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At least 1,747 records · Page 97Linked to original sources
USGS2011

Simulation of streamflow, evapotranspiration, and groundwater recharge in the Lower Frio River watershed, south Texas, 1961-2008

The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; the City of Corpus Christi; the Guadalupe-Blanco River Authority; the San Antonio River Authority; and the San Antonio Water System, configured, calibrated, and tested a watershed model for a study area consisting of about 5,490 mi 2 of the Frio River watershed in south Texas. The purpose of the model is to contribute to the understanding of watershed processes and hydrologic conditions in the lower Frio River watershed. The model simulates streamflow, evapotranspiration (ET), and groundwater recharge by using a numerical representation of physical characteristics of the landscape, and meteorological and streamflow data. Additional time-series inputs to the model include wastewater-treatment-plant discharges, surface-water withdrawals, and estimated groundwater inflow from Leona Springs. Model simulations of streamflow, ET, and groundwater recharge were done for various periods of record depending upon available measured data for input and comparison, starting as early as 1961. Because of the large size of the study area, the lower Frio River watershed was divided into 12 subwatersheds; separate Hydrological Simulation Program-FORTRAN models were developed for each subwatershed. Simulation of the overall study area involved running simulations in downstream order. Output from the model was summarized by subwatershed, point locations, reservoir reaches, and the Carrizo-Wilcox aquifer outcrop. Four long-term U.S. Geological Survey streamflow-gaging stations and two short-term streamflow-gaging stations were used for streamflow model calibration and testing with data from 1991-2008. Calibration was based on data from 2000-08, and testing was based on data from 1991-99. Choke Canyon Reservoir stage data from 1992-2008 and monthly evaporation estimates from 1999-2008 also were used for model calibration. Additionally, 2006-08 ET data from a U.S. Geological Survey meteorological station in Medina County were used for calibration. Streamflow and ET calibration were considered good or very good. For the 2000-08 calibration period, total simulated flow volume and the flow volume of the highest 10 percent of simulated daily flows were calibrated to within about 10 percent of measured volumes at six U.S. Geological Survey streamflow-gaging stations. The flow volume of the lowest 50 percent of daily flows was not simulated as accurately but represented a small percent of the total flow volume. The model-fit efficiency for the weekly mean streamflow during the calibration periods ranged from 0.60 to 0.91, and the root mean square error ranged from 16 to 271 percent of the mean flow rate. The simulated total flow volumes during the testing periods at the long-term gaging stations exceeded the measured total flow volumes by approximately 22 to 50 percent at three stations and were within 7 percent of the measured total flow volumes at one station. For the longer 1961-2008 simulation period at the long-term stations, simulated total flow volumes were within about 3 to 18 percent of measured total flow volumes. The calibrations made by using Choke Canyon reservoir volume for 1992-2008, reservoir evaporation for 1999-2008, and ET in Medina County for 2006-08, are considered very good. Model limitations include possible errors related to model conceptualization and parameter variability, lack of data to better quantify certain model inputs, and measurement errors. Uncertainty regarding the degree to which available rainfall data represent actual rainfall is potentially the most serious source of measurement error. A sensitivity analysis was performed for the Upper San Miguel subwatershed model to show the effect of changes to model parameters on the estimated mean recharge, ET, and surface runoff from that part of the Carrizo-Wilcox aquifer outcrop. Simulated recharge was most sensitive to the changes in the lower-zone ET (LZ

Texas↗
USGS1980

Hydrologic data for urban studies in the Austin, Texas metropolitan area, 1978

Hydrologic investigations of urban watersheds in Texas were begun by the U.S. Geological Survey in 1954. Studies are now in progress in Austin, Dallas, Dallas County, Fort Worth, Houston, and San Antonio. The Geological Survey, in cooperation with the Texas Department of Water Resources, began hydrologic studies in the Austin urban area in 1954. In cooperation with the city of Austin, the program was expanded in 1975 to include additional streamflow and rainfall gaging stations and the collection of water-quality data. In 1978, the program was expanded to include a ground-water resources study of the South Austin metropolitan area in the Balcones Fault Zone.

Texas↗
USGS2014

Understanding the hydrologic sources and sinks in the Nile Basin using multisource climate and remote sensing data sets

In this study, we integrated satellite-drived precipitation and modeled evapotranspiration data (2000–2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. Over 2000–2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile Basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual timescales, the Nile Basin storage change is substantial while over longer time periods, it is minimal (<1% of basin precipitation). We also used long-term gridded runoff and river discharge data (1869–1984) to understand the discrepancy in the observed and expected flow along the Nile River. The top three countries that contribute most to the flow are Ethiopia, Tanzania, and Kenya. The study revealed that ∼85% of the runoff generated in the equatorial region is lost in an interstation basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the literature reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is greater (97 km 3 ) than the reported amount (84 km 3 ). Due to the large variations of the reported Nile flow at different locations and time periods, the study results indicate the need for increased hydrometeorological instrumentation of the basin. The study also helped improve our understanding of the spatial dynamics of water sources and sinks in the Nile Basin and identified emerging hydrologic questions that require further attention.

Water Resources Research↗
USGS2006

Hydrologic factors pertinent to ground‐water contamination

Predictions of where and how a fluid waste may travel from disposal site to the water table require detailed information on the physical characteristics, location, and extent of all pervious and impervious materials in the unsaturated zone. Principles concerning the flow system in the unsaturated zone indicate the importance of choice of disposal technique in predicting the time required for the fluid waste to traverse the distance to the water table. With appropriate data on the location, extent, and physical properties of water ‐bearing materials and on the boundaries of the saturated zone flow system, it is possible to analyze the relative merits of a variety of waste disposal techniques and to describe the probable consequences of each. Environments of consolidated rocks, such as granites, sandstones, and limestones, pose problems in addition to those related to unconsolidated or granular porous media in defining the fluid‐flow regimes that involve joint patterns, fracture patterns, solutional openings, and the rock structure. The consequences of ground‐water contamination can be just as damaging to water users as the pollution of surface streams. In fact it can be argued that the consequences are far more damaging because they persist over much longer periods of time after the contaminating source has been eliminated. It would appear prudent, therefore, to guard against contamination of the ground‐water resource in the first instance, rather than to engage in long expensive rehabilitation measures after the damage has been done. In 1960 Graham Walton presented data concerning contamination , by sewage or other man‐made wastes, of surface and underground waters. The circumstances attending the reported incidents of contamination , especially those involving ground‐water supplies, have aided materially in the choice of a few principles and ideas that will identify the role of some significant hydrologic factors in the underground movement of fluid wastes. Walton's discussion of ground‐water contamination refers often to physical settings into which fluid wastes are discharged at or near the land surface into cesspools, tile‐drain fields, and holding ponds. Furthermore, most reported instances of ground‐water contamination have taken place in relatively humid.

Groundwater↗
USGS2011

Taking the pulse of snowmelt: in situ sensors reveal seasonal, event and diurnal patterns of nitrate and dissolved organic matter variability in an upland forest stream

Highly resolved time series data are useful to accurately identify the timing, rate, and magnitude of solute transport in streams during hydrologically dynamic periods such as snowmelt. We used in situ optical sensors for nitrate (NO3 - ) and chromophoric dissolved organic matter fluorescence (FDOM) to measure surface water concentrations at 30 min intervals over the snowmelt period (March 21&ndash;May 13, 2009) at a 40.5 hectare forested watershed at Sleepers River, Vermont. We also collected discrete samples for laboratory absorbance and fluorescence as well as &delta; 18 O&ndash;NO3 - isotopes to help interpret the drivers of variable NO3 - and FDOM concentrations measured in situ. In situ data revealed seasonal, event and diurnal patterns associated with hydrological and biogeochemical processes regulating stream NO3 - and FDOM concentrations. An observed decrease in NO3 - concentrations after peak snowmelt runoff and muted response to spring rainfall was consistent with the flushing of a limited supply of NO3 - (mainly from nitrification) from source areas in surficial soils. Stream FDOM concentrations were coupled with flow throughout the study period, suggesting a strong hydrologic control on DOM concentrations in the stream. However, higher FDOM concentrations per unit streamflow after snowmelt likely reflected a greater hydraulic connectivity of the stream to leachable DOM sources in upland soils. We also observed diurnal NO3 - variability of 1&ndash;2 &mu;mol l -1 after snowpack ablation, presumably due to in-stream uptake prior to leafout. A comparison of NO3 - and dissolved organic carbon yields (DOC, measured by FDOM proxy) calculated from weekly discrete samples and in situ data sub-sampled daily resulted in small to moderate differences over the entire study period (-4 to 1% for NO3 - and -3 to -14% for DOC), but resulted in much larger differences for daily yields (-66 to +27% for NO3 - and -88 to +47% for DOC, respectively). Despite challenges inherent in in situ sensor deployments in harsh seasonal conditions, these data provide important insights into processes controlling NO3 - and FDOM in streams, and will be critical for evaluating the effects of climate change on snowmelt delivery to downstream ecosystems.

Vermont↗
USGS2012

Fluid geochemistry of Yucca Mountain and vicinity

Yucca Mountain, a site in southwest Nevada, has been proposed for a deep underground radioactive waste repository. An extensive database of geochemical and isotopic characteristics has been established for pore waters and gases from the unsaturated zone, perched water, and saturated zone waters in the Yucca Mountain area. The development of this database has been driven by diverse needs of the Yucca Mountain Project, especially those aspects of the project involving process modeling and performance assessment. Water and gas chemistries influence the sorption behavior of radionuclides and the solubility of the radionuclide compounds that form. The chemistry of waters that may infiltrate the proposed repository will be determined in part by that of water present in the unsaturated zone above the proposed repository horizon, whereas pore-water compositions beneath the repository horizon will influence the sorption behavior of the radionuclides transported toward the water table. However, more relevant to the discussion in this chapter, development and testing of conceptual flow and transport models for the Yucca Mountain hydrologic system are strengthened through the incorporation of natural environmental tracer data into the process. Chemical and isotopic data are used to establish bounds on key hydrologic parameters and to provide corroborative evidence for model assumptions and predictions. Examples of specific issues addressed by these data include spatial and temporal variability in net fluxes, the role of faults in controlling flow paths, fracture-matrix interactions, the age and origin of perched water, and the distribution of water traveltimes.

Nevada↗
USGS1995

Numerical simulation of ground-water flow in basin-fill material in Salt Lake Valley, Utah

A three-dimensional, finite-difference, numerical model was developed to simulate ground-water flow in the basin-fill material in Salt Lake Valley, Utah. The model was calibrated to steady-state and transient-state conditions. The steady-state simulation was developed and calibrated using hydrologic data defining average conditions for 1968. The transient-state simulation was developed and calibrated using hydrologic data from 1969-91. Areally the model grid is 94 rows by 62 columns, with each cell 0.35 mile on a side. Vertically, the aquifer system is divided into seven layers. The model simulates recharge to the basin-fill ground-water flow system from (1) consolidated rock, (2) streams and canals, (3) precipitation on the valley floor, (4) irrigated land, (5) reservoirs and evaporation ponds in the southwestern part of the valley, and (6) underflow at Jordan Narrows. Estimated discharge to wells, canals, and springs is incorporated in the model. During simulation, the model computes (1) ground-water flow to and seepage from the Jordan River and the lower reaches of its principal tributaries, (2) recharge from consolidated rock at the northern end of the Oquirrh Mountains, (3) discharge to drains, and (4) discharge by evapotranspiration. During steady-state calibration, calibration variables were adjusted within probable ranges to minimize differences between model-computed and measured water levels, model-computed and estimated ground-water discharge to the Jordan River, and simulated and measured vertical hydraulic gradients. The transient-state simulation was calibrated to measured water-level changes and estimated annual gains in the Jordan River.

Utah↗
USGS1970

Quality of surface water in the Bear River basin, Utah, Wyoming and Idaho

Water-quality data have been collected intermittently at several sites in the Bear River basin since 1947. Because the Bear River flows through three States - Utah, Wyoming, and Idaho - water-quality programs have been confined for the most part within State boundaries. In 1967, the U.S. Geological Survey, as a part of its cooperative program with the Utah Department of Natural Resources, Division of Water Rights, designed a reconnaissance to obtain needed water-quality information for the entire basin. This report presents the results of the data-collection phase of the reconnaissance. Also included in this report are data collected intermittently or periodically prior to the reconnaissance by the U.S. Geological Survey, the U.S. Bureau of Reclamation, and the Federal Water Pollution Control Administration. An interpretive report is being prepared and will be published by the U.S. Geological Survey as a Hydrologic Atlas.

Idaho, Utah, Wyoming↗
USGS1982

Maps showing ground-water conditions in the Bill Williams area, Mohave, Yavapai, and Yuma Counties, Arizona - 1980

The Bill Williams area includes about 3,200 mi 2 in Mohave, Yavapai, and Yuma Counties in west-central Arizona. The west half of the area is in the Basin and Range lowlands water province, and the east half is in the Central high-lands water province (see index map). The Basin and Range lowlands province generally is characterized by high mountains separated by broad valleys filled with deposits that commonly store large amounts of ground water. The Central highlands province consists mostly of rugged mountain masses made up of igneous, metamorphic, and well-consolidated sedimentary rocks that contain little space for the storage of ground water except where highly fractured or faulted. A few small valleys between the mountains contain varying thicknesses of water.-bearing deposits. The area is drained by the Bill Williams River and its major tributaries-the Big Sandy River and the Santa Maria River. Many reaches of the Big Sandy and Santa Maria Rivers and their major tributaries are perennial; the flow is sustained by ground-water discharge (Brown and others, 1978, sheet 2). In the Bill Williams area most of the water used is from ground water, although a small amount of surface water also may be diverted. About 18,000 acre-ft of ground water was withdrawn in 1979 (U.S. Geological Survey, 1981). About 17,000 acre-ft was used for the irrigation of 5,200 acres, and the rest was used for domestic, stock, and public supplies. Most of the irrigated land is in Skull Valley and along lower Kirkland Creek and the Bill Williams River. Only selected wells are shown on the maps in areas of high well density. The hydrologic data on which these maps are based are available, for the most part, in computer-printout form and may be consulted at the Arizona Department of Water Resources, 99 East Virginia, Phoenix, and at U.S. Geological Survey offices in: Federal Building, 301 West Congress Street, Tucson, and Valley Center, Suite 1880, Phoenix. Material from which copies can be made at private expense is available at the Tucson and Phoenix offices of the U.S. Geological Survey.

Arizona↗
USGS1987

Streamflow characteristics of the Colorado River Basin in Utah through September 1981

This report summarizes discharge data and other streamflow characteristics developed from gag ing-station records collected through September 1981 at 337 stations in the Colorado River Basin in Utah. Data also are included for 14 stations in adjacent areas of the bordering states of Arizona, Colorado, and Wyoming (fig. 1). The study leading to this report was done in cooperation with the U.S. Bureau of Land Management, which needs the streamflow data in order to evaluate impacts of mining on the hydrologic system. The report also will be beneficial to other Federal, State, and county agencies and to individuals concerned with water supply and water problems in the Colorado River Basin. The streamflow characteristics in the report could be useful in many water-related studies that involve the following: Definition of baseline-hydrologic conditions; studies of the effects of man's activities on streamflow; frequency analyses of low and high flows; regional analyses of streamflow characteristics; design of water-supply systems; water-power studies; forecasting of stream discharge; time-series analyses of streamflow; design of flood-control structures; stream-pollution studies; and water-chemistry transport studies. The basic data used to develop the summaries in this report are records of daily and peak discharge collected by the U.S. Geological Survey and other Federal agencies. Much of the work of the Geological Survey was done in cooperation with Federal, State, and county agencies. Discharge records included in the report generally were for stations with at least 1 complete water year of record and nearby stations that were on the same stream and had different streamflow characteristics. A water year is a 12-month period ending September 30, and it is designated by the calendar year in which it ends. For streams that have had significant changes in regulation by reservoirs or diversions, the records before and after those changes were used separately to provide streamflow characteristics for each period of homogeneous streamflow and to show the change in the characteristics. Summaries for annual peak discharge are included only for stations with 5 or more years of data. The summaries of annual lowest and highest mean-discharge frequency are reported for stations with 10 or more years of daily-discharge record and for which computer-generated frequency curves provided a reasonable fit of the plotted data.

Utah↗
USGS2022

Occurrence of water and thermogenic gas from oil-bearing formations in groundwater near the Orcutt Oil Field, California, USA

Study region Santa Barbara County, California, USA. Study focus To analyze a wide array of newly collected chemical, isotopic, dissolved gas, and age dating tracers in conjunction with historical data from groundwater and oil wells to determine if water and/or thermogenic gas from oil-bearing formations have mixed with groundwater in the Orcutt Oil Field and surrounding area. New hydrological insights for the region Three of 15 groundwater samples had compositions indicating potential mixing with water and/or thermogenic gas from oil-bearing formations. Relevant indicators included salinity tracers (TDS, Cl, Br), NH 3, DOC, enriched δ 13 C-DIC, δ 2 H-CH 4 , δ 13 C-CH 4 , and δ 13 C-C 2 H 6 values, and trace amounts of C3-C5 gas. The potential sources/pathways for oil-bearing formation water and/or thermogenic gas in groundwater overlying and adjacent to the Orcutt Oil Field include: (1) upward movement from formations developed for oil production due to: (a) natural migration; or (b) anthropogenic activity such as injection and/or movement along wellbores; and (2) oil and gas shows in overlying non-producing oil-bearing formations. Groundwater age tracers, elevated 4 He concentrations, and isotopic compositions of noble gases indicated legacy produced water ponds were not a source. This phase of the study relied on samples and data from existing infrastructure. Additional data on potential end-member compositions from new and existing wells and assessments of potential vertical head gradients and pathways between oil and groundwater zones may yield additional insight.

California↗
USGS2006

Simulation of Water Levels and Salinity in the Rivers and Tidal Marshes in the Vicinity of the Savannah National Wildlife Refuge, Coastal South Carolina and Georgia

The Savannah Harbor is one of the busiest ports on the East Coast of the United States and is located downstream from the Savannah National Wildlife Refuge, which is one of the Nation?s largest freshwater tidal marshes. The Georgia Ports Authority and the U.S. Army Corps of Engineers funded hydrodynamic and ecological studies to evaluate the potential effects of a proposed deepening of Savannah Harbor as part of the Environmental Impact Statement. These studies included a three-dimensional (3D) model of the Savannah River estuary system, which was developed to simulate changes in water levels and salinity in the system in response to geometry changes as a result of the deepening of Savannah Harbor, and a marsh-succession model that predicts plant distribution in the tidal marshes in response to changes in the water-level and salinity conditions in the marsh. Beginning in May 2001, the U.S. Geological Survey entered into cooperative agreements with the Georgia Ports Authority to develop empirical models to simulate the water level and salinity of the rivers and tidal marshes in the vicinity of the Savannah National Wildlife Refuge and to link the 3D hydrodynamic river-estuary model and the marsh-succession model. For the development of these models, many different databases were created that describe the complexity and behaviors of the estuary. The U.S. Geological Survey has maintained a network of continuous streamflow, water-level, and specific-conductance (field measurement to compute salinity) river gages in the study area since the 1980s and a network of water-level and salinity marsh gages in the study area since 1999. The Georgia Ports Authority collected water-level and salinity data during summer 1997 and 1999 and collected continuous water-level and salinity data in the marsh and connecting tidal creeks from 1999 to 2002. Most of the databases comprise time series that differ by variable type, periods of record, measurement frequency, location, and reliability. Understanding freshwater inflows, tidal water levels, and specific conductance in the rivers and marshes is critical to enhancing the predictive capabilities of a successful marsh succession model. Data-mining techniques, including artificial neural network (ANN) models, were applied to address various needs of the ecology study and to integrate the riverine predictions from the 3D model to the marsh-succession model. ANN models were developed to simulate riverine water levels and specific conductance in the vicinity of the tidal marshes for the full range of historical conditions using data from the river gaging networks. ANN models were also developed to simulate the marsh water levels and pore-water salinities using data from the marsh gaging networks. Using the marsh ANN models, the continuous marsh network was hindcasted to be concurrent with the long-term riverine network. The hindcasted data allow ecologists to compute hydrologic parameters?such as hydroperiods and exposure frequency?to help analyze historical vegetation data. To integrate the 3D hydrodynamic model, the marsh-succession model, and various time-series databases, a decision support system (DSS) was developed to support the various needs of regulatory and scientific stakeholders. The DSS required the development of a spreadsheet application that integrates the database, 3D hydrodynamic model output, and ANN riverine and marsh models into a single package that is easy to use and can be readily disseminated. The DSS allows users to evaluate water-level and salinity response for different hydrologic conditions. Savannah River streamflows can be controlled by the user as constant flow, a percentage of historical flows, a percentile daily flow hydrograph, or as a user-specified hydrograph. The DSS can also use output from the 3D model at stream gages near the Savannah National Wildlife Refuge to simulate the effects in the tidal marshes. The DSS is distributed with a two-dimensional (

Georgia, South Carolina↗
USGS2003

Predicting changes in hydrologic retention in an evolving semi-arid alluvial stream

Hydrologic retention of solutes in hyporheic zones or other slowly moving waters of natural channels is thought to be a significant control on biogeochemical cycling and ecology of streams. To learn more about factors affecting hydrologic retention, we repeated stream-tracer injections for 5 years in a semi-arid alluvial stream (Pinal Creek, Ariz.) during a period when streamflow was decreasing, channel width increasing, and coverage of aquatic macrophytes expanding. Average stream velocity at Pinal Creek decreased from 0.8 to 0.2 m/s, average stream depth decreased from 0.09 to 0.04 m, and average channel width expanded from 3 to 13 m. Modeling of tracer experiments indicated that the hydrologic retention factor ( R h ), a measure of the average time that solute spends in storage per unit length of downstream transport, increased from 0.02 to 8 s/m. At the same time the ratio of cross-sectional area of storage zones to main channel cross-sectional area ( A s / A ) increased from 0.2 to 0.8 m 2 /m 2 , and average water residence time in storage zones ( t s ) increased from 5 to 24 min. Compared with published data from four other streams in the US, Pinal Creek experienced the greatest change in hydrologic retention for a given change in streamflow. The other streams differed from Pinal Creek in that they experienced a change in streamflow between tracer experiments without substantial geomorphic or vegetative adjustments. As a result, a regression of hydrologic retention on streamflow developed for the other streams underpredicted the measured increases in hydrologic retention at Pinal Creek. The increase in hydrologic retention at Pinal Creek was more accurately predicted when measurements of the Darcy–Weisbach friction factor were used (either alone or in addition to streamflow) as a predictor variable. We conclude that relatively simple measurements of channel friction are useful for predicting the response of hydrologic retention in streams to major adjustments in channel morphology as well as changes in streamflow.

Advances in Water Resources↗
USGS2003

Hydrogeologic Provinces for California based upon established groundwater basins and watershed polygons

Ten hydrogeologic provinces of California are represented by a region- class feature called 'provinces' within this digital data set. These provinces were identified and defined in the USGS Water Resource Investigation Report (WRIR) 03-4166 (Belitz and others, 2003) titled, 'Framework for a Ground-water Quality Monitoring and Assessment Plan for California'. Hydrogeologic provinces are generalized areas where hydrology and/or geology have similar characteristics. The Southern Cal Islands group was not previously defined as a province in WRIR 03-4166, and is therefore identified as a group in this dataset. These provinces were created by grouping polygons from two formally created digital data sets into respective provinces. New polygons were created where necessary. The two digital data set sources consisted of watershed polygons (calwater) and groundwater basin polygons (gw_basins) compiled to create an original publication of hydrogeologic province boundaries in the form of a region-class within the data set. By symbolizing on the region- class, the user can view the ten hydrogeologic provinces and one grouped province in their simplest representation, without watershed and ground- water basin boundaries obscuring the province areas. Original polygons for both the watershed data set and the ground-water basin data set were retained as much as possible.

Open-File Report↗
USGS2007

Habitat and hydrology: Assessing biological resources of the Suwannee River Estuarine system

The U.S. Geological Survey conducted a pilot integrated-science study during 2002 and 2003 to map, describe, and evaluate benthic and emergent habitats in the Suwannee River Estuary on the Gulf Coast of Florida. Categories of aquatic, emergent, and terrestrial habitats were determined from hyperspectral imagery and integrated with hydrologic data to identify estuarine fish habitats. Maps of intertidal and benthic habitat were derived from 12-band, 4-m resolution hyperspectral imagery acquired in September 2002. Hydrologic data were collected from tidal creeks during the winter of 2002-03 and the summer-fall of 2003. Fish were sampled from tidal creeks during March 2003 using rivulet nets, throw traps, and seine nets. Habitat characteristics, hydrologic data, and fish assemblages were compared for tidal creeks north and south of the Suwannee River. Tidal creeks north of the river had more shoreline edge and shallow habitat than creeks to the south. Tidal creeks south of the river were generally of lower salinity (fresher) and supported more freshwater marsh and submerged aquatic vegetation. The southern creeks tended to be deeper but less sinuous than the northern creeks. Water quality and inundation were evaluated with hydrologic monitoring in the creeks. In-situ gauges, recording pressure and temperature, documented a net discharge of brackish to saline groundwater into the tidal creeks with pronounced flow during low tide. Groundwater flow into the creeks was most prominent north of the river. Combined fish-sampling results showed an overall greater abundance of organisms and greater species richness in the southern creeks, nominally attributed a greater range in water quality. Fish samples were dominated by juvenile spot, grass shrimp, bay anchovy, and silverside. The short time frame for hydrologic monitoring and the one-time fish-sampling effort were insufficient for forming definitive conclusions. However, the combination of hyperspectral imagery and hydrologic data identified a range of habitat characteristics and differences in tidal-creek morphology. This endeavor related nearshore benthic habitat and hydrologic conditions with habitat suitability and fish assemblages and provides a template for similar applications in shallow and nearshore estuarine environments.

Florida↗
USGS1982

Methodology for hydrologic evaluation of a potential surface mine: Loblolly Branch basin, Tuscaloosa County, Alabama

Methodology for evaluating premining hydrology and postmining effects of mining and reclamation on the hydrology of an area is presented for a potential mine-permit area of 1,680 acres in the Warrior Coal Field, northwestern Alabama. Information is included on climate, geology, soil-water relations, vegetation, surface water, ground water, and quality of water. Estimation techniques are used to develop data for reconstructed topography, soil-water relations, vegetation cover, peak flows, flow volumes, soil losses, and sediment yields. Streamflow response of the basin is described by the variable-source-area concept; nearly all water moving from slopes flows through coarse-textured soils and unconsolidated sand and gravel deposits that are underlain by an impermeable clay zone. The resultant peak discharges per unit area are small to moderate, and there is very little erosion of slopes or channels. Susceptibility of the soils to compaction by heavy machines and the effects of compaction on soil-water relations are demonstrated. Regression and empirical methods for evaluating streamflow characteristics are compared. Estimates of peak discharges made with four methods are divergent, particularly for recurrence intervals of 2, 5, and 10 years; divergence is less for 25-, 50-, and 100-year discharges. The Universal Soil Loss Equation (USLE) and sediment-delivery ratios are used to estimate sediment yields for various land and cover conditions from premining until 20 years after reclamation would begin. A premining estimate of sediment yield made with the Universal Soil Loss Equation and a sediment-delivery ratio is about 2.5 times larger than an estimate made with the sediment rating curve-flow duration method. Research and data needs are discussed regarding: (1) An improved understanding of the hydrology of small, very ,permeable, upland basins; (2) alternative methods for estimating streamflow and sediment yield of such basins; (3) field evaluation of permeability and erodibility of soils on reclaimed areas; and (4) better understanding of ground-water hydrology and geochemistry of the coal-bearing Pottsville Formation before and after mining.

Alabama↗