astrophysics Data System (ADS)

    McQuaid, K. A.; Griffiths, C. L.

    2014-02-01

    Two of the greatest threats to native biodiversity are the construction of artificial structures in natural environments and the introduction of invasive species. As the development and urbanisation of estuaries continues at an increasing rate worldwide, these environments are being simultaneously affected by these threats. This study quantifies the spread of an invasive reef-building polychaete, Ficopomatus enigmaticus, in a small, highly manipulated urban estuary in South Africa and investigates its role as an ecosystem engineer. Anthropogenic changes to the Zandvlei Estuary, including construction of a rubble weir and canalisation near the estuary mouth, construction of an extensive marina development and hardening of the banks with concrete, have facilitated the expansion of F. enigmaticus. The standing stock of F. enigmaticus increased from 13.69 t, as measured in 1986, to 50.03 t in 2012, due both to increase in the total area colonised and standing stock per m2. Since F. enigmaticus reefs support a greater biomass of infauna than adjacent sandy areas, total invertebrate biomass in the estuary is estimated to have increased from less than 0.30 t in 1942, to over 56.80 t in 2012, due mainly to hardening of banks in parts of the main estuary with concrete and construction of a marina system. A positive correlation between reef mass and infaunal biomass, density and diversity was also found.

  4. The Peel Inlet-Harvey Estuary Study.

    ERIC Educational Resources Information Center

    Walker, Warren; Black, Ronald

    1979-01-01

    Describes how the department of physics of the Western Australian Institute of Technology (WAIT) has been involved in the Peel Inlet-Harvey Estuary study. An appendix which presents the departmental approach to curriculum matters is also included. (HM)

  5. Microplastic in three urban estuaries, China.

    PubMed

    Zhao, Shiye; Zhu, Lixin; Li, Daoji

    2015-11-01

    Estuarine Microplastics (MPs) are limited to know globally. By filtering subsurface water through 330 μm nets, MPs in Jiaojiang, Oujiang Estuaries were quantified, as well as that in Minjiang Estuary responding to Typhoon Soulik. Polymer matrix was analyzed by Raman spectroscopy. MP (<5 mm) comprised more than 90% of total number plastics. The highest MPs density was found in Minjiang, following Jiaojiang and Oujiang. Fibers and granules were the primary shapes, with no pellets found. Colored MPs were the majority. The concentrations of suspended microplastics determine their bioavailability to low trophic organisms, and then possibly promoting the transfer of microplastic to higher trophic levels. Polypropylene and polyethylene were the prevalent types of MPs analyzed. Economic structures in urban estuaries influenced on MPs contamination levels. Typhoon didn't influence the suspended MP densities significantly. Our results provide basic information for better understanding suspended microplastics within urban estuaries and for managerial actions.

  6. EPA'S BENTHIC HABITAT DATA FOR YAQUINA ESTUARY

    EPA Science Inventory

    Scientists at EPA's National Health and Environmental Effects Research Laboratory, Western Ecology Division (WED) have been studying seafloor (benthic) habitats in Yaquina estuary for several years. Those studies were conducted as parts of several research projects, including: e...

  7. Estuaries.

    ERIC Educational Resources Information Center

    Awkerman, Gary L.

    This publication is designed for use in standard science curricula to develop oceanologic manifestations of certain science topics. Included are teacher guides, student activities, and demonstrations designed to impart ocean understanding to high school students. When the student has completed this unit, he should be able to: (1) define an…

  8. Rabbit tibial periosteum and saphenous arteriovenous vascular bundle as an in vivo bioreactor to construct vascularized tissue-engineered bone: a feasibility study.

    PubMed

    Han, Dong; Guan, Xiaoyi; Wang, Jian; Wei, Jiao; Li, Qingfeng

    2014-02-01

    The aim of this project was to construct vascularized tissue-engineered living bone with an autologous vascular network by means of a rabbit bioreactor in vivo. The key components of the in vivo bioreactor for bone formation were the vascularized tibial periosteum and the saphenous vascular bundle. Beta-tricalcium phosphate (β-TCP) scaffolds were implanted into the in vivo bioreactor (vascular pedicle implantation and vascularized periosteum encapsulation). At 4 weeks postsurgery, new bone formation was mainly "cartilage-bone inducing" in the inner periosteum, and was primarily seen in the outer aspects of the scaffold with some amount in the middle part as well. Microvascular infusion showed that direct revascularization of β-TCP was obtained by means of vascular implantation. Triple staining results showed a large amount of blue collagen fibers. Vascular endothelial growth factor immunohistochemical staining displayed endothelial cells of new blood vessels in bone tissue. The bioreactor established in this study can be used to prepare tissue-engineered bone with a vascular network.

  9. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2005

    SciTech Connect

    Diefenderfer, Heida L.; Thom, Ronald M.; Borde, Amy B.; Roegner, G. C.; Whiting, Allan H.; Johnson, Gary E.; Dawley, Earl; Skalski, John R.; Vavrinec, John; Ebberts, Blaine D.

    2006-12-20

    This report is the second annual report of a six-year project to evaluate the cumulative effects of habitat restoration projects in the Columbia River Estuary, conducted by Pacific Northwest National Laboratory's Marine Sciences Laboratory, NOAA's National Marine Fisheries Service Pt. Adams Biological Field Station, and the Columbia River Estuary Study Taskforce for the US Army Corps of Engineers. In 2005, baseline data were collected on two restoration sites and two associated reference sites in the Columbia River estuary. The sites represent two habitat types of the estuary--brackish marsh and freshwater swamp--that have sustained substantial losses in area and that may play important roles for salmonids. Baseline data collected included vegetation and elevation surveys, above and below-ground biomass, water depth and temperature, nutrient flux, fish species composition, and channel geometry. Following baseline data collection, three kinds of restoration actions for hydrological reconnection were implemented in several locations on the sites: tidegate replacements (2) at Vera Slough, near the city of Astoria in Oregon State, and culvert replacements (2) and dike breaches (3) at Kandoll Farm in the Grays River watershed in Washington State. Limited post-restoration data were collected: photo points, nutrient flux, water depth and temperature, and channel cross-sections. In subsequent work, this and additional post-restoration data will be used in conjunction with data from other sites to estimate net effects of hydrological reconnection restoration projects throughout the estuary. This project is establishing methods for evaluating the effectiveness of individual projects and a framework for assessing estuary-wide cumulative effects including a protocol manual for monitoring restoration and reference sites.

  10. Remedial investigation/feasibility study Work Plan and addenda for Operable Unit 4-12: Central Facilities Area Landfills II and III at the Idaho National Engineering Laboratory

    SciTech Connect

    Keck, K.N.; Stormberg, G.J.; Porro, I.; Sondrup, A.J.; McCormick, S.H.

    1993-07-01

    This document is divided into two main sections -- the Work Plan and the addenda. The Work Plan describes the regulatory history and physical setting of Operable Unit 4-12, previous sampling activities, and data. It also identifies a preliminary conceptual model, preliminary remedial action alternatives, and preliminary applicable or relevant and appropriate requirements. In addition, the Work Plan discusses data gaps and data quality objectives for proposed remedial investigation activities. Also included are tasks identified for the remedial investigation/feasibility study (RI/FS) and a schedule of RI/FS activities. The addenda include details of the proposed field activities (Field Sampling Plan), anticipated quality assurance activities (Quality Assurance Project Plan), policies and procedures to protect RI/FS workers and the environment during field investigations (Health and Safety Plan), and policies, procedures, and activities that the Department of Energy will use to involve the public in the decision-making process concerning CFA Landfills II and III RI/FS activities (Community Relations Plan).

  11. Simulating Suspended Silt Concentrations in the Ems Estuary, The Netherlands

    NASA Astrophysics Data System (ADS)

    Grasmeijer, B. T.

    2009-04-01

    applied a beta release of the state-of-the-art Delft3D numerical model for this purpose. The model includes a new sediment transport module published by Van Rijn (2007, 2007a). The vertical distribution of the suspended sediment concentration in the transport module depends on the effective settling velocity of the sediment, the bed shear velocity and the turbulence. The silt transport is simulated every time step together with the flow (online), which means that the impact of the calculated concentration is accounted for in the hydrodynamics. Major challenge was to accurately simulate the relatively high suspended silt concentrations observed near the estuarine turbidity maximum. 3 Results The paper will compare observed and predicted water levels, salinity distributions and suspended silt concentrations. Figure 1 shows an example of predicted depth-averaged suspended silt concentrations during spring high tide without waves. Under these conditions the depth-averaged concentrations decrease from about 2 kg/m3 in the Unterems (upstream of Emden) to almost zero seaward of Borkum. PIC Figure 1: Figure 2 Observed and predicted salinities in the upper part of the water column along the estuary The presence of waves will increase the concentrations on the shoals but have a limited effect on the concentrations in the channels. Figure 2 presents observed and predicted salinities along the estuary. The model results encouragingly agree with the observations. PIC 4 References De Jonge, V.N., 1992. Tidal flow and residual flow in the Ems estuary. Estuarine, Coastal and Shelf Science, 34: 1-22. Van Rijn, L.C., 2007. Unified View of Sediment Transport by Currents and Waves. I: Initiation of Motion, Bed Roughness, and Bed-Load Transport. Journal of Hydraulic Engineering, 133(6): 649-667. Van Rijn, L.C., 2007a. Unified View of Sediment Transport by Currents and Waves. II: Suspended Transport. Journal of Hydraulic Engineering, 133(6): 668-689.

  12. The Estuary Book: A Guide to Promoting Understanding and Regional Management of Maine's Estuaries and Embayments.

    ERIC Educational Resources Information Center

    Ruffing, Jenny

    The objective of this document is to provide information about estuaries, the impact of uses on the environmental health of an estuary, and what communities and concerned individuals can do to manage and protect their local estuarine resources successfully. Much of the information presented here pertains to other embayments along the Maine coast…

  13. A trophic model for the Danshuei River Estuary, a hypoxic estuary in northern Taiwan.

    PubMed

    Lin, Hsing-Juh; Shao, Kwang-Tsao; Jan, Rong-Quen; Hsieh, Hwey-Lian; Chen, Chang-Po; Hsieh, Li-Yung; Hsiao, Yi-Ting

    2007-11-01

    The estuary of the Danshuei River, a hypoxic subtropical estuary, receives a high rate of untreated sewage effluent. The Ecopath with Ecosim software system was used to construct a mass-balanced trophic model for the estuary, and network analysis was used to characterize the structure and matter flow in the food web. The estuary model was comprised of 16 compartments, and the trophic levels varied from 1.0 for primary producers and detritus to 3.0 for carnivorous and piscivorous fishes. The large organic nutrient loading from the upper reaches has resulted in detritivory being more important than herbivory in the food web. The food-chain length of the estuary was relatively short when compared with other tropical/subtropical coastal systems. The shortness of food-chain length in the estuary could be attributed to the low biomass of the top predators. Consequently, the trophic efficiencies declined sharply for higher trophic levels due to low fractions of flows to the top predators and then high fractions to detritus. The low biomass of the top predators in the estuary was likely subject to over-exploitation and/or hypoxic water. Summation of individual rate measurements for primary production and respiration yielded an estimate of -1791 g WW m(-2) year(-1), or -95 g C m(-2) year(-1), suggesting a heterotrophic ecosystem, which implies that more organic matter was consumed than was produced in the estuary.

  14. ESTIMATING THE CONDITION OF GULF OF MEXICO ESTUARIES: NATIONAL COASTAL ASSESSMENT AND NATIONAL ESTUARY PROGRAM

    EPA Science Inventory

    Estuaries in the Gulf of Mexico have been monitored since 1991 to determine the condition of water, sediment, and biota. More recently, through the National Coastal Assessment (NCA), U.S. EPA has provided a comprehensive estimate of the condition of U.S. estuaries, including a re...

  15. ENGINEERING FEASIBILITY AND ECONOMICS OF CO2 SEQUESTRATION/USE ON AN EXISTING COAL-FIRED POWER PLANT: A LITERATURE REVIEW

    SciTech Connect

    Carl R. Bozzuto; Nsakala ya Nsakala

    2000-01-31

    The overall objective of this study is to evaluate the technical feasibility and the economics of alternate CO{sub 2} capture and sequestration/use technologies for retrofitting an existing pulverized coal-fired power plant. To accomplish this objective three alternative CO{sub 2} capture and sequestration systems will be evaluated to identify their impact on an existing boiler, associated boiler auxiliary components, overall plant operation and performance and power plant cost, including the cost of electricity. The three retrofit technologies that will be evaluated are as follows: (1) Coal combustion in air, followed by CO{sub 2} separation from flue gas with Kerr-McGee/ABB Lummus Global's commercial MEA-based absorption/stripping process. (2) Coal combustion in an O{sub 2}/CO{sub 2} environment with CO{sub 2} recycle. (3) Coal combustion in air with oxygen removal and CO{sub 2} captured by tertiary amines In support of this objective and execution of the evaluation of the three retrofit technologies a literature survey was conducted. It is presented in an ''annotated'' form, consistent with the following five sections: (1) Coal Combustion in O{sub 2}/CO{sub 2} Media; (2) Oxygen Separation Technologies; (3) Post Combustion CO{sub 2} Separation Technologies; (4) Potential Utilization of CO{sub 2}; and (5) CO{sub 2} Sequestration. The objective of the literature search was to determine if the three retrofit technologies proposed for this project continue to be sound choices. Additionally, a review of the literature would afford the opportunity to determine if other researchers have made significant progress in developing similar process technologies and, in that context, to revisit the current state-of-the-art. Results from this literature survey are summarized in the report.

  16. Multi-Scale Action Effectiveness Research in the Lower Columbia River and Estuary, 2012

    SciTech Connect

    Johnson, Gary E.; Sather, Nichole K.; Storch, Adam; Johnson, Jeff; Skalski, J. R.; Teel, D. J.; Brewer, Taylor; Bryson, Amanda J.; Dawley, Earl M.; Kuligowski, D. R.; Whitesel, T.; Mallette, Christine

    2013-11-30

    The study reported herein was conducted for the U.S. Army Corps of Engineers, Portland District (USACE) by researchers at the Pacific Northwest National Laboratory (PNNL), Oregon Department of Fish and Wildlife (ODFW), National Marine Fisheries Service (NMFS), University of Washington (UW), and U.S. Fish and Wildlife Service (USFWS). The goal of the study was to evaluate the ecological benefits of restoration actions for juvenile salmon in the lower Columbia River and estuary (LCRE; rkm 0–234).

  17. Evaluation of Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2010

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Thom, Ronald M.; Roegner, G. Curtis; Ebberts, Blaine D.; Skalski, John R.; Borde, Amy B.; Dawley, Earl; Coleman, Andre M.; Woodruff, Dana L.; Breithaupt, Stephen A.; Cameron, April; Corbett, C.; Donley, Erin E.; Jay, D. A.; Ke, Yinghai; Leffler, K.; McNeil, C.; Studebaker, Cindy; Tagestad, Jerry D.

    2012-05-01

    This is the seventh and final annual report of a project (2004–2010) addressing evaluation of the cumulative effects of habitat restoration actions in the 235-km-long lower Columbia River and estuary. The project, called the Cumulative Effects (CE) study, was conducted for the U.S. Army Corps of Engineers Portland District by a collaboration of research agencies led by the Pacific Northwest National Laboratory. We achieved the primary goal of the CE study to develop a methodology to evaluate the cumulative effects of habitat actions in the Columbia Estuary Ecosystem Restoration Program. We delivered 1) standard monitoring protocols and methods to prioritize monitoring activities; 2) the theoretical and empirical basis for a CE methodology using levels-of-evidence; 3) evaluations of cumulative effects using ecological relationships, geo-referenced data, hydrodynamic modeling, and meta-analyses; and 4) an adaptive management process to coordinate and coalesce restoration efforts in the LCRE. A solid foundation has been laid for future comprehensive evaluations of progress made by the Columbia Estuary Ecosystem Restoration Program to understand, conserve, and restore ecosystems in the lower Columbia River and estuary.

  18. Environmental flow assessments for transformed estuaries

    NASA Astrophysics Data System (ADS)

    Sun, Tao; Zhang, Heyue; Yang, Zhifeng; Yang, Wei

    2015-01-01

    Here, we propose an approach to environmental flow assessment that considers spatial pattern variations in potential habitats affected by river discharges and tidal currents in estuaries. The approach comprises four steps: identifying and simulating the distributions of critical environmental factors for habitats of typical species in an estuary; mapping of suitable habitats based on spatial distributions of the Habitat Suitability Index (HSI) and adopting the habitat aggregation index to understand fragmentation of potential suitable habitats; defining variations in water requirements for a certain species using trade-off analysis for different protection objectives; and recommending environmental flows in the estuary considering the compatibility and conflict of freshwater requirements for different species. This approach was tested using a case study in the Yellow River Estuary. Recommended environmental flows were determined by incorporating the requirements of four types of species into the assessments. Greater variability in freshwater inflows could be incorporated into the recommended environmental flows considering the adaptation of potential suitable habitats with variations in the flow regime. Environmental flow allocations should be conducted in conjunction with land use conflict management in estuaries. Based on the results presented here, the proposed approach offers flexible assessment of environmental flow for aquatic ecosystems that may be subject to future change.

  19. Estuaries and coastal waters need help

    SciTech Connect

    Levenson, H.

    1987-11-01

    For years, our marine environments-estuaries, coastal waters, and the open ocean-have been used extensively by coastal communities and industries for the disposal of various wastes. Historically, marine waste disposal has been relatively cheap and has solved some short-term waste-management problems; however, its consequences include a general trend toward environmental degradation, particularly in estuaries and coastal waters. Thus, without protective measures, the next few decades will witness degradation in many estuaries and some coastal waters around the country. The extent of current degradation varies greatly around the country. Although it is difficult to ascertain cause and effect relationships, enough evidence exists to conclude that the pollutants in question include disease-causing microorganisms, oxygen-demanding substances, particulate material, metals, and organic chemicals. Two statutes form the basis of most federal regulatory efforts to combat marine pollution: the Marine Protection, Research, and Sanctuaries Act (MPRSA) and the Clean Water Act (CWA). The MPRSA regulates the dumping of wastes in coastal and open-ocean waters, whereas the CWA has jurisdiction over pipeline discharges in all marine waters, wastes dumped in estuaries, and runoff. Many people consider that the passage and implementation of these two acts and their ensuing amendments established a statutory structure sufficient to protect the nation's waters from pollution. However, these provisions have not protected some estuaries and coastal waters from degradation.

  20. Tampa Bay Estuary Program and Restore Americas Estuaries to Receive Third Place Gulf Guardian Award in the Partnerships Category

    EPA Pesticide Factsheets

    ATLANTA - Today the Gulf of Mexico Program announced that Tampa Bay Estuary Program & Restore America's Estuaries will receive a Third Place 2015 Gulf Guardian Award in the Partnerships Category. The award will be given tonight at an awards ceremony at

  1. Facilitation of the Estuary/Ocean Subgroup and the Expert Regional Technical Group, Fiscal Year 2014 Annual Report

    SciTech Connect

    Johnson, Gary E.

    2014-09-01

    This document is the annual report for fiscal year 2014 for the project called Facilitation of the Estuary/Ocean Subgroup (EOS) and the Expert Regional Technical Group (ERTG). Pacific Northwest National Laboratory (PNNL) conducted the project for the Bonneville Power Administration. The EOS and ERTG are part of the research, monitoring, and evaluation and habitat restoration efforts, respectively, developed by the Action Agencies (BPA, U.S. Army Corps of Engineers) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System and implemented under the Columbia Estuary Ecosystem Restoration Program.

  2. The Estuary Guide. Level 3: High School. Draft.

    ERIC Educational Resources Information Center

    Alexander, Glen; And Others

    Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the high school level seeks to teach what estuaries are; provide opportunities to practice decision-making that affects estuaries; and encourage students to…

  3. Dissolved Trace Metals in the Tay Estuary

    NASA Astrophysics Data System (ADS)

    Owens, R. E.; Balls, P. W.

    1997-04-01

    Dissolved trace metals have been studied over an annual cycle in the relatively pristine Tay estuary (Scotland). The absence of a major anthropogenic signal has enabled some of the more subtle natural processes controlling trace metal distributions to be identified. Concentration ranges of dissolved metals in the Tay are similar to, or lower than, those observed in more industrialized estuaries. All metals behave non-conservatively in the Tay. Interactions with biogenic and detrital particulate phases are important in controlling dissolved trace metal concentrations. The degradation of organic matter appears to be particularly important for Cu. Removal of dissolved metals was observed in the turbidity maximum zone; a simple model was used to demonstrate that this could be accounted for by adsorption onto suspended particulate matter. At high salinity, coincident peaks of all six metals with ammonia and phosphate are attributed to sewage inputs from Dundee at the mouth of the estuary.

  4. Facilitation of the Estuary/Ocean Subgroup and the Expert Regional Technical Group, Fiscal Year 2013 Annual Report

    SciTech Connect

    Johnson, Gary E.; Sather, Nichole K.

    2013-10-30

    This project covers facilitation of the Estuary/Ocean Subgroup (EOS) for federal research, monitoring, and evaluation (RME) and the Expert Regional Technical Group (ERTG) for estuary habitat restoration. The EOS is part of the research, monitoring, and evaluation effort that the Action Agencies (Bonneville Power Administration [BPA], U.S. Army Corps of Engineers [Corps], U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to operation of the Federal Columbia River Power System (FCRPS). The EOS is tasked by National Marine Fisheries Service (NMFS) and the Action Agencies (AAs) to design and coordinate implementation of the federal RME plan for the lower Columbia River and estuary, including the river’s plume in the ocean. Initiated in 2002, the EOS is composed of members from BPA, the Corps, NMFS, and Pacific Northwest National Laboratory’s (PNNL’s) Marine Sciences Laboratory, and other agencies as necessary.

  5. Establishing nursery estuary otolith geochemical tags for Sea Bass (Dicentrarchus labrax): Is temporal stability estuary dependent?

    NASA Astrophysics Data System (ADS)

    Ryan, Diarmuid; Wögerbauer, Ciara; Roche, William

    2016-12-01

    The ability to determine connectivity between juveniles in nursery estuaries and adult populations is an important tool for fisheries management. Otoliths of juvenile fish contain geochemical tags, which reflect the variation in estuarine elemental chemistry, and allow discrimination of their natal and/or nursery estuaries. These tags can be used to investigate connectivity patterns between juveniles and adults. However, inter-annual variability of geochemical tags may limit the accuracy of nursery origin determinations. Otolith elemental composition was used to assign a single cohort of 0-group sea bass Dicentrarchus labrax to their nursery estuary thus establishing an initial baseline for stocks in waters around Ireland. Using a standard LDFA model, high classification accuracies to nursery sites (80-88%) were obtained. Temporal stability of otolith geochemical tags was also investigated to assess if annual sampling is required for connectivity studies. Geochemical tag stability was found to be strongly estuary dependent.

  6. National estuary program guidance: Technical characterization in the National Estuary Program

    SciTech Connect

    Not Available

    1994-06-01

    Estuaries are waterways, such as bays and sounds, where fresh water drained from the surrounding watershed mixes with salt water from the ocean. Section 320 of the Clean Water Act established the National Estuary Program (NEP) to identify nationally significant estuaries threatened by pollution, development, or overuse and to promote the preparation of comprehensive management plans to ensure their ecological integrity. The program's goals are protection and improvement of water quality and enhancement of living resources. To reach these goals, the Administrator of the U.S. Environmental Protection Agency (EPA) convenes management conferences for each estuary in the NEP to provide a forum for consensus building and problem solving among interested agencies and user groups.

  7. PECONIC ESTUARY: AN ASSESSMENT OF SHELLFISH RESOURCES IN THE TRIBUTARIES AND EMBAYMENTS OF THE PECONIC ESTUARY

    EPA Science Inventory

    Executive Summary Historically, the Peconic Estuary's shellfish resources have supported significant fisheries for a number of species including hard clams, oysters and bay scallops. However, distribution and abundance data for the tributaries and embayments within the Peconic Es...

  8. Historic Habitat Opportunities and Food-Web Linkages of Juvenile Salmon in the Columbia River Estuary, Annual Report of Research.

    SciTech Connect

    Bottom, Daniel L.; Simenstad, Charles A.; Campbell, Lance

    2009-05-15

    In 2002 with support from the U.S. Army Corps of Engineers (USACE), an interagency research team began investigating salmon life histories and habitat use in the lower Columbia River estuary to fill significant data gaps about the estuary's potential role in salmon decline and recovery . The Bonneville Power Administration (BPA) provided additional funding in 2004 to reconstruct historical changes in estuarine habitat opportunities and food web linkages of Columbia River salmon (Onchorhynchus spp.). Together these studies constitute the estuary's first comprehensive investigation of shallow-water habitats, including selected emergent, forested, and scrub-shrub wetlands. Among other findings, this research documented the importance of wetlands as nursery areas for juvenile salmon; quantified historical changes in the amounts and distributions of diverse habitat types in the lower estuary; documented estuarine residence times, ranging from weeks to months for many juvenile Chinook salmon (O. tshawytscha); and provided new evidence that contemporary salmonid food webs are supported disproportionately by wetland-derived prey resources. The results of these lower-estuary investigations also raised many new questions about habitat functions, historical habitat distributions, and salmon life histories in other areas of the Columbia River estuary that have not been adequately investigated. For example, quantitative estimates of historical habitat changes are available only for the lower 75 km of the estuary, although tidal influence extends 217 km upriver to Bonneville Dam. Because the otolith techniques used to reconstruct salmon life histories rely on detection of a chemical signature (strontium) for salt water, the estuarine residency information we have collected to date applies only to the lower 30 or 35 km of the estuary, where fish first encounter ocean water. We lack information about salmon habitat use, life histories, and growth within the long tidal

  9. Climate change and its impacts on estuaries

    EPA Science Inventory

    Past, present, and future research by WED scientists in the TEP region will be described to lay the foundation for examination of potential climate change effects on estuaries and the broader coastal zone in the Pacific Northwest (PNW). Results from National Coastal Assessments,...

  10. Kaua'i: Streams and Estuaries.

    ERIC Educational Resources Information Center

    Hawkins, John, Ed.; Murakami, Colleen, Ed.

    Designed to help teachers develop students' awareness and understanding of some of Hawaii's endangered aquatic resources, this module contains activities and instructional suggestions for use with intermediate as well as high school students. The module is divided into two sections which explore the streams and estuaries of Kauai. Activities in…

  11. Estuaries and Tidal Marshes. Habitat Pac.

    ERIC Educational Resources Information Center

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    This educational packet consists of an overview, three lesson plans, student data sheets, and a poster. The overview examines estuaries and tidal or salt marshes by discussing the plants and animals in these habitats, marsh productivity, benefits and management of the habitats, historical aspects, and development and pollution. A glossary and list…

  12. BCG Approaches for Improved Management of Estuaries

    EPA Science Inventory

    Estuaries and other complex aquatic systems are exposed to a variety of stressors that act at several scales, but are managed piecemeal - - often resulting in a “death by 1000 cuts” caused by cumulative impacts to these valued resources. To address this, managers need tools that...

  13. INDICATORS OF ECOSYSTEM INTEGRITY FOR ESTUARIES

    EPA Science Inventory

    Jordan, Stephen J. and Lisa M. Smith. In press. Indicators of Ecosystem Integrity for Estuaries. In: Proceedings of the Estuarine Indicators Workshop, 29-31 October 2003, Sanibel Island, FL. Sanibel-Captiva Conservation Foundation, Sanibel, FL. 23 p. (ERL,GB 1194).

    Ideal ...

  14. Restoration of the Golden Horn Estuary (Halic).

    PubMed

    Coleman, Heather M; Kanat, Gurdal; Aydinol Turkdogan, F Ilter

    2009-12-01

    Restoration of the iconic Golden Horn Estuary in Istanbul, Turkey was a substantial political, logistical, ecological, and social challenge. Forty years of uncontrolled industrial and urban growth resulted in thick layers of anoxic sediment, toxic bacteria, strong hydrogen sulfide odor, and ecologically unlivable conditions. The major components of restoration, spanning two decades, have included (1) demolition and relocation of industries and homes along the shore, (2) creation of wastewater infrastructure, (3) removal of anoxic sludge from the estuary, (4) removal of a floating bridge that impeded circulation, and (5) creation of cultural and social facilities. Although Turkey is not known as an environmental leader in pollution control, the sum of these efforts was largely successful in revitalizing the area through dramatic water quality improvement. Consequently, the estuary is once again inhabitable for aquatic life as well as amenable to local resource users and foreign visitors, and Istanbul has regained a lost sense of cultural identity. This paper focuses on literature review and personal interviews to discuss the causes of degradation, solutions employed to rehabilitate the estuary, and subsequent physicochemical, ecological, and social changes.

  15. Padilla Bay: The Estuary Guide. Level 2.

    ERIC Educational Resources Information Center

    Friesem, Judy; Lynn, Valerie, Ed.

    Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the middle school level is designed for use with the on-site program developed by the Padilla Bay National Esturine Research Reserve (Washington). The guide…

  16. Listening to Estuary English in Singapore

    ERIC Educational Resources Information Center

    Deterding, David

    2005-01-01

    In Singapore, many people are not familiar with Estuary English (EE), the variety of English becoming popular in much of southern England. In the current study, when students listened to interviews with EE speakers and were asked to transcribe orthographically what they heard, most of them had severe problems. Features of pronunciation that…

  17. Spectral Analysis of Columbia River Estuary Currents.

    DTIC Science & Technology

    1985-09-01

    D-A1i6i 689 SPECTRAL ANALYSIS OF COLUMBIA RIVER ESTUARY CURRENTS 1/2 (U) ARMY E GINEER VATERWAYS EXPERIMENT STATION VICKCSBURG MS HYDRAULICS LAB B...26 PART IV: ANALYSIS PROCEDURES. .................... 29 *PART V: RESULTS AND DISCUSSION .. ................. 32 Astoria Winds...45 eStation T11B..........................46 Station T12. .......................... 46 Summary of Results

  18. Engine Fluid Leakage Detection: A Feasibility Study

    DTIC Science & Technology

    2011-07-01

    de détecter tout problème possible lié à la sécurité ou aux performances des moteurs à turbine à gaz d’aéronefs. Le signalement immédiat d’une fuite...l’utilisation d’un concept innovateur de capteurs ultrasoniques. On a évalué s’il était possible d’utiliser des transducteurs ultrasoniques, des...fonctionnement du moteur. Perspectives : Les prochaines étapes de conception d’un dispositif autonome consistent à créer un capteur ayant des capacités

  19. Charge Density Engineering: A Feasibility Study

    DTIC Science & Technology

    2013-11-22

    Fig 1: The two bonding topologies of the B2 compounds investigated. The A-B and B-B bonding topology is shown left, with turquoise spheres...right) in a B2 material. Bond points are shown as turquoise , rings as red, and cages as yellow spheres, while bond paths are shown as gray cylinders in

  20. Baseline ecological risk assessment of the Calcasieu Estuary, Louisiana: 1. Overview and problem formulation

    USGS Publications Warehouse

    MacDonald, Donald D.; Moore, Dwayne R.J.; Ingersoll, Christopher G.; Smorong, Dawn E.; Carr, R. Scott; Gouguet, Ron; Charters, David; Wilson, Duane; Harris, Tom; Rauscher, Jon; Roddy, Susan; Meyer, John

    2011-01-01

    A remedial investigation/feasibility study (RI/FS) of the Calcasieu Estuary cooperative site was initiated in 1998. This site, which is located in the southwestern portion of Louisiana in the vicinity of Lake Charles, includes the portion of the estuary from the saltwater barrier on the Calcasieu River to Moss Lake. As part of the RI/FS, a baseline ecological risk assessment (BERA) was conducted to assess the risks to aquatic organisms and aquatic-dependent wildlife exposed to environmental contaminants. The purpose of the BERA was to determine if adverse effects on ecological receptors are occurring in the estuary; to evaluate the nature, severity, and areal extent of any such effects; and to identify the substances that are causing or substantially contributing to effects on ecological receptors. This article describes the environmental setting and site history, identifies the chemicals of potential concern, presents the exposure scenarios and conceptual model for the site, and summarizes the assessment and measurement endpoints that were used in the investigation. Two additional articles in this series describe the results of an evaluation of effects-based sediment-quality guidelines as well as an assessment of risks to benthic invertebrates associated with exposure to contaminated sediment.

  1. Improving lakebed sediment quality in an urban estuary, Presque Isle Bay, Lake Erie, USA

    NASA Astrophysics Data System (ADS)

    Foyle, A. M.; Norton, K. P.

    2007-12-01

    Presque Isle Bay, Lake Erie, is a microtidal freshwater estuary on the North American Great Lakes. It is one of 40 remaining environmental Areas of Concern (AoCs) on the Great Lakes that have one or more water, habitat, or sediment quality impairments as defined by the International Joint Commission. In-situ natural capping using sediment from to-be-remediated watersheds and other sources is being considered as the most feasible means of remediating contaminated sediments in the estuary. A multi-decade sediment budget shows that, when localized anthropogenic effects are accounted for, the estuary net-accumulated sediment over time from three major sources: the Lake Erie littoral system (20%), streams (25%), and bank erosion and bluff recession (41%). The non-stream sources supply environmentally clean sediment from ancient coastal deposits along the shoreline, and from the modern littoral system. However, organic and metallic contaminants are supplied by streams and run-off and remain a remediation challenge. From a geological perspective, natural capping of contaminated sediment over the next several decades is a viable solution for the majority of the bay. The mechanism may not work effectively in all areas because approximately 25% of the bay floor is moderately net- erosional or accumulates sediments very slowly.

  2. A Hydrologic and Geomorphic Model of Estuary Breaching and Closure

    NASA Astrophysics Data System (ADS)

    Rich, A.; Keller, E. A.

    2012-12-01

    Many coastal estuaries are separated seasonally from the ocean by a swash-deposited beach berm. The opening of the inlet may occur by fluvial erosion of the beach berm and closure occurs when sand deposition outpaces erosion of the inlet. To better understand how the hydrology of estuaries affects breaching and closing patterns, a model is developed that incorporates an estuary hydrologic budget with a geormorphic model of the inlet system. When calibrated, the model is able to reproduce the initial seasonal breaching, seasonal closure, intermittent closures and breaches, and the low-streamflow estuary hydrology of the Carmel Lagoon, located in Central California. For two years when the estuary inlet drains directly across the beach-berm in accordance with model assumptions, the calibrated model predicts the observed 48-hour estuary stage amplitude with correlation coefficients of 0.77 and 0.65. For the calibrated model, streamflow is the predominant control on whether the estuary inlet is open or closed. In a series of sensitivity analyses, it is seen that the function of bar-built, coastal estuaries are sensitive to morphologic and hydrologic variations of the beach berm, and changes to the estuary storage itself. By varying individual components of the berm-system and estuary storage, the amount of the time the estuary is open changes -43 - 28% for the 18.2 model period. The morphology of the berm affects barrier groundwater flow, inlet hydraulics, and estuary storage. Importantly, the elevation of the berm determines the volume of water that must enter the estuary in order to breach, and it modulates the wave-overtopping flux. A high berm renders streamflow the predominant control on function and decreases the amount of time that the estuary is open by 4%, whereas a lower berm allows wave-overtopping to contribute to function and increases time open by 24%. By excavating an estuary, it will breach less frequently (-32% change in open) and store water up to 3

  3. Geothermal feasibility study for Malting Investments Inc

    SciTech Connect

    Not Available

    1981-10-01

    The engineering feasibility of using geothermal heat in the kilning, germination, and steep water cooling processes for a malting facility is determined. The study is based upon a malting facility with an annual capacity of malting three million bushels of clean graded barley per year or 8220 bushels per day. Capital cost figures used in the feasibility study are budget prices for the basic equipment only, they do not include any other costs such as installation, instrumentation or design and engineering costs. Utility prices are based upon $0.03 per kilowatt hour and $0.4548 per therm for natural gas.

  4. Ecological feasibility studies in restoration decision making.

    PubMed

    Hopfensperger, Kristine N; Engelhardt, Katharina A M; Seagle, Steven W

    2007-06-01

    The restoration of degraded systems is essential for maintaining the provision of valuable ecosystem services, including the maintenance of aesthetic values. However, restoration projects often fail to reach desired goals for a variety of ecologic, financial, and social reasons. Feasibility studies that evaluate whether a restoration effort should even be attempted can enhance restoration success by highlighting potential pitfalls and gaps in knowledge before the design phase of a restoration. Feasibility studies also can bring stakeholders together before a restoration project is designed to discuss potential disagreements. For these reasons, a feasibility study was conducted to evaluate the efficacy of restoring a tidal freshwater marsh in the Potomac River near Alexandria, Virginia. The study focused on science rather than engineering questions, and thus differed in approach from other feasibility studies that are mostly engineering driven. The authors report the framework they used to conduct a feasibility study to inform other potential restoration projects with similar goals. The seven steps of the framework encompass (1) initiation of a feasibility study, (2) compilation of existing data, (3) collection of current site information, (4) examination of case studies, (5) synthesis of information in a handbook, (6) meeting with selected stakeholders, and (7) evaluation of meeting outcomes. By conducting a feasibility study using the seven-step framework, the authors set the stage for conducting future compliance studies and enhancing the chance of a successful restoration.

  5. Fish composition and assemblage structure in three Eastern English Channel macrotidal estuaries: A comparison with other French estuaries

    NASA Astrophysics Data System (ADS)

    Selleslagh, Jonathan; Amara, Rachid; Laffargue, Pascal; Lesourd, Sandric; Lepage, Mario; Girardin, Michel

    2009-01-01

    This study has analysed for the first time fish composition and assemblage structures of three small macrotidal estuaries of the Eastern English Channel (EEC) and has explored the influences of 19 biotic and abiotic variables on the fish assemblages. Fish from Canche, Authie and Somme estuaries were collected during spring (June 2006 and May 2007) and autumn (September 2006) along the estuarine gradients using a 1.5 m beam trawl. Using identical sampling protocols, the study also analysed and compared for the first time taxonomic and functional aspects of the fish assemblages in 15 estuaries located along the Atlantic and English Channel coasts. SIMPER analysis showed high similarities in fish assemblages in the three EEC estuaries and during either spring or autumn periods. However, intra-estuary similarities were relatively low, indicating that fish assemblage structures (species richnesses or abundances) were more variable within the estuary (salinity gradient) than between estuaries and/or seasons (spring vs autumn). Although numerous environmental variables were included in the study, only 47% of the variability observed in the fish distribution was explained. Fish spatial variations in the EEC estuaries are mostly driven by abiotic variables as opposed to biological interactions. As indicated by CCA, salinity and muddy sediments were the two most important factors structuring the fish assemblages. The macrobenthos being very abundant in the EEC estuaries (580-1121 ind. m -2), the availability of potential prey is probably not a limiting factor in the utilization of estuaries by fish. Contrary to the majority of French estuaries dominated by estuarine species (ES), the fish assemblages of the EEC estuaries are clearly dominated by marine migrant (MM) species (65% on average) with high abundance of juveniles (mostly young-of-the-year). Cluster and SIMPROF's analyses distinguished the functional structure of the 15 estuarine fish assemblages into different

  6. Geophysical Assessment of the Control of a Jetty on a Barrier Beach and Estuary System

    NASA Astrophysics Data System (ADS)

    Ulrich, C.; Hubbard, S. S.; Peterson, J.; Blom, K.; Black, W.; Delaney, C.; Mendoza, J.

    2014-12-01

    An evaluation is underway at the Goat Rock State Park, located at the mouth of the Russian River near Jenner, CA, to quantify the influence of a man made jetty on the functioning of a barrier beach and associated implications for estuary fish habitat and flood control. Flow through the beach results from water level differences between the estuary and the ocean. When the estuary is closed or perched, one of the major sources of outflow from the lagoon is seepage flow through the barrier beach. The location and design of the jetty could be altering subsurface flow paths through the jetty and possibly impeding subsurface flow where the jetty is still intact. This will result in unnatural connectivity between the ocean and the estuary leading to atypical surface water elevations and possibly salinity imbalance. We are monitoring seepage through the jetty and beach berm with multiple surface and borehole geophysical methods, including: electrical resistivity (ERT), seismic refraction (SR), ground penetrating radar (GPR), and electromagnetic methods (EM). We use SR data to characterize deeper bedrock controls on beach barrier functioning; ERT and EM methods to characterize the beach sediment layers that could contribute to preferential flow paths during tide cycles in addition to preferential flow paths created by the jetty structure; time-lapse ERT and EM data to monitor moisture changes and mixing of saline and fresh water within the beach berm, and borehole ERT and GPR data to delineate the geometry of the (often buried) jetty. Preliminary ERT and EM results indicate two preferential flow paths through zones of missing jetty structure, while time-lapse borehole ERT data is expected to image saltwater flow impedance in zones of intact jetty structure. All data are being integrated with topography, tidal, borehole, and hydrological information and the results of the assessment will enable the Sonoma County Water Agency to develop the feasibility of alternatives to the

  7. 78 FR 9887 - Proposed Information Collection; Comment Request; National Estuaries Restoration Inventory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-12

    ... Estuaries Restoration Inventory AGENCY: National Oceanic and Atmospheric Administration (NOAA), Commerce... extension of a currently approved information collection. Collection of estuary habitat restoration project... to populate a restoration project database mandated by the Estuary Restoration Act of 2000....

  8. 78 FR 46332 - Proposed Information Collection Request; Comment Request; National Estuary Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-31

    ... AGENCY Proposed Information Collection Request; Comment Request; National Estuary Program AGENCY... to submit an information collection request (ICR), ``National Estuary Program'' (EPA ICR No. 1500.08... opportunity to submit additional comments to OMB. Abstract: The National Estuary Program (NEP)...

  9. Second International Symposium on the Biogeochemistry of Model Estuaries: Estuarine processes in global change. Final report

    SciTech Connect

    Windom, H.L.

    1991-12-31

    This report summarizes estuary events discussed at the symposium on biogeochemistry. Topics include; sedimentation, salinity, inputs and outputs of the estuary, effects of global change, and the need for effective sampling and modeling of estuaries.

  10. DPC loading feasibility study report

    SciTech Connect

    Dafoe, R.E.; Lopez, D.A.; Williams, K.L.

    1997-11-01

    Disposal of radioactive wastes now stored at the Idaho Chemical Processing Plant at the Idaho National Engineering and Environmental Laboratory is mandated under a ``Settlement Agreement`` between the Department of Energy and the State of Idaho. This study investigates the feasibility of using the Dry Transfer Cell facility to package waste into Dual Purpose Canisters for interim storage at the adjacent Dry Storage System comprised of an interim storage pad with NUHOMS{reg_sign} storage modules. The wastes would then be road-ready for eventual disposal in a permanent repository. The operating period for these activities is expected to be from 2015 to 2035.

  11. Interpreting the colour of an estuary

    NASA Astrophysics Data System (ADS)

    Bowers, D. G.; Evans, D.; Thomas, D. N.; Ellis, K.; Williams, P. J. le B.

    2004-01-01

    This paper explores the possibility of using water colour to quantify the concentration of coloured dissolved organic matter (CDOM), and through it, dissolved organic carbon (DOC) and salinity in a turbid estuary in which suspended sediments also influence water colour. The motivation of the work is that the method could be applied to water colour measurements made remotely from an aircraft (or, in larger estuaries, a satellite) enabling near-synoptic mapping of surface salinity and DOC distributions. The paper describes observations at 29 stations distributed along the salinity gradient of the Conwy estuary in North Wales. At each station, surface water samples were collected and analysed for salinity, concentrations of DOC, chlorophyll and suspended particles and absorption spectra of CDOM, or yellow substance. Profiles were made of both upwelling and downwelling irradiance in four narrow band channels, and these were used to calculate irradiance reflection and attenuation coefficients. Results show that spectrally averaged light absorption in the estuary is caused principally and equally by mineral suspended solids and yellow substance, with water and chlorophyll in third and fourth place. The CDOM is strongly correlated ( R2=0.99) in a negative sense with salinity, and more weakly correlated with DOC. There is a linear relationship between CDOM and the ratio of reflection coefficients in the red (670 nm) and blue-green (490 nm) parts of the spectrum, which could be applied to remote sensing; the slope and intercept of the relationship are however different to those found in less turbid water bodies. It is shown that the change in slope and intercept are consistent with the presence, in the Conwy estuary, of suspended particles which influence the water colour. A method is described and tested for inverting water colour measurements in a turbid estuary to give estimates of CDOM in the presence of suspended particles. The solution, which has not been adjusted to

  12. Mesozooplankton affinities in a recovering freshwater estuary

    NASA Astrophysics Data System (ADS)

    Chambord, Sophie; Maris, Tom; Colas, Fanny; Van Engeland, Tom; Sossou, Akoko-C.; Azémar, Frédéric; Le Coz, Maïwen; Cox, Tom; Buisson, Laetitia; Souissi, Sami; Meire, Patrick; Tackx, Michèle

    2016-08-01

    Water quality of the Scheldt estuary (Belgium/The Netherlands) has considerably improved in recent years, especially in the upstream, freshwater reaches. Within the zooplankton community, the copepod Eurytemora affinis, typically abundant in brackish water and quasi-absent from freshwater before 2007, has since substantially developed in the latter, where it now represents 90% of the crustacean mesozooplankton community. Simultaneously, cyclopoid copepod abundance has greatly decreased, while cladoceran abundance did not change. The study aim was: 1) to verify if the zooplankton community described for the period 2007-2009 by Mialet et al. (2011) has stabilized until present, and 2) to look for the environmental conditions favouring E. affinis development and causing changes in the upstream freshwater zooplankton community. The 2002-2012 temporal evolution of the zooplankton distribution at three stations in the upstream freshwater Scheldt estuary was analyzed. Water quality remained better after 2007 than before, and some factors revealed continuous improvement in annual mean concentrations (e.g. increase in O2, decrease in BOD5 and NH4sbnd N concentration). The increase in oxygen and the decrease in NH4sbnd N concentration, together with low discharge during summer were the main environmental factors explaining the development and timing of E. affinis in the upstream freshwater reach. In this reach, E. affinis maximal abundance is shifted to higher temperatures (summer) compared to its typical maximum spring abundance peak in the brackish zone of the Scheldt estuary and in most temperate estuaries. The changes in zooplankton community followed a temporal and spatial gradient induced by the spatio-temporal evolution of water quality improvement. The most downstream station (3) allowed E. affinis development (oxygen concentration > 4 mg L-1; NH4sbnd N concentration < 2 mg L-1, discharge (Q) < 50 m3 s-1) from 2007 onwards, and this station showed the highest E

  13. Small estuary, big port - progress in the management of the Stour-Orwell Estuary system

    NASA Astrophysics Data System (ADS)

    Spearman, Jeremy; Baugh, John; Feates, Nigel; Dearnaley, Mike; Eccles, Dan

    2014-10-01

    Management of port development is increasingly challenging because of the competitive requirement for deeper channels and because of the need to preserve important coastal wetlands which function as both habitat and flood defence. This paper describes the management of the Stour/Orwell Estuary system, Eastern England, an estuary system which has experienced considerable development and morphological change. The estuary is internationally important for its wetland bird populations and the intertidal areas of the estuary system are protected under European legislation. It is also the location of the Port of Felixstowe. In 1998/2000 the approach channel to the Port of Felixstowe was deepened from -12.5 mCD to -14.5 mCD. This paper describes the effects of the approach channel deepening, the approach taken to identifying the potential impact to intertidal habitat resulting from the deepening, the sediment recycling implemented as mitigation to prevent increased loss of habitat and the subsequent response of the estuary system to this intervention.

  14. Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, Annual Report 2010

    SciTech Connect

    Diefenderfer, Heida L.; Johnson, Gary E.; Sather, Nichole K.; Skalski, J. R.; Dawley, Earl M.; Coleman, Andre M.; Ostrand, Kenneth G.; Hanson, Kyle C.; Woodruff, Dana L.; Donley, Erin E.; Ke, Yinghai; Buenau, Kate E.; Bryson, Amanda J.; Townsend, Richard L.

    2011-10-01

    This report describes the 2010 research conducted under the U.S. Army Corps of Engineers (USACE) project EST-P-09-1, titled Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, and known as the 'Salmon Benefits' study. The primary goal of the study is to establish scientific methods to quantify habitat restoration benefits to listed salmon and trout in the lower Columbia River and estuary (LCRE) in three required areas: habitat connectivity, early life history diversity, and survival (Figure ES.1). The general study approach was to first evaluate the state of the science regarding the ability to quantify benefits to listed salmon and trout from habitat restoration actions in the LCRE in the 2009 project year, and then, if feasible, in subsequent project years to develop quantitative indices of habitat connectivity, early life history diversity, and survival. Based on the 2009 literature review, the following definitions are used in this study. Habitat connectivity is defined as a landscape descriptor concerning the ability of organisms to move among habitat patches, including the spatial arrangement of habitats (structural connectivity) and how the perception and behavior of salmon affect the potential for movement among habitats (functional connectivity). Life history is defined as the combination of traits exhibited by an organism throughout its life cycle, and for the purposes of this investigation, a life history strategy refers to the body size and temporal patterns of estuarine usage exhibited by migrating juvenile salmon. Survival is defined as the probability of fish remaining alive over a defined amount of space and/or time. The objectives of the 4-year study are as follows: (1) develop and test a quantitative index of juvenile salmon habitat connectivity in the LCRE incorporating structural, functional, and hydrologic components; (2) develop

  15. HYDRODYNAMIC SIMULATION OF THE UPPER POTOMAC ESTUARY.

    USGS Publications Warehouse

    Schaffranck, Raymond W.

    1986-01-01

    Hydrodynamics of the upper extent of the Potomac Estuary between Indian Head and Morgantown, Md. , are simulated using a two-dimensional model. The model computes water-surface elevations and depth-averaged velocities by numerically integrating finite-difference forms of the equations of mass and momentum conservation using the alternating direction implicit method. The fundamental, non-linear, unsteady-flow equations, upon which the model is formulated, include additional terms to account for Coriolis acceleration and meteorological influences. Preliminary model/prototype data comparisons show agreement to within 9% for tidal flow volumes and phase differences within the measured-data-recording interval. Use of the model to investigate the hydrodynamics and certain aspects of transport within this Potomac Estuary reach is demonstrated. Refs.

  16. Modelling the Physical System of Belawan Estuary

    NASA Astrophysics Data System (ADS)

    Tarigan, A. P. M.; Swandana, D.; Isma, F.

    2017-03-01

    Belawan estuary represents one of the most complex and fascinating mixed environments of sea and land, where not only habitat of rich biodiversity but also international seaport infrastructure are at stake. It is therefore a matter of considerable importance to understand the physical system which characterizes the dynamics of the estuarine water. The purpose of this study is to model the changing water depths, tidal currents, salt, temperature and sediment concentration over a long stretch of Belawan estuary on an hourly basis. The first essential step is to define the bathymetry based on which other physical parameters are simulated. The study is accomplished by building working computer modules which simplify and model the systems complexities. It should be noted that model validation and improvement is the subject of the next study.

  17. Differences in the structure of copepod assemblages in four tropical estuaries: Importance of pollution and the estuary hydrodynamics.

    PubMed

    Araujo, Adriana V; Dias, Cristina O; Bonecker, Sérgio L C

    2017-02-15

    We examined the relationship between pollution and structure of copepod assemblages in estuaries, using sampling standardization of salinity range to reduce the effects of "Estuarine Quality Paradox". Copepod assemblages were analyzed in four Southeast Brazilian estuaries with different water quality levels and different hydrodynamic characteristics. The pollution negatively impacted the descriptors of the assemblage structure. The distribution of structure of copepod assemblages also showed a main separation trend between the most polluted estuaries and those less polluted. Temperature was the main factor affecting the assemblage structuring in the four estuaries. This factor acted in synergism with the effects of pollution impact and physical characteristics of the estuaries on the structure of copepod assemblages, supporting the potential vulnerability of coastal environments due to nutrient enrichment associated with climate change. Our study demonstrated the importance of sampling standardization of the salinity range in estuaries for reliable analysis of pollution effects on biota.

  18. Anthropogenic Carbon Pump in an Urbanized Estuary

    NASA Astrophysics Data System (ADS)

    Park, J. H.; Yoon, T. K.; Jin, H.; Begum, M. S.

    2015-12-01

    The importance of estuaries as a carbon source has been increasingly recognized over the recent decades. However, constraining sources of CO2 evasion from urbanized estuaries remains incomplete, particularly in densely populated river systems receiving high loads of organic carbon from anthropogenic sources. To account for major factors regulating carbon fluxes the tidal reach of the Han River estuary along the metropolitan Seoul, characterization of organic carbon in the main stem and major urban tributaries were combined with continuous, submersible sensor measurements of pCO2 at a mid-channel location over a year and continuous underway measurements using a submersible sensor and two equilibrator sytems across the estuarine section receiving urban streams. Single-site continuous measurements exhibited large seasonal and diurnal variations in pCO2, ranging from sub-ambient air levels to exceptionally high values approaching 10,000 ppm. Diurnal variations of pCO2 were pronounced in summer and had an inverse relationship with dissolved oxygen, pointing to a potential role of day-time algal consumption of CO2. Cruise measurements displayed sharp pCO2 pulses along the confluences of urban streams as compared with relatively low values along the upper estuary receiving low-CO2 outflows from upstream dams. Large downstream increases in pCO2, concurrent with increases in DOC concentrations and fluorescence intensities indicative of microbially processed organic components, imply a translocation and subsequent dilution of CO2 carried by urban streams and/or fast transformations of labile C during transit along downstream reaches. The unique combination of spatial and temporal continuous measurements of pCO2 provide insights on estuarine CO2 pulses that might have resulted from the interplay between high loads of CO2 and organic C of anthropogenic origin and their priming effects on estuarine microbial processing of terrigenous and algal organic matter.

  19. Migratory Behavior and Survival of Juvenile Salmonids in the Lower Columbia River and Estuary in 2009

    SciTech Connect

    McMichael, Geoffrey A.; Harnish, Ryan A.; Bellgraph, Brian J.; Carter, Jessica A.; Ham, Kenneth D.; Titzler, P. Scott; Hughes, Michael S.

    2010-08-01

    The study reported herein was funded as part of the Anadromous Fish Evaluation Program, which is managed by the U.S. Army Corps of Engineers (USACE). The Anadromous Fish Evaluation Program study code is EST P 02 01: A Study of Salmonid Survival and Behavior through the Columbia River Estuary Using Acoustic Tags. The study was conducted by the Pacific Northwest National Laboratory (PNNL) and National Oceanic and Atmospheric Administration (NOAA) Fisheries for the USACE Portland District. Estimated survival of acoustic-tagged juvenile Chinook salmon and steelhead through the lower Columbia River and estuary in 2009 was lowest in the final 50 km of the estuary. Probability of survival was relatively high (>0.90) for yearling and subyearling Chinook salmon from the Bonneville Dam forebay (rkm 236) to Three-tree Point (rkm 49.6). Survival of juvenile Chinook salmon declined sharply through the lower 50 km of the estuary. Acoustic-tagged steelhead smolts did not survive as well as juvenile Chinook salmon between Bonneville Dam and the mouth of the Columbia River. Steelhead survival began to decline farther upstream (at rkm 86) relative to that of the Chinook salmon stocks. Subyearling Chinook salmon survival decreased markedly as the season progressed. It remains to be determined whether later migrating subyearling Chinook salmon are suffering increasing mortality as the season progresses or whether some portion of the apparent loss is due to fish extending their freshwater residence. This study provided the first glimpse into what promises to be a very informative way to learn more about how juvenile salmonid passage experiences through the FCRPS may influence their subsequent survival after passing Bonneville Dam. New information regarding the influence of migration pathway through the lower 50 km of the Columbia River estuary on probability of survival of juvenile salmonids, combined with increased understanding regarding the foraging distances and time periods of

  20. Flow Liner Slot Edge Replication Feasibility Study

    NASA Technical Reports Server (NTRS)

    Newman, John A.; Willard, Scott A.; Smith, Stephen W.; Piascik, Robert S.

    2006-01-01

    Surface replication has been proposed as a method for crack detection in space shuttle main engine flowliner slots. The results of a feasibility study show that examination of surface replicas with a scanning electron microscope can result in the detection of cracks as small as 0.005 inch, and surface flaws as small as 0.001 inch, for the flowliner material.

  1. Mercury in sediments of Ulhas estuary.

    PubMed

    Ram, Anirudh; Rokade, M A; Borole, D V; Zingde, M D

    2003-07-01

    Hg levels in water, suspended particulate matter and sediment of the Ulhas estuary are under considerable environmental stress due to the indiscriminate release of effluents from a variety of industries including chlor-alkali plants. Concentration ranges of dissolved (0.04-0.61 micro gl(-1)) and particulate (1.13-6.43 micro gg(-1)) Hg reveal a definite enhancement of levels in the estuary. The Hg burden in sediment upstream of the weir that limits the tidal influence is low (0.08-0.19 micro gg(-1)) with low C(org) content (1.8-2.9%). The high Hg content of the sediment just below the weir varies seasonally (highest concentration recorded being 38.45 micro gg(-1)) due to incremental accretion of sediment as the fresh water flow over the weir progressively decreases. The 30 km segment of the estuary sustains markedly high levels of Hg in the sediment with an exponential decrease in the seaward direction from the weir. Higher concentrations than the expected background prevail in all the estuarine cores up to the bottom, though the overall concentration decreases from about 20 micro gg(-1) in core 7 (inner estuary) to 1 micro gg(-1) in core 31 (outer estuary). The Hg in sediment is associated with C(org), while its correlation with Al, Fe and Mn is poor. The Hg profiles in cores from the Arabian Sea (stations 34, 35 and 37) have a distinct horizon of enhanced concentration in the 5-60 cm segment. Based on 210Pb dating of core 37, the sediment at the bottom of this core is inferred to have been deposited in the year 1949, roughly two year prior to the establishment of the first chlor-alkali plant and represents the background (0.06-0.10 micro gg(-1)). The Hg profiles in the offshore cores indicate a marked increase in transfer of Hg to sediment subsequent to 1980, with a peak around 1990-1992. Based on the index of geoaccumulation it is considered that the estuarine segment between stations 4 and 23 is extremely polluted, while the sediment from the open coast is

  2. Freshwater, tidal and wave influences on a small estuary

    NASA Astrophysics Data System (ADS)

    Uncles, R. J.; Stephens, J. A.; Harris, C.

    2014-10-01

    Observations are presented of water levels, currents, salinity, turbidity, sediment grain sizes and sediment transport in the Devonshire Avon Estuary, UK, in order to improve knowledge of freshwater, wave and tidal influences on small, strongly tidal ría estuaries. A large reduction in tidal range occurred progressing from the coastal zone to the upper estuary that was mainly a consequence of rising bed and river water levels. The spring-neap cycle also had an influence on the reduction in tidal range along the length of the estuary. Surface gravity waves were completely dissipated propagating into the estuarine channel from the coastal zone, and despite strong wave-induced resuspension, suspended sediment was not transported into the lower estuary in observable amounts during the ensuing flood tide, indicating that the wave-suspended material was too coarse to remain in suspension once transported away from the surf zone. Turbidity in the lower estuary was relatively low during low runoff summer conditions and had largest values over low water, when turbid waters from farther up-estuary had been transported there. Strong resuspension events occurred at peak currents in the upper estuary during summer, reflecting the presence of finer-grained sediment sources. Turbidity was similar but greater in the lower estuary during high runoff winter conditions and strong resuspension occurred at peak currents, indicating an easily erodible, nearby sediment source, due to down-estuary movement and relocation of finer sediment over the winter. A large shoal in the lower estuary exhibited a consistent pattern of accretion/erosion during the high runoff months of late autumn and winter to spring that also was qualitatively consistent with sediment transport modelling and implied: (a), erosion from the up-estuary limit of the shoal with (b), down-estuary bed-load and suspended-load transport that accreted the centre and down-estuary limit of the shoal until (c), a diminished

  3. Particle-size evidence of estuary evolution: A rapid and diagnostic tool for determining the nature of recent saltmarsh accretion

    NASA Astrophysics Data System (ADS)

    Rahman, Rubina; Plater, Andrew J.

    2014-05-01

    A conceptual model of saltmarsh sedimentation based on high-resolution particle-size analysis has been tested on short cores (c. 0.5 m) of known age from the Dee estuary, NW England, UK. Here, two components of the particle-size distribution (PSD) are interpreted as the traction load deposited by the faster tidal flow velocities ('fast tide') and the suspension load that settles during the turn of the tide ('slow tide'). The feasibility of this model for diagnosing the driving mechanism of estuary evolution in both time and space is tested with reference to historical evidence of saltmarsh accretion, up-core trends in dated saltmarsh cores, and the PSDs of present-day saltmarsh surface sediments. Cores that show an up-core progression from very fine-skewed to near symmetrical PSDs are interpreted in the context of estuary infilling due to a positive sediment budget (sediment surplus), whilst those that show a persistence of near-symmetrical, (very) poorly sorted, mesokurtic particle-size distributions in the fine to very fine silts size range are considered to be the result of 'slow tide' sedimentation. The influences of the two 'end-member' styles of saltmarsh accretion, i.e. (i) infilling due to sediment surplus and (ii) 'slow tide' settling linked to sea level, exhibit spatial and temporal trends as predicted, particularly in cores from mid- and lower saltmarsh locations. The upper saltmarsh cores also show evidence of estuary infilling due to 'slow tide' sedimentation at rates in excess of sea-level rise. The results confirm that the diagnostic approach can be applied as a 'pre-filtering' method for assessing the suitability of saltmarsh sediments for reconstructing sea-level trends, and for providing input data for improved estuary morphological modelling.

  4. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2006

    SciTech Connect

    Johnson, Gary E.; Borde, Amy B.; Dawley, Earl; Diefenderfer, Heida L.; Ebberts, Blaine D.; Putman, Douglas A.; Roegner, G. C.; Thom, Ronald M.; Vavrinec, John; Whiting, Allan H.

    2007-12-06

    This report is the third annual report of a six-year project to evaluate the cumulative effects of habitat restoration action in the Columbia River Estuary (CRE). The project is being conducted for the U.S. Army Corps of Engineers (Corps) by the Marine Sciences Laboratory of the Pacific Northwest National Laboratory, the Pt. Adams Biological Field Station of the National Marine Fisheries Service, and the Columbia River Estuary Study Taskforce. Measurement of the cumulative effects of ecological restoration projects in the Columbia River estuary is a formidable task because of the size and complexity of the estuarine landscape and the meta-populations of salmonids in the Columbia River basin. Despite the challenges presented by this system, developing and implementing appropriate indicators and methods to measure cumulative effects is the best way to enable estuary managers to track the overall effectiveness of investments in estuarine restoration projects. This project is developing methods to quantify the cumulative effects of multiple restoration activities in the CRE. The overall objectives of the 2006 study were to continue to develop techniques to assess cumulative effects, refine the standard monitoring protocols, and initiate development of an adaptive management system for Corps of Engineers’ habitat restoration monitoring efforts in the CRE. (The adaptive management effort will be reported at a later date.) Field studies during 2006 were conducted in tidal freshwater at Kandoll Farm on the lower Grays River and tidal brackish water at Vera Slough on Youngs Bay. Within each of area, we sampled one natural reference site and one restoration site. We addressed the overall objectives with field work in 2006 that, coupled with previous field data, had specific objectives and resulted in some important findings that are summarized here by chapter in this report. Each chapter of the report contains data on particular monitored variables for pre- and post

  5. Role and value of nitrogen regulation provided by oysters (Crassostrea virginica) in the Mission-Aransas Estuary, Texas, USA.

    PubMed

    Beseres Pollack, Jennifer; Yoskowitz, David; Kim, Hae-Cheol; Montagna, Paul A

    2013-01-01

    Suspension-feeding activities of oysters impart a potentially significant benefit to estuarine ecosystems via reduction of water column nutrients, plankton and seston biomass, and primary productivity which can have a significant impact on human well-being. This study considered nitrogen regulation by eastern oysters Crassostrea virginica in the Mission-Aransas Estuary, Texas, USA, as a function of denitrification, burial, and physical transport from the system via harvest. Oyster reefs were estimated to remove 502.5 kg N km(-2) through denitrification of biodeposits and 251.3 kg N km(-2) in burial of biodeposits to sediments. Nitrogen is also physically transported out of the estuary via harvest of oysters. Commercial harvest of oysters in the Mission-Aransas Estuary can remove approximately 21,665 kg N per year via physical transport from the system. We developed a transferable method to value the service of nitrogen regulation by oysters, where the potential cost equivalent value of nitrogen regulation is quantified via cost estimates for a constructed biological nutrient removal (BNR) supplement to a wastewater treatment plant. The potential annual engineered cost equivalent of the service of nitrogen regulation and removal provided by reefs in the Mission-Aransas Estuary is $293,993 yr(-1). Monetizing ecosystem services can help increase awareness at the stakeholder level of the importance of oysters beyond commercial fishery values alone.

  6. The Oncor Geodatabase for the Columbia Estuary Ecosystem Restoration Program: Annual Report, 2012

    SciTech Connect

    Coleman, Andre M.; Johnson, Gary E.; Borde, Amy B.; Diefenderfer, Heida L.; Sather, Nichole K.; Seiple, Timothy E.; Serkowski, John A.

    2013-11-10

    Pacific Northwest National Laboratory (PNNL) conducted this project for the U.S. Army Corps of Engineers, Portland District (Corps). The purpose of the project is to develop a geospatial, web-accessible database (called “Oncor”) for action effectiveness and related data from monitoring and research efforts for the Columbia Estuary Ecosystem Restoration Program (CEERP). The intent is for the Oncor database to enable synthesis and evaluation, the results of which can then be applied in subsequent CEERP decision-making. This is the first annual report in what is expected to be a 3- to 4-year project, which commenced on February 14, 2012.

  7. Trace metal concentrations in estuaries and coastal regions

    SciTech Connect

    Hunt, C.D.

    1994-12-31

    Estuaries and coastal regions are highly variable in the physical and hydrographic conditions. As a result of heavy urbanization and industrialization of the head waters of most estuaries, there are substantial localized inputs of contaminants to the estuary. These factors combined with the flushing characteristics of individual estuaries to create relatively unique features that result in variation in the typical levels of trace metals for these systems. This makes intercomparison of the estuaries difficult. Comparability among estuaries becomes even more difficult when metals analyses are conducted without proper control of field and laboratory contamination, now firmly established in the trace metal analytical literature as a prerequisite for reliable marine trace metals analysis. This paper compares the concentrations of selected trace metal (Ag, Cd, Cu, Ni, Pb, and Zn) concentrations in the waters of several major estuaries of the United States. The basis of comparison is that all samples war collected under rigid trace metal clean collection and analysis procedures. Generally, metal concentrations within the estuaries are similar. Metal concentrations in the higher salinity coastal regions are more similar in concentration. The comparison provides a baseline of typical concentrations of these trace metals in the coastal waters against which future analytical results can be compared.

  8. Collaborative Potential between National Estuary Programs and Coastal EPA Laboratories

    EPA Science Inventory

    Estuaries are among the most productive ecosystems in the world, providing unique habitat for freshwater and marine species as well as valuable social and economic benefits. The wealth of ecosystem goods and services from estuaries has led to growth and development of human commu...

  9. Identifying and organizing objectives across the 28 National Estuary Programs

    EPA Science Inventory

    The National Estuary Program (NEP), established in 1987 by amendments to the Clean Water Act, is intended to support local communities to restore, protect and manage estuaries of national significance. Currently there a 28 NEPs spread widely across the U.S. and its territories. E...

  10. Macroalgae, pore water sulfides and eelgrass in Yaquina estuary, Oregon

    EPA Science Inventory

    The hypothesis that relatively high nutrients in estuaries of the Pacific Northwest (PNW) can lead to eutrophication and degradation of critical eelgrass habitat was examined. Yaquina estuary was surveyed for cover and above-ground biomass of benthic macroalgae (Ulva spp.) and n...

  11. INDEX OF ESTUARINE BENTHIC INTEGRITY FOR GULF OF MEXICO ESTUARIES

    EPA Science Inventory

    A benthic index for northern Gulf of Mexico estuaries has been developed and successfully validated by the Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) in the Louisianian Province. The benthic index is a useful indicator of estuarine condition that provi...

  12. ASSESSING THE ECOLOGICAL CONDITION OF SOUTHEAST U. S. ESTUARIES

    EPA Science Inventory

    As a means to assess ecological condition, 151 stations located in southeastern estuaries from Cape Henry, Virginia to Biscayne Bay, Florida were sampled by state agencies during the summer of 2000 using a probabilistic design. The design used 8 size classes of estuaries ranging ...

  13. Fortnightly Variability At The Transition Between Two Sub-Estuaries

    NASA Astrophysics Data System (ADS)

    Riveron-Enzastiga, M. L.; Valle-Levinson, A.

    2007-05-01

    Profiles of current velocity from an Acoustic Doppler Current Profiler (ADCP) and of water salinity, temperature and density from a Conductivity-Temperature-Depth (CTD) recorder, were combined with surface salinity, temperature and density from a Conductivity-Temperature (CT) recorder to elucidate the fortnightly variability at the Lafayette River entrance. The Lafayette River connects at its mouth with the Elizabeth River, which is a tributary to the James River in the Chesapeake Bay. Data were collected in four experiments during consecutive spring and neap tides in the autumn of 2000, and in the spring of 2001. Each experiment was carried out for ~25 hours and consisted of three across-estuary transects: one at the mouth, where the Elizabeth River estuary influences the Lafayette River estuary, and two more toward the head of the estuary. The maximum depth of the transects was <5 m, and despite the shallowness, the mean flow showed two-layer exchange during neap tides. During spring tides there was an evident recirculation where the two sub-estuaries interact and a marked lateral density structure. During neap tides, there was a recirculation consisting of inflow in the northern half of the estuary and net outflow at the surface and net inflow at the bottom in the southern half of the estuary. The recirculation at the mouth is intensified during wet periods due to intense river discharge. The along-estuary dynamics is that proposed by the theory, between pressure gradient and friction.

  14. YAQUINA BAY AND BEYOND: WHAT SHAPE ARE OUR ESTUARIES IN?

    EPA Science Inventory

    The great natural beauty of Oregon's estuaries gives an impression of systems that are far less altered than those in other areas of the US. However, over the years, Yaquina Bay and other western estuaries have been variously affected by habitat loss and alteration, over harvest...

  15. Nitrogen Source and Loading Data for EPA Estuary Data Mapper

    EPA Science Inventory

    Nitrogen source and loading data have been compiled and aggregated at the scale of estuaries and associated watersheds of the conterminous United States, using the spatial framework in EPA's Estuary Data Mapper (EDM) to provide system boundaries. Original sources of data include...

  16. WATER QUALITY MODELING IN THE RIO CHONE ESTUARY

    EPA Science Inventory

    Water quality in the Rio Chone Estuary, a seasonally inverse, tropical estuary, in Ecuador was characterized by modeling the distribution of biochemical oxygen demand (BOD) and dissolved inorganic nitrogen (DIN) within the water column. These two variables are modeled using modif...

  17. Approaches for Development of Nutrient Criteria in Oregon Estuaries With a Focus on Tillamook Estuary

    EPA Science Inventory

    Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

  18. Policy development and the estuary environment: a Severn Estuary case study.

    PubMed

    Ballinger, R; Stojanovic, T

    2010-01-01

    The paper reviews the development of key policy relating to estuary management, highlighting the trends and drivers in policy development which have shaped the management and protection of the estuary environment. Focusing on policy developments over the last three decades, the paper draws attention to the significant influence of European policy and new approaches to environmental governance in stimulating wider and more integrated approaches to the environmental management of the estuary, as well as highlighting considerable environmental improvements associated with increased environmental regulation. The paper discusses how 'fit for purpose' the policy framework is to address current challenges, including those identified by recent stakeholder consultations. Significant issues include limited understanding and information related to the cause-effect relationships between policy and environmental quality as well as ongoing institutional and policy fragmentation associated with devolutionary processes. Such fragmentation, alongside under-investment in integrated estuary planning, is likely to prove a particular challenge to balanced and informed decision-making. Whilst the paper focuses on the Severn experience, the approach adopted will be of interest to all assessing policy-environment linkages.

  19. Conditions for tidal bore formation in convergent alluvial estuaries

    NASA Astrophysics Data System (ADS)

    Bonneton, Philippe; Filippini, Andrea Gilberto; Arpaia, Luca; Bonneton, Natalie; Ricchiuto, Mario

    2016-04-01

    Over the last decade there has been an increasing interest in tidal bore dynamics. However most studies have been focused on small-scale bore processes. The present paper describes the first quantitative study, at the estuary scale, of the conditions for tidal bore formation in convergent alluvial estuaries. When freshwater discharge and large-scale spatial variations of the estuary water depth can be neglected, tide propagation in such estuaries is controlled by three main dimensionless parameters: the nonlinearity parameter ε0 , the convergence ratio δ0 and the friction parameter ϕ0. In this paper we explore this dimensionless parameter space, in terms of tidal bore occurrence, from a database of 21 estuaries (8 tidal-bore estuaries and 13 non tidal-bore estuaries). The field data point out that tidal bores occur for convergence ratios close to the critical convergence δc. A new proposed definition of the friction parameter highlights a clear separation on the parameter plane (ϕ0,ε0) between tidal-bore estuaries and non tidal-bore estuaries. More specifically, we have established that tidal bores occur in convergent estuaries when the nonlinearity parameter is greater than a critical value, εc , which is an increasing function of the friction parameter ϕ0. This result has been confirmed by numerical simulations of the two-dimensional Saint Venant equations. The real-estuary observations and the numerical simulations also show that, contrary to what is generally assumed, tide amplification is not a necessary condition for tidal bore formation. The effect of freshwater discharge on tidal bore occurrence has been analyzed from the database acquired during three long-term campaigns carried out on the Gironde/Garonne estuary. We have shown that in the upper estuary the tidal bore intensity is mainly governed by the local dimensionless tide amplitude ε. The bore intensity is an increasing function of ε and this relationship does not depend on freshwater

  20. Global patterns and predictors of fish species richness in estuaries.

    PubMed

    Vasconcelos, Rita P; Henriques, Sofia; França, Susana; Pasquaud, Stéphanie; Cardoso, Inês; Laborde, Marina; Cabral, Henrique N

    2015-09-01

    1. Knowledge of global patterns of biodiversity and regulating variables is indispensable to develop predictive models. 2. The present study used predictive modelling approaches to investigate hypotheses that explain the variation in fish species richness between estuaries over a worldwide spatial extent. Ultimately, such models will allow assessment of future changes in ecosystem structure and function as a result of environmental changes. 3. A comprehensive worldwide data base was compiled of the fish assemblage composition and environmental characteristics of estuaries. Generalized Linear Models were used to quantify how variation in species richness among estuaries is related to historical events, energy dynamics and ecosystem characteristics, while controlling for sampling effects. 4. At the global extent, species richness differed among marine biogeographic realms and continents and increased with mean sea surface temperature, terrestrial net primary productivity and the stability of connectivity with a marine ecosystem (open vs. temporarily open estuaries). At a smaller extent (within a marine biogeographic realm or continent), other characteristics were also important in predicting variation in species richness, with species richness increasing with estuary area and continental shelf width. 5. The results suggest that species richness in an estuary is defined by predictors that are spatially hierarchical. Over the largest spatial extents, species richness is influenced by the broader distributions and habitat use patterns of marine and freshwater species that can colonize estuaries, which are in turn governed by history contingency, energy dynamics and productivity variables. Species richness is also influenced by more regional and local parameters that can further affect the process of community colonization in an estuary including the connectivity of the estuary with the adjacent marine habitat, and, over smaller spatial extents, the size of these

  1. AN APPROACH TO DEVELOPING NUTRIENT CRITERIA FOR PACIFIC NORTHWEST ESTUARIES: A CASE STUDY OF YAQUINA ESTUARY, OREGON

    EPA Science Inventory

    NHEERL scientists have developed an approach that could be used by the State of Oregon for development of nutrient and other water quality criteria for the Yaquina Estuary, Oregon. The principle objective in setting protective criteria is to prevent future degradation of estuari...

  2. Phosphorous dynamics in a temperate intertidal estuary

    NASA Astrophysics Data System (ADS)

    Lillebø, A. I.; Neto, J. M.; Flindt, M. R.; Marques, J. C.; Pardal, M. A.

    2004-09-01

    Conservation and management of aquatic systems require detailed information of the processes that affect their functioning and development. The objectives of the present work were to describe the phosphorus dynamics during a complete tidal cycle and to quantify the relative contribution of the most common estuarine areas (e.g. seagrass beds, salt marshes, mud- and sand-flats without vegetation) to phosphorus net internal loading in a temperate intertidal estuary. Results show that phosphate efflux rates were higher during the first hours of tidal flood, and that phosphate concentrations were lowest at high tide. During tidal ebbing, ephemeral tide pools may cover a considerable percentage of the intertidal area. In these tide pools, water shallowness combined with enhanced temperatures stimulate the occurrence of high phosphate effluxes. The effluxes to the main water body during high tide contributed 57% of dissolved inorganic phosphorus and efflux during low tide contributed 43% to the net internal loading. Calculations of the phosphate net effluxes (kg P) indicate a strong contribution of the bare bottom mud-flats to the whole system internal phosphate loading, especially during the warmer periods. As a consequence of eutrophication, perennial benthic macrophytes are commonly replaced by fast-growing epiphytic macroalgae. Calculations showed that for a hypothetical intertidal estuary in a temperate region, management programs considering an eventual re-colonization of mud-flats by seagrasses or salt marsh plants may reduce the P-efflux by 13-16 kg ha -1. For example, in the small Mondego estuary, eutrophication has contributed to a reduction of the Zostera noltii meadows, leading to an increase in 190 kg of phosphorus net internal loading.

  3. Latest Holocene evolution and human disturbance of a channel segment in the Hudson River Estuary

    USGS Publications Warehouse

    Klingbeil, A.D.; Sommerfield, C.K.

    2005-01-01

    River Estuary changed rapidly in response to engineering works that forced the channel to self-deepen. Analysis of historical bathymetric data indicates that the channel lost an estimated 3 ?? 106 tons of sediment between ca. 1939 and 2002 (50,000 tons/yr average) by subaqueous erosion, increasing in depth by as much as 4 m in places. Erosion appears to have been concurrent with systematic bulkheading of the shoreline after ca. 1865, which decreased the estuary surface area by ??? 19% overall. Evidently, self-deepening of the channel is a morphodynamic adjustment to reestablish equilibrium cross-sectional area, yet the state of this change locally and elsewhere in the estuary is unknown. Subaqueous erosion documented in this study is a significant source of sediment with implications to the sediment budget and environmental quality of the Hudson River Estuary. ?? 2005 Elsevier B.V. All rights reserved.

  4. Near coastal program plan for 1991: Estuaries

    SciTech Connect

    Not Available

    1990-11-01

    Environmental regulatory programs in the United States have been estimated to cost more than $70 billion annually. The Environmental Monitoring and Assessment Program (EMAP) is a nationwide initiative being implemented by EPA's Office of Research and Development (ORD). It was developed in response to the demand for information on the condition of the nation's ecological resources. The goal of EMAP is to assess and document the status and trends in the condition of the nation's forests, wetlands, estuaries, coastal waters, lakes, rivers, and streams, Great Lakes, agricultural lands, and arid lands on an integrated and continuing basis.

  5. 14-plex Feasibility Report

    SciTech Connect

    Kotongan, Victoria Hazel

    2013-06-21

    The Native Village of Unalakleet project was a feasibility study for a retrofit of a “tribally owned” three story, 14 apartment complex located in Unalakleet, Alaska. The program objective and overall goal was to create a plan for retrofitting to include current appraised value and comparable costs of new construction to determine genuine feasibility as low-income multi-family housing for tribal members.

  6. Ecological Engineering Practices for the Reduction of Excess Nitrogen in Human-Influenced Landscapes: A Guide for Watershed Managers

    EPA Science Inventory

    Excess nitrogen (N) in freshwater systems, estuaries, and coastal areas has well-documented deleterious effects on ecosystems. Ecological engineering practices (EEPs) may be effective at decreasing nonpoint source N leaching to surface and groundwater. However, few studies have s...

  7. Facilitation of the Estuary/Ocean Subgroup and the Expert Regional Technical Group, Annual Report for 2015

    SciTech Connect

    Johnson, Gary E.

    2015-08-01

    This document is the annual report for the period September 1, 2014 through August 31, 2015 for the project—Facilitation of the Estuary/Ocean Subgroup (EOS) and the Expert Regional Technical Group (ERTG). Pacific Northwest National Laboratory (PNNL) conducted the project for the Bonneville Power Administration (BPA). The EOS and ERTG are part of the research, monitoring, and evaluation (RME) and habitat restoration efforts, respectively, developed by the Action Agencies (BPA, U.S. Army Corps of Engineers [Corps or USACE], and U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS) and implemented under the Columbia Estuary Ecosystem Restoration Program (CEERP). BPA/Corps (2015) explain the CEERP and the role of RME and the ERTG. For the purposes of this report, the lower Columbia River and estuary (LCRE) includes the floodplain from Bonneville Dam down through the lower river and estuary into the river’s plume in the ocean. The main purpose of this project is to facilitate EOS and ERTG meetings and work products. Other purposes are to provide technical support for CEERP adaptive management, CEERP restoration design challenges, and tributary RME. From 2002 through 2008, the EOS worked to design the federal RME program for the estuary/ocean (Johnson et al. 2008). From 2009 to the present day, EOS activities have involved RME implementation; however, EOS activities were minimal during the current reporting period. PNNL provided technical support to CEERP’s adaptive management process by convening 1.2 meetings of the Action Agencies (AAs) and drafting material for the “CEERP 2015 Restoration and Monitoring Plan” (BPA/Corps 2015).

  8. Change in Land Cover along the Lower Columbia River Estuary as Determined from Landsat Thematic Mapper (TM) Imagery, Technical Report 2003.

    SciTech Connect

    Garono, Ralph; Anderson, Becci; Robinson, Rob

    2003-10-01

    The Lower Columbia River Estuary Management Plan (Jerrick, 1991) recognizes the positive relationship between the conservation of fish and wildlife habitat, and sustaining their populations. An important component of fish and wildlife conservation and management is the identification of habitats, trends in habitat change, and delineation of habitat for preservation, restoration or enhancement. Alterations to the environment, such as hydropower generation, dredging, forestry, agriculture, channel alteration, diking, bank stabilization and floodplain development, have dramatically altered both the type and distribution of habitats along the Columbia River Estuary (CRE) and its floodplain. Along the Columbia River, tidally influenced habitats occur from the river mouth to the Bonneville Dam, a distance of 230 km. If we are to effectively manage the natural resources of the Columbia River ecosystem, there is a need to understand how habitats have changed because fish and wildlife populations are known to respond to changes in habitat quality and distribution. The goal of this study was to measure the amount and type of change of CRE land cover from 1992 to 2000. We performed a change analysis on two spatial data sets describing land cover along the lower portion of the estuary (Fig. 1). The 1992 data set was created by the NOAA Coastal Remote Sensing, Coastal Change Analysis Program (C-CAP) in cooperation with Columbia River Estuary Study Task Force (CREST), the National Marine Fisheries Service (NMFS) Point Adams Field Station, and State of Washington Department of Natural Resources (DNR). The 2000 data set was produced by Earth Design Consultants, Inc. (EDC) and the Wetland Ecosystem Team (WET: University of Washington) as part of a larger Lower Columbia River Estuary Partnership (Estuary Partnership) habitat mapping study. Although the image classification methodologies used to create the data sets differed, both data sets were produced by classifying Landsat

  9. Geographic signatures of North American West Coast estuaries

    USGS Publications Warehouse

    Emmett, Robert; Llansó, Roberto; Newton, Jan; Thom, Ron; Hornberger, Michelle; Morgan, Cheryl; Levings, Colin; Copping, Andrea; Fishman, Paul

    2000-01-01

    West Coast estuaries are geologically young and composed of a variety of geomorphological types. These estuaries range from large fjords to shallow lagoons; from large to low freshwater flows. Natural hazards include E1 Niños, strong Pacific storms, and active tectonic activity. West Coast estuaries support a wide range of living resources: five salmon species, harvestable shellfish, waterfowl and marine birds, marine mammals, and a variety of algae and plants. Although populations of many of these living resources have declined (salmonids), others have increased (marine mammals). West Coast estuaries are also centers of commerce and increasingly large shipping traffic. The West Coast human population is rising faster than most other areas of the U.S. and Canada, and is distributed heavily in southern California, the San Francisco Bay area, around Puget Sound, and the Fraser River estuary. While water pollution is a problem in many of the urbanized estuaries, most estuaries do not suffer from poor water quality. Primary estuarine problems include habitat alterations, degradation, and loss; diverted freshwater flows; marine sediment contamination; and exotic species introductions. The growing West Coast economy and population are in part related to the quality of life, which is dependent on the use and enjoyment of abundant coastal natural resources.

  10. Scavenging Rate Ecoassay: A Potential Indicator of Estuary Condition

    PubMed Central

    Porter, Augustine G.; Scanes, Peter R.

    2015-01-01

    Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress. PMID:26024225

  11. Scavenging rate ecoassay: a potential indicator of estuary condition.

    PubMed

    Porter, Augustine G; Scanes, Peter R

    2015-01-01

    Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress.

  12. [Vulnerability assessment on the coastal wetlands in the Yangtze Estuary under sea-level rise].

    PubMed

    Cui, Li-Fang; Wang, Ning; Ge, Zhen-Ming; Zhang, Li-Quan

    2014-02-01

    To study the response of coastal wetlands to climate change, assess the impacts of climate change on the coastal wetlands and formulate feasible and practical mitigation strategies are the important prerequisite for securing coastal ecosystems. In this paper, the possible impacts of sea level rise caused by climate change on the coastal wetlands in the Yangtze Estuary were analyzed by the Source-Pathway-Receptor-Consequence (SPRC) model and IPCC definition on the vulnerability. An indicator system for vulnerability assessment was established, in which sea-level rise rate, subsidence rate, habitat elevation, inundation threshold of habitat and sedimentation rate were selected as the key indicators. A quantitatively spatial assessment method based on the GIS platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability index for the assessment of coastal wetlands in the Yangtze Estuary under the scenarios of sea-level rise. The vulnerability assessments on the coastal wetlands in the Yangtze Estuary in 2030 and 2050 were performed under two sea-level rise scenarios (the present sea-level rise trend over recent 30 years and IPCC A1F1 scenario). The results showed that with the projection in 2030 under the present trend of sea-level rise (0.26 cm x a(-1)), 6.6% and 0.1% of the coastal wetlands were in the low and moderate vulnerabilities, respectively; and in 2050, 9.8% and 0.2% of the coastal wetlands were in low and moderate vulnerabilities, respectively. With the projection in 2030 under the A1F1 scenario (0.59 cm x a(-1)), 9.0% and 0.1% of the coastal wetlands were in the low and moderate vulnerabilities, respectively; and in 2050, 9.5%, 1.0% and 0.3% of the coastal wetlands were in the low, moderate and high vulnerabilities, respectively.

  13. Structure and Function of South-east Australian Estuaries

    NASA Astrophysics Data System (ADS)

    Roy, P. S.; Williams, R. J.; Jones, A. R.; Yassini, I.; Gibbs, P. J.; Coates, B.; West, R. J.; Scanes, P. R.; Hudson, J. P.; Nichol, S.

    2001-09-01

    An attempt is made to synthesize the geological properties, water quality attributes and aspects of the ecology of south-east Australian estuaries so as to provide a framework for addressing coastal management issues. The approach is based on the underlying causal factors of geology and morphology and more immediate environmental factors (e.g. salinity and sediments) which are associated with ecological distributions, species richness and fisheries catch. This ' broad brush ' approach seeks to maximize reality and generality, albeit at the expense of precision and local variability in individual circumstances. It disregards small-scale ecological patterns as noise. Unlike in the Northern Hemisphere, conditions in temperate Australia are characterized by irregular flood and fire regimes that strongly influence estuary hydrology and nutrient inputs. Three main types of estuary (tide-dominated, wave-dominated and intermittently closed) are recognized based on geological criteria and having particular entrance conditions that control tidal exchange. Four zones (marine flood-tidal delta, central mud basin, fluvial delta and riverine channel/alluvial plain) are also recognized common to each type of estuary. These zones correspond to mappable sedimentary environments in all estuaries and have characteristic water quality, nutrient cycling/primary productivity signatures and ecosystems. The ecology of a zone is modified by (a) estuary type which determines the salinity regime; (b) stage of sediment filling (evolutionary maturity) which controls the spatial distribution/size of the zones; and (c) impacts of various forms of development. By using the zones/habitats as a common currency among all estuaries, it is possible to link ecological aspects such as species richness and commercial fisheries production so as to compare different estuaries or within-estuary zones.

  14. United States Air Force 611th Air Support Group/Civil Engineering Squadron, Elmendorf AFB, Alaska. Remedial investigation and feasibility study: Oliktok Point Radar Installation, Alaska. Volume 1. (Includes appendices a - b)

    SciTech Connect

    1996-04-15

    This report presents the findings of Remedial Investigations and Feasibility Studies at sites located at the Oliktok Point radar installation in northern Alaska. The sites were characterized based on sampling and analyses conducted during Remedial Investigation activities performed during August and September 1993.

  15. From the utilization point of view, the two approaches seem to United States Air Force 611th Air Support Group/Civil Engineering Squadron, Elmendorf AFB, Alaska. Remedial investigation and feasibility study Point Barrow Radar Installation, Alaska. Final report

    SciTech Connect

    Karmi, S.

    1996-02-19

    This report presents the findings of Remedial Investigations and Feasibility Studies at sites located at the Point Barrow radar installation in northern Alaska. The sites were characterized based on sampling and analyses conducted during Remedial Investigation activities performed during August and September 1993.

  16. Multi-Scale Action Effectiveness Research in the Lower Columbia River and Estuary, 2011 - FINAL ANNUAL REPORT

    SciTech Connect

    Sather, Nichole K.; Storch, Adam; Johnson, Gary E.; Teel, D. J.; Skalski, J. R.; Bryson, Amanda J.; Kaufmann, Ronald M.; Woodruff, Dana L.; Blaine, Jennifer; Kuligowski, D. R.; Kropp, Roy K.; Dawley, Earl M.

    2012-05-31

    The study reported here was conducted by researchers at Pacific Northwest National Laboratory (PNNL), the Oregon Department of Fish and Wildlife (ODFW), the University of Washington (UW), and the National Marine Fisheries Service (NMFS) for the U.S. Army Corps of Engineers, Portland District (USACE). This research project was initiated in 2007 by the Bonneville Power Administration to investigate critical uncertainties regarding juvenile salmon ecology in shallow tidal freshwater habitats of the lower Columbia River. However, as part of the Washington Memorandum of Agreement, the project was transferred to the USACE in 2010. In transferring from BPA to the USACE, the focus of the tidal freshwater research project shifted from fundamental ecology toward the effectiveness of restoration in the Lower Columbia River and estuary (LCRE). The research is conducted within the Action Agencies Columbia Estuary Ecosystem Restoration Program (CEERP). Data reported herein spans the time period May 2010 to September 2011.

  17. Estuary/ocean exchange and tidal mixing in a Gulf of Maine Estuary: A Lagrangian modeling study

    NASA Astrophysics Data System (ADS)

    Bilgili, Ata; Proehl, Jeffrey A.; Lynch, Daniel R.; Smith, Keston W.; Swift, M. Robinson

    2005-12-01

    A Lagrangian particle method embedded within a 2-D finite element code, is used to study the transport and ocean-estuary exchange processes in the well-mixed Great Bay Estuarine System in New Hampshire, USA. The 2-D finite element model, driven by residual, semi-diurnal and diurnal tidal constituents, includes the effects of wetting and drying of estuarine mud flats through the use of a porous medium transport module. The particle method includes tidal advection, plus a random walk model in the horizontal that simulates sub-grid scale turbulent transport processes. Our approach involves instantaneous, massive [O(500,000)] particle releases that enable the quantification of ocean-estuary and inter-bay exchanges in a Markovian framework. The effects of the release time, spring-neap cycle, riverine discharge and diffusion strength on the intra-estuary and estuary-ocean exchange are also investigated. The results show a rather dynamic interaction between the ocean and the estuary with a fraction of the exiting particles being caught up in the Gulf of Maine Coastal Current and swept away. Three somewhat different estimates of estuarine residence time are calculated to provide complementary views of estuary flushing. Maps of residence time versus release location uncover a strong spatial dependency of residence time within the estuary that has very important ramifications for local water quality. Simulations with and without the turbulent random walk show that the combined effect of advective shear and turbulent diffusion is very effective at spreading particles throughout the estuary relatively quickly, even at low (1 m 2/s) diffusivity. The results presented here show that a first-order Markov Chain approach has applicability and a high potential for improving our understanding of the mixing processes in estuaries.

  18. Causes and effects of a highly successful marine invasion: Case-study of the introduced Pacific oyster Crassostrea gigas in continental NW European estuaries

    NASA Astrophysics Data System (ADS)

    Troost, Karin

    2010-10-01

    Since the 1960's, the Pacific oyster Crassostrea gigas has been introduced for mariculture at several locations within NW Europe. The oyster established itself everywhere and expanded rapidly throughout the receiving ecosystems, forming extensive and dense reef structures. It became clear that the Pacific oyster induced major changes in NW European estuaries. This paper reviews the causes of the Pacific oyster's remarkably successful establishment and spread in The Netherlands and neighbouring countries, and includes a comprehensive review of consequences for the receiving communities. Ecosystem engineering by C. gigas and a relative lack of natural enemies in receiving ecosystems are identified as the most important characteristics facilitating the invader's successful establishment and expansion. The Pacific oyster's large filtration capacity and eco-engineering characteristics induced many changes in receiving ecosystems. Different estuaries are affected differently; in the Dutch Oosterschelde estuary expanding stocks saturate the carrying capacity whereas in the Wadden Sea no such problems exist. In general, the Pacific oyster seems to fit well within continental NW European estuarine ecosystems and there is no evidence that the invader outcompetes native bivalves. C. gigas induces changes in plankton composition, habitat heterogeneity and biodiversity, carrying capacity, food webs and parasite life cycles. The case of the Pacific oyster in NW European estuaries is only one example in an increasing series of biological invasions mediated by human activities. This case-study will contribute to further elucidating general mechanisms in marine invasions; invasions that sometimes appear a threat, but can also contribute to ecological complexity.

  19. Hydro-sedimentary processes of a shallow tropical estuary under Amazon influence. The Mahury Estuary, French Guiana

    NASA Astrophysics Data System (ADS)

    Orseau, Sylvain; Lesourd, Sandric; Huybrechts, Nicolas; Gardel, Antoine

    2017-04-01

    Along the Guianas coast, coastal dynamic is characterized by the migration of mud banks originating from the Amazon. This singular feature affects the dynamic and the morphology of local estuaries and can induce rapid bathymetric evolution in lower estuaries. Since 2012, the navigation channel of the Mahury Estuary (French Guiana) is enduring a severe siltation whose origin comes from a mud bank crossing the estuary mouth. This study aims to determine how the migration of a mud bank through an estuary mouth could influence the transport and fluxes in the estuary. Field measurements were performed over a year with the monitoring of the salt intrusion length, mooring surveys during spring-neap cycles and shipboard profiling surveys during semi-diurnal cycles. Salt intrusion lengths underline a significant seasonal variation characterized by the transition from a steady-state length during high river discharge and a wide range of lengths with the tidal range during low to moderate river discharge. During the rainy season, measurements indicate a fluvial-dominated condition with low suspended-sediment concentrations most of the semi-diurnal cycle. Residual sediment fluxes are usually seaward excepted when river discharge is below seasonal average. During the dry season, maximum suspended-sediment concentrations are higher in the middle part of the estuary. Residual sediment fluxes are landward along the estuary and stronger during neap tides in the estuary mouth and few kilometers upstream. In this area, a persistent density stratification traps sediments in the bottom layer and generates a gravitational circulation during neap tides, which enhances landward transports up to 2.56 t m-1 over a semi-diurnal cycle. In the middle estuary, landward fluxes are most significant during the dry season and also during the rainy season when the river discharge is below the seasonal average. Although this study includes temporal and spatial limitations, it underlines significant

  20. Ceramic automotive Stirling engine program

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The Ceramic Automotive Stirling Engine Program evaluated the application of advanced ceramic materials to an automotive Stirling engine. The objective of the program was to evaluate the technical feasibility of utilizing advanced ceramics to increase peak engine operating temperature, and to evaluate the performance benefits of such an increase. Manufacturing cost estimates were also developed for various ceramic engine components and compared with conventional metallic engine component costs.

  1. Ceramic Automotive Stirling Engine Program

    SciTech Connect

    Not Available

    1986-08-01

    The Ceramic Automotive Stirling Engine Program evaluated the application of advanced ceramic materials to an automotive Stirling engine. The objective of the program was to evaluate the technical feasibility of utilizing advanced ceramics to increase peak engine operating temperature, and to evaluate the performance benefits of such an increase. Manufacturing cost estimates were also developed for various ceramic engine components and compared with conventional metallic engine component costs.

  2. Use of the USEPA Estuary Nitrogen Model to Estimate Concentrations of Total Nitrogen in Estuaries Using Loads Calculated by Watershed Models and Monitoring Data

    EPA Science Inventory

    We use USEPA’s Estuary Nitrogen Model (ENM) to calculate annual average concentrations of total nitrogen (TN) in ten estuaries or sub-estuaries along the Atlantic coast from New Hampshire to Florida. These include a variety of systems, ranging from strongly-flushed bays to weakly...

  3. Assessing the impact of human activities on British Columbia's estuaries.

    PubMed

    Robb, Carolyn K

    2014-01-01

    The world's marine and coastal ecosystems are under threat and single-sector management efforts have failed to address those threats. Scientific consensus suggests that management should evolve to focus on ecosystems and their human, ecological, and physical components. Estuaries are recognized globally as one of the world's most productive and most threatened ecosystems and many estuarine areas in British Columbia (BC) have been lost or degraded. To help prioritize activities and areas for regional management efforts, spatial information on human activities that adversely affect BC's estuaries was compiled. Using statistical analyses, estuaries were assigned to groups facing related threats that could benefit from similar management. The results show that estuaries in the most populated marine ecosections have the highest biological importance but also the highest impacts and the lowest levels of protection. This research is timely, as it will inform ongoing marine planning, land acquisition, and stewardship efforts in BC.

  4. MODIS water quality algorithms for northwest Florida estuaries

    EPA Science Inventory

    Synoptic and frequent monitoring of water quality parameters from satellite is useful for determining the health of aquatic ecosystems and development of effective management strategies. Northwest Florida estuaries are classified as optically-complex, or waters influenced by chlo...

  5. Evaluating Causes of Ecological Impairments in the Estuaries of Ukraine

    EPA Science Inventory

    Ukrainian estuaries have not undergone a systematic evaluation of the causes of ecological impairments caused by anthropogenic contamination. The objective of this evaluation is to use recently developed diagnostic tools to determine the causes of benthic ecological impairments. ...

  6. A PROBABILISTIC SURVEY OF SEDIMENT TOXICITY IN WEST COAST ESTUARIES

    EPA Science Inventory

    A probabalistic survey of coastal condition assessment was conducted in 1999 by participants in US EPA's Environmental Monitoring and Assessment Program (EMAP). The survey targeted estuaries along the outer coasts of Washington, Oregon and California, including the lower Columbi...

  7. BACTERIOPLANKTON DYNAMICS IN A SUBTROPICAL ESTUARY: EVIDENCE FOR SUBSTRATE LIMITATION

    EPA Science Inventory

    Bacterioplankton abundance and metabolic characteristics were measured along a transect in Pensacola Bay, Florida, USA, to examine the factors that control microbial water column processes in this subtropical estuary. The microbial measures included 3 H-L-leucine incorporation, e...

  8. MAPPING BURROWING SHRIMP AND SEAGRASS IN YAQUINA ESTUARY

    EPA Science Inventory

    Burrowing shrimp and seagrasses create extensive intertidal and shallow subtidal habitats within Pacific NW estuaries. Maps of their populations are useful to inform estuarine managers of locations that deserve special consideration for conservation, and to inform oyster farmers...

  9. DOWNSTREAM MIGRATION OF SALMONID SMOLTS IN OREGON RIVERS AND ESTUARIES

    EPA Science Inventory

    Migratory fish passage is an important designated use for many Oregon estuaries. Acoustic transmitters were implanted in coho smolts in 2004 and 2006 to evaluate how estuarine habitat, and habitat loss, might affect population health. Acoustic receivers that identified individu...

  10. Estuary 2100 Project, Phase 2: Building Partnerships for Resilient Watersheds

    EPA Pesticide Factsheets

    Information about the SFBWQP Estuary 2100 Project, Phase 2: Building Partnerships for Resilient Watersheds, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquat

  11. How the National Estuary Programs Address Environmental Issues

    EPA Pesticide Factsheets

    Estuaries face many challenges including, alteration of natural hydrologic flows, aquatic nuisance species, climate change, declines in fish and wildlife populations, habitat loss and degradation, nutrient loads, pathogens, stormwater and toxics.

  12. HIGH CYANOBACTERIAL ABUNDANCE IN GULF OF MEXICO ESTUARIES

    EPA Science Inventory

    Aquatic phytoplankton comprise a wide variety of taxa spanning more than 2 orders of magnitude in size, yet studies of estuarine phytoplankton often overlook the picoplankton, particularly chroococcoid cyanobacteria (c.f. Synechocococcus). Three Gulf of Mexico estuaries (Apalachi...

  13. NEKTON-HABITAT ASSOCIATIONS IN A PACIFIC NORTHWEST (USA) ESTUARY

    EPA Science Inventory

    Nekton−habitat associations were determined in Yaquina Bay, Oregon, United States, using a stratified-by-habitat, random, estuary-wide sampling design. Three habitats (intertidal eelgrass [Zostera marina], mud shrimp [Upogebia pugettensis], and ghost shrimp [Neotrypaea californie...

  14. Environmental forcing on jellyfish communities in a small temperate estuary.

    PubMed

    Primo, Ana Lígia; Marques, Sónia C; Falcão, Joana; Crespo, Daniel; Pardal, Miguel A; Azeiteiro, Ulisses M

    2012-08-01

    The impact of biological, hydrodynamic and large scale climatic variables on the jellyfish community of Mondego estuary was evaluated from 2003 to 2010. Plankton samples were collected at the downstream part of the estuary. Siphonophora Muggiaea atlantica and Diphyes spp. were the main jellyfish species. Jellyfish density was generally higher in summer and since 2005 densities had increased. Summer community analysis pointed out Acartia clausi, estuarine temperature and salinity as the main driven forces for the assemblage's structure. Also, Chl a, estuarine salinity, runoff and SST were identified as the major environmental factors influencing the siphonophores summer interannual variability. Temperature influenced directly and indirectly the community and fluctuation of jellyfish blooms in the Mondego estuary. This study represents a contribution to a better knowledge of the gelatinous plankton communities in small temperate estuaries.

  15. Fish and Salinity in the San Francisco Estuary

    EPA Pesticide Factsheets

    This page provides access to a set of time-series maps for six fishes that live in the SF Estuary. Maps were produced to strengthen best available science that inform actions needed to improve protection for aquatic life.

  16. Monitoring Rehabilitation in Temperate North American Estuaries

    SciTech Connect

    Rice, Casimir A.; Hood, W Gregory; Tear, Lucinda M.; Simenstad, Charles; Williams, Gregory D.; Johnson, L. L.; Feist, B. E.; Roni, P.

    2005-02-01

    In this chapter, we propose that monitoring rehabilitation in estuarine ecosystems by necessity requires quantifying relationships between dynamic estuarine processes and sensitive indicators of ecosystem function. While we do discuss temperate systems in general, emphasis is placed on anadromous salmon habitats in the Pacific Northwest because anadromous fishes are such a major focus of rehabilitation efforts, and present some of the greater challenges in linking function of one segment of their life history to conditions in a specific habitat. We begin with a basic overview of the ecological and socioeconomic significance of, as well as anthropogenic effects on, estuaries. Next, we briefly summarize the various kinds of estuarine rehabilitation historically practiced in temperate regions, and review estuarine rehabilitation monitoring design and methods, highlighting the unique challenges involved in monitoring estuarine systems. We then close with a summary and conclusions.

  17. Columbia Bay, Alaska: an 'upside down' estuary

    USGS Publications Warehouse

    Walters, R.A.; Josberger, E.G.; Driedger, C.L.

    1988-01-01

    Circulation and water properties within Columbia Bay, Alaska, are dominated by the effects of Columbia Glacier at the head of the Bay. The basin between the glacier terminus and the terminal moraine (sill depth of about 22 m) responds as an 'upside down' estuary with the subglacial discharge of freshwater entering at the bottom of the basin. The intense vertical mixing caused by the bouyant plume of freshwater creates a homogeneous water mass that exchanges with the far-field water through either a two- or a three-layer flow. In general, the glacier acts as a large heat sink and creates a water mass which is cooler than that in fjords without tidewater glaciers. The predicted retreat of Columbia Glacier would create a 40 km long fjord that has characteristics in common with other fjords in Prince William Sound. ?? 1988.

  18. Yeast community survey in the Tagus estuary.

    PubMed

    de Almeida, João M G C F

    2005-07-01

    The yeast community in the waters of the Tagus estuary, Portugal, was followed for over a year in order to assess its dynamics. Yeast occurrence and incidence were measured and this information was related to relevant environmental data. Yeast occurrence did not seem to depend upon tides, but river discharge had a dramatic impact both on the density and diversity of the community. The occurrence of some yeasts was partially correlated with faecal pollution indicators. Yeast isolates were characterized by microsatellite primed PCR (MSP-PCR) fingerprinting and rRNA gene sequencing. The principal species found were Candida catenulata, C. intermedia, C. parapsilosis, Clavispora lusitaniae, Debaryomyces hansenii, Pichia guilliermondii, Rhodotorula mucilaginosa and Rhodosporidium diobovatum. The incidence of these species was evaluated against the environmental context of the samples and the current knowledge about the substrates from which they are usually isolated.

  19. Master File Feasibility Study.

    ERIC Educational Resources Information Center

    Broadbent, William A.

    The three purposes for which this study was conducted involved collection and summarization of otherwise unavailable data on student characteristics and aspirations, editing and summarization of reading test data collected over the past six years, and testing of the feasibility and utility of a computerized master file combining student data…

  20. Educational Feasibility Study -- 1966.

    ERIC Educational Resources Information Center

    Hubbard, Ben C., Comp.; And Others

    By virtue of a Title III Elementary and Secondary Education Act grant, the feasibility of consolidating 7 Illinois high schools was studied. Areas of consideration were geographic characteristics, high school and elementary curriculum, and cost considerations relative to high school and elementary school buildings, curriculum, transportation,…

  1. Modeling flocculation in a hypertidal estuary

    NASA Astrophysics Data System (ADS)

    Ramírez-Mendoza, Rafael; Souza, Alejandro J.; Amoudry, Laurent O.

    2014-01-01

    When fine particles are involved, cohesive properties of sediment can result in flocculation and significantly complicate sediment process studies. We combine data from field observations and state-of-the-art modeling to investigate and predict flocculation processes within a hypertidal estuary. The study site is the Welsh Channel located at the entrance of the Dee Estuary in Liverpool Bay. Field data consist of measurements from a fixed site deployment during 12-22 February 2008. Grain size, suspended sediment volume concentration, and current velocity were obtained hourly from moored instruments at 1.5 m above bed. Near-bottom water samples taken every hour from a research vessel are used to convert volume concentrations to mass concentrations for the moored measurements. We use the hydrodynamic model Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS) coupled with the turbulence model General Ocean Turbulence Model (GOTM) and a sediment module to obtain three-dimensional distributions of suspended particulate matter (SPM). Flocculation is identified by changes in grain size. Small flocs were found during flood and ebb periods—and correlate with strong currents—due to breakup, while coarse flocs were present during slack waters because of aggregation. A fractal number of 2.4 is found for the study site. Turbulent stresses and particle settling velocities are estimated and are found to be related via an exponential function. The result is a simple semiempirical formulation for the fall velocity of the particles solely depending on turbulent stresses. The formula is implemented in the full three-dimensional model to represent changes in particle size due to flocculation processes. Predictions from the model are in agreement with observations for both settling velocity and SPM. The SPM fortnight variability was reproduced by the model and the concentration peaks are almost in phase with those from field data.

  2. Continuous resistivity profiling data from the Corsica River Estuary, Maryland

    USGS Publications Warehouse

    Cross, V.A.; Bratton, J.F.; Worley, C.R.; Crusius, J.; Kroeger, K.D.

    2011-01-01

    Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine its importance in nutrient delivery to the Chesapeake Bay. The Corsica River Estuary represents a coastal lowland setting typical of much of the eastern bay. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the lower estuary in April and May 2007. Resource managers are concerned about nutrients that are entering the estuary via SGD that may be contributing to eutrophication, harmful algal blooms, and fish kills. Techniques employed in the study included continuous resistivity profiling (CRP), piezometer sampling of submarine groundwater, and collection of a time series of radon tracer activity in surface water. A CRP system measures electrical resistivity of saturated subestuarine sediments to distinguish those bearing fresh water (high resistivity) from those with saline or brackish pore water (low resistivity). This report describes the collection and processing of CRP data and summarizes the results. Based on a grid of 67.6 kilometers of CRP data, low-salinity (high-resistivity) groundwater extended approximately 50-400 meters offshore from estuary shorelines at depths of 5 to >12 meters below the sediment surface, likely beneath a confining unit. A band of low-resistivity sediment detected along the axis of the estuary indicated the presence of a filled paleochannel containing brackish groundwater. The meandering paleochannel likely incised through the confining unit during periods of lower sea level, allowing the low-salinity groundwater plumes originating from land to mix with brackish subestuarine groundwater along the channel margins and to discharge. A better understanding of the spatial variability and geological controls of submarine groundwater flow beneath the Corsica River Estuary could lead to improved models and mitigation strategies for nutrient over-enrichment in the

  3. Contamination and restoration of an estuary affected by phosphogypsum releases.

    PubMed

    Villa, M; Mosqueda, F; Hurtado, S; Mantero, J; Manjón, G; Periañez, R; Vaca, F; García-Tenorio, R

    2009-12-15

    The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides 226Ra and 210Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of 210Pb and 226Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for 226Ra and 210Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary can be performed via natural

  4. Snohomish Estuary Wetlands Study. Volume I. Summary Report

    DTIC Science & Technology

    1979-05-01

    and provides a detailed identification and evaluation of all wetlands in the Snohomish River Estuary. The study recognizes that in consideration and...Jurisdiction in the Study Area IV. THE PERMIT PROCESS 23 V. FINDINGS IN THE SNOHOMISH ESTUARY 27 A. The Importance and Identification of Wetlands 29 SB. Areas...District is described in Section IV. 3. The major findings of the study are sunimuarized in Section V. The first major finding is an identification and

  5. Biological effects of anthropogenic contaminants in the San Francisco Estuary

    USGS Publications Warehouse

    Thompson, B.; Adelsbach, T.; Brown, C.; Hunt, J.; Kuwabara, J.; Neale, J.; Ohlendorf, H.; Schwarzbach, S.; Spies, R.; Taberski, K.

    2007-01-01

    Concentrations of many anthropogenic contaminants in the San Francisco Estuary exist at levels that have been associated with biological effects elsewhere, so there is a potential for them to cause biological effects in the Estuary. The purpose of this paper is to summarize information about biological effects on the Estuary's plankton, benthos, fish, birds, and mammals, gathered since the early 1990s, focusing on key accomplishments. These studies have been conducted at all levels of biological organization (sub-cellular through communities), but have included only a small fraction of the organisms and contaminants of concern in the region. The studies summarized provide a body of evidence that some contaminants are causing biological impacts in some biological resources in the Estuary. However, no general patterns of effects were apparent in space and time, and no single contaminant was consistently related to effects among the biota considered. These conclusions reflect the difficulty in demonstrating biological effects due specifically to contamination because there is a wide range of sensitivity to contaminants among the Estuary's many organisms. Additionally, the spatial and temporal distribution of contamination in the Estuary is highly variable, and levels of contamination covary with other environmental factors, such as freshwater inflow or sediment-type. Federal and State regulatory agencies desire to develop biological criteria to protect the Estuary's biological resources. Future studies of biological effects in San Francisco Estuary should focus on the development of meaningful indicators of biological effects, and on key organism and contaminants of concern in long-term, multifaceted studies that include laboratory and field experiments to determine cause and effect to adequately inform management and regulatory decisions. ?? 2006 Elsevier Inc. All rights reserved.

  6. Nutrients, hypoxia and Mass Fishkill events in Tapi Estuary, India

    NASA Astrophysics Data System (ADS)

    Ram, Anirudh; Jaiswar, Jiyalal Ram M.; Rokade, M. A.; Bharti, S.; Vishwasrao, C.; Majithiya, D.

    2014-07-01

    From 1983 to 2011, dissolved oxygen (DO) conditions in the Tapi Estuary changed from normoxic to hypoxic due to increased and untreated discharge of sewage. Both tidal and day-night variations of DO were best explained by hydrographic factors, sewage pollution and phytoplankton dynamics in upper, middle, lower estuary and the coastal water. Hypoxia/anoxia was associated with low-flow periods due to riverine restrictions and changing in climatic condition. The upper Tapi Estuary becomes anoxic during summer irrespective of tide while the middle estuary was anoxic (<0.2 mg O2 l-1) during post and premonsoon seasons and hypoxic (<2.0 mg O2 l-1) during monsoon season. Differences in the degree of stratification, sewage discharge and flushing accounted for differences in DO. Because of high nutrient concentrations (maximum NO3--N 103.1, NO2--N 26.0, NH4+-N 104.0 and PO43--P 99.0 μmol l-1), the lower estuary remains DO deficient between 2.0 and 5.0 mg O2 l-1, most of the time. The environmental condition of Tapi Estuary has impacted the coastal water of the Arabian Sea in recent years with fish kills attributed to its hypoxic/anoxic condition. Enhanced concentrations of nutrients and organic matter from indiscriminate discharge of sewage into the Tapi Estuary and restricted flushing as a result of construction of a series of dams in the catchment area of the estuary are the primary factors that have lead to the development of hypoxia.

  7. Juvenile Salmon Usage of the Skeena River Estuary

    PubMed Central

    Carr-Harris, Charmaine; Gottesfeld, Allen S.; Moore, Jonathan W.

    2015-01-01

    Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2–8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations

  8. Juvenile salmon usage of the Skeena River estuary.

    PubMed

    Carr-Harris, Charmaine; Gottesfeld, Allen S; Moore, Jonathan W

    2015-01-01

    Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2-8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that

  9. Attenuation of rare earth elements in a boreal estuary

    NASA Astrophysics Data System (ADS)

    Åström, Mats E.; Österholm, Peter; Gustafsson, Jon Petter; Nystrand, Miriam; Peltola, Pasi; Nordmyr, Linda; Boman, Anton

    2012-11-01

    This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity < 6‰). Surface water was collected in a transect from the creek mouth to the outer estuary, and settling (particulate) material in sediment traps moored at selected locations in the estuary. Ultrafiltration, high-resolution ICP-MS and modeling were applied on the waters, and a variety of chemical reagents were used to extract metals from the settling material. Aluminium, Fe and REE transported by the acidic creek were extensively removed in the inner/central estuary where the acidic water was neutralised, whereas Mn was relatively persistent in solution and thus redistributed to particles and deposited further down the estuary. The REE removal was caused by several contemporary mechanisms: co-precipitation with oxyhydroxides (mainly Al but also Fe), complexation with flocculating humic substances and sorption to suspended particles. Down estuary the dissolved REE pool, remaining after removal, was fractionated: the <1 kDa pool became depleted in the middle REE and the colloidal (0.45 μm-1 kDa) pool depleted in the middle and heavy REE. This fractionation was controlled by the removal process, such that those REE with highest affinity for the settling particles became most depleted in the remaining dissolved pool. Modeling, based on Visual MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (<0.45 μm) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.

  10. Northern New Mexico regional airport market feasibility

    SciTech Connect

    Drake, R.H.; Williams, D.S.

    1998-06-01

    This report is about the market for airline travel in northern New Mexico. Interest in developing a northern New Mexico regional airport has periodically surfaced for a number of years. The New Mexico State Legislature passed a memorial during the 1998 Second Session calling for the conduct of a study to determine the feasibility of building a new regional airport in NNM. This report is a study of the passenger market feasibility of such an airport. In addition to commercial passenger market feasibility, there are other feasibility issues dealing with siting, environmental impact, noise, economic impact, intermodal transportation integration, region-wide transportation services, airport engineering requirements, and others. These other feasibility issues are not analyzed in any depth in this report although none were discovered to be show-stoppers as a by-product of the authors doing research on the passenger market itself. Preceding the need for a detailed study of these other issues is the determination of the basic market need for an airport with regular commercial airline service in the first place. This report is restricted to an in-depth look at the market for commercial passenger air service in NNM. 20 figs., 8 tabs.

  11. Wind Wave Behavior in Fetch and Depth Limited Estuaries

    NASA Astrophysics Data System (ADS)

    Karimpour, Arash; Chen, Qin; Twilley, Robert R.

    2017-01-01

    Wetland dominated estuaries serve as one of the most productive natural ecosystems through their ecological, economic and cultural services, such as nursery grounds for fisheries, nutrient sequestration, and ecotourism. The ongoing deterioration of wetland ecosystems in many shallow estuaries raises concerns about the contributing erosive processes and their roles in restraining coastal restoration efforts. Given the combination of wetlands and shallow bays as landscape components that determine the function of estuaries, successful restoration strategies require knowledge of wind wave behavior in fetch and depth limited water as a critical design feature. We experimentally evaluate physics of wind wave growth in fetch and depth limited estuaries. We demonstrate that wave growth rate in shallow estuaries is a function of wind fetch to water depth ratio, which helps to develop a new set of parametric wave growth equations. We find that the final stage of wave growth in shallow estuaries can be presented by a product of water depth and wave number, whereby their product approaches 1.363 as either depth or wave energy increases. Suggested wave growth equations and their asymptotic constraints establish the magnitude of wave forces acting on wetland erosion that must be included in ecosystem restoration design.

  12. [The benthic fauna of Sabancuy Estuary, Campeche, Mexico].

    PubMed

    González Solís, A; Torruco Gómez, D

    2001-03-01

    The fish and invertebrates community structure in the Sabancuy estuary was analyzed in two seasons and 14 sampling stations (13 along the estuary and one in the marine adjacent coast). No significant differences were found between seasons. The environmental frame defines two zones within the estuary, the first extends from the access highway to Sabancuy town until the Pujo mouth in the west; the second from the bridge to the estuary head in the east. The most abundant invertebrates were mollusks (51.8% of the total), in biomass the crustaceans dominated. The fish included 21 families and 33 species; the most abundant were Gerridae, Scianidae, Sparidae, Lutjanidae and Ciprinodontidae. The highest diversities of both communities correspond to the central part of the estuary. These communities include three sections with notable differences in faunal distribution: one is influenced by the exit to Terminos lagoon, the secondary in the estuary head and a third is in a transition zone defined by the proximity of the town access bridge. The ecological organization suggests a strong division caused by the bridge, both sides are scarce in habitats and nutrient resources and this is reflected in the low species counts.

  13. Sources, Ages, and Alteration of Organic Matter in Estuaries.

    PubMed

    Canuel, Elizabeth A; Hardison, Amber K

    2016-01-01

    Understanding the processes influencing the sources and fate of organic matter (OM) in estuaries is important for quantifying the contributions of carbon from land and rivers to the global carbon budget of the coastal ocean. Estuaries are sites of high OM production and processing, and understanding biogeochemical processes within these regions is key to quantifying organic carbon (Corg) budgets at the land-ocean margin. These regions provide vital ecological services, including nutrient filtration and protection from floods and storm surge, and provide habitat and nursery areas for numerous commercially important species. Human activities have modified estuarine systems over time, resulting in changes in the production, respiration, burial, and export of Corg. Corg in estuaries is derived from aquatic, terrigenous, and anthropogenic sources, with each source exhibiting a spectrum of ages and lability. The complex source and age characteristics of Corg in estuaries complicate our ability to trace OM along the river-estuary-coastal ocean continuum. This review focuses on the application of organic biomarkers and compound-specific isotope analyses to estuarine environments and on how these tools have enhanced our ability to discern natural sources of OM, trace their incorporation into food webs, and enhance understanding of the fate of Corg within estuaries and their adjacent waters.

  14. PCBs in the fish assemblage of a southern European estuary

    NASA Astrophysics Data System (ADS)

    Baptista, Joana; Pato, Pedro; Pereira, Eduarda; Duarte, Armando C.; Pardal, Miguel A.

    2013-02-01

    The Mondego estuary fish assemblage was studied for the accumulation of PCBs. Three sampling stations were visited along an estuarine salinity gradient, and, in total, 15 species were collected. Analysis of PCBs revealed no significant differences among the sampling stations, although differences were observed among the fish assemblages. Fish assemblages could be divided into three groups. The first group comprised those with higher concentration (more than 10 ng g- 1, dw), included the species Gobius niger, Sardina pilchardus, Anguilla anguilla, Pomatoschistus microps, Chelidonichthys lucerna and Liza ramada; the second group with medium concentration (5-10 ng g- 1, dw), included the species Pomatoschistus minutus, Dicentrarchus labrax, Atherina presbyter, Chelon labrosus, Diplodus vulgaris, Platichthys flesus and Cilata mustela; and a third group with low concentration (less than 5 ng g- 1, dw), included the species Solea solea and Callionymus lyra. A positive correlation was found between lipid content and PCB concentrations. To evaluate the influence of the residence time of species on the accumulation of PCBs, species were divided into two groups: species that spend more than 3 years in the estuary, and species that spend less than 3 years in the estuary. Species that spend more than 3 years in the estuary presented higher concentrations than species that spend less than 3 years in the estuary. CBs 138 and 153 had higher concentration, and tended to increase with time spent in the estuary.

  15. Wind Wave Behavior in Fetch and Depth Limited Estuaries.

    PubMed

    Karimpour, Arash; Chen, Qin; Twilley, Robert R

    2017-01-18

    Wetland dominated estuaries serve as one of the most productive natural ecosystems through their ecological, economic and cultural services, such as nursery grounds for fisheries, nutrient sequestration, and ecotourism. The ongoing deterioration of wetland ecosystems in many shallow estuaries raises concerns about the contributing erosive processes and their roles in restraining coastal restoration efforts. Given the combination of wetlands and shallow bays as landscape components that determine the function of estuaries, successful restoration strategies require knowledge of wind wave behavior in fetch and depth limited water as a critical design feature. We experimentally evaluate physics of wind wave growth in fetch and depth limited estuaries. We demonstrate that wave growth rate in shallow estuaries is a function of wind fetch to water depth ratio, which helps to develop a new set of parametric wave growth equations. We find that the final stage of wave growth in shallow estuaries can be presented by a product of water depth and wave number, whereby their product approaches 1.363 as either depth or wave energy increases. Suggested wave growth equations and their asymptotic constraints establish the magnitude of wave forces acting on wetland erosion that must be included in ecosystem restoration design.

  16. Conservation of Thane Creek and Ulhas River Estuary, India.

    PubMed

    Nikam, Vinay S; Kumar, Arun; Lalla, Kamal; Gupta, Kapil

    2009-07-01

    There has been a steady decrease in the area occupied by wetlands in creeks and estuaries adjacent urban areas due to unprecedented urban growth in coastal cities, for example, Thane Creek and Ulhas River Estuary near Mumbai, India. Urban cities serve as centres of employment and attract a large number of migrants from other places. In case of coastal cities, due to inadequate infrastructure, wastewater and solid waste are disposed of into wetlands and estuary. Discharge of sediments and solid waste into the creeks from drains and construction activities has resulted in decreased flow depth in the coastal waters of Thane Creek and Ulhas River Estuary. Various researchers have studied individual elements of Thane Creek and Ulhas River Estuary at micro level. However, a holistic approach for restoration and conservation of the creek and estuary is required. This paper presents the details of an integrated approach incorporating different conservation measures such as sewerage and sewage treatment, urban drainage management, solid waste management, mangrove plantation and dredging.

  17. Sources, Ages, and Alteration of Organic Matter in Estuaries

    NASA Astrophysics Data System (ADS)

    Canuel, Elizabeth A.; Hardison, Amber K.

    2016-01-01

    Understanding the processes influencing the sources and fate of organic matter (OM) in estuaries is important for quantifying the contributions of carbon from land and rivers to the global carbon budget of the coastal ocean. Estuaries are sites of high OM production and processing, and understanding biogeochemical processes within these regions is key to quantifying organic carbon (Corg) budgets at the land-ocean margin. These regions provide vital ecological services, including nutrient filtration and protection from floods and storm surge, and provide habitat and nursery areas for numerous commercially important species. Human activities have modified estuarine systems over time, resulting in changes in the production, respiration, burial, and export of Corg. Corg in estuaries is derived from aquatic, terrigenous, and anthropogenic sources, with each source exhibiting a spectrum of ages and lability. The complex source and age characteristics of Corg in estuaries complicate our ability to trace OM along the river-estuary-coastal ocean continuum. This review focuses on the application of organic biomarkers and compound-specific isotope analyses to estuarine environments and on how these tools have enhanced our ability to discern natural sources of OM, trace their incorporation into food webs, and enhance understanding of the fate of Corg within estuaries and their adjacent waters.

  18. Wind Wave Behavior in Fetch and Depth Limited Estuaries

    PubMed Central

    Karimpour, Arash; Chen, Qin; Twilley, Robert R.

    2017-01-01

    Wetland dominated estuaries serve as one of the most productive natural ecosystems through their ecological, economic and cultural services, such as nursery grounds for fisheries, nutrient sequestration, and ecotourism. The ongoing deterioration of wetland ecosystems in many shallow estuaries raises concerns about the contributing erosive processes and their roles in restraining coastal restoration efforts. Given the combination of wetlands and shallow bays as landscape components that determine the function of estuaries, successful restoration strategies require knowledge of wind wave behavior in fetch and depth limited water as a critical design feature. We experimentally evaluate physics of wind wave growth in fetch and depth limited estuaries. We demonstrate that wave growth rate in shallow estuaries is a function of wind fetch to water depth ratio, which helps to develop a new set of parametric wave growth equations. We find that the final stage of wave growth in shallow estuaries can be presented by a product of water depth and wave number, whereby their product approaches 1.363 as either depth or wave energy increases. Suggested wave growth equations and their asymptotic constraints establish the magnitude of wave forces acting on wetland erosion that must be included in ecosystem restoration design. PMID:28098236

  19. DISK PUMP FEASIBILITY INVESTIGATION,

    DTIC Science & Technology

    The disk pump was investigated at the Air Force Rocket Propulsion Laboratory (AFRPL) to determine the feasibility of using a novel viscous pumping... pump primarily for application as an inducer. The disk pump differs drastically from conventional pumps because of the following major factors: (1) The...The pump inlet relative velocity is equal only to the through flow velocity between the disks. Therefore, there is good indication that the disk pump will

  20. A hydrologic and geomorphic model of estuary breaching and closure

    NASA Astrophysics Data System (ADS)

    Rich, Andrew; Keller, Edward A.

    2013-06-01

    To better understand how the hydrology of bar-built estuaries affects breaching and closing patterns, a model is developed that incorporates an estuary hydrologic budget with a geomorphic model of the inlet system. Erosion of the inlet is caused by inlet flow, whereas the only morphologic effect of waves is the deposition of sand into the inlet. When calibrated, the model is able to reproduce the initial seasonal breaching, seasonal closure, intermittent closures and breaches, and the low-streamflow (closed state) estuary hydrology of the Carmel Lagoon, located in Central California. Model performance was tested against three separate years of water-level observations. When open during these years, the inlet was visually observed to drain directly across the beach berm, in accordance with model assumptions. The calibrated model predicts the observed 48-h estuary stage amplitude with root mean square errors of 0.45 m, 0.39 m and 0.42 m for the three separate years. For the calibrated model, the probability that the estuary inlet is closed decreases exponentially with increasing inflow (streamflow plus wave overtopping), decreasing 10-fold in probability as mean daily inflow increases from 0.2 to 1.0 m3/s. Seasonal patterns of inlet state reflect the seasonal pattern of streamflow, though wave overtopping may become the main hydrologic flux during low streamflow conditions, infrequently causing short-lived breaches. In a series of sensitivity analyses it is seen that the status of the inlet and storage of water are sensitive to factors that control the storage, transmission, and inflow of water. By varying individual components of the berm system and estuary storage, the amount of the time the estuary is open may increase by 57%, or decrease by 44%, compared to the amount of time the estuary is open during calibrated model conditions for the 18.2-year model period. The individual components tested are: berm height, width, length, and hydraulic conductivity; estuary

  1. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia).

    PubMed

    Musenze, Ronald S; Werner, Ursula; Grinham, Alistair; Udy, James; Yuan, Zhiguo

    2014-02-15

    Methane (CH4) and nitrous oxide (N2O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water-air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH4 and N2O all-year-round. Dissolved N2O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH4 concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH4 and N2O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N2O saturation significantly increased with NOx concentrations (r(2)=0.55). The estimated water-air fluxes varied between 0.1 and 3.4 mg N2O m(-2)d(-1) and 0.3 to 27.9 mg CH4 m(-2)d(-1). Total emissions (CO2-e) were N2O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions.

  2. Columbia River Estuary Ecosystem Classification Hydrogeomorphic Reach

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  3. Columbia River Estuary Ecosystem Classification Geomorphic Catena

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  4. Columbia River Estuary Ecosystem Classification Ecosystem Complex

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith Marcoe

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  5. Biogeography of dinoflagellate cysts in northwest Atlantic estuaries.

    PubMed

    Price, Andrea M; Pospelova, Vera; Coffin, Michael R S; Latimer, James S; Chmura, Gail L

    2016-08-01

    Few biogeographic studies of dinoflagellate cysts include the near-shore estuarine environment. We determine the effect of estuary type, biogeography, and water quality on the spatial distribution of organic-walled dinoflagellate cysts from the Northeast USA (Maine to Delaware) and Canada (Prince Edward Island). A total of 69 surface sediment samples were collected from 27 estuaries, from sites with surface salinities >20. Dinoflagellate cysts were examined microscopically and compared to environmental parameters using multivariate ordination techniques. The spatial distribution of cyst taxa reflects biogeographic provinces established by other marine organisms, with Cape Cod separating the northern Acadian Province from the southern Virginian Province. Species such as Lingulodinium machaerophorum and Polysphaeridinium zoharyi were found almost exclusively in the Virginian Province, while others such as Dubridinium spp. and Islandinium? cezare were more abundant in the Acadian Province. Tidal range, sea surface temperature (SST), and sea surface salinity (SSS) are statistically significant parameters influencing cyst assemblages. Samples from the same type of estuary cluster together in canonical correspondence analysis when the estuaries are within the same biogeographic province. The large geographic extent of this study, encompassing four main estuary types (riverine, lagoon, coastal embayment, and fjord), allowed us to determine that the type of estuary has an important influence on cyst assemblages. Due to greater seasonal variations in SSTs and SSSs in estuaries compared to the open ocean, cyst assemblages show distinct latitudinal trends. The estuarine context is important for understanding present-day species distribution, the factors controlling them, and to better predict how they may change in the future.

  6. Recovery simulations of grossly polluted sediments in the Bilbao Estuary.

    PubMed

    Antonio González Oreja, José; Ignacio Saiz Salinas, José

    2003-01-01

    The Bilbao Estuary is one of the most contaminated estuaries on the north coast of Spain, and vast efforts have been made to abate pollution there. In fact, the local water authority has forecast a biological recovery of the native fauna after a substantial increase in dissolved oxygen to normoxic levels. In order to assess this prediction by evaluating the extent of natural regeneration of these polluted sediments, two long-term bioassays (t=90 d) were performed. In both of them, lethal (differences in survival) and sublethal (differences in length and weight growth) effects were measured by using juvenile individuals of the autochthonous clam, Scrobicularia plana (Da Costa, 1778). The sediments tested differed in pollution levels, as measured by a set of indicators including PAHs, PCBs, heavy metals, volatile organic matter and coprostanol. All sediments were finally exposed to normoxic conditions in situ in the Bilbao Estuary (DO approximately 6.3 mg l(-1)). In the first experiment, concerning moderately polluted sediments from the Bilbao Estuary and reference sediments from the "pristine" Plentzia Estuary, no significant differences (P>0.05) were found regarding animal survival (approximately 94.5%) or growth in length or weight between the sediments tested. In the second experiment, also involving grossly polluted sediments (GPS) from the Bilbao Estuary, survival (24.5%) was statistically lower (P<0.05) than in the other sediments (approximately 93%). No significant differences were found in growth (length, weight) between animals exposed to moderately polluted or reference sediments. We interpret this dramatic difference in survival as the lethal effect on the animals tested of the GPS of the Bilbao Estuary, indicating a situation where biological recovery is not possible due to the adverse consequences of contaminants sorbed into sediments. The extensive use of this inexpensive bioassay could help to distinguish sediments in which homeostatic recovery is

  7. Urban microbial ecology of a freshwater estuary of Lake Michigan

    PubMed Central

    Fisher, Jenny C.; Newton, Ryan J.; Dila, Deborah K.

    2015-01-01

    Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an “urban microbial signature,” and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas, and Pseudomonas, which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is likely to occur with

  8. The status of fish conservation in South African estuaries.

    PubMed

    Whitfield, A K; Cowley, P D

    2010-06-01

    Estuary-dependent fish species are defined as those taxa whose populations would be adversely affected by the loss of estuarine habitats. Of the 155 species regularly recorded in South African estuaries, only 32 (21%) are completely dependent on these systems, but this figure increases to 103 species (66%) if partially dependent taxa are included in the analysis. The conservation of fishes in estuaries on the subcontinent is threatened by a number of factors, including habitat degradation, disruption of essential ecological processes, hydrological manipulations, environmental pollution, overexploitation due to fishing activities and, more recently, climate change and the effects of introduced aquatic animals. Although major threats to fishes are usually linked to environmental degradation, there is increasing evidence that the stocks of certain fish species are overexploited or collapsed. Fish conservation and fisheries management does not depend on the implementation of a single action, but rather the co-ordination of a detailed plan, often in a multidisciplinary context. Some examples of innovative means of contributing to estuarine fish conservation in a South African context include the determination and implementation of the ecological freshwater requirements for estuaries, the zoning of estuaries for different uses and the recognition that the maintenance of ecological processes are vital to aquatic ecosystem health. Apart from the designation of protected areas, the main direct means of conserving fish species and stocks include habitat conservation, controls over fishing methods, effort, efficiency and seasonality, pollution control and the prevention of artificial manipulation of estuary mouths. Since becoming a democracy in 1994, environmental legislation, policy and institutional arrangements in South Africa have undergone some major changes, which, if fully implemented, will be very positive for fish conservation in estuaries on the subcontinent.

  9. Urban microbial ecology of a freshwater estuary of Lake Michigan.

    PubMed

    Fisher, Jenny C; Newton, Ryan J; Dila, Deborah K; McLellan, Sandra L

    Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an "urban microbial signature," and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas, and Pseudomonas, which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is likely to occur with potential

  10. Modelling of cohesive sediment dynamics in tidal estuarine systems: Case study of Tagus estuary, Portugal

    NASA Astrophysics Data System (ADS)

    Franz, G.; Pinto, L.; Ascione, I.; Mateus, M.; Fernandes, R.; Leitão, P.; Neves, R.

    2014-12-01

    Cohesive sediment dynamics in estuarine systems is a major issue in water quality and engineering problems. Numerical models can help to assess the complex dynamics of cohesive sediments, integrating the information collected in monitoring studies. Following a numerical approach we investigated the main factors that influence the cohesive sediment dynamics in an estuarine system composed of large mudflats (Tagus estuary, Portugal). After a spin up period of the bottom layer and considering the combined effect of waves and currents on the bottom shear stress, the dynamics of cohesive sediment during the fortnightly and daily erosion-sedimentation cycle was properly reproduced by the model. The results of cohesive suspended sediments were validated with data from sixteen monitoring stations located along the estuary and turbidity data measured by two multiparametric probes. The hydrodynamics were previously validated by harmonic analysis and with ADCP data. Although tidal currents are the major cause of cohesive sediment erosion, the results suggest that wind waves also play an important role. The simulated sediment mass involved in the fortnightly tidal cycle was in the same order of magnitude of the annual load from the rivers, as observed in previous studies based on field data.

  11. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2009

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Borde, Amy B.; Bryson, Amanda J.; Cameron, April; Coleman, Andre M.; Corbett, C.; Dawley, Earl M.; Ebberts, Blaine D.; Kauffman, Ronald; Roegner, G. Curtis; Russell, Micah T.; Silva, April; Skalski, John R.; Thom, Ronald M.; Vavrinec, John; Woodruff, Dana L.; Zimmerman, Shon A.

    2010-10-26

    This is the sixth annual report of a seven-year project (2004 through 2010) to evaluate the cumulative effects of habitat restoration actions in the lower Columbia River and estuary (LCRE). The project, called the Cumulative Effects Study, is being conducted for the U.S. Army Corps of Engineers Portland District (USACE) by the Marine Sciences Laboratory of the Pacific Northwest National Laboratory (PNNL), the Pt. Adams Biological Field Station of the National Marine Fisheries Service (NMFS), the Columbia River Estuary Study Taskforce (CREST), and the University of Washington. The goal of the Cumulative Effects Study is to develop a methodology to evaluate the cumulative effects of multiple habitat restoration projects intended to benefit ecosystems supporting juvenile salmonids in the 235-km-long LCRE. Literature review in 2004 revealed no existing methods for such an evaluation and suggested that cumulative effects could be additive or synergistic. From 2005 through 2009, annual field research involved intensive, comparative studies paired by habitat type (tidal swamp versus marsh), trajectory (restoration versus reference site), and restoration action (tidegate replacement vs. culvert replacement vs. dike breach).

  12. 76 FR 14924 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... Specified Activities; Russian River Estuary Management Activities AGENCY: National Marine Fisheries Service... incidental to Russian River estuary management activities. Pursuant to the Marine Mammal Protection Act (MMPA... Channel Adaptive Management Plan. NMFS' Environmental Assessment (2010) and associated Finding of...

  13. CLASSIFYING OREGON ESTUARIES BY HABITAT: ANALYSIS OF EXISTING DATA AND A PROPOSAL FOR A PILOT STUDY

    EPA Science Inventory

    Because many estuarine resources are linked to benthic habitats, classification of estuaries by habitat types may prove a relevant approach for grouping estuaries with similar ecological values and vulnerability to landscape alterations. As a first step, we evaluated whether pub...

  14. Feasibility studies of aquifer thermal energy storage

    SciTech Connect

    Hall, S. H.

    1993-01-01

    Determining the feasibility of using aquifer thermal energy storage (ATES) for a particular heating or cooling application is an interdisciplinary effort, requiring (at a minimum) expertise in engineering and hydrology. The feasibility study should proceed in two distinct stages. The first stage, which is limited in scope and detail, is intended to show if an ATES system is technically and economically suited to the application. Focus of this preliminary investigation is on revealing the existence of factors that might weigh heavily against the use of ATES methods, and, in the absence of such factors, on choosing a suitable scale for the ATES plant and well field. The results of the preliminary investigation are used to determine if more detailed investigation--including field studies--are justified, and to facilitate comparing the advantages of ATES to those of other means of providing heating or cooling. The second stage of the feasibility study focuses on detailed aquifer characterization, refinement of engineering design and cost estimates, and economic and environmental risk analysis. The results of this investigation, if favorable, will be used to justify the expense of constructing the ATES system.

  15. Dynamics of intertidal flats in the Loire estuary

    NASA Astrophysics Data System (ADS)

    Kervella, Stephane; Sottolichio, Aldo; Bertier, Christine

    2014-05-01

    Tidal flats form at the edges of many tidal estuaries, and are found in broad climatic regions. Their evolution plays a fundamental role in maintaining the morphodynamic equilibrium of an estuary. The Loire estuary is one of the largest macrotidal systems of the french atlantic coast. Since 200 years, its geometry has been drastically modified through channeling, deepening, embanking, infilling of secondary channels, etc. These works altered many intertidal areas. In the recent years, efforts for the rectification of the morphology have been made in order to restore the ecology of the estuary. In this context, it is crucial to better understand the dynamics of intertidal flats, still poorly understood in this estuary. The aim of this work is to analyse a series of original observations conducted for the first time in two intertidal flats of the central Lore estuary between 2008 and 2010. The tidal flats are situated in the northern bank, at 12 and 17 km upstream from the mouth respectively. Six Altus altimeters were deployed at two cross shore transects, measuring continuously and at a high-frequency bed altimetry and water level, providing information on tide and waves. At the semi-diurnal tidal scale, the surficial sediment of intertidal flats is permanently mobilized. Altimetry variations are low, and their amplitude varies as a function of tides and river flow. At the scale of several months, the sedimentation is controlled by the position of the turbidity maximum (and therefore by the river flow) and also by the tidal amplitude. During low river flow periods, altimetry variations are only due to tidal cycles. During decaying tides, suspended sediment settle mainly on the lower part of the tidal flats, forming fluid mud layers of several cm thick, which can consolidate rapidly; under rising tides, the increasing of tidal currents promotes erosion. During periods of high river flow, the turbidity maximum shifts to the lower estuary. The higher suspended sediment

  16. Impact of human activities on subaqueous topographic change in Lingding Bay of the Pearl River estuary, China, during 1955–2013

    PubMed Central

    Wu, Z. Y.; Saito, Yoshiki; Zhao, D. N.; Zhou, J. Q.; Cao, Z. Y.; Li, S. J.; Shang, J. H.; Liang, Y. Y.

    2016-01-01

    Estuaries have been sites of intensive human activities during the past century. Tracing the evolution of subaqueous topography in estuaries on a decadal timescale enables us to understand the effects of human activities on estuaries. Bathymetric data from 1955 to 2010 show that land reclamation decreased the subaqueous area of Lingding Bay, in the Pearl River estuary, by ~170 km2 and decreased its water volume by 615 × 106 m3, representing a net decrease of 11.2 × 106 m3 per year and indicating the deposition of approximately 14.5 Mt/yr of sediment in Lingding Bay during that period. Whereas Lingding Bay was mainly governed by natural processes with slight net deposition before 1980, subsequent dredging and large port engineering projects changed the subaqueous topography of the bay by shallowing its shoals and deepening its troughs. Between 2012 and 2013, continuous dredging and a surge of sand excavation resulted in local changes in water depth of ± 5 m/yr, far exceeding the magnitude of natural topographic evolution in Lingding Bay. Reclamation, dredging, and navigation-channel projects removed 8.4 Mt/yr of sediment from Lingding Bay, representing 29% of the sediment input to the bay, and these activities have increased recently. PMID:27886227

  17. Impact of human activities on subaqueous topographic change in Lingding Bay of the Pearl River estuary, China, during 1955-2013.

    PubMed

    Wu, Z Y; Saito, Yoshiki; Zhao, D N; Zhou, J Q; Cao, Z Y; Li, S J; Shang, J H; Liang, Y Y

    2016-11-25

    Estuaries have been sites of intensive human activities during the past century. Tracing the evolution of subaqueous topography in estuaries on a decadal timescale enables us to understand the effects of human activities on estuaries. Bathymetric data from 1955 to 2010 show that land reclamation decreased the subaqueous area of Lingding Bay, in the Pearl River estuary, by ~170 km(2) and decreased its water volume by 615 × 10(6) m(3), representing a net decrease of 11.2 × 10(6 )m(3) per year and indicating the deposition of approximately 14.5 Mt/yr of sediment in Lingding Bay during that period. Whereas Lingding Bay was mainly governed by natural processes with slight net deposition before 1980, subsequent dredging and large port engineering projects changed the subaqueous topography of the bay by shallowing its shoals and deepening its troughs. Between 2012 and 2013, continuous dredging and a surge of sand excavation resulted in local changes in water depth of ± 5 m/yr, far exceeding the magnitude of natural topographic evolution in Lingding Bay. Reclamation, dredging, and navigation-channel projects removed 8.4 Mt/yr of sediment from Lingding Bay, representing 29% of the sediment input to the bay, and these activities have increased recently.

  18. Impact of human activities on subaqueous topographic change in Lingding Bay of the Pearl River estuary, China, during 1955–2013

    NASA Astrophysics Data System (ADS)

    Wu, Z. Y.; Saito, Yoshiki; Zhao, D. N.; Zhou, J. Q.; Cao, Z. Y.; Li, S. J.; Shang, J. H.; Liang, Y. Y.

    2016-11-01

    Estuaries have been sites of intensive human activities during the past century. Tracing the evolution of subaqueous topography in estuaries on a decadal timescale enables us to understand the effects of human activities on estuaries. Bathymetric data from 1955 to 2010 show that land reclamation decreased the subaqueous area of Lingding Bay, in the Pearl River estuary, by ~170 km2 and decreased its water volume by 615 × 106 m3, representing a net decrease of 11.2 × 106 m3 per year and indicating the deposition of approximately 14.5 Mt/yr of sediment in Lingding Bay during that period. Whereas Lingding Bay was mainly governed by natural processes with slight net deposition before 1980, subsequent dredging and large port engineering projects changed the subaqueous topography of the bay by shallowing its shoals and deepening its troughs. Between 2012 and 2013, continuous dredging and a surge of sand excavation resulted in local changes in water depth of ± 5 m/yr, far exceeding the magnitude of natural topographic evolution in Lingding Bay. Reclamation, dredging, and navigation-channel projects removed 8.4 Mt/yr of sediment from Lingding Bay, representing 29% of the sediment input to the bay, and these activities have increased recently.

  19. Radiation Augmented Propulsion Feasibility.

    DTIC Science & Technology

    1985-12-01

    FE 1~ 1986 December 1985 Authors: Rockwell International S . C. Hurlock Rocketdyne Division V. Quan 6633 Canoga Ave ()J. Blauer Canoga Park, CA 91304 00...Organization Report Number( s ) RI /RD85-257 AFRPL-TR-85-068 Gam NAME OF PERFORMING ORGANIZATION b. OF FICE SY MBO L 7. NAME OF MONITORING ORGANIZATION...EW - PropulsionFeasibilityStudy_(U) ______ 12. PERSONAL AUTHOR( S ) Hurlock, S . C.; Quan, V.; Blauer, J.; Hall, J. R.; Wagner, R. I.; Wilson, R. 0. 113

  20. Potential intertidal habitat restoration sites in the Duwamish River estuary

    SciTech Connect

    Tanner, C.D.

    1991-12-01

    Restoration of wetland habitats in highly urbanized areas is generally constrained by scarcity of opportunity, adverse impacts of surrounding land use, and cost. Although areal wetland losses approach 98% in Seattle's Duwamish River estuary, the system continues to support important salmonid runs, as well as a variety of bird and mammal species. Estuarine-dependent organisms are likely limited by quality and quantity of intertidal habitat in the system. Because the long-range, estuary-wide benefit of site-specific mitigation and restoration projects is limited, it is imperative to develop estuary-wide restoration plans. Towards this end, an inventory and analysis of potential intertidal habitat restoration sites has been completed for the Duwamish River estuary. Twenty-four sites, ranging in size from 0.8 to 25 acres were identified and comparative functional potential assessed. The majority of these sites (18) occur in the upper estuary. Two sites are located in Elliott Bay, and four are located near the historic mouth of the river in the vicinity of Harbor Island. Spatial data have been developed in geographic information system (GIS) format. Other site-specific data relative to habitat restoration has also been assembled.

  1. Antibiotic Resistance of Escherichia coli Serotypes from Cochin Estuary

    PubMed Central

    Sukumaran, Divya P.; Durairaj, Srinivasan; Abdulla, Mohamed Hatha

    2012-01-01

    This study aimed at detecting the prevalence of antibiotic-resistant serotypes of Escherichia coli in Cochin estuary, India. E. coli strains were isolated during the period January 2010–December 2011 from five different stations set at Cochin estuary. Water samples from five different stations in Cochin estuary were collected on a monthly basis for a period of two years. Isolates were serotyped, antibiogram-phenotyped for twelve antimicrobial agents, and genotyped by polymerase chain reaction for uid gene that codes for β-D-glucuronidase. These E. coli strains from Cochin estuary were tested against twelve antibiotics to determine the prevalence of multiple antibiotic resistance among them. The results revealed that more than 53.33% of the isolates were multiple antibiotic resistant. Thirteen isolates showed resistance to sulphonamides and two of them contained the sul 1 gene. Class 1 integrons were detected in two E. coli strains which were resistant to more than seven antibiotics. In the present study, O serotyping, antibiotic sensitivity, and polymerase chain reaction were employed with the purpose of establishing the present distribution of multiple antibiotic-resistant serotypes, associated with E. coli isolated from different parts of Cochin estuary. PMID:23008708

  2. Metals in sediments and benthic organisms in the Mersey estuary

    NASA Astrophysics Data System (ADS)

    Langston, W. J.

    1986-08-01

    Concentrations of twelve metals were determined in sediments, seaweed ( Fucus vesiculosus), winkles ( Littorina littorea), polychaetes ( Nereis diversicolor), suspension feeding bivalves ( Mytilus edulis, Cerastoderma edule) and deposit feeding bivalves ( Macoma balthica, Scrobicularia plana) collected from the Mersey estuary between April 1980 and June 1984. Sediments and organisms in the Mersey are moderately contaminated with most of the metals measured, but mercury concentrations are consistently higher than in other United Kingdom estuaries. Comparisons with other sites in the North West of England indicate that mercury residues in organisms, though primarily dependent on sediment concentrations, are also influenced by complexation with particulate organic matter which reduces the availability of mercury. The biological availability of arsenic in Mersey sediments is similarly influenced by complexation with iron oxyhydroxides. Nereis diversicolor and Macoma balthica are the most suitable indicator species in terms of abundance and widespread distribution along the estuary, and, for the majority of metals, tissue concentrations increase upstream, reflecting corresponding gradients in sediment contamination. However mid-estuarine peaks for tin, chromium copper and nickel in Nereis indicate more localised inputs to the estuary. Correlations between lead in sediments and organisms are poor; it is suggested that hydrophilic alkyl lead compounds may be the predominant biologically available forms. Progressive reductions in mercury contamination in sediments and mercury and lead in organisms have occurred in recent years, which coincide with efforts to reduce inputs of these metals to teh Mersey estuary.

  3. The behavior of dissolved inorganic selenium in the Changjiang Estuary

    NASA Astrophysics Data System (ADS)

    Chang, Yan; Zhang, Jing; Qu, Jianguo; Zhang, Guosen; Zhang, Anyu; Zhang, Ruifeng

    2016-02-01

    To investigate the behavior of inorganic selenium species in the Changjiang Estuary, samples were taken during summer (July 2011) and winter (March 2012). Dissolved inorganic selenium (DISe) concentrations averaged 1.79 nmol/L in summer and 1.24 nmol/L in winter; the average selenite [Se(IV)] to selenate [Se(VI)] ratio [Se(IV)/Se(VI)] was 0.42 in summer and 0.61 in winter. The data show that Se(IV) and Se(VI) concentrations in the estuary behaved strictly conservatively during winter but non-conservatively during summer due to adsorption by suspended particulate matter (SPM) and assimilation by phytoplankton. In addition, the Se concentration distributions in the Changjiang Estuary were controlled by three water masses, each with a specific Se(IV)/Se(VI) ratio "signature": the Changjiang Water input, the Taiwan Warm Current, and the Yellow Sea Coastal Current. The Se(IV) concentrations were related to the nitrate, silicate, and phosphate concentrations in the estuary. The DISe and Se(IV) concentrations were comparable to those found in other coastal regions and estuaries, which were considered to be natural levels.

  4. Water Injection Feasibility for Boeing 747 Aircraft

    NASA Technical Reports Server (NTRS)

    Daggett, David L.

    2005-01-01

    Can water injection be offered at a reasonable cost to large airplane operators to reduce takeoff NO( sub x) emissions? This study suggests it may be possible. This report is a contract deliverable to NASA Glenn Research Center from the prime contractor, The Boeing Commercial Airplane Company of Seattle, WA. This study was supported by a separate contract to the Pratt & Whitney Engine Company of Hartford, CT (contract number NNC04QB58P). Aviation continues to grow and with it, environmental pressures are increasing for airports that service commercial airplanes. The feasibility and performance of an emissions-reducing technology, water injection, was studied for a large commercial airplane (e.g., Boeing 747 with PW4062 engine). The primary use of the water-injection system would be to lower NOx emissions while an important secondary benefit might be to improve engine turbine life. A tradeoff exists between engine fuel efficiency and NOx emissions. As engines improve fuel efficiency, by increasing the overall pressure ratio of the engine s compressor, the resulting increased gas temperature usually results in higher NOx emissions. Low-NO(sub x) combustors have been developed for new airplanes to control the increases in NO(sub x) emissions associated with higher efficiency, higher pressure ratio engines. However, achieving a significant reduction of NO(sub x) emissions at airports has been challenging. Using water injection during takeoff has the potential to cut engine NO(sub x) emissions some 80 percent. This may eliminate operating limitations for airplanes flying into airports with emission constraints. This study suggests an important finding of being able to offer large commercial airplane owners an emission-reduction technology that may also save on operating costs.

  5. Fusion Engineering Device design description

    SciTech Connect

    Flanagan, C.A.; Steiner, D.; Smith, G.E.

    1981-12-01

    The US Magnetic Fusion Engineering Act of 1980 calls for the operation of a Fusion Engineering Device (FED) by 1990. It is the intent of the Act that the FED, in combination with other testing facilities, will establish the engineering feasibility of magnetic fusion energy. During 1981, the Fusion Engineering Design Center (FEDC), under the guidance of a Technical Management Board (TMB), developed a baseline design for the FED. This design is summarized herein.

  6. Fusion engineering device design description

    SciTech Connect

    Flanagan, C.A.; Steiner, D.; Smith, G.E.

    1981-12-01

    The US Magnetic Fusion Engineering Act of 1980 calls for the operation of a Fusion Engineering Device (FED) by 1990. It is the intent of the Act that the FED, in combination with other testing facilities, will establish the engineering feasibility of magnetic fusion energy. During 1981, the Fusion Engineering Design Center (FEDC), under the guidance of a Technical Management Board (TMB), developed a baseline design for the FED. This design is summarized herein.

  7. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY09 Annual Report

    SciTech Connect

    Johnson, Gary E.

    2009-10-22

    This document is the annual report for fiscal year 2009 (FY09) for the project called Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort developed by the Action Agencies (Bonneville Power Administration [BPA], U.S. Army Corps of Engineers [Corps or USACE], U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS).

  8. Tripropellant Engine Study

    NASA Technical Reports Server (NTRS)

    Wheeler, D. B.

    1977-01-01

    The feasibility of modifying the space shuttle main engine (SSME) for dual mode operation was investigated. Various high power cycle engine configurations derived from the SSME were configurations that will allow sequential burning of LOX/hydrocarbon and LOX/hydrogen were studied in order to identify concepts that make maximum use of SSME hardware and best satisfy the dual mode booster engine system application. Engine cycles were formulated for LOX/RP-1, LOX/CH4, and LOX/C3H8 propellants. Flow rates and operating cycles were established and the adaptability of the major components of the SSME was evaluated.

  9. A Simple Model of Nitrogen Concentration, Throughput, and Denitrification in Estuaries

    EPA Science Inventory

    The Estuary Nitrogen Model (ENM) is a mass balance model that includes calculation of nitrogen losses within bays and estuaries using system flushing time. The model has been used to demonstrate the dependence of throughput and denitrification of nitrogen in bays and estuaries on...

  10. An historical perspective on eutrophication in the Pensacola Bay Estuary, FL, USA

    EPA Science Inventory

    In this chapter, we provide a brief description of the Pensacola Bay estuary, examining the available historical data for evidence of trends in eutrophication within the estuary. Common to many industrialized estuaries, Pensacola Bay has been subjected to unregulated point source...

  11. A comparison of CO2 dynamics and air-water fluxes in a river-dominated estuary and a mangrove-dominated marine estuary

    NASA Astrophysics Data System (ADS)

    Akhand, Anirban; Chanda, Abhra; Manna, Sudip; Das, Sourav; Hazra, Sugata; Roy, Rajdeep; Choudhury, S. B.; Rao, K. H.; Dadhwal, V. K.; Chakraborty, Kunal; Mostofa, K. M. G.; Tokoro, T.; Kuwae, Tomohiro; Wanninkhof, Rik

    2016-11-01

    The fugacity of CO2 (fCO2 (water)) and air-water CO2 flux were compared between a river-dominated anthropogenically disturbed open estuary, the Hugli, and a comparatively pristine mangrove-dominated semiclosed marine estuary, the Matla, on the east coast of India. Annual mean salinity of the Hugli Estuary (≈7.1) was much less compared to the Matla Estuary (≈20.0). All the stations of the Hugli Estuary were highly supersaturated with CO2 (annual mean 2200 µatm), whereas the Matla was marginally oversaturated (annual mean 530 µatm). During the postmonsoon season, the outer station of the Matla Estuary was under saturated with respect to CO2 and acted as a sink. The annual mean CO2 emission from the Hugli Estuary (32.4 mol C m-2 yr-1) was 14 times higher than the Matla Estuary (2.3 mol C m-2 yr-1). CO2 efflux rate from the Hugli Estuary has increased drastically in the last decade, which is attributed to increased runoff from the river-dominated estuary.

  12. A MEDLINE feasibility study.

    PubMed

    McGee, J L

    1980-07-01

    A MEDLINE feasibility study was conducted with the Northeastern Consortium for Health Information (NECHI) and sponsored by the New England Regional Medical Library Service. It is based on the theory that most potential users and supporters of MEDLINE within hospitals are unaware of its usefulness and applications, and that there exists a need for expanding MEDLINE services to more hospital libraries. The purpose of the study was to provide NECHI with an evaluation of MEDLINE as a feasible service by ascertaining the need and by evaluating the usefulness, satisfaction, and costs of the system. The study demonstrated sufficient use of MEDLINE to justify implementation within NECHI and it provided useful data to determine the future of MEDLINE in each institution. It documented that utilization improved rapidly with publicity and the presence of the system within an institution, that MEDLINE can be an effective and economical complement to the traditional reference services used to support information needs in hospitals, and that more hospital libraries should be able to implement MEDLINE to their advantage once potential users and supporters have been exposed to the system.

  13. Numerical aerodynamic simulation facility feasibility study

    NASA Technical Reports Server (NTRS)

    1979-01-01

    There were three major issues examined in the feasibility study. First, the ability of the proposed system architecture to support the anticipated workload was evaluated. Second, the throughput of the computational engine (the flow model processor) was studied using real application programs. Third, the availability reliability, and maintainability of the system were modeled. The evaluations were based on the baseline systems. The results show that the implementation of the Numerical Aerodynamic Simulation Facility, in the form considered, would indeed be a feasible project with an acceptable level of risk. The technology required (both hardware and software) either already exists or, in the case of a few parts, is expected to be announced this year. Facets of the work described include the hardware configuration, software, user language, and fault tolerance.

  14. Impact of the Clean Water Act on the levels of toxic metals in urban estuaries: The Hudson River estuary revisited

    SciTech Connect

    Sanudo-Wilhelmy, S.A.; Gill, G.A.

    1999-10-15

    To establish the impact of the Clean Water Act on the water quality of urban estuaries, dissolved trace metals and phosphate concentrations were determined in surface waters collected along the Hudson River estuary between 1995 and 1997 and compared with samples collected in the mid-1970s by Klinkhammer and Bender. The median concentrations along the estuary have apparently declined 36--56% for Cu, 55--89% for Cd, 53--85% for Ni, and 53--90% for Zn over a period of 23 years. These reductions appear to reflect improvements in controlling discharges from municipal and industrial wastewater treatment plants since the Clean Water Act was enacted in 1972. In contrast, levels of dissolved nutrients (PO{sub 4}) have remained relatively constant during the same period of time, suggesting that wastewater treatment plant improvements in the New York/New Jersey Metropolitan area have not been as effective at reducing nutrient levels within the estuary. While more advanced wastewater treatment could potentially reduce the levels of Ag and PO{sub 4} along the estuary, these improvements would have a more limited effect on the levels of other trace metals.

  15. Does boat traffic cause displacement of fish in estuaries?

    PubMed

    Becker, Alistair; Whitfield, Alan K; Cowley, Paul D; Järnegren, Johanna; Næsje, Tor F

    2013-10-15

    Estuaries are increasingly under threat from a variety of human impacts. Recreational and commercial boat traffic in urban areas may represent a significant disturbance to fish populations and have particularly adverse effects in spatially restricted systems such as estuaries. We examined the effects of passing boats on the abundance of different sized fish within the main navigation channel of an estuary using high resolution sonar (DIDSON). Both the smallest (100-300 mm) and largest (>501 mm) size classes had no change in their abundance following the passage of boats. However, a decrease in abundance of mid-sized fish (301-500 mm) occurred following the passage of boats. This displacement may be attributed to a number of factors including noise, bubbles and the rapidly approaching object of the boat itself. In highly urbanised estuarine systems, regular displacement by boat traffic has the potential to have major negative population level effects on fish assemblages.

  16. Spring climate and salinity in the San Francisco Bay Estuary

    USGS Publications Warehouse

    Cayan, Daniel R.; Peterson, David H.

    1993-01-01

    Salinity in the San Francisco Bay Estuary almost always experiences its yearly maximum during late summer, but climate variability produces marked interannual variations. The atmospheric circulation pattern impacts the estuary primarily through variations of runoff from rainfall and snowmelt from the Sierra Nevada and, secondarily, through variations in the near-surface salinity in the coastal ocean. While winter precipitation is the primary influence upon salinity in the estuary, spring climate variations also contribute importantly to salinity fluctuations. Spring atmospheric circulation influences both the magnitude and the timing of freshwater flows, through anomalies of precipitation and temperature. To help discriminate between the effects of these two influences, the record is divided into subsets according to whether spring conditions in the region are cool and wet, warm and wet, cool and dry, or warm and dry. Warm springs promote early snowmelt-driven flows, and cool springs result in delayed flows. In addition to effects of winter and spring climate variability operating on the watershed, there are more subtle effects that are transmitted into the estuary from the coastal ocean. These influences are most pronounced in cool and dry springs with high surface salinity (SS) in the coastal ocean versus cool and wet springs with low SS in the coastal ocean. A transect of SS records at stations from the mouth to the head of the bay suggests that the coastal ocean anomaly signal is attenuated from the mouth to the interior of the estuary. In contrast, a delayed, postsummer signal caused by winter and spring runoff variations from the upstream watershed are most pronounced at the head of the estuary and attenuate toward the mouth.

  17. Estuary-ocean connectivity: fast physics, slow biology.

    PubMed

    Raimonet, Mélanie; Cloern, James E

    2016-11-01

    Estuaries are connected to both land and ocean so their physical, chemical, and biological dynamics are influenced by climate patterns over watersheds and ocean basins. We explored climate-driven oceanic variability as a source of estuarine variability by comparing monthly time series of temperature and chlorophyll-a inside San Francisco Bay with those in adjacent shelf waters of the California Current System (CCS) that are strongly responsive to wind-driven upwelling. Monthly temperature fluctuations inside and outside the Bay were synchronous, but their correlations weakened with distance from the ocean. These results illustrate how variability of coastal water temperature (and associated properties such as nitrate and oxygen) propagates into estuaries through fast water exchanges that dissipate along the estuary. Unexpectedly, there was no correlation between monthly chlorophyll-a variability inside and outside the Bay. However, at the annual scale Bay chlorophyll-a was significantly correlated with the Spring Transition Index (STI) that sets biological production supporting fish recruitment in the CCS. Wind forcing of the CCS shifted in the late 1990s when the STI advanced 40 days. This shift was followed, with lags of 1-3 years, by 3- to 19-fold increased abundances of five ocean-produced demersal fish and crustaceans and 2.5-fold increase of summer chlorophyll-a in the Bay. These changes reflect a slow biological process of estuary-ocean connectivity operating through the immigration of fish and crustaceans that prey on bivalves, reduce their grazing pressure, and allow phytoplankton biomass to build. We identified clear signals of climate-mediated oceanic variability in this estuary and discovered that the response patterns vary with the process of connectivity and the timescale of ocean variability. This result has important implications for managing nutrient inputs to estuaries connected to upwelling systems, and for assessing their responses to changing

  18. Hierarchical Mapping of Landforms along the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Cannon, C. M.

    2015-12-01

    Mapping and hierarchical classification of landforms along the Columbia River estuary provides insight into formative geologic, hydrologic, and biologic processes and their associated ecosystems, thereby aiding assessment of future trajectories and restoration approaches. The Columbia River Estuary Ecosystem Classification includes an inventory of landforms along 230 km of riverine estuary between the Pacific Ocean and Bonneville Dam in Oregon and Washington, USA. Landforms were mapped by interpretation of lidar topography supplemented with high-resolution bathymetry, aerial photographs, soil maps, and historical maps. Groupings of landforms were assigned to formative process regimes. These landform groupings relate ecosystems to geophysical processes. Assessment of historical changes to the processes that form and maintain landforms thus has implications for the types of ecosystems that can form and persist along the estuary. The estuary was historically a complex system of channels with a floodplain dominated by extensive tidal wetlands in the lower reaches and backswamp lakes and wetlands in upper reaches. Natural levees flank most channels in the upper reaches, locally including areas of ridge and swale topography and crevasse splays that intrude into backswamps. Other Holocene process regimes affecting floodplain morphology have included volcanogenic deltas, tributary fans, eolian dunes, and landslides. Pre-Holocene landforms are locally prominent and include ancient fluvial deposits and bedrock. Historical changes to streamflow regimes, floodplain isolation, and direct anthropogenic disturbance have resulted in channel narrowing and limited the amount of floodplain that can be shaped by flowing water. Floodplain isolation has caused relative subsidence of tidal floodplains along much of the lower estuary. Most extant landforms are on trajectories strongly influenced by humans and new landforms are mostly created by humans.

  19. Where do the Nutrients go in Tropical Estuaries?

    NASA Astrophysics Data System (ADS)

    Ramachandran, R., VI

    2015-12-01

    Anthropogenic inputs of nutrients to the estuaries have rapidly increased during last couple of decades, resulting in deterioration of coastal water quality at regional scales. It is imperative to assess and quantify the ability of coastal systems to utilize, transport, and transform the 'excess' dissolved nutrients that enter the coast via land based activities. A LOICZ biogeochemical mass budget model was applied to the largest Indian estuary - the Ganges (Hooghly). Model studies indicate that despite high nutrient concentrations, the estuary remained net heterotrophic throughout the year. However if suspended particulate matter (SPM) was considered while estimating net metabolism, the system was net autotrophic. This model clearly highlights the influence of adsorption and desorption of nutrient and buffering action of SPM on nutrient dynamics under varying environmental conditions. Case studies from estuaries (e.g. Godavari and Tapi) and lagoon systems(Chilika and Vembanad) of India with differing levels of discharge and pollution were studied to determine the role of SPM on the trophic shift of these systems. Biogeochemical mass budget for all the systems suggested that in spite of high nutrient availability, high load of SPM (>100 mg L-1) controlled the trophic state and nutrient dynamics of a system. Indian estuaries and lagoons are predominantly heterotrophic, due to increasing anthrpogenic pressures from land based nutrient loading. The lagoon systems such as Chilika and Vembanad were predominantly heterotrophic and are a major source of phosphorus to the coastal waters. Overall, the source/sink characteristics of a system with respect to the adjacent coastal ocean were dependent on the in-situ biogeochemical processes (release, uptake and burial) and the residence time. The results further suggest that Hooghly estuary acts as a conduit of land-derived nutrients to the coastal ocean.

  20. Mud transport in the Microtidal San Jacinto Estuary

    NASA Astrophysics Data System (ADS)

    Salehi, M.

    2013-12-01

    The overall objective of this research is to better understand the sediment transport processes in the microtidal San Jacinto Estuary (near Houston, TX) under variable hydrologic conditions. A numerical modeling approach is selected to answer the main question of; how will changes in freshwater input change the sedimentation pattern of the region? In this computational work, no new numerical method or code is developed, but rather an existing technology (MIKE 3D developed by DHI) is used to build a virtual San Jacinto Estuary laboratory where boundary conditions could be applied and altered to the domain to observe the general functional response of the system. Two synthetic freshwater inflows, simulating dry and wet conditions, were used in the numerical modeling experiments. Simulations showed that change in freshwater inflow has major impact on the salinity magnitude within the estuary. In dry conditions, the 5 ppt isohaline traveled all the way upstream of Morgans Point, almost to the confluence of San Jacinto River with Buffalo Bayou. During the extreme wet weather conditions, the 5 ppt isohaline of the surface water was pushed almost as far as Galveston Island. Overall erosion and deposition pattern showed little change between extreme dry and wet years. In general, part of the shallow areas experienced erosion whereas deeper parts of the estuary were under deposition. High freshwater inflow caused around 30% higher deposition in some parts of the channel compared with the low freshwater. Furthermore, examining the mass balance within the whole San Jacinto Estuary showed that around 28% of the input sediment was flushed out during the wet season. But in dry season, not only no sediment left the domain but also it received around 17% of the total available sediment within the estuary from the shelf.

  1. Mud transport in the Microtidal San Jacinto Estuary

    NASA Astrophysics Data System (ADS)

    Salehi, M.; Strom, K. B.

    2012-12-01

    The overall objective of this research is to better understand the sediment transport processes in the microtidal San Jacinto Estuary (near Houston, TX) under variable hydrologic conditions. A numerical modeling approach is selected to answer the main question of; how will changes in freshwater input change the sedimentation pattern of the region? In this computational work, no new numerical method or code is developed, but rather an existing technology (MIKE 3D developed by DHI) is used to build a virtual San Jacinto Estuary laboratory where boundary conditions could be applied and altered to the domain to observe the general functional response of the system. Two synthetic freshwater inflows, simulating dry and wet conditions, were used in the numerical modeling experiments. Simulations showed that change in freshwater inflow has major impact on the salinity magnitude within the estuary. In dry conditions, the 5 ppt isohaline traveled all the way upstream of Morgans Point, almost to the confluence of San Jacinto River with Buffalo Bayou. During the extreme wet weather conditions, the 5 ppt isohaline of the surface water was pushed almost as far as Galveston Island. Overall erosion and deposition pattern showed little change between extreme dry and wet years. In general, part of the shallow areas experienced erosion whereas deeper parts of the estuary were under deposition. High freshwater inflow caused around 30% higher deposition in some parts of the channel compared with the low freshwater. Furthermore, examining the mass balance within the whole San Jacinto Estuary showed that around 28% of the input sediment was flushed out during the wet season. But in dry season, not only no sediment left the domain but also it received around 17% of the total available sediment within the estuary from the shelf.

  2. Radium isotopes in the Orinoco estuary and Eastern Caribbean Sea

    SciTech Connect

    Moore, W.S.; Todd, J.F. )

    1993-02-15

    Radium isotopes provide a means of identifying the source of freshened waters in the ocean and determining the time elapsed since these waters were in the estuary. The authors present evidence that during April, waters from the Amazon mixing zone pass within 50 km of the mouth of the Orinoco River. These Amazon waters are characterized by a lower [sup 228]Ra/[sup 226]Ra activity ratio (AR) than are waters from the Orinoco at similar salinities. During autumn, the increased discharge of the Orinoco displaces the freshened Amazon waters seaward, yet the two can be distinguished clearly. Within the Caribbean Sea, waters of Orinoco origin carry a characteristic radium signature including excess activities of [sup 224]Ra. This isotope may be used to estimate the time elapsed since the waters were removed from contact with sediments. Current speeds based on [sup 224]Ra dating ranged from 15 to 33 cm/s during April. The radium isotopes also provide an assessment of sediment mixing in the estuary. During low discharge (April), considerable mixing of older sediment by physical or biological processes or dredging maintained high activities of [sup 228]Ra in the estuary and produced the highest [sup 228]Ra/[sup 226]Ra AR's yet measured in any estuary. During high discharge (September), a large fraction of the [sup 228]Ra was derived from desorption from fresh sediment rather than mixing of older sediments. Activities of [sup 224]Ra were high in the estuary during both high and low discharge, indicating that considerable mixing of recently introduced sediment must occur during each period. During April, [sup 224]Ra and [sup 228]Ra activities in the water were about equal, indicating that most of the sediment being resuspended had been stored in the estuary long enough to reestablish radioactive equilibrium in the [sup 232]Th decay series (i.e., 20 years). 19 refs., 11 figs., 3 tabs.

  3. Hydrology of major estuaries and sounds of North Carolina

    USGS Publications Warehouse

    Giese, G.L.; Wilder, Hugh B.; Parker, Garald G.

    1985-01-01

    Hydrology-related problems associated with North Carolina 's major estuaries and sounds include contamination of some estuaries with municipal and industrial wastes and drainage from adjacent, intensively farmed areas, and nuisance-level algal blooms. In addition, there is excessive shoaling in some navigation channels, salt-water intrusion into usually fresh estuarine reaches, too high or too-low salinities in nursery areas for various estuarine species, and flood damage due to hurricanes. The Cape Fear River is the only major North Carolina estuary having a direct connection to the sea. Short-term flow throughout most of its length is dominated by ocean tides. Freshwater entering the major estuaries is, where not contaminated, of acceptable quality for drinking with minimum treatment. However, iron concentrations in excess of 0.3 milligrams per liter sometimes occur and water draining from swampy areas along the Coastal Plain is often highly colored, but these problems may be remedied with proper treatment. Nuisance-level algal blooms have been a recurring problem on the lower estuarine reaches of the Neuse, Tar-Pamlico, and Chowan Rivers where nutrients (compounds of phosphorous and nitrogen) are abundant. The most destructive blooms tend to occur in the summer months during periods of low freshwater discharge and relatively high water temperatures. Saltwater intrusion occurs from time to time in all major estuaries except the Roanoke River, where releases from Roanoke Rapids Lake and other reservoirs during otherwise low-flow periods effectively block saline water from the estuary. New shoaling materials found in the lower channelized reaches of the Cape Fear and Northeast Cape Fear Rivers are primarily derived, not from upstream sources, but from nearby shore erosion, from slumping of material adjacent to the dredged channels, from old spoil areas, or from ocean-derived sediments carried upstream by near-bottom density currents.

  4. Rhenium and Molybdenum in Rivers and Estuaries.

    NASA Astrophysics Data System (ADS)

    Walker, B. D.; Peucker-Ehrenbrink, B.

    2004-12-01

    Due to their redox-sensitive nature, the geochemical cycles of Re and Mo are linked to the global organic carbon cycle. Reducing sediments constitute a globally important sink and weathering of organic-rich sediments is responsible for a large portion of the Re and - to a lesser extent - Mo flux to the oceans (Colodner et al., 1993; Jaffe et al., 2002). Riverine concentrations of Re and Mo are a function of the river basin lithology, but are also likely to be affected by anthropogenic contributions (Colodner et al., 1995). Current estimates of global natural riverine Re flux are restricted to single analyses of four major rivers, which characterize only 23%\\ of the global freshwater flux (Colodner et al., 1993). Annual variability of Re and Mo concentrations in rivers has not been studied. A single study of Re concentrations along the salinity gradient of the Amazon shelf is suggestive of conservative mixing, but scatter in the data do not allow to exclude the possibility of Re addition in the low-salinity end of the profile (Colodner et al., 1993). Careful evaluation of samples from the Hudson River estuary using a variety of extraction techniques indicates that spike-sample equilibration was not fully achieved using commonly used methods. We have therefore developed a simple, clean and efficient method of extracting Re from filtered water samples. Our method utilizes syringe filtration, prolonged heating to achieve spike-sample equilibration, batch equilibration with TEVA resin, and extraction of Re and Mo using syringe filtration. Rhenium concentrations in the Hudson, Housatonic and Connecticut rivers are 38 pM, 6.6 pM and 14 pM, respectively, much higher than the estimated global average of 2.1 pM (Colodner et al., 1993). Molybdenum concentrations are 4.6 nM, 5.5 nM, 7.8 nM, respectively. These rivers drain basins of Precambrian basement as well as predominantly Paleozoic sediments and have been substantially urbanized. Data for a salinity profile along the

  5. Impacts of pesticides in a Central California estuary.

    PubMed

    Anderson, Brian; Phillips, Bryn; Hunt, John; Siegler, Katie; Voorhees, Jennifer; Smalling, Kelly; Kuivila, Kathy; Hamilton, Mary; Ranasinghe, J Ananda; Tjeerdema, Ron

    2014-03-01

    Recent and past studies have documented the prevalence of pyrethroid and organophosphate pesticides in urban and agricultural watersheds in California. While toxic concentrations of these pesticides have been found in freshwater systems, there has been little research into their impacts in marine receiving waters. Our study investigated pesticide impacts in the Santa Maria River estuary, which provides critical habitat to numerous aquatic, terrestrial, and avian species on the central California coast. Runoff from irrigated agriculture constitutes a significant portion of Santa Maria River flow during most of the year, and a number of studies have documented pesticide occurrence and biological impacts in this watershed. Our study extended into the Santa Maria watershed coastal zone and measured pesticide concentrations throughout the estuary, including the water column and sediments. Biological effects were measured at the organism and community levels. Results of this study suggest the Santa Maria River estuary is impacted by current-use pesticides. The majority of water samples were highly toxic to invertebrates (Ceriodaphnia dubia and Hyalella azteca), and chemistry evidence suggests toxicity was associated with the organophosphate pesticide chlorpyrifos, pyrethroid pesticides, or mixtures of both classes of pesticides. A high percentage of sediment samples were also toxic in this estuary, and sediment toxicity occurred when mixtures of chlorpyrifos and pyrethroid pesticides exceeded established toxicity thresholds. Based on a Relative Benthic Index, Santa Maria estuary stations where benthic macroinvertebrate communities were assessed were degraded. Impacts in the Santa Maria River estuary were likely due to the proximity of this system to Orcutt Creek, the tributary which accounts for most of the flow to the lower Santa Maria River. Water and sediment samples from Orcutt Creek were highly toxic to invertebrates due to mixtures of the same pesticides measured

  6. Analytical solution of tidal dynamics in convergent estuaries: A review

    NASA Astrophysics Data System (ADS)

    Cai, Huayang; Savenije, Hubert H. G.; Toffolon, Marco

    2013-04-01

    In this contribution we focus on the tidal wave propagation in convergent estuaries, where the cross-sectional area varies approximately as an exponential function along the estuary axis. This kind of estuarine geometry, which is observed in coastal plain estuaries all over the world, including widely studied tidal estuaries such as the Scheldt in the Netherlands, Thames in the UK, Delaware in the USA, can produce amplification or damping of the tidal wave: if the effect of convergence is stronger than the effect of friction, the wave is amplified; if friction is stronger than convergence, the wave is damped. Since real estuaries can experience amplification and damping in different regions, depending primarily on local depth and convergence, a multiple-reach approach is typically required. It has been recently shown that a fully analytical solution for the one-dimensional tidal hydrodynamics can be obtained by solving a set of four implicit analytical equations, i.e., the damping, the phase lag, the scaling and the celerity equations (Toffolon et al., 2006; Savenije et al., 2008; Cai et al., 2012). Such a solution can be applied locally and represents a valuable tool to describe the tidal dynamics in an affordable yet reliable way. Moreover, it provides a theoretical framework that can be used to compare the different assumptions, like for instance the linearization of the friction term, which are exploited in previously derived analytical solutions. It is found that the main differences between the different approaches lie in: 1) the account of local variability (e.g., the depth), 2) the different approximations of the friction term, 3) the account of asymptotic behaviour. The purpose of this review is hence to summarize common features and main differences among the various analytical solutions and finally enhance our understanding of tidal wave propagation in estuaries. References Cai, H., H. H. G. Savenije, and M. Toffolon (2012), A new analytical framework

  7. The Ob Estuary (Kara Sea) Coastal Dynamics Interannual Variability Assessment

    NASA Astrophysics Data System (ADS)

    Kopa-Ovdienko, N.; Volobueva, N.; Ogorodov, S.

    2012-04-01

    There are several promising gas fields in the Ob Estuary. For their development comprehensive research, including coastal dynamics assessment, is required. To estimate current and speak about future coastal dynamics rates we need to investigate its interannual variability connecting it with variability of major coastal dynamics factors. It is known that in this region one of the main coastal dynamics factors is wave action, which, in turn, depends on wind velocity and direction. Wind data for ice-free period were derived from nearby hydro-meteorological stations. The research was conducted for two sections of the Ob Estuary coast. One section is located on the eastern coast of the estuary (Taz peninsula); the other is located on the western one (Yamal peninsula). Each of these sections is 10 km length. For key-sites of the coast wave-dangerous rhumbs were determined. For ice-free period of each year accumulated summer storm duration (ASSD) - number of hours with strong winds (≥10 m/s) from wave-dangerous directions - was calculated for both sections of coast. Supposing that coast retreat rate is proportional to number of hours with strong winds from wave-dangerous rhumbs, we can approximately assess interannual variability of coast retreat rate. Our research revealed that: 1)There are significant (from hours to a few hundreds of hours) differences in ASSD from year to year due to short ice-free period and high variability of wind velocity and direction. So, we can expect sharp interannual differences in coastal retreat rate. 2)The duration of strong winds from wave-dangerous rhumbs during ice-free period is more on the eastern coast of the estuary than on the western. This goes from the predominance of northern and northwestern winds during ice-free period. These winds cause waves leading to coastal erosion on the eastern coast of estuary and don't cause such waves on the western one. However, we can't draw conclusions about the comparative rates of coastal

  8. Modeling pesticide fate in a small tidal estuary

    USGS Publications Warehouse

    McCarthy, A.M.; Bales, J.D.; Cope, W.G.; Shea, D.

    2007-01-01

    The exposure analysis modeling system (EXAMS), a pesticide fate model developed by the U.S. Environmental Protection Agency, was modified to model the fate of the herbicides atrazine and metolachlor in a small tidally dominated estuary (Bath Creek) in North Carolina, USA where freshwater inflow accounts for only 3% of the total flow. The modifications simulated the changes that occur during the tidal cycle in the estuary, scenarios that are not possible with the original EXAMS model. Two models were created within EXAMS, a steady-state model and a time-variant tidally driven model. The steady-state model accounted for tidal flushing by simply altering freshwater input to yield an estuary residence time equal to that measured in Bath Creek. The tidal EXAMS model explicitly incorporated tidal flushing by modifying the EXAMS code to allow for temporal changes in estuary physical attributes (e.g., volume). The models were validated with empirical measurements of atrazine and metolachlor concentrations in the estuary shortly after herbicide application in nearby fields and immediately following a rain event. Both models provided excellent agreement with measured concentrations. The steady-state EXAMS model accurately predicted atrazine concentrations in the middle of the estuary over the first 3 days and under-predicted metolachlor by a factor of 2-3. The time-variant, tidally driven EXAMS model accurately predicted the rise and plateau of both herbicides over the 6-day measurement period. We have demonstrated the ability of these modified EXAMS models to be useful in predicting pesticide fate and exposure in small tidal estuaries. This is a significant improvement and expansion of the application of EXAMS, and given the wide use of EXAMS for surface water quality modeling by both researchers and regulators and the ability of EXAMS to interface with terrestrial models (e.g., pesticide root zone model) and bioaccumulation models, we now have an easily-accessible and

  9. Abandoned Channel Fill Sequences in Tidal Estuaries

    NASA Astrophysics Data System (ADS)

    Gray, A. B.; Pasternack, G. B.; Goni, M. A.; Watson, E. B.

    2014-12-01

    This study proposes a modification of the current model for abandoned channel fill stratigraphy produced in unidirectional flow river reaches to incorporate seasonal tidal deposition. Evidence supporting this concept came from a study of two consecutive channel abandonment sequences in Ropers Slough of the lower Eel River Estuary in northern California. Aerial photographs showed that Ropers Slough was abandoned around 1943, reoccupied after the 1964 flood, and abandoned again in 1974 with fill continuing to the present. Planform geomorphic characteristics derived from these images were used in conjunction with sub-cm resolution stratigraphic analyses to describe the depositional environment processes and their resultant sedimentary deposits. Results showed that both abandonment sequences recorded quasi-annual scale fluvial/tidal deposition couplets. In both cases tidal deposits contained very little sand, and were higher in organic and inorganic carbon content than the sandier fluvial through-flow deposits. However, the two abandonment fills differed significantly in terms of the temporal progression of channel narrowing and fluvial sediment deposition characteristics. The first abandonment sequence led to a more rapid narrowing of Ropers Slough and produced deposits with a positive relationship between grain size/deposit thickness and discharge. The second abandonment resulted in a much slower narrowing of Ropers Slough and generally thinner fluvial deposits with no clear relationship between grain size/deposit thickness and discharge. The δ13C values and organic nitrogen to organic carbon ratios of deposits from the first phase overlapped with Eel River suspended sediment characteristics found for low flows (1-5 times mean discharge), while those of the second phase were consistent suspended sediment from higher flows (7-10 times mean discharge). The abandoned channel fill sequences appeared to differ due to the topographic steering of bed sediment transport and

  10. Large-scale spatial patterns in estuaries: estuarine macrobenthic communities in the Schelde estuary, NW Europe

    NASA Astrophysics Data System (ADS)

    Ysebaert, T.; Herman, P. M. J.; Meire, P.; Craeymeersch, J.; Verbeek, H.; Heip, C. H. R.

    2003-05-01

    Few macrobenthic studies have dealt simultaneously with the two major gradients in estuarine benthic habitats: the salinity gradient along the estuary (longitudinal) and the gradients from high intertidal to deep subtidal sites (vertical gradient). In this broad-scale study, a large data set (3112 samples) of the Schelde estuary allowed a thorough analysis of these gradients, and to relate macrobenthic species distributions and community structure to salinity, depth, current velocities and sediment characteristics. Univariate analyses clearly revealed distinct gradients in diversity, abundance, and biomass along the vertical and longitudinal gradients. In general, highest diversity and biomass were observed in the intertidal, polyhaline zone and decreased with decreasing salinity. Abundance did not show clear trends and varied between spring and autumn. In all regions, very low values for all measures were observed in the subtidal depth strata. Abundance in all regions was dominated by both surface deposit feeders and sub-surface deposit feeders. In contrast, the biomass of the different feeding guilds showed clear gradients in the intertidal zone. Suspension feeders dominated in the polyhaline zone and showed a significant decrease with decreasing salinity. Surface deposit feeders and sub-surface deposit feeders showed significantly higher biomass values in the polyhaline zone as compared with the mesohaline zone. Omnivores showed an opposite trend. Multivariate analyses showed a strong relationship between the macrobenthic assemblages and the predominant environmental gradients in the Schelde estuary. The most important environmental factor was depth, which reflected also the hydrodynamic conditions (current velocities). A second gradient was related to salinity and confirms the observations from the univariate analyses. Additionally, sediment characteristics (mud content) explained a significant part of the macrobenthic community structure not yet explained by

  11. The stirling engine for vehicle propulsion

    NASA Technical Reports Server (NTRS)

    Kuhlman, P.

    1978-01-01

    The performance data of experimental Stirling engines are considered along with questions of exhaust-gas composition, engine noise, engine volume and weight, engine control, and the engine-starting process. The Stirling engine can use practically any liquid or gaseous fuel for its operation. It is found that technically a use of the Stirling engine in motor vehicles is feasible. Economic questions related to an introduction of the Stirling engine are discussed along with possible new developments which could improve the economic situation in favor of a use of Stirling engine.

  12. Feasibility of remote sensing benthic microalgae

    NASA Technical Reports Server (NTRS)

    Zingmark, R. G.

    1979-01-01

    Results of data analyses from multispectral scanning data are presented. The data was collected in July 1977 for concentration of chlorophyll in benthic microalgae (mainly diatoms) on an estuary mudflat.

  13. Environmental management of a highly impacted, urbanized tropical estuary: rehabilitation and restoration

    NASA Astrophysics Data System (ADS)

    Thorhaug, A.

    1980-03-01

    The principles of the dynamics and interrelationships within the dominant subtropical and tropical Caribbean seagrass community have been studied previously before, during, and after impact. From these and scores of observations of damage and recovery patterns in Thalassia ecosystems, a sense of management recovery strategy has emerged. Artificial restoring of Thalassia testudinum seeds into areas cut off from stock (fruit, seeds) appeared feasible on a large scale after the Turkey Point (Biscayne Bay, Miami, Florida) restoration and test sampling throughout North Biscayne Bay. Two large-scale seeding attempts were made; after 11 months they compared favorably with Turkey Point specimens with regard to growth parameters, despite the turbidity and other persistent pollution. Thus, the possible areas in which Thalassia seed restoration can be used has increased to include estuaries of multiple impact still in various stages of recovery after physical and sewage pollution. This technique should be especially useful to “developing” nations where important nearshore fisheries nurseries based on Thalassia ecosystems have been heavily damaged and now lie barren. Man's impact on the estuary where seed restoration was attempted includes the following activities: 50% of the bay bottom directly dredged or filled (leaving much unconsolidated sediment); 50 million gallons of domestic waste dumped directly into a low flushing part of the bay for 20 years; seven major causeways transecting the bay, restricting circulation and flushing; two artificial inlets made into navigational channels; freshwater sheet flow drastically changed due to channelization by flood-control canals; urban runoff from a million people entering the bay. Most of the impacts have now abated; however, their long-term effects remain.

  14. Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Ebberts, Blaine D.; Tortorici, Cathy; Yerxa, Tracey; Leary, J.; Skalski, John R.

    2008-02-05

    The purpose ofthis document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision-making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows. 1. Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. 2. Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. 3. Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. 4. Maintain the food web to benefit salmonid performance. 5. Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. In conclusion, the estuary RME effort is designed to meet the research and monitoring needs of the estuary Program using an adaptive management process. Estuary RME's success and usefulness will depend on the actual conduct of adaptive management, as embodied in the objectives, implrementation, data, reporting, and synthesis, evaluation, and decision-making described herein.

  15. The recovery of oyster (Saccostrea glomerata) populations in Sydney estuary (Australia).

    PubMed

    Birch, G F; Scammell, M S; Besley, C H

    2014-01-01

    The current work documented a significant and widespread increase in the abundance of the Sydney rock oyster Saccostrea glomerata, in Sydney estuary (Australia) by undertaking surveys of oyster density in the estuary in 1989 and annually from 1994 to 2006. Oyster density at six control sites located in nearby National Parks unaffected by boating and stormwater discharges were compared to 17 study sites widely distributed within Sydney estuary. No oyster populations were evident in Sydney estuary in 1989; however, by 1994 oysters had colonised areas of the lower and central estuary and by 2002 densities were statistically similar to control sites. The timing of estuary-wide increases in oyster abundance suggests that the partial banning of tributyltin in 1989 for vessels under 25 m long may have played a major role in the increase of S. glomerata in this estuary.

  16. Observation of saltwater intrusion and ETM dynamics in a stably stratified estuary: the Yangtze Estuary, China.

    PubMed

    Wan, Yuanyang; Zhao, Dezhao

    2017-02-01

    Spatial and temporal measurement data describing spring-neap variations of velocity, salinity, and suspended sediment concentration (SSC) in the North Passage Deepwater Navigational Channel (DNC) of the Yangtze Estuary, China, were obtained in the wet season of 2012. These data were collected in the middle of the DNC and apparently document the formation of a rather stable density stratification interface and salt wedge, especially during neap tides and slack waters. The convergent zone of residual currents, salinity transport, and sediment transport during neap and spring tides oscillates in the middle and lower reach of the DNC. It encourages the formation of a near-bed high-SSC layer, which favours siltation in the dredged channel. Both the near-bed gradient Richardson number and the bulk/layer Richardson number vary dramatically from around zero to several hundred from spring to neap tides. Stratification and turbulence damping effects near the estuarine turbidity maximum (ETM) area induce the upper half (near water surface) of the water body to be ebb-dominant and the lower part (near-bed) to be flood-dominant, which is a previously undocumented phenomenon in this region. These data reveal that the residual pattern of currents, salt flux and sediment flux are of critical differences in a stratified estuary, and that the salinity-induced baroclinic pressure gradient is a major factor controlling the vertical velocity structure. In addition, field observations indicate that the salinity and sediment transport of residuals generated by internal tidal asymmetry plays a dominant role in maintaining a stable density stratification interface near the estuarine front.

  17. Bin Set 1 Calcine Retrieval Feasibility Study

    SciTech Connect

    R. D. Adams; S. M. Berry; K. J. Galloway; T. A. Langenwalter; D. A. Lopez; C. M. Noakes; H. K. Peterson; M. I. Pope; R. J. Turk

    1999-10-01

    At the Department of Energy's Idaho Nuclear Technology and Engineering Center, as an interim waste management measure, both mixed high-level liquid waste and sodium bearing waste have been solidified by a calculation process and are stored in the Calcine Solids Storage Facilities. This calcined product will eventually be treated to allow final disposal in a national geologic repository. The Calcine Solids Storage Facilities comprise seven ''bit sets.'' Bin Set 1, the first to be constructed, was completed in 1959, and has been in service since 1963. It is the only bin set that does not meet current safe-shutdown earthquake seismic criteria. In addition, it is the only bin set that lacks built-in features to aid in calcine retrieval. One option to alleviate the seismic compliance issue is to transport the calcine from Bin Set 1 to another bin set which has the required capacity and which is seismically qualified. This report studies the feasibility of retrieving the calcine from Bi n Set 1 and transporting it into Bin Set 6 which is located approximately 650 feet away. Because Bin Set 1 was not designed for calcine retrieval, and because of the high radiation levels and potential contamination spread from the calcined material, this is a challenging engineering task. This report presents preconceptual design studies for remotely-operated, low-density, pneumatic vacuum retrieval and transport systems and equipment that are based on past work performed by the Raytheon Engineers and Constructors architectural engineering firm. The designs presented are considered feasible; however, future development work will be needed in several areas during the subsequent conceptual design phase.

  18. Tribal Utility Feasibility Study

    SciTech Connect

    Engel, R. A.; Zoellick, J. J.

    2007-06-30

    The Schatz Energy Research Center (SERC) assisted the Yurok Tribe in investigating the feasibility of creating a permanent energy services program for the Tribe. The original purpose of the DOE grant that funded this project was to determine the feasibility of creating a full-blown Yurok Tribal electric utility to buy and sell electric power and own and maintain all electric power infrastructure on the Reservation. The original project consultant found this opportunity to be infeasible for the Tribe. When SERC took over as project consultant, we took a different approach. We explored opportunities for the Tribe to develop its own renewable energy resources for use on the Reservation and/or off-Reservation sales as a means of generating revenue for the Tribe. We also looked at ways the Tribe can provide energy services to its members and how to fund such efforts. We identified opportunities for the development of renewable energy resources and energy services on the Yurok Reservation that fall into five basic categories: • Demand-side management – This refers to efforts to reduce energy use through energy efficiency and conservation measures. • Off-grid, facility and household scale renewable energy systems – These systems can provide electricity to individual homes and Tribal facilities in areas of the Reservation that do not currently have access to the electric utility grid. • Village scale, micro-grid renewable energy systems - These are larger scale systems that can provide electricity to interconnected groups of homes and Tribal facilities in areas of the Reservation that do not have access to the conventional electric grid. This will require the development of miniature electric grids to serve these interconnected facilities. • Medium to large scale renewable energy development for sale to the grid – In areas where viable renewable energy resources exist and there is access to the conventional electric utility grid, these resources can be

  19. Planetary engineering

    NASA Technical Reports Server (NTRS)

    Pollack, James B.; Sagan, Carl

    1991-01-01

    Assuming commercial fusion power, heavy lift vehicles and major advances in genetic engineering, the authors survey possible late-21st century methods of working major transformations in planetary environments. Much more Earthlike climates may be produced on Mars by generating low freezing point greenhouse gases from indigenous materials; on Venus by biological conversion of CO2 to graphite, by canceling the greenhouse effect with high-altitude absorbing fine particles, or by a sunshield at the first Lagrangian point; and on Titan by greenhouses and/or fusion warming. However, in our present state of ignorance we cannot guarantee a stable endstate or exclude unanticipated climatic feedbacks or other unintended consequences. Moreover, as the authors illustrate by several examples, many conceivable modes of planetary engineering are so wasteful of scarce solar system resources and so destructive of important scientific information as to raise profound ethical issues, even if they were economically feasible, which they are not. Global warming on Earth may lead to calls for mitigation by planetary engineering, e.g., emplacement and replenishment of anti-greenhouse layers at high altitudes, or sunshields in space. But here especially we must be concerned about precision, stability, and inadvertent side-effects. The safest and most cost-effective means of countering global warming - beyond, e.g., improved energy efficiency, CFC bans and alternative energy sources - is the continuing reforestation of approximately 2 times 107 sq km of the Earth's surface. This can be accomplished with present technology and probably at the least cost.

  20. The MRIS feasibility study

    NASA Technical Reports Server (NTRS)

    Neece, Robert T.; Cross, Aubrey E.; Schrader, James H.

    1993-01-01

    The Microwave Reflectometer Ionization Sensor (MRIS) is an instrument being developed for use in detecting and ranging of electron density layers in the reentry plasma of a space transfer vehicle. The rationale for the selection of the Double Sideband Suppressed Carrier (DSBSC) system used in the feasibility study for the MRIS is presented. A 25 GHz single-oscillator system and a 220 GHz double-oscillator system are described. The 25 GHz system was constructed and tested in the laboratory and test results are presented. As developed, the system employs a sideband spacing of 160 MHz. Based on an estimated electromagnetic wave velocity in the plasma, a round-trip phase shift measurement accuracy of +/- 7.6 degrees was required for the desired +/- 1/2 cm distance measurement accuracy. The interaction of parallel ground and reflecting planes produces interference that prevents the basic DSBSC system from meeting the accuracy goal so a frequency modulation was added to the system to allow averaging of the measured phase deviation. With an FM deviation of +/- 1 GHz, laboratory measurements were made for distances from 5 to 61 cm tip free space. Accounting for the plasma velocity factor, 82 percent of the data were equal to or better than the desired accuracy. Based on this measured result a sideband spacing to 250 MHz could be expected to yield data approximately 96 percent within the accuracy goal.

  1. Estuarine habitat utilization by birds in Yaquina Estuary, Oregon

    EPA Science Inventory

    A wide variety of bird species are highly dependent on intertidal wetland habitats. Because of this dependency, birds are viewed as important indicators of wetland structure and function. Wetlands in Yaquina Bay along with the tidal wetlands in other Pacific coastal estuaries r...

  2. Forward for book entitled "Estuaries: Classification, Ecology, and Human Impacts"

    EPA Science Inventory

    The author was introduced to the science of estuaries as a graduate student in the early 1980s, studying the ecology of oyster populations in Chesapeake Bay. To undertake this research, he needed to learn not only about oyster biology, but also about the unique physical and chemi...

  3. Anthropogenic tritium in the Loire River estuary, France

    NASA Astrophysics Data System (ADS)

    Péron, O.; Gégout, C.; Reeves, B.; Rousseau, G.; Montavon, G.; Landesman, C.

    2016-12-01

    This work is carried out in the frame of a radioecological monitoring of anthropogenic tritium from upstream and downstream of several nuclear power plants along the Loire River to its estuary. This paper studies the variation of anthropogenic tritium species in the Loire River system from upstream to the mouth of the estuary. Tritiated water (HTO and HTO in sediment pore water) and organically bound tritium (OBT) forms were analysed after dedicated pre-treatments. The collected environmental samples consist in (i) surface-sediment and core samples from the river floor, (ii) surface and water column samples. A maximum 3H activity concentration of 26 ± 3 Bq·L- 1 in the Loire River estuary is obtained whereas an environmental background level around 1 Bq·L- 1 is determined for a non influenced continental area by anthropogenic activities. The European follow-up indicator used as a screening value is 100 Bq·L- 1. The conservative tritium behaviour was used in order to characterize the tidal regime and river flow influences in the mixing zone of the Loire River estuary. Furthermore, OBT levels and total organically carbon (TOC) content are explored. Finally, ratios of OBT relative to HTO in sediment pore water in surface-sediment and core samples are also discussed.

  4. Man's Impact on the Environment: The Estuary as an Ecosystem.

    ERIC Educational Resources Information Center

    Brevard County School Board, Cocoa, FL.

    This environmental education guide focuses on man's impact on the estuary. The program contained in the guide is developed around the following nine questions: (1) What is a definition of the ecosystem being investigated?; (2) What are some of the biotic and abiotic features of the ecosystem and how do these features interrelate?; (3) Where are…

  5. Sources and Loading of Nitrogen to U.S. Estuaries

    EPA Science Inventory

    Previous assessments of land-based nitrogen loading and sources to U.S. estuaries have been limited to estimates for larger systems with watersheds at the scale of 8-digit HUCs and larger, in part due to the coarse resolution of available data, including estuarine watershed bound...

  6. Environmental features and macrofauna of Kahana Estuary, Oahu, Hawaii

    USGS Publications Warehouse

    Maciolek, J.A.; Timbol, A.S.

    1981-01-01

    Lack of ecological information on Hawaiian estuaries prompted an intensive 2-year study of a small (5.7 ha) stream-mouth estuary on windward Oahu. Water quality and macrofauna were sampled weekly at seven stations. The water mass was strongly stratified vertically except during freshets. Average values for water column temperature and bottom salinity were 23.2°C and 12‰ at the head to 28.3°C and 28‰ at the mouth. Dissolved oxygen saturation in the water column varied from about 50% at night to 140% in the afternoon. Usually, bottom waters were 3–6°C warmer than surface waters and sometimes showed severe oxygen depletion.Macrofauna, collected primarily by seining, consisted mainly of decapod crustaceans (four species of crabs, seven species of shrimps) and fishes (24 species). Other typical estuarine taxons (mollusks, barnacles, polychaetes) were scarce or absent. Diversity increased seaward from 14 species near the estuary head to 29 species near the mouth. Three species of crustaceans and six of fishes were captured at all stations. Most abundant were the native prawn, Macrobrachium grandimanus, and mullet, Mugil cephalus. Perennially resident adults occurred among crustaceans and gobioid fishes; most other fishes were present as juveniles and sporadic adults. Comparisons with other data suggest that more than 50 species of native fishes may occur in Hawaiian estuaries, and that estuarine macrofaunal diversity on oceanic islands is much lower than on continents at similar latitudes.

  7. BENTHIC NUTRIENT FLUX IN A SMALL ESTUARY IN NORTHWESTERNFLORIDA (USA)

    EPA Science Inventory

    Benthic Nutrient Flux in a Small Estuary in Northwestern Florida(USA).Gulf and Caribbean Research 18, 15-25, 2006.

    Benthic nutrient fluxes of ammonium (NH4+), nitrite/nitrate (NO2-+NO3-), phosphate (PO4-), and dissolved silica (DSi) were measured in Escambia Bay, an estuar...

  8. ECOLOGICAL CONDITION OF ESTUARIES IN THE GULF OF MEXICO

    EPA Science Inventory

    The Gulf of Mexico is a vast natural resource that encompasses the coastal areas of western Florida, Alabama, Mississippi, Louisiana and Texas, as well as a portion of Mexico. Many estuaries flow into the Gulf of Mexico and serve as nursery grounds for fish, habitat for a wide va...

  9. Estuary Entrance, Umpqua River, Oregon: Hydraulic Model Investigation.

    DTIC Science & Technology

    The Umpqua River estuary model was of the fixed-bed type, constructed to scales of 1:30 horizontally and 1:100 vertically, and reproduced the lower...28 miles of the Umpqua River and an adjoining portion of the Pacific Ocean. The model was equipped with the necessary appurtenances for accurate

  10. APPENDIX C - ADDITIONAL INFORMATION ON FLUSHING IN ESTUARIES

    EPA Science Inventory

    Water residence time is an important determinant of the sensitivity of the response of estuaries and other water bodies to nutrient loading. A variety of terms such as residence time, flushing time, transit time, turnover time, and age are used to describe time scales for transpo...

  11. Time scales in Galveston Bay: An unsteady estuary

    NASA Astrophysics Data System (ADS)

    Rayson, Matthew D.; Gross, Edward S.; Hetland, Robert D.; Fringer, Oliver B.

    2016-04-01

    Estuarine time scales including the turnover, particle e-folding time, the age (calculated with a passive tracer), and residence time (calculated with Lagrangian particles) were computed using a three-dimensional hydrodynamic model of Galveston Bay, a low-flow, partially stratified estuary. Time scales were computed during a time period when river flow varied by several orders of magnitude and all time scales therefore exhibited significant temporal variability because of the unsteadiness of the system. The spatial distributions of age and residence time were qualitatively similar and increased from 15 days in a shipping channel to >45 days in the upper estuary. Volume-averaged age and residence time decreased during high-flow conditions. Bulk time scales, including the freshwater and salinity turnover times, were far more variable due to the changing river discharge and salt flux through the estuary mouth. A criterion for calculating a suitable averaging time is discussed to satisfy a steady state assumption and to estimate a more representative bulk time scale. When scaled with a freshwater advective time, all time scales were approximately equal to the advective time scale during high-flow conditions and many times higher during low-flow conditions. The mean age, Lagrangian residence, and flushing times exhibited a relationship that was weakly dependent on the freshwater advective time scale demonstrating predictability even in an unsteady, realistic estuary.

  12. LATITUDINAL GRADIENTS IN BENTHIC COMMUNITY COMPOSITION IN WESTERN ATLANTIC ESTUARIES

    EPA Science Inventory

    The community structure of benthic macroinvertebrates from estuaries along the Atlantic coast of North America from Cape Cod, MA, to Biscayne Bay, FL, were compared. Benthic data were collected over a 5 year period (1990 to 1995) by the U.S. Environmental Protection Agency's Envi...

  13. The chemical control of soluble phosphorus in the Amazon estuary

    NASA Technical Reports Server (NTRS)

    Fox, L. E.; Wofsy, S. C.; Sager, S. L.

    1986-01-01

    The role of sediments in controlling concentrations of soluble phosphorous in the Amazon estuary is examined. The efflux of phosphorous through the estuary is calculated using data collected on field excursions in December 1982 and May 1983, and laboratory mixing experiments. It is observed that soluble phosphorus was released from bottom sediments at a rate of 0.2 micro-M/day, when in seawater and deionizd water mixtures. The relation between release rates and salinity and sediment concentrations is studied. A one-dimensional dispersion model was developed to estimate phosphate inputs to the estuary. The model predicted total fluxes of soluble inorganic phosphorous of 15 x 10 to the 6th mole/day for December 1982 and 27 x 10 to the 6th mole/day for May 1983; the predictions correlate with field observations. It is noted that phosphorous removal is between 0 and 4 ppt at a rate of 0.044 + or - 0.01 micron-M/ppt per day and the annual mean input of phophorous from Amazon to outer-estuary is 23 x 10 to the 6th moles/day.

  14. Invasion by stages in the St Louis River estuary

    EPA Science Inventory

    The St. Louis River estuary is recognized as an invasive species “hotspot” - the harbor ranks among the top locations in the Great Lakes reporting the first occurrence of new, aquatic non-native species. To date, 18 non-native benthic invertebrate, 4 non-native crusta...

  15. Approaches for Development of Nutrient Criteria in Oregon Estuaries

    EPA Science Inventory

    Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

  16. Reference Condition Approach for Numeric Nutrient Criteria for Oregon Estuaries

    EPA Science Inventory

    Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

  17. Phenology of larval fish in the St. Louis River estuary

    EPA Science Inventory

    Little work has been done on the phenology of fish larvae in Great Lakes coastal wetlands. As part of an aquatic invasive species early detection study, we conducted larval fish surveys in the St. Louis River estuary (SLRE) in 2012 and 2013. Using multiple gears in a spatially ba...

  18. ASSESSING THE ECOLOGICAL CONDITION OF VERACRUZ, MX ESTUARIES

    EPA Science Inventory

    As part of an international technology transfer activity between EPA's Office of Research and Development and the state of Veracruz's Sub-secretary of the Environment, 50 stations within estuaries along the gulf coast of the state of Veracruz MX, were sampled during June and July...

  19. SUSCEPTIBILITY OF A NORTHEASTERN GULF OF MEXICO ESTUARY TO HYPOXIA

    EPA Science Inventory

    Bottom water hypoxia is a common adverse consequence of nutrient enrichment in estuaries and coastal waters. To protect against hypoxia, it is helpful to know which waters are most susceptible to hypoxia. Hypoxia has been observed regularly in Pensacola Bay, a northeastern Gulf o...

  20. ANIMAL-HABITAT ASSOCIATIONS IN PACIFIC NORTHWEST ESTUARIES

    EPA Science Inventory

    The mission of the Pacific Coastal Ecology Branch (EPA, Newport, OR) is to determine the effects of habitat alteration by stressors on ecological resources in Pacific Northwest (PNW) estuaries. Research being conducted in support of this mission includes identifying critical hab...

  1. ECOLOGICAL CONDITION OF THE ESTUARIES OF OREGON AND WASHINGTON

    EPA Science Inventory

    Estuaries are bodies of water that receive freshwater and sediment from rivers and saltwater from the oceans. They are transition zones between the fresh water of a river and the salty environment of the sea. This interaction produces a unique environment that supports wildlife...

  2. Correspondence between zooplankton assemblages and the Estuary Environment Classification system

    NASA Astrophysics Data System (ADS)

    Lucena-Moya, Paloma; Duggan, Ian C.

    2017-01-01

    We tested whether variability in zooplankton assemblages was consistent with the categories of estuarine environments proposed by the 'Estuary Environment Classification' system (EEC) (Hume et al., 2007) across a variety of North Island, New Zealand, estuaries. The EEC classifies estuaries in to eight categories (A to F) based primarily on a combination of three abiotic controlling factors: ocean forcing, river forcing and basin morphometry. Additionally, we tested whether Remane's curve, which predicts higher diversities of benthic macrofauna and high and low salinities, can be applied to zooplankton assemblages. We focused on three of the eight EEC categories (B, D and F), which covered the range of estuaries with river inputs dominating (B) to ocean influence dominating (F). Additionally, we included samples from river (FW) and sea (MW) to encompass the entire salinity range. Zooplankton assemblages varied across the categories examined in accordance with a salinity gradient predicted by the EEC. Three groups of zooplankton were distinguishable: the first formed by the most freshwater categories, FW and B, and dominated by rotifers (primarily Bdelloidea) and estuarine copepods (Gladioferans pectinatus), a second group formed by categories D and F, of intermediate salinity, dominated by copepods (Euterpina acutifrons), and a final group including the purely marine category MW and dominated also by E. acutifrons along with other marine taxa. Zooplankton diversity responded to the salinity gradient in a manner expected from Remane's curve. The results of this study support others which have shown salinity to be the main factor driving zooplankton community composition and diversity.

  3. Estuaries May Face Increased Parasitism as Sea Levels Rise

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-12-01

    Invertebrates in estuaries could be at a greater risk of parasitism as climate change causes sea levels to rise. A new paper published 8 December in Proceedings of the National Academy of Sciences of the United States of America (doi:10.1073/pnas.1416747111) describes how rapid sea level rise in the Holocene affected the population of parasitic flatworms called trematodes.

  4. Larval fish distribution in the St. Louis River estuary

    EPA Science Inventory

    Our objective was to determine what study design, environmental, and habitat variables contribute to the distribution and abundance of larval fish in the St. Louis River estuary. Larval fish habitat associations are poorly understood in Great Lakes coastal wetlands, yet critical ...

  5. Aircraft towing feasibility study. Final report

    SciTech Connect

    Not Available

    1980-09-01

    Energy costs and availability are major concerns in most parts of the world. Many ways of increasing energy supply and reducing consumption are being proposed and investigated. One that holds considerable promise is the extended towing of aircraft between airport runways and terminal gate areas with engines shut down. This study provides a preliminary assessment of the constraints on and feasibility of extended aircraft towing. Past aircraft towing experience and the state-of-the-art in towing equipment are reviewed. Safety and operational concerns associated with aircraft towing are identified, and the benefits and costs of implementing aircraft towing at 20 major US airports are analyzed. It was concluded that extended aircraft towing is technically feasible and that substantial reductions in aircraft fuel consumption and air pollutant emissions can be achieved through its implementation. It was also concluded that, although capital and operating costs associated with towing would be increased, net savings could generally be attained at these airports. Because of the lack of past experience and the necessity of proving the cost effectiveness of the towing concept, a demonstration of the feasibility of large-scale aircraft towing is necessary. The study evaluates the suitability of the 20 study airports as potential demonstration sites and makes recommendations for the first demonstration project.

  6. Underground Engineering (Selected Articles),

    DTIC Science & Technology

    1984-04-30

    Examination of the Strength of Injected Concrete , by Peng Jizhong ............................................. Repair and Reinforcement of Cracks and...OF INJECTED CONCRETE Peng Jizhong Concrete injection is an advanced, economically feasible, and effective new technology. It is widely used both here...injecting concrete , which is the major construction -.cem for the third engineering section of the bureau, however, there is still a significant discrep

  7. Mathematical Model of Estuarial Sediment Transport.

    DTIC Science & Technology

    1977-10-01

    NUMBERS» Contract No. ^Ar DACW39-75-C-0080 ^^ 9. PERFORMING ORGANIZATION NAME AND ADDRESS Department of Civil Engineering...The original model, SEDIMENT I, was verified by comparison with measurements in a recirculating flume. The modified model, SEDIMENT II, developed for... organic matter from contiguous drainage areas, and waste materials. Clay minerals are hydrated aluminum silicates in a layer lattice crystal

  8. Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, Annual Report 2009

    SciTech Connect

    Diefenderfer, Heida L.; Johnson, Gary E.; Sather, Nichole K.; Skalski, John R.; Dawley, Earl M.; Coleman, Andre M.

    2010-08-01

    This report describes the 2009 research conducted under the U.S. Army Corps of Engineers (USACE or Corps) project EST-09-P-01, titled “Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary.” The research was conducted by the Pacific Northwest National Laboratory, Marine Science Laboratory and Hydrology Group, in partnership with the University of Washington, School of Aquatic and Fishery Sciences, Columbia Basin Research, and Earl Dawley (NOAA Fisheries, retired). This Columbia River Fish Mitigation Program project, referred to as “Salmonid Benefits,” was started in FY 2009 to evaluate the state-of-the science regarding the ability to quantify the benefits to listed salmonids1 of habitat restoration actions in the lower Columbia River and estuary.

  9. Holocene estuary development in the Algarve Region (Southern Portugal)

    NASA Astrophysics Data System (ADS)

    Schneider, Heike; Höfer, Dana; Trog, Carmen; Hempel, Rita; Daut, Gerhard; Mäusbacher, Roland

    2010-05-01

    Former coastal estuaries in the Algarve region of South Portugal are used for reconstruction coastal evolution since first marine transgression processes at about 8.000 years before. The sediments of these archives allow high resolution analyses of geochemical and palynological signals. Drillings in different lagoons of the Algarve region contain the sequences from the fluvial sediments during the early Holocene, marine transgression facies during the middle Holocene and the marine/fluvial sediment deposits until present. The results of the sedimentological, geochemical and palynological analyses show that each estuary developed differently, depending on the morphology of the paleovalley, environmental conditions and especially the influence of the sea and the formation of barrier systems. The estuaries were flooded between 7500 and 5500 cal a BP by sea level rise and were almost completely filled by sediment by the beginning of the Roman occupation (226 y BC / 2176 cal a BP). A clear change in sedimentological processes is evident in the estuaries between 5500 and 3000 cal a BP and is interpreted as a result of high energy events such as storms or tsunamis (Schneider et al. 2009, Hilbich et al. 2008 ). Palynological as well as archaeological investigations show distinct anthropogenic influences since 3500 cal. BP by increasing values in maquies, cereals and open land communities. References Hilbich, C., Mügler, I., Daut, G., Frenzel, P., van der Borg, K., Mäusbacher, R. (2008): Reconstruction of the depositional history of the former coastal lagoon of Vilamoura (Algarve, Portugal): A sedimentological, microfaunal and geophysical approach.- Journal of Coastal Research 24(2B), 83-91. Schneider, H., Höfer, D., Trog, C., Busch, S., Schneider, M., Baade, J., Daut, G. & R. Mäusbacher (2009): Holocene estuary development in the Algarve Region (Southern Portugal) - A reconstruction of sedimentological and ecological evolution. - Quaternary International (In Press

  10. Columbia River Estuary Ecosystem Classification — Concept and application

    USGS Publications Warehouse

    Simenstad, Charles A.; Burke, Jennifer L.; O'Connor, Jim E.; Cannon, Charles; Heatwole, Danelle W.; Ramirez, Mary F.; Waite, Ian R.; Counihan, Timothy D.; Jones, Krista L.

    2011-01-01

    This document describes the concept, organization, and application of a hierarchical ecosystem classification that integrates saline and tidal freshwater reaches of estuaries in order to characterize the ecosystems of large flood plain rivers that are strongly influenced by riverine and estuarine hydrology. We illustrate the classification by applying it to the Columbia River estuary (Oregon-Washington, USA), a system that extends about 233 river kilometers (rkm) inland from the Pacific Ocean. More than three-quarters of this length is tidal freshwater. The Columbia River Estuary Ecosystem Classification ("Classification") is based on six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. We define and map Levels 1-3 for the entire Columbia River estuary with existing geospatial datasets, and provide examples of Levels 4-6 for one hydrogeomorphic reach. In particular, three levels of the Classification capture the scales and categories of ecosystem structure and processes that are most tractable to estuarine research, monitoring, and management. These three levels are the (1) eight hydrogeomorphic reaches that embody the formative geologic and tectonic processes that created the existing estuarine landscape and encompass the influence of the resulting physiography on interactions between fluvial and tidal hydrology and geomorphology across 230 kilometers (km) of estuary, (2) more than 15 ecosystem complexes composed of broad landforms created predominantly by geologic processes during the Holocene, and (3) more than 25 geomorphic catenae embedded within ecosystem complexes that represent distinct geomorphic landforms, structures, ecosystems, and habitats, and components of the estuarine landscape most likely to change over short time periods.

  11. Nitrogen and phosphorus budgets of the Changjiang River estuary

    NASA Astrophysics Data System (ADS)

    Li, Xiang'an; Yu, Zhiming; Song, Xiuxian; Cao, Xihua; Yuan, Yongquan

    2011-07-01

    Eutrophication has emerged as a key environmental problem in Chinese coastal waters, especially in the Changjiang (Yangtze) River estuary. In this area, large nutrient inputs result in frequent harmful algal blooms and serious hypoxia in bottom waters. Four cruises were made in the estuary in 2006 to assess the concentration and distribution of dissolved inorganic nitrogen (DIN) and phosphorus (DIP). The concentration of DIN decreased gradually in a linear relationship with salinity from the river mouth to outer waters, while DIP was relatively more dispersed. A modified box budget method was used to estimate nutrient fluxes in the estuary and its adjacent waters. Water and nutrient budgets as well as primary production and denitrification rates were estimated from the box budget model. Estimated water residence time in the estuary was about 11 d. The turbid mixing zone released 33% of DIN and 49% of DIP, while in the adjacent outer sea 17.9 mmol DIN/m2·d and 0.36 mmol DIP/m2·d were fixed. Dissolved inorganic phosphorus was imported from the deep open sea waters, supporting primary production and population growth in this zone. Net ecosystem production (NEP) was calculated at 38.2 mmol/m2·d in the outer estuary and the estimated rate (N-fixation minus denitrification) was negative (1.92 mmol/m2·d), implying that a large amount of input nitrogen was taken up by algae and recycled through denitrification in bottom water and sediment.

  12. Salinity and turbidity distributions in the Brisbane River estuary, Australia

    NASA Astrophysics Data System (ADS)

    Yu, Yingying; Zhang, Hong; Lemckert, Charles

    2014-11-01

    The Brisbane River estuary (BRE) in Australia not only plays a vital role in ecosystem health, but is also of importance for people who live nearby. Comprehensive investigations, both in the short- and long-term, into the salinity and turbidity distributions in the BRE were conducted. Firstly, the analysis of numerical results revealed that the longitudinal salinity varied at approximately 0.45 and 0.61 psu/h during neap and spring tides, respectively. The turbidity stayed at a higher level and was less impacted by tide in the upper estuary, however, the water cleared up while the tide changed from flood to ebb in the mid and lower estuary. The second investigation into the seasonal variations of salinity and turbidity in the BRE was conducted, using ten-year field measurement data. A fourth-order polynomial equation was proposed, describing the longitudinal variation in salinity dilution changes as the upstream distance in the BRE during the wet and dry seasons. From the observation, the mid and upper estuaries were vertically well-mixed during both seasons, but the lower BRE was stratified, particularly during the wet season. The estuary turbidity maximum (ETM) zone was about 10 km longer during the wet season than the dry season. Particular emphasis was given to the third investigation into the use of satellite remote sensing techniques for estimation of the turbidity level in the BRE. A linear relationship between satellite observed water reflectance and surface turbidity level in the BRE was validated with an R2 of 0.75. The application of satellite-observed water reflectance therefore provided a practical solution for estimating surface turbidity levels of estuarine rivers not only under normal weather conditions, but also during flood events. The results acquired from this study are valuable for further hydrological research in the BRE and particularly prominent for immediate assessment of flood impacts.

  13. Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

    PubMed Central

    Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

    2016-01-01

    Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12–15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

  14. Assessment of trophic status in Changjiang (Yangtze) River estuary

    NASA Astrophysics Data System (ADS)

    Wang, Baodong

    2007-07-01

    The integrated methodology for the assessment of estuarine trophic status (ASSETS), which was extended and refined from the United States National Estuarine Eutrophication Assessment (NEEA), is a multi-parameter assessment system and has been widely used in eutrophication assessment in estuarine and coastal waters. The ASSETS was applied to evaluate the trophic status of the Changjiang (Yangtze) River estuary, one of the largest estuaries in the world. The following main results were obtained: (i) The estuarine export potential is “moderate susceptibility” due to the “moderate” dilution potential and “moderate” flushing potential; (ii) The overall human influence (OHI) index classified the impact of nutrients in the system as “high” due to the high level of nutrient discharge by the river which channels anthropogenic impacts in the catchments to the estuarine system; (iii) The overall eutrophic condition (OEC) in the estuary was classified into the “high” category due to frequent occurrence of nuisance and toxic algal blooms in the mixing and seawater zones; (iv) Since the nutrient loadings (e.g., DIN) in the river is expected to continue to increase in the near future following the population increase and rapid economic growth throughout the drainage basin, the nutrient-related symptoms in the estuary are likely to substantially worsen, which leads to the “worsen high” category for the definition of future outlook (DFO). The combinations of the three components (i.e., OHI, OEC, and DFO) lead to an overall grade as “bad” for the trophic status in the Changjiang River estuary.

  15. Thallium dynamics in the Weser estuary (NW Germany)

    NASA Astrophysics Data System (ADS)

    Böning, Philipp; Ehlert, Claudia; Niggemann, Jutta; Schnetger, Bernhard; Pahnke, Katharina

    2017-03-01

    Despite its toxicity and versatile geochemistry, not much is known on the distribution, speciation and behaviour of Thallium (Tl) in the marine coastal environment, notably in estuaries. We here contribute to the discussion by presenting dissolved (<0.45 μm) and particulate data of Tl, Fe, Mn, as well as dissolved organic carbon (DOC) and dissolved Si for two transects through the Weser estuary during summer (July 2013) and winter (early March 2014). The results show that both, dissolved Tl (70-130 pM) and DOC (100-1000 μM) are elevated against average river concentrations, show the same distinct seasonality, decrease with increasing salinity and positively deviate from conservative mixing. Compared to that, dissolved Si displays almost conservative mixing with seawater while dissolved Fe and Mn are quickly removed in the estuarine turbidity maximum (ETM) classically located in the low salinity region of the estuary. The data further suggest that both, dissolved Tl and DOC exhibit only little loss at the ETM, and that Tl does not seem to cycle with Fe and Mn as was suggested for other estuaries. Moreover, reactive particulate Tl (as calculated from excess Tl enriched versus the lithogenic background) on the particles amount to only 20-50% of the dissolved Tl concentrations. This is in agreement with earlier studies underlining the low particle reactivity of Tl. However, the strong correlation between dissolved Tl and DOC is new and suggests a combined cycling through the estuary. Albeit being indirect, our observations support earlier suggestions of a possible association of Tl with organic ligands, and that Tl tends to remain in the dissolved phase when entering the ocean.

  16. Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary.

    PubMed

    Lin, Xianbiao; Hou, Lijun; Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

    2016-01-01

    Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg(-1) d(-1) in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 10(5) t N yr(-1), and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12-15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication.

  17. Micro electric propulsion feasibility

    NASA Technical Reports Server (NTRS)

    Aston, Graeme; Aston, Martha

    1992-01-01

    , minimal detectability and low cost are requirements. All these miniature spacecraft share a common characteristic: because of their on-board electronic equipment they have, by design, solar order 50-100 W. In a relative sense, such spacecraft are power rich when compared to other larger spacecraft. This power rich situation is offset by very tight mass budgets, which make reductions in propellant mass requirements a key issue in meeting overall spacecraft minimum mass goals. In principle, power rich and propellant poor brilliant pebbles class spacecraft can benefit from using high specific impulse electric propulsion to reduce chemical propellant mass requirements. However, at power levels of order 50 W, arcjets cannot be made to function, ion thrusters are too complex and heavy and resistojets have too low a specific impulse. Recognizing these capability limitations in existing electric propulsion technology, the SDIO/IST sponsored the Phase I SBIR Micro Electric Propulsion (MEP) thruster study described in this report. The objective of this study was to examine the feasibility of developing a very simple, low mass and small volume, electric thruster for operation on hydrazine at less than 100 W of input power. The feasibility of developing such a MEP thruster was successfully demonstrated by EPL by the discovery of a novel plasma acceleration process. The sections in this report summarize the approach, test results and major accomplishments of this proof-of-concept program.

  18. Micro electric propulsion feasibility

    NASA Astrophysics Data System (ADS)

    Aston, Graeme; Aston, Martha

    1992-11-01

    , minimal detectability and low cost are requirements. All these miniature spacecraft share a common characteristic: because of their on-board electronic equipment they have, by design, solar order 50-100 W. In a relative sense, such spacecraft are power rich when compared to other larger spacecraft. This power rich situation is offset by very tight mass budgets, which make reductions in propellant mass requirements a key issue in meeting overall spacecraft minimum mass goals. In principle, power rich and propellant poor brilliant pebbles class spacecraft can benefit from using high specific impulse electric propulsion to reduce chemical propellant mass requirements. However, at power levels of order 50 W, arcjets cannot be made to function, ion thrusters are too complex and heavy and resistojets have too low a specific impulse. Recognizing these capability limitations in existing electric propulsion technology, the SDIO/IST sponsored the Phase I SBIR Micro Electric Propulsion (MEP) thruster study described in this report. feasibility of developing a very simple, low mass and small volume, electric thruster for operation on hydrazine at less than 100 W of input power. &The feasibility of developing such a MEP thruster was successfully demonstrated by EPL by the discovery of a novel plasma acceleration process. The sections in this report summarize the approach, test results and major accomplishments of this proof-of-concept program.

  19. Waste oyster shell as a kind of active filler to treat the combined wastewater at an estuary.

    PubMed

    Luo, Hongbing; Huang, Gu; Fu, Xiaoying; Liu, Xiaoling; Zheng, Daocai; Peng, Jian; Zhang, Ke; Huang, Bo; Fan, Liangqian; Chen, Fenghui; Sun, Xiubo

    2013-10-01

    Estuaries have been described as one of the most difficult environments on Earth. It is difficult to know how to treat the combined wastewater in tidal rivers at the estuary, where the situation is very different from ordinary fresh water rivers. Waste oyster shell was used as the active filler in this study in a bio-contact oxidation tank to treat the combined wastewater at the Fengtang Tidal River. With a middle-experimental scale of 360 m3/day, the average removal efficiency of COD, BOD, NH3-N, TP and TSS was 80.05%, 85.02%, 86.59%, 50.58% and 85.32%, respectively, in this bio-contact oxidation process. The living microbes in the biofilms on the waste oyster shell in this bio-contact oxidation tank, which were mainly composed of zoogloea, protozoa and micro-metazoa species, revealed that waste oyster shell as the filler was suitable material for combined wastewater degradation. This treatment method using waste oyster shell as active filler was then applied in a mangrove demonstration area for water quality improvement near the experiment area, with a treatment volume of 5 x 10(3) m3/day. Another project was also successfully applied in a constructed wetland, with a wastewater treatment volume of 1 x 10(3) m3/day. This technology is therefore feasible and can easily be applied on a larger scale.

  20. Seasonal dynamics of meiofauna in a South African temporarily open/closed estuary (Mdloti Estuary, Indian Ocean)

    NASA Astrophysics Data System (ADS)

    Nozais, Christian; Perissinotto, Renzo; Tita, Guglielmo

    2005-01-01

    One hundred and eighty-four of the 250 estuaries in South Africa are currently classified as temporarily open/closed and close off from the sea during the dry season, under low river inflow. The subtropical Mdloti Estuary, on the KwaZulu-Natal north coast, is one of these systems and hardly any information is available on its meiofauna. The abundance, biomass, composition, and grazing impact of meiofauna, as well as the key environmental factors that affect these variables, were investigated with emphasis on the contrast between open and closed phases of the estuary. Microphytobenthic chlorophyll a concentrations varied between 1.4 to 480 mg m -2. Meiofauna were composed of nematodes, harpacticoid copepods, crustacean nauplii, mites, turbellarians, polychaetes, oligochaetes, ostracods and chironomids. Total abundance of meiofauna showed large variability both spatially and temporally and ranged from 0.4 to 88×10 4 ind. m -2. Nematodes, mites and harpacticoid copepods occurred more often than other groups in the sediment. Total meiofauna carbon biomass exhibited similar temporal as well as spatial patterns as abundance and varied from 0.5 to 440 mg C m -2. A carbon-based grazing model, applied to the total meiofauna, provided estimates of potential daily ingestion rates ranging from 1.8 to 857 mg C m -2. Nematodes, mites and harpacticoid copepods contributed the most to the total potential daily ingestion rate of meiofauna in the Mdloti Estuary. Potential ingestion rates, determined using allometric equations, showed that meiofauna consumed from 0.1 to 254% of the microphytobenthic standing stock. Overall, meiofauna were likely not food limited and grazing on microphytobenthos was low, averaging 11% for the whole survey. A principal component analysis, applied to the whole study area and sampling period, indicated that major variations in meiofaunal community are mainly controlled by temperature and the state of the estuary's mouth (i.e. open/closed). Typically

  1. Building Regional Threat-Based Networks for Estuaries in the Western United States

    PubMed Central

    Merrifield, Matthew S.; Hines, Ellen; Liu, Xiaohang; Beck, Michael W.

    2011-01-01

    Estuaries are ecologically and economically valuable and have been highly degraded from both land and sea. Estuarine habitats in the coastal zone are under pressure from a range of human activities. In the United States and elsewhere, very few conservation plans focused on estuaries are regional in scope; fewer still address threats to estuary long term viability.We have compiled basic information about the spatial extent of threats to identify commonalities. To do this we classify estuaries into hierarchical networks that share similar threat characteristics using a spatial database (geodatabase) of threats to estuaries from land and sea in the western U.S.Our results show that very few estuaries in this region (16%) have no or minimal stresses from anthropogenic activity. Additionally, one quarter (25%) of all estuaries in this study have moderate levels of all threats. The small number of un-threatened estuaries is likely not representative of the ecological variability in the region and will require working to abate threats at others. We think the identification of these estuary groups can foster sharing best practices and coordination of conservation activities amongst estuaries in any geography. PMID:21387006

  2. Estuary Data Mapper: A Stand-Alone Tool for Geospatial Data Access, Visualization and Download for Estuaries and Coastal Watersheds of the United States

    EPA Science Inventory

    The US EPA Estuary Data Mapper (EDM; http://badger.epa.gov/rsig/edm/index.html) has been designed as a free stand-alone tool for geospatial data discovery, visualization, and data download for estuaries and their associated watersheds in the conterminous United States. EDM requi...

  3. Estuary Data Mapper: A Stand-Alone Tool for Geospatial Data Access, Visualization and Download for Estuaries and Coastal Watersheds of the United States. (UNH)

    EPA Science Inventory

    The US EPA Estuary Data Mapper (EDM; http://badger.epa.gov/rsig/edm/index.html) has been designed as a free stand-alone tool for geospatial data discovery, visualization, and data download for estuaries and their associated watersheds in the conterminous United States. EDM requi...

  4. Why Do Some Estuaries Close: A Model of Estuary Entrance Morphodynamics.

    NASA Astrophysics Data System (ADS)

    McSweeney, S. L.; Kennedy, D. M.; Rutherfurd, I.

    2014-12-01

    Intermittently Closed/Open Coastal Lakes/Lagoons (ICOLLs) are a form of wave-dominated, microtidal estuary that experience periodic closure in times of low river flow. ICOLL entrance morphodynamics are complex due to the interaction between wave, tidal and fluvial processes. Managers invest substantial funds to artificially open ICOLLs as they flood surrounding property and infrastructure, and have poor water quality. Existing studies examine broad scale processes but do not identify the main drivers of entrance condition. In this research, the changes in entrance geomorphology were surveyed before and after artificial entrance openings in three ICOLLs in Victoria, Australia. Changes in morphology were related to continuous measures of sediment volume, water level, tide and wave energy. A six-stage quantitative phase model of entrance geomorphology and hydrodynamics is presented to illustrate the spatio-temporal variability in ICOLL entrance morphodynamics. Phases include: breakout; channel expansion with rapid outflow; open with tidal exchange; initial berm rebuilding with tidal attenuation; partial berm recovery with rising water levels; closed with perched water levels. Entrance breakout initiates incision of a pilot channel to the ocean, whereby basin water levels then decline and channel expansion as the headcut migrates landwards. Peak outflow velocities of 5 m/s-3 were recorded and channel dimensions increased over 6 hrs to 3.5 m deep and 140 m wide. When tidal, a clear semi-diurnal signal is superimposed upon an otherwise stable water level. Deep-water wave energy was transferred 1.8 km upstream of the rivermouth with bores present in the basin. Berm rebuilding occurred by littoral drift and cross-shore transport once outflow ceased and microscale bedform features, particularly antidunes, contributed to sediment progradation. Phase duration is dependant on how high the estuary was perched above mean sea level, tidal prism extent, and onshore sediment supply

  5. Multnomah County Hydrokinetic Feasibility Study: Final Feasibility Study Report

    SciTech Connect

    Spain, Stephen

    2012-03-15

    HDR has completed a study of the technical, regulatory, and economic feasibility of installing hydrokinetic turbines under the Morrison, Broadway, and Sellwood bridges. The primary objective of installing hydrokinetic turbines is a demonstration of in-stream hydrokinetic technologies for public education and outreach. Due to the low gradient of the Lower Willamette and the effects of the tide, velocities in the area in consideration are simply not high enough to economically support a commercial installation. While the velocities in the river may at times provide enough energy for a commercial turbine to reach capacity, the frequency and duration of high flow events which provide suitable velocities is not sufficient to support a commercial hydrokinetic installation. We have observed that over an 11 year period, daily average velocities in the Lower Willamette exceeded a nominal cut-in speed of 0.75 m/s only 20% of the time, leaving net zero power production for the remaining 80% of days. The Sellwood Bridge site was estimated to have the best hydrokinetic resource, with an estimated average annual production of about 9,000 kWh. The estimated production could range from 2,500 kWh to 15,000 kWh. Based on these energy estimates, the amount of revenue generated through either a power purchase agreement (PPA) or recovered through net metering is not sufficient to repay the project costs within the life of the turbine. The hydrokinetic resource at the Morrison and Broadway Bridges is slightly smaller than at the Sellwood Bridge. While the Broadway and Morrison Bridges have existing infrastructure that could be utilized, the project is not expected to generate enough revenue to repay the investment. Despite low velocities and energy production, the sites themselves are favorable for installation of a demonstration or experimental project. With high public interest in renewable energy, the possibility exists to develop a hydrokinetic test site which could provide

  6. Modeling ecosystem processes with variable freshwater inflow to the Caloosahatchee River Estuary, southwest Florida. I. Model development

    NASA Astrophysics Data System (ADS)

    Buzzelli, Christopher; Doering, Peter H.; Wan, Yongshan; Sun, Detong; Fugate, David

    2014-12-01

    Variations in freshwater inflow have ecological consequences for estuaries ranging among eutrophication, flushing and transport, and high and low salinity impacts on biota. Predicting the potential effects of the magnitude and composition of inflow on estuaries over a range of spatial and temporal scales requires reliable mathematical models. The goal of this study was to develop and test a model of ecosystem processes with variable freshwater inflow to the sub-tropical Caloosahatchee River Estuary (CRE) in southwest Florida from 2002 to 2009. The modeling framework combined empirically derived inputs of freshwater and materials from the watershed, daily predictions of salinity, a box model for physical transport, and simulation models of biogeochemical and seagrass dynamics. The CRE was split into 3 segments to estimate advective and dispersive transport of water column constituents. Each segment contained a sub-model to simulate changes in the concentrations of organic nitrogen and phosphorus (ON and OP), ammonium (NH4+), nitrate-nitrite (NOx-), ortho-phosphate (PO4-3), phytoplankton chlorophyll a (CHL), and sediment microalgae (SM). The seaward segment also had sub-models for seagrasses (Halodule wrightii and Thalassia testudinum). The model provided realistic predictions of ON in the upper estuary during wet conditions since organic nitrogen is associated with freshwater inflow and low salinity. Although simulated CHL concentrations were variable, the model proved to be a reliable predictor in time and space. While predicted NOx- concentrations were proportional to freshwater inflow, NH4+ was less predictable due to the complexity of internal cycling during times of reduced freshwater inflow. Overall, the model provided a representation of seagrass biomass changes despite the absence of epiphytes, nutrient effects, or sophisticated translocation in the formulation. The model is being used to investigate the relative importance of colored dissolved organic

  7. Assessment on vulnerability of coastal wetlands to sea level rise in the Yangtze Estuary, China

    NASA Astrophysics Data System (ADS)

    Cui, L.; Ge, Z.; Zhang, L.

    2013-12-01

    The Yangtze Delta in China is vital economic hubs in terms of settlement, industry, agriculture, trade and tourism as well as of great environmental significance. In recent decades, the prospect of climate change, in particular sea level rise and its effects on low lying coastal areas have generated worldwide attention to coastal ecosystems. Coastal wetlands, as important parts of coastal ecosystem, are particularly sensitive to sea level rise. To study the responses of coastal wetlands to climate change, assess the impacts of climate change on coastal wetlands and formulate feasible and practical mitigation strategies are the important prerequisites for securing the coastal zone ecosystems. In this study, taking the coastal wetlands in the Yangtze Estuary as a case study, the potential impacts of sea-level rise to coastal wetlands habitat were analyzed by the Source-Pathway-Receptor-Consequence (SPRC) model. The key indicators, such as the sea-level rise rate, subsidence rate, elevation, daily inundation duration of habitat and sedimentation rate, were selected to build a vulnerability assessment system according to the IPCC definition of vulnerability, i.e. the aspects of exposure, sensitivity and adaptation. A quantitatively spatial assessment method on the GIS platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability. The vulnerability assessment on the coastal wetlands in the Yangtze Estuary under the sea level rise rate of the present trend and IPCC A1F1 scenario were performed for three sets of projections of short-term (2030s), mid-term (2050s) and long-term (2100s). The results showed that at the present trend of sea level rise rate of 0.26 cm/a, 92.3 % of the coastal wetlands in the Yangtze Estuary was in the EVI score of 0 in 2030s, i.e. the impact of sea level rise on habitats/species of coastal wetlands was negligible. While 7.4 % and 0.3 % of the coastal wetlands were in the EVI score of

  8. Feasibility of a simplified fuel additive evaluation protocol

    SciTech Connect

    Lister, S.J.; Hunzinger, R.D.; Taghizadeh, A.

    1998-12-31

    This report describes the work carried out during the four stages of the first phase of a project that involved the determination of the feasibility of replacing the Association of American Railroads Recommended Practice (ARRP) 503 protocol for testing diesel fuel oil additives with a new procedure using the single cylinder research engine SCRE-251 as the laboratory test engine, which tests for both engine performance as well as emissions compliance. The report begins with a review of the literature on fuel additive testing, then reviews the new US Environmental Protection Agency regulations regarding locomotive diesel emissions. This is followed by a review of the ARRP 503 protocol and the proposed new procedure, a comparison of the ARRP 503 test engines and the SCRE-251, and a study of the SCRE-251`s ability to represent a multi-cylinder medium-speed diesel engine. Appendices include fuel additive manufacturers` information sheets.

  9. Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program.

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2008-02-20

    The purpose of this document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program, hereafter called 'the Estuary Program'. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows: (1) Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. (2) Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. (3) Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. (4) Maintain the food web to benefit salmonid performance. (5) Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. The goal leads to three primary management questions pertaining to the main focus of the Estuary Program: estuary habitat conservation and restoration. (1) Are the estuary habitat actions achieving the expected biological and environmental performance targets? (2) Are the offsite habitat actions in the estuary improving juvenile salmonid performance and which actions are most effective at addressing the limiting factors preventing achievement of habitat, fish, or wildlife performance objectives? (3) What are the limiting factors or threats in the estuary/ocean preventing the achievement of desired habitat or fish performance objectives? Performance measures for the

  10. Engineering Encounters: Engineering Adaptations

    ERIC Educational Resources Information Center

    Gatling, Anne; Vaughn, Meredith Houle

    2015-01-01

    Engineering is not a subject that has historically been taught in elementary schools, but with the emphasis on engineering in the "Next Generation Science Standards," curricula are being developed to explicitly teach engineering content and design. However, many of the scientific investigations already conducted with students have…

  11. How hydrodynamics control algal blooms in the Ythan estuary, Scotland

    NASA Astrophysics Data System (ADS)

    Champangern, Khruewan; Hoey, Trevor; Thomas, Rhian

    2016-04-01

    The Ythan estuary, northeast Scotland, was designated in 2000 as a Nitrate Vulnerable Zone (NVZ) under the European Commission (EC) Nitrates Directive. Much of the catchment is intensively farmed and water quality has been adversely affected by nutrients from agricultural fertilizers. As a result, algal mats develop annually on tidal flats where sediment from upstream and from the adjacent dune systems is deposited. Understanding the patterns of water (river and ocean) circulation in the estuary as well as understanding how nutrients and sediments are transported in the estuary is crucial for understanding the role of several factors (elevation; sediment characteristics; nutrient flux) control the locations and scale of annual algal blooms. In order to understand those controls, study of interactions between hydrodynamic factors and water quality, in particular chlorophyll levels, at different time scales has been carried out. The results from the study reveal complex seasonal and event-scale relationships of river flow with the amount of chlorophyll, which provide an initial comprehension of controls over the concentrations of chlorophyll in the estuary. The concentration of chlorophyll changes, whether increasing or decreasing, with regards to changes in river flow. During high flow events, high amounts of chlorophyll are found when the tide is low. During low flow events, high amounts of chlorophyll are found at high tides. These phenomena reveal that both river flow and tidal cycle affect the amount of chlorophyll in the estuary. In addition, the Delft3d flow model, which has been extensively applied to many coastal and estuarine studies is used to simulate hydrodynamic patterns in the estuary during high flow and low flow events. The model is composed of 36,450 fine resolution grids and the upstream/ downstream boundary that represents water level is based on time-series data from river flow and tidal measurements. The bathymetry used for the model domain is

  12. Feasibility of Automated Adaptive GCA (Ground Controlled Approach) Controller Training System.

    ERIC Educational Resources Information Center

    Feuge, Robert L.; And Others

    An analysis of the conceptual feasibility of using automatic speech recognition and understanding technology in the design of an advanced training system was conducted. The analysis specifically explored application to Ground Controlled Approach (GCA) controller training. A systems engineering approach was followed to determine the feasibility of…

  13. 77 FR 42489 - Notice of Availability of the Draft Feasibility Study; Environmental Impact Statement for the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-19

    ... Department of the Army; Corps of Engineers Notice of Availability of the Draft Feasibility Study... has prepared a Draft Feasibility Report/Environmental Impact Statement (FR/EIS) for the Chatfield Reservoir Storage Reallocation Study, Littleton, Colorado and by this notice is announcing the extension...

  14. WERF MACT Feasibility Study Report

    SciTech Connect

    B. Bonnema; D. Moser; J. Riedesel; K. Kooda; K. Liekhus; K. Rebish; S. Poling

    1998-11-01

    This study was undertaken to determine the technical feasibility of upgrading the Waste Experimental Reduction Facility (WERF) at the Idaho National Engineering and Environmental Laboratory to meet the offgas emission limits proposed in the Maximum Achievable Control Technologies (MACT)rule. Four practicable offgas treatment processes were identified, which, if installed, would enable the WERF to meet the anticipated MACT emission limits for dioxins and furans (D/F), hydrochloric acid (HCI), and mercury (Hg). Due to the three-year time restraint for MACT compliance, any technology chosen for the upgrade must be performed within the general plant project funding limit of $5 M. The option selected consists of a partial-quench evaporative cooler with dry sorbent injection for HCI removal followed by a sulfur-impregnated activated carbon bed for Hg control. The planning cost estimate for implementing the option is $4.17 M (with 24% contingency). The total estimated cost includes capital costs, design and construction costs, and project management costs. Capital costs include the purchase of a new offgas evaporative cooler, a dry sorbent injection system with reagent storage, a new fabric filter baghouse, a fixed carbon bed absorber, and two offgas induced draft exhaust fans. It is estimated that 21 months will be required to complete the recommended modification to the WERF. The partial-quench cooler is designed to rapidly cool the offgas exiting the secondary combustion chamber to minimize D/F formation. Dry sorbent injection of an alkali reagent into the offgas is recommended. The alkali reacts with the HCI to form a salt, which is captured with the fly ash in the baghouse. A design HCI removal efficiency of 97.2% allows for the feeding 20 lbs/hr of chlorine to the WERF incinerator. The sorbent feed rate can be adjusted to achieve the desired HCI removal efficiency. A fixed bed of sulfur-impregnated carbon was conservatively sized for a total Hg removal capacity when

  15. Functional diversity of fish communities in two tropical estuaries subjected to anthropogenic disturbance.

    PubMed

    Dolbeth, M; Vendel, A L; Pessanha, A; Patrício, J

    2016-11-15

    The functional diversity of fish communities was studied along the salinity gradient of two estuaries in Northeast Brazil subjected to different anthropogenic pressures, to gain a better understanding of the response of fish communities to disturbance. We evaluated functional complementarity indices, redundancy and analysed functional composition through functional groups based on combinations of different traits. The fish communities in both estuaries share similar functions performed by few functional groups. The upstream areas had generally lower taxonomic, functional diversity and lower redundancy, suggesting greater vulnerability to impacts caused by human activities. Biomass was slightly more evenly distributed among functional groups in the less disturbed estuary, but total biomass and redundancy were lower in comparison to the urbanized estuary. The present findings lend strength to the notion that the less disturbed estuary may be more susceptible to anthropogenic impacts, underscoring the need for more effective conservation measures directed at this estuary.

  16. A Multi-disciplinary Study of Frontal Systems in the Tay Estuary, Scotland

    NASA Astrophysics Data System (ADS)

    Ferrier, G.; Anderson, J. M.

    1997-09-01

    The results of a remote sensing study of tidal mixing processes in the Tay Estuary have been correlated with the results of mathematical and physical models and ground sampling data in an attempt to assess the nature, the spatial and temporal extent and the variability in the formation of convergent fronts in the Tay Estuary. The application of remote sensing methods to the study of estuarine mixing processes in the Tay Estuary, supported by ground measurements, has discovered convergent front mechanisms and complex hydrodynamic processes which had not previously been recognized in the Tay Estuary. This integrated approach has enabled the various features and mixing mechanisms found in the lower section of the estuary to be interrelated. The limitations of using a two-dimensional mathematical and a physical model to predict the complex mixing processes affecting water quality in the Tay Estuary are discussed.

  17. Plastic pollution in five urban estuaries of KwaZulu-Natal, South Africa.

    PubMed

    Naidoo, Trishan; Glassom, David; Smit, Albertus J

    2015-12-15

    Monitoring plastic concentrations in estuaries is vital in assessing the magnitude of terrestrial inputs to oceanic environments. Data on plastics ≤ 5 mm in estuaries are scant. This study determined microplastic levels within five estuaries along the Durban coastline and on intervening beaches. Plastics were isolated from estuarine sediment, beach sediment and the surface water of each estuary and characterised. Sediment at the Bayhead area of Durban harbour had the highest average plastic concentrations (745.4 ± 129.7 particles per 500 ml) and an attenuating concentration trend away from the city centre was found. Prevailing south to north longshore drift was hypothesised to result in plastic accumulation on the northern shores of beaches with estuarine effluents, however, this was not found. Fragments composed the largest percent of plastics (59%) found in Bayhead, whereas fibres dominated other estuaries with proportions ranging from 38% of total plastics in the uMgeni estuary to 66% in the Mdloti.

  18. Contemporary distribution of macrozoobenthic communities of the Yeisk estuary (Taganrog Bay of the Sea of Azov)

    NASA Astrophysics Data System (ADS)

    Nabozhenko, M. V.; Kovalenko, E. P.

    2011-08-01

    The contemporary distribution of macrozoobenthic communities of the Yeisk estuary is considered. Four basic types of communities are classified. Communities with domination of Tubificidae (Oligochaeta) occupy the greatest part of the estuary. Communities with domination of Amphipoda (Corophiidae) remained only in the northeast part of the reservoir. The unstable hydrological conditions and the absence of clearly expressed horohalinicum lead to mixing of Ponto-Caspian and Azov-Black Sea faunas in the Yeisk estuary.

  19. Linking behavior, physiology, and survival of Atlantic Salmon smolts during estuary migration

    USGS Publications Warehouse

    Stich, Daniel S.; Zydlewski, Gayle B.; Kocik, John F.; Zydlewski, Joseph

    2015-01-01

    Decreased marine survival is identified as a component driver of continued declines of Atlantic Salmon Salmo salar. However, estimates of marine mortality often incorporate loss incurred during estuary migration that may be mechanistically distinct from factors affecting marine mortality. We examined movements and survival of 941 smolts (141 wild and 800 hatchery-reared fish) released in freshwater during passage through the Penobscot River estuary, Maine, from 2005 to 2013. We related trends in estuary arrival date, movement rate, and survival to fish characteristics, migratory history, and environmental conditions in the estuary. Fish that experienced the warmest thermal history arrived in the estuary 8 d earlier than those experiencing the coolest thermal history during development. Estuary arrival date was 10 d later for fish experiencing high flow than for fish experiencing low flow. Fish released furthest upstream arrived in the estuary 3 d later than those stocked further downstream but moved 0.5 km/h faster through the estuary. Temporally, movement rate and survival in the estuary both peaked in mid-May. Spatially, movement rate and survival both decreased from freshwater to the ocean. Wild smolts arrived in the estuary later than hatchery fish, but we observed no change in movement rate or survival attributable to rearing history. Fish with the highest gill Na+, K+-ATPase activity incurred 25% lower mortality through the estuary than fish with the lowest gill Na+, K+-ATPase activity. Smolt survival decreased (by up to 40%) with the increasing number of dams passed (ranging from two to nine) during freshwater migration. These results underscore the importance of physiological preparedness on performance and the delayed, indirect effects of dams on survival of Atlantic Salmon smolts during estuary migration, ultimately affecting marine survival estimates.

  20. Chemical and physical characteristics of water in estuaries of Texas; October 1978-September 1983

    USGS Publications Warehouse

    Fisher, J.C.; Grozier, R.U.

    1985-01-01

    Streamfl ow-measuring sites are used to monitor both the amount and quality of water that enter the estuarine embayments. The farthest downstream sites available are located many miles upstream from the estuaries because of the effect of changes in water stage in the estuaries. Consequently, there is inflow into the bays below these sites that can and do affect the amount and quality of water entering the estuaries.

  1. Multi-Scale Action Effectiveness Research in the Lower Columbia River and Estuary, 2011

    DTIC Science & Technology

    2012-05-01

    from fundamental ecology toward the effectiveness of restoration in the Lower Columbia River and estuary (LCRE). The research is conducted within the...evaluate the effectiveness of habitat restoration projects in the lower river and estuary at site- and landscape-scales. This annual report covers...freshwater research project shifted from fundamental ecology toward the effectiveness of restoration in the Lower Columbia River and estuary (LCRE

  2. Subtidal sea level variability in a shallow Mississippi River deltaic estuary, Louisiana

    USGS Publications Warehouse

    Snedden, G.A.; Cable, J.E.; Wiseman, W.J.

    2007-01-01

    The relative roles of river, atmospheric, and tidal forcings on estuarine sea level variability are examined in Breton Sound, a shallow (0.7 m) deltaic estuary situated in an interdistributary basin on the Mississippi River deltaic plain. The deltaic landscape contains vegetated marshes, tidal flats, circuitous channels, and other features that frictionally dissipate waves propagating through the system. Direct forcing by local wind stress over the surface of the estuary is minimal, owing to the lack of significant fetch due to landscape features of the estuary. Atmospheric forcing occurs almost entirely through remote forcing, where alongshore winds facilitate estuary-shelf exchange through coastal Ekman convergence. The highly frictional nature of the deltaic landscape causes the estuary to act as a low-pass filter to remote atmospheric forcing, where high-frequency, coastally-induced fluctuations are significantly damped, and the damping increases with distance from the estuary mouth. During spring, when substantial quantities of controlled Mississippi River inputs (q?? = 62 m3 s-1) are discharged into the estuary, upper estuary subtidal sea levels are forced by a combination of river and remote atmospheric forcings, while river effects are less clear downestuary. During autumn (q?? = 7 m3 s-1) sea level variability throughout the estuary is governed entirely by coastal variations at the marine boundary. A frequency-dependent analytical model, previously used to describe sea level dynamics forced by local wind stress and coastal forcing in deeper, less frictional systems, is applied in the shallow Breton Sound estuary. In contrast to deeper systems where coastally-induced fluctuations exhibit little or no frictional attenuation inside the estuary, these fluctuations in the shallow Breton Sound estuary show strong frequency-dependent amplitude reductions that extend well into the subtidal frequency spectrum. ?? 2007 Estuarine Research Federation.

  3. Physical, hydrological, and biological characteristics of the Loxahatchee River estuary, Florida

    USGS Publications Warehouse

    McPherson, Benjamin F.; Sabanskas, Maryann; Long, William Atwood

    1982-01-01

    The Loxahatchee River estuary in southeast Florida has periodically closed and opened to the sea as a result of natural causes. In the last 30 years, the estuary has remained open only by dredging. Activities of man in the estuary and basin affect freshwater and tidal flow which in turn affect bathymetry, bottom sediment, and biota. Under present conditions, tidal flow is much larger than freshwater inflow. (USGS)

  4. Environmental Impact Research Program: Selection of Turbulence and Mixing Parameterizations for Estuary Water Quality Models.

    DTIC Science & Technology

    1985-08-01

    interaction of freshwater and saltwater as a criterion for estuarine description, and quotes Cameron and Pritchard (1963), who state that "An estuary...consideration of the saltwater /freshwater mixing scenarios within the estuary. Consideration of these saltwater effects may be implicit, such as the...motion at the mouth causes the entire estuary to oscillate, and through the forces of viscous dissipation, the saltwater mixes upward, as in the salt

  5. Metals in the sediments along the Hudson River estuary

    SciTech Connect

    Gibbs, R.J. )

    1994-01-01

    The distribution of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in bottom and suspended sediments from the ocean up the Hudson River estuary for 70 km were analyzed. The bottom sediments has a metal concentration maximum in the harbor. Everywhere studied, the metal concentrations in suspension are much higher than in the bottom sediments by 30 times for Cd, 20 times for Cu, and 10 to 15 times for Co, Cr, Ni, Pb, and Zn. The composition of metals in the suspended material varied along the estuary with a large metal maximum in the harbor and again in Haverstraw Bay. By standardizing toxic metal concentrations to Fe, a maximum level of pollution in New York Harbor is indicated, along with a lesser maximum in Haverstraw Bay.

  6. Study of red tide prediction model for the Changjiang Estuary

    NASA Astrophysics Data System (ADS)

    Wang, Zheng-Fang; Lu, Hai-Yan; Zhang, Qing; Lu, Yong; Zeng, Jiang-Ning; Zhou, Qing-Song

    2000-12-01

    This paper based on field data (on red tide water quality monitoring at the Chaggjiang River mouth and Hutoudu mariculture area in Zhejiang Province from May to August in 1995, and May to September in 1996) presents an effective model for short term prediction of red tide in the Changjiang Estuary. The measured parameters include: depth, temperature, color diaphaneity, density, DO, COD and nutrients (PO4-P, NO2-N, NO3-N, NH4-N). The model was checked by field-test data, and compared with other related models. The model: Z=SAL-3.95 DO-2.974 PH-5.421 PO4-P is suitable for application to the Shengsi aquiculture area near the Changjiang Estuary.

  7. Chlorofluorocarbons in the Hudson estuary during summer months

    SciTech Connect

    Clark, J.F.; Smethie, W.M. Jr.; Simpson, H.J.

    1995-10-01

    Chlorofluorocarbon (CFC) concentrations in the Hudson estuary were found to be greater than the atmospheric solubility equilibrium concentration, demonstrating that the entire reach is contaminated with CFCs from local wastewater discharge. Samples have been collected along the axis of the lower Hudson estuary over a 5-month period to assess temporal and spatial variability of their wastewater sources. The highest CFC concentrations were found in water collected near Manhattan. In this region, CFC-11 (CCl{sub 3}F) and CFC-12 (CCl{sub 2}F{sub 2}) were 3 to 5 and 10 to 20 times saturation, respectively. There appears to be a continuous CFC source in the New York City area, although the magnitude of this source declined during summer months. Other large CFC source were found near Albany, and in Haverstraw Bay (60 km north of Manhattan). 29 refs., 6 figs., 3 tabs.

  8. Multibiomarker assessment of three Brazilian estuaries using oysters as bioindicators

    SciTech Connect

    Valdez Domingos, F.X. Azevedo, M.; Silva, M.D.; Randi, M.A.F.; Freire, C.A.; Silva de Assis, H.C.; Oliveira Ribeiro, C.A.

    2007-11-15

    Oysters have been largely employed as bioindicators of environmental quality in biomonitoring studies. Crassostrea rhizophorae was selected to evaluate the health status of three estuarine areas impacted by anthropogenic activities along the Brazilian coast, in three estuarine complexes, ranging in latitude from 7 to 25 deg. S. In each estuary three sites were sampled in Winter and in Summer: a site considered as reference, and two sites next to contamination sources. Condition index was similar at all sites and estuaries, with the highest values found for Itamaraca oysters in Summer. Necrosis, hyperplasia, mucocyte hypertrophy and fusion of ordinary filaments were the main histopathological lesions observed. Muscle cholinesterase activity was overall similar, but with a strong seasonal effect. Inhibition or activation of branchial total ATPase and Na,K-ATPase activities at the contaminated sites was observed. The health status of these estuarine areas is quite similar, and the combined use of biomarkers is recommended.

  9. Chlorofluorocarbons in the Hudson Estuary During Summer Months

    NASA Astrophysics Data System (ADS)

    Clark, Jordan F.; Smethie, William M.; Simpson, H. James

    1995-10-01

    Chlorofluorocarbon (CFC) concentrations in the Hudson estuary were found to be greater than the atmospheric solubility equilibrium concentration, demonstrating that the entire reach is contaminated with CFCs from local wastewater discharge. Samples have been collected along the axis of the lower Hudson estuary over a 5-month period to assess temporal and spatial variability of their wastewater sources. The highest CFC concentrations were found in water collected near Manhattan. In this region, CFC-11 (CCl3F) and CFC-12 (CCl2F2) were 3 to 5 and 10 to 20 times saturation, respectively. There appears to be a continuous CFC source in the New York City area, although the magnitude of this source declined during summer months. Other large CFC sources were found near Albany, and in Haverstraw Bay (60 km north of Manhattan).

  10. Modeling centuries of estuarine morphodynamics in the Western Scheldt estuary

    NASA Astrophysics Data System (ADS)

    Dam, G.; Wegen, M.; Labeur, R. J.; Roelvink, D.

    2016-04-01

    We hindcast a 110 year period (1860-1970) of morphodynamic behavior of the Western Scheldt estuary by means of a 2-D, high-resolution, process-based model and compare results to a historically unique bathymetric data set. Initially, the model skill decreases for a few decades. Against common perception, the model skill increases after that to become excellent after 110 years. We attribute this to the self-organization of the morphological system which is reproduced correctly by the numerical model. On time scales exceeding decades, the interaction between the major tidal forcing and the confinement of the estuary overrules other uncertainties. Both measured and modeled bathymetries reflect a trend of decreasing energy dissipation, less morphodynamic activity, and thus a more stable morphology over time, albeit that the estuarine adaptation time is long (approximately centuries). Process-based models applied in confined environments and under constant forcing conditions may perform well especially on long (greater than decades) time scales.

  11. Nutrient cycling and plant dynamics in estuaries: A brief review

    NASA Astrophysics Data System (ADS)

    Flindt, Mogens R.; Pardal, Miguel Ângelo; Lillebø, Ana Isabel; Martins, Irene; Marques, João Carlos

    1999-07-01

    Eutrophication of European estuaries due to massive nutrient loading from urban areas and diffuse runoff from extensively cultivated land areas is analysed. Consequences for the ecology of estuaries, namely changes in plant species composition, which also affects heterotrophic organisms, are approached based on examples showing that the result is often a fundamental structural change of the ecosystem, from a grazing and/or nutrient controlled stable systems to unstable detritus/mineralisation systems, where the turnover of oxygen and nutrients is much more dynamic and oscillations between aerobic and anaerobic states frequently occur. Several relevant aspects are examined, namely the influence of rooted macrophytes on nutrient dynamics, by comparing bare bottom sediments with eelgrass covered sediments, primary production and the development of organic detritus, and hydrodynamics and its relations to the spatial distribution of macrophytes in estuarine systems.

  12. Effects of Prevailing Winds on Turbidity of a Shallow Estuary

    PubMed Central

    Cho, Hyun Jung

    2007-01-01

    Estuarine waters are generally more turbid than lakes or marine waters due to greater algal mass and continual re-suspension of sediments. The varying effects of diurnal and seasonal prevailing winds on the turbidity condition of a wind-dominated estuary were investigated by spatial and statistical analyses of wind direction, water level, turbidity, chlorophyll a, and PAR (Photosynthetically Active Radiation) collected in Lake Pontchartrain, Louisiana, USA. The prolonged prevailing winds were responsible for the long-term, large-scale turbidity pattern of the estuary, whereas the short-term changes in wind direction had differential effects on turbidity and water level in varying locations. There were temporal and spatial changes in the relationship between vertical light attenuation coefficient (Kd) and turbidity, which indicate difference in phytoplankton and color also affect Kd. This study demonstrates that the effect of wind on turbidity and water level on different shores can be identified through system-specific analyses of turbidity patterns. PMID:17617683

  13. Effects of environmental stress on the condition of Littorina littorea along the Scheldt estuary (The Netherlands).

    PubMed

    Van den Broeck, Heidi; De Wolf, Hans; Backeljau, Thierry; Blust, Ronny

    2007-04-15

    The condition of the periwinkle Littorina littorea, expressed in terms of its shell morphology, reproductive impairment (i.e. female sterility/intersex, male penis shedding), trematode infestation load, lipid reserves and dry/wet weight ratio, was determined in function of environmental stress along the polluted Western and relatively clean Eastern Scheldt estuary (The Netherlands). The upstream increasing pollution and decreasing salinity levels along the Western Scheldt estuary (Fig. 1) are reflected in the dry/wet weight ratio and lipid content of the periwinkles. Compared to the Eastern Scheldt, female intersex (i.e. indicator of TBT pollution) and sterility occurred more frequently in the Western Scheldt estuary, while male penis shedding was even restricted to the latter estuary. The highest population intersex and sterility incidence was found near the harbour of Vlissingen and reflects potential nautical activities. The number of trematode infested periwinkles did not differ between both estuaries, although local sampling site differences were detected within each estuary, reflecting the complex interactions that exist among parasites, hosts and the local environment. Finally, both estuaries were maximally discriminated from each other based on the shell weight of the periwinkles using a canonical discriminant analysis. Periwinkles with the heaviest shells were found in the Western Scheldt estuary and may reflect growth rate or structural population differences caused by the less favourable living conditions in the Western Scheldt estuary.

  14. Circulation and physical processes within the San Gabriel River Estuary during summer 2005

    USGS Publications Warehouse

    Rosenberger, Kurt J.; Xu, Jingping; Stein, Eric D.; Noble, Marlene A.; Gartner, Anne L.

    2007-01-01

    The Southern California Coastal Water Research Project (SCCWRP) is developing a hydrodynamic model of the SGR estuary, which is part of the comprehensive water-quality model of the SGR estuary and watershed investigated by SCCWRP and other local agencies. The hydrodynamic model will help understanding of 1) the exchange processes between the estuary and coastal ocean; 2) the circulation patterns in the estuary; 3) upstream natural runoff and the cooling discharge from PGS. Like all models, the SGR hydrodynamic model is only useful after it is fully calibrated and validated. In May 2005, SCCWRP requested the assistance of the U.S. geological Survey (USGS) Coastal and Marine Geology team (CMG) in collecting data on the hydrodynamic conditions in the estuary during the summer dry season. The summer was chosen for field data collection as this was assumed to be the season with the greatest potential for chronic degraded water quality due to low river flow and high thermal stratification within the estuary (due to both higher average air temperature and PGS output). Water quality can be degraded in winter as well, when higher river discharge events bring large volumes of water from the Los Angeles basin into the estuary. The objectives of this project were to 1) collect hydrodynamic data along the SGR estuary; 2) study exchange processes within the estuary through analysis of the hydrodynamic data; and 3) provide field data for model calibration and validation. As the data only exist for the summer season, the results herein only apply to summer conditions.

  15. Phosphorus fractionation distribution in Guapimirim estuary: SE Brazil.

    PubMed

    Vicente, Michel Arthur Faria; de Melo, Gustavo Vaz; Baptista Neto, José Antonio; de Oliveira, Allan Sandes

    2016-01-01

    The Guapimirim estuary is the main tributary of Guanabara bay and is located in the northeast portion. Although it is protected, this estuary has been experiencing strong anthropogenic pressure, which has led to changes in the natural characteristics. Large amounts of sewage are dumped into the bay through tributaries, thereby changing the water and bottom sediment quality. One of the main elements of sewage is phosphorus. Despite its importance to life, a high concentration of this nutrient in the environment can result in eutrophication. This work describes the phosphorus distribution in its different fractions in the bottom sediment at 16 stations located in the main channel of the Guapimirim estuary. These results are correlated with data on grain size, organic matter and calcium carbonate content in the bottom sediment and with physicochemical parameters of the bottom water. The grain size decreases toward the mouth of the estuary, whereas the organic matter and carbonate content increase. The salinity increases significantly at 3.5 km upstream from the mouth, where there is also a notable increase in fine sediments; the same site is the mean position of the salinity front. The temperature and pH increase in the same direction. The Pinorg-total ranges between 3.18 and 7.13 µmol g(-1), increasing toward the mouth. The same trend is observed for the other phosphorus fractions P-Ca, P-Fe and P-f.a., which range from 0.68 to 1.91, 0.79 to 1.71 and 0.03 to 0.93 µmol g(-1), respectively. The P-Ca and P-Fe fractions are the most representative in the Pinorg-total, occurring at 26.3 and 26.0 %, respectively.

  16. Effects of wave forcing on a subterranean estuary

    NASA Astrophysics Data System (ADS)

    Xin, Pei; Robinson, Clare; Li, Ling; Barry, D. A.; Bakhtyar, R.

    2010-12-01

    Wave and tide are important forcing factors that typically coexist in coastal environments. A numerical study was conducted to investigate individual and combined effects of these forces on flow and mixing processes in a nearshore subterranean estuary. A hydrodynamic model based on the shallow water equations was used to simulate dynamic sea level oscillations driven by wave and tide. The oscillating sea levels determined the seaward boundary condition of the coastal aquifer, where variably saturated, variable density flow was modeled. The simulation results showed that waves induced an onshore upward tilt in the phase-averaged sea level (wave setup). The resulting hydraulic gradient generated pore water circulations in the nearshore zone of the coastal aquifer, which led to formation of an upper saline plume (USP) similar to that formed due to tides. However, mixing of recirculating seawater in the USP with underlying fresh groundwater was less intensive under the high-frequency wave oscillations. In the case of combined forcing, wave-induced circulations coupled with the intratidal flows strengthened the averaged, circulating pore water flows in the nearshore zone over the tidal period. The circulating flows increased exchange between the subterranean estuary and ocean, contributing 61% of the total submarine groundwater discharge for the simulated condition in comparison with the 40% and 49% proportions caused by the same but separate tidal and wave forcing, respectively. The combined forces also created a more extensive USP with the freshwater discharge zone shifted farther seaward. The freshwater flow paths in the intertidal subterranean estuary were modified with a significant increase in the associated transit times. The interplay of wave and tide led to increased mixing between discharging fresh groundwater and recirculating seawater. These results further demonstrate the complexity of nearshore groundwater systems and have implications for future

  17. Bedforms and Evolution of Tropical Estuaries: Examples from Northeastern Brazil

    NASA Astrophysics Data System (ADS)

    Vital, H.; Soares, C.; Rocha, G.; Pereira, T.; Eichler, P.

    2012-12-01

    This paper intends to show the geomorphological and sedimentary responses of tropical estuaries to meteorological and oceanographic forcing. The study area is located on the coastal zone of Rio Grande do Norte State, northeastern Brazil. This coast is under natural influence of waves and tides with a semidiurnal mesotidal regime and anthropogenic influence (urbanization, oil and salt industries, shrimp farms, and tourism). An operational methodology was developed using collection and analysis of an integrated dataset (comprising remote sensing, oceanographic, hy-droacoustic, and sedimentologic data). All data were integrated through a geographical infor-mation system database. The imaging of subaqueous features allowed the identification of differ-ent bedforms as well as submerged rocky outcrops. Four main groups of bedforms were identi-fied: 2D and 3D large dunes, ripples and flat bottom, and rocky outcrops as well. Rocky outcrops were correlated to Barreiras Formation and beachrocks. The estuarine channel is filled by Holocene sandy- to silt sediments, with sandy sediments in the main channel ranging from well-selected to selected grains, and silty sediments in the river margins. The integration and analysis of currents velocity and other physical parameters with bedforms characterization and different sedimentary textures in the study area allows a better knowledge of the active sedimentary processes, which are responsible for the formation of morphologic features of these estuaries. The evolution of estuary settings, led by the postglacial sea-level rise, is recorded in the subsurface an present-day riverbed. These results contribute to a better understanding of tropical estuaries.; Location of the study area

  18. Sedimentary framework of the Potomac River estuary, Maryland

    USGS Publications Warehouse

    Knebel, Harley J.; Martin, E. Ann; Glenn, J.L.; Needell, Sally W.

    1981-01-01

    Analyses of seismic-reflection profiles, sediment cores, grab samples, and side-scan sonar records, along with previously collected borehole data, reveal the characteristics, distribution, and geologic history of the shallow strata beneath the Potomac River estuary. The lowermost strata are sediments of the Chesapeake Group (lower Miocene to lower Pleistocene) that crop out on land near the shore but are buried as much as 40 m below the floor of the estuary. The top of these sediments is an erosional unconformity that outlines the Wisconsinan valley of the Potomac River. This valley has a sinuous trend, a flat bottom, a relief of 15 to 34 m, and axial depths of 34 to 54 m below present sea level. During the Holocene transgression of sea level, the ancestral valley was filled with as much as 40 m of sandy and silty, fluvial-to-shallow estuarine sediments. The fill became the substrate for oyster bars in the upper reach and now forms most marginal slopes of the estuary. Since sea level approached its present position (2,000 to 3,000 yr ago), the main channel has become the locus of deposition for watery, gray to black clay or silty clay, and waves and currents have eroded the heterogeneous Quaternary sediments along the margins, leaving winnowed brown sand on shallow shoreline flats. Pb-210 analyses indicate that modern mud is accumulating at rates ranging from 0.16 to 1.80 cm/yr, being lowest near the mouth and increasing toward the head of the estuary. This trend reflects an increased accumulation of fine-grained fluvial sediments near the turbidity maximum, similar to that found in nearby Chesapeake Bay. The present annual accumulation of mud is about 1.54 million metric tons; the cumulative mass is 406 million metric tons.

  19. Environmental public health surveillance: possible estuary-associated syndrome.

    PubMed

    Backer, L C; Niskar, A S; Rubin, C; Blindauer, K; Christianson, D; Naeher, L; Rogers, H S

    2001-10-01

    Public health surveillance involves the collection, analysis, and dissemination of data for use in public health practice. A surveillance system includes the capacity to collect and analyze data as well as the ability to disseminate the data to public health agencies that can undertake effective prevention and control activities. An emerging issue in environmental public health surveillance involves human exposure to the toxins produced by microorganisms present in oceans and estuaries. One of these organisms is Pfiesteria piscicida Steidinger & Burkholder, a dinoflagellate found in estuaries along the Atlantic and gulf coasts of the United States. There have been reports of both human illness associated with occupational exposures to concentrated laboratory cultures of P. piscicida and massive fill kills associated with the presence of the organism in rivers and estuaries. These reports, and anecdotal reports from people who worked on rivers where the organism has been found, generated concern that environmental exposures to P. piscicida, similar organisms, or perhaps a toxin or toxins produced by the organism(s), could cause adverse human health effects. To begin to evaluate the public health burden associated with P. piscicida, investigators from the National Center for Environmental Health at Centers for Disease Control and Prevention and health agencies from states along the Atlantic coast collaborated to develop a passive surveillance system for collecting, classifying, and tracking public inquiries about the organism. Specifically, the group developed exposure and symptom criteria and developed data collection and reporting capabilities to capture the human health parameters collectively referred to as possible estuary-associated syndrome (PEAS). The surveillance system was implemented in six states (Delaware, Florida, Maryland, North Carolina, South Carolina, Virginia) beginning in June 1998. From 1 June 1998 through 30 June 2001, the six state health

  20. Environmental public health surveillance: possible estuary-associated syndrome.

    PubMed Central

    Backer, L C; Niskar, A S; Rubin, C; Blindauer, K; Christianson, D; Naeher, L; Rogers, H S

    2001-01-01

    Public health surveillance involves the collection, analysis, and dissemination of data for use in public health practice. A surveillance system includes the capacity to collect and analyze data as well as the ability to disseminate the data to public health agencies that can undertake effective prevention and control activities. An emerging issue in environmental public health surveillance involves human exposure to the toxins produced by microorganisms present in oceans and estuaries. One of these organisms is Pfiesteria piscicida Steidinger & Burkholder, a dinoflagellate found in estuaries along the Atlantic and gulf coasts of the United States. There have been reports of both human illness associated with occupational exposures to concentrated laboratory cultures of P. piscicida and massive fill kills associated with the presence of the organism in rivers and estuaries. These reports, and anecdotal reports from people who worked on rivers where the organism has been found, generated concern that environmental exposures to P. piscicida, similar organisms, or perhaps a toxin or toxins produced by the organism(s), could cause adverse human health effects. To begin to evaluate the public health burden associated with P. piscicida, investigators from the National Center for Environmental Health at Centers for Disease Control and Prevention and health agencies from states along the Atlantic coast collaborated to develop a passive surveillance system for collecting, classifying, and tracking public inquiries about the organism. Specifically, the group developed exposure and symptom criteria and developed data collection and reporting capabilities to capture the human health parameters collectively referred to as possible estuary-associated syndrome (PEAS). The surveillance system was implemented in six states (Delaware, Florida, Maryland, North Carolina, South Carolina, Virginia) beginning in June 1998. From 1 June 1998 through 30 June 2001, the six state health

  1. Climate Change Will Affect Nutrient Dispersal In UK Estuaries

    NASA Astrophysics Data System (ADS)

    Bergamaschi, B. A.; Robins, P. E.; Cooper, D.

    2015-12-01

    It is still largely unclear how nutrients that travel through the catchment-river system are distributed within estuaries. How long will nutrients remain in the estuary, and what proportion will disperse offshore into the oceans? In the UK, where many catchments are relatively small and steep, estuaries react rapidly to rainfall events, which crucially control the mixing process, even though tidal stirring is generally large. Seasonal and short-term variability in estuarine functioning is therefore greater than variabilities over semi-diurnal timescales linked to tidal cycling. We present both published and on-going research that is emerging from an interdisciplinary pan-UK NERC Macronutrient Cycles Programme (macronutrient-cycles.ouce.ox.ac.uk). We pull together intensive field campaigns (Howlett et al. 2015) and model simulations (Robins et al. 2015), and present for the first time coupled simulations of catchment-river-estuary nutrient transport, using a variety of hydrological and hydrodynamic models. We investigate the response of the hydrodynamics and nutrients to extreme flows and storm surge events, and the response to climate change by simulating the IPCC 5th Assessment projections for 2100. On-going research will extend this integrated approach into the macronutrient controls on atmospheric-land exchange. Emerging research from our UK case study suggests that simulating the hourly river hydrograph, rather than daily-averaged, is important for estuarine response and recovery; daily-averaged flowrates, which are commonly used, under-predict the offshore transport of nutrients. Moreover, biogeochemical processing, whilst detected over estuarine residence times, did not measurably alter the estuarine concentrations, due to the much stronger advective fluxes. By simulating past mean and extreme events, using time-series analysis of river flow and tidal level data collected over the past 50 years, we are able to characterise the future estuarine nutrient

  2. Stirling Engine Heat Pump

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru

    Recent advances in the feasibility studies related to the Stirling engines and Stirling engine heat pumps which have been considered attractive due to their promising role in helping to solve the global environmental and energy problems,are reviewed. This article begins to describe the brief history of the Stirling engines and theoretical thermodynamic analysis of the Stirling cycle in order to understand several advantages on the Stirling engine. Furthermore,they could throw light on our question why the dream engines had not been promoted to practical applications during two hundred years. The present review shows that the Stirling engines with several unique advantages including 30 to 40% thermal efficiency and preferable exhaust characteristics,had been designed and constructed by recent tackling for the development of the advanced automobile and other applications using them. Based on the current state of art,it is being provided to push the Stirling engines combined with heat pumps based on the reversed Rankine cycle to the market. At present,however, many problems, especially for the durability, cost, and delicate engine parts must be enforced to solve. In addition,there are some possibilities which can increase the attractiveness of the Stirling engines and heat pumps. The review closes with suggestions for further research.

  3. Carbon dioxide emissions from estuaries of northern and northeastern Brazil.

    PubMed

    Noriega, Carlos; Araujo, Moacyr

    2014-08-22

    The carbon dioxide flux through the air-water interface of coastal estuarine systems must be quantified to understand the regional balance of carbon and its transport through adjacent coastal regions. We estimated and calculated the emissions of carbon dioxide (FCO₂) and the partial pressure of CO₂ (pCO₂) values in 28 estuarine environments at a variety of spatial scales in the northern and northeastern regions of Brazil. The results showed a mean FCO₂ (water to air) of 55 ± 45 mmol·m(-2)·d(-1). Additionally, a negative correlation between dissolved oxygen saturation and pCO₂ was observed, indicating a control by biological processes and especially by organic matter degradation. This leads to increased dissolved CO₂ concentration in estuarine waters which results in a pCO₂ that reached 8,638 μatm. Our study suggests that northern and northeastern Brazilian estuaries act as sources of atmospheric CO₂. The range of pCO₂ observed were similar to those found in inner estuaries in other places around the world, with the exception of a few semi-arid estuaries (Köppen climate classification - BSh) in which record low levels of pCO₂ have been detected.

  4. An ecohydrology model of the Guadiana Estuary (South Portugal)

    NASA Astrophysics Data System (ADS)

    Wolanski, Eric; Chicharo, Luís; Chicharo, M. Alexandra; Morais, Pedro

    2006-10-01

    A 1-D ecohydrology model is proposed that integrates physical, chemical and biological processes in the Guadiana Estuary during low flow conditions and that predicts the ecosystem health as determined by the following variables: river discharge, nutrients, suspended particulate matter, phytoplankton, zooplankton, bivalves, zooplanktivorous fish and carnivorous/omnivorous fish. Low flow conditions prevail now that the Alqueva dam has been constructed. The ecological sub-model is based on the non-linear Lotka-Volterra equation. The model is successful in capturing the observations of along-river changes in these variables. It suggests that both bottom-up and top-down ecological processes control the Guadiana Estuary ecosystem health. A number of sensitivity tests show that the model is robust and can be used to predict - within likely error bounds provided by the sensitivity tests - the consequences on the estuary ecosystem health of human activities throughout the river catchment, such as the irrigation farming downstream of the Alqueva dam, reclamation of the salt marshes by urban developments, and flow regulation by the Alqueva dam. The model suggests that the estuarine ecosystem health requires transient river floods and is compromised by flow regulation by the Alqueva dam. Remedial measures are thus necessary.

  5. Benchmarking an unstructured grid sediment model in an energetic estuary

    NASA Astrophysics Data System (ADS)

    Lopez, Jesse E.; Baptista, António M.

    2017-02-01

    A sediment model coupled to the hydrodynamic model SELFE is validated against a benchmark combining a set of idealized tests and an application to a field-data rich energetic estuary. After sensitivity studies, model results for the idealized tests largely agree with previously reported results from other models in addition to analytical, semi-analytical, or laboratory results. Results of suspended sediment in an open channel test with fixed bottom are sensitive to turbulence closure and treatment for hydrodynamic bottom boundary. Results for the migration of a trench are very sensitive to critical stress and erosion rate, but largely insensitive to turbulence closure. The model is able to qualitatively represent sediment dynamics associated with estuarine turbidity maxima in an idealized estuary. Applied to the Columbia River estuary, the model qualitatively captures sediment dynamics observed by fixed stations and shipborne profiles. Representation of the vertical structure of suspended sediment degrades when stratification is underpredicted. Across all tests, skill metrics of suspended sediments lag those of hydrodynamics even when qualitatively representing dynamics. The benchmark is fully documented in an openly available repository to encourage unambiguous comparisons against other models.

  6. Large wood in the Snowy River estuary, Australia

    NASA Astrophysics Data System (ADS)

    Hinwood, Jon B.; McLean, Errol J.

    2017-02-01

    In this paper we report on 8 years of data collection and interpretation of large wood in the Snowy River estuary in southeastern Australia, providing quantitative data on the amount, sources, transport, decay, and geomorphic actions. No prior census data for an estuary is known to the authors despite their environmental and economic importance and the significant differences between a fluvial channel and an estuarine channel. Southeastern Australian estuaries contain a significant quantity of large wood that is derived from many sources, including river flood flows, local bank erosion, and anthropogenic sources. Wind and tide are shown to be as important as river flow in transporting and stranding large wood. Tidal action facilitates trapping of large wood on intertidal bars and shoals; but channels are wider and generally deeper, so log jams are less likely than in rivers. Estuarine large wood contributes to localised scour and accretion and hence to the modification of estuarine habitat, but in the study area it did not have large-scale impacts on the hydraulic gradients nor the geomorphology.

  7. Environmental contaminants in bald eagles in the Columbia River estuary

    SciTech Connect

    Anthony, R.G.; Garrett, M.G. ); Schuler, C.A. )

    1993-01-01

    Eggs, blood, and carcasses of bald eagles (Haliaeetus leucocephalus) and fish were collected and breeding success of eagles was monitored in the Columbia River estuary, 1980-87, to determine if contaminants were having an effect on productivity. High levels of dichloro diphenyl dichloroethylene (DDE), polychlorinated biphenyls (PCB's), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were found in eggs, blood from adults, and 2 eagle carcasses. Detectable levels of DDE and PCB's were found in blood of nestlings indicating they were exposed to these contaminants early in life. Increasing concentrations of DDE and PCB's with age also indicated accumulation of these contaminants. Adult eagles also had higher levels of mercury (Hg) in blood than subadults or young indicating accumulation with age. The high levels of DDE and PCB's were associated with eggshell thinning ([bar x] = 10%) and with productivity ([bar x] = 0.56 young/occupied site) that was lower than that of healthy populations (i.e., [ge]1.00 young/occupied site). DDE and PCB's had a deleterious effect on reproduction of bald eagles in the estuary. The role dioxins play in eagle reproduction remains unclear, but concentrations in eagle eggs were similar to those in laboratory studies on other species where dioxins adversely affected hatchability of eggs. Probable source of these contaminants include dredged river sediments and hydroelectric dams, and the proper management of each may reduce the amount of contaminants released into the Columbia River estuary. 46 refs., 1 fig., 4 tabs.

  8. Salinity and suspended matter variations in the Tay estuary

    NASA Astrophysics Data System (ADS)

    McManus, John

    2005-03-01

    The concept of salinity-induced density layering in estuaries was first demonstrated from the upper reaches of the Tay. In this study the nature of the layering and its variation through the tidal cycle is demonstrated from time series of observations taken at many locations within this estuary. Thorough mixing of the waters on the rising tide, as defined by depth profiles of salinity, is commonly replaced by salinity layering during the high water slack period. This condition continues into the falling tide. Frequently the mixed waters are abruptly replaced by stratified waters within the half-hourly sampling interval. This is attributed to the activity of longitudinal fronts, manifest as surficial foam bands, along which water masses shear past each other on both the flood and ebb tides. Offsetting of transverse salinity coutours along the fronts is introduced to explain apparent complexities in surface water salinity distributions measured at high water slack. Suspended particulate matter concentrations increase towards the limit of the saline water intrusion before decreasing headwards into the freshwater zone of the estuary. The suspensions in the water column may also be displaced by the lateral offsetting of the waters along the fronts. The recognition of the presence of fronts, and a knowledge of their impact on the estuarine waters may provide an alternative means of understanding the flow characteristics of these challenging water bodies. The techniques of spatial and temporal averaging normally widely used today may not be the most realistic approach to analysis of the flows.

  9. Radiocaesium distribution in the sediment of a Fukushima river estuary

    NASA Astrophysics Data System (ADS)

    Hagiwara, Hiroki; Konishi, Hiromi; Nakanishi, Takahiro; Harada, Hisaya; Tsuruta, Tadahiko

    2016-04-01

    On fluvial discharge, paticulate fractions are the main carrier of radiocaesium from land to aquatic bodies such as rivers, lakes and the sea [1]. However, within river estuaries, where there is a drastic increase in salinity, fine particles generally flocculate (in the size order of several tens μm) before settling out and being deposited on the river bed [2]. In this study, we investigated the sediment records and the distribution of radiocaesium within the estuary of the Odaka river in January 2014, located approximately 17 km north of the Fukushima Dai-ichi Nuclear Power Plant. Based on distribution of salinity, the environment of the Odaka river is divided into three areas; the freshwater area, the estuarine marine area that was filled with saline water from surface to bottom and the brackish area between these two. Radiocaesium deposition ranged from 45 to 1070 kBq m-2 with the inventory of radiocaesium in the estuary being significantly greater in the brackish area relative to both the freshwater and estuarine marine areas. Particle size dependency of radiocaesium concentration in the sediments showed that the distribution with relatively higher concentration was expected in the brackish area. The possibility of flocculation in the brackish area will be discussed. References [1] Nagao, S., Kanamori, M., Ochiai, S., Tomihara, S., Fukushi, K., and Yamamoto, M., 2013, Biogeosciences, v. 10, no. 10, p. 6215-6223. [2] Droppo, I. G., and Ongley, E. D., 1994, Water Research, v. 28, no. 8, p. 1799-1809.

  10. Palaeoecology: a tool to improve the management of Australian estuaries.

    PubMed

    Saunders, Krystyna M; Taffs, Kathryn H

    2009-06-01

    Addressing environmental problems in estuaries is a worldwide problem. Establishing benchmarks and targets for management is critical, whether the aim is conservation, restoration or sustainable use. Palaeoecological techniques have rapidly improved during the past decade, particularly with advances in methods that allow high resolution quantitative assessments of environmental change. Palaeoecology is a useful tool in environmental management as it allows pre-impact conditions, the rate, extent, direction and cause of change, and range of natural variability to be determined. Australian estuarine ecosystems are qualitatively different from the often more well-studied estuaries in North America and Europe, which means site-specific studies of Australian estuaries are needed to inform management. While a potentially useful and valuable tool, palaeoecological techniques have not yet been widely adopted and practically implemented as part of estuarine management strategies and policy frameworks in Australia. We discuss the role palaeoecological techniques have to play in estuarine management by providing two case studies undertaken in Australia that have provided management information. We aim to encourage communication and dialogue between scientists and environmental managers about the potential for widespread practical adoption and implementation of palaeoecological techniques into Australian estuarine science, management and policy frameworks.

  11. Metal concentrations in sediments and clams in four Moroccan estuaries.

    PubMed

    Cheggour, M; Chafik, A; Fisher, N S; Benbrahim, S

    2005-03-01

    Metals (Cd, Cu, Ni, Zn, Mn and Fe) were analyzed seasonally over three years in sediments and in tissues of the clam Scrobicularia plana in four Moroccan Atlantic estuaries: Loukkos, Sebou, Bou Regreg and Oum er Rbia. Of these metals, Cd was at the lowest concentrations in sediment. Concentrations of Cu, Zn, and to a lesser extent Ni, in sediments suggest greater contamination in Sebou and Bou Regreg than in the other estuaries. The fluctuations of Mn and Fe concentrations in the fine surface sediments reflect their continental origin and show seasonal variations that indicate soil run-off following rain events. Concentrations of Cu, Zn, and especially Ni in clam tissues in these estuaries were generally higher than in some other common bioindicator bivalve species. The seasonal variations in S. plana's tissue metal concentrations are linked to patterns of reproductive activity for all metals except Cd and possibly Zn, whose tissue concentrations may be regulated. Mn and Fe concentrations in S. plana were positively correlated to sediment levels of these metals.

  12. Particulate metal distribution in Guadiana estuary punctuated by flood episodes

    NASA Astrophysics Data System (ADS)

    Caetano, Miguel; Vale, Carlos; Falcão, Manuela

    2006-10-01

    The distribution of major (Al, Ca, Mg, Fe and Mn) and trace metals (Zn, Cu, Pb and Cd) in particulate material was determined in different flow and tidal conditions along the Guadiana estuary. Under moderate river flows, concentrations of Al in SPM decreased seawards, while Ca and Mg showed an opposite trend reflecting the physical mixing of fluvial and marine particles along the salinity gradient. Ratios of Cu/Al, Zn/Al, Pb/Al and Cd/Al increased sharply in the estuary mouth as a result of local inputs of urban sewage from the two major cities located at the estuary mouth. Under these flow conditions Cu/Al and Cd/Al ratios were higher in spring, indicating that retention by phytoplankton was the major factor influencing these metal gradients in SPM. Sediments transported during an exceptional flood contained higher inorganic fraction and lower metal content (two orders of magnitude) than particles transported under moderate river flows. The material exported during flood peaks was recorded in the Guadiana shelf as coarser sediment layer with diminished levels of Fe, Cu and Pb. In spite of metal mobility in upper sediment layers of the coastal zone, these metals reflect the export episodes in Guadiana. The construction of Alqueva dam will attenuate in the future these flood events decreasing the amount of sediment supplied by the river to the coastal zone.

  13. Predicting habitat associations of five intertidal crab species among estuaries

    NASA Astrophysics Data System (ADS)

    Vermeiren, Peter; Sheaves, Marcus

    2014-08-01

    Intertidal crab assemblages that are active on the sediment surface of tropical estuaries during tidal exposure play an important role in many fundamental ecosystem processes. Consequently, they are critical contributors to a wide range of estuarine goods and services. However, a lack of understanding of their spatial organization within a large landscape context prevents the inclusion of intertidal crabs into generally applicable ecological models and management applications. We investigated spatial distribution patterns of intertidal crabs within and among eight dry tropical estuaries spread across a 160 km stretch of coast in North East Queensland, Australia. Habitat associations were modelled for five species based on photographic sampling in 40-80 sites per estuarine up- and downstream component: Uca seismella occurred in sites with little structure, bordered by low intertidal vegetation; Macrophthalmus japonicus occupied flat muddy sites with no structure or vegetation; Metopograpsus frontalis and Metopograpsus latifrons occupied sites covered with structure in more than 10% and 25% respectively. Finally, both Metopograpsus spp. and Metopograpsus thukuhar occupied rock walls. Habitat associations were predictable among estuaries with moderate to high sensitivity and low percentages of false positives indicating that simple, physical factors were adequate to explain the spatial distribution pattern of intertidal crabs. Results provide a necessary first step in developing generally applicable understanding of the fundamental mechanisms driving spatial niche organization of intertidal crabs within a landscape context.

  14. Trace metals in the Góta river estuary

    NASA Astrophysics Data System (ADS)

    Danielsson, Lars-Göran; Magnusson, Bertil; Westerlund, Stig; Zhang, Kerong

    1983-07-01

    The concentrations of the trace metals Cd, Cu, Fe, Ni, Pb and Zn in the Göta River estuary have been investigated. The following metal fractions have been determined: acid-leachable, dissolved, labile and particulate. The estuary represents a salt wedge type estuary and is situated in a densely populated region of Sweden. The metal concentrations found for the dissolved fraction is in the range of what can be considered as background levels for freshwater. It is difficult to evaluate any estuarine processes other than conservative mixing for Cd, Cu, Ni and Zn. The dissolved levels in the freshwater end member are Cd, 9-25 ngl -1; Cu, 1·1-1·4 μgl -1; Fe, 20-75 μg l -1: Ni, 0·7-0·9 μg l -1: Pb 0·09-0·2 μg l -1; and Zn, 6-7 μg l -1: The results from the acid-leachable fraction show that at high suspended load the particles sediment in the river mouth. The trace metal levels in this fraction are subject to large variations.

  15. An empirical model for estimating phytoplankton productivity in estuaries

    USGS Publications Warehouse

    Cole, B.E.; Cloern, J.E.

    1987-01-01

    e have previously shown that primary productivity in San Francisco Bay, USA, is highly correlated with phytoplankton biomass B (chlorophyll a concentration) and an index of light avallability in the photic zone, 2, I, (photic depth times surface irradiance). To test the generality of this relation, we compiled data from San Francisco Bay and 5 other USA estuarine systems (Neuse and South Rivers, Puget Sound, Delaware Bay and Hudson River Plume), and regressed daily produclvity J' P (mg C m-2 d-') against the composite parameter B Z, I,. Regressions for each estuary were significant and typically over 80 % of the varialon in P was correlated with variations in B Z,I,. Moreover, the pooled data (n = 211) from 4 estuaries where methodologies were comparable fell along one regression line (r2= 0.82), indicating that primary productivity can be estimated in a diversity of estuarine waters from simple measures of phytoplankton biomass and hght availability. This implies that physiological variabhty (e. g. responses to variations in nutrient availabhty, temperature, sahnity, photoperiod) is a secondary control on phytoplankton production in nutrient-rich estuaries, and that one empirical function can be used to estimate seasonal variations in productivity or to map productivity along estuarine gradients of phytoplankton biomass and turbidity.

  16. Future variability of solute transport in a macrotidal estuary

    NASA Astrophysics Data System (ADS)

    Robins, Peter E.; Lewis, Matt J.; Simpson, John H.; Howlett, Eleanor R.; Malham, Shelagh K.

    2014-12-01

    The physical controls on salt distribution and river-sourced conservative solutes, including the potential implications of climate change, are investigated referring to model simulations of a macrotidal estuary. In the UK, such estuaries typically react rapidly to rainfall events and, as such, are often in a state of non-equilibrium in terms of solute transport; hence are particularly sensitive to climate extremes. Sea levels are projected to rise over the 21st century, extending the salinity maximum upstream in estuaries, which will also affect downstream solute transport, promoting estuarine trapping and reducing offshore dispersal of material. Predicted 'drier summers' and 'wetter winters' in the UK will influence solute transport further still; we found that projected river flow climate changes were more influential than sea-level rise, especially for low flow conditions. Our simulations show that projected climate change for the UK is likely to increase variability in estuarine solute transport and, specifically, increase the likelihood of estuarine trapping during summer, mainly due to drier weather conditions. Future changes in solute transport were less certain during winter, since increased river flow will to some extent counter-act the effects of sea-level rise. Our results have important implications for non-conservative nutrient transport, water quality, coastal management and ecosystem resilience.

  17. Carbon dioxide emissions from estuaries of northern and northeastern Brazil

    PubMed Central

    Noriega, Carlos; Araujo, Moacyr

    2014-01-01

    The carbon dioxide flux through the air–water interface of coastal estuarine systems must be quantified to understand the regional balance of carbon and its transport through adjacent coastal regions. We estimated and calculated the emissions of carbon dioxide (FCO2) and the partial pressure of CO2 (pCO2) values in 28 estuarine environments at a variety of spatial scales in the northern and northeastern regions of Brazil. The results showed a mean FCO2 (water to air) of 55 ± 45 mmol·m−2·d−1. Additionally, a negative correlation between dissolved oxygen saturation and pCO2 was observed, indicating a control by biological processes and especially by organic matter degradation. This leads to increased dissolved CO2 concentration in estuarine waters which results in a pCO2 that reached 8,638 μatm. Our study suggests that northern and northeastern Brazilian estuaries act as sources of atmospheric CO2. The range of pCO2 observed were similar to those found in inner estuaries in other places around the world, with the exception of a few semi-arid estuaries (Köppen climate classification – BSh) in which record low levels of pCO2 have been detected. PMID:25145418

  18. Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity

    USGS Publications Warehouse

    Miselis, Jennifer L.; Andrews, Brian D.; Nicholson, Robert S.; Defne, Zafer; Ganju, Neil K.; Navoy, Anthony S.

    2016-01-01

    Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island morphologic response was characterized by significant changes in shoreline position, dune elevation, and beach volume; morphologic changes within the estuary were less dramatic with a net gain of only 200,000 m3 of sediment. When observed, estuarine deposition was adjacent to the back-barrier shoreline or collocated with maximum estuary depths. Estuarine sedimentologic changes correlated well with bed shear stresses derived from numerically simulated storm conditions, suggesting that change is linked to winnowing from elevated storm-related wave-current interactions rather than deposition. Rapid storm-related changes in estuarine water level, turbidity, and salinity were coincident with minima in island and estuarine widths, which may have influenced the location of two barrier island breaches. Barrier-estuary connectivity, or the transport of sediment from barrier island to estuary, was influenced by barrier island land use and width. Coupled assessments like this one provide critical information about storm-related coastal and estuarine sediment transport that may not be evident from investigations that consider only one component of the coastal system.

  19. Topographic monitoring of a middle estuary mudflat, Humber estuary, UK--anthropogenic impacts and natural variation.

    PubMed

    Boyes, Suzanne J; Allen, James H

    2007-01-01

    Annual topographic surveys were carried out at the Saltend mudflat (Humber estuary, UK) between 1998 and 2006. These surveys formed part of an ongoing monitoring programme to examine the potential effects on the mudflat topography of the construction and operation of a waste water treatment works (WwTW) development by Yorkshire Water. Of particular concern was the potential disruption to the sedimentological regime within the special protection area (SPA) and candidate special area of conservation (cSAC) which could affect the invertebrate communities and ornithological functioning of the site. In addition to the development of the WwTW located to the extreme north-west of the site, a port extension removing 10ha of the Saltend intertidal mudflat (outside the SPA but immediately south east of the WwTW) also occurred between 1999 and 2006. Minimal change was noted across the site following the construction and operation of the WwTW between 1998 and 2000. However, the construction of the bund in closer proximity to the SPA and cSAC masked any potential impact the WwTW could have had across the site after 2000. Profiles and contour mapping indicate that significant mudflat accretion occurred in the immediate area of the bund, with a general increase recorded across the western section of the site since 2000. In contrast the alternations to channel planform and subsequent rapid accretion of the mudflat to the east of the jetty, being a significant distance from the developments, are attributed to natural cyclical changes.

  20. Feasibility analysis of recycling radioactive scrap steel

    SciTech Connect

    Nichols, F.; Balhiser, B.; Cignetti, N.

    1995-09-01

    The purpose of this study is to: (1) establish a conceptual design that integrates commercial steel mill technology with radioactive scrap metal (RSM) processing to produce carbon and stainless steel sheet and plate at a grade suitable for fabricating into radioactive waste containers; (2) determine the economic feasibility of building a micro-mill in the Western US to process 30,000 tons of RSM per year from both DOE and the nuclear utilities; and (3) provide recommendations for implementation. For purposes of defining the project, it is divided into phases: economic feasibility and conceptual design; preliminary design; detail design; construction; and operation. This study comprises the bulk of Phase 1. It is divided into four sections. Section 1 provides the reader with a complete overview extracting pertinent data, recommendations and conclusions from the remainder of the report. Section 2 defines the variables that impact the design requirements. These data form the baseline to create a preliminary conceptual design that is technically sound, economically viable, and capitalizes on economies of scale. Priorities governing the design activities are: (1) minimizing worker exposure to radionuclide hazards, (2) maximizing worker safety, (3) minimizing environmental contamination, (4) minimizing secondary wastes, and (5) establishing engineering controls to insure that the plant will be granted a license in the state selected for operation. Section 3 provides details of the preliminary conceptual design that was selected. The cost of project construction is estimated and the personnel needed to support the steel-making operation and radiological and environmental control are identified. Section 4 identifies the operational costs and supports the economic feasibility analysis. A detailed discussion of the resulting conclusions and recommendations is included in this section.

  1. Short-term variations of phytoplankton communities in response to anthropogenic stressors in a highly altered temperate estuary

    NASA Astrophysics Data System (ADS)

    Sin, Yongsik; Jeong, Byungkwan

    2015-04-01

    Data for phytoplankton size classes, taxonomy, and water properties were collected through an episodic freshwater discharge event (4 days) in the temperate Youngsan River estuary, which is highly disturbed by manually regulated inputs of freshwater from a sea dike, to investigate the effects of an acute change in anthropogenic stressors on the short-term dynamics of phytoplankton and their surrounding environments. The salinity of the well-mixed saline water (33.2-33.5) decreased to as low as 4.0 and water temperature increased to 24.0 °C during the freshwater discharge, resulting in a stratified water column in the upper region of the estuary. During the discharge, chlorophyll a (chl a) concentrations increased to as much as 15.66 μg L-1 with micro-sized phytoplankton being dominant due to the presence of micro-sized freshwater phytoplankton, mostly Aulacoseira ambigua (98% in cell abundance), transported from the reservoir. Primary production decreased to as little as 87.9 mg C m-2 d-1, although nutrients such as NO2- + NO3- were supplied by the freshwater inputs of the discharge. Following the discharge, dinoflagellate blooms, dominated by Heterocapsa sp. (>88%), a nano-sized red tide species, developed in the upper regions of the estuary with peaks in chl a concentrations reaching as high as 30.33 μg L-1. Another red tide species, Prorocentrum micans, was also dominant in the estuary, suggesting that harmful algal blooms (HABs) are associated with anthropogenic stressors related to the freshwater inputs. The Shannon diversity index decreased to 0.18 while the Simpson dominance index increased to 0.94 during the discharge, but the diversity increased again following the discharge. The phytoplankton communities and diversity changed along the salinity gradient, corresponding to an "ecocline" pattern. The results of multivariate statistical analysis suggested that phytoplankton species and size structure were controlled mainly by salinity, water temperature

  2. RELATIONS OF FISH AND SHELLFISH DISTRIBUTIONS TO HABITAT AND WATER QUALITY IN THE MOBILE BAY ESTUARY, USA

    EPA Science Inventory

    The Mobile Bay estuary provides rich habitat for many fish and shellfish, including those identified as economically and ecologically important. The National Estuary Program has focused on restoration of degraded estuarine habitat on which these species depend. To support this ...

  3. Size Matters: The Contribution of Mega-Infauna to the Food Webs and Ecosystem Services of an Oregon Estuary

    EPA Science Inventory

    Large-bodied, invertebrates are common to infaunal communities of NE Pacific estuaries (e.g., bivalves, polychaetes, burrowing shrimps), but their contribution to the ecological structure, function and ecosystem services of most estuaries has been poorly characterized because the...

  4. Variation in tidal wetland plant diversity and composition within and among coastal estuaries: assessing the relative importance of environmental gradients

    EPA Science Inventory

    Question: Does wetland plant composition vary more by estuarine type (differentiated by the degree of riverine versus oceanic influence) or habitat type within estuaries (defined by US National Wetlands Inventory [NWI] marsh classes)? Location: Oregon estuaries: Netarts Bay, ...

  5. Estuaries of the northeastern United States: Habitat and land use signatures

    USGS Publications Warehouse

    Roman, C.T.; Jaworski, N.; Short, F.T.; Findlay, S.; Warren, R.S.

    2000-01-01

    Geographic signatures are physical, chemical, biotic, and human-induced characteristics or processes that help define similar or unique features of estuaries along latitudinal or geographic gradients. Geomorphologically, estuaries of the northeastern U.S., from the Hudson River estuary and northward along the Gulf of Maine shoreline, are highly diverse because of a complex bedrock geology and glacial history. Back-barrier estuaries and lagoons occur within the northeast region, but the dominant type is the drowned-river valley, often with rocky shores. Tidal range and mean depth of northeast estuaries are generally greater when compared to estuaries of the more southern U.S. Atlantic coast and Gulf of Mexico. Because of small estuarine drainage basins, low riverine flows, a bedrock substrate, and dense forest cover, sediment loads in northeast estuaries are generally quite low and water clarity is high. Tidal marshes, seagrass meadows, intertidal mudflats, and rocky shores represent major habitat types that fringe northeast estuaries, supporting commercially-important fauna, forage nekton and benthos, and coastal bird communities, while also serving as links between deeper estuarine waters and habitats through detritus-based pathways. Regarding land use and water quality trends, portions of the northeast have a history of over a century of intense urbanization as reflected in increased total nitrogen and total phosphorus loadings to estuaries, with wastewater treatment facilities and atmospheric deposition being major sources. Agricultural inputs are relatively minor throughout the northeast, with relative importance increasing for coastal plain estuaries. Identifying geographic signatures provides an objective means for comparing the structure function, and processes of estuaries along latitudinal gradients.

  6. Land use and nitrogen loading in seven estuaries along the southern Gulf of St. Lawrence, Canada

    NASA Astrophysics Data System (ADS)

    McIver, Reba; Milewski, Inka; Lotze, Heike K.

    2015-11-01

    Nitrogen loading from coastal watersheds is a principal factor associated with the decline in eelgrass bed health and cover in estuaries worldwide. We apply the Nitrogen Loading Model (NLM) framework developed in Waquoit Bay, Massachusetts to 7 estuaries in eastern New Brunswick. Using watershed-specific information on human population, wastewater production, atmospheric deposition, and land use in each watershed we estimate annual input of Total Dissolved Nitrogen (TDN) from point and non-point sources. We also estimate flushing time of each estuary using available hydrodynamic and bathymetric data incorporated in a tidal prism model. Finally, we validate the NLM results by testing the link between estimated nitrogen loading, flushing time and nitrogen signals in eelgrass tissue including nitrogen content and stable isotopes. Overall, total nitrogen load (kg TDN yr-1) was strongly dependent on watershed and estuary size, while loading rate per unit watershed area (yield) was linked to watershed population density. Atmospheric deposition was the largest contributor of nitrogen to all estuaries except one, where seafood processing effluent was the greatest source. Stable isotope analysis of eelgrass tissue reflected this distinction, with high δ15N values of 8-10‰ related to high wastewater loading, compared to 2-6.5‰ in the other estuaries that receive proportionally more atmospheric deposition. Tissue nitrogen content was positively related to nitrogen yields and loading rate per volume of estuary, highlighting the influence of variable watershed:estuary size ratio. Multiple regression analysis identified a significant interaction between nitrogen yield and flushing time on eelgrass tissue nitrogen content and isotopes, pointing to the mitigating effect an estuary's quick flushing time can have on the expression of nitrogen enrichment in primary producers. The compilation of new information on nitrogen loading to east Canadian estuaries is a novel

  7. Effects of artificial openings of intermittently opening estuaries on macroinvertebrate assemblages of the entrance barrier

    NASA Astrophysics Data System (ADS)

    Gladstone, William; Hacking, Nicole; Owen, Vanessa

    2006-05-01

    Intermittently opening estuaries are artificially opened to manage flood risk, water quality, recreational amenity, and fisheries; however, the ecological impacts of this management technique are incompletely understood. During 2001 and 2004, this study assessed the impacts of artificial openings on the macroinvertebrates of entrance barriers of intermittently opening estuaries in New South Wales (Australia). In 2001 macroinvertebrates were sampled once before artificial opening and 9 and 25 d after re-formation of the entrance barrier. A multiple before-after-control-impact analysis found that, although entrance barriers were destroyed by the artificial openings and then re-formed naturally by wave action, significant interactions for taxonomic richness, density of the amphipod Paracalliope australis (Gammaridae) and density of the gastropod mollusc Aschoris victoriae (Hydrobiidae) meant that the effects of this disturbance could not be distinguished from the natural variations that occurred in unopened estuaries. Multivariate analyses found that assemblages at both opened and unopened estuaries changed from before to after the openings, and the magnitude of the dissimilarity between times varied between estuaries. In 2004, macroinvertebrates were sampled on three randomly selected days within each of three periods (before, 3 d and 42 d after) at one opened and three unopened estuaries. Asymmetrical analysis of this modified before-after-control-impact study found that the change in taxonomic richness at the opened estuary from before to after opening did not differ from temporal changes that occurred in unopened estuaries. Short-term variation (i.e. between days) in total density of macroinvertebrates and density of P. australis in the re-formed entrance barrier of the opened estuary also did not differ from the variation in the control estuaries. Additionally, assemblage structure was not significantly changed by the opening and assemblages at two control

  8. Hydrobiological characteristics of Shark River estuary, Everglades National Park, Florida

    USGS Publications Warehouse

    McPherson, B.F.

    1970-01-01

    Water quality in the Shark River estuary was strongly influenced by seasonal patterns of rainfall, water level and temperature. During the rainy season (summer and early fall) the salinity in the 20-mile long estuary ranged from that of fresh water to half that of sea water while concentrations of dissolved oxygen were low, 2-5 milligrams per liter (mg/l) presumably because, among other factors, microbial activity and respiration were accelerated by high temperatures (30-33 degrees C). During the dry season (late fall through spring) the salinity ranged from 18 grams per liter (g/l) in the headwaters to 36 g/l at the Gulf during a dry year such as 1967 and from 1 to 25 g/l during a wet year such as 1969. Concentrations of dissolved oxygen increased from 2-3 mg/l in the summer of 1967 to 4-7 mg/l in the winter of 1968, and temperature decreased from an average of about 30 degrees C in summer to 20 degrees C in winter. Water level declined 5 to 10 decimeters in the headwaters during the dry season, and salinity and tidal action increased. Large amounts of submerged vegetation died in some headwater creeks at the end of the dry season, presumably killed by salinities above 3 g/l. The decaying organic matter and the decrease in photosynthesis resulted in low dissolved oxygen (1-2 mg/l). Fish died at this time probably as a result of the low dissolved oxygen. Trace elements, heavy metals and insecticides occurred in the waters of the estuary in concentrations below those indicated as harmful for aquatic life by current standards established by the Federal Water Pollution Control Administration (1968). The insecticides detected were concentrated in sediment and in various organisms. The patterns of distribution of planktonic and small nektonic animals in the estuary were related to salinity. Copepods (Arcatia tonsa, Labidocera aestiva, Pseudodiaptomus coronatus), cumaceans (Cyclaspis sp.), chaetognaths (Sagitta hispida), bay anchovies (Anchoa mitchilli), and scaled

  9. Silver behaviour along the salinity gradient of the Gironde Estuary.

    PubMed

    Lanceleur, Laurent; Schäfer, Jörg; Blanc, Gérard; Coynel, Alexandra; Bossy, Cécile; Baudrimont, Magalie; Glé, Corine; Larrose, Aurélie; Renault, Sophie; Strady, Emilie

    2013-03-01

    Dissolved and particulate Ag concentrations (Ag(D) and Ag(P), respectively) were measured in surface water and suspended particulate matter (SPM) along the salinity gradient of the Gironde Estuary, South West France, during three cruises (2008-2009) covering contrasting hydrological conditions, i.e. two cruises during intermediate and one during high freshwater discharge (~740 and ~2,300 m(3)/s). Silver distribution reflected non-conservative behaviour with 60-70 % of Ag(P) in freshwater particles being desorbed by chlorocomplexation. The amount of Ag(P) desorbed was similar to the so-called reactive, potentially bioavailable Ag(P) fraction (60 ± 4 %) extracted from river SPM by 1 M HCl. Both Ag(P) (0.22 ± 0.05 mg/kg) and Ag(P)/Th(P) (0.025-0.028) in the residual fraction of fluvial and estuarine SPM were similar to those in SPM from the estuary mouth and in coastal sediments from the shelf off the Gironde Estuary, indicating that chlorocomplexation desorbs the reactive Ag(P). The data show that desorption of reactive Ag(P) mainly occurs inside the estuary during low and intermediate discharge, whereas expulsion of partially Ag(P)-depleted SPM (Ag(P)/Th(P) ~0.040) during the flood implies ongoing desorption in the coastal ocean, e.g. in the nearby oyster production areas (Marennes-Oléron Bay). The highest Ag(D) levels (6-8 ng/L) occurred in the mid-salinity range (15-20) of the Gironde Estuary and were decoupled from freshwater discharge. In the maximum turbidity zone, Ag(D) were at minimum, showing that high SPM concentrations (a) induce Ag(D) adsorption in estuarine freshwater and (b) counterbalance Ag(P) desorption in the low salinity range (1-3). Accordingly, Ag behaviour in turbid estuaries appears to be controlled by the balance between salinity and SPM levels. The first estimates of daily Ag(D) net fluxes for the Gironde Estuary (Boyle's method) showed relatively stable theoretical Ag(D) at zero salinity (Ag (D) (0) = 25-30 ng/L) for the contrasting

  10. Conceptualizing the Structure of Coupled Estuary, Coast and Inner Shelf Sediment Systems

    NASA Astrophysics Data System (ADS)

    French, J.; Burningham, H.

    2013-12-01

    The concept of the coastal cell has endured for 50 years as a geomorphological framework for coastal engineering and management. Cells are readily defined for coasts dominated by alongshore transport of beach-grade material, but the concept struggles to accommodate long range cohesive sediment fluxes. Moreover, the challenges of predicting, understanding and mitigating climate change impacts at the coast demand a richer conceptualization that embraces the connectedness of open coasts with estuaries and the inner shelf at broader scales and that also acknowledges the extent of anthropogenic control. Accordingly, this paper presents a new approach that re-engages with formal systems analysis and restores a geomorphological focus to coastal management problems that have latterly been tackled primarily by engineers. At the heart of this approach is an ontology of landforms and interventions (both structural and non-structural) that is partly inspired by the coastal tract concept and its temporal hierarchy of sediment sharing systems, but which also emphasizes a spatial hierarchy in scale, from coastal regions, through landform complexes, to landforms and human interventions. The complex web of interactions is represented through an influence network in which a sub-set of mass transfer pathways define the sediment system. Guided by a machine-readable ontology and produced within a geospatial framework, such system ';maps' can be utilized in several ways. First, their generation constitutes a form of knowledge formalization in which disparate sources of information (published research, data etc) are generalized into usable knowledge. Second, system maps also provide a repository for more quantitative analyses and system-level modelling at the scales that really matter. Third, they can also be analyzed using methods derived from graph theory to yield potentially valuable insights into the scale linkages that govern the mutual adjustment of estuary, coast and inner shelf

  11. Dwarf eelgrass, Zostera japonica: a malevolent, benevolent, or benign invasive ecosystem engineer?

    EPA Science Inventory

    Dwarf eelgrass, Zostera japonica, is an introduced ecosystem engineering species first reported on the US west coast in 1957. In some US Pacific Northwest estuaries its areal coverage now exceeds that of the native eelgrass species, Zostera marina. Natural resource management’s...

  12. KE Basin water dispositioning engineering study

    SciTech Connect

    Hunacek, G.S.; Gahir, S.S.

    1994-09-23

    This engineering study is a feasibility study of KE Basin water treatment to an acceptable level and dispositioning the treated water to Columbia River, ground through ETF or to air through evaporation.

  13. A sublimation heat engine

    NASA Astrophysics Data System (ADS)

    Wells, Gary G.; Ledesma-Aguilar, Rodrigo; McHale, Glen; Sefiane, Khellil

    2015-03-01

    Heat engines are based on the physical realization of a thermodynamic cycle, most famously the liquid-vapour Rankine cycle used for steam engines. Here we present a sublimation heat engine, which can convert temperature differences into mechanical work via the Leidenfrost effect. Through controlled experiments, quantified by a hydrodynamic model, we show that levitating dry-ice blocks rotate on hot turbine-like surfaces at a rate controlled by the turbine geometry, temperature difference and solid material properties. The rotational motion of the dry-ice loads is converted into electric power by coupling to a magnetic coil system. We extend our concept to liquid loads, generalizing the realization of the new engine to both sublimation and the instantaneous vapourization of liquids. Our results support the feasibility of low-friction in situ energy harvesting from both liquids and ices. Our concept is potentially relevant in challenging situations such as deep drilling, outer space exploration or micro-mechanical manipulation.

  14. A sublimation heat engine.

    PubMed

    Wells, Gary G; Ledesma-Aguilar, Rodrigo; McHale, Glen; Sefiane, Khellil

    2015-03-03

    Heat engines are based on the physical realization of a thermodynamic cycle, most famously the liquid-vapour Rankine cycle used for steam engines. Here we present a sublimation heat engine, which can convert temperature differences into mechanical work via the Leidenfrost effect. Through controlled experiments, quantified by a hydrodynamic model, we show that levitating dry-ice blocks rotate on hot turbine-like surfaces at a rate controlled by the turbine geometry, temperature difference and solid material properties. The rotational motion of the dry-ice loads is converted into electric power by coupling to a magnetic coil system. We extend our concept to liquid loads, generalizing the realization of the new engine to both sublimation and the instantaneous vapourization of liquids. Our results support the feasibility of low-friction in situ energy harvesting from both liquids and ices. Our concept is potentially relevant in challenging situations such as deep drilling, outer space exploration or micro-mechanical manipulation.

  15. ECOLOGICAL CONDITION OF THE U.S. MID-ATLANTIC ESTUARIES: THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA)

    EPA Science Inventory

    The Mid-Atlantic Integrated Assessment (MAIA-Estuaries) evaluated ecological conditions in US Mid-Atlantic estuaries during the summers of 1997 and 1998. Over 800 probability-based stations were monitored in four main estuarine systems?Chesapeake Bay, the Delaware Estuary, Maryla...

  16. E-Estuary: Developing a Decision Support System for Coastal Management in the Conterminous United States (IAHR)

    EPA Science Inventory

    Ready access to geographic information is needed to support management decisions for estuaries at local, state, regional, and national scales. The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary ...

  17. E-Estuary: Developing a Decision-support System for Coastal Management in the Counterminous Untied States (Coastal Geotools 09)

    EPA Science Inventory

    Ready access to geographic information is needed to support management decisions for estuaries at local, state, regional, and national scales. The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary ...

  18. E-estuary: A Decision Support System for Coastal Water and Ecosystem Management in the US (CZ09)

    EPA Science Inventory

    Ready access to geographic information is needed to support management decisions for estuaries at local, state, regional, and national scales. The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary ...

  19. WestuRe: U.S. Pacific Coast estuary/watershed data and R tools

    EPA Science Inventory

    There are about 350 estuaries along the U.S. Pacific Coast. Basic descriptive data for these estuaries, such as their size and watershed area, are important for coastal-scale research and conservation planning. However, this information is spread among many sources and can be dif...

  20. Linking Data Access to Data Models to Applications: The Estuary Data Mapper

    EPA Science Inventory

    The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary has three elements: an estuarine geo-referenced relational database, watershed GIS coverages, and tools to support decision-making. To facilita...

  1. Demonstration and Hands-on Exercises with the Estuary Data Mapper

    EPA Science Inventory

    The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for applications of the Clean Water Act in coastal management. E-Estuary has three elements: an estuarine geo-referenced relational database, watershed GIS coverages, and tools t...

  2. Water pollution in estuaries and coastal zones. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1996-02-01

    The bibliography contains citations concerning the studies of water pollution in estuaries and coastal zones. Citations examine the development, management, and protection of estuary and coastal resources. Topics include pollution sources, environmental monitoring, water chemistry, eutrophication, models, land use, government policy, and laws and regulations. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  3. Concentration and Distribution of Hydrophobic Organic Contaminants and Metals in the Estuaries of Ukraine

    EPA Science Inventory

    In this baseline study of Ukrainian estuaries, sediments and organisms from the Dnieper and Boh estuaries and Danube Delta on the mainland, Sevastopol and Balaklava Bays on the Crimean Peninsula, and coastal Black Sea along the Crimean Peninsula were collected in 2006. Contamina...

  4. Environmental monitoring and assessment program (EMAP) laboratory methods manual estuaries. Volume 1. Biological and physical analyses

    SciTech Connect

    Strobel, C.J.; Klemm, D.J.; Lobring, L.B.; Eichelberger, J.W.; Alford-Stevens, A.

    1995-08-01

    This document is intended to document analytical methods for use by laboratories conducting analyses for the Environmental Monitoring and Assessment Program-Estuaries. This document is volume I of a two-part series. The second volume of the EMAP-Estuaries Laboratory Methods Manual presents methods for the chemical analyses of sediments and tissue.

  5. Propagation of tidal waves up in Yangtze Estuary during the dry season

    NASA Astrophysics Data System (ADS)

    Lu, Sheng; Tong, Chaofeng; Lee, Dong-Young; Zheng, Jinhai; Shen, Jian; Zhang, Wei; Yan, Yixin

    2015-09-01

    Tide is one of the most important hydrodynamic driving forces and has unique features in the Yangtze Estuary (YE) due to the complex geometry of third-order bifurcations and four outlets. This paper characterizes the tidal oscillations, tidal dampening, tidal asymmetry, and tidal wave propagation, which provides insights into the response of the estuary to tides during the dry season. The structural components of tidal oscillations are initially attained by tidal analysis. The increasingly richer spectrum inside the estuary shows an energy transfer corresponding to the generation and development of nonlinear overtides and compound tides. A 2-D numerical model is further set up to reproduce tidal dynamics in the estuary. The results show that the estuary is a strongly dissipative estuary with a strong nonlinear phenomenon. Three amplifications are presented in the evolution process of tidal ranges due to the channel convergence. Tidal asymmetry is spatiotemporally characterized by the M4/M2 amplitude ratio, the 2M2-M4 phase difference, and the flood-ebb duration-asymmetry parameter, and the estuary tends to be flood-dominant. There exists mimic standing waves with the phase difference of the horizontal and vertical tide close to 90° when tidal wave propagates into the estuary, especially during the neap tide. In addition, the differences in tidal distortion, tidal ranges, and tidal waves along the two routes in the South Branch (S-B) suggest the branched system behaves differently from a single system.

  6. Report on benthic survey/sampling at Coquille Estuary, OR: June 30-July 3, 2008

    EPA Science Inventory

    Zostera japonica is a non-native seagrass first reported in the PNW in Willapa Bay in 1957 (Harrison and Bigley 1982). Since the, Z. japonica has been reported from 16 estuaries in the PNW (Lee and Reusser 2007), including the Yaquina Estuary in 1974-1975 (Bayer 1996). Besides ...

  7. Transport of fallout and reactor radionuclides in the drainage basin of the Hudson River estuary

    SciTech Connect

    Simpson, H.J.; Linsalata, P.; Olsen, C.R.

    1982-01-01

    The transport and fate of Strontium 90, Cesium 137 and Plutonium 239, 240 in the Hudson River Estuary is discussed. Rates of radionuclide deposition and accumulation over time and space are calculated for the Hudson River watershed, estuary, and continental shelf offshore. 37 references, 7 figures, 15 tables. (ACR)

  8. DEVELOPING NUTRIENT CRIETERIA FOR ESTUARIES WITH VARIABLE OCEAN INPUTS: AN EXAMPLE FROM THE PACIFIC NORTHWEST

    EPA Science Inventory

    Estuaries in the Pacific Northwest have major intraannual and within estuary variation in sources and magnitudes of nutrient inputs. To develop an approach for setting nutrient criteria for these systems, we conducted a case study for Yaquina Bay, OR based on a synthesis of resea...

  9. RELATIONSHIPS BETWEEN SEAGRASSES, BENTHIC MACROALGAE AND NUTRIENTS IN A PACIFIC NORTHWEST ESTUARY

    EPA Science Inventory

    Pacific Northwest estuaries are characterized by large tidal ranges (2-3 m) that routinely expose submerged aquatic vegetation (SAV) such as seagrass and benthic macroalgae. The dominant native seagrass in PNW estuaries is the eelgrass Zostera marina. However, in recent decades...

  10. Modeling Diel Oxygen Dynamics and Ecosystem Metabolism in a Shallow, Eutrophic Estuary

    EPA Science Inventory

    Weeks Bay is a shallow eutrophic estuary that exhibits frequent summertime diel-cycling hypoxia and periods of dissolved oxygen (DO) oversaturation during the day. Diel DO dynamics in shallow estuaries like Weeks Bay are complex, and may be influenced by wind forcing, vertical an...

  11. MODELING FISH AND SHELLFISH DISTRIBUTIONS IN THE MOBILE BAY ESTUARY, USA

    EPA Science Inventory

    Estuaries in the Gulf of Mexico provide rich habitat for many fish and shellfish, including those that have been identified as economically and ecologically important. For the Mobile Bay estuary, we developed statistical models to relate distributions of individual species and sp...

  12. REGIONAL TRANSPORT AND SECONDARY SPREAD OF INVASIVE SPECIES ACROSS PACIFIC ESTUARIES

    EPA Science Inventory

    San Francisco Bay is considered to be the most highly invaded estuary in North America, and is suspected of acting as a local source pool for secondary invasions of other Pacific estuaries. With support from the Regional Applied Research Effort programs in EPA Regions 9 and 10, ...

  13. Estuary Data Mapper: A virtual portal to coastal data informing environmental management decisions

    EPA Science Inventory

    The Estuary Data Mapper (EDM) is a free, interactive graphical application under development at the US EPA that allows environmental researchers and managers to quickly and easily retrieve, view and save subsets of online US coastal estuary-related data. Accessible data include ...

  14. CONDITION OF THE MID ATLANTIC ESTUARIES: PRODUCTION OF A STATE OF THE ENVIRONMENT REPORT

    EPA Science Inventory

    The U.S. Environmental Protection Agency has released a report entitled Condition of the Mid-Atlantic Estuaries. That report summarizes the findings of several studies conducted by federal and state agencies and academic institutions in Chesapeake Bay, Delaware Estuary, and the c...

  15. Benthic macrofaunal dynamics and environmental stress across a salt wedge Mediterranean estuary.

    PubMed

    Nebra, Alfonso; Alcaraz, Carles; Caiola, Nuno; Muñoz-Camarillo, Gloria; Ibáñez, Carles

    2016-06-01

    The spatial distribution of benthic macroinvertebrate community in relation to environmental factors was studied along the Ebro Estuary (NE Iberian Peninsula), a salt wedge Mediterranean estuary. Both ordination methods and generalized additive models were performed to identify the different benthic assemblages and their relationship to abiotic factors. Our results showed a strong relationship between macrofaunal assemblages and the predominant environmental gradients (e.g. salinity); thus revealing spatial differences in their structure and composition. Two different stretches were identified, namely the upper (UE) and the lower Ebro Estuary (LE). UE showed riverine characteristics and hence was colonized by a freshwater community; whereas LE was influenced by marine intrusion and sustained a complex marine-origin community. However, within each stretch, water and sediment characteristics played an important role in explaining species composition differences among sampling stations. Moreover, outcomes suggested a total species replacement pattern, instead of the nestedness pattern usually associated with well-mixed temperate estuaries. The sharp species turnover together with the estuarine stratification point out that the Ebro Estuary is working, in terms of ecological boundaries, under an ecotone model. Finally, despite obvious differences with well mixed estuaries (i.e. lack of tidal influence, stratification and species turnover), the Ebro Estuary shares important ecological attributes with well-mixed temperate estuaries.

  16. EFFECTS OF EROSION AND MACROALGAE ON INTERTIDAL EELGRASS (ZOSTERA MARINA) IN A NORTHEASTERN PACIFIC ESTUARY (USA)

    EPA Science Inventory

    Eelgrass (Zostera marina) in open-coast northeastern Pacific estuaries is primarily intertidal, yet little research has been done on the natural factors controlling its upper intertidal growth limits. This two-year study in the Yaquina Estuary (Newport, Oregon, USA) evaluated the...

  17. Developing Nitrogen Load-Eelgrass Response Relationshups for New England Estuaries

    EPA Science Inventory

    We have accumulated and analyzed eelgrass areal extent data for 67 estuaries from three New England states. To our knowledge this is the largest data set of its kind. Previous comparative studies have utilized data from a far smaller number of estuaries (ten or less) to develop e...

  18. Second international symposium on the biogeochemistry of model estuaries: Estuarine processes in global change

    SciTech Connect

    Not Available

    1991-12-31

    This report consists of abstracts of papers presented at the symposium of Biogeochemistry. The main topics discussed at the meeting are; nutrient and mineral cycling, trace element distribution, sources and sinks of estuaries, sedimentation, importance of organic matter, and other biogeochemical processes of estuaries.

  19. An approach to developing nutrient criteria for Pacific Northwest Estuaries: A case study

    EPA Science Inventory

    This presentation provides an overview of an approach to developing nutrient criteria for Pacific Northwest (PNW) estuaries, based on a case study of Yaquina Estuary, Oregon. The approach is based on a synthesis of research from field studies, analyses of historical trends in wat...

  20. Mapping ecosystem services in a Great Lakes estuary supports local decision-making

    EPA Science Inventory

    Estuaries of the Laurentian Great Lakes provide a concentrated supply of ecosystem goods and services from which humans benefit. As long-term centers of human activity, most estuaries of the Great Lakes and have a legacy of chemical contamination, degraded habitats, and non-point...

  1. Potential Climate-Induced Runoff Changes and Associated Uncertainty in Four Pacific Northwest Estuaries

    EPA Science Inventory

    As part of a larger investigation into potential impacts of climate change on estuarine habitats in the Pacific Northwest (PNW), we estimated changes in freshwater inputs into four estuaries. These were the Coquille River estuary, the South Slough of Coos Bay, and the Yaquina Bay...

  2. A CLASSIFICATION OF U.S. ESTUARIES BASED ON PHYSICAL, HYDROLOGIC ATTRIBUTES

    EPA Science Inventory

    A classification of U.S. estuaries is presented based on estuarine characteristics that have been identified as important for quantifying stressor-response

    relationships in coastal systems. Estuaries within a class have similar physical/hydrologic and land use characteris...

  3. Stable Isotope Identification of Nitrogen Sources for United States (U.S.) Pacific Coast Estuaries

    EPA Science Inventory

    We used natural abundance stable isotope data to evaluate nitrogen sources to U.S. west coast estuaries. We collected δ15N of macroalgae data and supplemented this with available data from the literature for estuaries from Mexico to Alaska. Stable isotope ratios of green m...

  4. Feasibility Investigation into Strengthening of Timber Bridge Stringers

    DTIC Science & Technology

    2007-05-01

    70%, respectively (Sonti and GangaRao 1996; Qiao, Davalos , and Zipfel 1998; Davalos , Zipfel, and Qiao 1999; Chamarthy and GangaRao 2003). The use...Journal 24(7):45-53. Davalos , J. F., Zipfel, M. G., and Qiao, P. 1999. Feasibility Study of Prototype GFRP- Reinforced Wood Railroad Crosstie. Journal of...Creep behavior of FRP-reinforced wood members. Journal of Structural Engineering 121(2). Qiao, P., Davalos , J. F., and Zipfel, M. G. 1998. Modeling and

  5. FEASIBILITY STUDY OF PRESSURE PULSING PIPELINE UNPLUGGING TECHNOLOGIES FOR HANFORD

    SciTech Connect

    Servin, M. A.; Garfield, J. S.; Golcar, G. R.

    2012-12-20

    The ability to unplug key waste transfer routes is generally essential for successful tank farms operations. All transfer lines run the risk of plugging but the cross site transfer line poses increased risk due to its longer length. The loss of a transfer route needed to support the waste feed delivery mission impacts the cost and schedule of the Hanford clean up mission. This report addresses the engineering feasibility for two pressure pulse technologies, which are similar in concept, for pipeline unplugging.

  6. Lower Sioux Wind Feasibility & Development

    SciTech Connect

    Minkel, Darin

    2012-04-01

    This report describes the process and findings of a Wind Energy Feasibility Study (Study) conducted by the Lower Sioux Indian Community (Community). The Community is evaluating the development of a wind energy project located on tribal land. The project scope was to analyze the critical issues in determining advantages and disadvantages of wind development within the Community. This analysis addresses both of the Community's wind energy development objectives: the single turbine project and the Commerical-scale multiple turbine project. The main tasks of the feasibility study are: land use and contraint analysis; wind resource evaluation; utility interconnection analysis; and project structure and economics.

  7. What does impacted look like? High diversity and abundance of epibiota in modified estuaries.

    PubMed

    Clark, Graeme F; Kelaher, Brendan P; Dafforn, Katherine A; Coleman, Melinda A; Knott, Nathan A; Marzinelli, Ezequiel M; Johnston, Emma L

    2015-01-01

    Ecosystems modified by human activities are generally predicted to be biologically impoverished. However, much pollution impact theory stems from laboratory or small-scale field studies, and few studies replicate at the level of estuary. Furthermore, assessments are often based on sediment contamination and infauna, and impacts to epibiota (sessile invertebrates and algae) are seldom considered. We surveyed epibiota in six estuaries in south-east Australia. Half the estuaries were relatively pristine, and half were subject to internationally high levels of contamination, urbanisation, and industrialisation. Contrary to predictions, epibiota in modified estuaries had greater coverage and were similarly diverse as those in unmodified estuaries. Change in epibiota community structure was linearly correlated with sediment-bound copper, and the tubeworm Hydroides elegans showed a strong positive correlation with sediment metals. Stressors such as metal contamination can reduce biodiversity and productivity, but others such as nutrient enrichment and resource provision may obscure signals of impact.

  8. Detecting benthic community responses to pollution in estuaries: a field mesocosm approach.

    PubMed

    O'Brien, Allyson L; Keough, Michael J

    2013-04-01

    Biological stress responses in individuals are used as indicators of pollution in aquatic ecosystems, but detecting ecologically relevant responses in whole communities remains a challenge. We developed an experimental approach to detect the effects of pollution on estuarine communities using field-based mesocosms. Mesocosms containing defaunated sediments from four estuaries in southeastern Australia that varied in sediment contamination were transplanted and buried in sediments of the same four estuaries for six weeks. Mesocosm sediment properties and metal concentrations remained representative of their source locations. In each estuary, fauna communities associated with sediments derived from the site with the highest metal concentrations were significantly different from other communities. This pattern was evident for some of the individual taxa, in particular the polychaete Capitella sp. Consistent responses across estuaries suggest numbers of individuals, and especially Capitella sp., could be used to identify contaminated sediments in estuaries with similar fauna and site characteristics.

  9. Decadal changes in nutrient fluxes and environmental effects in the Jiulong River Estuary.

    PubMed

    Wu, Gaojie; Cao, Wenzhi; Huang, Zheng; Kao, Chih-Ming; Chang, Chang-Tang; Chiang, Pen-Chi; Wang, Feifei

    2017-02-04

    Estuaries are areas of both freshwater and seawater that are partially enclosed with contact to the open sea and a flow of fresh water. Although the Jiulong River Estuary has a relatively small catchment, this area was found to exhibit high nutrient fluxes. The nutrient fluxes showed obvious fluctuations for different years. The Jiulong River Estuary was predominantly P-limited, and was slowly moving towards higher DIN:DIP and DSi:DIP ratios as the nitrate concentrations increased. The high nutrient fluxes into the estuary may affect estuarine ecosystems by the alteration of DO concentrations in bottom waters, causing harm to benthic fauna due to a lack of oxygen, triggering algal blooms. Additionally, the Jiulong River Estuary was slowly moving towards lower DSi:DIN and DSi:DIP ratios along with the change of time scales, which caused nutrient limitation of phytoplankton growth as P and Si levels decreased and became more limiting.

  10. Studies on antioxidant status in Mugil cephalus in response to heavy metal pollution at Ennore estuary.

    PubMed

    Padmini, E; Usha Rani, M; Vijaya Geetha, B

    2009-08-01

    Estuaries, the important component of natural environment are under pressure nowadays due to pollution from different sources like industries, agricultural fields etc. Ennore estuary one of the highly polluted estuary situated in Chennai, Tamilnadu, India, due to heavy industrialization surrounding this site poses serious threat to its inhabitants. The present paper focuses on studying the response of the fish Mugil cephalus with reference to its antioxidants during their exposure to metals like iron and chromium present in the industrial effluents that are discharged into the Ennore estuary. The results on comparison with unpolluted Kovalam estuary showed that fish from Ennore experiences severe oxidative stress with significant alteration being observed with antioxidant enzyme activities. Since these results were also found to vary with seasons, the determination of oxidative stress biomarkers in M. cephalus along with seasonal variations may serve as a convenient approach during pollution biomonitoring programme.

  11. Cruise observation and numerical modeling of turbulent mixing in the Pearl River estuary in summer

    NASA Astrophysics Data System (ADS)

    Pan, Jiayi; Gu, Yanzhen

    2016-06-01

    The turbulent mixing in the Pearl River estuary and plume area is analyzed by using cruise data and simulation results of the Regional Ocean Model System (ROMS). The cruise observations reveal that strong mixing appeared in the bottom layer on larger ebb in the estuary. Modeling simulations are consistent with the observation results, and suggest that inside the estuary and in the near-shore water, the mixing is stronger on ebb than on flood. The mixing generation mechanism analysis based on modeling data reveals that bottom stress is responsible for the generation of turbulence in the estuary, for the re-circulating plume area, internal shear instability plays an important role in the mixing, and wind may induce the surface mixing in the plume far-field. The estuary mixing is controlled by the tidal strength, and in the re-circulating plume bulge, the wind stirring may reinforce the internal shear instability mixing.

  12. Sedimentary fabrics of the macrotidal, mud-dominated, inner estuary to fluvio-tidal transition zone, Petitcodiac River estuary, New Brunswick, Canada

    NASA Astrophysics Data System (ADS)

    Shchepetkina, Alina; Gingras, Murray K.; Zonneveld, John-Paul; Pemberton, S. George

    2016-03-01

    The study provides a detailed description of mud-dominated sedimentary fabrics and their application for the rock record within the inner estuary to the fluvial zone of the Petitcodiac River estuary, New Brunswick, Canada. Sedimentological characteristics and facies distributions of the clay- and silt-rich deposits are reported. The inner estuary is characterized by thick accumulations of interbedded silt and silty clay on intertidal banks that flank the tidally influenced channel. The most common sedimentary structures observed are parallel and wavy lamination, small-scale soft-sediment deformation with microfaults, and clay and silt current ripples. The tidal channel contains sandy silt and clayey silt with planar lamination, massive and convolute bedding. The fluvio-tidal transition zone is represented by interbedded trough cross-stratified sand and gravel beds with planar laminated to massive silty mud. The riverine, non-tidal reach of the estuary is characterized by massive, planar tabular and trough cross-stratified gravel-bed deposits. The absence of bioturbation within the inner estuary to the fluvio-tidal transition zone can be explained by the following factors: low water salinities (0-5 ppt), amplified tide and current speeds, and high concentrations of flocculated material in the water body. Notably, downstream in the middle and outer estuary, bioturbation is seasonally pervasive: in those locales the sedimentary conditions are similar, but salinity is higher. In this study, the sedimentological (i.e., grain size, bedding characters, sedimentary structures) differences between the tidal estuary and the fluvial setting are substantial, and those changes occur over only a few hundred meters. This suggests that the widely used concept of an extensive fluvio-tidal transition zone and its depositional character may not be a geographically significant component of fluvial or estuary deposits, which can go unnoticed in the study of the ancient rocks.

  13. Nutrient transport to the Swan - Canning Estuary, Western Australia

    USGS Publications Warehouse

    Peters, N.E.; Donohue, R.

    2001-01-01

    Catchment nutrient availability in Western Australia is primarily controlled by the disposal of animal waste and the type and rate of fertilizer application, particularly on the relatively narrow (~25 km wide), sandy coastal plain. Nitrogen (N) and phosphorous (P) concentrations and fluxes during the wet season of 15 tributaries, including four urban drains to the Swan-Canning Estuary, were evaluated from 1986 to 1992 and additionally concentrations only were evaluated throughout the year from 1993 to 1996. Concentrations of filtered reactive P (FRP) and total P (TP) were generally low, with the volume-weighted means for all sites being 0.06 mg 1-1 and 0.12 mg 1-1 respectively. The urban drains had higher TP concentrations (volume-weighted mean of 0.21 mg 1-1) than the streams (0.12 mg 1-1), with the high concentrations associated with particulate matter. Total inorganic N (TIN, NH4N plus NO3N) and total N (TN), which is of interest to eutrophic status of the N-limited estuary, were likewise low, compared with other developed areas having a similar climate. Both TIN and TN were higher in the urban drains (0.76 mg 1-1 and 1.5 mg 1-1 respectively) than the streams (0.31 mg 1-1 and 1.2 mg 1-1 respectively). The Avon River, which drains 98.5% of the 121 000 km2 catchment area, contributes most of the N (0.03 kg ha-1 year-1 or 65%) and a high percentage of the P (<0.01 kg ha-1 year-1 or 32%) to the estuaries. The Avon River nutrient fluxes are much less than other tributaries closer to the estuary. The coastal plain receives significantly higher rainfall (1,200 mm year-1) and has more intense horticulture and animal production than inland areas (<300 mm year-1). Annual rainfall is seasonal, occuring primarily from May through December. The surficial aquifers on the coastal plain generally are sandy with a low nutrient retention capacity, and rapidly transmit soluble and colloidal material in subsurface flow. Ellen Brook, on the coastal plain, drains pastures treated

  14. A framework for investigating general patterns of benthic β-diversity along estuaries

    NASA Astrophysics Data System (ADS)

    Barros, Francisco; Blanchet, Hugues; Hammerstrom, Kamille; Sauriau, Pierre-Guy; Oliver, John

    2014-08-01

    The description of major patterns in beta (β) diversity is important in order to understand changes in community composition and/or richness at different spatial and temporal scales, and can interrogate processes driving species distribution and community dynamics. Human impacts have pushed many estuarine systems far from their historical baseline of rich, diverse, and productive ecosystems. Despite the ecological and social importance of estuaries, there has not yet been an attempt to investigate patterns of β-diversity and its partitioning along estuarine systems of different continents. We aimed to evaluate if benthic assemblages would show higher turnover than nestedness in tropical than in temperate systems, if well-known impacted estuaries would show greater nestedness than less polluted systems, and to propose a conceptual framework for studying benthic macrofauna beta diversity along estuaries. We analyzed subtidal benthic macrofaunal data from estuaries in Brazil, USA and France. We estimated alpha (α), beta (β) and gamma (γ) diversity for each sampling time in each system, investigated patterns of β -diversity as multivariate dispersion and the partitioning (nestedness and replacement) of β-diversity along each estuary. There was a decrease in the α-diversity along marine to freshwater conditions at most of the estuaries and sampling dates. Beta diversity as multivariate dispersion showed high variability. Most of the estuaries showed a greater proportion of the β-diversity driven by replacement than nestedness. We suggest a conceptual framework for estuaries where relatively pristine estuaries would have their β-diversity mostly driven by replacement while impacted estuaries subjected to several anthropogenic stressors would show total nestedness or total replacement, depending on the stress.

  15. Heavy Metals (Cd, Cu, Cr, Pb and Zn) in Meretrix meretrix Roding, Water and Sediments from Estuaries in Sabah, North Borneo

    ERIC Educational Resources Information Center

    Abdullah, Mohd. Harun; Sidi, Jovita; Aris, Ahmad Zaharin

    2007-01-01

    Concentrations of heavy metals (Cd, Cu, Cr, Pb and Zn) in tissues of Meretrix meretrix Roding (M. meretrix R.), water and sediments from two estuaries were determined. One estuary is located in an urban area of Kota Kinabalu (Likas estuary) and the other in a rural district of Kota Belud (Kota Belud estuary), where both are in Sabah, North of…

  16. 7 CFR 4279.150 - Feasibility studies.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Feasibility studies. 4279.150 Section 4279.150... § 4279.150 Feasibility studies. A feasibility study by a qualified independent consultant may be required... affect the borrower's operations. An acceptable feasibility study should include, but not be limited...

  17. 7 CFR 4279.150 - Feasibility studies.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Feasibility studies. 4279.150 Section 4279.150... § 4279.150 Feasibility studies. A feasibility study by a qualified independent consultant may be required... affect the borrower's operations. An acceptable feasibility study should include, but not be limited...

  18. 7 CFR 4279.150 - Feasibility studies.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Feasibility studies. 4279.150 Section 4279.150... § 4279.150 Feasibility studies. A feasibility study by a qualified independent consultant may be required... affect the borrower's operations. An acceptable feasibility study should include, but not be limited...

  19. 7 CFR 4279.150 - Feasibility studies.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Feasibility studies. 4279.150 Section 4279.150... § 4279.150 Feasibility studies. A feasibility study by a qualified independent consultant may be required... affect the borrower's operations. An acceptable feasibility study should include, but not be limited...

  20. 7 CFR 4279.150 - Feasibility studies.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Feasibility studies. 4279.150 Section 4279.150... § 4279.150 Feasibility studies. A feasibility study by a qualified independent consultant may be required... affect the borrower's operations. An acceptable feasibility study should include, but not be limited...