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At least 847 records · Page 47Linked to original sources
USGS1979

Streamflow simulation studies of the Hillsborough, Alafia, and Anclote Rivers, west-central Florida

A modified version of the Georgia Tech Watershed Model was applied for the purpose of flow simulation in three large river basins of west- central Florida. The model was calibrated for six streamflow stations located in these basins using 4 years of historical and current rainfall, runoff, and estimated evapotranspiration data. Watersheds modeled range in size from about 70 to 650 square miles. Calibrations were evaluated by comparing the following synthesized and observed data: annual hydrographs for the 1959, 1960, 1973 and 1974 water years, flood hydrographs (maximum daily discharge and flood volume), and long-term annual flood-peak discharges (1950-72). Annual hydrographs, excluding the 1973 water year, were compared using average absolute error in annual runoff and daily flows and correlation coefficients of monthly and daily flows. For stations used in the study, average absolute errors in simulated runoff range from 9 to 21 percent and errors in daily flows range from 48 to 71 percent. Correlation coefficients for monthly flows range from 0.81 to 0.95 and correlation coefficients for daily flows range from 0.68 to 0.87. Correlation coefficients for simulated and observed maximum daily discharges and flood volumes used for calibration range from 0.91 to 0.98 and average standard errors of estimate range from 18 to 45 percent. Cor-relation coefficients for simulated and observed annual flood-peak dis-charges range from 0.60 to 0.74 and average standard errors of estimate range from 33 to 44 percent. The number of flood events used for calibration varies for each streamflow station, but range from 6 to 18. The number of annual flood-peak discharges used also vary but average about 20 for each station. On the basis of these results, it is concluded that flood calibrations have been achieved for stations used in this study; however, because of data limitations, calibrations and prediction errors cannot be completely verified until additional rainfall, runoff, and evapotranspiration data become available.

Florida↗
USGS1985

Analyses of flood-flow frequency for selected gaging stations in South Dakota

Analyses of flood flow frequency were made for 111 continuous-record gaging stations in South Dakota with 10 or more years of record. The analyses were developed using the log-Pearson Type III procedure recommended by the U.S. Water Resources Council. The procedure characterizes flood occurrence at a single site as a sequence of annual peak flows. The magnitudes of the annual peak flows are assumed to be independent random variables following a log-Pearson Type III probability distribution, which defines the probability that any single annual peak flow will exceed a specified discharge. By considering only annual peak flows, the flood-frequency analysis becomes the estimation of the log-Pearson annual-probability curve using the record of annual peak flows at the site. The recorded data are divided into two classes: systematic and historic. The systematic record includes all annual peak flows determined in the process of conducting a systematic gaging program at a site. In this program, the annual peak flow is determined for each and every year of the program. The systematic record is intended to constitute an unbiased and representative sample of the population of all possible annual peak flows at the site. In contrast to the systematic record, the historic record consists of annual peak flows that would not have been determined except for evidence indicating their unusual magnitude. Flood information acquired from historical sources almost invariably refers to floods of noteworthy, and hence extraordinary, size. Although historic records form a biased and unrepresentative sample, they can be used to supplement the systematic record. (Author 's abstract)

Water-Resources Investigations Report↗
USGS1987

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

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

New York↗
USGS1993

Estimation of flood volumes and simulation of flood hydrographs for ungaged small rural streams in Ohio

Methods are presented for estimating flood volumes and simulating flood hydrographs of rural streams in Ohio whose drainage areas are less than 6.5 square miles. The methods were developed to assist engineers in the design of hydraulic structures for which the temporary storage of water is a critical element of the design criteria. Examples of how to use the methods also are presented. Multiple-regression equations were developed to estimate maximum flood volumes of d-hour duration and T-year recurrence interval (dVT). Flood-volume data for all combinations of six durations (1, 2, 4, 8, 16, and 32 hours) and six recurrence intervals (2, 5, 10, 25, 50, and 100 years) were analyzed. The significant independent variables in the resulting 36 equations are drainage area, average annual precipitation, main-channel slope, and forested area. Standard errors of prediction for the 36 dVT equations range from +28 percent to +44 percent. A method is described for simulating flood hydrographs by applying a peak discharge and an estimated basin lagtime to a dimensionless hydrograph. Peak discharge may be estimated from equations in which drainage area, main-channel slope, and storage area are the significant explanatory variables, and average standard errors of prediction range from +33 to +41 percent. An equation is developed for estimating basin lagtime in which main-channel slope, forested area, and storage area are the significant explanatory variables, and the average standard error of prediction is +37 percent. A dimensionless hydrograph developed for use in Georgia was verified for use in Ohio. Step-by-step examples show how to (1) simulate flood hydrographs and compute their volumes, and (2) estimate volume-duration-frequency relations of small ungaged rural streams in Ohio. The volumes estimated by the two methods are compared. Both methods yield similar results for volume estimates of short duration, which are applicable to convective-type storm runoff. The volume-duration-frequency equations can be used to compute volume estimates of long and short duration because the equations are based on maximum-annual-volume data of long and short duration. The dimensionless-hydrograph method is based on flood hydrographs of average duration and cannot be used to compute volume estimates of long duration. Volume estimates of long duration may be considerably greater than volume estimates of short duration and are applicable to runoff from frontal-type storms.

Ohio↗
USGS2015

Methods for estimating flow-duration curve and low-flow frequency statistics for ungaged locations on small streams in Minnesota

Knowledge of the magnitude and frequency of low flows in streams, which are flows in a stream during prolonged dry weather, is fundamental for water-supply planning and design; waste-load allocation; reservoir storage design; and maintenance of water quality and quantity for irrigation, recreation, and wildlife conservation. This report presents the results of a statewide study for which regional regression equations were developed for estimating 13 flow-duration curve statistics and 10 low-flow frequency statistics at ungaged stream locations in Minnesota. The 13 flow-duration curve statistics estimated by regression equations include the 0.0001, 0.001, 0.02, 0.05, 0.1, 0.25, 0.50, 0.75, 0.9, 0.95, 0.99, 0.999, and 0.9999 exceedance-probability quantiles. The low-flow frequency statistics include annual and seasonal (spring, summer, fall, winter) 7-day mean low flows, seasonal 30-day mean low flows, and summer 122-day mean low flows for a recurrence interval of 10 years. Estimates of the 13 flow-duration curve statistics and the 10 low-flow frequency statistics are provided for 196 U.S. Geological Survey continuous-record streamgages using streamflow data collected through September 30, 2012. The study area includes 196 streamgages located within Minnesota and 50 miles beyond the State’s borders in North Dakota, South Dakota, Iowa, and Wisconsin. The study area was divided into five regions that were developed in a previous study using the concept of hydrologic landscape units. Geographic information system software was used to calculate 18 characteristics investigated as potential explanatory variables in regression analyses for each streamgage drainage basin. Trend analyses indicated statistically significant trends in summer 7-day low flows that were not related to precipitation patterns for 19 streamgages. For 16 of these streamgages, the streamflow record was subset using structural change analysis to identify the most recent period of record without a significant trend. The three remaining streamgages with significant trends were excluded from the final analysis because the effective period of record without a significant trend was less than 10 years. Because several streams in this study have zero flow as their minimum reported flow, weighted left-censored regression was used to analyze the flow data in an unbiased manner, with weights based on the number of years of record. A total of 115 regression equations were developed in this study to calculate flow-duration curve and low-flow frequency statistics for ungaged locations in the study area. In addition, data from 25 pairs of streamgages were used to develop drainage-area ratio equations that can be used to estimate streamflow statistics at ungaged locations on streams that have a streamgage in another location. Streamflow statistics estimated using regional regression and drainage-area ratio equations were compared among regions. For regions A, D, and E, drainagearea ratio equations were more accurate than regional regression equations for flows, but regional regression equations were more accurate for high flows. For region F, regional regression equations were consistently more accurate than drainage-area ratio equations. For region BC, the pattern in accuracies of regional regression and drainage-area ratio equations between low flows and high flows was not consistent. Equations developed in this study apply only to stream locations where flows are not substantially affected by regulation, diversion, or urbanization. All equations presented in this study will be incorporated into StreamStats, a web-based geographic information system tool developed by the U.S. Geological Survey. StreamStats allows users to obtain streamflow statistics, basin characteristics, and other information for user-selected locations on streams through an interactive map.

Iowa, Minnesota, North Dakota, South Dakota, Wisco↗
USGS1933

Geology and Ground-Water Resources of the Roswell Artesian Basin, New Mexico

The Roswell artesian basin is in the Pecos Valley in southeastern New Mexico. The investigation, which covered a period of three years, 1925 to 1928, was made for the purpose of determining the available supply of artesian and other ground water within the area. The geologic formations of the region are of the Carboniferous (Permian series) and Quaternary systems. The Permian rocks consist of three units-an upper unit composed chiefly of clay, shale, and sand; a middle unit composed chiefly of limestone; and a lower unit composed chiefly of red beds, gypsum, and anhydrite. Most of the artesian water is obtained from the limestone beds of the middle unit, which has been designated the Picacho limestone. Originally the area of artesian flow comprised 663 square miles; but largely on account of heavy draft upon the artesian reservoir, it decreased to 499 square miles in 1916 and to 425 square miles in 1925. The area irrigated by water derived directly or indirectly from the reservoir amounts to about 60,000 acres. The annual quantity of water derived from wells is about 200,000 acre-feet, and the total discharge at the surface from all sources is about 250,000 acre-feet. Recharge to the reservoir is derived from precipitation that falls on a catchment area of 4,000 square miles west of the artesian area. In 1927 a law was passed by the State of New Mexico declaring underground waters to be public waters and subject to appropriation. This law was declared invalid because of a technicality, and in 1931 a new law was enacted, which furnishes a definite basis for the future regulation of ground waters in the area. The investigation leads to the conclusion that no new land should be placed under irrigation with artesian water, but that the development of shallow ground water should be encouraged. The present decline of the artesian head is slight in comparison with that in earlier years, and there is ample evidence to show that the reservoir annually receives large quantities of recharge and that with proper conservation it will never be completely exhausted.

Water Supply Paper↗
USGS1966

Ground-water resources of selected basins in southwestern Utah

The purpose of this investigation was to correlate the results of past studies in parts of five developed basins in southwestern Utah and to give a unified concept of ground-water conditions in the entire area. The area of investigation comprises about 3,600 square miles in Washington, Iron, Beaver, and Millard Counties, including the five developed basins - Beaver, Cedar City, and Parowan Valleys and the Milford and Beryl-Enterprise districts in Escalante Valley. Annual precipitation in the area ranges from less than 8 inches in parts of the valleys to more than 30 inches in the mountains to the east, with most of the precipitation falling during the October-April period.

Utah↗
USGS2021

Approaches for assessing long-term annual yields of highway and urban runoff in selected areas of California with the Stochastic Empirical Loading and Dilution Model (SELDM)

The California Department of Transportation, commonly known as CalTrans, and other municipal separate storm sewer system permittees in California as well as other State departments of transportation nationwide need information about potential loads and yields (loads per unit area) of constituents of concern in stormwater runoff and discharges from stormwater best management practices (BMPs). Although its National Pollution Discharge Elimination System stormwater permit is focused on areas subject to total maximum daily load (TMDL) regulations, CalTrans builds and maintains BMPs to minimize the adverse effects of roadway runoff on receiving waters throughout the State. This report describes approaches used by the U.S. Geological Survey in cooperation with CalTrans for using the Stochastic Empirical Loading and Dilution Model (SELDM) to assess long-term annual yields of highway and urban runoff in selected areas of California. In this study, a series of regional and local yields were simulated to provide statewide planning-level estimates and more refined TMDL-specific yield values. SELDM was used to analyze 368 State roadway and urban runoff yields for 53 runoff quality constituents. The analyses included 222 random-seed analyses, 60 regional State roadway-runoff analyses, 24 regional urban roadway-runoff analyses, and 62 focused TMDL-area analyses. This report describes approaches and statistics used to analyze available hydrologic and runoff quality data in all analyses. Results for all analyses are provided in the model archive, but only a selected subset of results are presented as examples in this report. State roadway runoff, urban runoff, and BMP discharge yields for total suspended solids, total nitrogen, total phosphorus, and total zinc were selected as examples because they are widespread constituents of concern with substantial amounts of State roadway and urban runoff monitoring data. In this report, a hypothetical basin was specified by using available geographic information to demonstrate use of the State roadway and urban runoff yields to estimate long-term annual stormwater loads from developed areas. Application of these yields to the hypothetical basin indicates that although State-roadway yields may be higher than urban-runoff yields for some constituents, State-roadway loads may be a small proportion of total stormwater loads because State roadways themselves are a small fraction of the total impervious area in such basins. Although application of results from this study may have considerable uncertainty for any particular stormwater outfall, the study does provide robust estimates to support basin-scale runoff-load analyses in California. These analyses also provide estimates for the 12 U.S. Environmental Protection Agency level III ecoregions that are completely or partially within the boundaries of the State of California.

California↗
USGS2016

Suspended sediment delivery to Puget Sound from the lower Nisqually River, western Washington, July 2010–November 2011

On average, the Nisqually River delivers about 100,000 metric tons per year (t/yr) of suspended sediment to Puget Sound, western Washington, a small proportion of the estimated 1,200,000 metric tons (t) of sediment reported to flow in the upper Nisqually River that drains the glaciated, recurrently active Mount Rainier stratovolcano. Most of the upper Nisqually River sediment load is trapped in Alder Lake, a reservoir completed in 1945. For water year 2011 (October 1, 2010‒September 30, 2011), daily sediment and continuous turbidity data were used to determine that 106,000 t of suspended sediment were delivered to Puget Sound, and 36 percent of this load occurred in 2 days during a typical winter storm. Of the total suspended-sediment load delivered to Puget Sound in the water year 2011, 47 percent was sand (particle size >0.063 millimeters), and the remainder (53 percent) was silt and clay. A sediment-transport curve developed from suspended-sediment samples collected from July 2010 to November 2011 agreed closely with a curve derived in 1973 using similar data-collection methods, indicating that similar sediment-transport conditions exist. The median annual suspended-sediment load of 73,000 t (water years 1980–2014) is substantially less than the average load, and the correlation (Pearson’s r = 0.80, p = 8.1E-9, n =35) between annual maximum 2-day sediment loads and normalized peak discharges for the period indicates the importance of wet years and associated peak discharges of the lower Nisqually River for sediment delivery to Puget Sound. The magnitude of peak discharges in the lower Nisqually River generally is suppressed by flow regulation, and relative to other free-flowing, glacier-influenced rivers entering Puget Sound, the Nisqually River delivers proportionally less sediment because of upstream sediment trapping from dams.

Washington↗
USGS2008

Potentiometric Surface of the Upper Floridan Aquifer, West-Central Florida, May 2008

The Floridan aquifer system consists of the Upper and Lower Floridan aquifers separated by the middle confining unit. The middle confining unit and the Lower Floridan aquifer in west-central Florida generally contain highly mineralized water. The water-bearing units containing fresh water are herein referred to as the Upper Floridan aquifer. The Upper Floridan aquifer is the principal source of water in the Southwest Florida Water Management District and is used for major public supply, domestic use, irrigation, and brackish water desalination in coastal communities (Southwest Florida Water Management District, 2000). This map report shows the potentiometric surface of the Upper Floridan aquifer measured in May 2008. The potentiometric surface is an imaginary surface connecting points of equal altitude to which water will rise in tightly-cased wells that tap a confined aquifer system (Lohman, 1979). This map represents water-level conditions near the end of the dry season, when ground-water levels usually are at an annual low and withdrawals for agricultural use typically are high. The cumulative average rainfall of 46.95 inches for west-central Florida (from June 2007 through May 2008) was 5.83 inches below the historical cumulative average of 52.78 inches (Southwest Florida Water Management District, 2008). Historical cumulative averages are calculated from regional rainfall summary reports (1915 to most recent complete calendar year) and are updated monthly by the Southwest Florida Water Management District. This report, prepared by the U.S. Geological Survey in cooperation with the Southwest Florida Water Management District, is part of a semi-annual series of Upper Floridan aquifer potentiometric-surface map reports for west-central Florida. Potentiometric-surface maps have been prepared for January 1964, May 1969, May 1971, May 1973, May 1974, and for each May and September since 1975. Water-level data are collected in May and September each year to show the approximate annual low and high water-level conditions, respectively. Most of the water-level data for this map were collected by the U.S. Geological Survey during the period May 19-23, 2008. Supplemental water-level data were collected by other agencies and companies. A corresponding potentiometric-surface map was prepared for areas east and north of the Southwest Florida Water Management District boundary by the U.S. Geological Survey office in Orlando, Florida (Kinnaman and Dixon, 2008). Most water-level measurements were made during a 5-day period; therefore, measurements do not represent a 'snapshot' of conditions at a specific time, nor do they necessarily coincide with the seasonal low water-level condition.

Scientific Investigations Map↗
USGS2008

Turning population trend monitoring into active conservation: Can we save the cascades frog (Rang cascadae) in the Lassen Region of California?

Monitoring the distribution, population size, and trends of declining species is necessary to evaluate their vulnerability to extinction. It is the responsibility of scientists to alert management professionals of the need for preemptive action if a species approaches imminent, regional extirpation. This is the case with Rana cascadae (Cascades Frog) populations near Lassen Peak From 1993 to 2007, we conducted 1,873 amphibian surveys at 856 sites within Lassen Volcanic National Park and Lassen National Forest, California, USA. These surveys encompassed all R. cascadae habitats: ponds, lakes, meadows, and streams on those lands. We found frogs at only six sites during 14 years of surveys, and obtained one report of a single frog at one additional locality. These sites represented < 1% of the historically suitable habitat within the Lassen region. The number of R. cascadae in the Lassen area has declined since 1991, and one population is now extirpated. We found no evidence of reproduction in most of the populations, and reproduction at all but one of the other sites remained lower than the annual reproductive output of one breeding pair for > 12 years. Causes for the decline remain unclear, but introduced trout, disease, and pesticides are likely factors. We recommend that (1) additional protection for R. cascadae within 50 km of Lassen Peak; (2) investigation of the genetics of R. cascadae in California; (3) research into the role of possible causative factors in these declines; and (4) implementation of a feasibility study to captive breed and reintroduce R. cascadae in the Lassen area. Copyright ?? 2008. Gary Fellers. All rights reserved.

Herpetological Conservation and Biology↗
USGS2015

Benthic response to water quality and biotic pressures in lower south San Francisco Bay, Alviso Slough, and Coyote Creek

Benthic invertebrate communities are monitored because the composition of those communities can effect and be affected by the water quality of an aquatic system. Benthic communities use and sometimes regulate the cycling of essential elements (for example, carbon). Benthic invertebrate taxa may also indicate acutely and chronically stressful environments because they are mostly sessile, accumulate contaminants, and sometimes respond dramatically to oligotrophic as well as eutrophic conditions. Benthic communities can in turn affect water quality by grazing pelagic food resources and increasing the rate of nutrient regeneration through feeding and bioturbating the sediment. South San Francisco Bay is a system dependent on phytoplankton as the base to the food web. Despite abundant nutrients, south San Francisco Bay has had limited phytoplankton production in the last several decades owning to poor light conditions and high grazing losses from the water column by benthic invertebrates. The south San Francisco Bay achieves a balance of biogeochemical conditions in most springs to accommodate a short phytoplankton bloom. This balance has maintained the phytoplankton in south San Francisco Bay at low biomass levels relative to other high-nutrient urban estuaries. The role that benthic invertebrates play in this balance, in these episodic spring events, and in other seasons within the estuary remains of great interest to water-quality and biological resource managers. Our primary objective in this study is to quantify current (2014) benthic-community structure and function in the south San Francisco Bay sloughs and to compare those communities temporally over decadal time scales with a unique long-term dataset. The study area (fig. 1) is inclusive of the area south of the Dumbarton Bridge (DB) including Alviso and Guadalupe Sloughs and Coyote Creek. The following are results highlighted in this report: The benthic communities of Coyote Creek and Alviso, Guadalupe, and Artesian Sloughs were dominated by different organisms but similar functional groups in March, June, and September 2014. Coyote Creek stations (D3 and CC1) had a similar increase in Potamocorbula amurensis biomass followed by a decline in 2014, as was observed annually in the south San Francisco Bay since 1999. The lack of grazing pressure owing to the observed declines in these taxa in 2014 may allow the sloughs to become sources of phytoplankton in spring. Bivalve biomass is elevated in summer and fall relative to the spring and winter except in Artesian Slough, where bivalves did not establish a signifcant presence. Presence of certain species contributes to the prey value of the community to predators. Potamocorbula amurensis is a shallow-burrowing bivalve and hence is easy prey for bottom-feeding predators. In contrast, Macoma petalum is a deposit feeder and can burrow deeper into the substrate than Potamocorbula amurensis , making it harder to be preyed upon. The quantitative importance of such predator-prey relationships on phytoplankton dynamics requires further investigation. There were also more amphipods in the sloughs in March 2014; this group is another potential contributor to the benthic-pelagic biomass balance. There is no observed reason for Artesian Slough to have low bivalve biomass values and high amphipod abundances.

California↗
USGS2007

Effects of Withdrawals on Ground-Water Levels in Southern Maryland and the Adjacent Eastern Shore, 1980-2005

Ground water is the primary source of water supply in most areas of Maryland?s Atlantic Coastal Plain, including Southern Maryland. The counties in this area are experiencing some of the most rapid growth and development in the State, resulting in an increased demand for ground-water production. The cooperative, basic water-data program of the U.S. Geological Survey and the Maryland Geological Survey has collected long-term observations of ground-water levels in Southern Maryland and parts of the Eastern Shore for many decades. Additional water-level observations were made by both agencies beginning in the 1970s, under the Power Plant Research Program of the Maryland Department of Natural Resources. These long-term water levels commonly show significant declines over several decades, which are attributed to ground-water withdrawals. Ground-water-level trends since 1980 in major Coastal Plain aquifers such as the Piney Point-Nanjemoy, Aquia, Magothy, upper Patapsco, lower Patapsco, and Patuxent were compared to water use and withdrawal data. Potentiometric surface maps show that most of the declines in ground-water levels can be directly related to effects from major pumping centers. There is also evidence that deep drawdowns in some pumped aquifers may be causing declines in adjacent, unpumped aquifers. Water-level hydrographs of many wells in Southern Maryland show linear declines in levels year after year, instead of the gradual leveling-off that would be expected as the aquifers equilibrate with pumping. A continual increase in the volumes of water being withdrawn from the aquifers is one explanation for why they are not reaching equilibrium. Although reported ground-water production in Southern Maryland has increased somewhat over the past several decades, the reported increases are often not large enough to account for the observed water-level declines. Numerical modeling simulations indicate that a steady, annual increase in the number of small wells could account for the observed aquifer behavior. Such wells, being pumped at rates below the minimum legal reporting threshold of 10,000 gallons per day, might be the source of the additional withdrawals. More detailed water-use data, especially from domestic wells, central-pivot irrigation wells, and other small users not currently reporting withdrawals to the State, may help to determine the cause of the aquifer declines.

Scientific Investigations Report↗
USGS2022

Evaluation of salinity and nutrient conditions in the Heart River Basin, North Dakota, 1970–2020

The Heart River Basin is predominantly an agricultural basin in western North Dakota and is approximately 3,350 square miles. The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Natural Resources Conservation Service and the Grant County Soil Conservation District, completed a study to assess spatial and temporal patterns of water quality in the Heart River Basin. The purpose of this report is to describe the methods and results of a study to evaluate salinity and nutrients in the Heart River Basin in western North Dakota. Water-quality and streamflow data used in the study were compiled from 1970 to 2020 using the National Water Quality Monitoring Council Water Quality Portal and National Water Information System. Changes in streamflow characteristics were investigated at three sites from 1970 to 2020, and changes in water quality were investigated at four sites from 1974 to 2019. Streamflow analysis indicated decreasing streamflow from 1970 until the late 1990s followed by increasing streamflow through 2020, with the largest increase in the 7-day minimum streamflow or base flow. For the historical water-quality trend period (1974–2019), total dissolved solids, sulfate, sodium, chloride, and sodium adsorption ratio concentrations have increased since the mid-1970s through 2019. Potassium concentrations during the historical period remained mostly constant with some small fluctuations. Calcium and magnesium concentrations increased since the mid-1970s at all sites, except for a decrease at one site between 1974 and 1999. During the recent trend period (1999–2019), increasing concentrations in total dissolved solids, sulfate, sodium, chloride, calcium, magnesium, and sodium adsorption ratios were observed across the Heart River Basin. The magnitude of the increases was smaller at tributary sites compared to main-stem sites. During the recent period, potassium was mostly constant, although small (−0.9 milligram per liter or less) decreases on tributaries and minor (1.3 milligrams per liter) increases on the main-stem sites were detected. Unlike dissolved ion concentrations, significant increases in nutrient concentrations were not detected from 1999 to 2019, but nitrate plus nitrite concentrations most likely decreased upstream from Lake Tschida. Inverse modeling for period 1 (1974–99) in model zone 1 (Heart River reach from site 5 to site 6) had eight reasonable models that indicated the clay mineral-water interactions and dissolution of evaporites control the geochemistry. Results of the inverse modeling for period 2 (1999–2019) in model zone 1 also had eight reasonable models that indicated that the dissolution of evaporites was the major geochemical control. Results of the geochemical modeling for period 1 (1974–99) in model zone 2 (Heart River and Sweetbriar Creek reach from sites 20 and 21 to site 22) produced seven reasonable models, and the geochemical control of the system was the dissolution of sulfate evaporite minerals. Geochemical modeling results for period 2 (1999–2019) in model zone 2 produced 11 reasonable models and was also controlled by the dissolution of sulfate evaporite minerals. Differences between the two model zones indicated that geology controls some of the water-quality changes in the Heart River Basin. Loads were estimated for total dissolved solids, sulfate, sodium, and chloride and total phosphorus. Annual loads estimated for the Heart River from 2013 through 2020 at the Heart River site upstream from Lake Tschida (site 5) and near Mandan (site 22) were generally greatest in 2014 and least in 2016 for total dissolved solids, sulfate, sodium, and chloride. Most of the annual loads of total dissolved solids, sulfate, sodium, and chloride are delivered in March through July in the Heart River at these sites and are likely from snowmelt and spring and summer rains. The mean annual yields of total dissolved solids and sodium from 2013 to 2020 generally were largest in Big Muddy Creek (site 18), whereas yields of sulfate and chloride were largest at Sweetbriar Creek (site 21) compared to the other selected sites in the Heart River Basin. Larger yields of total dissolved solids, sulfate, sodium, and chloride at sites located on Big Muddy Creek and Sweet Briar Creek in the lower Heart River Basin were likely a result of differences in geology and soils upstream from the selected sites. A mass balance of total dissolved solids, sulfate, sodium, and chloride was estimated for the lower Heart River Basin, specifically the reach below Lake Tschida to Mandan (site 7 to site 22). Intervening flow was the largest contributor to the dissolved ion loads in the lower Heart River Basin and is an important part of understanding the transport of dissolved ions in the basin. The intervening load can include groundwater discharge, irrigation return flow, local runoff, and input from smaller ephemeral tributaries. Tributaries in the lower Heart River Basin contributed portions of the total dissolved solids, sulfate, sodium, and chloride loads at the Heart River near Mandan (site 22) that generally were proportional to the streamflow contributions. Annual loads for total phosphorus between 2013 and 2020 at the Heart River site upstream from Lake Tschida (site 5) and near Mandan (site 22) generally were largest in 2019 and smallest in 2016. Most of the total phosphorus loads for main-stem sites 5 and 22 were transported in March, April, and June, likely from snowmelt and early summer rains. The mean annual yields of total phosphorus for 2013–20 were largest on the main-stem site upstream from Lake Tschida (site 5) and Sweetbriar Creek (site 21), whereas the smallest yields were in Big Muddy Creek (site 18). Much of the phosphorus that enters Lake Tschida from the upper basin does not get transported downstream to the lower basin, and much of the phosphorus in the lower basin was attributed to intervening flow.

North Dakota↗
USGS2009

Potentiometric Surface of the Upper Floridan Aquifer, West-Central Florida, September 2008

The Floridan aquifer system consists of the Upper and Lower Floridan aquifers separated by the middle confining unit. The middle confining unit and the Lower Floridan aquifer in west-central Florida generally contain highly mineralized water. The water-bearing units containing fresh water are herein referred to as the Upper Floridan aquifer. The Upper Floridan aquifer is the principal source of water in the Southwest Florida Water Management District and is used for major public supply, domestic use, irrigation, and brackish water desalination in coastal communities (Southwest Florida Water Management District, 2000). This map report shows the potentiometric surface of the Upper Floridan aquifer measured in September 2008. The potentiometric surface is an imaginary surface connecting points of equal altitude to which water will rise in tightly-cased wells that tap a confined aquifer system (Lohman, 1979). This map represents water-level conditions near the end of the wet season, when ground-water levels usually are at an annual high and withdrawals for agricultural use typically are low. The cumulative average rainfall of 50.63 inches for west-central Florida (from October 2007 through September 2008) was 2.26 inches below the historical cumulative average of 52.89 inches (Southwest Florida Water Management District, 2008). Historical cumulative averages are calculated from regional rainfall summary reports (1915 to most recent complete calendar year) and are updated monthly by the Southwest Florida Water Management District. This report, prepared by the U.S. Geological Survey in cooperation with the Southwest Florida Water Management District, is part of a semi-annual series of Upper Floridan aquifer potentiometric-surface map reports for west-central Florida. Potentiometric-surface maps have been prepared for January 1964, May 1969, May 1971, May 1973, May 1974, and for each May and September since 1975. Water-level data are collected in May and September each year to show the approximate annual low and high water-level conditions, respectively. Most of the water-level data for this map were collected by the U.S. Geological Survey during the period September 15-19, 2008. Supplemental water-level data were collected by other agencies and companies. A corresponding potentiometric-surface map was prepared for areas east and north of the Southwest Florida Water Management District boundary by the U.S. Geological Survey office in Orlando, Florida (Kinnaman and Dixon, 2009). Most water-level measurements were made during a 5-day period; therefore, measurements do not represent a 'snapshot' of conditions at a specific time, nor do they necessarily coincide with the seasonal high water-level condition.

Scientific Investigations Map↗
USGS1979

Annual peak discharges from small drainage areas in Montana through September 1978

Annual peak stage and discharge data have been collected and tabulated for crest-stage gaging sites in Montana. The crest-stage program was begun in July 1955 to investigate the magnitude and frequency of floods from small drainage areas. The program has expanded from 45 crest-stage gaging stations initially to 173 stations maintained in 1978. Data are tabulated for the period of record. (Woodard-USGS)

Open-File Report↗
USGS2006

Hydrologic requirements of and consumptive ground-water use by riparian vegetation along the San Pedro River, Arizona

This study is a coordinated effort by the U.S. Geological Survey (USGS), the U.S. Department of Agriculture, Agricultural Research Service (USDA ARS), and Arizona State University, with assistance from the U.S. Army Corps of Engineers, the University of Wyoming, and the University of Arizona. The specific objectives of the study were: to determine the water needs of riparian vegetation through the riparian growing season and throughout the SPRNCA to ensure its long-term ecological integrity; to quantify the total water use of riparian vegetation within the SPRNCA; and to determine the source of water used by key riparian plant species within the SPRNCA. To meet these objectives, the study was divided into three elements: (1) a characterization of the status and variability of hydrologic factors within the riparian system (USGS), (2) a riparian biohydrology study to relate spatial and temporal aspects of riparian changes and condition to the hydrologic variables (Arizona State University), and (3) a water-use evapotranspiration (ET) study to quantify annual consumptive ground-water use by riparian transpiration and direct evaporation from the stream channel (USDA ARS) in cooperation with the U.S. Army Corps of Engineers, the University of Wyoming, and the University of Arizona. Twenty-six sites within the SPRNCA were selected for collection of vegetation data from three primary streamflow regimes (perennial, intermittent-wet, intermittent-dry), which include the principal vegetation communities. Detailed hydrologic-condition data were collected at a subset of 16 of these sites, called the SPRNCA biohydrology sites. Water-use and water-source data were collected at a subset of 5 of the 16 biohydrology sites. Vegetation data also were collected at supplemental sites within the SPRNCA boundary in the Upper San Pedro Basin and in the Lower San Pedro Basin. In addition to information about vegetation and geomorphic conditions, hydrologic data collected at the 16 biohydrology sites were used to delineate 14 reaches that were internally homogenous in terms of streamflow hydrology (spatial intermittence of streamflow) and geomorphology (channel sinuosity and flood-plain width). Although this overall study consisted of three elements, the elements were closely coordinated to derive integrated results. Specifically, the connection between water demand, water availability, and riparian functioning represents a synthesis of the study elements. The effects of intra- and inter-annual as well as spatial variability of hydrologic and riparian factors were observed in each of the three study elements.

Arizona↗
USGS2021

Magnitude and frequency of floods in the alluvial plain of the lower Mississippi River, 2017

Annual exceedance probability flows at gaged locations and regional regression equations used to estimate annual exceedance probability flows at ungaged locations were developed by the U.S. Geological Survey, in cooperation with the Mississippi Department of Transportation, to improve flood-frequency estimates at rural streams in the alluvial plain of the lower Mississippi River. These estimates were developed using current geospatial data, analytical methods, and annual peak-flow data through September 2017 at 58 streamgages in the alluvial plain of the lower Mississippi River, including 9 in Mississippi, 35 in Arkansas, 4 in Missouri, and 10 in Louisiana. Annual exceedance probability flows presented in this report incorporate streamflow data through the 2017 water year, 32 additional years of record since the previous study in 1985 of flood magnitude and frequency in the Mississippi portion of the alluvial plain of the lower Mississippi River. Ranges for standard error of prediction, average variance of prediction, and pseudo-R 2 are 45–61 percent, 0.035–0.059 (log cubic feet per second) 2 , and 90–94 percent, respectively.

Arkansas, Illinois, Kentucky, Louisiana, Mississip↗