Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Input”

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

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

At least 1,099 records · Page 61Linked to original sources
USGS2002

Effects of wastewater and combined sewer overflows on water quality in the Blue River basin, Kansas City, Missouri and Kansas, July 1998-October 2000

Samples were collected from 16 base-flow events and a minimum of 10 stormflow events between July 1998 and October 2000 to characterize the effects of wastewater and combined sewer overflows on water quality in the Blue River Basin, Kansas City, Missouri and Kansas. Waterquality effects were determined by analysis of nutrients, chloride, chemical and biochemical oxygen demand, and suspended sediment samples from three streams (Blue River, Brush Creek, and Indian Creek) in the basin as well as the determination of a suite of compounds known to be indicative of wastewater including antioxidants, caffeine, detergent metabolites, antimicrobials, and selected over-the-counter and prescription pharmaceuticals. Constituent loads were determined for both hydrologic regimes and a measure of the relative water-quality impact of selected stream reaches on the Blue River and Brush Creek was developed. Genetic fingerprint patterns of Escherichia coli bacteria from selected stream samples were compared to a data base of knownsource patterns to determine possible sources of bacteria. Water quality in the basin was affected by wastewater during both base flows and stormflows; however, there were two distinct sources that contributed to these effects. In the Blue River and Indian Creek, the nearly continuous discharge of treated wastewater effluent was the primary source of nutrients, wastewater indicator compounds, and pharmaceutical compounds detected in stream samples. Wastewater inputs into Brush Creek were largely the result of intermittent stormflow events that triggered the overflow of combined storm and sanitary sewers, and the subsequent discharge of untreated wastewater into the creek. A portion of the sediment, organic matter, and associated constituents from these events were trapped by a series of impoundments constructed along Brush Creek where they likely continued to affect water quality during base flow. Concentrations and loads of most wastewater constituents in the Blue River and Indian Creek were significantly greater than in Brush Creek, especially during base flow. However, wastewater indicator compound concentrations were sometimes greater in some Brush Creek stormflow samples. Selected stream reaches along the mid-portion of Brush Creek showed higher effects relative to other sites, primarily because these sites were in impounded reaches with the greatest density of wastewater inputs, or had relatively small drainage areas.

Kansas, Missouri↗
USGS2002

Water-quality and aquatic-community characteristics of selected reaches of the St. Croix River, Minnesota and Wisconsin, 2000

Synoptic sampling was used to determine chemical and biological characteristics of the St. Croix River within a study reach that extended from near Danbury, Wisconsin to the confluence with the Mississippi River at Prescott, Wisconsin. The study was conducted August 7- September 25, 2000 during summer low flow. Dissolved-residue concentrations were found to increase gradually as the river flows downstream, with an abrupt increase downstream of the confluence with the Sunrise River that was primarily attributed to an increase in calcium and magnesium. Dissolved residue concentrations were further augmented by increased yields of chloride and sulfate in the part of the St. Croix Basin between Nevers Dam near St. Croix Falls, Wisconsin and Marine on St. Croix, Minnesota. Nearly all of the nitrogen in transport was in the form of nitrate and organic nitrogen. Organic nitrogen, mainly in particulate form, accounted for most of the gain in total nitrogen load within the study reach. Nitrogen loading to the mainstem indicated relatively uniform nitrogen inputs from the Clam River, Kettle River, and Snake River watersheds. The rate of nitrogen load accrual increased downstream of the confluence with the Sunrise River and in the subreach extending from Nevers Dam through St. Croix Falls to Franconia, Minnesota. Nitrogen load also increased, primarily because of nitrate input, in the part of Lake St. Croix downstream of the confluence with the Kinnickinnic River. Total phosphorus concentrations and loads reflected variations in the amount of particulate phosphorus in transport. Phosphorus loading increased in the part of the St. Croix River that includes Danbury and the confluences of the Yellow River and Clam River. Phosphorus loading also increased downstream of the confluence with the Sunrise River, but the greatest load increase occurred between Nevers Dam and Franconia. Phosphorus load decreased substantially as the river flowed through the pooled reach of Lake St. Croix downstream of Stillwater. Suspended-sediment concentrations were low, ranging from 4.0 to 36 milligrams per liter. The small amount of sediment in transport was reflected in turbidity measurements that ranged from 0.5 to 3.6 Nephelometry Turbidity Units, and transparency tube measurements that were greater than 60 centimeters at all sites. Biological measures of resource quality change in the St. Croix River along its course from Danbury to Prescott. Changes in the biological indicators of resource quality (fish and invertebrate community composition) are most notable just upstream and downstream of the dam at St. Croix Falls, Wisconsin. Aquatic communities in the upper St. Croix River, from near Danbury to near Rush City, Minnesota, indicate minimal physical and chemical disturbance as evidenced by relatively high taxa richness and greater proportions of taxa intolerant to physical and chemical disturbance. In contrast, aquatic communities downstream of the Sunrise River to Marine on St. Croix indicate both physical and chemical disturbance. Resource monitoring, consisting of short-term diagnostic studies, may be needed in parts of the St. Croix River mainstem and tributaries where results from this study indicate constituent loading is greatest and where the aquatic community composition indicates disturbance. Longer-term trend monitoring may be needed to detect physical, chemical and biological responses to natural processes and human activities in the St. Croix River Basin.

Minnesota, Wisconsin↗
USGS2002

SUTRA: A model for 2D or 3D saturated-unsaturated, variable-density ground-water flow with solute or energy transport

SUTRA (Saturated-Unsaturated Transport) is a computer program that simulates fluid movement and the transport of either energy or dissolved substances in a subsurface environment. This upgraded version of SUTRA adds the capability for three-dimensional simulation to the former code (Voss, 1984), which allowed only two-dimensional simulation. The code employs a two- or three-dimensional finite-element and finite-difference method to approximate the governing equations that describe the two interdependent processes that are simulated: 1) fluid density-dependent saturated or unsaturated ground-water flow; and 2) either (a) transport of a solute in the ground water, in which the solute may be subject to: equilibrium adsorption on the porous matrix, and both first-order and zero-order production or decay; or (b) transport of thermal energy in the ground water and solid matrix of the aquifer. SUTRA may also be used to simulate simpler subsets of the above processes. A flow-direction-dependent dispersion process for anisotropic media is also provided by the code and is introduced in this report. As the primary calculated result, SUTRA provides fluid pressures and either solute concentrations or temperatures, as they vary with time, everywhere in the simulated subsurface system. SUTRA flow simulation may be employed for two-dimensional (2D) areal, cross sectional and three-dimensional (3D) modeling of saturated ground-water flow systems, and for cross sectional and 3D modeling of unsaturated zone flow. Solute-transport simulation using SUTRA may be employed to model natural or man-induced chemical-species transport including processes of solute sorption, production, and decay. For example, it may be applied to analyze ground-water contaminant transport problems and aquifer restoration designs. In addition, solute-transport simulation with SUTRA may be used for modeling of variable-density leachate movement, and for cross sectional modeling of saltwater intrusion in aquifers at near-well or regional scales, with either dispersed or relatively sharp transition zones between freshwater and saltwater. SUTRA energy-transport simulation may be employed to model thermal regimes in aquifers, subsurface heat conduction, aquifer thermal-energy storage systems, geothermal reservoirs, thermal pollution of aquifers, and natural hydrogeologic convection systems. Mesh construction, which is quite flexible for arbitrary geometries, employs quadrilateral finite elements in 2D Cartesian or radial-cylindrical coordinate systems, and hexahedral finite elements in 3D systems. 3D meshes are currently restricted to be logically rectangular; in other words, they are similar to deformable finite-difference-style grids. Permeabilities may be anisotropic and may vary in both direction and magnitude throughout the system, as may most other aquifer and fluid properties. Boundary conditions, sources and sinks may be time dependent. A number of input data checks are made to verify the input data set. An option is available for storing intermediate results and restarting a simulation at the intermediate time. Output options include fluid velocities, fluid mass and solute mass or energy budgets, and time-varying observations at points in the system. Both the mathematical basis for SUTRA and the program structure are highly general, and are modularized to allow for straightforward addition of new methods or processes to the simulation. The FORTRAN-90 coding stresses clarity and modularity rather than efficiency, providing easy access for later modifications.

Water-Resources Investigations Report↗
USGS2003

Water quality and the effects of changes in phosphorus loading to Muskellunge Lake, Vilas County, Wisconsin

Muskellunge Lake is a productive, eutrophic lake because of high nutrient loading. Historical data indicate that water quality has only slightly degraded since the early 1970s, possibly because of phosphorus input from effluent from septic systems. A detailed phosphorus budget for the lake indicated that most of the phosphorus comes from natural sources?ground water and surface water flowing through relatively undeveloped areas surrounding the lake. Modeling results indicated that the natural input of phosphorus was sufficient to maintain the lake's eutrophic condition. Analysis of sediment cores confirmed that only small changes in nutrient and algal concentrations have occurred over the past 100 years; however, the analysis indicated that the macrophyte community has increased over this time period. The aeration system, installed to alleviate winter anoxia, maintains aerobic conditions throughout the main bays of the lake.

Wisconsin↗
USGS2003

Simulation of net infiltration and potential recharge using a distributed-parameter watershed model of the Death Valley region, Nevada and California

This report presents the development and application of the distributed-parameter watershed model, INFILv3, for estimating the temporal and spatial distribution of net infiltration and potential recharge in the Death Valley region, Nevada and California. The estimates of net infiltration quantify the downward drainage of water across the lower boundary of the root zone and are used to indicate potential recharge under variable climate conditions and drainage basin characteristics. Spatial variability in recharge in the Death Valley region likely is high owing to large differences in precipitation, potential evapotranspiration, bedrock permeability, soil thickness, vegetation characteristics, and contributions to recharge along active stream channels. The quantity and spatial distribution of recharge representing the effects of variable climatic conditions and drainage basin characteristics on recharge are needed to reduce uncertainty in modeling ground-water flow. The U.S. Geological Survey, in cooperation with the Department of Energy, developed a regional saturated-zone ground-water flow model of the Death Valley regional ground-water flow system to help evaluate the current hydrogeologic system and the potential effects of natural or human-induced changes. Although previous estimates of recharge have been made for most areas of the Death Valley region, including the area defined by the boundary of the Death Valley regional ground-water flow system, the uncertainty of these estimates is high, and the spatial and temporal variability of the recharge in these basins has not been quantified. To estimate the magnitude and distribution of potential recharge in response to variable climate and spatially varying drainage basin characteristics, the INFILv3 model uses a daily water-balance model of the root zone with a primarily deterministic representation of the processes controlling net infiltration and potential recharge. The daily water balance includes precipitation (as either rain or snow), snow accumulation, sublimation, snowmelt, infiltration into the root zone, evapotranspiration, drainage, water content change throughout the root-zone profile (represented as a 6-layered system), runoff (defined as excess rainfall and snowmelt) and surface water run-on (defined as runoff that is routed downstream), and net infiltration (simulated as drainage from the bottom root-zone layer). Potential evapotranspiration is simulated using an hourly solar radiation model to simulate daily net radiation, and daily evapotranspiration is simulated as an empirical function of root zone water content and potential evapotranspiration. The model uses daily climate records of precipitation and air temperature from a regionally distributed network of 132 climate stations and a spatially distributed representation of drainage basin characteristics defined by topography, geology, soils, and vegetation to simulate daily net infiltration at all locations, including stream channels with intermittent streamflow in response to runoff from rain and snowmelt. The temporal distribution of daily, monthly, and annual net infiltration can be used to evaluate the potential effect of future climatic conditions on potential recharge. The INFILv3 model inputs representing drainage basin characteristics were developed using a geographic information system (GIS) to define a set of spatially distributed input parameters uniquely assigned to each grid cell of the INFILv3 model grid. The model grid, which was defined by a digital elevation model (DEM) of the Death Valley region, consists of 1,252,418 model grid cells with a uniform grid cell dimension of 278.5 meters in the north-south and east-west directions. The elevation values from the DEM were used with monthly regression models developed from the daily climate data to estimate the spatial distribution of daily precipitation and air temperature. The elevation values were also used to simulate atmosp

Water-Resources Investigations Report↗
USGS2003

Simulation of Temperature, Nutrients, Biochemical Oxygen Demand, and Dissolved Oxygen in the Catawba River, South Carolina, 1996-97

Time-series plots of dissolved-oxygen concentrations were determined for various simulated hydrologic and point-source loading conditions along a free-flowing section of the Catawba River from Lake Wylie Dam to the headwaters of Fishing Creek Reservoir in South Carolina. The U.S. Geological Survey one-dimensional dynamic-flow model, BRANCH, was used to simulate hydrodynamic data for the Branched Lagrangian Transport Model. Waterquality data were used to calibrate the Branched Lagrangian Transport Model and included concentrations of nutrients, chlorophyll a, and biochemical oxygen demand in water samples collected during two synoptic sampling surveys at 10 sites along the main stem of the Catawba River and at 3 tributaries; and continuous water temperature and dissolved-oxygen concentrations measured at 5 locations along the main stem of the Catawba River. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to watertemperature boundary data due to the effect of temperature on reaction kinetics and the solubility of dissolved oxygen. Of the model coefficients, the simulated dissolved-oxygen concentration was most sensitive to the biological oxidation rate of nitrite to nitrate. To demonstrate the utility of the Branched Lagrangian Transport Model for the Catawba River, the model was used to simulate several water-quality scenarios to evaluate the effect on the 24-hour mean dissolved-oxygen concentrations at selected sites for August 24, 1996, as simulated during the model calibration period of August 23 27, 1996. The first scenario included three loading conditions of the major effluent discharges along the main stem of the Catawba River (1) current load (as sampled in August 1996); (2) no load (all point-source loads were removed from the main stem of the Catawba River; loads from the main tributaries were not removed); and (3) fully loaded (in accordance with South Carolina Department of Health and Environmental Control National Discharge Elimination System permits). Results indicate that the 24-hour mean and minimum dissolved-oxygen concentrations for August 24, 1996, changed from the no-load condition within a range of - 0.33 to 0.02 milligram per liter and - 0.48 to 0.00 milligram per liter, respectively. Fully permitted loading conditions changed the 24-hour mean and minimum dissolved-oxygen concentrations from - 0.88 to 0.04 milligram per liter and - 1.04 to 0.00 milligram per liter, respectively. A second scenario included the addition of a point-source discharge of 25 million gallons per day to the August 1996 calibration conditions. The discharge was added at S.C. Highway 5 or at a location near Culp Island (about 4 miles downstream from S.C. Highway 5) and had no significant effect on the daily mean and minimum dissolved-oxygen concentration. A third scenario evaluated the phosphorus loading into Fishing Creek Reservoir; four loading conditions of phosphorus into Catawba River were simulated. The four conditions included fully permitted and actual loading conditions, removal of all point sources from the Catawba River, and removal of all point and nonpoint sources from Sugar Creek. Removing the point-source inputs on the Catawba River and the point and nonpoint sources in Sugar Creek reduced the organic phosphorus and orthophosphate loadings to Fishing Creek Reservoir by 78 and 85 percent, respectively.

South Carolina↗
USGS2003

Variations in sand storage measured at monumented cross sections in the Colorado River between Glen Canyon Dam and Lava Falls Rapid, northern Arizona, 1992-99

Bed elevations were measured at 131 monumented cross sections in the Colorado River between Glen Canyon Dam and Lava Falls Rapid from June 1992 to September 1999 to provide data on channel sand storage. This report documents the location of the 131 monumented cross sections, dates of measurements for all cross sections, methods of data collection and processing, and spatial and temporal variation and variability in changes in cross-sectional area for selected cross sections. Additionally, data were analyzed to determine if changes in sediment storage could be related to main channel flow conditions and tributary sediment inputs. Most of the cross sections showed a limited capacity, both in terms of amount and residence time, to store sediment. Data for 83 of the 131 cross sections were comprehensive and complete, and were used for analyses in this report. This data set is referred to as the primary data set. Of these 83 cross sections, 19 had a net gain in stored sediment, 61 had a net loss of stored sediment, and 3 had no change in stored sediment for the period of data collection, excluding data collected during the high release from Glen Canyon Dam in 1996. A subset of the primary data set consisting of the sections downstream from the Paria and Little Colorado Rivers with measurements made on or nearly on the same day, referred to as the matching-date data set, was used to explore the effects of controlled flows and tributary flows on the changes in cross-sectional area. The matching-date data set consists of data from 57 cross sections. Of these 57 cross sections, 1 had a net gain in stored sediment, 55 had a net loss of stored sediment, and 1 had no change in stored sediment. Results of the analysis did not show that changes in cross-sectional area were strongly related to main channel flow conditions or tributary sediment inputs.

Water-Resources Investigations Report↗
USGS2004

Concentrations of dissolved solids and nutrients in water sources and selected streams of the Santa Ana Basin, California, October 1998 - September 2001

Concentrations of total dissolved solids (TDS) and nutrients in selected Santa Ana Basin streams were examined as a function of water source. The principal water sources are mountain runoff, wastewater, urban runoff, and stormflow. Rising ground water also enters basin streams in some reaches. Data were collected from October 1998 to September 2001 from 6 fixed sites (including a mountain site), 6 additional mountain sites (including an alpine indicator site), and more than 20 synoptic sites. The fixed mountain site on the Santa Ana River near Mentone appears to be a good representative of reference conditions for water entering the basin. TDS can be related to water source. The median TDS concentration in base-flow samples from mountain sites was 200 mg/L (milligrams per liter). Base-flow TDS concentrations from sites on the valley floor typically ranged from 400 to 600 mg/L; base flow to most of these sites is predominantly treated wastewater, with minor contributions of rising ground water and urban runoff. Sparse data suggest that TDS concentrations in urban runoff are about 300 mg/L. TDS concentrations appear to increase on a downstream gradient along the main stem of the Santa Ana River, regardless of source inputs. The major-ion compositions observed in samples from the different sites can be related to water source, as well as to in-stream processes in the basin. Water compositions from mountain sites are categorized into two groups: one group had a composition close to that of the alpine indicator site high in the watershed, and another group had ionic characteristics closer to those in tributaries on the valley floor. The water composition at Warm Creek, a tributary urban indicator site, was highly variable but approximately intermediate to the compositions of the upgradient mountain sites. Water compositions at the Prado Dam and Imperial Highway sites, located 11 miles apart on the Santa Ana River, were similar to one another and appeared to be a mixture of the waters of the upstream sites, Santa Ana River at MWD Crossing, Cucamonga Creek, and Warm Creek. Rainfall usually dilutes stream TDS concentrations. The median TDS concentration in all storm-event discrete samples was 260 mg/L. The median flow-weighted average TDS concentration for stormflow, based on continuous measurement of specific conductance and hydrograph separation of the continuous discharge record, was 190 mg/L. However, stormflow TDS concentrations were variable, and depended on whether the storm was associated with a relatively small or large rainfall event. TDS concentrations in stormflow associated with relatively small events ranged from about 50 to 600 mg/L with a median of 220 mg/L, whereas concentrations in stormflow associated with relatively large events ranged from about 40 to 300 mg/L with a median of 100 mg/L. From the perspective of water managers, the nutrient species of highest concern in Santa Ana Basin streams is nitrate. Most mountain streams had median base-flow concentrations of nitrate below 0.3 mg/L as nitrogen. Nitrate concentrations in both urban runoff and stormflow were near 1 mg/L, which is close to the level found in rainfall for the region. In fact, results from this study suggest that much of the nitrate load in urban storm runoff comes from rainwater. Nitrate concentrations in the Santa Ana River and its major tributaries are highest downstream from wastewater inputs, where median base-flow concentrations of nitrite+nitrate ranged from about 5 to 7 mg/L. About 4 percent of samples collected from sites receiving treated wastewater had nitrate concentrations greater than 10 mg/L. Rising ground water also appears to have high nitrate concentrations (greater than 10 mg/L) in some reaches of the river. Concentrations of other nitrogen species were much lower than nitrate concentrations in base-flow samples. However, storm events increased concentrations and the proportion of organic nitro

Water-Resources Investigations Report↗
USGS2004

Reconnaissance of chemical and biological quality in the Owyhee River from the Oregon State line to the Owyhee Reservoir, Oregon, 2001–02

The Owyhee River drains an extremely rugged and sparsely populated landscape in northern Nevada, southwestern Idaho, and eastern Oregon. Most of the segment between the Oregon State line and Lake Owyhee is part of the National Wild and Scenic Rivers System, and few water-quality data exist for evaluating environmental impacts. As a result, the U.S. Geological Survey, in cooperation with the Bureau of Land Management, assessed this river segment to characterize chemical and biological quality of the river, identify where designated beneficial uses are met and where changes in stream quality occur, and provide data needed to address activities related to environmental impact assessments and Total Maximum Daily Loads. Water-quality issues identified at one or more sites were water temperature, suspended sediment, dissolved oxygen, pH, nutrients, trace elements, fecal bacteria, benthic invertebrate communities, and periphyton communities. Generally, summer water temperatures routinely exceeded Oregon's maximum 7-day average criteria of 17.8 degrees Celsius. The presence of few coldwater taxa in benthic invertebrate communities supports this observation. Suspended-sediment concentrations during summer base flow were less than 10 milligrams per liter (mg/L). Dissolved solids concentrations ranged from 46 to 222 mg/L, were highest during base flow, and tended to increase in a downstream direction. Chemical compositions of water samples indicated that large proportions of upland-derived water extend to the lower reaches of the study area during spring runoff. Dissolved fluoride and arsenic concentrations were highest during base flow and may be a result of geothermal springs discharging to the river. No dissolved selenium was detected. Upstream from the Rome area, spring runoff concentrations of suspended sediment ranged from 0 to 52 mg/L, and all except at the Three Forks site were typically below 20 mg/L. Stream-bottom materials from the North Fork Owyhee River, an area with no mines, were enriched with nine trace elements, which indicates that this basin may be a natural source of these elements. Near Rome, the part of the study area not included in the National Wild and Scenic Rivers System, land-use impacts resulted in elevated populations of Escherichia coli bacteria ( E. coli ) during base flow and elevated concentrations of nitrogen and phosphorus during spring runoff. Sites in this area had the highest numbers of benthic invertebrates; the fewest Ephemeroptera, Plecoptera, and Trichoptera taxa; and the highest Hilsenhoff Biotic Index scores. These results suggest degraded stream quality. Periphyton communities at sites in this area approached nuisance levels and could cause significant dissolved oxygen depletions and pH values that exceed Oregon's recommended criteria. Stream-bottom materials from Jordan Creek were enriched with mercury and manganese, which probably were ultimately caused by past mining in that basin. Below Crooked Creek, elevated suspended sediment concentrations (142 mg/L), phosphorus concentrations (0.23 mg/L), and E. coli populations (370 most probable number per 100 milliliters) during the largest spring runoff event could be the result of inputs at the lower end of Jordan Valley and (or) inputs from Crooked Creek. The New Zealand Mud Snail, a highly competitive gastropod introduced to the Snake River in the 1980s, was collected just downstream from the Crooked Creek confluence.

Idaho;Nevada;Oregon↗
USGS2000

Hydrologic treatments affect gaseous carbon loss From organic soils, Twitchell Island, California, October 1995–December 1997

Subsidence of organic soils in the Sacramento-San Joaquin Delta, California, has increased the potential for levee failure and flooding in the region. Because oxidation of the peat soils is a primary cause of subsidence, reversion of affected lands to wetlands has been proposed as a mitigation tool. To test this hypothesis, three 10 x 10 meter enclosures were built on Twitchell Island in the Delta and managed as different wetland habitats. Emissions of carbon dioxide and methane were measured in situ from October 1995 through December 1997, from the systems that developed under the different water-management treatments. Treatments included a seasonal control (SC) under current island management conditions; reverse flooding (RF), where the land is intentionally flooded from early dry season until midsummer; permanent shallow flooding (F); and a more deeply flooded, open-water (OW) treatment. Hydrologic treatments affected microbial processes, plant community and temperature dynamics which, in turn, affected carbon cycling. Water-management treatments with a period of flooding significantly decreased gaseous carbon emissions compared to the seasonal control. Permanent flooding treatments showed significantly higher methane fluxes than treatments with some period of aerobic conditions. Shallow flooding treatments created conditions that support cattail [Typha species (spp.)] marshes, while deep flooding precluded emergent vegetation. Carbon inputs to the permanent shallow flooding treatment tended to be greater than the measured losses. This suggests that permanent shallow flooding has the greatest potential for managing subsidence of these soils by generating organic substrate more rapidly than is lost through decomposition. Carbon input estimates of plant biomass compared to measurements of gaseous carbon losses indicate the potential for mitigation of subsidence through hydrologic management of the organic soils in the area.

California↗
USGS2002

Standards for the Analysis and Processing of Surface-Water Data and Information Using Electronic Methods

Surface-water computation methods and procedures are described in this report to provide standards from which a completely automated electronic processing system can be developed. To the greatest extent possible, the traditional U. S. Geological Survey (USGS) methodology and standards for streamflow data collection and analysis have been incorporated into these standards. Although USGS methodology and standards are the basis for this report, the report is applicable to other organizations doing similar work. The proposed electronic processing system allows field measurement data, including data stored on automatic field recording devices and data recorded by the field hydrographer (a person who collects streamflow and other surface-water data) in electronic field notebooks, to be input easily and automatically. A user of the electronic processing system easily can monitor the incoming data and verify and edit the data, if necessary. Input of the computational procedures, rating curves, shift requirements, and other special methods are interactive processes between the user and the electronic processing system, with much of this processing being automatic. Special computation procedures are provided for complex stations such as velocity-index, slope, control structures, and unsteady-flow models, such as the Branch-Network Dynamic Flow Model (BRANCH). Navigation paths are designed to lead the user through the computational steps for each type of gaging station (stage-only, stagedischarge, velocity-index, slope, rate-of-change in stage, reservoir, tide, structure, and hydraulic model stations). The proposed electronic processing system emphasizes the use of interactive graphics to provide good visual tools for unit values editing, rating curve and shift analysis, hydrograph comparisons, data-estimation procedures, data review, and other needs. Documentation, review, finalization, and publication of records are provided for with the electronic processing system, as well as archiving, quality assurance, and quality control.

Water-Resources Investigations Report↗
USGS2004

Hydrogeology and simulation of regional ground-water-level declines in Monroe County, Michigan

Observed ground-water-level declines from 1991 to 2003 in northern Monroe County, Michigan, are consistent with increased ground-water demands in the region. In 1991, the estimated ground-water use in the county was 20 million gallons per day, and 80 percent of this total was from quarry dewatering. In 2001, the estimated ground-water use in the county was 30 million gallons per day, and 75 percent of this total was from quarry dewatering. Prior to approximately 1990, the ground-water demands were met by capturing natural discharge from the area and by inducing leakage through glacial deposits that cover the bedrock aquifer. Increased ground-water demand after 1990 led to declines in ground-water level as the system moves toward a new steady-state. Much of the available natural discharge from the bedrock aquifer had been captured by the 1991 conditions, and the response to additional withdrawals resulted in the observed widespread decline in water levels. The causes of the observed declines were explored through the use of a regional ground-water-flow model. The model area includes portions of Lenawee, Monroe, Washtenaw, and Wayne Counties in Michigan, and portions of Fulton, Henry, and Lucas Counties in Ohio. Factors, including lowered water-table elevations because of below average precipitation during the time period (1991 - 2001) and reduction in water supply to the bedrock aquifer because of land-use changes, were found to affect the regional system, but these factors did not explain the regional decline. Potential ground-water capture for the bedrock aquifer in Monroe County is limited by the low hydraulic conductivity of the overlying glacial deposits and shales and the presence of dense saline water within the bedrock as it dips into the Michigan Basin to the west and north of the county. Hydrogeologic features of the bedrock and the overlying glacial deposits were included in the model design. An important step of characterizing the bedrock aquifer was the determination of inputs and outputs of water—leakage from glacial deposits and flows across model boundaries. The imposed demands on the groundwater system create additional discharge from the bedrock aquifer, and this discharge is documented by records and estimates of water use including: residential and industrial use, irrigation, and quarry dewatering. Hydrologic characterization of Monroe County and surrounding areas was used to determine the model boundaries and inputs within the ground-water model. MODFLOW-2000 was the computer model used to simulate ground-water flow. Predevelopment, 1991, and 2001 conditions were simulated with the model. The predevelopment model did not include modern water use and was compared to information from early settlement of the county. The 1991 steady-state model included modern demands on the ground-water system and was based on a significant amount of data collected for this and previous studies. The predevelopment and 1991 simulations were used to calibrate the numerical model. The simulation of 2001 conditions was based on recent data and explored the potential ground-water levels if the current conditions persist. Model results indicate that the ground-water level will stabilize in the county near current levels if the demands imposed during 2001 are held constant.

Michigan↗
USGS1974

Chemical and biological quality of Lake Dicie at Eustis, Florida, with emphasis on the effects of storm runoff

After the construction of a storm drain designed to carry runoff from the southeastern part of the city of Eustis into Lake Dicie, algal blooms occurred in the lake. In order to determine the nature and extent of these blooms, the quality of both the lake and storm runoff into the lake was monitored from March 1971 through June 1973. Surface runoff makes up about 65 percent of the total input to the lake and the storm drain probably contributes about half of the total input. Average concentrations of the major ions in samples of storm runoff collected from the storm drain were not appreciably different from concentrations found in Lake Dicie. However, the storm runoff contained high concentrations of suspended sediment, nitrogen, phosphorus, lead and other trace elements. Most of the sediment and trace elements and much of the phosphorus carried into the lake by storm runoff were trapped in the bottom sediments. The only appreciable change in the quality of the lake since it was first sampled in 1969 is a reduction in the concentration of phosphorus. The amount of inorganic nitrogen and soluble orthophosphate carried into the lake during this investigation was equivalent to about 3,500 pounds (1,600 kilograms) of 6-6-6 commercial fertilizer. Most of these nutrients were taken up by the large phytoplankton population and eventually incorporated into the bottom sediments in Lake Dicie. During much of the year Lake Dicie is thermally stratified and the water near the bottom becomes enriched with nutrients, particularly nitrogen, from the decomposition of algal cells and other organic matter. In the winter months, the water cools and the lake slowly "turns over." The mixing of the nitrogen-rich bottom water with the water in the upper part of the lake where the dissolved oxygen and light penetration are sufficient to support algae often results in explosive algal growth, commonly called a bloom. The two highest concentrations of phytoplankton observed in Lake Dicie during the investigation occurred in December when the lake was not stratified. In Big Bass Lake, a control lake which receives no street runoff, the phytoplankton population is much smaller than in Lake Dicie. Variations in the concentration of phytoplankton appear to be more closely related to rainfall (the major source of nitrogen and phosphorus for Big Bass Lake) than to the seasonal turnover in the lake.

Florida↗
USGS1977

Hydrologic considerations in dewatering and refilling Lake Carlton, Orange and Lake Counties, Florida

Lake Carlton straddles the line between Lake and Orange Counties in central Florida. The 382-acre (155-hectare) lake is highly eutrophic and subject to virtually perpetual algal blooms. The Florida Game and Fresh Water Fish Commission has proposed to restore the lake to a less eutrophic state by dewatering the lake long enough to allow the muck on its bottom to dry and compact. Lake Carlton would be permanently sealed off from Lake Beauclair which presently serves as a source of nutrient enriched water for Lake Carlton. On the assumption that the seasonal rainfall would be normal, and that the dewatering phase would begin on March 1, the predicted time required to dewater the lake at a pumping rate of 50,000 gallons (190 cubic meters) per minute is 21 days. The average rate of pumping required to maintain the lake in a dewatered condition is computed to be 2,400 gallons (9.08 cubic meters) per minute. If pumping is ended May 31, the predicted altitude to which the lake would recover by October 31 as a result of net natural input is 56.2 feet (17.1 meters) above sea level. Raising the lake level to 63 feet (19.2 meters) above sea level by October 31 would require that the net natural input be supplemented at an average rate of about 4,860 gallons (18.4 cubic meters) per minute between May 31 and October 31.

Florida↗
USGS1979

One-dimensional steady-state stream water-quality model

A computer program, based on a one-dimensional mathematical model which predicts the stream water-quality response characteristics from waste source inputs, is described and documented. Variables predicted include dissolved oxygen, biochemical oxygen demand, nitrogen forms, total and fecal-coliform bacteria, orthophosphate-phosphorus, and various conservative substances. The model is based primarily on the well known Streeter-Phelps oxygen-sag equation. Special options of the program include the capability of handling nonpoint source waste inputs and anoxic conditions. The model formulation is based on a steady-state assumption which requires constant flow rate of waste and stream discharges and associated parameters. To achieve a problem solution, each reach of a stream system is broken into a given number of subreaches, generally defined by locations of waste or tributary inflow points. All waste constituents are assumed to be completely mixed within any cross section.

Water-Resources Investigations Report↗
USGS1983

Simulated effects of anticipated coal mining on dissolved solids in selected tributaries of the Yampa River, northwestern Colorado

Identifying cumulative effects of coal mining on dissolved solids downstream from multipe coal-mining operations is particularly important in western basins. The problem of identifying cumulative effects is evident in the Trout Creek drainage, a tributary to the Yampa River in northwestern Colorado, where a number of mines are active and mine expansions are planned. As an evaluation tool, a model was developed and calibrated for the Trout Creek drainage and a reach of the Yampa River main stem. This model uses a series of nodes on the stream network to sum water quantity and quality through the network. The model operates on a monthly basis and uses data from water years 1976 to 1981. Output is mean monthly discharge, dissolved-solids concentration, and dissolved-solids load. Observed data are needed to initiate the model and for model calibration. Some data were extrapolated from records of nearby streamflow-gaging stations. Some nodes within the stream network were for inputs from anticipated mining and were inactive during calibrations. After calibration, these nodes were used to input water discharge at a given dissolved-solids concentration to reflect various future mine configurations. (USGS)

Water-Resources Investigations Report↗
USGS1983

A two-dimensional graphing program for the Tektronix 4050-series graphics computers

A refined, two-dimensional graph-plotting program was developed for use on Tektronix 4050-series graphics computers. Important features of this program include: any combination of logarithmic and linear axes, optional automatic scaling and numbering of the axes, multiple-curve plots, character or drawn symbol-point plotting, optional cartridge-tape data input and plot-format storage, optional spline fitting for smooth curves, and built-in data-editing options. The program is run while the Tektronix is not connected to any large auxiliary computer, although data from files on an auxiliary computer easily can be transferred to data-cartridge for later plotting. The user is led through the plot-construction process by a series of questions and requests for data input. Five example plots are presented to illustrate program capability and the sequence of program operation. (USGS)

Water-Resources Investigations Report↗
USGS1984

Sediment concentrations and loads in the Loxahatchee River estuary, Florida, 1980-82

This study was conducted to estimate the magnitude of sediment loads and the general spatial and temporal patterns of sediment transport in the Loxahatchee River estuary, Florida. Mean concentrations of suspended sediment generally were higher in the Jupiter Inlet area than in the remainder of the embayment area. Concentrations of suspended sediment varied with season and weather conditions. Concentrations in selected tributaries following Tropical Storm Dennis in August 1981 immediately increased as much as 16 times over concentrations before the storm. Suspended-sediment loads from the tributaries were also highly seasonal and storm related. During a 61-day period of above-average rainfall that included Tropical Storm Dennis, 5 major tributaries discharged 926 tons (short) of suspended sediment to the estuary, accounting for 74 percent of the input for the 1981 water year and 49 percent of the input for the 20-month study period. Suspended-sediment loads at Jupiter Inlet and at the mouth of the estuary embayment on both incoming and outgoing tides far exceeded tributary loads, but the direction of long-term, net tidal transport was not determined. (USGS)

Water-Resources Investigations Report↗