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USGS2009

Population Dynamics of Adult Lost River (Deltistes luxatus) and Shortnose (Chasmistes brevirostris) Suckers in Clear Lake Reservoir, California, 2006-08

We report results from ongoing research into the population dynamics of endangered Lost River and shortnose suckers in Clear Lake Reservoir, California. Results are included for sampling that occurred from fall 2006 to spring 2008. We summarize catches and passive integrated transponder tagging efforts from trammel net sampling in fall 2006 and fall 2007, and report on detections of tagged suckers on remote antennas in the primary spawning tributary, Willow Creek, in spring 2007 and spring 2008. Results from trammel net sampling were similar to previous years, although catches of suckers in fall 2006 were lower than in 2007 and past years. Lost River and shortnose suckers combined made up about 80 percent of the sucker catch in each year, and more than 2,000 new fish were tagged across the 2 years. Only a small number of the suckers captured in fall sampling were recaptures of previously tagged fish, reinforcing the importance of remote detections of fish for capture-recapture analysis. Detections of tagged suckers in Willow Creek were low in spring 2007, presumably because of low flows. Nonetheless, the proportions of tagged fish that were detected were reasonably high and capture-recapture analyses should be possible after another year of data collection. Run timing for Lost River and shortnose suckers was well described by first detections of individuals by antennas in Willow Creek, although we may not have installed the antennas early enough in 2008 to monitor the earliest portion of the Lost River sucker migration. The duration and magnitude of the spawning runs for both species were influenced by flows and water temperature. Flows in Willow Creek were much higher in 2008 than in 2007, and far more detections were recorded in 2008 and the migrations were more protracted. In both years and for both species, migrations began in early March at water temperatures between 5 and 6 deg C and peaks were related to periods of increasing water temperature. The sex ratio of Lost River suckers detected in Willow Creek was skewed toward males, despite consistently more females having been tagged in fall sampling. This pattern indicates that some tagged female Lost River suckers may be spawning elsewhere in the system, and we intend to investigate this possibility to verify or alter the representativeness of our spring monitoring. Length frequency analysis of fall trammel net catches showed that the populations of both species in Clear Lake Reservoir have undergone major demographic transitions during the last 15 years. In the mid-1990s, the populations were dominated by larger fish and showed little evidence of recent recruitment. These larger fish apparently disappeared in the late 1990s and early 2000s, and the populations are now dominated by fish that recruited into the adult populations in the late 1990s. The length frequencies from the last 4 years provide evidence of consistent recruitment into the Lost River sucker population, but provide no such evidence for the shortnose sucker population. Overall, annual growth rates for both species in Clear Lake were 2-4 times greater than growth rates for conspecifics in Upper Klamath Lake. However, little or no growth occurred for either species in Clear Lake between 2006 and 2007. Based on available evidence, we are unable to fully explain differences in growth rates between systems or among years within Clear Lake.

Open-File Report↗

USGS2017

Reassessing rainfall in the Luquillo Mountains, Puerto Rico: Local and global ecohydrological implications

Mountains receive a greater proportion of precipitation than other environments, and thus make a disproportionate contribution to the world’s water supply. The Luquillo Mountains receive the highest rainfall on the island of Puerto Rico and serve as a critical source of water to surrounding communities. The area’s role as a long-term research site has generated numerous hydrological, ecological, and geological investigations that have been included in regional and global overviews that compare tropical forests to other ecosystems. Most of the forest- and watershed-wide estimates of precipitation (and evapotranspiration, as inferred by a water balance) have assumed that precipitation increases consistently with elevation. However, in this new analysis of all known current and historical rain gages in the region, we find that similar to other mountainous islands in the trade wind latitudes, leeward (western) watersheds in the Luquillo Mountains receive lower mean annual precipitation than windward (eastern) watersheds. Previous studies in the Luquillo Mountains have therefore overestimated precipitation in leeward watersheds by up to 40%. The Icacos watershed, however, despite being located at elevations 200–400 m below the tallest peaks and to the lee of the first major orographic barrier, receives some of the highest precipitation. Such lee-side enhancement has been observed in other island mountains of similar height and width, and may be caused by several mechanisms. Thus, the long-reported discrepancy of unrealistically low rates of evapotranspiration in the Icacos watershed is likely caused by previous underestimation of precipitation, perhaps by as much as 20%. Rainfall/runoff ratios in several previous studies suggested either runoff excess or runoff deficiency in Luquillo watersheds, but this analysis suggests that in fact they are similar to other tropical watersheds. Because the Luquillo Mountains often serve as a wet tropical archetype in global assessments of basic ecohydrological processes, these revised estimates are relevant to regional and global assessments of runoff efficiency, hydrologic effects of reforestation, geomorphic processes, and climate change.

Luquillo Mountains↗

USGS2014

Assessment of conservation easements, total phosphorus, and total suspended solids in West Fork Beaver Creek, Minnesota, 1999-2012

This study examined conservation easements and their effectiveness at reducing phosphorus and solids transport to streams. The U.S. Geological Survey cooperated with the Minnesota Board of Water and Soil Resources and worked collaboratively with the Hawk Creek Watershed Project to examine the West Fork Beaver Creek Basin in Renville County, which has the largest number of Reinvest In Minnesota land retirement contracts in the State (as of 2013). Among all conservation easement programs, a total of 24,218 acres of agricultural land were retired throughout Renville County, and 2,718 acres were retired in the West Fork Beaver Creek Basin from 1987 through 2012. Total land retirement increased steadily from 1987 until 2000. In 2000, land retirement increased sharply because of the Minnesota River Conservation Reserve Enhancement Program, then leveled off when the program ended in 2002. Streamflow data were collected during 1999 through 2011, and total phosphorus and total suspended solids data were collected during 1999 through 2012. During this period, the highest peak streamflow of 1,320 cubic feet per second was in March 2010. Total phosphorus and total suspended solids are constituents that tend to increase with increases in streamflow. Annual flow-weighted mean total-phosphorus concentrations ranged from 0.140 to 0.759 milligrams per liter, and annual flow-weighted mean total suspended solids concentrations ranged from 21.3 to 217 milligrams per liter. Annual flow-weighted mean total phosphorus and total suspended solids concentrations decreased steadily during the first 4 years of water-quality sample collection. A downward trend in flow-weighted mean total-phosphorus concentrations was significant from 1999 through 2008; however, flow-weighted total-phosphorus concentrations increased substantially in 2009, and the total phosphorus trend was no longer significant. The high annual flow-weighted mean concentrations for total phosphorus and total suspended solids in 2009 were affected by outlier concentrations documented in March 2009. Agricultural land-retirement data only were available through 2008; therefore, it was not possible to compare total phosphorus and total suspended solids concentrations to agricultural land-retirement data for 2009–11. A downward trend in annual flow-weighted mean total-phosphorus concentrations was related significantly to annual land retirement for 1999–2008. The relation between annual flow-weighted mean total suspended solids concentration and annual land retirement was not statistically significant for 1999–2008. If land-retirement data had been available for 2009–11, it is possible that the relation between total phosphorus and land retirement would no longer be evident because of the marked increase in flow-weighted concentrations during 2009. Alternatively, the increase in annual flow-weighted mean total-phosphorus concentrations during 2009–11 may be because of other factors, including industrial discharges, increases in drain tile installation, changes in land use including decreases in agricultural land retirement after 2008, increases in erosion, increases in phosphorus applications to fields, or unknown causes. Inclusion of land-retirement effects in agency planning along with other factors adds perspective with regard to the broader picture of interdependent systems and allows agencies to make informed decisions on the benefits of perpetual easements compared to limited duration easements.

Minnesota↗

USGS2022

Application of a soil-water-balance model to estimate annual groundwater recharge for Long Island, New York, 1900–2019

A soil-water-balance (SWB) model was developed for Long Island, New York, to estimate the potential amount of annual groundwater recharge to the Long Island aquifer system from 1900 to 2019. The SWB model program is a computer code based on a modified Thornthwaite-Mather SWB approach and uses spatially and temporally distributed meteorological, land-cover, and soil properties as input to compute potential daily groundwater recharge. Simulated outputs indicate that island-wide potential groundwater recharge trends, as a percentage of precipitation, have increased approximately 3 percent during the 120-year period. The simulated results account for both climatic and land-cover changes that have occurred during the period. A change from undeveloped (forested land cover) to low- and medium-density residential land cover or land use increased potential groundwater recharge because of a decrease in evapotranspiration. During the 30-year period from 1900 to 1930, the simulated potential average groundwater recharge rate on Long Island was estimated to be 18.50 inches per year (in/yr), or a total of 1,243 million gallons per day, during the 30-year period from 1985 to 2015, the simulated potential average groundwater recharge rate estimate increased to 20.73 in/yr (a total of around 1,393 million gallons per day). During the 1900–2019 simulation period, the potential average annual groundwater recharge rate was about 19.24 in/yr. The data for that period included values for a 3-year meteorological drought from 1963 to 1965, where the mean precipitation was about 26.5 percent lower than the long-term average of 46.7 in/yr, and the potential groundwater recharge rate was about 12.3 in/yr. During a 3-year wet period from 1982 to 1984, where mean precipitation was about 19.6 percent higher than the long-term average, the estimated potential groundwater recharge rate was about 26.8 in/yr.

New York↗

USGS2024

Federal lands greenhouse gas emissions and sequestration in the United States: Estimates for 2005–22

In 2016, the Secretary of the U.S. Department of the Interior requested that the U.S. Geological Survey (USGS) produce a publicly available and annually updated database of estimated greenhouse gas emissions associated with the extraction and use of fossil fuels from Federal lands. The first report in this series included emissions estimates from 2005 to 2014 and were reported for 29 States and two offshore areas. Native American and Tribal lands were not included in that analysis. This report recalculates those previous years (2005–14) with updated data and methods and extends the estimates to 2022. Nationwide emissions from fossil fuels produced on Federal lands in 2022 were 1,081.2 million metric tons of carbon dioxide equivalent (MMT CO 2 Eq.) for CO 2 , 33.4 MMT CO 2 Eq. for methane (CH 4 ), and 4.3 MMT CO 2 Eq. for nitrous oxide (N 2 O). Compared to 2005, the 2022 totals represent decreases in emissions for all three greenhouse gases (by 17 percent for CO 2 , 37 percent for CH 4 , and 30 percent for N 2 O). Emissions from fossil fuels produced on Federal lands represent, on average, 21.8 percent of U.S. emissions for CO 2 , 6.1 percent for CH 4 , and 1.3 percent for N 2 O over the 18 years included in this estimate. The trends and relative magnitudes of the greenhouse gas emissions estimated are roughly parallel to the Federal lands fossil fuel production volumes. In 2021, Federal lands of the conterminous United States stored 70,424 MMT CO 2 Eq. in terrestrial ecosystems. Soils stored most of the terrestrial ecosystem carbon (66 percent), followed by live vegetation (25 percent), deadwood (5 percent), and litter (4 percent). Carbon sequestration on Federal lands was highly variable over time, owing primarily to interannual variability in climate and weather, and variability in land use and land cover (LULC) change and disturbances, among these are wildfires and logging. Between 2005 and 2021, Federal lands sequestered an average of 83 MMT CO 2 Eq./yr. By subtracting the cumulative effects of LULC and disturbance-related CO 2 losses to the atmosphere from the total, we estimate that ecosystems at the national level sequestered CO 2 at an annual mean rate of 17 MMT CO 2 Eq./yr in a term called the net ecosystem exchange (NEE). This annual NEE sequestration value represents about 1.4 percent of average fossil fuel emissions over the same period. The USGS estimates presented in this report represent an accounting for the emissions resulting from fossil fuel extraction on Federal lands and the end-use combustion of those fuels, as well as for the sequestration of carbon in terrestrial ecosystems on Federal lands. A combined net CO 2 emissions estimate, which is the difference between the emitted and sequestered CO 2 from both the fossil fuel and ecosystems estimates, provides context for evaluating the greenhouse gas contributions of activities on these lands. The estimates included in this report can provide context for future energy decisions, as well as a basis to track change in the future.

Scientific Investigations Report↗

USGS1984

Ground-water resources of the Mattapoisett River Valley, Plymouth County, Massachusetts

Ground-water withdrawals by municipal wells in the Mettapoisett River valley, Massachusetts, are expected to triple in the next two decades. State and local concern about the long-term impacts of these withdrawals on ground-water levels and streamflow made it necessary to assess the ground-water resources of the valley and to develop a digital ground-water-flow model for management purposes. Ten pumping scenarios, which represent the present and proposed withdrawals from the aquifer, were simulated using reduced recharge conditions. Under conditions simulating 1965 average annual recharge, predicted water levels in the aquifer are as much as 9 feet lower than average annual levels. At the highest withdrawal rates, the predicted drawdown in four wells exceeds the estimated available drawdown. Under conditions representative of the 7-day 10-year low flow of the river, predicted water levels decline as much as 19 feet. Simulated withdrawals in six scenarios use all of the available ground-water discharge. If this drought condition should occur and streamflow is not supplemented by surface water, the model results indicate that the river in the southern half of the valley will stop flowing under most pumping plans. (USGS)

Water-Resources Investigations Report↗

USGS1984

Gazetteer of hydrologic characteristics of streams in Massachusetts — Coastal river basins of the North Shore and Massachusetts Bay

The coastal river basins of the North Shore and Boston Bay include streams draining the Parker River (60.4 square miles), Rowley River (9.9 square miles), Ipswich River (156 miles), Mystic River (66.0 square miles), Charles River (311 square miles), Neponset River (117 square miles), Weymouth Fore and Weymouth Back Rivers (about 63 square miles) and Weir River (about 20 square miles) basins. The study area in eastern and northeastern Massachusetts also includes the minor river basins draining into Massachusetts Bay, Ipswich Bay, or the Atlantic Ocean. Drainage areas using the latest available 1:24,000 scale topographic maps were computed for the first time for streams draining more than 3 square miles and were recomputed for data-collection sites. Streamflow characteristics at 15 gaging stations were calculated using a new data base with daily flow records through 1981. These characteristics include annual and monthly flow statistics, duration of daily flow values, and the annual 7-day mean low flow at the 2-year and 10-year recurrence intervals. Seven-day low-flow statistics are presented for 95 partial-record sites and the procedures used to determine the hydrologic characteristics of a basin are summarized. Basin characteristics representing 14 commonly used indices to estimate various streamflows are presented for 15 gaged streams. This gazetteer will aid in the planning and siting of water-resources related activities and will provide a common data base for governmental agencies and the engineering and planning communities. (USGS)

Massachusetts↗

USGS2006

Use of sediment rating curves and optical backscatter data to characterize sediment transport in the Upper Yuba River watershed, California, 2001-03

Sediment transport in the upper Yuba River watershed, California, was evaluated from October 2001 through September 2003. This report presents results of a three-year study by the U.S. Geological Survey, in cooperation with the California Ecosystem Restoration Program of the California Bay-Delta Authority and the California Resources Agency. Streamflow and suspended-sediment concentration (SSC) samples were collected at four gaging stations; however, this report focuses on sediment transport at the Middle Yuba River (11410000) and the South Yuba River (11417500) gaging stations. Seasonal suspended-sediment rating curves were developed using a group-average method and non-linear least-squares regression. Bed-load transport relations were used to develop bed-load rating curves, and bed-load measurements were collected to assess the accuracy of these curves. Annual suspended-sediment loads estimated using seasonal SSC rating curves were compared with previously published annual loads estimated using the Graphical Constituent Loading Analysis System (GCLAS). The percent difference ranged from -85 percent to +54 percent and averaged -7.5 percent. During water year 2003 optical backscatter sensors (OBS) were installed to assess event-based suspended-sediment transport. Event-based suspended-sediment loads calculated using seasonal SSC rating curves were compared with loads calculated using calibrated OBS output. The percent difference ranged from +50 percent to -369 percent and averaged -79 percent. The estimated average annual sediment yield at the Middle Yuba River (11410000) gage (5 tons/mi2) was significantly lower than that estimated at the South Yuba River (11417500) gage (14 tons/mi2). In both rivers, bed load represented 1 percent or less of the total annual load throughout the project period. Suspended sediment at the Middle Yuba River (11410000) and South Yuba River (11417500) gages was typically greater than 85 percent silt and clay during water year 2003, and sand concentrations at the South Yuba River (11417500) gage were typically higher than those at the Middle Yuba River (11410000) gage for a given streamflow throughout the three year project period. Factors contributing to differences in sediment loads and grain-size distributions at the Middle Yuba River (11410000) and South Yuba River (11417500) gages include contributing drainage area, flow diversions, and deposition of bed-material-sized sediment in reservoirs upstream of the Middle Yuba River (11410000) gage. Owing to its larger drainage area, higher flows, and absence of man-made structures that restrict sediment movement in the lower basin, the South Yuba River transports a greater and coarser sediment load.

Scientific Investigations Report↗

USGS1968

Water resources data for Arizona, 1968: Part 2. Water quality records

Water-resources investigations of the U.S. Geological Survey include the collection of water-quality data on the chemical and physical characteristics of surface and groundwater supplies of the Nation. These data for the 1968 water year for the quality of surface waters in Arizona are presented in this report. The data were collected by the Water Resources Division of the U.S. Geological Survey under the direction of H. M. Babcock, district chief. Water-quality information is presented for chemical quality, fluvial sediment, and water temperatures. The chemical quality includes concentrations of individual dissolved constituents and certain properties or characteristics, such as hardness, sodium-adsorption ratio, specific conductance, and pH. Fluvial-sediment information is given for suspended-sediment discharges and concentrations and for particle-size distribution of suspended sediment and bed material. Water-temperature data represent once-daily observations, except for stations where a continuous temperature recorder furnishes information from which daily minimums and maximums are obtained. The Geological Survey published the annual series of water supply papers, "Quality of Surface Waters of the United States," from 1941 through 1963, which contained the chemical-quality. temperature, and suspended-sediment data of the water. Each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records for Arizona are contained in part 9 of the water-supply paper series. (See table, p. 13.) These publications are available in most public libraries. Beginning with the 1964 water year, water-quality records for surface water obtained by the Geological Survey have been published in a new series of annual releases on a State boundary basis. These reports are primarily for local and immediate use, and their distribution is limited. The records also will be published in Geological Survey water-supply papers.

Arizona↗

USGS1992

Techniques for estimating 7-day, 10-year low-flow characteristics for ungaged sites on streams in Mississippi

Mississippi State water laws require that the 7-day, 10-year low-flow characteristic (7Q10) of streams be used as a criterion for issuing wastedischarge permits to dischargers to streams and for limiting withdrawals of water from streams. This report presents techniques for estimating the 7Q10 for ungaged sites on streams in Mississippi based on the availability of baseflow discharge measurements at the site, location of nearby gaged sites on the same stream, and drainage area of the ungaged site. These techniques may be used to estimate the 7Q10 at sites on natural, unregulated or partially regulated, and non-tidal streams. Low-flow characteristics for streams in the Mississippi River alluvial plain were not estimated because the annual lowflow data exhibit decreasing trends with time. Also presented are estimates of the 7Q10 for 493 gaged sites on Mississippi streams. Techniques for estimating the 7Q10 have been developed for ungaged sites with base-flow discharge measurements, for ungaged sites on gaged streams, and for ungaged sites on ungaged streams. For an ungaged site with one or more base-flow discharge measurements, base-flow discharge data at the ungaged site are related to concurrent discharge data at a nearby gaged site. For ungaged sites on gaged streams, several methods of transferring the 7Q10 from a gaged site to an ungaged site were developed; the resulting 7Q10 values are based on drainage area prorations for the sites. For ungaged sites on ungaged streams, the 7Q10 is estimated from a map developed for. this study that shows the unit 7Q10 (7Q10 per square mile of drainage area) for ungaged basins in the State. The mapped values were estimated from the unit 7Q10 determined for nearby gaged basins, adjusted on the basis of the geology and topography of the ungaged basins.

Mississippi↗

USGS2006

Selected Streamflow Statistics and Regression Equations for Predicting Statistics at Stream Locations in Monroe County, Pennsylvania

A suite of 28 streamflow statistics, ranging from extreme low to high flows, was computed for 17 continuous-record streamflow-gaging stations and predicted for 20 partial-record stations in Monroe County and contiguous counties in north-eastern Pennsylvania. The predicted statistics for the partial-record stations were based on regression analyses relating inter-mittent flow measurements made at the partial-record stations indexed to concurrent daily mean flows at continuous-record stations during base-flow conditions. The same statistics also were predicted for 134 ungaged stream locations in Monroe County on the basis of regression analyses relating the statistics to GIS-determined basin characteristics for the continuous-record station drainage areas. The prediction methodology for developing the regression equations used to estimate statistics was developed for estimating low-flow frequencies. This study and a companion study found that the methodology also has application potential for predicting intermediate- and high-flow statistics. The statistics included mean monthly flows, mean annual flow, 7-day low flows for three recurrence intervals, nine flow durations, mean annual base flow, and annual mean base flows for two recurrence intervals. Low standard errors of prediction and high coefficients of determination (R2) indicated good results in using the regression equations to predict the statistics. Regression equations for the larger flow statistics tended to have lower standard errors of prediction and higher coefficients of determination (R2) than equations for the smaller flow statistics. The report discusses the methodologies used in determining the statistics and the limitations of the statistics and the equations used to predict the statistics. Caution is indicated in using the predicted statistics for small drainage area situations. Study results constitute input needed by water-resource managers in Monroe County for planning purposes and evaluation of water-resources availability.

Scientific Investigations Report↗

USGS2016

Environmental conditions in the Namskaket Marsh Area, Orleans, Massachusetts: A summary of studies by the U.S. Geological Survey, 1989–2011

Namskaket Marsh and its tidal creek system are potential receptors for a treated wastewater plume originating from a septage treatment facility in the northwest part of Orleans, Massachusetts, on Cape Cod. From 1989 to 2011, the U.S. Geological Survey, in cooperation with State and local partners, conducted a series of studies in the Namskaket Marsh area to characterize the potential effects of the plume on the marsh and its tidal creek system. Studies included characterizing the baseline vegetation and salinity distribution in the marsh, monitoring the movement of the wastewater plume downgradient of the septage treatment facility, and sampling nutrient concentrations in the tidal creek system during a baseline period prior to the arrival of the plume at the marsh boundary. The Inner Namskaket Marsh baseline vegetation survey in 1995 found it to be dominated by Phragmites australis (common reed, 44 percent of vegetative cover), Spartina patens (salt marsh hay, 17 percent), and Spartina alterniflora (cordgrass, 9 percent). Phragmites occurrence was correlated with shallow pore-water salinity in the marsh peat and was largely confined to areas with salinities less than 4 parts per thousand. Baseline, ebb-tide nutrient concentrations at the tidal creek sampling stations during 1994–96 showed strong seasonal variations for ammonium, likely associated with the seasonal cycle of growth and senescence for the dominant salt marsh grasses ( S. alterniflora and S. patens ). The seasonal cycle for nitrate was generally less pronounced. The movement of the wastewater plume has been monitored from its source at the septage treatment facility to areas immediately adjacent to and beneath the most inland part of the marsh. In late 1994, the plume was first detected by borehole geophysical logging in observation wells along the Cape Cod Rail Trail (rail trail), 600 feet northwest of the infiltration beds, at an elevation of 47 to 53 feet below the National Geodetic Vertical Datum of 1929 (NGVD 29). At the rail trail, the plume was largely confined below a 3- to 8-foot-thick silt/clay layer detected by borehole geophysical logging and confirmed by lithologic samples. By early 1998, a second plume segment was detected above this silt/clay layer at the rail trail, near the plume’s southwest boundary. Groundwater sampling in 2003–4 at additional stations southwest of the main plume, as well as beneath Namskaket Marsh, defined the extent of this shallow plume segment in glacial sands underlying the marsh. The tidal creek sampling stations established in the 1990s were resampled in 2003–4 and 2010–11 to evaluate potential effects of the treated wastewater plume on creek water quality. The annual medians of the 2011 biweekly nitrate and total dissolved nitrogen concentrations were determined for each station and compared to the annual medians of biweekly samples for the baseline years 1994, 1995, and 1996. At all stations, the 2011 median nitrate concentrations were within the range of medians for the 3 baseline years. A similar result was obtained for total dissolved nitrogen. We conclude that the 2011 creek samples, collected approximately 8 years after the shallow plume segment was first detected beneath the marsh, do not show evidence of elevated nitrate or total dissolved nitrogen concentrations attributable to discharge of either the shallow or deep segments of the treated wastewater plume.

Massachusetts↗

USGS2002

Stream-aquifer relations and the potentiometric surface of the Upper Floridan aquifer in the lower Apalachicola-Chattahoochee-Flint River basin in parts of Georgia, Florida, and Alabama, 1999-2000

The Upper Floridan aquifer is the principal source of water for domestic and agricultural use in the lower Apalachicola-Chattahoochee-Flint (ACF) River Basin. Recent drought and increased water use have made understanding surface- and ground-water relations a priority for water-resource managers in the region. From July 1999 through August 2000, less than normal precipitation reduced streamflow in the area to less than 12 percent of average mean-daily streamflow and ground-water levels reached record or near-record lows. Effects of drought on stream-aquifer interactions in the basin were evaluated using baseflow estimation, ground-water seepage calculations, and potentiometric-surface maps. Ground-water discharge to streams, or baseflow, was estimated using three methods: field measurements, hydrograph separation, and linear regression analysis. Results were evaluated seasonally -- October 1999, April 2000, and August 2000 -- and for the period of record at four surface-water stations located on Kinchafoonee, Spring, Muckalee, and Turkey Creeks. Estimates of baseflow also were compared annually; ground-water discharge during the drought years, 1999 - 2000, was compared with ground-water discharge during a relatively wet year, 1994. Hydrograph separation indicated decreased base-flow of streams as the water level in the Upper Floridan aquifer declined. Mean-annual baseflow for Kinchafoonee, Spring, Muckalee, and Turkey Creeks ranged from 36 to 71 percent of total streamflow during the period of record. In 1994 baseflow accounted for only 37 to 56 percent of total streamflow, in 1999 baseflow comprised from 60 to 73 percent of total streamflow, and in 2000 baseflow comprised from 56 to 76 percent of streamflow. The percentage of total streamflow attributed to ground water increased during the drought, whereas other components of streamflow decreased (overland flow, interflow, and channel precipitation). Even though relative ground-water contributions were increased, the volume of water discharged from the aquifer to streams decreased during the drought as the Upper Floridan aquifer water level declined. Unit-area mean-annual ground-water discharge ranged from 0.60 to 0.79 cubic foot per second per square mile ([ft 3 /s]/mi2) in 1994, from 0.24 to 0.58 (ft 3 /s)/mi2 in 1999, and from 0.13 to 0.33 (ft 3 /s)/mi2 in 2000. Ground-water contributions to streamflow are high in winter, when evaporative demands are low, and low in summer, when evaporative demands are high. Linear regression analysis of stream-aquifer relations in the lower ACF River Basin shows 85- or 90-percent flow durations as reasonable estimates of baseflow.

Alabama, Florida, Georgia↗

USGS1997

Hydrologic and water-quality conditions in the Horse Creek basin, west-central Florida, October 1992-February 1995

A baseline study of the 241-square-mile Horse Creek basin was undertaken from October 1992 to February 1995 to assess the hydrologic and water-quality conditions of one of the last remaining undeveloped basins in west-central Florida. During the period of the study, much of the basin remained in a natural state, except for limited areas of cattle and citrus production and phosphate mining. Rainfall in 1993 and 1994 in the Horse Creek basin was 8 and 31 percent, respectively, above the 30-year long-term average. The lowest and highest maximum instantaneous peak discharge of the six daily discharge stations occurred at the Buzzard Roost Branch and the Horse Creek near Arcadia stations with 185 to 4,180 cubic feet per second, respectively. The Horse Creek near Arcadia station had the lowest number of no-flow days with zero days and the Brushy Creek station had the highest number with 113 days. During the study, the West Fork Horse Creek subbasin had the highest daily mean discharge per square mile with 30.6 cubic feet per second per square mile, and the largest runoff coefficient of 43.7 percent. The Buzzard Roost Branch subbasin had the lowest daily mean discharge per square mile with 5.05 cubic feet per second per square mile, and Brushy Creek and Brandy Branch shared the lowest runoff coefficient of 0.6 percent. Brandy Branch had the highest monthly mean runoff in both 1993 and 1994 with 11.48 and 19.28 inches, respectively. During the high-baseflow seepage run, seepage gains were 8.87 cubic feet per second along the 43-mile Horse Creek channel. However, during the low-baseflow seepage run, seepage losses were 0.88 cubic foot per second. Three methods were used to estimate average annual ground-water recharge in the Horse Creek basin: (1) well hydrograph, (2) chloride mass balance, and (3) streamflow hydrograph. Estimated average annual recharge using these three methods ranged from 3.6 to 8.7 inches. The high percentage of carbonate plus bicarbonate analyzed at the Carlton surficial aquifer well could indicate an upward ground-water flow from the underlying intermediate aquifer system. Based on constituent concentrations in water samples from the six daily discharge stations, concentrations generally are lower in the upper three subbasins, West Fork Horse Creek, Upper Horse Creek, and Brushy Creek than in the lower three subbasins. Typically, concentrations were highest for major ions at Buzzard Roost Branch and nutrients at Brushy Creek.

Florida↗

USGS2003

Hydrogeology and Ground-Water Quality of Brunswick County, North Carolina

Brunswick County is the southernmost coastal county in North Carolina and lies in the southeastern part of the Coastal Plain physiographic province. In this report, geologic, hydrologic, and chemical data were used to investigate and delineate the hydrogeologic framework and ground-water quality of Brunswick County. The major aquifers and their associated confining units delineated in the Brunswick County study area include, from youngest to oldest, the surficial, Castle Hayne, Peedee, Black Creek, upper Cape Fear, and lower Cape Fear aquifers. All of these aquifers, with the exception of the Castle Hayne aquifer, are located throughout Brunswick County. The Castle Hayne aquifer extends across only the southeastern part of the county. Based on available data, the Castle Hayne and Peedee confining units are missing in some areas of Brunswick County, which allows direct hydraulic contact between the surficial aquifer and underlying Castle Hayne or Peedee aquifers. The confining units for the Black Creek, upper Cape Fear, and lower Cape Fear aquifers appear to be continuous throughout Brunswick County. In examining the conceptual hydrologic system for Brunswick County, a generalized water budget was developed to better understand the natural processes, including precipitation, evapotranspiration, and stream runoff, that influence ground-water recharge to the shallow aquifer system in the county. In the generalized water budget, an estimated 11 inches per year of the average annual precipitation of 55 inches per year in Brunswick County is estimated to infiltrate and recharge the shallow aquifer system. Of the 11 inches per year that recharges the shallow system, about 1 inch per year is estimated to recharge the deeper aquifer system. The surficial aquifer in Brunswick County is an important source of water for domestic supply and irrigation. The Castle Hayne aquifer is the most productive aquifer and serves as the principal ground-water source of municipal supply for the county. The upper part of the Peedee aquifer is an important source of ground-water supply for domestic and commercial use. Ground water in the lower part of the Peedee aquifer and the underlying aquifers is brackish and is not known to be used as a source of supply in Brunswick County. Most of the precipitation that recharges the surficial aquifer is discharged to local streams that drain into the Waccamaw River, Cape Fear River, and Atlantic Ocean. Recharge to the Castle Hayne aquifer occurs primarily from the surficial aquifer. Recharge to the Peedee aquifer occurs primarily from the surficial and Castle Hayne aquifers, with some upward leakage of water also occurring from the underlying Black Creek aquifer. Discharge from the Castle Hayne and Peedee aquifers occurs to local streams, the Cape Fear River, and the Atlantic Ocean. Evaluation of water-level data for the period January 1970 through May 2002 indicated no apparent long-term temporal trends in water levels in the surficial and Castle Hayne aquifers and in the upper part of the Peedee aquifer. The most significant water-level trends were noted for wells tapping the lower part of the Peedee aquifer and tapping the Black Creek aquifer where water levels have declined as much as 41 and 37 feet, respectively. These ground-water-level declines are attributed to regional ground-water pumping in areas outside of Brunswick County. Water-level data for Brunswick County wells tapping the upper Cape Fear and lower Cape Fear aquifers tend to fluctuate within a fairly uniform range with no apparent temporal trend noted. Analysis of vertical hydraulic gradients during this same period primarily indicate downward flow of ground water within and among the surficial, Castle Hayne, and Peedee aquifers. The vertical flow of ground water in the Black Creek aquifer is upward into the overlying Peedee aquifer. Upward flow also is noted for the upper and lower Cape Fear aquifers. Historic and recent analytic data were evaluated to better understand the sources of water contained in Brunswick County aquifers and the suitability of the water for consumption. Based on analytical results obtained for recent samples collected during this study, ground water from the surficial aquifer, Castle Hayne aquifer, and upper part of the Peedee aquifer appears to be generally suitable for drinking water. Although concentrations of iron and manganese commonly exceeded the drinking-water standards, the concern generally associated with the occurrence of these analytes in a water supply is one of aesthetics. In all samples, nitrate, nitrite, and sulfate were detected at concentrations less than drinkingwater standards. Based on historic analytical data, the brackish water in the lower part of the Peedee aquifer and in the Black Creek, upper Cape Fear, and lower Cape Fear aquifers is classified as a sodium-chloride type water. The presence of brackish water in these deeper systems combined with upward vertical gradients presents the potential for upward migration of brackish water into overlying aquifers, or upconing beneath areas of pumping. The current (2001) location of the boundary between freshwater and brackish water in Brunswick County aquifers is unknown.

North Carolina↗

USGS2015

Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California: 2014

Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica ), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer (km) south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, Calif. This report includes the data collected by U.S. Geological Survey (USGS) scientists for the period January 2014 to December 2014. These append to long-term datasets extending back to 1974, and serve as the basis for the City of Palo Alto’s Near-Field Receiving Water Monitoring Program, initiated in 1994. Following significant reductions in the late 1980s, silver (Ag) and copper (Cu) concentrations in sediment and M. petalum appear to have stabilized. Data for other metals, including chromium (Cr), mercury (Hg), nickel (Ni), selenium (Se), and zinc (Zn), have been collected since 1994. Over this period, concentrations of these elements have remained relatively constant, aside from seasonal variation that is common to all elements. In 2014, concentrations of Ag and Cu in M. petalum varied seasonally in response to a combination of site-specific metal exposures and annual growth and reproduction, as reported previously. Seasonal patterns for other elements, including Cr, Ni, Zn, Hg, and Se, were generally similar in timing and magnitude as those for Ag and Cu. In M. petalum , all observed elements showed annual maxima in January–February and minima in April, except for Zn, which was lowest in December. In sediments, annual maxima also occurred in January–February, and minima were measured in June and September. In 2014, metal concentrations in both sediments and clam tissue were among the lowest on record. This record suggests that regional-scale factors now largely control sedimentary and bioavailable concentrations of Ag and Cu, as well as other elements of regulatory interest, at the Palo Alto site. Analyses of the benthic community structure of a mudflat in South San Francisco Bay over a 40-year period show that changes in the community have occurred concurrent with reduced concentrations of metals in the sediment and in the tissues of the biosentinel clam, M. petalum , from the same area. Analysis of M. petalum shows increases in reproductive activity concurrent with the decline in metal concentrations in the tissues of this organism. Reproductive activity is presently stable (2014), with almost all animals initiating reproduction in the fall and spawning the following spring. The entire infaunal community has shifted from being dominated by several opportunistic species to a community where the species are more similar in abundance, a pattern that indicates a more stable community that is subjected to fewer stressors. In addition, two of the opportunistic species ( Ampelisca abdita and Streblospio benedicti ) that brood their young and live on the surface of the sediment in tubes have shown a continual decline in dominance coincident with the decline in metals; both species had short-lived rebounds in abundance in 2008, 2009, and 2010. Heteromastus filiformis (a subsurface polychaete worm that lives in the sediment, consumes sediment and organic particles residing in the sediment, and reproduces by laying its eggs on or in the sediment) showed a concurrent increase in dominance and, in the last several years before 2008, showed a stable population. H. filiformis abundance increased slightly in 2011–2012 and returned to pre-2011 numbers in 2014. An unidentified disturbance occurred on the mudflat in early 2008 that resulted in the loss of the benthic animals, except for deep-dwelling animals like Macoma petalum . However, within two months of this event animals returned to the mudflat. The resilience of the community suggested that the disturbance was not due to a persistent toxin or to anoxia. The reproductive mode of most species present in 2014 is reflective of species that were available either as pelagic larvae or as mobile adults. Although oviparous species were lower in number in this group, the authors hypothesize that these species will return slowly as more species move back into the area. The use of functional ecology was highlighted in the 2014 benthic community data, which showed that the animals that have now returned to the mudflat are those that can respond successfully to a physical, nontoxic disturbance. Today, community data show a mix of species that consume the sediment, or filter feed, have pelagic larvae that must survive landing on the sediment, and those that brood their young. USGS scientists view the 2008 disturbance event as a response by the infaunal community to an episodic natural stressor (possibly sediment accretion or a pulse of freshwater), in contrast to the long-term recovery from metal contamination. We will compare this recovery to the long-term recovery observed after the 1970’s when the decline in sediment pollutants was the dominating factor.

California↗

USGS1974

A method for estimating magnitude and frequency of floods in South Dakota

A general flood-frequency analysis has provided a method for estimating flood magnitudes and frequencies on South Dakota streams. Related flood data useful in planning and design also are included in the report. Two distinct hydrologic regions are delineated within the State. The divisional boundary for these regions is, in general, the western divide of the James River basin. For each region, the 2-, 5-, 10-, 25-, 50-, and 100-year floods are related to basin and climatic characteristics by regression equations. Indices based on contributing drainage area size, elevation, and mean annual precipitation were found to be the most useful variables in estimation of South Dakota floods. Regional relationships based on these variables can be used to estimate floods of selected frequency at most ungaged sites where peak flows are not significantly affected by regulation or other manmade works. Equations and graphs presented are applicable to drainage basins with areas approximately from 0.1 to 4,000 square miles (0.3 to 10,400 square kilometres) in the Eastern Region and from 0.1 to 9,000 square miles (0.3 to 23,300 square kilometres) in the Western Region. Limitations on use of these equations are given and the accuracy of resulting estimates is discussed. Flood characteristics are tabulated for 130 gaging stations having 10 or more years of record. These frequency data may provide the best estimates of floods at these gaged sites. Also, maximum flood peaks determined at 188 gaging stations and 52 miscellaneous sites are compared with regional flood relationships. Individual relationships are presented for the main-stem portions of selected streams where significant regulation is a factor or where drainage areas exceed the limits of applicability of the regional relationships.

South Dakota↗

USGS2012

Simulation of groundwater and surface-water resources and evaluation of water-management alternatives for the Chamokane Creek basin, Stevens County, Washington

A three-dimensional, transient numerical model of groundwater and surface-water flow was constructed for Chamokane Creek basin to better understand the groundwater-flow system and its relation to surface-water resources. The model described in this report can be used as a tool by water-management agencies and other stakeholders to quantitatively evaluate the effects of potential increases in groundwater pumping on groundwater and surface-water resources in the basin. The Chamokane Creek model was constructed using the U.S. Geological Survey (USGS) integrated model, GSFLOW. GSFLOW was developed to simulate coupled groundwater and surface-water resources. The model uses 1,000-foot grid cells that subdivide the model domain by 102 rows and 106 columns. Six hydrogeologic units in the model are represented using eight model layers. Daily precipitation and temperature were spatially distributed and subsequent groundwater recharge was computed within GSFLOW. Streamflows in Chamokane Creek and its major tributaries are simulated in the model by routing streamflow within a stream network that is coupled to the groundwater-flow system. Groundwater pumpage and surface-water diversions and returns specified in the model were derived from monthly and annual pumpage values previously estimated from another component of this study and new data reported by study partners. The model simulation period is water years 1980-2010 (October 1, 1979, to September 30, 2010), but the model was calibrated to the transient conditions for water years 1999-2010 (October 1, 1998, to September 30, 2010). Calibration was completed by using traditional trial-and-error methods and automated parameter-estimation techniques. The model adequately reproduces the measured time-series groundwater levels and daily streamflows. At well observation points, the mean difference between simulated and measured hydraulic heads is 7 feet with a root-mean-square error divided by the total difference in water levels of 4.7 percent. Simulated streamflow was compared to measured streamflow at the USGS streamflow-gaging station-Chamokane Creek below Falls, near Long Lake (12433200). Annual differences between measured and simulated streamflow for the site ranged from -63 to 22 percent. Calibrated model output includes a 31-year estimate of monthly water budget components for the hydrologic system. Five model applications (scenarios) were completed to obtain a better understanding of the relation between groundwater pumping and surface-water resources. The calibrated transient model was used to evaluate: (1) the connection between the upper- and middle-basin groundwater systems, (2) the effect of surface-water and groundwater uses in the middle basin, (3) the cumulative impacts of claims registry use and permit-exempt wells on Chamokane Creek streamflow, (4) the frequency of regulation due to impacted streamflow, and (5) the levels of domestic and stockwater use that can be regulated. The simulation results indicated that streamflow is affected by existing groundwater pumping in the upper and middle basins. Simulated water-management scenarios show streamflow increased relative to historical conditions as groundwater and surface-water withdrawals decreased.

Washington↗