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At least 253 records · Page 14Linked to original sources
USGS2013

Seepage investigations of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2006-13

Seepage investigations were conducted annually by the U.S. Geological Survey from 1988 to 1998 and from 2004 to 2013 along a 64-mile reach of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, as part of the Mesilla Basin monitoring program. Results of studies conducted from 2006 to 2013 are presented in this report. Seepage investigations were conducted over a period of 1–2 days in February of each year, during low-flow conditions in the non-irrigation season. During the seepage investigations, discharge was measured at as many as 24 sites along the Rio Grande and as many as 20 inflow sites within the study reach. Net seepage gain or loss was computed for each subreach by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be significant when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. Study reaches during 2006 to 2013 ranged from 20.2 to 64 miles in length, and seepage losses ranged from 8.2 ± 3.1 to 47.9 ± 8.2 cubic feet per second.

New Mexico;Texas↗
USGS1980

Simulation of water-quality data at selected stream sites in the Missouri River Basin, Montana

Modification of sampling programs at some water-quality stations in the Missouri River basin in Montana has eliminated the means by which solute loads have been directly obtained in past years. To compensate for this loss, water-quality and streamflow data were statistically analyzed and solute loads were simulated using computer techniques. Functional relationships existing between specific conductance and solute concentration for monthly samples were used to develop linear regression models. The models were then used to simulate daily solute concentrations using daily specific conductance as the independent variable. Once simulated, the solute concentrations, in milligrams per liter, were transformed into daily solute loads, in tons, using mean daily streamflow records. Computer output was formatted into tables listing simulated mean monthly solute concentrations, in milligrams per liter, and the monthly and annual solute loads, in tons, for water years 1975-78.

Montana↗
USGS1983

Statistical analysis and evaluation of water-quality data for selected streams in the coal area of east-central Montana

To document and evaluate existing conditions of water quality prior to proposed coal development in east-central Montana, water-quality data were collected at 23 sites on selected streams from October 1975 through September 1981. The data were statistically summarized and regression equations were developed to define relationships between water-quality variables. Where applicable, measured water-quality conditions were compared to various water-use standards. Measured concentrations of dissolved solids ranged from 145 to 12,200 milligrams per liter. Concentrations commonly exceeded 1,000 milligrams per liter and thereby present a high to very high salinity hazard for irrigation. Streamflow of the area contains predominantly sodium and sulfate ions and generally constitutes a medium to very high sodium hazard for irrigation during base flow. The water in most streams is generally adequate for livestock consumption during base flow. Concentrations of suspended sediment were extremely variable and had a direct correlation to water discharge. Measured suspended-sediment concentrations ranged from 4 to 23 ,000 milligrams per liter. Sediment-transport curves were developed for 18 of the study sites. Mean annual suspended-sediment loads were determined at five sites using the flow-duration, sediment-transport curve method. Mean annual sediment loads ranged from 1,010 to 72,7000 tons. (USGS)

Water-Resources Investigations Report↗
USGS1916

Contributions to economic geology (short papers and preliminary reports), 1915: Part I. - metals and nonmetals except fuels

This volume is the thirteenth of a series that includes Bulletins 213, 225, 260, 285, 315, 340, 380, 430, 470, 530, 540, and 580, "Contributions to economic geology" for 1902, 1903, 1904, 1905, 1906 (Pt. I), 1907 (Pt. I), 1908 (Pt. I), 1909 (Pt. I), 1910 (P t. I), 1911 (Pt. I) , 1912 (Pt. I), and 1913 (Pt. I), respectively . These bulletins are prepared primarily to insure prompt publication of the economic results of investigations made by the United States Geological Survey. Beginning with the present volume the year included in the title will be the year of publication 1 instead of the year in which the field work reported was done. This volume is therefore dated 1915, and there will be no volume entitled "Contributions to economic geology, 1914." As the subtitle indicates, the papers included are of two classes -(1) short papers giving comparatively detailed description of occurrences that have economic interest but are not of sufficient importance to warrant a more extended description; (2) preliminary reports on economic investigations the results of which are to be published later in more detailed form. These papers are such only as have a direct economic bearing, all topic of purely scientific interest being excluded. Each paper has been issued as an advance chapter as soon as it was ready. Brief abstracts of the publications of the year are given in the annual report of the Director. The complete list of Survey publications affords, by means of finding list of subjects and of authors, further aid in ascertaining the extent of the Survey's work in economic geology. Since 1905 the annual economic bulletin has been printed in two parts, the second part comprising paper on mineral fuels. These volumes for 1906, 1907, 190 , 1909, 1910, 1911, 1912, and 1913 are Bulletins 316, 341, 381, 431, 471, 531, 541, and 581. Bulletin 621 forms Part II of the "Contributions" for 1915. The reports on work in Alaska have been printed in a separate series since 1904, the volume so far issued being Bulletins 259, 284, 314, 345, 379, 442, 480, 520, 542, 592, and 622.

Bulletin↗
USGS1984

Streamflow characteristics of the Yellowstone River basin, Montana, through September 1982

Statistical summaries of streamflow data for selected stream-gaging sites are presented in this report to aid in appraising streamflow in the Yellowstone River basin. Streamflow records are presented for 71 gaging stations for the period of record. Streamflow record collection in the Yellowstone River basin began in 1889. For each gaging station selected for this report, a brief description is given for station location, drainage area, period of record, revisions of previously published records, type and history of gages, regulation and diversions, average discharge, and extremes of discharge. This information is followed by tables of monthly and annual flow statistics, flood-frequency data, low-flow and high-flow frequency data, and flow-duration data. (USGS)

Water-Resources Investigations Report↗
USGS2010

Alluvial diamond resource potential and production capacity assessment of the Central African Republic

In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflict concerns. This meeting was supported later in 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberly Process Certification Scheme (KPCS) was ratified and signed by diamond-producing and diamond-importing countries. Over 70 countries were included as members of the KPCS at the end of 2007. To prevent trade in "conflict diamonds" while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging. The objective of this study was (1) to assess the naturally occurring endowment of diamonds in the Central African Republic (potential resources) based on geological evidence, previous studies, and recent field data and (2) to assess the diamond-production capacity and measure the intensity of mining activity. Several possible methods can be used to estimate the potential diamond resource. However, because there is generally a lack of sufficient and consistent data recording all diamond mining in the Central African Republic and because time to conduct fieldwork and accessibility to the diamond mining areas are limited, two different methodologies were used: the volume and grade approach and the content per kilometer approach. Estimates are that approximately 39,000,000 carats of alluvial diamonds remain in the eastern and western zones of the CAR combined. This amount is roughly twice the total amount of diamonds reportedly exported from the Central African Republic since 1931. Production capacity is calculated to be 840,000 carats per year, a number that is nearly twice the 450,000 carats per year reported annually by the Central African Republic. The difference in the two numbers reflects the lack of sufficient data on diamond resource grades, worker productivity, and the number and locations of sites being worked.

Scientific Investigations Report↗
USGS1995

Determination of base-flow characteristics at selected streamflow-gaging stations on the Mad River, Ohio

This report describes the results of a study to estimate characteristics of base flow and sustained ground-water discharge at five streamflow-gaging stations on the Mad River in Ohio. The five streamflow-gaging stations are located at Zanesfield, near Urbana, at St. Paris Pike (at Eagle City), near Springfield, and near Dayton. The median of the annual-mean base flows, determined by means of hydrograph separation, ranged from 0.64 (ft3/s)/mi2 (cubic feet per second per square mile) at Zanesfield to 0.74 (ft3/s)/mi2 at St. Paris Pike. The median percentage of annual total streamflow attributed to base flow ranged from 61.8 percent at Zanesfield to 76.1 percent near Urbana. Estimates of an upper limit (or threshold) at which base flows can be considered to be composed predominately of sustained ground-water discharge were made by constructing and analyzing base- flow-duration curves. The sustained ground-water discharges (base flows less than or equal to the estimated sustained ground-water-discharge thresholds) are assumed to originate from ground-water- flow systems that are minimally affected by seasonal climatic changes. The median sustained ground- water discharge ranged from 0.11 (ft3/s)/mi2 at Zanesfield to 0.26 (ft3/s)/mi2 at St. Paris Pike (at Eagle City) and near Springfield. The median sustained ground-water discharge, expressed as a percentage of the median annual-mean base flow, ranged from 17.2 percent at Zanesfield to 38.6 percent near Springfield.

Water-Resources Investigations Report↗
USGS2010

Water levels and selected water-quality conditions in the Mississippi River Valley alluvial aquifer in Eastern Arkansas, 2008

During the spring of 2008, the U.S. Geological Survey, in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey, measured 670 water levels in 659 wells completed in the Mississippi River Valley alluvial aquifer in eastern Arkansas. Groundwater levels are affected by groundwater withdrawals resulting in potentiometric-surface depressions. In 2008, the lowest water-level altitude was 69 feet above National Geodetic Vertical Datum of 1929 in the center of Arkansas County. The highest water-level altitude was 288 feet above National Geodetic Vertical Datum of 1929 in northeastern Clay County on the west side of Crowleys Ridge. Two large depressions in the potentiometric surface are located in Arkansas, Lonoke, and Prairie Counties and west of Crowleys Ridge in Craighead, Cross, Lee, Monroe, Poinsett, St. Francis, and Woodruff Counties. The elongated depression in Arkansas, Lonoke, and Prairie Counties has two areas that have changed in horizontal area or depth when compared to previous conditions of the aquifer. The area in Arkansas County in the southeastern half of the depression has not expanded horizontally from recent years, although the center of the depression has deepened. The area in Lonoke and Prairie Counties in the northwestern half of the depression has not expanded and water level in the deeper part of the depression has risen. In Lonoke and Prairie Counties in the northwestern half of the depression, the 90-foot contour shown on the 2006 potentiometric-surface map is not shown on the 2008 potentiometric-surface map. Along the west side of Crowleys Ridge, the area enclosed by 140-foot contour in Cross and Poinsett Counties has expanded further south into Cross County. The 130-foot contour in Poinsett County expanded north in 2008. The 130-foot contour is shown in Cross County, which was not evident in previous years. The 130-foot contour in St. Francis, Monroe, and Woodruff Counties in 2006 is not shown on the 2008 potentiometric-surface map. A map showing the difference in water level was constructed using 595 differences in water levels measured in 585 wells during 2008 and 2004. The difference in measured water levels from 2004 to 2008 ranged from -20.6 feet to 25.9 feet, with a mean of -1.6 feet. The largest decline of -20.6 feet occurred in Randolph County and the largest rise of 25.9 feet occurred in Prairie County. Out of the 595 differences, 442 were declines (74.3 percent), 10 were no difference (values of 0.0 ft) (1.7 percent), and 143 were rises (24.0 percent). Five areas are dominated by declines that are west of Crowleys Ridge; in eastern Craighead County; in southern Mississippi and Crittenden Counties; in eastern Lonoke and western Prairie Counties; and in Arkansas, Ashley, Chicot, Desha, Drew, and Lincoln Counties. Long-term water-level changes were evaluated using hydrographs from 173 wells in the Mississippi River Valley alluvial aquifer for the period 1984 to 2008. The mean annual rise or decline in water level for the entire study area was -0.38 feet per year (ft/yr) with a range of -4.86 to 0.58 ft/yr. Independence and White Counties are the only counties with a mean annual rise from 1984 to 2008. Mean annual declines between -0.50 ft/yr and 0.00 ft/yr occurred in Arkansas, Chicot, Clay, Craighead, Crittenden, Drew, Greene, Jefferson, Mississippi, Monroe, Phillips, Poinsett, Prairie, Pulaski, Randolph, and Woodruff Counties. Mean annual declines between -1.00 ft/yr and -0.50 ft/yr occurred in Ashley, Desha, Jackson, Lee, Lincoln, and St. Francis Counties. Mean annual declines between -1.50 ft/yr and -1.00 ft/yr occurred in Cross and Lonoke Counties. The analysis of long-term water-level changes in Arkansas, Lonoke, and Prairie Counties shows the elongation of the depression in these three counties. Arkansas and Prairie Counties have two different rates of annual decline for the two hydrographs shown for each county. Water levels in the two we

Scientific Investigations Report↗
USGS2020

Hydrologic and hydraulic analyses of selected streams in Stark County, Ohio

To update and expand a part of the Federal Emergency Management Agency Flood Insurance Study, the U.S. Geological Survey, the Muskingum Watershed Conservancy District, and the Stark County Commissioners began a cooperative study. The study consisted of hydrologic and hydraulic analyses for selected reaches of 14 streams in Stark County, Ohio: Broad-Monter Creek, Chatham Ditch, East Branch Nimishillen Creek, Fairhope Ditch, Firestone Ditch, Hayden Ditch, Middle Branch Nimishillen Creek, Middle Branch Nimishillen Creek Tributary Number 1, Nimishillen Creek, Reemsnyder Ditch, Sherrick Run, unnamed stream, West Branch Nimishillen Creek, and Zimber Ditch. The study totaled nearly 50 miles of stream reaches. Instantaneous peak streamflows for floods with 10-, 4-, 2-, 1-, and 0.2-percent and 1-percent plus annual exceedance probabilities were estimated using historical streamflow data from the streamgages Nimishillen Creek at North Industry, Ohio (U.S. Geological Survey station number 03118500), and Middle Branch Nimishillen Creek at Canton, Ohio (U.S. Geological Survey station number 03118000), regional flood regression equations, and streamflow urbanization techniques. The annual exceedance probability streamflows were then used in a Hydrologic Engineering Center-River Analysis System step-backwater model to determine water-surface profiles, flood-inundation boundaries for the 10-, 4-, 2-, 1-, and 0.2-percent and 1-percent plus annual exceedance probability floods, and a regulatory floodway along a selected reach of each stream. Model input included DEM-derived cross sections supplemented with field surveys of open channel cross sections and hydraulic structures, field estimates of roughness values, and annual exceedance probability flood estimates from regional regression equations and historical streamflow data. Flood-inundation boundaries were mapped for the 1- and 0.2-percent annual exceedance probability floods and a regulatory floodway for each stream reach.

Ohio↗
USGS2021

Hydrologic and hydraulic analyses of the Grand River, Red Cedar River, and Sycamore Creek near Lansing, Michigan

The U.S. Geological Survey (USGS) completed hydrologic and hydraulic analyses for selected reaches of the Grand River, Red Cedar River, and Sycamore Creek near Lansing, Michigan, in cooperation with the city of Lansing. The study comprised a 3.1-mile reach of the Grand River, a 30.3-mile reach of the Red Cedar River, and a 12.0-mile reach of Sycamore Creek. The information produced from the study can be used to update and expand an existing Federal Emergency Management Agency Flood Insurance Study for Ingham County, Mich. Historical streamflow data from USGS streamgages on Grand River at Lansing, Mich. (station number 04113000); Red Cedar River at East Lansing, Mich. (station number 04112500); Red Cedar River near Williamston, Mich. (station number 04111379); and Sycamore Creek at Holt Road near Holt, Mich. (station number 04112850) were used to estimate instantaneous peak streamflows for floods with 10-, 4-, 2-, 1-, and 0.2-percent annual exceedance probabilities (AEPs) and a “1-percent plus” AEP. The Hydrologic Engineering Center’s River Analysis System step-backwater model was used to determine water-surface elevation profiles for the 10-, 4-, 2-, 1-, and 0.2-percent AEP floods, the 1-percent plus AEP flood, and a regulatory floodway for each stream reach. The hydraulic models were calibrated based on stage-streamflow ratings at USGS streamgages. Flood-inundation boundaries for the 1- and 0.2-percent annual exceedance probability floods and regulatory floodway were created for each stream.

Michigan↗
USGS2001

Nutrient and suspended-sediment concentrations and loads and benthic-invertebrate data for tributaries to the St. Croix River, Wisconsin and Minnesota, 1997-99

Nutrient and suspended-sediment data were collected on major tributaries to the St. Croix River during 1997-99 as part of three studies. The first study, done in 1997 as part of the U.S. Geological Survey?s National Water-Quality Assessment Program Upper Mississippi Study Unit, was a widespread synoptic survey of nutrient and suspended-sediment concentrations, loads, and yields during snowmelt. Runoff from snowmelt in agricultural areas and other areas with low permeability soils had significantly greater nutrient concentrations than forested areas, whereas differences in suspended-sediment loading were not detected. In 1998, synoptic samplings of 11 tributaries were done during snowmelt, base-flow, and storm-runoff periods. These studies showed that the Apple, Willow, and Kinnickinnic Rivers were major contributors of suspended sediments and nutrients to the St. Croix River during base flow and storm-runoff events. Nitrate concentrations were high during base flow in the agricultural tributaries?specifically, the Kinnickinnic (4.83 mg/L), Willow (1.53 mg/L), and Apple (0.79 mg/L) Rivers?possibly from ground-water recharge or point-source contributions. Extensive water-quality sampling was done monthly and during high-flow events in water year 1999 (October 1, 1998 to September 30, 1999) in coordination with continuous streamflow monitoring at 12 sites in the St. Croix River Basin. These data were used to compute annual nutrient and suspended-sediment loads and yields at the monitored sites for water year 1999. Relations among environmental characteristics and calculated annual nutrient and suspended-sediment yields were used to estimate loading from unmonitored parts of the basin. The environmental characteristics found to best estimate annual yields were soil characteristics (clay, permeability of soil, and erodibility), basin slope and area, and the percentages of wetland and urban areas in the basins. Variability in 1999 rainfall intensity resulted in annual yields from several northern, forested basins being higher than those from the southern, agricultural basins. The Sunrise River had the highest annual suspended-sediment and nutrient yields in the basin in 1999. Concentrations and instantaneous loading rates varied as much among various flow conditions at individual sites as among sites during the three years of study. Benthic invertebrates were sampled and indices of water quality were calculated at 16 tributaries in fall 1999. Benthic invertebrate indices indicated excellent to good water quality at all tributaries except Valley Creek, Willow River, and Kettle River. No relations were found between benthic invertebrate indices and the calculated and estimated 1999 annual tributary loads and yields.

Minnesota, Wisconsin↗
USGS2003

Relations between precipitation and daily and monthly mean flows in gaged, unmined and valley-filled watersheds, Ballard Fork, West Virginia, 1999-2001

Large-scale surface mining using valley fills has changed hydrologic storage and processes in the Ballard Fork Watershed in West Virginia. Total unit flow for the 2-year study period (November 15, 1999?November 14, 2001) on the Unnamed Tributary (extensively mined) (11,700 cubic feet per second per square mile) was almost twice that on Spring Branch (unmined) (6,260 cubic feet per second per square mile), and about 1.75 times that on Ballard Fork (downstream, partly mined) (6,690 cubic feet per second per square mile). Unit flow from the Unnamed Tributary exceeded that from the other two streams for all flows analyzed (5?95 percent duration). Unit flow from Ballard Fork exceeded unit flow from Spring Branch about 80 percent of the time, but was about the same for high flows (less than 20 percent duration). The proportional differences among sites were greatest at low flows. Spring Branch was dry for several days in October and November 2000 and for most of October 2001, and the Unnamed Tributary had flow throughout the study period. The increase in flows from mined parts of the Ballard Fork Watershed appears to result from decreases in evapotranspiration caused by removal of trees and soil during mining. During both years, evapotranspiration from the Spring Branch Watershed greatly exceeded that from the Unnamed Tributary Watershed during May through October, when leaves were open. Evapotranspiration from the Unnamed Tributary Watershed slightly exceeded that from the Spring Branch Watershed in February and March during both years. Evapotranspiration, as a percentage of total rainfall, decreased from the first to the second, drier, year from the Unnamed Tributary Watershed (from 61 percent to 49 percent) but changed little from the Spring Branch (from 77 to 76 percent) and Ballard Fork (73 to 76 percent) Watersheds. Precipitation and flow during the study period at three nearby long-term sites, the U.S. Geological Survey stream-gaging station East Fork Twelvepole Creek near Dunlow, West Virginia, and two National Oceanic Atmospheric Administration rain gages at Madison and Dunlow, West Virginia, were less than long-term annual averages. Relations observed among the three streams in the Ballard Fork Watershed during this study may not represent those in years when annual precipitation and flow are closer to long-term averages.

West Virginia↗
USGS1979

Water resources of the Lower Elwha Indian Reservation, Washington

The Lower Elwha Indian Reservation covers 372 acres at the mouth of the Elwha River in Clallam County, Washington. The land of the reservation is used principally for residential purposes and growing forage for cattle. The population of the reservation is largely dependent upon fisheries resources for its economic health. This study was made to assess the availability and suitability of ground water on the reservation for domestic use and for fish propagation, to determine the streamflow characteristics of the Elwha River and Bosco Creek, and to determine the chemical and physical quality of the area's surface and ground waters. Existing wells on the reservation range in depth from about 30 to about 80 feet, and produce water of excellent chemical quality. Properly constructed wells in favorable locations on the reservation should be capable of large yields, up to 5,000 gallons per minute. Intrusion of seawater into the aquifers of the reservation has not occurred. However, if massive quantities of ground water are withdrawn, intrusion could occur. The Elwha River, which flows along the western margin of the reservation has a mean annual flow of about 1,500 cubic feet per second (ft 3 /s). The recorded minimum daily discharge was 10 ft 3 /s, and the maximum was 41,600 ft 3 /s. The river floods the lower parts of the reservation annually, and extensive flooding is common. Water in the Elwha River is of excellent chemical quality, and its recorded temperature has ranged from 36° to 64°F. Bosco Creek, the only other stream on or adjacent to the reservation, has an estimated mean annual flow of 1.1 ft 3 /s.

Washington↗
USGS1987

Floods in Kansas and techniques for estimating their magnitude and frequency on unregulated streams

Techniques are presented for generalizing the skewness coefficient of log-Pearson Type III distributions of annual maximum discharges and for flood magnitudes that have selected recurrence intervals from 2 to 100 yr. A weighted least-square (WLS) regression model was used to generalize the coefficients of station skewness that resulted in a root-mean-sq error of prediction of 0.35 compared to 0.55 for the skewness map published in Bulletin 17B of the U.S. Water Resources Council. Estimates of generalized skewness were computed for each of 245 streamflow gaging stations with a minimum of 10 years of record and a contributing drainage area of < 20,000 sq mi. The WLS regression model also was used to develop equations for estimating flood magnitude for selected recurrence intervals for ungaged stream locations by using data from 218 of the 245 streamflow gaging stations that had contributing-drainage areas of less than 10,000 sq mi. The errors of prediction of the most reliable WLS equations ranged from 28 to 42%. The WLS equations were compared statistically to previous developed equations and were determined to be different and more accurate than previously published equations. Flood magnitudes and frequencies for 245 streamflow gaging stations, based on data collected through the 1983 water year, are presented along with a summary of the seasonal distribution of annual maximum discharges and an analysis of the maximum observed discharges. (Author 's abstract)

Water-Resources Investigations Report↗
USGS1986

Sediment-data sources and estimated annual suspended-sediment loads of rivers and streams in Colorado

Sources of sediment data collected by several government agencies through water year 1984 are summarized for Colorado. The U.S. Geological Survey has collected suspended-sediment data at 243 sites; these data are stored in the U.S. Geological Survey 's water data storage and retrieval system. The U.S. Forest Service has collected suspended-sediment and bedload data at an additional 225 sites, and most of these data are stored in the U.S. Environmental Protection Agency 's water-quality-control information system. Additional unpublished sediment data are in the possession of the collecting entities. Annual suspended-sediment loads were computed for 133 U.S. Geological Survey sediment-data-collection sites using the daily mean water-discharge/sediment-transport-curve method. Sediment-transport curves were derived for each site by one of three techniques: (1) Least-squares linear regression of all pairs of suspended-sediment and corresponding water-discharge data, (2) least-squares linear regression of data sets subdivided on the basis of hydrograph season; and (3) graphical fit to a logarithm-logarithm plot of data. The curve-fitting technique used for each site depended on site-specific characteristics. Sediment-data sources and estimates of annual loads of suspended, bed, and total sediment from several other reports also are summarized. (USGS)

Colorado↗
USGS1997

Water quality variability in San Francisco Bay, Some gGeneral lessons from 1996 sampling: 1996 annual report, San Francisco estuary regional monitoring program for trace substances

This report describes the results from the 1996 Regional Monitoring Program for Trace Substances (RMP). It is the fourth Annual Report from the RMP which began in 1993 and attempts to synthesize the most obvious data patterns from the last four years. This report includes data from Base Program monitoring activities, as well as results of Pilot and Special Studies conducted or completed in 1996. Additionally, several articles contributed by RMP investigators and others, are included. These articles provide perspective and insight on important contaminant issues identified by the RMP. This summary addresses which kinds of pollutants measured by the RMP appear to be at levels that warrant concern, what kinds of trends may be discerned, and which stations have consistently shown elevated contaminant levels. The goals or general objectives of the RMP are: 1. To obtain high quality baseline data describing the concentrations of toxic and potentially toxic trace elements and organic contaminants in the water and sediment of the San Francisco Estuary. 2. To determine seasonal and annual trends in chemical and biological water quality in the San Francisco Estuary. 3. To continue to develop a data set that can be used to determine long-term trends in the concentrations of toxic and potentially toxic trace elements and organic contaminants in the water and sediments of the San Francisco Estuary. 4. To determine whether water quality and sediment quality in the Estuary at large are in compliance with objectives established by the Basin Plan (the regulatory planning document used by the Regional Water Quality Control Board). 5. To provide a database on water and sediment quality in the Estuary which is compatible with data being developed in other ongoing studies, including wasteload allocation studies and model development, sediment quality objectives development, in-bay studies of dredged material disposal, Interagency Ecological Program (IEP) water quality studies, primary productivity studies, local effects biomonitoring programs, and state and federal mussel watch programs.

California↗