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At least 1,009 records · Page 56Linked to original sources

Numerical simulation of the paleohydrology of glacial Lake Oshkosh, eastern Wisconsin, USA

Proglacial lakes, formed during retreat of the Laurentide ice sheet, evolved quickly as outlets became ice-free and the earth deformed through glacial isostatic adjustment. With high-resolution digital elevation models (DEMs) and GIS methods, it is possible to reconstruct the evolution of surface hydrology. When a DEM deforms through time as predicted by our model of viscoelastic earth relaxation, the entire surface hydrologic system with its lakes, outlets, shorelines and rivers also evolves without requiring assumptions of outlet position. The method is applied to proglacial Lake Oshkosh in Wisconsin (13,600 to 12,900??cal yr BP). Comparison of predicted to observed shoreline tilt indicates the ice sheet was about 400??m thick over the Great Lakes region. During ice sheet recession, each of the five outlets are predicted to uplift more than 100??m and then subside approximately 30??m. At its maximum extent, Lake Oshkosh covered 6600??km2 with a volume of 111??km3. Using the Hydrologic Engineering Center-River Analysis System model, flow velocities during glacial outburst floods up to 9??m/s and peak discharge of 140,000??m3/s are predicted, which could drain 33.5??km3 of lake water in 10??days and transport boulders up to 3??m in diameter. ?? 2007 University of Washington.

Quaternary Research↗

An overview of historical channel adjustment and selected hydraulic values in the Lower Sabine and Lower Brazos River Basins, Texas and Louisiana

The Sabine and Brazos are alluvial rivers; alluvial rivers are dynamic systems that adjust their geometry in response to changes in streamflow (discharge) and sediment load. In fluvial geomorphology, the term 'channel adjustment' refers to river channel changes in three geometric dimensions: (1) channel slope (profile); (2) the outline or shape, such as meandering or braided, projected on a horizontal plane (planform); and (3) cross-sectional form (shape). The primary objective of the study was to investigate how the channel morphology of these rivers has changed in response to reservoirs and other anthropogenic disturbances that have altered streamflow and sediment load. The results of this study are expected to aid ecological assessments in the lower Sabine River and lower Brazos River Basins for the Texas Instream Flow Program. Starting in the 1920s, several dams have been constructed on the Sabine and Brazos Rivers and their tributaries, and numerous bridges have been built and sometimes replaced multiple times, which have changed the natural flow regime and reduced or altered sediment loads downstream. Changes in channel geometry over time can reduce channel conveyance and thus streamflow, which can have adverse ecological effects. Channel attributes including cross-section form, channel slope, and planform change were evaluated to learn how each river's morphology changed over many years in response to natural and anthropogenic disturbances. Climate has large influence on the hydrologic regimes of the lower Sabine and lower Brazos River Basins. Equally important as climate in controlling the hydrologic regime of the two river systems are numerous reservoirs that regulate downstream flow releases. The hydrologic regimes of the two rivers and their tributaries reflect the combined influences of climate, flow regulation, and drainage area. Historical and contemporary cross-sectional channel geometries at 15 streamflow-gaging stations in the lower Sabine and lower Brazos River Basins were evaluated. An in-depth discussion of results from streamflow-gaging station 08028500 Sabine River near Bon Weir, Tex., is featured here as an example of the analyses that were done at each station.

Fact Sheet↗

A digital underwater video camera system for aquatic research in regulated rivers

We designed a digital underwater video camera system to monitor nesting centrarchid behavior in the Tallapoosa River, Alabama, 20 km below a peaking hydropower dam with a highly variable flow regime. Major components of the system included a digital video recorder, multiple underwater cameras, and specially fabricated substrate stakes. The innovative design of the substrate stakes allowed us to effectively observe nesting redbreast sunfish Lepomis auritus in a highly regulated river. Substrate stakes, which were constructed for the specific substratum complex (i.e., sand, gravel, and cobble) identified at our study site, were able to withstand a discharge level of approximately 300 m 3 /s and allowed us to simultaneously record 10 active nests before and during water releases from the dam. We believe our technique will be valuable for other researchers that work in regulated rivers to quantify behavior of aquatic fauna in response to a discharge disturbance.

Alabama↗

Summary of the Snake River plain Regional Aquifer-System Analysis in Idaho and eastern Oregon

Regional aquifers underlying the 15,600-square-mile Snake River Plain in southern Idaho and eastern Oregon was studied as part of the U.S. Geological Survey's Regional Aquifer-System Analysis program. The largest and most productive aquifers in the Snake River Plain are composed of Quaternary basalt of the Snake River Group, which underlies most of the 10,8000-square-mile eastern plain. Aquifer tests and simulation indicate that transmissivity of the upper 200 feet of the basalt aquifer in the eastern plain commonly ranges from about 100,000 to 1,000,000 feet squared per day. However, transmissivity of the total aquifer thickness may be as much as 10 million feet squared per day. Specific yield of the upper 200 feet of the aquifer ranges from about 0.01 to 0.20. Average horizontal hydraulic conductivity of the upper 200 feet of the basalt aquifer ranges from less than 100 to 9,000 feet per day. Values may be one to several orders of magnitude higher in parts in individual flows, such as flow tops. Vertical hydraulic conductivity is probably several orders of magnitude lower than horizontal hydraulic conductivity and is generally related to the number of joints. Pillow lava in ancestral Snake River channels has the highest hydraulic conductivity of all rock types. Hydraulic conductivity of the basalt decreases with depth because of secondary filling of voids with calcite and silica. An estimated 80 to 120 million acre-feet of water is believed to be stored in the upper 200 feet of the basalt aquifer in the eastern plain. The most productive aquifers in the 4,800-square-mile western plain are alluvial sand and gravel in the Boise River valley. Although aquifer tests indicate that transmissivity of alluvium in the Boise River valley ranges from 5,000 to 160,000 feet squared per day, simulation suggests that average transmissivity of the upper 500 feet is generally less than 20,000 feet squared per day. Vertically averaged horizontal hydraulic conductivity of the upper 500 feet of alluvium ranges from about 4 to 40 feet per day; higher values can be expected in individual sand and gravel zones. Vertical hydraulic conductivity is considerably lower because of the presence of clay layers. Hydraulic heads measured in piezometers, interpreted from diagrams showing ground-water flow and equipotential lines and estimated by computer simulation, demonstrate that water movement is three dimensional through the rock framework. Natural recharge takes place along the margins of the plain where head decreases with depth; discharge takes place near some reaches of the Snake River and the Boise River where head increases with depth. Geothermal water in rhyolitic rocks in the western plain and western part of the eastern plain has higher hydraulic head than the overlying cold water. Geothermal water, therefore, moves upward and merges into the cold-water system. Basin water-budget analyses indicate that the volume of cold water. Carbon-14 age determinations, which indicate that residence time of geothermal water is 17,700 to 20,300 years, plus or minus 4,000 years, imply slow movement of water through the geothermal system. Along much of its length, the Snake River gains large quantities of ground water. On the eastern plain, the river gained about 1.9 million acre-feet of water between Blackfoot and Neeley, Idaho, in 1980. Between Milner and King Hill, Idaho, the river gained 4.7 million acre-feet, mostly as spring flow from the north side. Upstream from Blackfoot and in the vicinity of Lake Walcott, the rover loses flow to ground water during parts or all of the year. On the western plain, river gains from ground water are small relative to those on the eastern plain; most are from seepage. Streams in tributary drainage basins supply calcium/bicarbonate type and calcium/magnesium/bicarbonate type water to the plain. Water type is a reflection of the chemical composition of rocks in the drainage basin, Concentrations of dissolved solids are smallest, about 50 milligrams per liter, in streams such as the Boise River that drain areas of granitic rocks; concentrations are greatest, about 400 milligrams per liter, in streams such as the Owyhee and Raft Rivers that drain area of sedimentary rocks. Water chemistry reflects the interaction of surface water and ground water. The chemical composition of ground water in the plain is essentially the same as that in streamflow and groundwater discharge from tributary drainage basins. Tributary drainage basins supplied 85 percent of the ground-water recharge in the eastern plain during 1980 and a nearly equivalent percentage of the solute load in ground water; human activities and dissolution of minerals supplied the other solutes. Dissolved-solids concentrations in ground water were generally less than 400 milligrams per liter. Water from the lower geothermal system is chemically different from water from the upper cold-water system. Geothermal water typically has greater concentrations of sodium, bicarbonate, sulfate, chloride, fluoride, silica, arsenic, boron, and lithium and smaller concentrations of calcium, magnesium, and hydrogen. Difference are attributed to ion exchange as geothermal moves through the rock framework. Irrigation, mostly on the Snake River Plain, accounted for about 96 percent of consumptive water use in Idaho during 1980. The use of surface water for irrigation for more than 100 years has caused major changes in the hydrologic system on the plain. Construction of dams, reservoirs, and diversifications effected planned changes in the surface-water system but resulted in largely unplanned changes in the ground-water system. During those years of irrigation, annual recharge in the main part of the eastern plain increased to about 6.7 million acre-feet in 1980, or by about 70 percent. Most of the increase was from percolation of surface water diverted for irrigation. From preirrigation to 1952, groundwater storage increased about 24 million acre-feet, and storage decreased from 1952 to 1964 and from 1976 to 1980 because of below-normal precipitation and increased withdrawals of ground water for irrigation. Annual ground-water discharge increased to about 7.1 million acre-feet in 1980, or about 80 percent since the start of irrigation. About 10 percent of the 1980 total discharge was ground-water pumpage. About 3.1 million acres, or almost one-third of the plain, was irrigated during 1980: 2.0 million acres with surface water, 1.0 million acres with ground water, and 0.1 million acres with combined surface and ground water. About 8.9 million acre-feet of Snake River water was diverted for irrigation during 1980 and 2.3 million acre-feet of ground water was pumped from 5,300 wells. Most irrigation wells on the eastern plain are open to basalt. About two-thirds of them yield more than 1,500 gallons per minute with a reported maximum of 7,240 gallons per minute; drawdown is less than 20 feet in two-thirds of the wells. Most irrigation wells on the western plain are open to sedimentary rocks. About one-third of them yield more than 1,00 gallons per minute with a reported maximum of 3,850 gallons per minute; drawndown is less than 20 feet in about one-fifth of the wells. The major instream use of water on the Snake River Plain is hydroelectric power generation. Fifty-two million acre-feet of water generated 2.6 million megawatthours of electricity during 1980. Digital computer ground-water flows models of the eastern and western plain reasonably simulated regional changes in water levels and ground-water discharges from 1880 (preirrigation) to 1980. Model results support the concept of three-dimensional flow and the hypotheses of no underflow between the eastern and western plain. Simulation of the regional aquifer system in the eastern plain indicates that is 1980 hydrologic conditions, including pumpage, were to remain the same for another 30 years, moderate declines in ground-water levels and decreases in spring discharges would continue. Increased ground-water pumpage to irrigate an additional 1 million acres could cause ground-water levels to decline a few tens of feet in the central part of the plain and could cause corresponding decreases in ground-water discharge. A combination of actions such as increased ground-water pumpage and decreased use of surface water for irrigation (resulting in reduced recharge) would accentuate the changes.

Idaho;Oregon↗

Areas contributing recharge to production wells and effects of climate change on the groundwater system in the Chipuxet River and Chickasheen Brook Basins, Rhode Island

The Chipuxet River and Chickasheen Brook Basins in southern Rhode Island are an important water resource for public and domestic supply, irrigation, recreation, and aquatic habitat. The U.S. Geological Survey, in cooperation with the Rhode Island Department of Health, began a study in 2012 as part of an effort to protect the source of water to six large-capacity production wells that supply drinking water and to increase understanding of how climate change might affect the water resources in the basins. Soil-water-balance and groundwater-flow models were developed to delineate the areas contributing recharge to the wells and to quantify the hydrologic response to climate change. Surficial deposits of glacial origin ranging from a few feet to more than 200 feet thick overlie bedrock in the 24.4-square mile study area. These deposits comprise a complex and productive aquifer system. Simulated areas contributing recharge to the production wells covered a total area of 0.63 square miles for average well withdrawal rates from 2007 through 2011 (total rate of 583 gallons per minute). Simulated areas contributing recharge for the maximum well pumping capacities (total rate of 3,700 gallons per minute) covered a total area of 2.55 square miles. Most simulated areas contributing recharge extend upgradient of the wells to morainal and upland till deposits and to groundwater divides. Some simulated areas contributing recharge include small, isolated areas remote from the wells. Relatively short groundwater traveltimes from recharging locations to discharging wells indicated that the wells are vulnerable to contamination from land-surface activities; median traveltimes ranged from 3.5 to 8.6 years for the production wells examined, and 57 to 91 percent of the traveltimes were 10 years or less. Land cover in the areas contributing recharge includes a substantial amount of urban and agriculture land use for five wells adjacent to the Chipuxet River; for one well adjacent to a tributary stream, land use is less developed. The calibrated groundwater-flow model provided a single, best representation of the areas contributing recharge to a production well. The parameter variance-covariance matrix from model calibration was used to create parameter sets that reflect the uncertainty of the parameter estimates and the correlation among parameters to evaluate the uncertainty associated with the predicted contributing areas to the wells. A Monte Carlo analysis led to contributing areas expressed as a probability distribution that differed from a single deterministic contributing area. Because of the effects of parameter uncertainty, the size of the probabilistic contributing areas for both average and maximum pumping rates was larger than the size of the deterministic contributing areas for the wells. Thus, some areas not in the deterministic contributing area might actually be in the contributing area, including additional areas of urban and agricultural land use that has the potential to contaminate groundwater. Additional areas that might be in the contributing area included recharge originating near the pumping wells that have relatively short groundwater-flow paths and traveltimes. At the maximum pumping rates, areas associated with low probabilities extended long distances along groundwater divides in the uplands remote from the wells. Climate projections for the Chipuxet River and Chickasheen Brook Basins from downscaled output from general circulation models indicate that mean annual temperature might increase by 4.7 degrees Fahrenheit and 8.0 degrees Fahrenheit by the late 21st century (2070–99) compared with the late 20th century (1970–99) under scenarios of lower and higher emissions of greenhouse gases, respectively. By the late 21st century, winter and spring precipitation is projected to increase by 12 to 17 percent, summer precipitation to increase by about the same as mean annual precipitation (8 percent), and fall precipitation to decrease by 5 percent for both emission scenarios compared with the late 20th century. Soil-water-balance simulations indicate that, although precipitation is expected to increase in three seasons, only in winter do precipitation increases exceed actual evapotranspiration increases. Recharge is projected to decrease in fall and generally change little in spring and summer. By the late 21st century, winter recharge is expected to increase by 13 percent for the lower emissions scenario and by 15 percent for the higher emissions scenario. In fall, recharge is projected to diminish by 13 percent for the lower emissions scenario and by 24 percent for the higher emissions scenario. Although recharge is projected to change seasonally in the 21st century, mean annual recharge changes minimally. Soil moisture is projected to decrease in the 21st century from spring through fall because of increases in potential evapotranspiration, and in fall because of decreases in precipitation in addition to increases in potential evapotranspiration. By the late 21st century, soil moisture for the lower emissions scenario is expected to decrease by 11 percent in summer and 15 percent in fall, and for the higher emissions scenario, decrease by 23 percent for both seasons. These decreases in soil moisture during the growing season might have implications for agriculture in the study area. Predicted changes in the magnitude and seasonal distribution of recharge in the 21st century increase simulated base flows and groundwater levels in the winter months for both emission scenarios, but because of less recharge in the fall and less or about the same recharge in the preceding months of spring and summer, base flows and groundwater levels in the fall months decrease for both emission scenarios. October has the largest base flow and groundwater level decreases. By the late 21st century, base flows at the Chipuxet River in October are projected to decrease by 9 percent for the lower emissions scenario and 18 percent for the higher emissions scenario. For a headwater stream in the upland till with shorter groundwater-flow paths and lower storage properties in its drainage area, base flows in October are projected to diminish by 28 percent and 42 percent for the lower and higher emissions scenarios by the late 21st century. Groundwater level changes in the uplands show substantial decreases in fall, but because of the large storage capacity of stratified deposits, water levels change minimally in the valley. By the late 21st century, water levels in large areas of upland till deposits in October are projected to decrease by up to 2 feet for the lower emissions scenario, whereas large areas decrease by up to 5 feet, with small areas with decreases of as much as 10 feet, for the higher emissions scenario. For both emission scenarios, additional areas of till go dry in fall compared with the late 20th century. Thus projected changes in recharge in the 21st century might extend low flows and low water levels for the year later in fall and there might be more intermittent headwater streams compared with the late 20th century with corresponding implications to aquatic habitat. Finally, the size and location of the simulated areas contributing recharge to the production wells are minimally affected by climate change because mean annual recharge, which is used to determine the contributing areas to the production wells, is projected to change little in the 21st century.

Rhode Island↗

Decision Support System for Evaluation of Gunnison River Flow Regimes With Respect To Resources of the Black Canyon of the Gunnison National Park

This report describes and documents a decision support system for the Gunnison River in Black Canyon of the Gunnison National Park. It is a macro-embedded EXCEL program that calculates and displays indicators representing valued characteristics or processes in the Black Canyon based on daily flows of the Gunnison River. The program is designed to easily accept input from downloaded stream gage records or output from the RIVERWARE reservoir operations model being used for the upstream Aspinall Unit. The decision support system is structured to compare as many as eight alternative flow regimes, where each alternative is represented by a daily sequence of at least 20 calendar years of streamflow. Indicators include selected flow statistics, riparian plant community distribution, clearing of box elder by inundation and scour, several measures of sediment mobilization, trout fry habitat, and federal reserved water rights. Calculation of variables representing National Park Service federal reserved water rights requires additional secondary input files pertaining to forecast and actual basin inflows and storage levels in Blue Mesa reservoir. Example input files representing a range of situations including historical, reconstructed natural, and simulated alternative reservoir operations are provided with the software.

Open-File Report↗

Hydrogeologic framework of the uppermost principal aquifer systems in the Williston and Powder River structural basins, United States and Canada

The glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston and Powder River structural basins within the United States and Canada are the uppermost principal aquifer systems and most accessible sources of groundwater for these energy-producing basins. The glacial aquifer system covers the northeastern part of the Williston structural basin. The lower Tertiary and Upper Cretaceous aquifer systems are present in about 91,300 square miles (mi 2 ) of the Williston structural basin and about 25,500 mi 2 of the Powder River structural basin. Directly under these aquifer systems are 800 to more than 3,000 feet (ft) of relatively impermeable marine shale that serves as a basal confining unit. The aquifer systems in the Williston structural basin have a shallow (less than 2,900 ft deep), wide, and generally symmetrical bowl shape. The aquifer systems in the Powder River structural basin have a very deep (as much as 8,500 ft deep), narrow, and asymmetrical shape. The Williston structural basin has been an important oil and natural gas producing region since the 1950s, and production has increased substantially since the mid-2000s due to improved drilling and hydraulic fracturing methods from deep formations, such as the Bakken and Three Forks Formations. These improved methods require considerable volumes of freshwater mostly from shallow aquifers or surface water. Coal, lignite, and coal-bed natural gas are additional sources of energy in both basins that can affect the quality and quantity of shallow aquifers through strip mining and groundwater depletion. In 2011, the U.S. Geological Survey initiated a regional study of the glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston and Powder River structural basins with the goal to quantify groundwater availability. This report, together with a companion report of the conceptual flow model, provides an improved understanding of the groundwater flow systems and a basis for a numerical, regional groundwater-flow model. This study combines the lithostratigraphic units of the glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the United States and Canada into 7 regional hydrogeologic units—glacial deposits, 4 bedrock aquifers, and 2 bedrock confining units—using general hydraulic properties. The glacial deposits are composed of till and glacial outwash sands and gravels with areas of cobbles and boulders. The four bedrock aquifers are the upper Fort Union, lower Fort Union, lower Hell Creek, and Fox Hills aquifers and are contained primarily in sandstone layers. The two confining units are the middle Fort Union hydrogeologic unit (shale) and upper Hell Creek hydrogeologic unit (contains less sandstone than the underlying lower Hell Creek aquifer). Water from hydrogeologic units in these three aquifer systems is relatively fresh and potable, whereas withdrawals seldom occur from units below the basal confining unit because of great depths (greater than 800 ft) and poor water quality. Analysis of about 300 electric (resistivity) and lithologic logs in the Williston structural basin and numerous existing publications for the Powder River structural basin were used to develop a three-dimensional hydrogeologic framework for both basins. Interpolated thicknesses of the glacial deposits, the lower Tertiary aquifer system, and the Upper Cretaceous aquifer system in the Williston structural basin are less than about 750; 2,250; and 1,050 ft, respectively. Interpolated thicknesses of the lower Tertiary aquifer system and the Upper Cretaceous aquifer system in the Powder River structural basin are less than about 7,180 and 5,070 ft, respectively. Interpolated horizontal hydraulic conductivity values for the Williston structural basin were as much as 25 feet per day (ft/d) in the glacial deposits and had smaller ranges in the lower Tertiary aquifer system (0.01–9.8 ft/d) and in the Upper Cretaceous aquifer system (0.06–5.5 ft/d). In the Powder River structural basin, the lower Tertiary aquifer system had a greater range of interpolated horizontal hydraulic conductivity values (0.10–11 ft/d) than the Upper Cretaceous aquifer system (0.02–5.7 ft/d). Transmissivity is greatest in the gravel zones of the glacial deposits (2,120 feet squared per day) and generally decreases with depth into the bedrock units. Regionally, water in the lower Tertiary and Upper Cretaceous aquifer systems flows in a northerly or northeasterly direction from the Powder River structural basin to the Williston structural basin. Groundwater flow in the Williston structural basin generally is easterly or northeasterly. Flow in the uppermost hydrogeologic units generally is more local and controlled by topography where unglaciated in the Williston structural basin than is flow in the glaciated part and in underlying aquifers. Groundwater flow in the Powder River structural basin generally is northerly with local variations greatest in the uppermost aquifers. Groundwater is confined, and flow is regional in the underlying aquifers.

Powder River Basin;Williston Basin↗

Hood River PIT-tag interrogation system efficiency study. Annual report of U.S. Geological Survey activities: November 2010-October 2011

Introduction During summer 2010, an agreement was made between the US Geological SurveyColumbia River Research Laboratory (USGS-CRRL) and the Confederated Tribes of the Warm Springs (CTWS) to operate an experimental Passive Integrated Transponder (PIT)-tag interrogation system (PTIS) near the mouth of the Hood River for a year and provide fishdetection efficiency estimates (Bonneville Power Administration (BPA) project number 1988- 053-03, contract number 50150). A previous agreement between Oregon Department of Fish and Wildlife (ODFW) and USGS-CRRL had funded materials acquisition, construction, and installation of the PTIS (BPA project number 1988-053-04, contract number 48684). The primary purpose of the project was to test the efficacy of a PTIS in the lower Hood River for providing data on returning adult salmonids to the Hood River as part of the Hood River Production Monitor and Evaluation project (HRPME). Because PIT tags are small, relatively inexpensive, carry no internal battery, and last through the lifespan of most fishes, they are commonly used in long term fish monitoring projects. They have been extensively used in the Columbia River basin to monitor salmonid behavior and survival through life stages and migration routes in the mainstem Columbia River (Skalski et al. 1998; Zabel and Achord 2004). Increasingly, PIT-tag detection equipment has been deployed in streams to investigate salmonid behavior (Zydlewski et al. 2001, 2006; Riley et al. 2003; Bond et al. 2007). Most of the detection systems deployed and evaluated to date have been in much smaller streams than the mainstem of the Hood River (Zydlewski et al. 2001, 2006; Bond et al. 2007; Horton et al. 2007; Connolly et al. 2008), but researchers are attempting to expand detection abilities to larger streams and rivers. Large streams and rivers can prove extremely challenging to monitor. Some systems have showed promise for contributing valuable detection data, others have proved less successful. A detection system in the Klamath River (Beeman et al. 2012), a site similar in size to the Hood River, suffered problems from cables being dislodged and high water that resulted in a detection efficiency estimate for juvenile coho salmon of less than 0.05. An additional USGS-CRRL task, under contract number 50150, was to build three antennas for use with Destron-Fearing 2001F-ISO PIT tag readers. These antennas would be 5 used at the East Fork Hood River Acclimation site. They would be placed in the outflow channel to inform managers about the number of PIT tagged steelhead smolts released to the Hood River after a period of acclimation when some mortality and predation might occur.

Oregon↗

Rivers are social–ecological systems: Time to integrate human dimensions into riverscape ecology and management

Incorporation of concepts from landscape ecology into understanding and managing riverine ecosystems has become widely known as riverscape ecology. Riverscape ecology emphasizes interactions among processes at different scales and their consequences for valued ecosystem components, such as riverine fishes. Past studies have focused strongly on understanding the ecological processes in riverscapes and how human actions modify those processes. It is increasingly clear, however, that an understanding of the drivers behind actions that lead to human modification also merit consideration, especially regarding how those drivers influence management efficacy. These indirect drivers of riverscape outcomes can be understood in the context of a diverse array of social processes, which we collectively refer to as human dimensions. Like ecological phenomena, social processes also exhibit complex interactions across spatiotemporal scales. Greater emphasis on feedbacks between social and ecological processes will lead scientists and managers to more completely understand riverscapes as complex, dynamic, interacting social–ecological systems. Emerging applications in riverscapes, as well as studies of other ecosystems, provide examples that can lead to stronger integration of social and ecological science. We argue that conservation successes within riverscapes may not come from better ecological science, improved ecosystem service analyses, or even economic incentives if the fundamental drivers of human behaviors are not understood and addressed in conservation planning and implementation.

WIREs Water↗

Movements of adult chinook salmon during spawning migration in a metals-contaminated system, Coeur d'Alene River, Idaho

Spawning migration of adult male chinook salmon Oncorhynchus tshawytscha was monitored by radio telemetry to determine their response to the presence of metals contamination in the South Fork of the Coeur d'Alene River, Idaho. The North Fork of the Coeur d'Alene River is relatively free of metals contamination and was used as a control. In all, 45 chinook salmon were transported from their natal stream, Wolf Lodge Creek, tagged with radio transmitters, and released in the Coeur d'Alene River 2 km downstream of the confluence of the South Fork and the North Fork of the Coeur d'Alene River. Fixed telemetry receivers were used to monitor the upstream movement of the tagged chinook salmon through the confluence area for 3 weeks after release. During this period, general water quality and metals concentrations were monitored in the study area. Of the 23 chinook salmon observed to move upstream from the release site and through the confluence area, the majority (16 fish, 70%) moved up the North Fork, and only 7 fish (30%) moved up the South Fork, where greater metals concentrations were observed. Our results agree with laboratory findings and suggest that natural fish populations will avoid tributaries with high metals contamination.

Transactions of the American Fisheries Society↗

Simulated Water-Management Alternatives Using the Modular Modeling System for the Methow River Basin, Washington

A precipitation-runoff model for the Methow River Basin was used to simulate six alternatives: (1) baseline of current flow, (2) line irrigation canals to limit seepage losses, (3) increase surface-water diversions through unlined canals for aquifer recharge, (4) convert from surface-water to ground-water resources to supply water for irrigation, and (5) reduce tree density in forested headwater catchments, and (6) natural flow. Daily streamflow from October 1, 1959, to September 30, 2001 (water years 1960?2001) was simulated. Lining irrigation canals (alternative 2) increased flows in the Chewuch, Twisp, and the Methow (upstream and at Twisp) Rivers during September because of lower diversion rates, but not in the Methow River near Pateros. Increasing diversions for aquifer recharge (alternative 3) increased streamflow from September into January, but reduced streamflow earlier in the summer. Conversion of surface-water diversions to ground-water wells (alternative 4) resulted in the largest increase in September streamflow of any alternative, but also marginally lower January flows (at most -8 percent in the 90-percent exceedence value). Forest-cover reduction (alternative 5) produced large increases in streamflow during high-flow periods in May and June and earlier onset of high flows and small increases in January streamflows. September streamflows were largely unaffected by alternative 5. Natural streamflow (alternative 6) was higher in September and lower in January than the baseline alternative.

Open-File Report↗

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

The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed hydrologic and hydraulic analyses to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago El Guineo Dam. The Lago El Guineo Dam is within the headwaters of the Río Grande de Manatí and impounds a drainage area of about 4.25 square kilometers. The hydrologic assessment was designed to determine the outflow hydrographs and peak discharges for Lago El Guineo and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation event, (2) a 24-hour probable maximum precipitation event, and (3) a 24-hour, 100-year recurrence rainfall event. The hydraulic study simulated a dam failure of Lago El Guineo Dam using flood hydrographs generated from the hydrologic study. The simulated dam failure generated a hydrograph that was routed downstream from Lago El Guineo Dam through the lower reaches of the Río Toro Negro and the Río Grande de Manatí to determine water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” conditions. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC–HMS) and Hydrologic Engineering Center’s River Analysis System (HEC–RAS) computer programs, developed by the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively. The flow routing in the hydraulic analyses was completed using the unsteady flow module available in the HEC–RAS model. Above the Lago El Guineo Dam, the simulated inflow peak discharges from HEC–HMS resulted in about 550 and 414 cubic meters per second for the 6- and 24-hour probable maximum precipitation events, respectively. The 24-hour, 100-year recurrence storm simulation resulted in a peak discharge of about 216 cubic meters per second. For the hydrologic analysis, no dam failure conditions are considered within the model. The results of the hydrologic simulations indicated that for all hydrologic conditions scenarios, the Lago El Guineo Dam would not experience overtopping. For the dam breach hydraulic analysis, failure by piping was the selected hypothetical failure mode for the Lago El Guineo Dam. Results from the simulated dam failure of the Lago El Guineo Dam using the HEC–RAS model for the 6- and 24-hour probable maximum precipitation events indicated peak discharges below the dam of 1,342.43 and 1,434.69 cubic meters per second, respectively. Dam failure during the 24-hour, 100-year recurrence rainfall event resulted in a peak discharge directly downstream from Lago El Guineo Dam of 1,183.12 cubic meters per second. Dam failure during sunny-day conditions (no precipitation) produced a peak discharge at Lago El Guineo Dam of 1,015.31 cubic meters per second assuming the initial water-surface elevation was at the morning-glory spillway invert elevation. The results of the hydraulic analysis indicate that the flood would extend to many inhabited areas along the stream banks from the Lago El Guineo Dam to the mouth of the Río Grande as a result of the simulated failure of the Lago El Guineo Dam. Low-lying regions in the vicinity of Ciales, Manatí, and Barceloneta, Puerto Rico, are among the regions that would be most affected by failure of the Lago El Guineo Dam. Effects of the flood control (levee) structure constructed in 2000 to provide protection to the low-lying populated areas of Barceloneta, Puerto Rico, were considered in the hydraulic analysis of dam failure. The results indicate that overtopping can be expected in the aforementioned levee during 6- and 24-hour probable maximum precipitation events. The levee was not overtopped during dam failure scenarios under the 24-hour, 100-year recurrence rainfall event or sunny-day conditions.

Orocovis↗