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Land-margin ecosystem hydrologic data for the coastal Everglades, Florida, water years 1996-2012

Mangrove forests and salt marshes dominate the landscape of the coastal Everglades (Odum and McIvor, 1990). However, the ecological effects from potential sea-level rise and increased water flows from planned freshwater Everglades restoration on these coastal systems are poorly understood. The National Park Service (NPS) proposed the South Florida Global Climate Change Project (SOFL-GCC) in 1990 to evaluate climate change and the effect from rising sea levels on the coastal Everglades, particularly at the marsh/mangrove interface or ecotone (Soukup and others, 1990). A primary objective of SOFL-GCC project was to monitor and synthesize the hydrodynamics of the coastal Everglades from the upstream freshwater marsh to the downstream estuary mangrove. Two related hypotheses were set forward (Nuttle and Cosby, 1993): 1. There exists hydrologic conditions (tide, local rainfall, and upstream water deliveries), which characterize the location of the marsh/mangrove ecotone along the marine and terrestrial hydrologic gradient; and 2. The marsh/mangrove ecotone is sensitive to fluctuations in sea level and freshwater inflow from inland areas. Hydrologic monitoring of the SOFL-GCC network began in 1995 after startup delays from Hurricane Andrew (August 1992) and organizational transfers from the NPS to the National Biological Survey (October 1993) and the merger with the U.S. Geological Survey (USGS) Biological Research Division in 1996 (Smith, 2004). As the SOFL-GCC project progressed, concern by environmental scientists and land managers over how the diversion of water from Everglades National Park would affect the restoration of the greater Everglades ecosystem. Everglades restoration scenarios were based on hydrodynamic models, none of which included the coastal zone (Fennema and others, 1994). Modeling efforts were expanded to include the Everglades coastal zone (Schaffranek and others, 2001) with SOFL-GCC hydrologic data assisting the ecological modeling needs. In 2002, as a response for a more interdisciplinary science approach to understanding the coastal Everglades ecological system, the SOFL-GCC hydrology project was integrated into the “Dynamics of Land-Margin Ecosystems: Historical Change, Hydrology, Vegetation, Sediment, and Climate” study (Smith and others, 2002). Data from the ongoing study has been useful in providing an empirical hydrologic baseline for the greater Everglades ecosystem restoration science and management needs. The hydrology network consisted of 13 hydrologic gaging stations installed in the southwestern coastal region of Everglades National Park along three transects: Shark River (Shark or SH) transect, Lostmans River (Lostmans or LO) transect, and Chatham River (Chatham or CH) transect (fig. 1). There were five paired surface-water/groundwater gaging stations on the Shark transect (SH1, SH2, SH3, SH4, and SH5) and one stage gaging station (BSC) in the Big Sable Creek; four paired surface-water/groundwater gaging stations on the Lostmans transect (LO1, LO2, LO3, and LO4); and three paired surface-water/groundwater gaging stations on the Chatham transect (CH1, CH2, and CH3). Both surface-water and groundwater levels, salinities, and temperatures were monitored at the paired gaging stations. Rainfall was recorded at marsh and open canopy gaging stations. This report details the study introduction, method, and description of data collected, which are accessible through the final instantaneous hydrologic dataset stored in the USGS South Florida Information Access (SOFIA) South Florida Hydrology Database website, http://sofia.usgs.gov/exchange/sfl_hydro_data/location.html#brdlandmargin .

Florida↗

Enhancement of USGS scientific investigations in Texas by using geophysical techniques, 2005-10

Geophysical techniques are an increasingly important tool for scientific investigations, environmental planning, and resource management. During 2005-10 the U.S. Geological Survey Texas Water Science Center greatly expanded its capabilities of using surface and borehole geophysical techniques to gain insights into how groundwater systems work and the occurrence and distribution of certain contaminants. Geophysical techniques provide a relatively quick and inexpensive means to characterize the subsurface hydrology and lithology.

Fact Sheet↗

Aquatics Systems Branch: transdisciplinary research to address water-related environmental problems

The Aquatic Systems Branch at the Fort Collins Science Center is a group of scientists dedicated to advancing interdisciplinary science and providing science support to solve water-related environmental issues. Natural resource managers have an increasing need for scientific information and stakeholders face enormous challenges of increasing and competing demands for water. Our scientists are leaders in ecological flows, riparian ecology, hydroscape ecology, ecosystem management, and contaminant biology. The Aquatic Systems Branch employs and develops state-of-the-science approaches in field investigations, laboratory experiments, remote sensing, simulation and predictive modeling, and decision support tools. We use the aquatic experimental laboratory, the greenhouse, the botanical garden and other advanced facilities to conduct unique research. Our scientists pursue research on the ground, in the rivers, and in the skies, generating and testing hypotheses and collecting quantitative information to support planning and design in natural resource management and aquatic restoration.

Fact Sheet↗

A not so sudden impact—Historical relations between conifers and insects can help predict damage by nonnative insects

The arrival and establishment of nonnative insects in North America is increasingly problematic. International trade has created opportunities to move wood products and nursery stock worldwide, which has increased the risk of insect introduction to regions or countries where they are not native. One group of researchers, the High-impact Insect Invasions Working Group (HIIWG), has developed a predictive model that can be used to estimate the likelihood that a newly arriving nonnative insect may significantly impact North American conifers. The HIIWG examined several traits and factors associated with nonnative insects feeding on conifers (a conifer specialist) already established in North America. Using these data, the HIIWG identified which combination of factors best predicted the risk that a conifer specialist would have a high impact. The researchers then developed a statistical model to predict the probability that a conifer specialist yet to arrive in North America would cause significant damage to conifers if the insect became established. Using three factors, the model calculates the odds of any particular conifer specialist having a high impact on a North American conifer in a range between 1 in 6.5 to 1 in 2,858. This model is a valuable tool to help identify invading insects with the potential to be the most damaging if the insect becomes established in North America. In addition, application of tools like this model can increase positive environmental outcomes for land managers by focusing their efforts on conifer populations that are deemed most vulnerable to extensive mortality

Fact Sheet↗

Trace elements and semi-volatile organic compounds in bed sediments from streams and impoundments at Fort Gordon, Georgia

In May 1998, the U.S. Geological Survey, in cooperation with the Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, investigated the presence and disbursal of trace elements and semi-volatile organic compounds in bed sediments from selected streams and impoundments at the Fort Gordon military installation near Augusta, Georgia. Concentrations of 18 trace elements and total organic carbon, and 66 semi-volatile compounds were determined from analysis of the fine-grained fraction of bed-sediment samples from 29 surface-water deposition locations. Analysis of the bed-sediment data indicates that commercial and industrial land-use areas generally are associated with the highest concentrations of trace elements and semi-volatile organic compounds, and the greatest occurrence and distribution of trace elements and semi-volatile organic compounds in bed sediments at Fort Gordon. Bed sediment collected at sites having drainage areas less than 1.0 square mile and greater than 45 percent commercial and industrial land uses, have the most occurrences and the highest concentrations of trace elements and semi-volatile organic compounds. Sampling sites having less than 2 percent commercial and industrial land uses had the lowest concentrations, regardless of drainage basin size. Relative rankings and evaluation of individual trace element and semi-volatile organic compound concentration data identified two sites that have substantially higher sediment-quality scores than the other sites. This suggests that these sites have the greatest potential risk for adverse effects on aquatic life. The effects of these elevated trace element and semi-volatile organic compound concentrations on aquatic life in these basins may merit further investigation.

Georgia↗

Simple Techniques For Assessing Impacts Of Oil And Gas Operations On Federal Lands - A Field Evaluation At Big South Fork National River And Recreation Area, Scott County, Tennessee

Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands so that sites may be prioritized for further, more formal assessment or remediation. These techniques should allow the field investigator to extend the assessment beyond the surface disturbances documented by simple observation and mapping using field-portable instruments and expendable materials that provide real-time data. The principal contaminants of current concern are hydrocarbons, produced water, and naturally occurring radioactive materials (NORM). Field investigators can examine sites for the impacts of hydrocarbon releases using a photoionization detector (PID) and a soil auger. Volatile organic carbon (VOC) in soil gases in an open auger hole or in the head space of a bagged and gently warmed auger soil sample can be measured by the PID. This allows detection of hydrocarbon movement in the shallow subsurface away from areas of obvious oil-stained soils or oil in pits at a production site. Similarly, a field conductivity meter and chloride titration strips can be used to measure salts in water and soil samples at distances well beyond areas of surface salt scarring. Use of a soil auger allows detection of saline subsoils in areas where salts may be flushed from the surface soil layers. Finally, a microRmeter detects the presence of naturally occurring radioactive materials (NORM) in equipment and soils. NORM often goes undetected at many sites although regulations limiting NORM in equipment and soils are being promulgated in several States and are being considered by the USEPA. With each technique, background sampling should be done for comparison with impacted areas. The authors examined sites in the Big South Fork National River and Recreation Area in November of 1999. A pit at one site at the edge of the flood plain of a small stream had received crude oil releases from a nearby tank. Auger holes down gradient from the pit showed the presence of anomalous concentrations of VOCs at depths of 3 feet for a distance of about 50 feet. PID readings at other sites showed 1) one reclaimed site where hydrocarbon biodegradation was incomplete; 2) one reclaimed site where biodegradation had left no traces of VOCS; and 3) two sites where traces of substantial offsite migration of hydrocarbons occurred. Produced water salts at one site have migrated many 100s of feet downvalley from the area of salt scarring and tree death adjacent to the pits. Naturally occurring radioactivity (NORM) at most sites was at background. One site showed anomalous radioactivity related to NORM in a small brine pit. Some of this NORM has moved downslope from the outlet pipe to the pit.

Open-File Report↗

Simple Techniques For Assessing Impacts Of Oil And Gas Operations On Public Lands: A Field Evaluation Of A Photoionization Detector (PID) At A Condensate Release Site, Padre Island National Seashore, Texas

Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands, so that sites may be prioritized for remediation or for further, more formal assessment. Field-portable instruments provide real-time data and allow the field investigator to extend an assessment beyond simply locating and mapping obvious disturbances. Field investigators can examine sites for the presence of hydrocarbons in the subsurface using a soil auger and a photoionization detector (PID). The PID measures volatile organic compounds (VOC) in soil gases. This allows detection of hydrocarbons in the shallow subsurface near areas of obvious oil-stained soils, oil in pits, or dead vegetation. Remnants of a condensate release occur in sandy soils at a production site on the Padre Island National Seashore in south Texas. Dead vegetation had been observed by National Park Service personnel in the release area several years prior to our visit. The site is located several miles south of the Malaquite Beach Campground. In early 2001, we sampled soil gases for VOCs in the area believed to have received the condensate. Our purpose in this investigation was: 1) to establish what sampling techniques might be effective in sandy soils with a shallow water and contrast them with techniques used in an earlier study; and 2) delineate the probable area of condensate release. Our field results show that sealing the auger hole with a clear, rigid plastic tube capped at the top end and sampling the soil gas through a small hole in the cap increases the soil VOC gas signature, compared to sampling soil gases in the bottom of an open hole. This sealed-tube sampling method increases the contrast between the VOC levels within a contaminated area and adjacent background areas. The tube allows the PID air pump to draw soil gas from the volume of soil surrounding the open hole below the tube in a zone less influenced by atmospheric air. In an open hole, the VOC readings seem to be strongly dependent on the degree of diffusion and advection of soil gas VOCs into the open hole from the surrounding soil, a process that may vary with soil and wind conditions. Making measurements with the sealed hole does take some additional time (4-7 minutes after the hole is augered) compared to the open-hole technique (1-2 minutes). We used the rigid-plastic tube technique to survey for soil gas VOCs across the entire site, less than ? acre. Condensate has impacted at least 0.28 acres. The impacted area may extend northwest of the surveyed area.

Open-File Report↗

Data on surface-water, streambed-interstitial water, and bed-sediment quality for selected locations in the small arms impact area of central Fort Gordon, Georgia, September 4-6, 2001

In September 2001, the U.S. Geological Survey, in cooperation with the Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon (U.S. Department of the Army), conducted a chemical assessment of surface water, streambed-interstitial water, and bed sediments within the small arms impact area of Fort Gordon Military Installation. The study was conducted in support of the development of an Integrated Natural Resources Management Plan (INRMP) for Fort Gordon, Georgia. An effective INRMP ensures that natural resources conservation measures and U.S. Army activities on the military base are integrated and consistent with Federal requirements to manage military installations on an ecosystem basis. Filtered water samples were collected from five sites along South Prong Creek and three sites along Marcum Branch Creek for chemical analyses of major ions, nutrients, and selected trace elements. On-site measurements of pH, temperature, specific conductance, and dissolved oxygen were made at the eight sites. Filtered water collected showed varying concentrations in both surface- and streambed-interstitial water. Bed-sediment samples collected from South Prong Creek contain elevated levels of arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, iron, lead, manganese, nickel, selenium, vanadium, and total organic carbon relative to previous concentrations (McConnell and others, 2000). Bed-sediment samples collected from Marcum Branch Creek contain elevated levels of beryllium, copper, lead, manganese, mercury, selenium, and total organic carbon relative to previous concentrations (McConnell and others, 2000).

Georgia↗

Selected Streamflow Statistics for Streamgaging Stationsin Northeastern Maryland, 2006

Streamflow statistics were calculated for 47 U.S. Geological Survey (USGS) streamgaging stations in northeastern Maryland, in cooperation with (1) the University of Maryland, Baltimore County, Center for Urban Environmental Research and Education; (2) the Baltimore City Department of Public Works; and (3) the Baltimore County Department of Environmental Protection and Resource Management. The statistics include the mean, minimum, maximum, and standard deviation of the daily mean discharges for the periods of record at the stations, as well as flow-duration and low-flow frequency statistics. The flow-duration statistics include the 1-, 2-, 5-, 10-, 15-, 20-, 25-, 30-, 40-, 50-, 60-, 70-, 75-, 80-, 85-, 90-, 95-, 98-, and 99-percent duration discharges. The low-flow frequency statistics include the average discharges for 1, 7, 14, and 30 days that recur, on average, once in 1.01, 2, 5, 10, 20, 50, and 100 years. The statistics were computed only for the 25 stations with periods of record of 10 years or more. The statistics were computed from records available through September 30, 2004 using standard methods and computer software developed by the USGS. A comparison between low-flow frequency statistics computed for this study and for a previous study that used data available through September 30, 1989 was done for seven stations. The comparison indicated that, for the 7-day mean low flow, the newer values were 19.8 and 15.3 percent lower for the 20- and 10-year recurrence intervals, respectively, and 2.1 percent higher for the 2-year recurrence interval, than the older values. For the 14-day mean low flow, the newer 20- and 10-year values were 25.2 and 15.5 percent lower, respectively, and the 2-year value was 2.9 percent higher than the older values. For the 30-day mean low flow, the newer 20-, 10-, and 2-year values were 10.8, 7.9, and 0.8 percent lower, respectively, than the older values. The newer values are generally lower than the older ones most likely because two major droughts have occurred since the older study was completed.

Open-File Report↗

Quantity and quality of stormwater collected from selected stormwater outfalls at industrial sites, Fort Gordon, Georgia, 2011

An assessment of the quantity and quality of stormwater runoff associated with industrial activities at Fort Gordon was conducted from January through December 2011. The assessment was provided to satisfy the requirements from a general permit that authorizes the discharge of stormwater under the National Pollutant Discharge Elimination System from a site associated with industrial activities. The stormwater quantity refers to the runoff discharge at the point and time of the runoff sampling. The study was conducted by the U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon. The initial scope of this study was to sample stormwater runoff from five stations at four industrial sites (two landfills and two heating and cooling sites). As a consequence of inadequate hydrologic conditions during 2011, no samples were collected at the two landfills; however, three samples were collected from the heating and cooling sites. The assessment included the collection of physical properties, such as water temperature, specific conductance, dissolved oxygen, and pH; the detection of suspended materials (total suspended solids, total fixed solids, total volatile solids), nutrients and organic compounds, and major and trace inorganic compounds (metals); and the detection of volatile and semivolatile organic compounds. Nutrients and organic compounds, major and trace inorganic compounds, and volatile and semivolatile organic compounds were detected above the laboratory reporting levels in all samples collected from the three stations. The detection of volatile and semivolatile organic compounds included anthracene, benzo[ a ]anthracene, benzo[ a ]pyrene, benzo[ ghi ]perylene, cis ,1, 2-dichloroethene, dimethyl phthalate, fluoranthene, naphthalene, pyrene, acenaphthylene (station SWR11-3), and di-n-butyl phthalate (station SWR11-4).

Georgia↗

Summary of data from onsite and laboratory analyses of surface water and marsh porewater from South Florida Water Management District Water Conservation Areas, the Everglades, South Florida, March 1995

This report presents results of chemical analysis for samples collected during March, 1995, as part of a study to quantify the interaction of aquatic organic material (referred to here as dissolved organic carbon with dissolved metal ions). The work was done in conjunction with the South Florida Water Management District, the U.S. Environmental Protection Agency, the U.S. Geological Survey South Florida Ecosystems Initiative, and the South Florida National Water Quality Assessment Study Unit. Samples were collected from surface canals and from marsh sites. Results are based on onsite and laboratory measurements for 27 samples collected at 10 locations. The data file contains sample description, dissolved organic carbon concentration and specific ultraviolet absorbance, and additional analytical data for samples collected at several sites in the Water Conservation Areas, the Everglades, south Florida.

Florida↗

Assessment of soil-gas contamination at building 310 underground storage tank area, Fort Gordon, Georgia, 2010-2011

Soil gas was assessed for contaminants in the building 310 underground storage tank area adjacent to the Dwight D. Eisenhower Army Medical Center at Ft. Gordon, Georgia, from October 2010 to September 2011. The assessment, which also included the detection of organic compounds in soil gas, provides environmental contamination data to Fort Gordon personnel pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. The study was conducted by the U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon. Soil-gas samplers were deployed below land surface at 37 locations in the building 310 underground storage tank area. Soil-gas samplers were deployed in a grid pattern near the storage tank area as well as downslope of the tank area in the direction of groundwater flow toward an unnamed tributary to Butler Creek. Total petroleum hydrocarbons were detected in 35 of the 37 soil-gas samplers at levels above the method detection level, and the combined mass of benzene, toluene, ethylbenzene, and total xylenes were detected above their detection levels in 8 of the 37 samplers. In addition, the combined masses of undecane, tridecane, and pentadecane were detected at or above their method detection levels in 9 of the 37 samplers. Other volatile organic compounds detected above their respective method detection levels were chloroform, 1,2,4-trimethylbenzene, and perchloroethylene. In addition, naphthalene, 2-methyl naphthalene, and 1,2,4-trimethylbenzene were detected below the method detection levels, but above the nondetection level.

Georgia↗

Quantity and quality of stormwater collected from selected stormwater outfalls at industrial sites, Fort Gordon, Georgia, 2012

An assessment of the quantity and quality of stormwater runoff associated with industrial activities at Fort Gordon was conducted from January through August 2012. The assessment was provided to satisfy the requirements from a general permit that authorizes the discharge of stormwater under the National Pollutant Discharge Elimination System from a site associated with industrial activities. The stormwater quantity refers to the runoff discharge at the point and time of the runoff sampling. The study was conducted by the U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon. Stormwater runoff samples were collected from five stations at four industrial sites, including two landfills (SWR11–1 and SWR11–2) and three heating and cooling sites, SWR11–3, SWR11–4, and SWR11–5. The assessment included the collection of physical properties, such as dissolved oxygen and pH; the detection of suspended materials (total suspended solids, total fixed solids, and total volatile solids), nutrients and organic compounds, and major and trace inorganic compounds (metals); and for the three heating and cooling sites, the detection of volatile and semivolatile organic compounds. Landfill site SWR11–2 had the greatest total suspended solid concentration (214 milligrams per liter) of all sites and exceeded the daily maximum effluent limit for landfills. Heating and cooling site SWR11–3 had the greatest total suspended solid concentration (169 milligrams per liter), total fixed solids (101 milligrams per liter), and total volatile solids (68 milligrams per liter) when compared to the three heating and cooling sites. Total nitrogen and phosphorus concentrations were 1.02 and 0.09, and 1.74 and 0.21 milligrams per liter, respectively, at landfill sites SWR11–1 and SWR11–2. At heating and cooling sites, total nitrogen and phosphorus concentrations ranged from 0.53 to 1.08 milligrams per liter and 0.07 to 0.1 milligram per liter, respectively, with the highest concentrations measured at site SWR11–3. Additionally, oil and grease concentrations at all sites were compared to applicable benchmark standards; no sample concentrations exceeded these standards. The estimated dissolved concentrations of cadmium, lead, nickel, zinc, mercury, and silver, and the total recoverable concentrations of arsenic and selenium were compared to applicable benchmark levels and to acute and chronic effect aquatic-life criteria for further screening purposes. The estimated dissolved zinc concentration (105 micrograms per liter) at site SWR11–3 was the only constituent to exceed a benchmark standard (40 micrograms per liter). Estimated dissolved zinc concentrations at sites SWR11–4 and SWR11–5 exceeded acute and chronic effect aquatic-life criteria. Estimated dissolved concentrations of lead exceeded the chronic effect aquatic-life criteria at all sites and exceeded the acute effect criteria at site SWR11–3. Acute and chronic effect aquatic-life criteria for dissolved cadmium were exceeded at site SWR11–3. Samples from sites SWR11–3, SWR11–4, and SWR11–5 were analyzed for 83 volatile and semivolatile organic compounds. Eight polycyclic aromatic hydrocarbon compounds, benzo[ a ]pyrene, benzo[ b ]fluoranthene, benzo[ ghi ]perylene, benzo[ k ]fluoranthene, chrysene, indeno[1,2,3- cd ]pyrene, phenanthrene, and pyrene, were detected at all three sites. Of the 86 volatile and semivolatile organic compounds that were analyzed in stormwater samples from heating and cooling sites, 15 (18 percent) were detected at site SWR11–3, 12 (14 percent) were detected at site SWR11–4, and 17 (20 percent) were detected at site SWR11–5.

Georgia↗

Serious games experiment toward agent-based simulation

We evaluate the potential for serious games to be used as a scientifically based decision-support product that supports the United States Geological Survey’s (USGS) mission--to provide integrated, unbiased scientific information that can make a substantial contribution to societal well-being for a wide variety of complex environmental challenges. Serious or pedagogical games are an engaging way to educate decisionmakers and stakeholders about environmental challenges that are usefully informed by natural and social scientific information and knowledge and can be designed to promote interactive learning and exploration in the face of large uncertainties, divergent values, and complex situations. We developed two serious games that use challenging environmental-planning issues to demonstrate and investigate the potential contributions of serious games to inform regional-planning decisions. Delta Skelta is a game emulating long-term integrated environmental planning in the Sacramento-San Joaquin Delta, California, that incorporates natural hazards (flooding and earthquakes) and consequences for California water supplies amidst conflicting water interests. Age of Ecology is a game that simulates interactions between economic and ecologic processes, as well as natural hazards while implementing agent-based modeling. The content of these games spans the USGS science mission areas related to water, ecosystems, natural hazards, land use, and climate change. We describe the games, reflect on design and informational aspects, and comment on their potential usefulness. During the process of developing these games, we identified various design trade-offs involving factual information, strategic thinking, game-winning criteria, elements of fun, number and type of players, time horizon, and uncertainty. We evaluate the two games in terms of accomplishments and limitations. Overall, we demonstrated the potential for these games to usefully represent scientific information within challenging environmental and ecosystem-management contexts and to provide an interactive way of learning about the complexity of interactions between people and natural systems. Further progress on the use of pedagogical games to fulfill the USGS mission will require collaboration among scientists, game developers, educators, and stakeholders. We conclude that as the USGS positions itself to communicate and convey the results of multiple science strategies, including natural-resource security and sustainability, pedagogical game development and agent-based modeling offer a means to (1) establish interdisciplinary and collaborative teams with a focused integrated outcome; (2) contribute to the modeling of interaction, feedback, and adaptation of ecosystems; and (3) enable social learning through a broadly appealing and increasingly sophisticated medium.

Open-File Report↗

Current meter observations within lower Cook Inlet, Alaska, 1978-1979 from the R/V Sea Sounder, Pacific-Arctic Branch, U.S. Geological Survey

The U.S. Geological Survey under contract to the U.S. Bureau of Land Management conducted geo-environmental hazard studies within lower Cook Inlet, Alaska from 1975 through 1979 (Bouma and Hampton, 1976; Bouma and others, 1977 a,b, 1978 ; Hampton and Bouma 1979). As part of this effort the U.S. Geological Survey research vessel, R/V SEA SOUNDER, conducted two cruises in 1978 and one cruise in 1979 (Table 1). A number of stations were occupied for various periods of time (Fig. 1) during which tidal current speed and direction data was recorded. Some 1978 data was obtained concurrently with bottom boundary layer experiments conducted with a large instrumented tripod system referred to as GEOPROBE (Cacchione and Drake, 1979).

Alaska↗

Hydrologic and geochemical controls on pesticide and nutrient transport to two streams on the Delmarva Peninsula

Pesticides and nutrients move from application areas through ground water and surface runoff to streams on the Delmarva Peninsula. The relative importance of different transport media to the movement of these compounds in different watersheds is related to locally variable hydrologic and geochemical conditions among areas of regionally similar land use, geology, and soils. Consideration of such local variability is important to land-management efforts or future environmental investigations on the Peninsula. Chemical analyses of samples collected over a multiyear period from two streams on the Delmarva Peninsula were analyzed along with similar available analyses of ground water to document the occurrence of pesticides and nutrients, and illustrate important processes controlling their movement through watersheds to streams. The upper Pocomoke River and Chesterville Branch drain predominantly agricultural watersheds typical of the Delmarva Peninsula. Chesterville Branch drains a watershed of moderate relief, good drainage, and a permeable surficial aquifer that ranges in thickness from about 15 to 25 meters. The upper Pocomoke River Watershed, however, is extremely flat with poorly drained soils and abundant artificial drainage. Influences on the chemistry of water in each stream were determined from seasonal patterns in the concentrations of selected constituents from 1996 through 2001, and relations with streamflow. Nutrients and pesticides are detectable throughout the year in the upper Pocomoke River and Chesterville Branch. Water in both streams is typically dilute, slightly acidic, and well oxygenated, and nitrate and phosphorus concentrations generally exceed estimated natural levels. Pesticide concentrations are generally low, although concentrations of selected metabolites commonly exceed 1 microgram per liter, particularly in Chesterville Branch. Nitrate and metabolites of pesticide compounds are apparently transported to Chesterville Branch preferentially through ground water in the surficial aquifer, although selected pesticide parent compounds and less soluble nutrients move primarily in surface runoff. Conversely, the relative proportion of discharge from surficial and partially confined aquifers is the most important factor controlling the chemistry of water in the upper Pocomoke River. Surface runoff in the larger and predominantly flat upper Pocomoke River Watershed is apparently limited to particularly significant precipitation events. Transport of pesticides in surface runoff becomes important in both watersheds during such events. Instantaneous loads of pesticides in streams typically stabilize or continue to increase with increasing flow even after runoff begins, although in-stream concentrations may decrease due to dilution.

Scientific Investigations Report↗