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USGS1998

Water resources of Mellette and Todd counties, South Dakota

Mellette and Todd Counties are located in south-central South Dakota and have a combined area of 2,694 square miles. The White River and its tributaries, which include the Little White River, drain Mellette County and about one-half of Todd County. Tributaries to the Niobrara River, which include the Keya Paha River, drain the other one-half of Todd County. The average discharge of the Little White River is about 56 cubic feet per second as the river enters Todd County and is about 131 cubic feet per second as it discharges to the White River in northern Mellette County. The average discharge of the Keya Paha River just outside Todd County is about 39 cubic feet per second. The average annual runoff for Mellette and Todd Counties ranges from 0.94 to 2.36 inches based on records from nine streamflow-gaging stations in and near the counties. The average annual runoff is 1.62 inches, which compares with the average annual precipitation of about 19 inches. In Todd County, shallow wells completed in the alluvial, Ogallala, Arikaree, and White River aquifers generally can supply water that has low concentrations of dissolved solids, is fresh, and is soft to moderately hard. Ground water from shallow aquifers is limited in Mellette County; therefore, deep wells, often greater than 1,000 feet, are sometimes installed. The Pierre Shale often is used to supply rural domestic and stock wells in Mellette County even though well yields are low and the water has high dissolved solids, is moderately saline, and is very hard. Alluvial aquifers are present in both counties and store an estimated 1.6 million acre-feet of water. The water quality of the alluvial aquifers is dependent on the underlying deposits, and generally the water has low concentrations of dissolved solids, is fresh, and is soft to moderately hard where underlain by the Ogallala and Arikaree Formations; has moderate concentrations of dissolved solids, is slightly saline, and is hard where underlain by the White River Group; and has high concentrations of dissolved solids, is saline, and is very hard where underlain by the Pierre Shale. Also, yields often are lower where the alluvial aquifers are underlain by the Pierre Shale. The Ogallala aquifer is present in only Todd County, and the Arikaree aquifer is present throughout most of Todd County and southwestern and south-central Mellette County. The Ogallala aquifer contains an estimated 17 million acre-feet of water in storage, and the Arikaree aquifer contains an estimated 50 million acre-feet of water in storage. Both aquifers generally are suitable for irrigation, and yields from these aquifers are sometimes greater than 1,000 gallons per minute. Nitrate concentrations in 13 out of 92 water samples collected from the Ogallala aquifer exceeded the Primary Drinking Water Maximum Contaminant Level (MCL) of 10 milligrams per liter. In 11 out of 46 samples collected from the Arikaree aquifer, arsenic concentrations exceeded the MCL of 50 micrograms per liter. The White River aquifer, where present, is usually the shallowest source of ground water in Mellette County. The White River aquifer also is used in northern Todd County where the Ogallala and Arikaree aquifers are not present. The White River aquifer contains an estimated 50 million acre-feet of water in storage. Reported yields from the aquifer range from 1 to 30 gallons per minute, which generally is insufficient to support irrigation in most areas. However, yields are sufficient for livestock-watering and rural-domestic purposes. In both counties, the Pierre Shale is the shallowest bedrock aquifer and is exposed at the land surface throughout most of Mellette County. This aquifer is used primarily in Mellette County. Although the aquifer contains an estimated maximum of 1.5 million acre-feet of water in storage, it is not a viable source of ground water because the aquifer is relatively impermeable, yields are low, and water usually can be obtained from shallower sources, especially in Todd County. Reported yields from the Pierre Shale aquifer range from 1 to 8 gallons per minute. Because few test holes and wells penetrate below the Pierre Shale, little is known about the extent of the deeper bedrock aquifers. All wells completed in the Dakota Sandstone, Inyan Kara, and Minnelusa and Madison aquifers in the counties are used for stock-watering purposes. High concentrations of dissolved solids and hard water are characteristic of the water quality in the bedrock aquifers. Depths to the top of the deeper bedrock aquifers range from 1,270 feet to greater than 2,000 feet below land surface.

South Dakota↗

USGS2011

Recent (2008-10) concentrations and isotopic compositions of nitrate and concentrations of wastewater compounds in the Barton Springs zone, south-central Texas, and their potential relation to urban development in the contributing zone

During 2008–10, the U.S. Geological Survey, in cooperation with the City of Austin, the City of Dripping Springs, the Barton Springs/Edwards Aquifer Conservation District, the Lower Colorado River Authority, Hays County, and Travis County, collected and analyzed water samples from five streams (Barton, Williamson, Slaughter, Bear, and Onion Creeks), two groundwater wells (Marbridge well [YD–58–50–704] and Buda well [LR–58–58–403]), and the main orifice of Barton Springs in Austin, Texas, with the objective of characterizing concentrations and isotopic compositions of nitrate and concentrations of wastewater compounds in the Barton Springs zone. The Barton Springs zone is in south-central Texas, an area undergoing rapid growth in population and in land area affected by development, with associated increases in wastewater generation. Over a period of 17 months, during which the hydrologic conditions transitioned from dry to wet, samples were collected routinely from the streams, wells, and spring and, in response to storms, from the streams and spring; some or all samples were analyzed for nitrate, nitrogen and oxygen isotopes of nitrate, and wastewater compounds. The median nitrate concentrations in routine samples from all sites were higher in samples collected during the wet period than in samples collected during the dry period, with the greatest difference for stream samples (0.05 milligram per liter during the dry period to 0.96 milligram per liter for the wet period). Nitrate concentrations in recent (2008–10) samples were elevated relative to concentrations in historical (1990–2008) samples from streams and from Barton Springs under medium- and high-flow conditions. Recent nitrate concentrations were higher than historical concentrations at the Marbridge well but the reverse was true at the Buda well. The elevated concentrations likely are related to the cessation of dry conditions coupled with increased nitrogen loading in the contributing watersheds. An isotopic composition of nitrate (delta nitrogen–15) greater than 8 per mil in many of the samples indicated there was a contribution of nitrate with a biogenic (human and or animal waste, or both) origin. Wastewater compounds measured in routine samples were detected infrequently (3 percent of cases), and concentrations were very low (less than the method reporting level in most cases). There was no correlation between nitrate concentrations and the frequency of detection of wastewater compounds, indicating that wastewater compounds might be undergoing removal during such processes as infiltration through soil. Three potential sources of biogenic nitrate to the contributing zone were considered: septic systems, land application of treated wastewater, and domesticated dogs and cats. During 2001–10, the estimated densities of septic systems and domesticated dogs and cats (number per acre) increased in the watersheds of all five creeks, and the rate of land application of treated wastewater (gallons per day per acre) increased in the watersheds of Barton, Bear, and Onion Creeks. Considering the timing and location of the increases in the three sources, septic systems were considered a likely source of increased nitrate to Bear Creek; land application of treated wastewater a likely source to Barton, Bear, and Onion Creeks; and domestic dogs and cats a potential source principally to Williamson Creek. The results of this investigation indicate that baseline water quality, in terms of nitrate, has shifted upward between 2001 and 2010, even without any direct discharges of treated wastewater to the creeks.

Texas↗

USGS2004

Characterization and simulation of flow in the lower Arkansas River alluvial aquifer, south-central Kansas

Large parts of the lower Arkansas, Ninnescah, and Walnut River Basins in south-central Kansasan area that includes Wichita, the largest city in Kansasare experiencing rapid population growth and, consequently, increasing demands on surface- and ground-water resources in addition to agricultural irrigation in the area. The quantity and quality of water available in the lower Arkansas, Ninnescah, and Walnut River Basins in Butler, Cowley, Sedgwick, and Sumner Counties are crucial as population and water use continue to increase in the region. A steady-state model was constructed to simulate flow in the Arkansas River alluvial aquifer between Wichita and Arkansas City. Calibration was achieved using March 2001 measured water levels and streamflow gain using long-term (19402001) streamflow records. Average recharge about 5 inches per year; average aquifer hydraulic conductivity was about 500 feet per day; well pumpage (average of reported 19982001 use) was 56 cubic feet per second; and net flow from the alluvial aquifer to streams in the modeled area was computed by hydrograph separation to be 157 cubic feet per second. Nine hypothetical simulations were conducted with ground-water pumpage varying from zero to double authorized pumpage (206 cubic feet per second). Net remaining aquifer thickness declined for the largest simulated pumpage increases in comparison to 19982001 average pumping, as did flow from the aquifer to the Arkansas River. Simulated aquifer thickness decreases were more pronounced in areas where pumpage is currently (2004) greatest.

Scientific Investigations Report↗

USGS2014

2009 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, and reports of unusual activity at or near eight separate volcanic centers in Alaska during 2009. The year was highlighted by the eruption of Redoubt Volcano, one of three active volcanoes on the western side of Cook Inlet and near south-central Alaska's population and commerce centers, which comprise about 62 percent of the State's population of 710,213 (2010 census). AVO staff also participated in hazard communication and monitoring of multiple eruptions at ten volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

Alaska↗

USGS2021

Groundwater assessment for petroleum hydrocarbon compounds associated with Fuels Area C, Ellsworth Air Force Base, South Dakota, 2014–18

In 2013, the U.S. Geological Survey began a study in cooperation with the Defense Logistics Agency and the U.S. Air Force to estimate groundwater-flow direction, install groundwater monitoring wells, and collect soil and groundwater samples for petroleum hydrocarbon compounds to identify the presence of hydrocarbon contamination at Ellsworth Air Force Base, South Dakota, specifically around Fuels Area C. Several fuel spills of diesel fuel, jet fuel, and other petroleum products were documented on or near Fuels Area C and several studies have been done to determine the extent of petroleum hydrocarbon contamination in the subsurface. Two-dimensional electrical resistivity tomography surveys were completed at Fuels Area C in 2014 to characterize subsurface materials and determine the depth to bedrock along survey lines. The depth to the top of the Pierre Shale from land surface along the four electrical resistivity tomography survey lines in Fuels area C ranged from about 5.4 to 8.7 meters. Resistivity lines and lithologic logs in wells in the area indicated mostly clay material with minor occurrences of sand and gravel. Discrete groundwater levels were collected between November 2014 and June 2018 at 14 monitoring wells for use in generating a potentiometric surface in the study area around Fuels Area C. The potentiometric contours indicated that groundwater flow was from the west to east or southwest to southeast around Fuels Area C. Soil and groundwater samples were collected at selected locations from 2014 to 2018 to better understand the presence and movement of petroleum hydrocarbons in the study area around Fuels Area C. Soil samples were collected at eight wells during installation in 2014 and three wells during installation in 2016. Groundwater samples were collected from 14 wells and a recovery sump around Fuels Area C from 2014 to 2018. Several petroleum hydrocarbon compounds were detected, but below action levels, in soil samples collected in 2014 and 2016. Benzene and toluene were not detected in any of the soil samples from the 11 monitoring well sites. Ethylbenzene and total xylenes were detected at sites 1 and 7. Naphthalene was detected in samples from five sites (sites 1, 5, 7, 8, and 9), but concentrations were less than the Tier 1 action level of 25 milligrams per kilogram. Gasoline-range organic compounds were detected in all soil samples collected during the installation of 11 groundwater monitoring wells within or near Fuels Area C in 2014 and 2016. Diesel-range organic compounds were detected in 9 out of the 11 soil samples collected at the 11 monitoring wells. Gasoline-range organic compound concentrations exceeded the Tier 2 assessment level for total petroleum hydrocarbons in soil samples from site 1 (5,200 milligrams per kilogram), site 5 (580 milligrams per kilogram), and site 9 (1,800 milligrams per kilogram); the remaining sites had concentrations below the Tier 2 assessment level for total petroleum hydrocarbons. The highest concentrations of diesel-range organic compounds in soil samples were from site 1 (3,600 milligrams per kilogram), site 5 (440 milligrams per kilogram), and site 14 (330 milligrams per kilogram), and only the sample from site 1 exceeded the Tier 2 assessment level for total petroleum hydrocarbons. Petroleum hydrocarbon concentrations were measured in samples collected from 14 groundwater monitoring wells and 1 recovery sump between 2014 and 2018 in the study area around Fuels Area C. Benzene, toluene, ethylbenzene, and xylene (BTEX) compounds were detected in at least one sample collected from 10 of the 15 sites sampled in the study area from 2014 to 2018. Samples from monitoring well sites 2, 3, 6, 8, and 9 did not have any quantifiable concentrations of BTEX compounds. Multiple BTEX compounds were detected consistently in samples collected from sites 10 and 11. Few BTEX compounds were detected at sites outside of and downgradient from Fuels Area C (sites 12–14). Naphthalene was detected in 8 of the 15 sites sampled in the study area in 2014–18. Measurable concentrations of naphthalene generally were less than 5 micrograms per liter in wells sampled in the study area in 2014–18 except for samples collected at sites 5, 7, and 11. The variability of the presence of BTEX compounds and naphthalene in wells sampled in the study area during 2014–18 likely is caused by the variability in the subsurface material, local groundwater flow, operational fueling activities, and historical spills and releases in the area. The spatial and temporal variability in the BTEX compounds and naphthalene concentrations from samples collected from 2014 to 2018 do not indicate a consistent pattern of subsurface flow or contaminate movement that would be expected if a contaminant plume migrated with the flow and movement of groundwater. Gasoline-range organic and diesel-range organic compounds were detected in most of the groundwater samples collected in the study area around Fuels Area C in 2014–18; however, concentrations were often less than the laboratory reporting level. Median gasoline-range organic compound concentrations were greater than the laboratory reporting level at sites 1, 5, 9, 10, and 11. The highest concentrations of gasoline-range organic and diesel-range organic compounds generally were observed in samples collected from sites 10 and 11. Gasoline-range organic compound concentrations ranged from 1,500 to 9,700 micrograms per liter at site 10 and from less than 100 to 13,000 micrograms per liter at site 11. Diesel-range organic compound concentrations ranged from 9,600 to 55,000 micrograms per liter at site 10 and from 560 to 7,300 micrograms per liter at site 11.

South Dakota↗

USGS2025

Shallow geologic framework of the Mississippi Sound and the potential for sediment resources

The Mississippi Sound, an estuarine environment located between the mainland and barrier islands bordering the northern Gulf of America (formerly the Gulf of Mexico), serves as a vital ecosystem for the States of Mississippi and Alabama. Spanning approximately 100 kilometers from east to west and covering 1,400 square kilometers, the sound is home to marine industry and ports, and its shallow and brackish waters sustain a diverse array of marine life. Barrier islands along the southern edge of the sound separate the microtidal estuary from the Gulf of America. This protection from gulf wave action mediates current flow within the sound, resulting in predominantly fine-grained sediment deposition along the seafloor. This study, conducted by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers, provides insight on fluvial and tidal processes spanning the past 5,000 years. The report synthesizes existing research to provide a comprehensive overview of the sound geology, from Pleistocene origins to present-day morphology, and utilizes high-resolution single channel seismic profiles and sediment data to identify and map sedimentary deposits and morphologic features at and below the seafloor. Despite its ecological significance, the Mississippi Sound faces environmental challenges, including water-quality issues, habitat degradation, storm-induced erosion, and the ongoing threats of sea-level rise and environmental changes. This study uses the present-day understanding of the sound's geology to inform coastal management decisions, hazard assessment, and potential mineral resources.

Louisiana, Mississippi↗

USGS1984

Estimate of self-supplied domestic water use in Oklahoma during 1980

Reported or measured water-use data for the domestic self-supplied user were not available for Oklahoma; therefore estimates of water use within this classification were derived. The total self-supplied population in Oklahoma during 1980 was estimated to be 343,615, which was 11.4 percent of the total 1980 State population. The rate of water use by this group was estimated to be 56 gallons per capita per day. The estimated annual domestic self-supplied water use by county ranged from 10 to 1,180 acre-feet, with a total statewide use of 21,610 acre-feet.

Water-Resources Investigations Report↗

USGS1985

Water resources of the southeast lowlands, Missouri; with a section on water quality

The Southeast Lowlands of Missouri occupies 4,000 square miles of prime agricultural land of the Coastal Plain in the extreme southeastern corner of Missouri. Even though this area receives about 4 feet of rainfall per year, there is a rapidly increasing demand for water for irrigation. The purpose of this study was to evaluate the water resources of this area with particular emphasis on the extent of irrigation and the potential of the groundwater system to support further irrigation development. The area is underlain by consolidated aquifers of Paleozoic age and unconsolidated aquifers of Mesozoic and Cenozoic age. The consolidated aquifers, although possessing the potential to yield large quantities of water, generally are not used throughout much of the area because they lie at considerable death and alternate supplies are readily available. The McNairy aquifer, which underlies about three-fourths of the area, ranges from 0 to 600 feet in thickness with the top lying from 0 to more than 2,200 feet below land surface. This system is attractive as a municipal water supply because of its large artesian head and the small iron and hardness concentrations of the water. Although this system is now used exclusively for municipal water supplies, the McNairy may become more important in the future as a heat source. The Wilcox Group (undivided), which underlies more than one-half of the area and almost always lies less than 300 feet below land surface, is as much as 1,400 feet thick. However, usually only the basal 250 to 500 feet of this group is used as an aquifer. This system, which in some areas is capable of yielding as much as 1,500 gallons per minute to properly constructed wells, is now primarily used for municipal supplies. The alluvial aquifer underlies most of the area and is locally capable of yielding more than 3,000 gallons per minute. This aquifer generally is 100 to 200 feet thick, but in several places more than 250 feet of alluvium has been reported. Irrigation wells withdraw an estimated 95,000 acre-feet per year from this aquifer, whereas municipal, industrial, and domestic wells withdraw an estimated additional 17,000 acre-feet per year. This compares to nearly 6 million acre-feet per year natural discharge and a total storage of 60 million acre feet. The surface-water system in the area consists of a few natural rivers and many manmade ditches. Although a considerable quantity of water is available from the surface-water system, this system is not extensively used because attractive alternative sources are readily available.

Missouri↗

USGS1986

Measurement of scour-depth near bridge piers

River-bed scour is a major source of damage to bridge piers and bridge abutments. When scour depth exceeds design limits, the supporting material around the footings is washed away and the structure becomes unstable. Equations for predicting scour-depth show a significant lack of agreement so portable equipment for measuring scour is needed. This report discusses the design of an instrumented, unmanned boat that (a) can be launched and controlled from a bridge and (b) can be maneuvered in flood flows that reach velocities of 15 feet per second. Calculations indicate the battery-powered propulsive system alone will weigh about 300 pounds and that the craft must be about 15-feet long. Because a free-running craft will be undesirably heavy and large, other methods of obtaining scour data are proposed. A tethered craft fitted with a controllable rudder and some methods of measuring scour at a point are presented for future study and development.

Water-Resources Investigations Report↗

USGS1987

Ground-water levels in the alluvial aquifer at Louisville, Kentucky, 1982-87

Water level data have been collected in the alluvial aquifer at Louisville, Kentucky by the U.S. Geological Survey since 1943. Interpretations of these data have been published in several reports by the Survey, but none have been published since 1983. Contour maps and hydrographs are presented in this report to document and to help interpret water level changes for the period 1982-87. Maps and hydrographs show that groundwater levels generally stabilized in the 1980 's after rising for many years. Two areas of groundwater withdrawals are apparent in the maps and hydrographs. Withdrawals in an industrial area in west Louisville disrupt the typical pattern of the contours to curve landward around the area of withdrawal. Resumption of pumping of groundwater for heating and cooling of some buildings in the downtown area in 1985 caused declines of about 3 to 4 ft in the downtown area. (Author 's abstract)

Water-Resources Investigations Report↗

USGS1991

Water withdrawals in the Black Warrior-Tombigbee Basin and Alcorn County, Mississippi, 1985-87

Public-supply and industrial water withdrawals were inventoried for the Mississippi part of the Black Warrior-Tombigbee Basin and for Alcorn County, Mississippi. The study area, located in the northeastern part of the State, is largely forested or agricultural land, with some industries near the larger towns. A water-resource capacity analysis was done to determine a risk rating for each inventoried facility, evaluating the likelihood of the facility exceeding the capacity of its current source of water at the existing level of use. Published reports and potentiometric maps were used in this analysis to determine the source capacity and the effects withdrawals have had on each water source. The public-supply and industrial water withdrawals in the basin are from ground water, with the exception of the city of Columbus. About 97 percent of the total withdrawal of 80 million gallons per day is from ground water. Water-supply systems in three areas were determined to have a high risk of exceeding the water-resource capacity: the Tupelo-Lee County area, the West Point (Clay County) area, and the Starkville (Oktibbeha County) area.

Mississippi↗

USGS1996

Floods in Central Texas, December 1991

Record-breaking peak discharges were recorded at eight U.S. Geological Survey (USGS) streamflow-gaging stations in central Texas during December 1991 (fig. 1), and substantial peak discharges also occurred at numerous other stations. Large peak discharges during December are unusual in central Texas. The rainfall causing the flooding began on December 18, with 6-day totals exceeding 10 inches (in.) in the area of heaviest rainfall. This report documents peak discharges and runoff volumes during December 1991. Recurrence intervals were determined for the peak discharges and runoff volumes for 1-, 3-, and 7-day periods. A recurrence interval references the approximate number of years during which a given peak discharge or runoff volumes is expected to be equaled or exceeded only once. A flood of a given recurrence interval is defined on the basis of peak discharge – for example, a 100-year flood is defined as the peak discharge that has a 1-percent chance of being equaled or exceeded in any given year.

Texas↗

USGS1997

Enhancements to the Branched Lagrangian Transport Modeling System

The Branched Lagrangian Transport Model (BLTM) has received wide use within the U.S. Geological Survey over the past 10 years. This report documents the enhancements and modifications that have been made to this modeling system since it was first introduced. The programs in the modeling system are arranged into five levels?programs to generate time-series of meteorological data (EQULTMP, SOLAR), programs to process time-series data (INTRP, MRG), programs to build input files for transport model (BBLTM, BQUAL2E), the model with defined reaction kinetics (BLTM, QUAL2E), and post processor plotting programs (CTPLT, CXPLT). An example application is presented to illustrate how the modeling system can be used to simulate 10 water-quality constituents in the Chattahoochee River below Atlanta, Georgia.

Water-Resources Investigations Report↗

USGS2010

A method for assessing carbon stocks, carbon sequestration, and greenhouse-gas fluxes in ecosystems of the United States under present conditions and future scenarios

he Energy Independence and Security Act of 2007 (EISA), Section 712, mandates the U.S. Department of the Interior to develop a methodology and conduct an assessment of the Nation’s ecosystems, focusing on carbon stocks, carbon sequestration, and emissions of three greenhouse gases (GHGs): carbon dioxide, methane, and nitrous oxide. The major requirements include (1) an assessment of all ecosystems (terrestrial systems, such as forests, croplands, wetlands, grasslands/shrublands; and aquatic ecosystems, such as rivers, lakes, and estuaries); (2) an estimate of the annual potential capacities of ecosystems to increase carbon sequestration and reduce net GHG emissions in the context of mitigation strategies (including management and restoration activities); and (3) an evaluation of the effects of controlling processes, such as climate change, land-use and land-cover change, and disturbances such as wildfires. The concepts of ecosystems, carbon pools, and GHG fluxes follow conventional definitions in use by major national and international assessment or inventory efforts. In order to estimate current ecosystem carbon stocks and GHG fluxes and to understand the potential capacity and effects of mitigation strategies, the method will use two time periods for the assessment: 2001 through 2010, which establishes a current ecosystem carbon and GHG baseline and will be used to validate the models; and 2011 through 2050, which will be used to assess potential capacities based on a set of scenarios. The scenario framework will be constructed using storylines of the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES), along with both reference and enhanced land-use and land-cover (LULC) and land-management parameters. Additional LULC and land-management mitigation scenarios will be constructed for each storyline to increase carbon sequestration and reduce GHG fluxes in ecosystems. Input from regional experts and stakeholders will be solicited to construct these scenarios. The methods for mapping the current LULC and ecosystem disturbances will require the extensive use of both remote-sensing data and field-survey data (for example, forest inventories) to capture and characterize landscape-changing events. For potential LULC changes and ecosystem disturbances, key drivers such as socioeconomic and climate changes will be used in addition to the biophysical data. The result of these analyses will be a series of maps for each future year for each scenario. These annual maps will form the basis for estimating carbon storage and GHG emissions. For terrestrial ecosystems, carbon storage, carbon-sequestration capacities, and GHG emissions under the present conditions and future scenarios will be assessed using the LULC-change and ecosystem-disturbance estimates in map format with a spatially explicit biogeochemical ensemble modeling system that incorporates properties of management activities (such as tillage or harvesting) and properties of individual ecosystems (such as energy exchange, vegetation characteristics, hydrological cycling, and soil attributes). For aquatic ecosystems, carbon burial in sediments and fluxes of GHG are functions of the present and future potential stream flow and sediment transport and will be assessed using empirical hydrological modeling methods. Validation and uncertainty analysis methods described in the methodology will follow established guidelines to assess the quality of the assessment results. The U.S. Environmental Protection Agency’s Level II ecoregions map will be the practical instrument for developing and delivering assessment results. Consequently, the ecoregion (there are 22 modified ecoregions) will be the reporting unit of the assessment because the scenarios, assessment results, validation, and uncertainty analysis will be produced at that scale. The implementation of these methods will require collaborations among various Federal agencies, State agencies, nongovernmental organizations, and the science community. Using the method described in this document, the assessment can be completed in approximately 3 to 4 years. The primary deliverables will be assessment reports containing tables, charts, and maps that will present the estimated GHG parameters annually for 2001 through 2050 by ecosystem, pool, and scenario. The results will permit the evaluation of a range of policies, mitigation options, and research topics, such as the demographic, LULC-change, or climate-change effects on carbon stocks, carbon sequestration, and GHG fluxes in ecosystems.

Scientific Investigations Report↗

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↗

USGS1983

Effect of the proposed Cooper River rediversion on sedimentation in Charleston Harbor, South Carolina

The rates of sedimentation and of resultant maintenance dredging in Charleston Harbor increased dramatically in the 1940s, following two major modifications to the harbor. One modification, the Santee-Cooper diversion project, caused a twentyfold increase in freshwater inflow to the harbor. The other modification was deepening of the navigation channels in the harbor from 30 to 35 feet below mean low water. After field and model studies indicated that the diversion was the major cause of the increase in the sedimentation rate, plans were made to redivert most of the Santee River water back to its former channel. This report documents a review of existing data and literature that was made to evaluate rediversion as a means of reducing the rate of maintenance dredging. The postrediversion decrease in the rate of maintenance dredging can be estimated only within broad limits because some important questions lack reliable answers. Analysis of available information indicates that rediversion will eventually reduce the rate of maintenance dredging by about 40 to 75 percent. The reduction in the rate of maintenance dredging may be delayed for a decade or more by the gradual removal of accumulated sediment and may be partially offset by the effects of future channel deepening.

South Carolina↗

USGS1995

Regional rainfall-runoff relations for simulation of streamflow for watersheds in Lake County, Illinois

Rainfall and streamflow data collected in Lake County, Ill., from March 1990 through September 1993 were used to (1) calibrate a rainfall-runoff model for an area encompassing three watersheds (individual areas of 17.2, 35.7, and 37.0 mi 2 (square miles) and (2) verify the regional model parameter set obtained from the calibration by applying the parameter set to rainfall-runoff models for an additional small (6.3 mi 2 ) watershed and a large (59.6 mi 2 ) watershed. In addition, rainfall and streamflow data collected from April 1991 through September 1993 were used to calibrate the rainfall-runoff model for three single land-use watersheds (38.2-305 acres), called hydrologic response units (HRU's). Significant differences were found between the best parameters used in the HRU models and in the larger watershed models. The main channels in the HRU's are intermittent streams; thus, the parameters in the HRU models were selected such that a fluctuating water table could be simulated; runoff from the larger watersheds is not as sensitive to the effects of a fluctuating water table. Classification of land cover into two pervious subareas (forest and grass) and one impervious subarea (including parking lots, streets, and rooftops, among others) was sufficient to simulate the rainfall-runoff relations for all watersheds accurately. The model parameters presented in this report, which were refined through regional calibration and verified for watersheds not considered in the calibration, allow simulation of runoff in watersheds in Lake County, Ill., with approximately 93-percent accuracy in the total water balance, an average absolute error in the annual- flow estimates of 10.9 percent (and an error rarely exceeding 25 percent for annual flow), and monthly water balances with correlation coefficients of 93 percent and coefficients of model-fit efficiency of 86 percent. The models closely reproduced the partial-duration series of runoff and storm-runoff frequencies for the modeled watersheds.

Illinois↗

USGS1996

Water-use analysis program for the Neshaminy Creek basin, Bucks and Montgomery counties, Pennsylvania

A water-use analysis computer program was developed for the Neshaminy Creek Basin to assist in managing and allocating water resources in the basin. The program was developed for IBM-compatible personal computers. Basin analysis and the methodologies developed for the Neshaminy Creek Basin can be transferred to other watersheds. The development and structure of the water-use analysis program is documented in this report. The report also serves as a user's guide. The program uses common relational database-management software that allows for water use-data input, editing, updating and output and can be used to generate a watershed water-use analysis report. The watershed-analysis report lists summations of public-supply well withdrawals; a combination of industrial, commercial, institutional, and ground-water irrigation well withdrawals; spray irrigation systems; a combination of public, industrial, and private surface-water withdrawals; wastewater-tratement-facility dishcarges; estimates of aggregate domestic ground-water withdrawals on an areal basin or subbasin basis; imports and exports of wastewater across basin or subbasin divides; imports and exports of public water supplies across basin or subbasin divides; estimates of evaporative loss and consumptive loss from produce incorporation; industrial septic-system discharges to ground water; and ground-water well-permit allocations.

Pennsylvania↗