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At least 775 records · Page 43Linked to original sources

Ground-water basic data for Griggs and Steele Counties, North Dakota

The objectives of the hydrologic investigation in Griggs and Steele Counties, N. Dak. (fig. 1) were to: (1) determine the location, extent, and nature of the major aquifers; (2) evaluate the occurrence and movement of ground water, including recharge and discharge; (3) estimate the quantities of water stored in the aquifers; (4) estimate the potential yields of wells tapping the major aquifers; and (5) determine the chemical quality of the ground water.

North Dakota↗

Assessment of crop growth and soil water modules in SWAT2000 using extensive field experiment data in an irrigation district of the Yellow River Basin

SWAT, a physically-based, hydrological model simulates crop growth, soil water and groundwater movement, and transport of sediment and nutrients at both the process and watershed scales. While the different versions of SWAT have been widely used throughout the world for agricultural and water resources applications, little has been done to test the performance, variability, and transferability of the parameters in the crop growth, soil water, and groundwater modules in an integrated way with multiple sets of field experimental data at the process scale. Using an multiple years of field experimental data of winter wheat (Triticum aestivum L.) in the irrigation district of the Yellow River Basin, this paper assesses the performance of the plant-soil-groundwater modules and the variability and transferability of SWAT2000. Comparison of the simulated results by SWAT to the observations showed that SWAT performed quite unsatisfactorily in LAI predictions during the senescence stage, in yield predictions, and in soil-water estimation under dry soil-profile conditions. The unsatisfactory performance in LAI prediction might be attributed to over-simplified senescence modeling; in yield prediction to the improper computation of the harvest index; and in soil water under dry conditions to the exclusion of groundwater evaporation from the soil water balance in SWAT. In this paper, improvements in crop growth, soil water, and groundwater modules in SWAT were implemented. The saturated soil profile was coupled to the oscillating groundwater table. A variable evaporation coefficient taking into account soil water deficit index, groundwater depth, and crop root depth was used to replace the fixed coefficient in computing groundwater evaporation. The soil water balance included the groundwater evaporation. The modifications improved simulations of crop evapotranspiration and biomass as well as soil water dynamics under dry soil-profile conditions. The evaluation shows that the crop growth and soil water components of SWAT could be further refined to better simulate the hydrology of agricultural watersheds. ?? 2008 Elsevier B.V. All rights reserved.

Journal of Hydrology↗

Concentrations and loads of cadmium, zinc, and lead in the main stem Coeur d'Alene River, Idaho—March, June, September, and October 1999

The Remedial Investigation/Feasibility Study conducted by the U.S. Environmental Protection Agency within the Spokane River Basin of northern Idaho and eastern Washington included extensive data-collection activities in numerous studies to determine the nature and extent of trace-element contamination within the basin. The objective of this particular study was to improve our understanding of the effects of different river discharges and lake levels of Coeur d'Alene Lake on the transport of cadmium, zinc, and lead within the main stem Coeur d'Alene River. In particular, water-quality data and loads during a broad range of hydrologic conditions were examined to determine if the river channel, flood plain, and associated ground water along the main stem Coeur d'Alene River acted as sources or sinks of trace elements. Water-quality samples were collected at six riverine stations and one lake station along a 35-mile reach during March, June, September, and October of 1999. Samples were analyzed for whole-water recoverable, filtered (0.45 micrometer), and dissolved (0.01 micrometer) concentrations of cadmium, zinc, and lead. Concentrations and loads of cadmium and zinc measured during the four sampling trips were predominately in the filtered and dissolved fraction ,rather than particulate. The smallest concentrations were measured during the June sampling trip when flows were high and snowmelt runoff diluted riverine concentrations. Conversely, the largest concentrations were measured during the latter two sampling trips when flows were low because a larger proportion of the river's discharge was contributed by ground-water inflow. During each sampling trip, cadmium and zinc concentrations generally decreased in a downstream directioeven as discharge increased in a downstream direction. Spatial and temporal trends exhibited by lead concentrations and loads during the four sampling trips were different from those of cadmium and zinc because of the propensity for lead to adsorb to sediment particles. Whole-water recoverable lead concentrations and loads during the four sampling trips were predominantly in the particulate fraction, with filtered and dissolved concentrations and loads composing a much smaller proportion of the recoverable fraction compared to cadmium and zinc. Filtered lead concentrations generally increased at a faster rate in the downstream direction than dissolved lead concentrations; thus, colloidallead either was being formed by complexation reactions or being added by sediment erosion in the downstream direction.

Idaho↗

Hydrologic investigations and data-collection network in strippable coal-resource areas in northwestern New Mexico

This report presents hydrologic investigations and data collections conducted by the U.S. Geological Survey in the strippable coal areas of northwestern New Mexico. Streamflow, ground-water, and quality-of-water data were collected to provide information about baseline or prevailing hydrologic conditions. A network of hydrologic data-collection sites in the strippable coal areas of the Fruitland Formation was designed to meet the need of detailed investigations, including site-specific studies, and to provide hydrologic data in support of the expanding mining activity. The network consists of 34 continuous-record streamflow-gaging stations (32 included water-quality sampling), 20 miscellaneous water quality of streamflow stations, 12 annual maximum discharge stations, 27 observation wells completed in strata associated with the strippable coal seams, and 24 observation wells completed in channel alluvium downstream from strippable coal areas. (USGS)

Open-File Report↗

Chemical, geologic, and hydrologic data from the study of acidic contamination in the Miami Wash-Pinal Creek area, Arizona, water years 1984-87

Occurrence and movement of acidic contamination in the aquifer and streams of the Pinal Creek basin near Globe, Arizona, is the focus of an ongoing study by the U.S. Geological Survey. Groundwater data from that study for water years 1984 to 1987 include location, construction information, and site plans for six groups of monitoring wells, mineralogic and particle-size analyses of drill cuttings, water level measurements, and chemical analyses of water samples from 39 wells. Surface water data for 13 sites in this study include discharge measurements and chemical analysis of water and streambed sediment samples. Monthly discharge data are presented for one site. Monthly precipitation amounts and statistics of long-term precipitation are presented for two sites. (USGS)

Open-File Report↗

Operation of hydrologic data collection stations by the U.S. Geological Survey in 1985

The U.S. Geological Survey (USGS) operated hydrologic data collection stations during fiscal yr 1985 in response to the needs of all levels of Government for hydrologic information. Surface water discharge was determined at 11,076 stations; stage data on streams, reservoirs, and lakes were recorded at 2,141 stations; and surface water quality was determined at 4,166 stations. Groundwater levels were measured at 39,301 stations, and the quality of groundwater was determined at 9,263 stations nationwide. Data on sediment were collected daily at 212 stations and on a periodic basis at 1,027 stations. Information on precipitation quantity was collected at 921 stations, and the quality of precipitation was analyzed at 108 stations. Data collection platforms for satellite telemetry of hydrologic information were used at 1,520 USGS stations. Funding support for the hydrologic stations was derived either solely or from a combination of three major sources--the Geological Survey 's Federal Program appropriation, the Federal-State Cooperative Program, and reimbursements from other Federal agencies. (Author 's abstract)

Open-File Report↗

Tropical storm Irene flood of August 2011 in northwestern Massachusetts

A Presidential disaster was declared in northwestern Massachusetts, following flooding from tropical storm Irene on August 28, 2011. During the storm, 3 to 10 inches of rain fell on soils that were susceptible to flash flooding because of wet antecedent conditions. The gage height at one U.S. Geological Survey streamgage rose nearly 20 feet in less than 4 hours because of the combination of saturated soils and intense rainfall. On August 28, 2011, in the Deerfield and Hoosic River Basins in northwestern Massachusetts, new peaks of record were set at six of eight U.S. Geological Survey long-term streamgages with 46 to 100 years of record. Additionally, high-water marks were surveyed and indirect measurements of peak discharge were calculated at two discontinued streamgages in the Deerfield and Hoosic River Basins with 24 and 61 years of record, respectively. This data resulted in new historic peaks of record at the two discontinued streamgages from tropical storm Irene. Peak flows that resulted from tropical storm Irene (August 28, 2011) were determined at the U.S. Geological Survey streamgages by using stage-discharge rating curves and indirect computation methods. For six streamgages, indirect computation methods were used to compute the peak flows. Peak flows from tropical storm Irene had annual exceedance probabilities (AEPs) that ranged from 5.4 percent to less than 0.2 percent at 10 streamgages in northwestern Massachusetts. Discharges calculated for select AEPs as a part of this study were compared with discharges published for the same AEPs in the effective Federal Emergency Management Agency flood insurance studies (FISs) for communities in the study area. Discharges estimated for the 10-, 2-, 1-, and 0.2-percent AEPs at two streamgages on the main stem of the Deerfield River ranged from about 3 percent lower to 14 percent higher than discharges in the FISs. AEP discharges calculated for two streamgages on tributaries to the Deerfield River were 27 to 89 percent higher than the FISs. For the four streamgages in the Hoosic River Basin, the 10-, 2-, 1-, and 0.2-percent AEP discharges calculated ranged from about 33 percent lower to 5 percent higher than the FISs. The simulated 1-percent AEP discharge water-surface elevations (nonregulatory) from recent (2015–16) hydraulic models for river reaches in the study area, which include the Deerfield, Green, and North Rivers in the Deerfield River Basin and the Hoosic River in the Hoosic River Basin, were compared with water-surface profiles in the FISs. The water-surface elevation comparisons were generally done downstream and upstream from bridges, dams, and major tributaries. The simulated 1-percent AEP discharge water-surface elevations of the recent hydraulic studies averaged 2.2, 2.3, 0.3, and 0.7 ft higher than water-surface elevations in the FISs for the Deerfield, Green, North, and Hoosic Rivers, respectively. The differences in water-surface elevations between the recent (2015–16) hydraulic studies and the FISs likely are because of (1) improved land elevation data from light detection and ranging (lidar) data collected in 2012, (2) detailed surveying of hydraulic structures and cross sections throughout the river reaches in 2012–13 (reflecting structure and cross section changes during the last 30–35 years), (3) updated hydrology analyses (30–35 water years of additional peak flow data at streamgages), and (4) high-water marks from the 2011 tropical storm Irene flood being used for model calibration.

Massachusetts↗

Water resources of Monroe County, New York, water years 2003-08: Streamflow, constituent loads, and trends in water quality

This report, the sixth in a series published since 1994, presents analyses of hydrologic data in Monroe County for the period October 2002 through September 2008. Streamflows and water quality were monitored at nine sites by the Monroe County Department of Health and the U.S. Geological Survey. Streamflow yields (flow per unit area) were highest in Northrup Creek, which had sustained flows from year-round inflow from the village of Spencerport wastewater-treatment plant and seasonal releases from the New York State Erie (Barge) Canal. Genesee River streamflow yields also were high, at least in part, as a result of higher rainfall and lower evapotranspiration rates in the upper part of the Genesee River Basin than in the other study basins. The lowest streamflow yields were measured in Honeoye Creek, which reflected a decrease in flows due to the withdrawals from Hemlock and Canadice Lakes for the city of Rochester water supply. Water samples collected at nine monitoring sites were analyzed for nutrients, chloride, sulfate, and total suspended solids. The loads of constituents, which were computed from the concentration data and the daily flows recorded at each of the monitoring sites, are estimates of the mass of the constituents that was transported in the streamflow. Annual yields (loads per unit area) also were computed to assess differences in constituent transport among the study basins. All urban sites - Allen Creek and the two downstream sites on Irondequoit Creek - had seasonally high concentrations and annual yields of chloride. Chloride loads are attributed to the application of road-deicing salts to the county's roadways and are related to population and road densities. The less-urbanized sites in the study - Genesee River, Honeoye Creek, and Oatka Creek - had relatively low concentrations and yields of chloride. The highest concentrations and yields of sulfate were measured in Black Creek, Oatka Creek, and Irondequoit Creek at Railroad Mills and are attributable to dissolution of sulfate from gypsum (calcium sulfate) deposits in Silurian shale bedrock that crops out upstream from these monitoring sites. Northrup Creek had the highest concentrations of phosphorus, orthophosphate, and nitrogen, and high yields of nitrate plus nitrite nitrogen and ammonia plus organic nitrogen. These results are attributed to discharges from the Spencerport wastewater-treatment plant (which ceased operation in June 2008), diversions from the New York State Erie (Barge) Canal, and manure and fertilizers applied to agricultural fields. Concentrations and yields of nitrate plus nitrite nitrogen also were high in Oatka Creek and Black Creek; basins with substantial agricultural land uses. Allen Creek had the second highest yield of ammonia plus organic nitrogen. Honeoye Creek, which drains a relatively undeveloped basin, had the lowest yields of nitrogen constituents. The second highest median concentrations and highest sample concentrations of phosphorus and orthophosphate, as well as the highest phosphorus yields, were measured in the Genesee River. A comparison of the yields computed for the two downstream sites on Irondequoit Creek - above Blossom Road and at Empire Boulevard - permitted an assessment of the mitigative effects of the Ellison Park wetland on constituent loads, which would otherwise be transported to Irondequoit Bay. These effects also include those provided by a flow-control structure (installed mid-way through the wetland during February 1997), which was designed to increase the dispersal and short-term detention of stormflows in the wetland. The wetland decreased yields of particulate constituents - phosphorus and ammonia plus organic nitrogen - but had little effect on the yields of dissolved constituents - chloride, sulfate, and nitrate plus nitrite nitrogen. Trends in flow-adjusted concentrations were identified at all sites for most of the nutrient constituents that were evaluated. All of the linear time tren

Scientific Investigations Report↗

Hydrologic reconnaissance of Skull Valley, Tooele County, Utah

This report is the second in a series by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights, which describes the water resources of the western basins of Utah. Its purpose is to present available hydrologic data on Skull Valley, to provide an evaluation of the potential water-resource development of the valley, and to identify needed studies that would help provide an understanding of the valley's water supply.

Utah↗

Hydrologic reconnaissance of Rush Valley, Tooele County, Utah

This report is the third in a series by the U. S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights, which describes the water resources of the western basins of Utah. Its purpose is to present available hydrologic data for Rush Valley, to provide an evaluation of the potential water-resources development of the valley, and to identify needed studies that would help provide an understanding of the valley's water supply.

Utah↗

Simulation of streamflow and sediment transport in two surface-coal-mined basins in Fayette County, Pennsylvania

The Hydrological Simulation Program - Fortran (HSPF) was used to simulate streamflow and sediment transport in two surface-mined basins of Fayette County, Pa. Hydrologic data from the Stony Fork Basin (0.93 square miles) was used to calibrate HSPF parameters. The calibrated parameters were applied to an HSPF model of the Poplar Run Basin (8.83 square miles) to evaluate the transfer value of model parameters. The results of this investigation provide information to the Pennsylvania Department of Environmental Resources, Bureau of Mining and Reclamation, regarding the value of the simulated hydrologic data for use in cumulative hydrologic-impact assessments of surface-mined basins. The calibration period was October 1, 1985, through September 30, 1988 (water years 1986-88). The simulated data were representative of the observed data from the Stony Fork Basin. Mean simulated streamflow was 1.64 cubic feet per second compared to measured streamflow of 1.58 cubic feet per second for the 3-year period. The difference between the observed and simulated peak stormflow ranged from 4.0 to 59.7 percent for 12 storms. The simulated sediment load for the 1987 water year was 127.14 tons (0.21 ton per acre), which compares to a measured sediment load of 147.09 tons (0.25 ton per acre). The total simulated suspended-sediment load for the 3-year period was 538.2 tons (0.30 ton per acre per year), which compares to a measured sediment load of 467.61 tons (0.26 ton per acre per year). The model was verified by comparing observed and simulated data from October 1, 1988, through September 30, 1989. The results obtained were comparable to those from the calibration period. The simulated mean daily discharge was representative of the range of data observed from the basin and of the frequency with which specific discharges were equalled or exceeded. The calibrated and verified parameters from the Stony Fork model were applied to an HSPF model of the Poplar Run Basin. The two basins are in a similar physical setting. Data from October 1, 1987, through September 30, 1989, were used to evaluate the Poplar Run model. In general, the results from the Poplar Run model were comparable to those obtained from the Stony Fork model. The difference between observed and simulated total streamflow was 1.1 percent for the 2-year period. The mean annual streamflow simulated by the Poplar Run model was 18.3 cubic feet per second. This compares to an observed streamflow of 18.15 cubic feet per second. For the 2-year period, the simulated sediment load was 2,754 tons (0.24 ton per acre per year), which compares to a measured sediment load of 3,051.2 tons (0.27 ton per acre per year) for the Poplar Run Basin. Cumulative frequency-distribution curves of the observed and simulated streamflow compared well. The comparison between observed and simulated data improved as the time span increased. Simulated annual means and totals were more representative of the observed data than hourly data used in comparing storm events. The structure and organization of the HSPF model facilitated the simulation of a wide range of hydrologic processes. The simulation results from this investigation indicate that model parameters may be transferred to ungaged basins to generate representative hydrologic data through modeling techniques.

Pennsylvania↗

Reconnaissance examination of the biology, chemistry, and physical characteristics of selected streams in California and Nevada

This report contains hydrological data from several California and Nevada streams. Emphasis is placed upon water-quality data, but stream discharge at the time of making the water-quality measurements also is given. The purpose of the report is to provide personnel of the U.S. Bureau of Land Management with baseline hydrological data from the selected streams and one well. The streams, the stream sites selected for sampling, and the parameters measured, were chosen in consultation with U.S. Bureau of Land Management personnel.

California, Nevada↗

Effects of historical coal mining and drainage from abandoned mines on streamflow and water quality in Bear Creek, Dauphin County, Pennsylvania — March 1999–December 2002

More than 100 years of anthracite coal mining has changed surface- and ground-water hydrology and contaminated streams draining the Southern Anthracite Coal Field in east-central Pennsylvania. Bear Creek drains the western prong of the Southern Anthracite Coal Field and is affected by metals in drainage from abandoned mines and streamwater losses. Total Maximum Daily Loads (TMDL) developed for dissolved iron of about 5 lb/d (pounds per day) commonly are exceeded in the reach downstream of mine discharges. Restoration of Bear Creek using aerobic ponds to passively remove iron in abandoned mine drainage is under consideration (2004) by the Dauphin County Conservation District. This report, prepared in cooperation with the Dauphin County Conservation District, evaluates chemical and hydrologic data collected in Bear Creek and its receiving waters prior to implementation of mine-drainage treatment. The data collected represent the type of baseline information needed for documentation of water-quality changes following passive treatment of mine drainage in Pennsylvania and in other similar hydrogeologic settings. Seven surface-water sites on Bear Creek and two mine discharges were monitored for nearly three years to characterize the chemistry and hydrology of the following: (1) Bear Creek upstream of the mine discharges (BC-UMD), (2) water draining from the Lykens-Williamstown Mine Pool at the Lykens Water-Level Tunnel (LWLT) and Lykens Drift (LD) discharges, (3) Bear Creek after mixing with the mine discharges (BC-DMD), and (4) Bear Creek prior to mixing with Wiconisco Creek (BCM). Two sites on Wiconisco Creek, upstream and downstream of Bear Creek (WC-UBC and WC-DBC, respectively), were selected to evaluate changes in streamflow and water quality upon mixing with Bear Creek. During periods of below-normal precipitation, streamwater loss was commonly 100 percent upstream of site BC-UMD (streamflow range = 0 to 9.7 ft3/s (cubic feet per second)) but no loss was detected downstream owing to sustained mine water drainage from the Lykens Water-Level Tunnel (range = 0.41 to 3.7 ft3/s), Lykens Drift (range = 0.40 to 6.1 ft3/s), and diffuse zones of seepage. Collectively, mine water inputs contributed about 84 percent of base flow and 53 percent of stormflow measured in the downstream reach. An option under consideration by the Dauphin County Conservation District for treatment of the discharge from the LWLT requires the source of the discharge to be captured and rerouted downstream, bypassing approximately 1,000 feet of stream channel. Because streamwater loss upstream of the tunnel was commonly 100 percent, rerouting the discharge from the LWLT may extend the reach of Bear Creek that is subject to dryness. Differences in the chemistry of water discharging from the LWLT compared to the LD suggest that the flow path through the Lykens-Williamstown Mine Pool to each mine discharge is unique. The LWLT is marginally alkaline (median net acid neutralizing capacity (ANC) = 9 mg/L (milligrams per liter) as CaCO3; median pH = 5.9), commonly becomes acidic (minimum net ANC = -74 mg/L as CaCO3) at low flow, and may benefit from alkaline amendments prior to passive treatment. Water discharging from the LD provides excess ANC (median net ANC = 123 mg/L as CaCO3; median pH = 6.5) to the downstream reach and is nearly anoxic at its source (median dissolved oxygen = 0.5 mg/L). Low dissolved oxygen water with relatively high ANC and metals concentrations discharging from the LD is characteristic of a deeper flow path and longer residence time within the mine pool than the more acidic, oxygenated water discharging from the LWLT. TMDLs for iron have been developed for dissolved species only. Consequently, distinguishing between dissolved and suspended iron in Bear Creek is important for evaluating water-quality improvement through TMDL attainment. Median total iron concentration increased from 550 mg/L (micrograms per liter) at site BC-UM

Pennsylvania↗

Potentiometric surface in the Central Oklahoma (Garber-Wellington) aquifer, Oklahoma, 2009

A study of the hydrogeology of the Central Oklahoma aquifer was started in 2008 to provide the Oklahoma Water Resources Board (OWRB) hydrogeologic data and a groundwater flow model that can be used as a tool to help manage the aquifer. The 1973 Oklahoma water law requires the OWRB to do hydrologic investigations of Oklahoma's aquifers (termed 'groundwater basins') and to determine amounts of water that may be withdrawn by permitted water users. 'Maximum annual yield' is a term used by OWRB to describe the total amount of water that can be withdrawn from a specific aquifer in any year while allowing a minimum 20-year life of the basin (Oklahoma Water Resources Board, 2010). Currently (2010), the maximum annual yield has not been determined for the Central Oklahoma aquifer. Until the maximum annual yield determination is made, water users are issued a temporary permit by the OWRB for 2 acre-feet/acre per year. The objective of the study, in cooperation with the Oklahoma Water Resources Board, was to study the hydrogeology of the Central Oklahoma aquifer to provide information that will enable the OWRB to determine the maximum annual yield of the aquifer based on different proposed management plans. Groundwater flow models are typically used by the OWRB as a tool to help determine the maximum annual yield. This report presents the potentiometric surface of the Central Oklahoma aquifer based on water-level data collected in 2009 as part of the current (2010) hydrologic study. The U.S. Geological Survey (USGS) Hydrologic Investigations Atlas HA-724 by Christenson and others (1992) presents the 1986-87 potentiometric-surface map. This 1986-87 potentiometric-surface map was made as part of the USGS National Water-Quality Assessment pilot project for the Central Oklahoma aquifer that examined the geochemical and hydrogeological processes operating in the aquifer. An attempt was made to obtain water-level measurements for the 2009 potentiometric-surface map from the wells used for the 1986-87 potentiometric-surface map. Well symbols with circles on the 2009 potentiometric-surface map (fig. 1) indicate wells that were used for the 1986-87 potentiometric-surface map.

Scientific Investigations Map↗

Surface-water hydrology of the Western New York Nuclear Service Center Cattaraugus County, New York

Precipitation data were collected from October 1980 through September 1983 from three recording gages at the Western New York Nuclear Service Center, and surface water data were collected at three continuous-record gaging stations and one partial-record gage on streams that drain a 0.7 sq km part of the site. Seepage from springs was measured periodically during the study. The data were used to identify runoff characteristics at the waste burial ground and the reprocessing plant area, 400 meters to the north. Preliminary water budgets for April 1982 through March 1983 were calculated to aid in the development of groundwater flow models to the two areas. Nearly 80% of the measured runoff from the burial ground area was storm runoff; the remaining 20% was base flow. In contrast, only 30% of the runoff leaving the reprocessing plant area was storm runoff, and 70% was base flow. This difference is attributed to soil composition. The burial ground soil consists of clayey silty till that limits infiltration and causes most precipitation to flow to local channels as direct runoff. In contrast, the reprocessing plant area is overlain by alluvial sand and gravel that allows rapid infiltration of precipitation and subsequent steady discharge from the water table to nearby stream channels and seepage faces. Measured total annual runoff and estimated evapotranspiration from the reprocessing plant area exceeded the precipitation by 35%, which suggests that the groundwater basin is larger than the surface water basin. The additional outflow probably includes underflow from bedrock upgradient from the plant, water leakage from plant facilities, and groundwater flow from adjacent basins. (Author 's abstract)

New York↗

A modeling assessment of the thermal regime for an urban sport fishery

Water temperature is almost certainly a limiting factor in the maintenance of a self-sustaining rainbow trout ( Oncorhynchus mykiss , formerly Salmo gairdneri ) and brown trout ( Salmo trutta ) fishery in the lower reaches of the Cache la Poudre River near Fort Collins, Colorado, USA. Irrigation diversions dewater portions of the river, but cold reservoir releases moderate water temperatures during some periods. The US Fish and Wildlife Service’s Stream Network Temperature Model (SNTEMP) was applied to a 31-km segment of the river using readily available stream geometry and hydrological and meteorological data. The calibrated model produced satisfactory water temperature predictions (R 2 =0.88, P <0.001, N=49) for a 62-day summer period. It was used to evaluate a variety of flow and nonflow alternatives to keep water temperatures below 23.3°C for the trout. Supplemental flows or reduced diversions of 3 m 3 /sec would be needed to maintain suitable summer temperatures throughout most of the study area. Such flows would be especially beneficial during weekends when current irrigation patterns reduce flows. The model indicated that increasing the riparian shade would result in little improvement in water temperatures but that decreasing the stream width would result in significant temperature reductions. Introduction of a more thermally tolerant redband trout ( Oncorhynchus sp.), or smallmouth bass ( Micropterus dolomieui ) might prove beneficial to the fishery. Construction of deep pools for thermal refugia might also be helpful.

Environmental Management↗