Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Lake and Reservoir Management”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
USGS2016

Reservoirs and water management influence fish mercury concentrations in the western United States and Canada

Anthropogenic manipulation of aquatic habitats can profoundly alter mercury (Hg) cycling and bioaccumulation. The impoundment of fluvial systems is among the most common habitat manipulations and is known to increase fish Hg concentrations immediately following impoundment. However, it is not well understood how Hg concentrations differ between reservoirs and lakes at large spatial and temporal scales or how reservoir management influences fish Hg concentrations. This study evaluated total Hg (THg) concentrations in 64,386 fish from 883 reservoirs and 1387 lakes, across the western United States and Canada, to assess differences between reservoirs and lakes, as well as the influence of reservoir management on fish THg concentrations. Fish THg concentrations were 1.4-fold higher in reservoirs (0.13 ± 0.011 μg/g wet weight ± standard error) than lakes (0.09 ± 0.006), though this difference varied among ecoregions. Fish THg concentrations were 1.5- to 2.6-fold higher in reservoirs than lakes of the North American Deserts, Northern Forests, and Mediterranean California ecoregions, but did not differ between reservoirs and lakes in four other ecoregions. Fish THg concentrations peaked in three-year-old reservoirs then rapidly declined in 4–12 year old reservoirs. Water management was particularly important in influencing fish THg concentrations, which were up to 11-times higher in reservoirs with minimum water storage occurring in May, June, or July compared to reservoirs with minimum storage occurring in other months. Between-year changes in maximum water storage strongly influenced fish THg concentrations, but within-year fluctuations in water levels did not influence fish THg concentrations. Specifically, fish THg concentrations increased up to 3.2-fold over the range of between-year changes in maximum water storage in all ecoregions except Mediterranean California. These data highlight the role of reservoir creation and management in influencing fish THg concentrations and suggest that water management may provide an effective means of mitigating Hg bioaccumulation in some reservoirs.

Science of the Total Environment↗
USGS2015

Agencies collaborate, develop a cyanobacteria assessment network

Cyanobacteria are a genetically diverse group of photosynthetic microorganisms that occupy a broad range of habitats on land and water all over the world. They release toxins that can cause lung and skin irritation, alter the taste and odor of potable water, and cause human and animal illness. Cyanobacteria blooms occur worldwide, and climate change may increase the frequency, duration, and extent of these bloom events. Rapid detection of potentially harmful blooms is essential to protect humans and animals from exposure. Information about potential for exposure, such as bloom duration, frequency, and extent, is especially critical for developing environmental management decisions during periods of limited resources and funding. The National Research Council (NRC) report Exposure Science in the 21st Century suggested that effectively assessing and mitigating exposures requires techniques for rapid measurement of a stressor, such as an algal bloom, across diverse geographic, temporal, and biologic scales (e.g., various bloom concentrations) and an enhanced infrastructure to address threats [ NRC , 2012]. The report specifically calls for approaches that use diverse information, such as satellite remote sensing, to identify and understand exposures that may pose a threat to ecosystems or human health. A collaborative effort integrates the work of the U.S. Environmental Protection Agency (EPA), NASA, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Geological Survey (USGS) to provide an approach for using satellite ocean color capabilities in U.S. fresh and brackish water quality management decisions. The overarching goal of this collaborative project is to detect and quantify cyanobacteria blooms using satellite data records in order to support the environmental management and public use of U.S. lakes and reservoirs. Satellite remote sensing tools may enable policy makers and environmental managers to assess the sustainability of watershed ecosystems and the services they provide, now and in the future. Satellite technology allows us to develop early-warning indicators of cyanobacteria blooms at the local scale while maintaining continuous national coverage.

Eos, Earth and Space Science News↗
USGS2014

Simulation of the Lower Walker River Basin hydrologic system, west-central Nevada, using PRMS and MODFLOW models

Walker Lake is a terminal lake in west-central Nevada with almost all outflow occurring through evaporation. Diversions from Walker River since the early 1900s have contributed to a substantial reduction in flow entering Walker Lake. As a result, the lake is receding, and salt concentrations have increased to a level in which Oncorhynchus clarkii henshawi (Lahontan Cutthroat trout) are no longer present, and the lake ecosystem is threatened. Consequently, there is a concerted effort to restore the Walker Lake ecosystem and fishery to a level that is more sustainable. However, Walker Lake is interlinked with the lower Walker River and adjacent groundwater system which makes it difficult to understand the full effect of upstream water-management actions on the overall hydrologic system including the lake level, volume, and dissolved-solids concentrations of Walker Lake. To understand the effects of water-management actions on the lower Walker River Basin hydrologic system, a watershed model and groundwater flow model have been developed by the U.S. Geological Survey in cooperation with the Bureau of Reclamation and the National Fish and Wildlife Foundation. The watershed model was developed using the precipitation runoff modeling system (PRMS) and the groundwater flow model was constructed using the MODular groundwater FLOW model (MODFLOW) and both were calibrated for the lower Walker River Basin. These models can be incorporated in an integrated Groundwater and Surface-water FLOW (GSFLOW) model of the lower Walker River Basin. Additionally, the MODFLOW model developed for this study is useful for efficiently simulating long-term and large-scale effects of water-management actions on groundwater hydrology, streamflow, and Walker Lake level, volume, and dissolved-solids concentrations. The lower Walker River Basin PRMS model (LWR_PRMS) was constructed using a subbasin approach to aid in development and calibration, and simulates a 30-year period from 1978 to 2007 using daily time steps. The LWR_PRMS was used to estimate the distribution of groundwater recharge specified in the MODFLOW model. The highest rates of groundwater recharge occur in the Wassuk Range beneath perennial and ephemeral stream channels, whereas lower rates of recharge occur beneath alluvial fans along mountain fronts. The total groundwater recharge estimated using PRMS was about 25,000 acre-feet per year. The lower Walker River Basin MODFLOW (LWR_MF) model simulates an 89-year period using monthly time steps. The LWR_MF was constructed with an initial steady-state simulation to represent dynamic equilibrium conditions from 1908 to 1918 and then a transient simulation representing the period 1919–2007. The model was calibrated using a combination of manual and automated methods of adjusting model parameters to minimize errors between model simulated results and weighted observations of groundwater levels, streamflows, and lake level. Hydrologic conditions simulated with the LWR_MF include the movement and change in storage of groundwater, and the water budgets for Walker River, Walker Lake, and the groundwater system. The LWR_MF computed dissolved-solids concentrations for Walker Lake using simulated lake volume and an assumed constant internal salt mass of 37.2 million tons. Effects of potential changes in water management on future conditions (scenarios) of the lower Walker River Basin hydrologic system and Walker Lake from 2011 to 2070 were evaluated. Several water-management scenarios were considered, including a baseline scenario that represents no changes in system management, improved irrigation efficiencies for the Walker River Indian Irrigation Project (WRIIP), a range of increased streamflows entering the lower Walker River Basin, and, the fallowing of fields on the WRIIP. For the baseline scenario, it was assumed that streamflow conditions from 1981 to 2010 will be repeated in the future. Results indicate that Walker Lake level and volume continue to decline but at a slower rate as the surface area of the lake becomes smaller and lake evaporation decreases. Dissolved-solids concentrations in Walker Lake continue to increase and increase much more rapidly during periods when minimal flows reach the lake due to a diminished lake volume. Alternatively, in years with high runoff, lake level increases are greater and dissolved-solids decreases are greater, compared with equivalent runoffs experienced during 1981–2010. The simulated effects of improving WRIIP efficiencies on Walker River streamflows, Walker Lake inflow, level, and dissolved-solids concentrations, and crop consumptive use, are compared with the baseline reference scenario for a range of irrigation efficiency improvements from 0 to 25 percent over 60 years. Results indicate that water is conserved through a reduction in irrigation-induced groundwater recharge and subsequent groundwater discharge through evapotranspiration. The conserved water mostly goes to increased streamflow to Walker Lake, followed by increased crop consumptive use, then increased evaporation from Weber Reservoir. The simulated effects of increased streamflows at Walker River at Wabuska streamgage (10301500) on Walker Lake inflow, level, and dissolved-solids concentrations, and crop consumptive use, are compared with the baseline scenario after 60 years under two different management methods for Weber Reservoir. Results indicate Walker Lake level and dissolved-solids concentrations stabilized with increased irrigation-season streamflow of about 40,000 acre-feet per year at the Walker River at Wabuska streamgage. Walker Lake level increased, and dissolved-solids concentration decreased, with increased flows of 50,000 acre-feet per year or more. After 60 years with additional irrigation-season streamflows of 50,000 acre-feet per year, Walker Lake level increased by about 48 feet, and lake dissolved-solids concentrations decreased by about 3,000 milligrams per liter (mg/L). With 75,000 acre-feet per year of additional streamflow, Walker Lake level increased by 70 feet, and dissolved-solids concentration decreased by 7,600 milligrams per liter. The effects of fallowing of Walker River Indian Irrigation Project fields from 2007 to 2010 on Walker Lake inflow, level, and dissolved solids were evaluated. Fallowing resulted in a near doubling of Walker River inflow to Walker Lake during this period, an increase in Walker Lake level of about 1.4 feet, and a decrease in dissolved-solids concentration of about 540 mg/L.

Nevada↗
USGS1994

Nutrient additions by waterfowl to lakes and reservoirs: predicting their effects on productivity and water quality

Lakes and reservoirs provide water for human needs and habitat for aquatic birds. Managers of such waters may ask whether nutrients added by waterfowl degrade water quality. For lakes and reservoirs where primary productivity is limited by phosphorus (P), we developed a procedure that integrates annual P loads from waterfowl and other external sources, applies a nutrient load-response model, and determines whether waterfowl that used the lake or reservoir degraded water quality. Annual P loading by waterfowl can be derived from a figure in this report, using the days per year that each kind spent on any lake or reservoir. In our example, over 6500 Canada geese ( Branta canadensis ) and 4200 ducks (mostly mallards, Anas platyrhynchos ) added 4462 kg of carbon (C), 280 kg of nitrogen (N), and 88 kg of P y -1 to Wintergreen Lake in southwestern Michigan, mostly during their migration. These amounts were 69% of all C, 27% of all N, and 70% of all P that entered the lake from external sources. Loads from all external sources totaled 840 mg P m -2 y -1 . Application of a nutrient load-response model to this concentration, the hydraulic load (0.25 m y -1 ), and the water residence time (9.7 y) of Wintergreen Lake yielded an average annual concentration of total P in the lake of 818 mg m -3 that classified the lake as hypertrophic. This trophic classification agreed with independent measures of primary productivity, chlorophyll- a , total P, total N, and Secchi disk transparency made in Wintergreen Lake. Our procedure showed that waterfowl caused low water quality in Wintergreen Lake.

Hydrobiologia↗
USGS2021

Spatial and temporal distribution of radio-tagged Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) suckers in Clear Lake Reservoir and associated spawning tributaries, Northern California, 2015–17

Executive Summary Data from a multi-year radio telemetry study were used to assess seasonal distribution patterns for two long-lived, federally endangered catostomids across substantially different water conditions in Clear Lake Reservoir, northern California. Lost River ( Deltistes luxatus ) and shortnose ( Chasmistes brevirostris ) suckers, two species endemic to the Klamath Basin, were implanted with radio transmitters in each of 3 years in an effort to expand our understanding of seasonal sucker movements within the reservoir and their migrations in spawning tributaries. Clear Lake Reservoir and its tributaries are part of a critical management unit within the Lost River Basin Recovery Unit for populations of Lost River and shortnose suckers. We documented residency and migratory behaviors and how behaviors were affected by lake surface elevations and water management practices. Adult suckers were captured during autumn trammel net sampling in the west lobe of the reservoir and implanted with internal radio transmitters. A total of 163 suckers were radio-tagged (75 in 2014, 64 in 2015, and 24 in 2016); 27 more shortnose suckers were tagged than Lost River suckers to reflect the larger population of shortnose suckers in the reservoir. Sex ratios were approximately equal for each species. Aerial telemetry surveys were used to monitor radio-tagged fish from January 20 to December 2 each year and to document the upstream extent of spawning migrations in the tributaries. Surveys were scheduled more frequently during the spawning season (February–June) when suckers are known to move out of the reservoir and into spawning tributaries.

California↗
USGS2015

Estimating exposure of piscivorous birds and sport fish to mercury in California lakes using prey fish monitoring: a predictive tool for managers

Numerous water bodies in California are listed under the Clean Water Act as being impaired due to mercury (Hg) contamination. The Surface Water Ambient Monitoring Program (SWAMP), via the Bioaccumulation Oversight Group (BOG), has recently completed statewide surveys of contaminants in sport fish tissue from more than 250 lakes and rivers in California and throughout coastal waters. This effort focused on human health issues but did not include beneficial uses by wildlife. Many piscivorous birds such as grebes, terns, cormorants, and mergansers eat fish smaller than those that were sampled by BOG, and sport fish Hg concentrations are not always indicative of wildlife exposure to Hg; therefore, the BOG surveys could not address whether wildlife were at risk due to Hg-induced reproductive impairment in these lakes. We used western grebes ( Aechmophorus occidentalis ) and Clark’s grebes ( Aechmophorus clarkii ) as our index of wildlife exposure to Hg in California lakes. Grebes are widely distributed in lakes throughout California and, as piscivorous waterbirds, are near the top of the food chain in lakes. Additionally, grebes become flightless after they arrive at their summer locations. Thus, grebes are useful representatives for wildlife risk from local, lake-specific contaminant exposure. Grebes also breed at many lakes throughout California, making them susceptible to impaired reproduction due to local Hg contamination. We developed a tool for estimating wildlife and sport fish risk from Hg exposure based on Hg concentrations in prey fish. This quantitative tool can be used to predict Hg concentrations in grebe blood, grebe eggs, and sport fish, thus facilitating a feasible alternative for adequately estimating wildlife exposure when more comprehensive wildlife sampling is not possible. Specifically, we sampled grebes, prey fish, and sport fish simultaneously at 25 lakes throughout California during the spring and summer of 2012 and 2013 when breeding birds are particularly vulnerable to Hg-induced reproductive impairment. We selected lakes based on a combination of factors, including lakes from southern and northern California, of various sizes, shapes, and elevations, with a range of sport fish Hg exposure levels , where largemouth bass ( Micropterus salmoides ) was the primary sport fish, and with a history of use by grebes. Using these factors ensured that our results are representative of a broad range of lakes and reservoirs in California and are comparable to prior BOG studies. Specifically, we addressed three management questions: Does methylmercury pose significant risks to aquatic life in a representative sample of California lakes and reservoirs? Can a correlational approach be applied on a statewide basis to estimate risks to birds? What are appropriate water-quality monitoring requirements to address methylmercury exposure in wildlife?

California↗
USGS2018

Population characteristics of Yellow Perch in a central Appalachia hydropower reservoir

Estimates of population characteristics of sport fishes inform fisheries management decisions and provide feedback on management strategies. Cheat Lake provides an unusual fishery in West Virginia because the hydropower reservoir supports a Yellow Perch Perca flavescens population. We estimated age structure, size structure, condition, total instantaneous mortality, growth, and summer diet for Cheat Lake Yellow Perch based on electrofishing collections in 2012. From 302 individuals, we observed a maximum age of 9 y. Maximum age, average size, and growth of females in the sample exceeded those of males. Cheat Lake Yellow Perch scored low on the relative weight index, but generally exhibited faster growth than other populations, even when compared by sex. Estimated annual survival was 0.63 (95% CI = 0.51–0.78), which is comparable to other exploited populations. These data support the presence of an ontogenetic diet shift from consumption of zooplankton to macroinvertebrates and fishes as Yellow Perch age. This study is the first evaluation we are aware of on Yellow Perch population characteristics in West Virginia, providing baseline data to enhance management decisions and direct future studies.

West Virginia↗
USGS2015

Mercury and methylmercury in reservoirs in Indiana

Mercury (Hg) is an element that occurs naturally, but evidence suggests that human activities have resulted in increased amounts being released to the atmosphere and land surface. When Hg is converted to methylmercury (MeHg) in aquatic ecosystems, MeHg accumulates and increases in the food web so that some fish contain levels which pose a health risk to humans and wildlife that consume these fish. Reservoirs unlike natural lakes, are a part of river systems that are managed for flood control. Data compiled and interpreted for six flood-control reservoirs in Indiana showed a relation between Hg transport, MeHg formation in water, and MeHg in fish that was influenced by physical, chemical, and biological differences among the reservoirs. Existing information precludes a uniform comparison of Hg and MeHg in all reservoirs in the State, but factors and conditions were identified that can indicate where and when Hg and MeHg levels in reservoirs could be highest. As part of a statewide monitoring network for Hg and MeHg in Indiana streams, 66 water samples were collected from four reservoir tailwater sites (downstream near the dams) on a quarterly schedule for 5 years. The reservoirs were Brookville Lake, Cagles Mill Lake, J. Edward Roush Lake, and Mississinewa Lake. Particulate-bound Hg concentrations were significantly lower in tailwater samples than in samples from free-flowing streams in the statewide network. (Free-flowing streams were not affected by dams and were not upstream from these reservoirs.) These data indicated the reduced flow velocity of water upstream from dams was allowing particulate-bound Hg to settle out of the water in the reservoir pools. The concentration ratios of MeHg to Hg were significantly higher in the tailwater samples than in samples from free-flowing streams, and the MeHg to Hg ratios were significantly higher in summer than in other seasons. To evaluate the conditions related to MeHg formation, pools of three reservoirs (Brookville Lake, Monroe Lake, and Patoka Lake) were investigated during summer hydrologic conditions. Water temperature and dissolved oxygen were measured from the water surface to the lake bottom at 10 to 17 transects across each reservoir to identify three thermal strata, defined by water temperature, dissolved oxygen concentration, and depth. Depth-specific water samples were collected from these thermal strata throughout each reservoir, from the headwaters to the dam and from the tailwater. Mercury concentrations higher than 0.04 nanogram per liter (ng/L) were detected in all 53 samples, and MeHg concentrations higher than 0.04 ng/L were detected in 53 percent of the samples. The investigation found a zone of water below 8 or 9 meters, with temperatures less than 18 degrees Celsius and dissolved oxygen less than 3.5 milligrams per liter, extending through nearly half the reservoir area in Monroe Lake and Patoka Lake. This zone had abundant dissolved MeHg and concentration ratios of dissolved MeHg to Hg that ranged from 25 to 82 percent. This zone also had water with pH less than 7 and decreased dissolved sulfate, conditions indicating sulfate reduction by microorganisms that promoted a high potential for the conversion of Hg to MeHg. Reservoir outflow came from this zone at Monroe Lake and contributed to a tailwater concentration ratio for dissolved MeHg to Hg of 56 percent. Reservoir outflow at Patoka Lake was not from this zone, and dissolved MeHg was not detected in the tailwater. In contrast, samples from the summer pool at Brookville Lake had no MeHg detections even though Hg was detected, probably because the water pH higher than 7 inhibited sulfate reduction and did not promote the conversion of Hg to MeHg. Mercury and MeHg concentrations and the concentration ratios of MeHg to Hg in water varied among the six reservoirs in Indiana, and the differences were related to a combination of factors that could apply to other reservoirs. In areas with moderate to high rates of atmospheric Hg wet and dry deposition, Hg runoff and transport to streams and reservoirs was potentially highest for reservoirs with heavily forested watersheds in steep terrains of near-surface bedrock. Methylmercury concentrations and concentration ratios of MeHg to Hg were highest for reservoirs with the longest summer pools and highest inflow-to-outflow retention times, where water-chemistry conditions favoring sulfate reduction promoted conversion of Hg to MeHg. Methylmercury (reported as Hg) in fish-tissue samples collected for the State fish consumption advisory program was used to describe MeHg food-web accumulation and magnification in the reservoirs. The highest percentages of fish-tissue samples with Hg concentrations that exceeded the criterion of 0.30 milligram per kilogram for protection of human health were from Monroe Lake (38 percent) and Patoka Lake (33 percent). A review of the number and size of fish species caught from these two reservoirs resulted in two implications for fish consumption by humans. First, the highest numbers of fish harvested for potential human consumption were species more likely to have MeHg concentrations lower than the human-health criterion (crappie, bluegill, and catfish). Second, although largemouth bass were likely to have MeHg concentrations higher than the human-health criterion, they were caught and released more often than they were harvested. However, the average size largemouth bass (in both reservoirs) and above-average size walleye (in Monroe Lake) that were harvested for potential human consumption were likely to have MeHg concentrations higher than the human-health criterion.

Indiana↗
USGS2016

Climate, invasive species and land use drive population dynamics of a cold-water specialist

Climate change is an additional stressor in a complex suite of threats facing freshwater biodiversity, particularly for cold-water fishes. Research addressing the consequences of climate change on cold-water fish has generally focused on temperature limits defining spatial distributions, largely ignoring how climatic variation influences population dynamics in the context of other existing stressors. We used long-term data from 92 populations of bull trout Salvelinus confluentus – one of North America's most cold-adapted fishes – to quantify additive and interactive effects of climate, invasive species and land use on population dynamics (abundance, variability and growth rate). Populations were generally depressed, more variable and declining where spawning and rearing stream habitat was limited, invasive species and land use were prevalent and stream temperatures were highest. Increasing stream temperature acted additively and independently, whereas land use and invasive species had additive and interactive effects (i.e. the impact of one stressor depended on exposure to the other stressor). Most (58%–78%) of the explained variation in population dynamics was attributed to the presence of invasive species, differences in life history and management actions in foraging habitats in rivers, lakes and reservoirs. Although invasive fishes had strong negative effects on populations in foraging habitats, proactive control programmes appeared to effectively temper their negative impact. Synthesis and applications . Long-term demographic data emphasize that climate warming will exacerbate imperilment of cold-water specialists like bull trout, yet other stressors – especially invasive fishes – are immediate threats that can be addressed by proactive management actions. Therefore, climate-adaptation strategies for freshwater biodiversity should consider existing abiotic and biotic stressors, some of which provide potential and realized opportunity for conservation of freshwater biodiversity in a warming world.

Journal of Applied Ecology↗
USGS2010

Two-dimensional hydrodynamic modeling to quantify effects of peak-flow management on channel morphology and salmon-spawning habitat in the Cedar River, Washington

The Cedar River in Washington State originates on the western slope of the Cascade Range and provides the City of Seattle with most of its drinking water, while also supporting a productive salmon habitat. Water-resource managers require detailed information on how best to manage high-flow releases from Chester Morse Lake, a large reservoir on the Cedar River, during periods of heavy precipitation to minimize flooding, while mitigating negative effects on fish populations. Instream flow-management practices include provisions for adaptive management to promote and maintain healthy aquatic habitat in the river system. The current study is designed to understand the linkages between peak flow characteristics, geomorphic processes, riverine habitat, and biological responses. Specifically, two-dimensional hydrodynamic modeling is used to simulate and quantify the effects of the peak-flow magnitude, duration, and frequency on the channel morphology and salmon-spawning habitat. Two study reaches, representative of the typical geomorphic and ecologic characteristics of the Cedar River, were selected for the modeling. Detailed bathymetric data, collected with a real-time kinematic global positioning system and an acoustic Doppler current profiler, were combined with a LiDAR-derived digital elevation model in the overbank area to develop a computational mesh. The model is used to simulate water velocity, benthic shear stress, flood inundation, and morphologic changes in the gravel-bedded river under the current and alternative flood-release strategies. Simulations of morphologic change and salmon-redd scour by floods of differing magnitude and duration enable water-resource managers to incorporate model simulation results into adaptive management of peak flows in the Cedar River. PDF version of a presentation on hydrodynamic modelling in the Cedar River in Washington state. Presented at the American Geophysical Union Fall Meeting 2010.

Washington↗
USGS2002

Uncertainty in annual streamflow and change in reservoir content data from selected surface-water gaging stations on the lower Colorado River

The lower Colorado River is an important water resource for metropolitan populations, agriculture, and industry in California, Arizona, and Nevada. The Bureau of Reclamation (BOR) manages the river, releasing water stored in Lakes Mead, Mohave, and Havasu, and in other smaller reservoirs as needed so that it can be used by diverters. To help guide river management, streamflow and reservoir content are monitored at strategically located gaging stations along the lower Colorado River, its tributaries, and its diversions. The data obtained from these gaging stations, however, contain uncertainty and are only estimates of the ‘‘true’’ streamflow and reservoir content. As part of a cooperative project with the BOR, the U.S. Geological Survey (USGS) estimated the standard error of the annual discharge for calendar years 1995–99 at 14 streamflow-gaging stations and the standard error of the change in reservoir content at 2 reservoir-content gaging stations (table 1 and fig.1; Anning, 2002). These standard error estimates provide a measure of the random uncertainty for the annual data.

Arizona↗
USGS2017

Gradients in Catostomid assemblages along a reservoir cascade

Serial impoundment of major rivers leads to alterations of natural flow dynamics and disrupts longitudinal connectivity. Catostomid fishes (suckers, family Catostomidae) are typically found in riverine or backwater habitats yet are able to persist in impounded river systems. To the detriment of conservation, there is limited information about distribution of catostomid fishes in impounded rivers. We examined the longitudinal distribution of catostomid fishes over 23 reservoirs of the Tennessee River reservoir cascade, encompassing approximately 1600 km. Our goal was to develop a basin-scale perspective to guide conservation efforts. Catostomid species composition and assemblage structure changed longitudinally along the reservoir cascade. Catostomid species biodiversity was greatest in reservoirs lower in the cascade. Assemblage composition shifted from dominance by spotted sucker Minytrema melanops and buffalos Ictiobus spp. in the lower reservoirs to carpsuckers Carpiodes spp. midway through the cascade and redhorses Moxostoma spp. in the upper reservoirs. Most species did not extend the length of the cascade, and some species were rare, found in low numbers and in few reservoirs. The observed gradients in catostomid assemblages suggest the need for basin-scale conservation measures focusing on three broad areas: (1) conservation and management of the up-lake riverine reaches of the lower reservoirs, (2) maintenance of the access to quality habitat in tributaries to the upper reservoirs and (3) reintroductions into currently unoccupied habitat within species' historic distributions

Tennessee River↗
USGS2018

Assessing the influence of watershed characteristics on chlorophyll a in waterbodies at global and regional scales

Prediction of primary production of lentic water bodies (i.e., lakes and reservoirs) is valuable to researchers and resource managers alike, but is very rarely done at the global scale. With the development of remote sensing technologies, it is now feasible to gather large amounts of data across the world, including understudied and remote regions. To determine which factors were most important in explaining the variation of chlorophyll a (Chl- a ), an indicator of primary production in water bodies, at global and regional scales, we first developed a geospatial database of 227 water bodies and watersheds with corresponding Chl- a , nutrient, hydrogeomorphic, and climate data. Then we used a generalized additive modeling approach and developed model selection criteria to select models that most parsimoniously related Chl- a to predictor variables for all 227 water bodies and for 51 lakes in the Laurentian Great Lakes region in the data set. Our best global model contained two hydrogeomorphic variables (water body surface area and the ratio of watershed to water body surface area) and a climate variable (average temperature in the warmest model selection criteria to select models that most parsimoniously related Chl- a to predictor variables quarter) and explained ~ 30% of variation in Chl- a . Our regional model contained one hydrogeomorphic variable (flow accumulation) and the same climate variable, but explained substantially more variation (58%). Our results indicate that a regional approach to watershed modeling may be more informative to predicting Chl- a , and that nearly a third of global variability in Chl- a may be explained using hydrogeomorphic and climate variables.

Inland Waters↗
USGS2004

The influence of diet, consumption and lipid use on recruitment of white bass

The abundance of white bass ( Morone chrysops ) in Lake Erie has declined in recent years, sparking interest in mechanisms influencing its recruitment. We evaluate two mechanisms affecting recruitment: diet and the potential for competition, and storage of lipid energy reserves and the relationship to overwinter survival. The fish in our study were characteristic of white bass in the northern portion of their range, feeding predominantly on zooplankton. Only the largest age-0 white bass ate fish as a significant portion of their diet. Over the summer sampling period, we found decreasing ration sizes, expressed as a percentage of maximum ration, as the summer progressed with a concomitant decrease in the relative amount of lipid storage. In laboratory experiments, age-0 white bass held at 5°C and given food ad libitum did feed, but at rates that were insufficient to maintain body weight. Loss in weight was accompanied with a loss in lipids at a rate of 2.8 mg of lipids per gram of body weight per day. Based on our data, we concluded that age-0 white bass in Lake Erie were food-limited. Food limitation resulted in reduced growth rates, presumably related to competition with other planktivorous fishes. Reduced growth results in increased mortality and, ultimately, low recruitment through increased risk of predation by larger piscivorous fishes, reduced ability for white bass to switch to more energetically profitable piscivory and the increased likelihood of higher overwinter mortality because of reduced lipid stores.

Michigan, New York, Ohio, Pennsylvania↗
USGS2012

Competing risks and the development of adaptive management plans for water resources: Field reconnaissance investigation of risks to fishes and other aquatic biota exposed to endocrine disrupting chemicals (edcs) in lake mead, Nevada USA

The analysis and characterization of competing risks for water resources rely on a wide spectrum of tools to evaluate hazards and risks associated with their management. For example, waters of the lower Colorado River stored in reservoirs such as Lake Mead present a wide range of competing risks related to water quantity and water quality. These risks are often interdependent and complicated by competing uses of source waters for sustaining biological resources and for supporting a range of agricultural, municipal, recreational, and industrial uses. USGS is currently conducting a series of interdisciplinary case-studies on water quality of Lake Mead and its source waters. In this case-study we examine selected constituents potentially entering the Lake Mead system, particularly endocrine disrupting chemicals (EDCs). Worldwide, a number of environmental EDCs have been identified that affect reproduction, development, and adaptive behaviors in a wide range of organisms. Many EDCs are minimally affected by current treatment technologies and occur in treated sewage effluents. Several EDCs have been detected in Lake Mead, and several substances have been identified that are of concern because of potential impacts to the aquatic biota, including the sport fishery of Lake Mead and endangered razorback suckers (Xyrauchen texanus) that occur in the Colorado River system. For example, altered biomarkers relevant to reproduction and thyroid function in fishes have been observed and may be predictive of impaired metabolism and development. Few studies, however, have addressed whether such EDC-induced responses observed in the field have an ecologically significant effect on the reproductive success of fishes. To identify potential linkages between EDCs and species of management concern, the risk analysis and characterization in this reconnaissance study focused on effects (and attendant uncertainties) that might be expressed by exposed populations. In addition, risk reduction measures that may be of interest to resource managers are considered relative to emerging contaminants in treated effluents, interdependencies among biological resources at risk, and uses of reservoir waters derived from multiple inflows of widely varying qualities. ??2009 ASCE.

Nevada↗
USGS2012

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

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

Arizona, Nevada↗
USGS2015

Bathymetry and capacity of Chambers Lake, Chester County, Pennsylvania

Introduction Chambers Lake is a manmade reservoir on Birch Run, a tributary to West Branch Brandywine Creek in Chester County, Pennsylvania. The lake was created in 1994 after the completion of Multi-Purpose Dam PA-436F (Hibernia Dam), which was built under the Watershed Protection & Flood Control Prevention Act (U.S. Soil Conservation Service, 1991). Hibernia dam is 1,700 feet upstream from the confluence of Birch Run with West Branch Brandywine Creek. The primary objectives for Hibernia Dam were to provide (1) flood control, (2) a supplemental source of water supply for the greater City of Coatesville public water system, and (3) recreational opportunities. The drainage basin of Chambers Lake encompasses approximately 4.5 square miles, and the lake covers a surface area of about 95 acres at normal pool, which is at an elevation of 579.2 feet above the North American Vertical Datum of 1988 (NAVD 88) [580.0 feet above the National Geodetic Vertical Datum of 1929 (NGVD 29)]. The crest of the auxiliary spillway of the dam is 586.6 feet above NAVD 88. The elevation of the auxiliary spillway is important to this investigation because this elevation defines the flood storage capacity of Chambers Lake. Water levels exceeding this elevation are routed through the auxiliary spillway and flow through adjoining woodland to Birch Run. The U.S. Geological Survey (USGS), in cooperation with Chester County Water Resources Authority (CCWRA) and the County of Chester, surveyed the bathymetry and selected above-water features of Chambers Lake in September 2014. The purpose of the survey was to develop an accurate representation of the surface of the bottom of Chambers Lake and to determine the stage area and reservoir-storage capacity relation as of September 2014. CCWRA is responsible for operation of the dam and water-supply reservoir. Since construction, CCWRA has used a stage–storage capacity relation developed from the original survey conducted in the 1990s to estimate the volume of water available for water supply and the available flood storage. The bathymetric mapping effort was initiated due to interest in potential changes in current (2014) storage capacity when compared to the stage–storage capacity relation developed during design. The generated bathymetric surface may serve as a baseline to which temporal changes in storage capacity, owing to sedimentation and other factors, can be compared. In addition, these data will improve the overall accuracy of the stage–storage capacity table that CCWRA uses for reservoir and flood management operations. This report describes the methods used to create a bathymetric map of Chambers Lake for the computation of reservoir storage capacity as of September 2014. The product is a bathymetric map and a table showing the storage capacity of the reservoir at 2-foot increments from minimum usable elevation up to full capacity at the crest of the auxiliary spillway.

Pennsylvania↗
USGS2013

Hydrographic surveys of four narrows within the Namakan reservoir system, Voyageurs National Park, Minnesota, 2011

The U.S. Geological Survey performed multibeam echosounder hydrographic surveys of four narrows in the Namakan reservoir system in August 2011, in cooperation with the International Joint Commission and Environment Canada. The data-collection effort was completed to provide updated and detailed hydrographic data to Environment Canada for inclusion in a Hydrologic Engineering Centers River Analysis System hydraulic model. The Namakan reservoir system is composed of Namakan, Kabetogama, Sand Point, Crane, and Little Vermilion Lakes. Water elevations in the Namakan reservoir system are regulated according to rule curves, or guidelines for water-level management based on the time of year, established by the International Joint Commission. Water levels are monitored by established gages on Crane Lake and the outlet of Namakan Lake at Kettle Falls, but water elevations throughout the system may deviate from these measured values by as much as 0.3 meters, according to lake managers and residents. Deviations from expected water elevations may be caused by between-lake constrictions (narrows). According to the 2000 Rule Curve Assessment Workgroup, hydrologic models of the reservoir system are needed to better understand the system and to evaluate the recent changes made to rule curves in 2000. Hydrographic surveys were performed using a RESON SeaBat™7125 multibeam echosounder system. Surveys were completed at Namakan Narrows, Harrison Narrows, King Williams Narrows, and Little Vermilion Narrows. Hydrographic survey data were processed using Caris HIPS TM and SIPS TM software that interpolated a combined uncertainty and bathymetric estimator (CUBE) surface. Quality of the survey results was evaluated in relation to standards set by the International Hydrographic Organization (IHO) for describing the uncertainty of hydrographic surveys. More than 90 percent of the surveyed areas at the four narrows have resulting bed elevations that meet the IHO “Special Order” quality. Survey datasets published in this report are formatted as text files of x-y-z coordinates and as CARIS Spatial Archive TM (CSAR TM ) files with corresponding metadata.

Minnesota↗