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At least 1,567 records · Page 87Linked to original sources
USGS1997

Water-quality trends for streams and reservoirs in the Research Triangle area of North Carolina, 1983-95

Water-quality and streamflow monitoring data, collected from 1983 to 1995, were analyzed for 34 stream and reservoir sites in a seven-county region within the upper Neuse and upper Cape Fear River Basins. Early data (1983-88) were compiled from U.S. Geological Survey water-quality studies and from the ambient water-quality monitoring network of the North Carolina Department of Environment, Health, and Natural Resources. Analyses of major ions, nutrients, metals, trace elements, and synthetic organic compounds were compiled from samples collected by the U.S. Geological Survey from 1988 to 1995 as part of a continuing project to monitor the water quality of surface-water supplies in the Research Triangle area of North Carolina, and from the North Carolina Department of Environment, Health, and Natural Resources ambient water-quality monitoring network. This report presents the results of analysis of consistently increasing or decreasing trends in concentrations of nitrogen and phosphorus species, suspended sediment, suspended solids, sodium, chloride, iron, manganese, zinc, and chlorophyll a from seasonal Kendall trend analysis on flow-adjusted concentrations for streams and concentrations in lakes. Total phosphorus concentrations also were tested for a step decrease in concentration (step trend) associated with the North Carolina phosphate-detergent ban of 1988. For some other constituents, insufficient data or values below laboratory detection limits precluded trend analysis. A regionwide decrease in total phosphorus, ranging from 25 to 81 percent, was observed that coincided with increased phosphorus removal efforts at municipal wastewater-treatment facilities in the region and the statewide phosphate-detergent ban. Most sites had stable or decreasing trends in nitrogen concentrations; however, increasing trends occurred in the Neuse River near Clayton and at Smithfield, both of which are downstream from the developing Raleigh-Durham area. Chlorophyll a concentrations have increased by 17 to 52 percent per year at monitored reservoirs, except at Cane Creek Reservoir and Lake Michie where there was no trend. No significant trends in suspended-sediment concentrations were observed. Long-term sodium concentrations were available for only a few sites. Of these, decreasing concentrations were observed in the Neuse River at Smithfield and Cane Creek near Orange Grove, and an increasing concentration was observed in University Lake. At most sites, concentrations of manganese, iron, and zinc were stable. Decreasing iron trends were observed in Little River and Cane Creek Reservoirs and Lake Michie. Cane Creek Reservoir also had a decreasing manganese trend. Seven sites, all downstream from wastewater-treatment facilities, were analyzed for zinc trends. A decreasing trend was observed in two of these--Knap of Reeds Creek and Little Lick Creek.

North Carolina↗
USGS2007

Estimation of Sediment Sources Using Selected Chemical Tracers in the Perry Lake and Lake Wabaunsee Basins, Northeast Kansas

In Kansas and nationally, stream and lake sediment is a primary concern as related to several important issues including water quality and reservoir water-storage capacity. The ability to achieve meaningful decreases in sediment loads to reservoirs requires a determination of the relative importance of sediment sources within the contributing basins. To investigate sources of sediment within the Perry Lake and Lake Wabaunsee Basins of northeast Kansas, representative samples of channel-bank sources, surface-soil sources (cropland and grassland), and reservoir bottom sediment were collected, analyzed, and compared. Subbasins sampled within the Perry Lake Basin included Atchison County Lake, Banner Creek Reservoir, Gregg Creek, Mission Lake, and Walnut Creek. The samples were sieved to isolate the less than 63-micron fraction (that is, the silt and clay) and analyzed for selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, and the radionuclide cesium-137 (137Cs). To determine which of the 30 constituents provided the best ability to discriminate between channel-bank and surface-soil sources in the two basins, four selection criteria were used. To be selected, it was required that the candidate constituent (1) was detectable, (2) had concentrations or activities that varied substantially and consistently between the sources, (3) had concentration or activity ranges that did not overlap between the sources, and (4) had concentration or activity differences between the sources that were statistically significant. On the basis of the four selection criteria, total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), and 137Cs were selected. Of the four selected constituents, 137Cs likely is the most reliable indicator of sediment source because it is known to be conservative in the environment. Trace elements were not selected because concentrations in the channel-bank and surface-soil sources generally were similar or did not vary in a consistent manner. To further account for differences in particle-size composition between the sources and the reservoir bottom sediment prior to the sediment-source estimations, constituent ratio and clay-normalization techniques were used. Computed ratios included the ratio of TOC to TN, TOC to TP, and TN to TP. Constituent concentrations (TN, TP, TOC) and activities (137Cs) were normalized by dividing by the percentage of clay. Thus, the sediment-source estimations involved the use of seven sediment-source indicators (that is, three constituent ratios and the clay-normalized concentration or activity for four constituents). Sediment-source estimation for each reservoir was based on a comparison between the reservoir bottom sediment and the end member channel-bank and surface-soil sources. Within the Perry Lake Basin, the seven-indicator consensus indicated that both channel-bank and surface-soil sources were important contributors of the sediment deposited in Atchison County Lake and Banner Creek Reservoir, whereas channel-bank sources were the dominant source of sediment for Mission Lake. On the sole basis of 137Cs activity, surface-soil sources contributed the most sediment to Atchison County Lake, and channel-bank sources contributed the most sediment to Banner Creek Reservoir and Mission Lake. For Perry Lake, both the seven-indicator consensus and 137Cs indicated that channel-bank sources were dominant and that channel-bank sources increased in importance with distance downstream in the Perry Lake Basin. For Lake Wabaunsee, the seven-indicator consensus and 137Cs indicated that both channel-bank and surface-soil sources were important. Given that the relative contribution of sediment from channel-bank and surface-soil sources can vary within and between basins and over time, basin-specific strategies for sediment management and monitoring are appropriate.

Scientific Investigations Report↗
USGS2014

Nearshore bathymetric mapping along a 7-mile reach of Lake Sharpe shoreline near Lower Brule, South Dakota, 2013

Shoreline erosion rates along Lake Sharpe, a Missouri River reservoir, near the community of Lower Brule, South Dakota, were studied previously during 2011–12 by the U.S. Geological Survey, the Lower Brule Sioux Tribe, and Oglala Lakota College. The rapid shoreline retreat has caused many detrimental effects along the shoreline of Lake Sharpe, including losses of cultural sites, recreation access points, wildlife habitat, irrigated cropland, and landmass. The Lower Brule Sioux Tribe is considering options to reduce or stop erosion. One such option for consideration is the placement of discontinuous rock breakwater structures in shallow water to reduce wave action at shore. Information on the depth of water and stability characteristics of bottom material in nearshore areas of Lake Sharpe is needed by the Lower Brule Sioux Tribe to develop structural mitigation alternatives. To help address this need, a bathymetric survey of nearshore areas of Lake Sharpe near Lower Brule, South Dakota, was completed in 2013 by the U.S. Geological Survey in cooperation with the Lower Brule Sioux Tribe. HYPACK® hydrographic survey software was used to plan data collection transects for a 7-mile reach of Lake Sharpe shoreline near Lower Brule, South Dakota. Regular data collection transects and oblique transects were planned to allow for quality-assurance/quality-control comparisons. Two methods of data collection were used in the bathymetric survey: (1) measurement from a boat using bathymetric instrumentation where water was more than 2 feet deep, and (2) wading using Real-Time Kinematic Global Navigation Satellite System equipment on shore and where water was shallower than 2 feet deep. A dual frequency, 24- or 200-kilohertz narrow beam, depth transducer was used in conjunction with a Teledyne Odom CV100 dual frequency echosounder for boat-based data collection. In water too shallow for boat navigation, the elevation and nature of the reservoir bottom were mapped using Real-Time Kinematic Global Navigation Satellite System equipment. Once the data collection effort was completed, data editing was performed in HYPACK® to remove erroneous data points and to apply water-surface elevations. Maps were developed separately for water depth and bottom elevation for the study area. Lines of equal water depth for 2, 3, 3.5, 4, and 5 feet from the water surface to the lake bottom were mapped in nearshore areas of Lake Sharpe. Overall, water depths stay shallow for quite a distance from shore. In the 288 transects that crossed a 2 foot depth line, this depth occurred an average of 88 feet from shore. Similarly, in the 317 transects that crossed a 3 foot depth line, this did not occur until an average of 343 feet from shore. Elevation contours of the lake bottom were mapped primarily for elevations ranging from 1,419 to 1,416 feet above North American Vertical Datum of 1988. Horizontal errors of the Real-Time Kinematic Global Navigation Satellite System equipment for the study area are essentially inconsequential because water depth and bottom elevation were determined to change relatively slowly. The estimated vertical error associated with the Real-Time Kinematic Global Navigation Satellite System equipment for the study area ranges from 0.6 to 0.9 inch. This vertical error is small relative to the accuracy of the bathymetric data. Accuracy assessments of the data collected for this study were computed according to the National Standard for Spatial Data Accuracy. The maps showing the lines of equal water depth and elevation contours of the lake bottom are able to support a 1-foot contour interval at National Standards for Spatial Data Accuracy vertical accuracy standards, which require a vertical root mean squared error of 0.30 foot or better and a fundamental vertical accuracy calculated at the 95-percent confidence level of 0.60 foot or better.

South Dakota↗
USGS2010

Large reservoirs: Chapter 17

Large impoundments, defined as those with surface area of 200 ha or greater, are relatively new aquatic ecosystems in the global landscape. They represent important economic and environmental resources that provide benefits such as flood control, hydropower generation, navigation, water supply, commercial and recreational fisheries, and various other recreational and esthetic values. Construction of large impoundments was initially driven by economic needs, and ecological consequences received little consideration. However, in recent decades environmental issues have come to the forefront. In the closing decades of the 20th century societal values began to shift, especially in the developed world. Society is no longer willing to accept environmental damage as an inevitable consequence of human development, and it is now recognized that continued environmental degradation is unsustainable. Consequently, construction of large reservoirs has virtually stopped in North America. Nevertheless, in other parts of the world construction of large reservoirs continues. The emergence of systematic reservoir management in the early 20th century was guided by concepts developed for natural lakes (Miranda 1996). However, we now recognize that reservoirs are different and that reservoirs are not independent aquatic systems inasmuch as they are connected to upstream rivers and streams, the downstream river, other reservoirs in the basin, and the watershed. Reservoir systems exhibit longitudinal patterns both within and among reservoirs. Reservoirs are typically arranged sequentially as elements of an interacting network, filter water collected throughout their watersheds, and form a mosaic of predictable patterns. Traditional approaches to fisheries management such as stocking, regulating harvest, and in-lake habitat management do not always produce desired effects in reservoirs. As a result, managers may expend resources with little benefit to either fish or fishing. Some locally expressed effects, such as turbidity and water quality, zooplankton density and size composition, or fish growth rates and assemblage composition, are the upshot of large-scale factors operating outside reservoirs and not under the direct control of reservoir managers. Realistically, abiotic and biotic conditions in reservoirs are shaped by factors working inside and outside reservoirs, with the relative importance of external factors differing among reservoirs. With this perspective, large reservoirs are viewed from a habitat standpoint within the framework of a conceptual model in which individual reservoir characteristics are influenced by both local- and landscape-scale factors (Figure 17.1). In the sections that follow, how each element of this hierarchical model influences habitat and fish assemblages in reservoirs is considered. Important in-reservoir habitat issues and reservoirs as part of larger systems, where reservoir management requires looking for real solutions outside individual reservoirs are described.

Book chapter↗
USGS2019

Linking sedimentation and erosion patterns with reservoir morphology and dam operations during streambed drawdowns in a flood-control reservoir in the Oregon Cascades

Since water-year (WY) 2011, pool levels at Fall Creek Lake, Oregon, are temporarily lowered to an elevation near historical streambed each fall, creating free-flowing channel conditions that facilitate downstream passage of juvenile spring Chinook salmon. These drawdown operations have also mobilized substantial quantities of predominantly fine (<2 mm) reservoir sediment as well as some coarser gravels. To assess the potential impact of reservoir sediment erosion and transport on downstream reach morphology and habitats, linkages between reservoir sedimentation in Fall Creek Lake and drawdown-related reservoir erosion are inferred from geomorphic mapping and volumetric change analyses developed from high resolution aerial photographs and digital elevation models of the empty reservoir. Recent and historical drawdown operations have helped maintain a thalweg in much of Fall Creek Lake, constraining most coarse-grained sediment transport and re-deposition, whereas fine-grained deposition has mainly occurred on the former floodplain and lowermost reservoir reaches. Fine-grained sediment deposits are thickest and bury pre-dam morphology immediately upstream of the dam where they are accessible to fluvial erosion during streambed drawdown operations. Farther from the dam, where pre-dam morphology has not been buried, erosion is limited to sediment accumulation in the reservoir thalweg and minor tributary and ‘drawdown’ channels. In former floodplain regions of the reservoir not adjacent to the thalweg, thicker sediment deposits are inaccessible to fluvial erosion at full streambed drawdown. Altogether, these findings highlight controls on patterns and processes of reservoir erosion during drawdowns. This understanding of long-term sedimentation and streambed-drawdown erosion at Fall Creek Lake allows better evaluation and anticipation of the timing, magnitude, and sediment characteristics delivered to downstream reaches.

Oregon↗
USGS1996

Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the Vermejo Project area and the Maxwell National Wildlife Refuge, Colfax County, northeastern New Mexico, 1993

Based on findings of limited studies during 1989-92, a reconnaissance investigation was conducted in 1993 to assess the effects of the Vermejo Irrigation Project on water quality in the area of the project, including the Maxwell National Wildlife Refuge. This project was part of a U.S. Department of the Interior National Irrigation Water-Quality Program to determine whether irrigation drainage has caused or has the potential to cause significant harmful effects on human health, fish, and wildlife and whether irrigation drainage may adversely affect the suitability of water for other beneficial uses. For this study, samples of water, sediment, and biota were collected from 16 sites in and around the Vermejo Irrigation Project prior to, during the latter part of, and after the 1993 irrigation season (April, August-September, and November, respectively). No inorganic constituents exceeded U.S. Environmental Protection Agency drinking-water standards. The State of New Mexico standard of 750 micrograms per liter for boron in irrigation water was exceeded at three sites (five samples), though none exceeded the livestock water standard of 5,000 micrograms per liter. Selenium concentrations exceeded the State of New Mexico chronic standard of 2 micrograms per liter for wildlife and fisheries water in at least eight samples from five sites. Bottom-sediment samples were collected and analyzed for trace elements and compared to concentrations of trace elements in soils of the Western United States. Concentrations of three trace elements at eight sites exceeded the upper values of the expected 95-percent ranges for Western U.S. soils. These included molybdenum at one site, selenium at seven sites, and uranium at four sites. Cadmium and copper concentrations exceeded the National Contaminant Biomonitoring Program 85th percentile in fish from six sites. Average concentrations of selenium in adult brine flies (33.7 μ g/g dry weight) were elevated above concentrations in other invertebrates. Concentrations of other elements were below their respective toxicity levels. Plants, invertebrates, fish, and fish fillets were collected and analyzed. These analyses were compared to diagnostic criteria and to each other to determine the extent of bioaccumulation of trace elements. Plants contained larger dry weight concentrations of aluminum, arsenic, boron, chromium, iron, lead, magnesium, manganese, nickel, and vanadium than invertebrates and fish. Adult brine flies, gathered from playas, contained larger geometric mean dry weight concentrations of boron, magnesium, and selenium than other invertebrates. Of all samples collected, the largest mercury concentrations were found in fish fillets, although these concentrations were below levels of concern. Mercury and selenium bioaccumulation was evident in various habitats of the study area. Biological samples from Natural playa, an endemic wetland, and Half playa, a playa that receives additional water through seepage and irrigation delivery canals, generally had elevated concentrations of boron, iron, magnesium, and selenium than samples from reservoir and river sites. Selenium concentrations were lowest in biota from the two reservoir sites, although a wetland immediately downstream from the dam impounding Lake No. 13 (created by seepage from the reservoir) had elevated concentrations of selenium in biota. The geometric mean selenium concentration of whole-fish samples, except those from Lakes No. 13 and No. 14, exceeded the 5- μ g/g dry weight selenium concentration that demarcates the approximate lower limit of the threshold range of concentrations that have freen associated with adverse effects on piscine reproduction. Biota collected on and in the area around Maxwell National Wildlife Refuge contained concentrations of selenium that are in the lower range of threshold values that have been associated (dietarily) with risks of avian reproductive abnormalities. Bottom-sediment samples from two sites downstream from the irrigation project were collected and analyzed for 23 organic compounds (principally organochlorine pesticide residues). Three compounds were detected at the two sites: DDD was found at 0.2 microgram per kilogram, DDE was detected at 0.1 microgram per kilogram at both sites, and chlordane was detected at 1 microgram per kilogram. None of the 28 whole-fish and fillet samples analyzed for PCB and organochlorine pesticide residues contained any of the 23 organic compounds tested for at concentrations higher than the analytical reporting limit (less than 0.01 μ g/g wet weight). Concentrations of inorganic analytes were generally within established guidelines or expected concentrations for water, sediment, and biota. lirigation-return flows were found to be unrelated to adverse effects in biota.

New Mexico↗
USGS2010

Water volume and sediment accumulation in Lake Linganore, Frederick County, Maryland, 2009

To assist in understanding sediment and phosphorus loadings and the management of water resources, a bathymetric survey was conducted at Lake Linganore in Frederick County, Maryland in June 2009 by the U.S. Geological Survey, in cooperation with the City of Frederick and Frederick County, Maryland. Position data and water-depth data were collected using a survey grade echo sounder and a differentially corrected global positioning system. Data were compiled and edited using geographic information system software. A three-dimensional triangulated irregular network model of the lake bottom was created to calculate the volume of stored water in the reservoir. Large-scale topographic maps of the valley prior to inundation in 1972 were provided by the City of Frederick and digitized. The two surfaces were compared and a sediment volume was calculated. Cartographic representations of both water depth and sediment accumulation were produced along with an area/capacity table. An accuracy assessment was completed on the resulting bathymetric model. Vertical accuracy at the 95-percent confidence level for the collected data, the bathymetric surface model, and the bathymetric contour map was calculated to be 0.95 feet, 1.53 feet, and 3.63 feet, respectively. The water storage volume of Lake Linganore was calculated to be 1,860 acre-feet at full pool elevation. Water volume in the reservoir has decreased by 350 acre-feet (about 16 percent) in the 37 years since the dam was constructed. The total calculated volume of sediment deposited in the lake since 1972 is 313 acre-feet. This represents an average rate of sediment accumulation of 8.5 acre-feet per year since Linganore Creek was impounded. A sectional analysis of sediment distribution indicates that the most upstream third of Lake Linganore contains the largest volume of sediment whereas the section closest to the dam contains the largest amount of water. In comparison to other Maryland Piedmont reservoirs, Lake Linganore was found to have one of the lowest sedimentation rates at 0.26 cubic yards per year per acre of drainage area. Sedimentation rates in other comparable Maryland reservoirs were Prettyboy Reservoir (filling at a rate of 2.26 cubic yards per year per acre), Loch Raven Reservoir (filling at a rate of 0.88 cubic yards per year per acre) and Piney Run Reservoir (filling at a negligible rate).

Scientific Investigations Report↗
USGS1976

Lakes Marion-Moultrie stream system investigation, South Carolina : Part II-Simulation Studies

A stream-reservoir model was developed to simulate the operation of the Lakes Marion-Moultrie, South Carolina, reservoir system. The reservoir system is operated under the assumption of a 3-day prior knowledge of inflows. This information is attainable from the ooperational reservoir-inflow forecasting model developed in the Part I report. The model, developed for this part of the study, incorporates an inflow component, a diversion-canal component, and a reservoir system component and is capable of evaluating the performance of the reservoir systemem for a variety of operating rule conditions. All model components were verified using observed reservoir input and output data for a 6-year (1967-72 water years) period. In addition, a long-term 31-year simulation under present rule of operation was performed and the results summarized statistically. The model may be used for simulating other rule curves of operation for planning studies of reservoir system performance. (See also W75-05646) (Woodard-USGS)

South Carolina↗
USGS1991

Hydrologic and geochemical approaches for determining ground-water flow components

Lyman Lake is an irrigation-storage reservoir on the Little Colorado River near St. Johns, Arizona. The main sources of water for the lake are streamflow in the Little Colorado River and ground-water inflow from the underlying Coconino aquifer. Two approaches, a hydrologic analysis and a geochemical analysis, were used to compute the quantity of ground-water flow to and from Lyman Lake. Hydrologic data used to calculate a water budget were precipitation on the lake, evaporation from the lake, transpiration from dense vegetation, seepage through the dam, streamflow in and out of the lake, and changes in lake storage. Geochemical data used to calculate the ground-water flow components were major ions, trace elements, and the stable isotopes of hydrogen and oxygen. During the study, the potentiometric level of the Coconino aquifer was above the lake level at the upstream end of the lake and below the lake level at the downstream end. Hydrologic and geochemical data indicate that about 10 percent and 8 percent, respectively, of the water in the lake is ground-water inflow and that about 35 percent of the water in the Little Colorado River 6 miles downgradient from the lake near Salado Springs is ground water. These independent estimates of ground-water flow derived from each approach are in agreement and support a conceptual model of the water budget.

Conference Paper↗
USGS2006

Investigations of the Effects of Synthetic Chemicals on the Endocrine System of Common Carp in Lake Mead, Nevada and Arizona

Introduction: Lake Mead is the largest reservoir by volume in the United States and was created by the construction of the 221-meter high Hoover Dam in 1935 at Black Canyon on the lower Colorado River between Nevada and Arizona (fig. 1). Inflows of water into the lake include three rivers, Colorado, Virgin, and Muddy; as well as Las Vegas Wash, which is now perennial because of discharges from municipal wastewater treatment plants (Covay and Leiker, 1998) and urban stormwater runoff. As the population within the Las Vegas Valley began to increase in the 1940s, the treated effluent volume also has increased and in 1993 it constituted about 96 percent of the annual discharge of Las Vegas Wash (Bevans and others, 1996). The mean flow of Las Vegas Wash into Las Vegas Bay from 1992 to 1998 was about 490,000 m3/d (Preissler and others, 1999) and in 2001 increased to 606,000 m3/d (U.S. Bureau of Reclamation, 2001). The nutrient concentration in most areas of the lake is low, but wastewater discharged into Las Vegas Bay has caused an increased level of nutrients and primary productivity (aquatic plant and algal production) in this area of the lake (LaBounty and Horn, 1997). A byproduct of this increase in productivity has been the establishment of an important recreational fishery in Las Vegas Bay. However, concentrations of chlorophyll a (a measure of algal biomass) have also increased (LaBounty and Horn, 1997). In the spring of 2001, parts of Lake Mead experienced massive algal blooms. In addition to nutrient loading by wastewater, the presence of numerous synthetic chemicals in water, bottom sediments, and in fish tissue also has been reported (Bevans and others, 1996). Synthetic chemicals discharging into Las Vegas Bay and Lake Mead (fig. 1) originate from several sources that include surplus residential-irrigation water runoff, stormwater runoff, subsurface inflow, and tertiary treated sewage effluent discharging from three sewage-treatment plants. Chemicals detected in Las Vegas Wash and Bay environments include polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (including DDT and DDE), and 'emerging contaminants' such as fragrances/musks, flame retardants, triclosan and its breakdown products, personal care products, and pharmaceuticals (Bevans and others, 1996; Boyd and Furlong, 2002; Leiker and others, in press). Many of these compounds are able to interact with the endocrine system of animals and potentially cause reproductive impacts. The National Park Service (NPS) manages Lake Mead National Recreation Area (LMNRA) with about 8 million yearly visitors including 500,000 anglers drawn to its world-class recreational fishery. The U.S. Fish and Wildlife Service (FWS) provides management for the federally designated, endangered razorback sucker (Xyrauchen texanus) and for more than 180 species of migratory birds that utilize LMNRA surface waters. These multiple uses of surface water in the area demonstrate their vital importance to the LMNRA as well as the need to maintain the quality of water at levels that are adequate for these uses.

Fact Sheet↗
USGS1999

Water budget and water quality of Ward Lake, flow and water-quality characteristics of the Braden River estuary, and the effects of Ward Lake on the hydrologic system, west-central Florida

The Braden River is the largest tributary to the Manatee River. The river was dammed in 1936 to provide the city of Bradenton a source of freshwater supply. The resulting impoundment was called Ward Lake and had a storage capacity of about 585 million gallons. Reconstruction in 1985 increased the size of the reservoir to about 1,400 million gallons. The lake has been renamed the Bill Evers Reservoir and drains about 59 square miles. The Braden River watershed can be subdivided into three hydrologic reaches. The upper reach consists of a naturally incised free-flowing channel. The middle reach consists of a meandering channel affected by backwater as a result of the dam. The lower reach is a tidal estuary. Water budgets were calculated for the 1993 through 1997 water years. Mean surface-water inflow to Ward Lake for the 5-year period was 1,645 inches per year (equivalent depth over the surface of the lake), or about 81.8 percent of total inflow. Mean ground-water inflow was 311 inches per year, or about 15.5 percent. A mean of 55 inches of rain fell directly on the lake and accounted for only 2.7 percent. Mean surface-water outflow was 1,736 inches, or about 86.4 percent of total water leaving the lake. There was no net ground-water outflow from the lake. Mean surface-water withdrawal for public supply was 229 inches per year, or about 11.4 percent. Mean evaporation was 45 inches and accounted for only 2.2 percent of the mean outflow. Change in lake storage on the budget was negligible. Most chemical constituents contained in water flowing to Ward Lake meet the standards specified by the Florida Department of Environmental Protection and the U.S. Environmental Protection Agency. Phosphorus is the exception, exceeding the U.S. Environmental Protection Agency limits of 0.10 milligram per liter in most samples. However, the source of the phosphorus is naturally occurring phosphate deposits underlying the watershed. Organic nitrogen and orthophosphate are the dominant species of nutrients in the streams and the lake. A major source of water to the streams is the surficial aquifer system. Mineralized water pumped from the intermediate aquifer system and the Upper Floridan aquifer for irrigation of agricultural areas or golf courses has influenced the chemical composition of the surficial aquifer and surface-water systems. The Braden River estuary receives freshwater inflow from Ward Lake and from three major streams discharging downstream from the dam. Salinity levels in the estuary are affected by freshwater flow from these sources and by antecedent conditions in the estuary prior to flow events. The lowest salinity levels are often measured at the confluence with Williams and Gap Creeks rather than at the outfall from the lake. The chemical composition of water flowing from the tributaries to the estuary is similar to the chemical composition of water in the tributaries flowing to Ward Lake and does not appear to be affected by brackish water from high tides. Nitrogen concentrations in water from Glen Creek were greater than in water from all other tributaries in the watershed. Fertilizer from orange groves and stormwater runoff from urban and industrial areas affect the water quality in Glen Creek. The effects of the reservoir on the hydrology of the watershed were to change the middle reach of the river from a brackish water estuary ecosystem to a freshwater lake ecosystem, raise water levels in the surficial aquifer system adjacent to the river, change water quality, and reduce freshwater flow to the estuary during periods of low flow. The lake acts as a sink for total organic carbon, dissolved solids, calcium, chloride, and sulfate, thereby decreasing loads of these constituents to the estuary.

Florida↗
USGS1985

Ground water in Utah - A summary description of the resource and its related physical environment

Ground water is one of Utah’s most extensive and valuable natural resources. Because of its widespread occurrence in both wet and dry areas, ground water has been, and is a major factor affecting economic growth and development of the State. In some areas, ground water is used to supplement streamflow for irrigation, public supply, and other uses. In other areas, it is the only water available for use. Many communities obtain their entire water supply from ground-water sources (wells and springs) as do numerous rural and suburban households throughout the State. The ground-water reservoirs of Utah contain tremendous quantities of water – many times more than the quantity stored in all the lakes (including Great Salt Lake) and the surface-water reservoirs of the State combined. Water that discharges from those underground reservoirs in seeps and springs is vital in sustaining the flow of streams during dry summer months and in providing the water needed to maintain important wetland habitats. Those same underground reservoirs also provide large quantities of water in carryover storage for use during prolonged droughts. The U.S. Geological survey, under cooperative programs with the Utah department of Natural resources and other Federal, State, and local agencies has been studying Utah’s ground-water resources since 1897. Much information has been gained during those studies about the occurrence, availability, and quality of ground water; the withdrawal and use of the water; and the effects of withdrawal. This report summarizes that information in nontechnical language, which is designed for all readers. Readers interested in more detailed information about ground water in specific areas of Utah are referred to the reports listed by LaPray and Hamblin (1980).

Utah↗
USGS2015

Estimating spawning times of Alligator Gar ( Atractosteus spatula ) in Lake Texoma, Oklahoma

In 2013, juvenile Alligator Gar were sampled in the reservoir-river interface of the Red River arm of Lake Texoma. The Red River, which flows 860 km along Oklahoma’s border with Texas, is the primary in-flow source of Lake Texoma, and is impounded by Denison Dam. Minifyke nets were deployed using an adaptive random cluster sampling design, which has been used to effectively sample rare species. Lapilli otoliths (one of the three pair of ear stones found within the inner ear of fish) were removed from juvenile Alligator Gar collected in July of 2013. Daily ages were estimated by counting the number of rings present, and spawn dates were back-calculated from date of capture and subtracting 8 days (3 days from spawn to hatch and 5 days from hatch to swimup when the first ring forms). Alligator Gar daily age estimation ranged from 50 to 63 days old since swim-up. Spawn dates corresponded to rising pool elevations of Lake Texoma and water pulses of tributaries.

Proceedings of the Oklahoma Academy of Science↗
USGS2011

Relations between hydrology, water quality, and taste-and-odor causing organisms and compounds in Lake Houston, Texas, April 2006-September 2008

Lake Houston is a surface-water-supply reservoir and an important recreational resource for the city of Houston, Texas. Growing concerns over water quality in Lake Houston prompted a detailed assessment of water quality in the reservoir. The assessment focused on water-quality constituents that affect the aesthetic quality of drinking water. The hydrologic and water-quality conditions influencing the occurrence of taste-and-odor causing organisms and compounds in Lake Houston were assessed using discrete and continuously monitored water-quality data collected during April 2006– September 2008. The hydrology of Lake Houston is characterized by rapidly changing conditions. During inflow events, water residence time can change by orders of magnitude within a matter of hours. Likewise, the reservoir can stratify and destratify over a period of several hours, even during non-summer and at relatively short water residence times, given extended periods with warm temperatures and little wind. The rapidly changing hydrology likely influences all other aspects of water quality in Lake Houston, including the occurrence of taste-and-odor causing organisms and compounds. Water quality in Lake Houston varied with respect to season and water residence time but typically was indicative of turbid, eutrophic to hypereutrophic conditions. In general, turbidity and nutrient concentrations were largest during non-summer (October–May) and when water residence times were relatively short (less than 100 days), which reflects the influence of inflow events on water-quality conditions. Large inflow events can cause substantial changes in water-quality conditions over relatively short periods of time (hours). The taste-and-odor causing organisms cyanobacteria and actinomycetes bacteria were always present in Lake Houston. Cyanobacterial biovolume was largest during summer (June– September) and when water residence time was greater than 100 days. Annual maxima in cyanobacterial biovolume occurred during July-September of each year, when temperatures were larger than 27 degrees Celsius and water residence times were longer than 400 days. In contrast, actinomycetes bacteria were most abundant during non-summer and when water residence times were less than 100 days, reflecting the close association between these organisms and transport of suspended sediments. Geosmin and 2-methylisoborneol are the taste-and-odor causing compounds most commonly produced by cyanobacteria and actinomycetes bacteria. Geosmin was detected more frequently (62 percent of samples) than 2-methylisoborneol (29 percent of samples) in Lake Houston. Geosmin exceeded the human detection threshold (10 nanograms per liter) only once during the study period and 2-methylisoborneol exceeded the human detection threshold twice. Manganese is a naturally occurring trace element that can occasionally cause taste-andodor problems in drinking water. Manganese concentrations exceeded the human detection threshold (about 50 micrograms per liter) in about 50 percent of samples collected near the surface and 84 percent of samples collected near the bottom. The cyanotoxin microcystin was detected relatively infrequently (16 percent of samples) and at small concentrations (less than or equal to 0.2 micrograms per liter). The abundance of the taste-and-odor causing organisms cyanobacteria and actinomycetes bacteria in Lake Houston was coupled with inflow events and subsequent changes in water-quality conditions. Cyanobacterial biovolume (biomass) in Lake Houston was largest during warm periods with little inflow and relatively small turbidity values. In contrast, actinomycetes bacteria were most abundant following inflow events when turbidity was relatively large. Severe taste-and-odor problems were not observed during the study period, precluding quantification of the hydrologic and water-quality conditions associated with large concentrations of taste-and-odor causing compounds and development of predictive models. Reservoir inflow (water residence time) and turbidity, variables related to the abundance of potential taste-andodor causing organisms, are currently (2011) continuously measured in Lake Houston, and predictive models could be developed in the future when the hydrologic and water-quality conditions associated with taste-and-odor problems have been better quantified. Seasonal and water residence time influences on water-quality conditions altered relations between hydrologic and water-quality conditions and taste-and-odor causing organisms and compounds. Future data collection and development of predictive models need to account for the variability associated with season and water residence time.

Texas↗
USGS2022

Nonlinear multidecadal trends in organic matter dynamics in Midwest reservoirs are a function of variable hydroclimate

Dissolved organic matter (DOM) and particulate organic matter (POM) can influence biogeochemical processes in aquatic systems. An understanding, however, of the source, composition, and processes driving inland reservoir organic matter (OM) cycling at a regional scale over the long term is currently unexplored. Here, we quantify decadal patterns (> 20 yr) of DOM quantity and composition and POM in 40 reservoirs in the midcontinent United States. We built 184 Random Forest models to identify how the relative influence of watershed characteristics and limnological parameters on OM dynamics may vary over time and in synchrony with hydroclimatic anomalies. The reservoir OM quantity and composition varied nonmonotonically through time and in contrast to lake browning observed in the northern hemisphere. Reservoir DOM composition switched from humic and aromatic during wet summers to aliphatic, potentially autochthonous DOM during particularly prolonged dry summers in the mid-2000s. The shift in reservoir DOM quantity and composition could be attributed to the change in time-varying control of watershed and limnological factors mediated by the hydroclimatic conditions. Watershed control (e.g., percent crops) was predominant during wet summers, while the effect of reservoir morphology (e.g., maximum depth) and water quality parameters (e.g., Secchi depth, chlorophyll a ) were evident during dry summers. Thus, future predictions of drier conditions may promote “greening” with negative implications for reservoir water quality and treated drinking water. Considering the nonlinear nature of reservoir OM dynamics and its controls will help to better mitigate water quality issues in these constructed systems increasingly impacted by global changes.

Missouri↗
USGS2023

Bathymetric contour maps, surface area and capacity tables, and bathymetric change maps for selected water-supply lakes in north-central and west-central Missouri, 2020

Bathymetric data were collected at 10 water-supply lakes in north-central and west-central Missouri by the U.S. Geological Survey (USGS) in cooperation with the Missouri Department of Natural Resources and in collaboration with various local agencies, as part of a multiyear effort to establish or update the surface area and capacity tables for the surveyed lakes. The lakes were surveyed in June and July 2020. Seven of the lakes had been surveyed by the USGS between 2002 and 2007, and the recent surveys were compared to the earlier surveys to document changes in the bathymetric surface and capacity of the lake and produce a bathymetric change map. Bathymetric data were collected using a high-resolution multibeam mapping system mounted on a boat. Supplemental depth data at two of the lakes were collected in shallow areas with an acoustic Doppler current profiler on a remote-controlled boat. Data points from the various sources were exported at a gridded data resolution appropriate to each lake, either 0.82 foot or 1.64 feet. Data outside the multibeam survey extent and greater than the surveyed water-surface elevation generally were obtained from data collected using aerial light detection and ranging (lidar) point cloud data, except at Holden City Lake. A linear enforcement technique was used to add points to the dataset in areas of sparse data (the upper ends of coves where the water was shallow or aquatic vegetation precluded data acquisition) based on surrounding multibeam and upland data values. The various point datasets were used to produce a three-dimensional triangulated irregular network surface of lake-bottom elevations for each lake. A surface area and capacity table was produced from the three-dimensional surface for each lake showing surface area and capacity at specified lake water-surface elevations. Various quality-assurance tests were conducted to ensure quality data were collected with the multibeam, including beam angle checks and patch tests. Additional quality-assurance tests were conducted on the gridded bathymetric data from the survey, the bathymetric surface created from the gridded data, and the contours created from the bathymetric survey. If data from a previous bathymetric survey existed at a given lake, a bathymetric change map was generated from the elevation difference between the previous survey and the 2020 bathymetric survey data points. After reconciling any vertical datum disagreement between the previous survey and the 2020 survey, coincident points between the surveys were identified, and a bathymetric change map was generated using the coincident point data. A decrease in capacity was observed at nearly all the lakes for which a previous survey existed, and the mean bathymetric change between the surveys was positive at all the lakes. The decrease in capacity at the primary spillway elevation ranged from –0.4 percent at Edwin A Pape Lake to 9.4 percent at upper Higginsville Reservoir. The mean bathymetric change ranged from 0.03 foot at Garden City New Lake to 1.75 feet at Harrisonville City Lake, which corresponds to a time-averaged mean bathymetric change ranging from 0.002 foot per year at Garden City New Lake to 0.132 foot per year at Harrisonville City Lake. The computed volumetric sedimentation rate generally ranged from 0.04 to 4.91 acre-feet per year at Garden City New Lake and Holden City Lake, respectively; however, Harrisonville City Lake had a substantially larger volumetric sedimentation rate of 42.7 acre-feet per year, corresponding to the substantial mean bathymetric change of 1.75 feet and combined with the relatively shorter interval between surveys. Harrisonville City Lake also had the second-largest decrease in capacity at the spillway elevation of 5.9 percent. As with the 2019 surveys, some changes observed in the bathymetric change maps likely result from the difference in data collection equipment and techniques between the surveys. Certain apparent erosional features around the perimeter of certain lakes may be the result of wave action or compaction of sediments exposed to air during low-water years, or may indicate an unidentified but systemic error in the older singlebeam echosounder survey data.

Missouri↗
USGS2020

Microplastics in Lake Mead National Recreation Area, USA: Occurrence and biological uptake

Microplastics are an environmental contaminant of growing concern, but there is a lack of information about microplastic distribution, persistence, availability, and biological uptake in freshwater systems. This is especially true for large river systems like the Colorado River that spans multiple states through mostly rural and agricultural land use. This study characterized the quantity and morphology of microplastics in different environmental compartments in two large reservoirs along the Colorado River: Lakes Mead and Mohave, within Lake Mead National Recreation Area. To assess microplastic occurrence, surface water and surficial sediment were sampled at a total of nine locations. Sampling locations targeted different sub-basins with varying levels of anthropogenic impact. Las Vegas Wash, a tributary which delivers treated wastewater to Lake Mead, was also sampled. A sediment core (33 cm long, representing approximately 19 years) was extracted from Las Vegas Bay to assess changes in microplastic deposition over time. Striped bass (Morone saxatilis), common carp (Cyprinus carpio), quagga mussels (Dreissena bugensis), and Asian clams (Corbicula fluminea) were sampled at a subset of locations to assess biological uptake of microplastics. Microplastic concentrations were 0.44-9.7 particles/cubic meter at the water surface and 87.5-1,010 particles/kilogram dry weight (kg dw) at the sediment surface. Sediment core concentrations were 220-2,040 particles/kg dw, with no clear increasing or decreasing trend over time. Shellfish microplastic concentrations ranged from 2.7-105 particles/organism, and fish concentrations ranged from 0-19 particles/organism. Fibers were the most abundant particle type found in all sample types. Although sample numbers are small, microplastic concentrations appear to be higher in areas of greater anthropogenic impact. Results from this study improve our understanding of the occurrence and biological uptake of microplastics in Lake Mead National Recreation Area, and help fill existing knowledge gaps on microplastics in freshwater environments in the southwestern U.S.

Nevada↗