USGS Science⌕ Search

SEARCH · USGS Science

Results for “Water-Resources Report”

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 1,189 records · Page 66Linked to original sources
USGS2002

Hydrogeology and simulated effects of ground-water withdrawals from the Floridan aquifer system in Lake County and in the Ocala National Forest and vicinity, north-central Florida

The hydrogeology of Lake County and the Ocala National Forest in north-central Florida was evaluated (1995-2000), and a ground-water flow model was developed and calibrated to simulate the effects of both present day and future ground-water withdrawals in these areas and the surrounding vicinity. A predictive model simulation was performed to determine the effects of projected 2020 ground-water withdrawals on the water levels and flows in the surficial and Floridan aquifer systems. The principal water-bearing units in Lake County and the Ocala National Forest are the surficial and Floridan aquifer systems. The two aquifer systems generally are separated by the intermediate confining unit, which contains beds of lower permeability sediments that confine the water in the Florida aquifer system. The Floridan aquifer system has two major water-bearing zones (the Upper Floridan aquifer and the Lower Floridan aquifer), which generally are separated by one or two less-permeable confining units. The Floridan aquifer system is the major source of ground water in the study area. In 1998, ground-water withdrawals totaled about 115 million gallons per day in Lake County and 5.7 million gallons per day in the Ocala National Forest. Of the total ground water pumped in Lake County in 1998, nearly 50 percent was used for agricultural purposes, more than 40 percent for municipal, domestic, and recreation supplies, and less than 10 percent for commercial and industrial purposes. Fluctuations of lake stages, surficial and Floridan aquifer system water levels, and Upper Floridan aquifer springflows in the study area are highly related to cycles and distribution of rainfall. Long-term hydrographs for 9 lakes, 8 surficial aquifer system and Upper Floridan aquifer wells, and 23 Upper Floridan aquifer springs show the most significant increases in water levels and springflows following consecutive years with above-average rainfall, and significant decreases following consecutive years with below-average rainfall. Long-term (1940-2000) hydrographs of lake and ground-water levels and springflow show a slight downward trend; however, after the early 1960's, this downward trend generally is more pronounced, which corresponds with accumulating rainfall deficits and increased development. The U.S. Geological Survey three-dimensional ground-water flow model MODFLOW-2000 was used to simulate ground-water flow in the surficial and Floridan aquifer systems in Lake County, the Ocala National Forest, and adjacent areas. A steady-state calibration to average 1998 conditions was facilitated by using the inverse modeling capabilities of MODFLOW-2000. Values of hydrologic properties from the calibrated model were in reasonably close agreement with independently estimated values and results from previous modeling studies. The calibrated model generally produced simulated water levels and flows in reasonably close agreement with measured values and was used to simulate the hydrologic effects of projected 2020 conditions. Ground-water withdrawals in the model area have been projected to increase from 470 million gallons per day in 1998 to 704 million gallons per day in 2020. Significant drawdowns were simulated in Lake County from average 1998 to projected 2020 conditions: the average and maximum drawdowns, respectively, were 0.5 and 5.7 feet in the surficial aquifer system, 1.1 and 7.6 feet in the Upper Floridan aquifer, and 1.4 and 4.3 feet in the Lower Floridan aquifer. The largest drawdowns in Lake County were simulated in the southeastern corner of the County and in the vicinities of Clermont and Mount Dora. Closed-basin lakes and wetlands are more likely to be affected by future pumping in these large drawdown areas, as opposed to other areas of Lake County. However, within the Ocala National Forest, drawdowns were relatively small: the average and maximum drawdowns, respectively, were 0.1 and 1.0 feet in the surficial aquifer system, 0.2 and

Water-Resources Investigations Report↗
USGS2002

Ground-water flow simulation and chemical and isotopic mixing equation analysis to determine source contributions to the Missouri River alluvial aquifer in the vicinity of the Independence, Missouri, well field

The city of Independence, Missouri, operates a well field in the Missouri River alluvial aquifer. Steady-state ground-water flow simulation, particle tracking, and the use of chemical and isotopic composition of river water, ground water, and well-field pumpage in a two-component mixing equation were used to determine the source contributions of induced inflow from the Missouri River and recharge to ground water from precipitation in well-field pumpage. Steady-state flow-budget analysis for the simulation-defined zone of contribution to the Independence well field indicates that 86.7 percent of well-field pumpage is from induced inflow from the river, and 6.7 percent is from ground-water recharge from precipitation. The 6.6 percent of flow from outside the simulation-defined zone of contribution is a measure of the uncertainty of the estimation, and occurs because model cells are too large to uniquely define the actual zone of contribution. Flow-budget calculations indicate that the largest source of water to most wells is the Missouri River. Particle-tracking techniques indicate that the Missouri River supplies 82.3 percent of the water to the Independence well field, ground-water recharge from precipitation supplies 9.7 percent, and flow from outside defined zones of contribution supplies 8.0 percent. Particle tracking was used to determine the relative amounts of source water to total well-field pumpage as a function of traveltime from the source. Well-field pumpage that traveled 1 year or less from the source was 8.8 percent, with 0.6 percent from the Missouri River, none from precipitation, and 8.2 percent between starting cells. Well-field pumpage that traveled 2 years or less from the source was 10.3 percent, with 1.8 percent from the Missouri River, 0.2 percent from precipitation, and 8.3 percent between starting cells. Well-field pumpage that traveled 5 years or less from the source was 36.5 percent, with 27.1 percent from the Missouri River, 1.1 percent from precipitation, and 8.3 percent between starting cells. Well-field pumpage that traveled 10 years or less from the source was 42.7 percent, with 32.6 percent from the Missouri River, 1.8 percent from precipitation, and 8.3 percent between starting cells. Well-field pumpage that traveled 25 years or less from the source was 71.9 percent, with 58.9 percent from the Missouri River, 4.7 percent from precipitation, and 8.3 percent between starting cells. Results of chemical (calcium, sodium, iron, and fluoride) and isotopic (oxygen and hydrogen) analyses of water samples collected from the Missouri River, selected monitoring wells around the Independence well field, and combined well-field pumpage were used in a two component mixing equation to estimate the relative amount of Missouri River water in total well-field pumpage. The relative amounts of induced inflow from the Missouri River in well-field pumpage ranged from 49 percent for sodium to 80 percent for calcium, and sensitivities ranged from 0 percent for iron to plus or minus 35 percent for naturally occurring stable isotope ( 18 O). The average of all mixing equation results indicated that 61 percent of well-field pumpage was from induced inflow from the Missouri River. All methods used in the study indicate that more than one-half of the water in well-field pumpage was inflow from the Missouri River. River inflow estimates from ground-water simulation methods are larger and error values are smaller than those using chemical and isotopic data in the mixing equation, although substantial uncertainties exist for both estimation methods. Because of the complex hydrology of the aquifer near the Independence well field, the source estimates using particle tracking probably are the most reliable of the ground-water simulation methods. Mixing equation results are less reliable than those of the ground-water simulation for this study. However, more reliable results can be obtained from the mixing equation by increasing the number of samples and collecting samples for a longer period of time, and during different flow conditions. In the absence of a calibrated ground-water flow simulation, the mixing equation can provide a reasonable estimate of the sources of water to a well field at relatively low cost, if sources of error are clearly understood.

Water-Resources Investigations Report↗
USGS2002

Assessment of possible sources of microbiological contamination and water-quality characteristics of the Jacks Fork, Ozark National Scenic Riverways, Missouri — Phase II

In 1998, an 8-mile reach of the Jacks Fork was included on Missouri's list of impaired waters as required by Section 303(d) of the Federal Clean Water Act. The identified pollutant on the Jacks Fork was fecal coliform bacteria. Potential sources of fecal contamination to the Jacks Fork include a wastewater treatment plant; campground pit-toilet or septic-system effluent; a large commercial, cross-country horseback trail riding facility; canoeists, boaters, and tubers; and cows. The U.S. Geological Survey, in cooperation with the National Park Service, conducted a study to better understand the extent and sources of microbiological contamination within the Jacks Fork from Alley Spring to the mouth, which includes the 8-mile 303(d) reach. Identification of the sources would provide the National Park Service and the State of Missouri with the information needed to craft a solution of abatement, regulation, prevention, and mitigation with the end result being the removal of the Jacks Fork from the 303(d) list. Fifteen sites were sampled from November 1999 through December 2000. An additional site was sampled one time. Samples were collected mostly during base-flow conditions during a variety of nonrecreational and recreational season river uses. Samples were analyzed for selected fecal indicator bacteria, physical properties, nutrients, and wastewater organic compounds. During the sampling period, the whole-body-contact recreation standard for fecal coliform (200 colonies per 100 milliliters of sample) was exceeded at three sites on August 10, 2000, and also at one site on May 11, June 7, and October 3, 2000. Fecal coliform densities and instantaneous loads generally increased from background concentrations at the Eminence site, peaked about 2 river miles downstream, and then decreased until the most downstream site sampled. Generally, the largest densities and loads at sites downstream from Eminence not related to wet-weather flow were observed during a trail ride held August 6 to 12, 2000. A 24-hour sample collection effort was conducted the weekend of July 15 and 16, 2000, to investigate the effect that large numbers of swimmers, canoeists, and tubers had on fecal coliform densities in the Jacks Fork. Five or six samples were collected at six sites between Saturday morning and the following Sunday afternoon. No fecal coliform density at any of the sites sampled exceeded the whole-body-contact recreation standard. Because bacteria survive longer in stream-bed sediments than in water, a source of bacteria in the water column could be from resuspension of accumulated bacteria from streambed sediments. Water and streambed-sediment samples were collected at three sites on August 3, 2000, 1 week before a trail ride and again at three sites on August 8, 2000, during a trail ride. Sixty-five Escherichia coli isolates obtained from water samples collected at 9 sites and 23 Escherichia coli isolates obtained from stream-bed-sediment samples collected at 5 sites were submitted for ribotyping analysis. Samples were collected in 2000 during a variety of nonrecreational and recreational season river uses, including trail rides, canoeing, tubing, and swimming. Of the 65 isolates from water samples, 40 percent were identified as originating from sewage, 29 percent from horse, 11 percent from cow, and 20 percent from an unknown source. Of the 23 isolates from streambed-sediment samples, 39 percent were identified as originating from sewage, 35 percent from horse, 13 percent from cow, and 13 percent from unknown sources. Analysis of physical property (dissolved oxygen, pH, specific conductance, and temperature) and nutrient (dissolved nitrite plus nitrate and total phosphorus) data indicated that overall few statistically significant differences occurred among the main stem sites of the Jacks Fork. A significant increase in total phosphorus concentrations did occur at site 75 immediately downstream from the Eminence Wastewater Treatment Plant, but the effect diminished quickly downstream. Unlike fecal coliform bacteria, most variations in physical property values or nutrient concentrations were related to seasonal changes, time of day the sample was collected, or hydrologic conditions and not to certain recreational activities. Trace quantities of wastewater organic compounds were detected in all waters sampled for these constituents. Two of the compounds were detected in associated laboratory blanks, and other detected compounds have sources other than sewage effluent. The best indicators of municipal or domestic sewage effluent were the non-ionic detergent metabolites (nonylphenol monoethoxylate, octylphenol monoethoxylate, and para-nonylphenol), phenol, and caffeine; but possible sources of these compounds, which were detected in one or more of the samples, could be the numerous campers, swimmers, and canoeists that were present when the samples were collected.

Missouri↗
USGS2003

Periphyton communities in streams of the Ozark Plateaus and their relations to selected environmental factors

During August through September of 1993- 95, 83 periphyton samples were collected at 51 stream sites in the Ozark Plateaus. These sites were categorized into six land-use categories (20 forest, 18 agriculture, 10 mining, 1 urban, 1 urban/ mining, and 1 mix), based on land-use percentages in the basin upstream from the site. Results indicate that periphyton communities of riffles of Ozark streams are affected by natural and land-use related factors. These factors include nutrients, dissolved organic carbon, alkalinity, canopy shading, suspended sediment, embeddedness, stream morphometry, and velocity. For several measures of periphyton communities, statistically significant (p<0.05) differences were found among sites assigned to agriculture, forest, and mining categories. Blue-green algae biovolume, relative abundance of blue-green algae, relative biovolume of diatoms, relative abundance of oligotrophic algae, relative abundance of tolerant taxa, and condition index values were among the measures that differed among land-use categories. Although no environmental factors were significantly correlated with total biovolume, several factors were significantly correlated with biovolume of blue-green algae or biovolume of diatoms. Biovolume of blue-green algae was correlated with percent agriculture land use. Biovolume of diatoms was correlated with orthophosphate, total phosphorus, alkalinity, velocity, embeddedness, and dissolved organic carbon. Diatoms often composed the largest percentage of the biovolume (relative biovolume). Diatom relative biovolume was much higher at mining sites (generally 75 to 90 percent of the total biovolume) than at forest or agriculture sites (generally 15 to 80 percent) and was correlated with several factors, including many land-use related factors. The diatoms Cymbella affinis and Cymbella delicatula and the blue-green algae Calothrix often were the most common (relative abundance and relative biovolume) algae in samples. Detrended correspondence analysis (DCA) and hierarchical cluster analyses results indicated differences among land-use category sites. The DCA results were correlated with a number of land-use related factors and channel morphometry. Grazers (specifically, snails and stonerollers) are related to periphyton biovolume and community composition. Total periphyton and diatom biovolume typically were highest at sites where snail density was lowest. Lower relative abundances of diatoms usually occurred at sites with higher snail densities and stoneroller relative abundances.

Arkansas, Kansas, Missouri, Oklahoma↗
USGS2002

Ground-water, surface-water, and water-chemistry data, Black Mesa Area, northeastern Arizona — 2000–2001, and performance and sensitivity of the 1988 USGS numerical model of the N aquifer

The N aquifer is the major source of water in the 5,400-square-mile area of Black Mesa in northeastern Arizona. Availability of water is an important issue in this area because of continued industrial and municipal use, a growing population, and precipitation of about 6 to 14 inches per year. The monitoring program in Black Mesa has been operating since 1971 and is designed to determine the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, and (5) ground-water chemistry. In 2000, total ground-water withdrawals were 7,740 acre-feet, industrial use was 4,490 acre-feet, and municipal use was 3,250 acre-feet. From 1999 to 2000, total withdrawals increased by 9 percent, industrial use increased by 7 percent, and municipal use increased by 12 percent. From 1999 to 2001, water levels declined in 10 of 15 wells in the unconfined part of the aquifer, and the median change was -0.4 foot. Water levels declined in 8 of 16 wells in the confined part of the aquifer, and the median change was -0.2 foot. From the prestress period (prior to 1965) to 2001, the median water-level change for 33 wells was -17.2 feet. Median water-level changes were -1.2 feet for 15 wells in the unconfined part of the aquifer and -31.0 feet for 18 wells in the confined part. Discharges were measured once in 1999 and once in 2001 at four springs. Discharges decreased by 5 percent and 33 percent at two springs and increased by 3 percent and 81 percent at two springs. For about the past 10 years, discharges did not significantly change in Burro Spring, the unnamed spring near Dennehotso, and Moenkopi School Spring. The record of discharge from a consistent measuring point for Pasture Canyon Spring is too short for statistical analysis of trends. Continuous records of surface-water discharge have been collected from July 1976 to 2000 at Moenkopi Wash, July 1996 to 2000 at Laguna Creek, June 1993 to 2000 at Dinnebito Wash, and April 1994 to 2000 at Polacca Wash. Median flows for November, December, January, and February of each water year were used as an index of ground-water discharge to those streams. There is no significant trend in the median winter flows for Moenkopi Wash from 1977 to 2000. The records for the other three streams are too short for a statistical analysis of trends. The median winter flows for Dinnebito Wash and Polacca Wash, however, appear to have decreased during the last 6 years. There is no apparent trend in the median winter flows for Laguna Creek since 1997. In 2001, water samples were collected from 12 wells and 4 springs and analyzed for selected chemical constituents. Dissolved-solids concentrations ranged from 102 to 628 milligrams per liter. Water samples from 9 of the wells and from the 4 springs had less than 350 milligrams per liter of dissolved solids. Water-chemistry data with sufficient years of record for a statistical analysis of trends over time are available from 7 wells and 4 springs. From about the mid-1980s or early 1990s to 2001 there are no significant trends in the concentrations of dissolved solids, chloride, and sulfate in water samples from 6 of the 7 wells. The concentration of one tested constituent (dissolved solids) in samples from Rocky Ridge PM3 significantly increased from 1990 to 2001. From the late 1980s to 2001, there are no significant trends in the concentrations of dissolved solids, chloride, and sulfate in water samples from Burro Spring, the unnamed spring near Dennehotso, and Pasture Canyon Spring. From 1987 to 2001, concentrations of chloride and sulfate significantly increased in water samples from Moenkopi School Spring and concentrations of dissolved solids did not significantly change. The performance and sensitivity of the 1988 USGS numerical model of the N aquifer were analyzed. The overall performance of the model in steady-state conditions is reasonable for residuals of heads (difference between observed and simulated steady-state heads); 80 percent of the absolute values of residuals are less than 38 feet. Simulated flows are about 40 percent different than estimated flows at two of three discharge areas; however, this comparison is only a rough approximation of performance because the accuracy of the estimated steady-state flows is uncertain. The overall performance of the model for transient conditions is fair for residuals of changes in head (difference between observed and simulated changes in head from steady state to 1999); 80 percent of the absolute values of residuals are less than 31 feet. The model is biased in two areas. In the Tuba City area, simulated changes in head are more negative than observed changes in head; all six residuals are positive, and three residuals are between 75 and 155 feet. In the confined area of the aquifer, observed changes in head are more negative than simulated changes in head; 12 of the 17 residuals are negative, and 8 residuals are between -57 and -20 feet. Analysis of model sensitivity indicates that recharge, transmissivity, and storage coefficient are the most important parameters for estimating heads, changes in heads, and flows. A strong correlation between recharge and transmissivity and a lack of independent and reliable estimates of recharge, transmissivity, and discharge create a uniqueness problem in model calibration. Several models could be constructed and calibrated with different values of recharge or transmissivity and still have similar fits to the observed data. Information from recent data and studies and more advanced modeling techniques could be used to develop a more representative and less uncertain model. Future data collection and studies should focus on obtaining a better definition of recharge, discharge, transmissivity, and storage coefficient.

Arizona↗
USGS2002

Probability distributions of hydraulic conductivity for the hydrogeologic units of the Death Valley regional ground-water flow system, Nevada and California

The use of geologic information such as lithology and rock properties is important to constrain conceptual and numerical hydrogeologic models. This geologic information is difficult to apply explicitly to numerical modeling and analyses because it tends to be qualitative rather than quantitative. This study uses a compilation of hydraulic-conductivity measurements to derive estimates of the probability distributions for several hydrogeologic units within the Death Valley regional ground-water flow system, a geologically and hydrologically complex region underlain by basin-fill sediments, volcanic, intrusive, sedimentary, and metamorphic rocks. Probability distributions of hydraulic conductivity for general rock types have been studied previously; however, this study provides more detailed definition of hydrogeologic units based on lithostratigraphy, lithology, alteration, and fracturing and compares the probability distributions to the aquifer test data. Results suggest that these probability distributions can be used for studies involving, for example, numerical flow modeling, recharge, evapotranspiration, and rainfall runoff. These probability distributions can be used for such studies involving the hydrogeologic units in the region, as well as for similar rock types elsewhere. Within the study area, fracturing appears to have the greatest influence on the hydraulic conductivity of carbonate bedrock hydrogeologic units. Similar to earlier studies, we find that alteration and welding in the Tertiary volcanic rocks greatly influence hydraulic conductivity. As alteration increases, hydraulic conductivity tends to decrease. Increasing degrees of welding appears to increase hydraulic conductivity because welding increases the brittleness of the volcanic rocks, thus increasing the amount of fracturing.

Water-Resources Investigations Report↗
USGS2002

Use of isotopes to identify sources of ground water, estimate ground-water-flow rates, and assess aquifer vulnerability in the Calumet region of northwestern Indiana and northeastern Illinois

Isotope data collected in the Calumet Region of northwestern Indiana and northeastern Illinois, one of the most heavily industrialized regions of the United States, indicated that water in the surficial Calumet aquifer is well mixed. The Calumet aquifer is recharged areally by precipitation and locally may be recharged by surface water. The residence time of ground water in the Calumet aquifer is approximately 5 to 15 years. Ground-water-flow rates through the Calumet aquifer are estimated to be 400 to 2,300 feet per year. The permeable deposits, shallow water table, lack of an overlying confining unit, and proximity to numerous contaminant sources indicate that the Calumet aquifer is vulnerable to contamination. Isotopic data indicate that ground water in the confining unit underlying the Calumet aquifer is derived from a variety of sources that include Lake Michigan, modern precipitation, and discharge from the basal Silurian-Devonian bedrock aquifer. The source and apparent age of the water are variable and appear to be affected locally by various geologic and hydraulic factors. The vertical ground-water-flow rate through the unweathered part of the confining unit is about 0.20 feet per year and is about 6.3 feet per year through the weathered part. The data indicate the weathered part of the confining unit may be more vulnerable to contamination than the unweathered confining unit. Ground water in the basal Silurian-Devonian aquifer is derived from Lake Michigan, glacial-age water, and modern precipitation. Post-1952 recharge has occurred in the vicinity of Stony Island, Ill. Ground-water recharge of the Silurian-Devonian aquifer may be occurring near Calumet Harbor. The Silurian-Devonian aquifer is vulnerable to contamination where the confining unit is thin or absent or where the integrity of the confining unit has been compromised.

Illinois, Indiana↗
USGS2002

Hydrologic conditions in the Bill Williams River National Wildlife Refuge and Planet Valley, Arizona, 2000

During a period of sustained base-flow conditions in the Bill Williams River below Alamo Dam in west central Arizona from March to July 2000, the channel of the river through Planet Valley was dry, and the water table sloped almost due west parallel to the main slope of the flood plain. Water from the river infiltrated into the channel bottom at the head of Planet Valley, moved downgradient in the subsurface, and reappeared in the channel about 0.3 mile downstream from the east boundary of the Bill Williams River National Wildlife Refuge. A river aquifer in hydraulic connection with the Bill Williams River was mapped from a point 6.3 miles upstream from Highway 95 to the upstream end of Planet Valley. Formations that make up the river aquifer in Planet Valley are younger alluvium, older alluviums, and fanglomerate. Total thickness of the river aquifer probably is less than 200 feet in the bedrock canyons to as much as 1,035 feet in Planet Valley. The purpose of this study was to investigate the current hydrologic conditions along the Bill Williams River, which included an inventory of wells within the river aquifer of the Colorado River and in Planet Valley, and to determine the configuration of the water table. A map shows the elevation and configuration of the water table from the east end of Planet Valley to the confluence of the Bill Williams River with Lake Havasu.

Arizona↗
USGS2002

Streamflow and nutrient data for the Yazoo River below Steele Bayou near Long Lake, Mississippi, 1996-2000

Increased nutrient loading to the Gulf of Mexico from off-continent flux has been identified as contributing to the increase in the areal extent of the low dissolved-oxygen zone that develops annually off the Louisiana and Texas coast. The proximity of the Yazoo River Basin in northwestern Mississippi to the Gulf of Mexico, and the intensive agricultural activities in the basin have led to speculation that the Yazoo River Basin contributes a disproportionate amount of nitrogen and phosphorus to the Mississippi River and ultimately to the Gulf of Mexico. An empirical measurement of the flux of nitrogen and phosphorus from the Yazoo Basin has not been possible due to the hydrology of the lower Yazoo River Basin. Streamflow for the Yazoo River below Steele Bayou is affected by backwater from the Mississippi River. Flow at the gage is non-uniform and varying, with bi-directional and reverse flows possible. Streamflow was computed by using remote sensing and acoustic and conventional discharge and velocity measurement techniques. Streamflow from the Yazoo River for the 1996-2000 period accounted for 2.8 percent of the flow of the Mississippi River for the same period. Water samples from the Yazoo River were collected from February 1996 through December 2000 and were analyzed for total nitrogen, nitrate, total phosphorus, and orthophosphorus as part of the U.S. Geological Survey National Water-Quality Assessment Program. These data were used to compute annual loads of nitrogen and phosphorus discharged from the Yazoo River for the period 1996-2000. Annual loads of nitrogen and phosphorus were calculated by two methods. The first method used multivariate regression and the second method multiplied the mean annual concentration by the total annual flow. Load estimates based on the product of the mean annual concentration and the total annual flow were within the 95 percent confidence interval for the load calculated by multivariate regression in 10 of 20 cases. The Yazoo River loads, compared to average annual loads in the Mississippi River, indicated that the Yazoo River was contributing 1.4 percent of the total nitrogen load, 0.7 percent of the nitrate load, 3.4 percent of the total phosphorus load, and 1.6 percent of the orthophosphorus load during 1996 - 2000. The total nitrogen, nitrate, and orthophosphorus loads in the Yazoo River Basin were less than expected, whereas the total phosphorus load was slightly higher than expected based on discharge.

Water-Resources Investigations Report↗
USGS2002

Water quality and geochemical modeling of water at an abandoned coal mine reclaimed With coal combustion by-products

An abandoned coal mine in eastern Ohio was reclaimed with 125 tons per acre of pressurized fluidized bed combustion (PFBC) by-product. Water quality at the site (known as the Fleming site) was monitored for 7 years after reclamation; samples included water from soil-suction lysimeters (interstitial water), wells, and spring sites established downgradient of the application area. This report presents a summary of data collected at the Fleming site during the period September 1994 through June 2001. Additionally, results of geochemical modeling are included in this report to evaluate the potential fate of elements derived from the PFBC by-product. Chemical analyses of samples of interstitial waters within the PFBC by-product application area indicated elevated levels of pH and specific conductance and elevated concentrations of boron, calcium, chloride, fluoride, magnesium, potassium, strontium, and sulfate compared to water samples collected in a control area where traditional reclamation methods were used. Magnesium-to-calcium (Mg:Ca) mole ratios and sulfur-isotope ratios were used to trace the PFBC by-product leachate and showed that little, if any, leachate reached ground water. Concentrations of most constituents in interstitial waters in the application-area decreased during the seven sampling rounds and approached background concentrations observed in the control area; however, median pH in the application area remained above 6, indicating that some acid-neutralizing capacity was still present. Although notable changes in water quality were observed in interstitial waters during the study period, quality of ground water and spring water remained poor. Water from the Fleming site was not potable, given exceedances of primary and secondary Maximum Contaminant Levels (MCLs) for inorganic constituents in drinking water set by the U.S. Environmental Protection Agency. Only fluoride and sulfate, which were found in higher concentrations in application-area interstitial waters than in control-area interstitial waters, could be related to the PFBC by-product. Concentrations of arsenic, lead, and selenium typically were at or below the detection limits (generally 1 or 2 micrograms per liter). Elements detected at elevated concentrations in PFBC by-product application-area interstitial waters were not evident in downgradient ground water or spring water. Dilution of leachate by ground water was confirmed with a mixing model generated by the computer code NETPATH. Additionally, thermodynamic modeling of the chemical composition of water samples by use of the computer code PHREEQC indicated favorable conditions for precipitation of secondary minerals in the unsaturated zone and in aquifer materials. Because of low application rates of PFBC by-product and precipitation and sorption of elements in the unsaturated zone, it is improbable that concentrations of any toxic elements of concern (arsenic, lead, or selenium) will exceed drinking-water standards at this site or other sites where similar volumes of PFBC by-products are used.

Water-Resources Investigations Report↗
USGS2003

Estimating water temperatures in small streams in western Oregon using neural network models

Artificial neural network models were developed to estimate water temperatures in small streams using data collected at 148 sites throughout western Oregon from June to September 1999. The sites were located on 1st-, 2nd-, or 3rd-order streams having undisturbed or minimally disturbed conditions. Data collected at each site for model development included continuous hourly water temperature and description of riparian habitat. Additional data pertaining to the landscape characteristics of the basins upstream of the sites were assembled using geographic information system (GIS) techniques. Hourly meteorological time series data collected at 25 locations within the study region also were assembled. Clustering analysis was used to partition 142 sites into 3 groups. Separate models were developed for each group. The riparian habitat, basin characteristic, and meteorological time series data were independent variables and water temperature time series were dependent variables to the models, respectively. Approximately one-third of the data vectors were used for model training, and the remaining two-thirds were used for model testing. Critical input variables included riparian shade, site elevation, and percentage of forested area of the basin. Coefficient of determination and root mean square error for the models ranged from 0.88 to 0.99 and 0.05 to 0.59 oC, respectively. The models also were tested and validated using temperature time series, habitat, and basin landscape data from 6 sites that were separate from the 142 sites that were used to develop the models. The models are capable of estimating water temperatures at locations along 1st-, 2nd-, and 3rd-order streams in western Oregon. The model user must assemble riparian habitat and basin landscape characteristics data for a site of interest. These data, in addition to meteorological data, are model inputs. Output from the models include simulated hourly water temperatures for the June to September period. Adjustments can be made to the shade input data to simulate the effects of minimum or maximum shade on water temperatures.

Water-Resources Investigations Report↗
USGS2002

Potential effects of structural controls and street sweeping on stormwater loads to the lower Charles River, Massachusetts

The water quality of the lower Charles River is periodically impaired by combined sewer overflows (CSOs) and non-CSO stormwater runoff. This study examined the potential non-CSO load reductions of suspended solids, fecal coliform bacteria, total phosphorus, and total lead that could reasonably be achieved by implementation of stormwater best management practices, including both structural controls and systematic street sweeping. Structural controls were grouped by major physical or chemical process; these included infiltration-filtration (physical separation), biofiltration-bioretention (biological mechanisms), or detention-retention (physical settling). For each of these categories, upper and lower quartiles, median, and average removal efficiencies were compiled from three national databases of structural control performance. Removal efficiencies obtained indicated a wide range of performance. Removal was generally greatest for infiltration-filtration controls and suspended solids, and least for biofiltration-bioretention controls and fecal coliform bacteria. Street sweeping has received renewed interest as a water-quality control practice because of reported improvements in sweeper technology and the recognition that opportunities for implementing structural controls are limited in highly urbanized areas. The Stormwater Management Model that was developed by the U.S. Geological Survey for the lower Charles River Watershed was modified to simulate the effects of street sweeping in a single-family land-use basin. Constituent buildup and washoff variable values were calibrated to observed annual and storm-event loads. Once calibrated, the street sweeping model was applied to various permutations of four sweeper efficiencies and six sweeping frequencies that ranged from every day to once every 30 days. Reduction of constituent loads to the lower Charles River by the combined hypothetical practices of structural controls and street sweeping was estimated for a range of removal efficiencies because of their inherent variability and uncertainty. This range of efficiencies, with upper and lower estimates, provides reasonable bounds on the load that could be removed by the practices examined. The upper estimated load reduction from combined street sweeping and structural controls, as a percentage of the total non-CSO load entering the lower Charles River downstream of Watertown Dam, was 44 percent for suspended solids, 34 percent for total lead, 14 percent for total phosphorus, and 17 percent for fecal coliform bacteria. The lower estimated load reduction from combined street sweeping and structural controls from non-CSO sources downstream of Watertown Dam, was 14 percent for suspended solids, 11 percent for total lead, 4.9 percent for total phosphorus, and 7.5 percent for fecal coliform bacteria. Load reductions by these combined management practices can be a small as 1.4 percent for total phosphorus to about 4 percent for the other constituents if the total load above Watertown Dam is added to the load from below the dam. Although the reductions in stormwater loads to the lower Charles River from the control practices examined appear to be minor, these practices would likely provide water-quality benefits to portions of the river during those times that they are most impaired-during and immediately after storms. It should also be recognized that only direct measurements of changes in stormwater loads before and after implementation of control practices can provide definitive evidence of the beneficial effects of these practices on water-quality conditions in the lower Charles River.

Massachusetts↗
USGS2003

Water resources of Monroe County, New York, water years 1997-99, with emphasis on water quality in the Irondequoit Creek basin—Atmospheric deposition, ground water, streamflow, trends in water quality, and chemical loads to Irondequoit Bay

Irondequoit Creek drains 169 square miles in the eastern part of Monroe County. Over time, nutrients transported by Irondequoit Creek to Irondequoit Bay on Lake Ontario have contributed to the eutrophication of the bay. Sewage-treatment-plant effluent, a major source of nutrients to the creek and its tributaries, was eliminated from the basin in 1979 by diversion to a regional wastewater-treatment facility, but sediment and contaminants from nonpoint sources continue to enter the creek and Irondequoit Bay. This report, the fourth in a series of reports that present interpretive analyses of the hydrologic data collected in Monroe County since 1984, interprets data from four surface-water monitoring sites in the Irondequoit Creek basin—Irondequoit Creek at Railroad Mills, East Branch Allen Creek at Pittsford, Allen Creek near Rochester, and Irondequoit Creek at Blossom Road. It also interprets data from three sites in the the Genesee River basin—Oatka Creek at Garbutt, Honeoye Creek at Honeoye Falls, and Black Creek at Churchville—as well as the Genesee River at Charlotte Pump Station, and also from a site on Northrup Creek at North Greece. The Northrup Creek site drains a 23.5-square-mile basin in western Monroe County, and provides information on surface-water quality in streams west of the Genesee River and on loads of nutrients delivered to Long Pond, a small eutrophic embayment of Lake Ontario. The report also includes water-level and water-quality data from nine observation wells in Ellison Park, and atmospheric-deposition data from a collection site at Mendon Ponds County Park. Average annual loads of some chemical constituents in atmospheric deposition for 1997–99 differed considerably from those for the long-term period 1984–96. Ammonia and potassium loads for 1997-99 were 144 and 118 percent greater, respectively, than for the previous period. Sodium and ammonia + organic nitrogen loads were 87 and 60 percent greater, respectively. Average annual loads of sulfate and orthophosphate for 1997-99 were 36 and 30 percent lower, respectively, than for the previous period. Loads of all nutrients deposited on the Irondequoit basin from atmospheric sources during 1997–99 greatly exceeded those transported by Irondequoit Creek. The ammonia load deposited on the basin was 139 times the load transported at Blossom Road (the most downstream site); the ammonia + organic nitrogen load was 6.3 times greater, orthophosphate 7.5 times greater, total phosphorus 1.3 times greater and nitrite + nitrate 1.5 times greater. Average yields of dissolved chloride and dissolved sulfate from atmospheric sources were much smaller than those transported by streamflow at Blossom Road.chloride was about 2 percent and sulfate about 8 percent of the amount transported. Trends in concentration of chemical constituents in surface water generally can be attributed to changes in land use, annual and seasonal variations in streamflow, and annual variations in the application of road salt to county highways and roads. Concentrations of several constituents in streams of the Irondequoit Creek basin showed statistically significant (α=0.05) trends from the beginning of their period of record through 1999. The constituent with the greatest number of significant trends was ammonia + organic nitrogen, with downward trends ranging from 4.1 to 5.6 percent per year at Allen Creek, Irondequoit Creek at Blossom Road, and East Branch Allen Creek. Orthophosphate showed an upward trend of 4.1 percent per year at Irondequoit Creek at Railroad Mills (the most upstream site). Dissolved chloride showed upward trends at Railroad Mills, Allen Creek, and Blossom Road. No trends in volatile suspended solids were noted at any of the four Irondequoit basin sites. Northrup Creek showed significant downward trends in concentrations of ammonia + organic nitrogen (3.3 percent per year), total phosphorus (3.4 percent per year), and orthophosphate (5.5 percent per year), and an upward trend for dissolved sulfate (1.8 percent per year). The Genesee River at Charlotte Pump Station showed downward trends of 6.1 percent per year for ammonia + organic nitrogen and 0.1 percent per year for chloride, and upward trends of 1.7 percent per year for total phosphorus and 6.6 percent per year for orthophosphate. Mean annual yields (mass per unit area) of most constituents at the Irondequoit Creek basin sites were similar to those noted for the previous report period (1994–96). East Branch Allen Creek showed lower yields of all constituents during 1997–99 than previously, even though runoff during 1997–99 was greater. These lower yields are attributed to the construction of an upstream detention basin on East Branch Allen Creek in 1995. Statistical analysis of long-term (greater than 12 years) streamflow records for unregulated streams in Monroe County indicated that annual mean flows for water years 1997–99 were in the normal range (75th to 25th percentile), although Allen Creek continues to show a significant downward trend in mean monthly streamflow during the 1984–99 water years.

New York↗
USGS2002

Bed-material entrainment potential, Roaring Fork River at Basalt, Colorado

The Roaring Fork River at Basalt, Colorado, has a frequently mobile streambed composed of gravel, cobbles, and boulders. Recent urban and highway development on the flood plain, earlier attempts to realign and confine the channel, and flow obstructions such as bridge openings and piers have altered the hydrology, hydraulics, sediment transport, and sediment deposition areas of the Roaring Fork. Entrainment and deposition of coarse sediment on the streambed and in large alluvial bars have reduced the flood-conveying capacity of the river. Previous engineering studies have identified flood-prone areas and hazards related to inundation and high streamflow velocity, but those studies have not evaluated the potential response of the channel to discharges that entrain the coarse streambed. This study builds upon the results of earlier flood studies and identifies some potential areas of concern associated with bed-material entrainment. Cross-section surveys and simulated water-surface elevations from a previously run HEC?RAS model were used to calculate the boundary shear stress on the mean streambed, in the thalweg, and on the tops of adjacent alluvial bars for four reference streamflows. Sediment-size characteristics were determined for surficial material on the streambed, on large alluvial bars, and on a streambank. The median particle size (d50) for the streambed samples was 165 millimeters and for the alluvial bars and bank samples was 107 millimeters. Shear stresses generated by the 10-, 50-, and 100-year floods, and by a more common flow that just inundated most of the alluvial bars in the study reach were calculated at 14 of the cross sections used in the Roaring Fork River HEC?RAS model. The Shields equation was used with a Shields parameter of 0.030 to estimate the critical shear stress for entrainment of the median sediment particle size on the mean streambed, in the thalweg, and on adjacent alluvial bar surfaces at the 14 cross sections. Sediment-entrainment potential for a specific geomorphic surface was expressed as the ratio of the flood-generated boundary shear stress to the critical shear stress (to/tc) with respect to two threshold conditions. The partial entrainment threshold (to/tc=1) is the condition where the mean boundary shear stress (to) equals the critical shear stress for the median particle size (tc) at that cross section. At this threshold discharge, the d50 particle size becomes entrained, but movement of d50-size particles may be limited to a few individual particles or in a small area of the streambed surface. The complete entrainment threshold (to/tc=2) is the condition where to is twice the critical shear stress for the median particle size, the condition where complete or widespread mobilization of the d50 particle-size fraction is anticipated. Entrainment potential for a specific reference streamflow varied greatly in the downstream direction. At some cross sections, the bed or bar material was mobile, whereas at other cross sections, the bed or bar material was immobile for the same discharge. The significance of downstream variability is that sediment entrained at one cross section may be transported into, but not through, a cross section farther downstream, a situation resulting in sediment deposition and possibly progressive aggradation and loss of channel conveyance. Little or no sediment in the d50-size range is likely to be entrained or transported through much of the study reach by the bar-inundating streamflow. However, the entrainment potential at this discharge increases abruptly to more than twice the critical value, then decreases abruptly, at a series of cross sections located downstream from the Emma and Midland Avenue Bridges. Median particle-size sediment is mobile at most cross sections in the study reach during the 10-year flood; however, the bed material is immobile at cross sections just upstream from the Upper Bypass and Midland Avenue Bridges. A similar s

Water-Resources Investigations Report↗
USGS2002

Spatial and temporal variations in streamflow, dissolved solids, nutrients, and suspended sediment in the Rio Grande Valley study unit, Colorado, New Mexico, and Texas, 1993–95

Streamflow and water quality vary spatially and temporally in the Rio Grande from Del Norte, Colorado, to El Paso, Texas. The variations in streamflow and in concentrations of selected waterquality constituents—dissolved solids, dissolved nitrite plus nitrate as nitrogen, total phosphorus, and suspended sediment—are described in this report. A multivariate linear regression model, ESTIMATOR2000, was used to estimate loads for selected constituents. Streamflow decreases in the downstream direction throughout most of the basin because outflows (due to agricultural use, leakage to ground water, and evapotranspiration) are greater than inflows. Streamflow increases between Rio Grande above the mouth of Trinchera Creek, near Lasauses, Colorado, to Rio Grande at Otowi Bridge, near San Ildefonso, New Mexico, because ground-water and tributary inflow are greater than outflow. Concentrations of dissolved solids, dissolved nitrite plus nitrate, total phosphorus, and suspended sediment generally increase in the downstream direction. Concentrations of dissolved solids, dissolved nitrite plus nitrate, and total phosphorus decrease between Rio Grande above the mouth of Trinchera Creek, near Lasauses, Colorado, and Rio Grande at Otowi Bridge, near San Ildefonso, New Mexico, because of dilution by tributary inflow. Concentrations of dissolved nitrite plus nitrate, total phosphorus, and suspended sediment decrease between Rio Grande Floodway at San Marcial, New Mexico, and Rio Grande below Leasburg Dam, near Leasburg, New Mexico, because of reservoir effects (nutrient uptake and settling of sediment). Several instances of decreasing streamflow and increasing loads indicate the presence of inflows with large constituent concentrations (relative to those of the Rio Grande immediately upstream from that inflow); this occurs (1) between Rio Grande near Del Norte, Colorado, and Rio Grande above the mouth of Trinchera Creek, near Lasauses, Colorado, for dissolved solids, (2) between Rio Grande at Otowi Bridge, near San Ildefonso, New Mexico, and Rio Grande Floodway at San Marcial, NewMexico, for all constituents, and (3) between Rio Grande below Leasburg Dam, near Leasburg, New Mexico, and Rio Grande at El Paso, Texas, for all constituents. Streamflow increases along every reach of the Rio Grande between the streamflow-gaging station Rio Grande above the mouth of Trinchera Creek, near Lasauses, Colorado, and the station Rio Grande at Otowi Bridge, near San Ildefonso, NewMexico. These increases in streamflow result in increases in the loads of dissolved solids, total phosphorus, and suspended sediment regardless of changes in concentrations.

Water-Resources Investigations Report↗
USGS2003

Nutrient, trace-element, and ecological history of Musky Bay, Lac Courte Oreilles, Wisconsin, as inferred from sediment cores

Sediment cores were collected from Musky Bay, Lac Courte Oreilles, and from surrounding areas in 1999 and 2001 to determine whether the water quality of Musky Bay has declined during the last 100 years or more as a result of human activity, specifically cottage development and cranberry farming. Selected cores were analyzed for sedimentation rates, nutrients, minor and trace elements, biogenic silica, diatom assemblages, and pollen over the past several decades. Two cranberry bogs constructed along Musky Bay in 1939 and the early 1950s were substantially expanded between 1950?62 and between 1980?98. Cottage development on Musky Bay has occurred at a steady rate since about 1930, although currently housing density on Musky Bay is one-third to one-half the housing density surrounding three other Lac Courte Oreilles bays. Sedimentation rates were reconstructed for a core from Musky Bay by use of three lead radioisotope models and the cesium-137 profile. The historical average mass and linear sedimentation rates for Musky Bay are 0.023 grams per square centimeter per year and 0.84 centimeters per year, respectively, for the period of about 1936?90. There is also limited evidence that sedimentation rates may have increased after the mid-1990s. Historical changes in input of organic carbon, nitrogen, phosphorus, and sulfur to Musky Bay could not be directly identified from concentration profiles of these elements because of the potential for postdepositional migration and recycling. Minor- and trace-element profiles from the Musky Bay core possibly reflect historical changes in the input of clastic material over time, as well as potential changes in atmospheric deposition inputs. The input of clastic material to the bay increased slightly after European settlement and possibly in the 1930s through 1950s. Concentrations of copper in the Musky Bay core increased steadily through the early to mid-1900s until about 1980 and appear to reflect inputs from atmospheric deposition. Aluminum- normalized concentrations of calcium, copper, nickel, and zinc increased in the Musky Bay core in the mid-1990s. However, concentrations of these elements in surficial sediment from Musky Bay were similar to concentrations in other Lac Courte Oreilles bays, nearby lakes, and soils and were below probable effects concentrations for aquatic life. Biogenic-silica, diatom-community, and pollen profiles indicate that Musky Bay has become more eutrophic since about 1940 with the onset of cottage development and cranberry farming. The water quality of the bay has especially degraded during the last 25 years with increased growth of aquatic plants and the onset of a floating algal mat during the last decade. Biogenic silica data indicate that diatom production has consistently increased since the 1930s. Diatom assemblage profiles indicate a shift from low-nutrient species to higher-nutrient species during the 1940s and that aquatic plants reached their present density and/or composition during the 1970s. The diatom Fragilaria capucina (indicative of algal mat) greatly increased during the mid-1990s. Pollen data indicate that milfoil, which often becomes more common with elevated nutrients, became more widespread after 1920. The pollen data also indicate that wild rice was present in the eastern end of Musky Bay during the late 1800s and the early 1900s but disappeared after about 1920, probably because of water-level changes more so than eutrophication.

Wisconsin↗