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Northwest Forest Plan — The first 25 years (1994–2018): Watershed condition status and trends

This report describes status and trends in watershed condition across the Northwest Forest Plan (NWFP) area over the first 25 years since its inception in 1994. The program charged with this task is the Aquatic and Riparian Effectiveness Monitoring Program (AREMP), which has assembled information from field data collection, spatial datasets, and a host of landscape models to evaluate the status and trends in aquatic resources in streams and watersheds. Field data included hydrologic measurements (stream wetted widths and temperatures), geomorphic responses (instream wood and sediment), and biological responses (macroinvertebrates and aquatic organism passage). Novel statistical models were used to estimate trends in these measured responses. A suite of complementary modeled results was also employed to describe hydrometeorological drivers (e.g., drought indices and stream discharge), forest cover (upslope and riparian vegetation), and geomorphic conditions (e.g., road-related estimates of chronic and shallow landslide sediment delivery risk). Collectively, information on these responses allowed us to rigorously evaluate instream responses and hypothesize watershed drivers of those responses across the NWFP area and over time. The majority of responses we observed indicated widespread and incremental improvements from active management of forests, forest roads, and road-stream crossings as envisioned by the aquatic conservation strategy of the NWFP. Additionally, many of the responses we observed were consistent with those expected under the influences of changing climates in the Pacific Northwest. Ultimately, the long-term, broad-scale information provided by AREMP is a critical foundation for evaluating the effectiveness of federal land management and the effects of changing climates on water resources that sustain the Pacific Northwest’s human and natural landscapes.

California, Oregon, Washington↗

Managing ecotourism visitation in protected areas

Ecotourism management seeks to integrate and balance several potentially conflicting objectives: protection of natural and cultural resources, provision of recreation opportunities and generation of economic benefits. In the absence of effective planning and management, ecotourism can lead to significant negative impacts on vegetation, soil, water, wildlife, historic resources, cultures, and visitor experiences. This chapter reviews visitor-related natural resource and experience impacts associated with ecotourism within protected areas. The influence of factors that control the nature and extent of impacts are also reviewed, including type and amount of use, the variable resistance and resilience of environmental attributes such as vegetation and soil types, and the role of management in shaping visitation, resources and facilities to support visitation while minimizing associated impacts. Implications for managing the effects of protected area visitation are highlighted, including carrying capacity decision frameworks and selecting management strategies and tactics.

Book chapter↗

Agricultural irrigated land-use inventory for Osceola County, Florida, October 2013-April 2014

A detailed inventory of irrigated crop acreage is not available at the level of resolution needed to increase the accuracy of current water-use estimates or to project future water demands in many Florida counties. This report provides a detailed digital map and summary of irrigated areas within Osceola County for the agricultural growing period October 2013–April 2014. The irrigated areas were first delineated using land-use data and satellite imagery and then field verified between February and April 2014. Selected attribute data were collected for the irrigated areas, including crop type, primary water source, and type of irrigation system. Results indicate that an estimated 27,450 acres were irrigated during the study period. This includes 4,370 acres of vegetables, 10,970 acres of orchard crops, 1,620 acres of field crops, and 10,490 acres of ornamentals and grasses. Specifically, irrigated acreage included citrus (10,860 acres), sod (5,640 acres), pasture (4,580 acres), and potatoes (3,320 acres). Overall, groundwater was used to irrigate 18,350 acres (67 percent of the total acreage), and surface water was used to irrigate the remaining 9,100 acres (33 percent). Microirrigation systems accounted for 45 percent of the total acreage irrigated, flood systems 30 percent, and sprinkler systems the remaining 25 percent. An accurate, detailed, spatially referenced, and field-verified inventory of irrigated crop acreage can be used to assist resource managers making current and future county-level water-use estimates in Osceola County.

Florida↗

Hydrogeologic characteristics of the St. Croix River basin, Minnesota and Wisconsin: Implications for the susceptibility of ground water to potential contamination

Population growth in the St. Croix River Basin in Minnesota and Wisconsin has intensified concerns of county resource managers and the National Park Service, which is charged with protecting the St. Croix National Scenic Riverway, about the potential for ground-water contamination in the basin. This report describes a previously developed method that was adapted to illustrate potential ground-water-contamination susceptibility in the St. Croix River Basin. The report also gives an estimate of ground-water-residence time and surface-water/ground-water interaction as related to natural attenuation and movement of contaminants in five tributary basins. A ground-water-contamination-susceptibility map was adapted from a state-wide map of Wisconsin to the St. Croix River Basin by use of well-driller construction records and regional maps of aquifer properties in Minnesota and Wisconsin. Measures of various subsurface properties were combined to generate a spatial index of susceptibility. The subjective index method developed for the State of Wisconsin by Schmidt (1987) 1 was not derived from analyses of water-quality data or physical processes. Nonetheless, it was adapted for this report to furnish a seamless map across state boundaries that would be familiar to many resource managers. Following this method, areas most susceptible to contamination appear to have coarse-grained sediments (sands or gravels) and shallow water tables or are underlain by carbonate-bedrock aquifers. The least susceptible areas appear to have fine-grained sediments and deep water tables. If an aquifer becomes contaminated, the ground-water-residence time can affect potential natural attenuation along the ground-water-flow path. Mean basin ground-water-residence times were computed for the Apple, Kettle, Kinnickinnic, Snake and Sunrise River Basins, which are tributary basins to the St. Croix Basin, by use of average aquifer properties of saturated thickness, porosity, and recharge rates. The Apple River Basin had the shortest mean ground-water-residence times (20–120 years), owing largely to the moderate saturated thickness and high recharge rate in the basin. The Kinnickinnic and Sunrise River Basins had the longest mean residence times (60–350 and 70–390 years, respectively) chiefly because of the relatively large saturated thickness of the basins. Owing to limitations of the residence-time calculations, actual ground-water-residence times will vary around the mean values within each basin and may range from days or weeks in karst carbonate aquifers to millennia in deep confined sandstone aquifers. Areas of relatively short residence time (less than the median residence time in each basin) were identified by use of ground-water-flow models for each of the five tributary basins. Results of simulations show that these areas, in which contaminants may have relatively less time for natural attenuation along the short flow paths, generally occur near streams and rivers where ground water discharges to the surface. Finally, the ground-water-flow models were used to simulate ground-water/surface-water interaction in the five tributary basins. Results of simulations show that some lakes and reservoirs leak surface water into the ground-water-flow system on their downgradient side, where the surface-water outflow has been restricted by a dam or a naturally constricted outlet. These locations are noteworthy because contaminated surface waters could potentially enter the ground-water-flow system at these locations.

Minnesota, Wisconsin↗

Construction of a groundwater-flow model for the Big Sioux Aquifer using airborne electromagnetic methods, Sioux Falls, South Dakota

The city of Sioux Falls is the fastest growing community in South Dakota. In response to this continued growth and planning for future development, Sioux Falls requires a sustainable supply of municipal water. Planning and managing sustainable groundwater supplies requires a thorough understanding of local groundwater resources. The Big Sioux aquifer consists of glacial outwash sands and gravels and is hydraulically connected to the Big Sioux River, which provided about 90 percent of the city’s source-water production in 2015. Managing sustainable groundwater supplies also requires an understanding of groundwater availability. An effective mechanism to inform water management decisions is the development and utilization of a groundwater-flow model. A groundwater-flow model provides a quantitative framework for synthesizing field information and conceptualizing hydrogeologic processes. These groundwater-flow models can support decision making processes by mapping and characterizing the aquifer. Accordingly, the city of Sioux Falls partnered with the U.S. Geological Survey to construct a groundwater-flow model. Model inputs will include data from advanced geophysical techniques, specifically airborne electromagnetic methods.

South Dakota↗

Streamflow as a stressor: Disentangling hydrology and water quality impacts to characterize flow-ecology relationships for two stream assemblages across two southeastern landscapes

Disassociating the independent effects of flow and water quality on the ecology of flowing waters is an overarching goal in water resource science needed to improve the efficacy of watershed management. However, the interrelatedness of these gradients and their subsequent alteration due to land use change has constrained progress made on this front. The objective of this study was to use benthic macroinvertebrate and fish assemblage data to characterize flow-ecology relationships that were unchanged by water quality impacts across two southeastern landscapes in the USA to help detect ecological change driven by flow alteration. General linear latent models were used to identify taxa that were responsive to high or low flow metrics and water quality gradients. Bayesian hierarchical generalized additive models were then developed using these indicator taxa and three biological metrics to identify flow-specific relationships that were unaffected by water quality impacts. Three low flow-specific relationships were identified, illustrating how potential agricultural or urban impacts to hydrology reduced stream biological health. Importantly, flow-ecology relationships developed using indicator taxa in this study effectively captured hydrology-specific impacts while biological metrics typical of state monitoring and assessment programs did not. Therefore, developing flow-specific biological metrics is a critical step when developing management strategies targeting flow alteration. Implementing standardized frameworks such as the one characterized here can limit contradictory findings and improve streamflow enhancement and restoration project efficacy. These low flow-specific relationships will enhance managers' capacity to develop environmental flow standards, monitor their success, and better understand urban and agricultural impacts on stream assemblages.

Alabama↗

The 3D Elevation Program—Supporting Louisiana's economy

Introduction Recent and ongoing collections of high-resolution elevation data in Louisiana are providing information that supports improved critical public safety modeling and enables the State to strengthen its efforts to fight the effects of land subsidence and sea-level rise. The availability of current and accurate three-dimensional (3D) elevation data supports numerous business activities, including flood risk management, infrastructure and construction management, coastal zone management, wildlife and habitat management, recreation, agriculture and precision farming, urban and regional planning, water supply and quality assessment, and natural resources conservation. Critical applications that meet the State’s management needs depend on light detection and ranging (lidar) data that provide a highly detailed 3D model of the Earth’s surface and aboveground features. The 3D Elevation Program (3DEP) is managed by the U.S. Geological Survey (USGS) in partnership with Federal, State, Tribal, U.S. territorial, and local agencies to acquire consistent lidar coverage at quality level 2 or better to meet the many needs of the Nation and Louisiana. The status of available and in-progress 3DEP baseline lidar data in Louisiana is shown in figure 1. 3DEP baseline lidar data include quality level 2 or better, 1-meter or better digital elevation models, and lidar point clouds, and must meet the Lidar Base Specification version 1.2 ( https://www.usgs.gov/3dep/lidarspec ) or newer requirements. The National Enhanced Elevation Assessment identified user requirements and conservatively estimated that availability of lidar data would result in at least $6.96 million in new benefits annually to the State. The top 10 Louisiana business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown in table 2.

Louisiana↗

Processes influencing the transport and fate of contaminated sediments in the coastal ocean– Boston Harbor and Massachusetts Bay

Most of the major urban centers of the United States including Boston, New York, Washington, Chicago, New Orleans, Miami, Los Angeles, San Francisco, and Seattle—are on a coast (fig. 1.1). All of these cities discharge treated sewage effluent into adjacent waters. In 2000, 74 percent of the U.S. population lived within 200 kilometers (km) of the coast. Between 1980 and 2002, the population density in coastal communities increased approximately 4.5 times faster than in noncoastal areas of the U.S. (Perkins, 2004). More people generate larger volumes of wastes, increase the demands on wastewater treatment, expand the area of impervious land surfaces, and use more vehicles that contribute contaminants to street runoff. According to the National Coastal Condition Report II (U.S. Environmental Protection Agency, 2005a), on the basis of coastal habitat, water and sediment quality, benthic index, and fish tissue, the overall national coastal condition is only poor to fair and the overall coastal condition in the highly populated Northeast is poor. Scientific information helps managers to prioritize and regulate coastal-ocean uses that include recreation, commercial fishing, transportation, waste disposal, and critical habitat for marine organisms. These uses are often in conflict with each other and with environmental concerns. Developing a strategy for managing competing uses while maintaining sustainability of coastal resources requires scientific understanding of how the coastal ocean system behaves and how it responds to anthropogenic influences. This report provides a summary of a multidisciplinary research program designed to improve our understanding of the transport and fate of contaminants in Massachusetts coastal waters. Massachusetts Bay and Boston Harbor have been a focus of U.S. Geological Survey (USGS) research because they provide a diverse geographic setting for developing a scientific understanding of the geology, geochemistry, and oceanography of coastal systems in general. Scientific data from this region can also be used to inform decisions about important economic, environmental, and political issues. From the economic viewpoint, the annual value of tourism and shipping in Massachusetts and Cape Cod Bays is about $1.5 billion and $1.9 billion, respectively. Commercial and recreational fishing generates about $240 million per year in the same region (U.S. Environmental Protection Agency, 2005b). The environmental issue is the 300-year history of waste discharge from the Boston metropolitan area into the harbor. This history is punctuated by cycles of environmental degradation, public outcry, and improvements in the sewage treatment system. With each improvement, however, the continuous growth of population in greater Boston (fig. 1.2) and the resulting increase in the volume of waste exceeded the capacity of the treatment system, thereby setting the stage for a new contamination crisis. By the 1980s, the levels of contaminants in sediments of Boston Harbor were among the highest in the nation (National Oceanic and Atmospheric Administration, 1987). Fish were diseased, shellfish beds were closed, and swimming beaches were unsafe after heavy rains; in general, water quality and aesthetics were below acceptable standards. Legal and political issues have always been part of Boston Harbor’s history. The environmental conditions in the 1980s were highlighted in a 1983 legal suit brought by the city of Quincy against the Metropolitan District Commission (MDC, the state agency responsible for sewage treatment) and heads of three state agencies for discharging untreated or poorly treated sewage into the harbor (Dolin, 2004). The suit never went to trial, but through the actions of a Massachusetts Superior Court, the issue of Boston Harbor contamination remained on the political and public agenda. The judge called the harbor “unsafe, unsanitary, indecent, in violation of the law (Clean Water Act), and a danger to the health and welfare of the people” (Forman, 1984). To force the state legislature to implement a plan to improve harbor conditions, the judge threatened to place the MDC in receivership and curtail new sewage hookups for industry. Under intense lobbying by business, the legislature created the Massachusetts Water Resources Authority (MWRA) in December 1984. The independent MWRA was established to manage Boston’s waste treatment system and was given the authority to float bonds to pay for major improvements in the treatment system. In 1985, a Federal court began hearings on a suit brought by the Conservation Law Foundation, the Environmental Protection Agency (USEPA), and towns of Quincy and Winthrop against the MDC and MWRA (as heir to responsibilities of the MDC) for years of violation of the Clean Water Act. The judge ruled against the defendants and required all the parties to submit a construction plan and schedule for a new sewage treatment system. From these submissions, he developed a schedule for treatment system upgrades that would give the “citizens of this commonwealth a public assurance that Boston Harbor will be cleaned up within a defined period of time” (Dolin, 2004). The MWRA’s Boston Harbor cleanup program (Levy and Connor, 1992) has transformed the Boston sewage system. Key improvements were to (1) reduce contaminants at the industrial source; (2) remediate leaks in the sewage-collection system; (3) eliminate sewage sludge discharge to the harbor; (4) upgrade sewage treatment from primary to secondary; (5) construct a new ocean outfall 15.2 km offshore in Massachusetts Bay for discharge of treated effluent (fig. 1.3); and (6) implement improvements in the combined-sewer-overflow system. As part of the harbor cleanup program, the MWRA developed a comprehensive monitoring program (summarized in MWRA, 2004) to assess changes in the harbor and bays that specifically related to the new sewage system. Additional information about conditions and processes in the coastal system on a regional scale and over a long time period was and continues to be important in predicting and interpreting local change. Implementation of the MWRA’s program and the mission of the USGS to understand the geology of the nation’s offshore waters provided an opportunity to conduct a cooperative multidisciplinary research program. This USGS program addresses basic scientific questions as well as concerns raised by management regarding the design, implementation, and assessment of the new sewage treatment system. Already active in Boston Harbor during the late 1970s, the USGS expanded research into Massachusetts Bay with a multidisciplinary program in 1989.

Massachusetts↗

Benthic oxygen demand in three former salt ponds adjacent to south San Francisco Bay, California

Sampling trips were coordinated in the second half of 2008 to examine the interstitial water in the sediment and the overlying bottom waters of three shallow (average depth <1 meter) ponds adjacent to the southern reach of San Francisco Bay (herein referred to as South Bay), which were previously used in commercial salt production. In recent years, the ponds were modified for wetland restoration and management as part of the South Bay Salt Pond Restoration Project. A pore-water profiler, modified for dissolved-oxygen sampling, was used to obtain the first centimeter-scale estimates of the vertical concentration gradients for diffusive-flux determinations. This study, a collaboration between scientists from two disciplines within the U.S. Geological Survey (Water Resources and Biological Resources), provides information necessary for developing and refining pond-management strategies and supports efforts to monitor changes in fish and wildlife assemblages associated with the habitat-restoration program. Between August 27 and September 30, 2008, pore-water profilers were successfully deployed in the South Bay salt ponds A16, A14, and A3W (fig. 1; fig. 2; table1), measuring the concentration gradient of dissolved oxygen near the sediment-water interface. In each pond, profilers were deployed in triplicate at two sites: a shallow site (< 1 meter) and a deep site (> 2 meters). The water column at all deployment sites was monitored with dataloggers for ancillary water-quality parameters (including dissolved oxygen, salinity, specific conductance, temperature, and pH) to facilitate the interpretation of benthic-flux results. Calculated diffusive benthic flux of dissolved (0.2-micron filtered) oxygen was consistently negative (that is, drawn from the water column into the sediment) and ranged between -0.5 x 10-6 and -37 x 10-6 micromoles per square centimeter per second (site averages depicted in table 2). Assuming pond areas of 1.0, 1.4, and 2.3 square kilometers for ponds A16, A14, and A3W, respectively, this converts to an oxygen mass flux into the ponds' sediment ranging from -1 to -72 kilograms per day. Diffusive oxygen flux into the benthos (listed as negative) was lowest in pond A14 (-0.5 x 10-6 to -1.8 x 10-6 micromoles per square centimeter per second) compared with diffusive flux estimates for ponds A16 and A3W (site averages -26 x 10-6 to -35 x 10-6 and -34 x 10-6 to -37 x 10-6 micromoles per square centimeter per second, respectively). These initial diffusive-flux estimates are of the order of magnitude of those measured in the South Bay using core-incubation experiments (Topping and others, 2004), which include bioturbation and bioirrigation effects. Estimates of benthic oxygen demand reported herein, based on molecular diffusion, serve as conservative estimates of benthic flux because solute transport across the sediment-water interface can be enhanced by multidisciplinary processes including bioturbation, bioirrigation, ground-water advection, and wind resuspension (Kuwabara and others, 2009).

California↗

Acid rain in Shenandoah National Park, Virginia

Visitors to Shenandoah National Park (SNP) enjoy the animal and plant life and the scenery but may not realize how vulnerable these features are to various threats, such as invasion of exotic plants and insects, improper use of park resources by humans, and air and water pollution. The National Park Service strives to protect natural resources from such threats to ensure that the resources will be available for enjoyment now and in the future. Because SNP has limited influence over the air pollution that envelops the region, acidic deposition--commonly known as acid rain--is one of the more challenging threats facing park managers. With the help of U.S. Geological Survey (USGS) scientists, park managers can understand how acid rain interacts with ground- and surface-water resources, which enables them to explain why reductions in air pollution can help preserve park resources. Such understanding also provides essential insight into ecosystem processes, as managers strive to unravel and resolve other environmental problems that are interrelated to acid rain.

Virginia↗

Simulation of streamflow in the Pleasant, Narraguagus, Sheepscot, and Royal Rivers, Maine, using watershed models

The U.S. Geological Survey (USGS) began a study in 2008 to investigate anticipated changes in summer streamflows and stream temperatures in four coastal Maine river basins and the potential effects of those changes on populations of endangered Atlantic salmon. To achieve this purpose, it was necessary to characterize the quantity and timing of streamflow in these rivers by developing and evaluating a distributed-parameter watershed model for a part of each river basin by using the USGS Precipitation-Runoff Modeling System (PRMS). The GIS (geographic information system) Weasel, a USGS software application, was used to delineate the four study basins and their many subbasins, and to derive parameters for their geographic features. The models were calibrated using a four-step optimization procedure in which model output was evaluated against four datasets for calibrating solar radiation, potential evapotranspiration, annual and seasonal water balances, and daily streamflows. The calibration procedure involved thousands of model runs that used the USGS software application Luca (Let us calibrate). Luca uses the Shuffled Complex Evolution (SCE) global search algorithm to calibrate the model parameters. The calibrated watershed models performed satisfactorily, in that Nash-Sutcliffe efficiency (NSE) statistic values for the calibration periods ranged from 0.59 to 0.75 (on a scale of negative infinity to 1) and NSE statistic values for the evaluation periods ranged from 0.55 to 0.73. The calibrated watershed models simulate daily streamflow at many locations in each study basin. These models enable natural resources managers to characterize the timing and amount of streamflow in order to support a variety of water-resources efforts including water-quality calculations, assessments of water use, modeling of population dynamics and migration of Atlantic salmon, modeling and assessment of habitat, and simulation of anticipated changes to streamflow and water temperature resulting from changes forecast for air temperature and precipitation.

Scientific Investigations Report↗

The Water-Quality Partnership for National Parks—U.S. Geological Survey and National Park Service, 1998–2016

The U.S. Geological Survey (USGS) and the National Park Service (NPS) work together through the USGS–NPS Water-Quality Partnership to support a broad range of policy and management needs related to high-priority water-quality issues in national parks. The program was initiated in 1998 as part of the Clean Water Action Plan, a Presidential initiative to commemorate the 25th anniversary of the Clean Water Act. Partnership projects are developed jointly by the USGS and the NPS. Studies are conducted by the USGS and findings are used by the NPS to guide policy and management actions aimed at protecting and improving water quality. The National Park Service manages many of our Nation’s most highly valued aquatic systems across the country, including portions of the Great Lakes, ocean and coastal zones, historic canals, reservoirs, large rivers, high-elevation lakes and streams, geysers, springs, and wetlands. So far, the Water-Quality Partnership has undertaken 217 projects in 119 national parks. In each project, USGS studies and assessments ( http://water.usgs.gov/nps_partnership/pubs.php ) have supported science-based management by the NPS to protect and improve water quality in parks. Some of the current projects are highlighted in the NPS Call to Action Centennial initiative, Crystal Clear, which celebrates national park water-resource efforts to ensure clean water for the next century of park management ( http://www.nature.nps.gov/water/crystalclear/ ). New projects are proposed each year by USGS scientists working in collaboration with NPS staff in specific parks. Project selection is highly competitive, with an average of only eight new projects funded each year out of approximately 75 proposals that are submitted. Since the beginning of the Partnership in 1998, 189 publications detailing project findings have been completed. The 217 studies have been conducted in 119 NPS-administered lands, extending from Denali National Park and Preserve in Alaska to Everglades National Park in Florida, and from Acadia National Park in the Northeast to park lands in Hawaii and Pacific Island territories in the West. Project goals range from periodic stream monitoring, to determining the occurrence and concentrations of contaminants and the potential for them to exceed human health or aquatic life criteria, to conducting interpretive studies to evaluate the effect(s) on or vulnerability of national park resources to visitor usage and other natural and anthropogenic activities.

Fact Sheet↗

Persistence at distributional edges: Columbia spotted frog habitat in the arid Great Basin, USA

A common challenge in the conservation of broadly distributed, yet imperiled species is understanding which factors facilitate persistence at distributional edges, locations where populations are often vulnerable to extirpation due to changes in climate, land use, or distributions of other species. For Columbia spotted frogs (Rana luteiventris) in the Great Basin (USA), a genetically distinct population segment of conservation concern, we approached this problem by examining (1) landscape-scale habitat availability and distribution, (2) water body-scale habitat associations, and (3) resource management-identified threats to persistence. We found that areas with perennial aquatic habitat and suitable climate are extremely limited in the southern portion of the species&rsquo; range. Within these suitable areas, native and non-native predators (trout and American bullfrogs [Lithobates catesbeianus]) are widespread and may further limit habitat availability in upper- and lower-elevation areas, respectively. At the water body scale, spotted frog occupancy was associated with deeper sites containing abundant emergent vegetation and nontrout fish species. Streams with American beaver (Castor canadensis) frequently had these structural characteristics and were significantly more likely to be occupied than ponds, lakes, streams without beaver, or streams with inactive beaver ponds, highlighting the importance of active manipulation of stream environments by beaver. Native and non-native trout reduced the likelihood of spotted frog occupancy, especially where emergent vegetation cover was sparse. Intensive livestock grazing, low aquatic connectivity, and ephemeral hydroperiods were also negatively associated with spotted frog occupancy. We conclude that persistence of this species at the arid end of its range has been largely facilitated by habitat stability (i.e., permanent hydroperiod), connectivity, predator-free refugia, and a commensalistic interaction with an ecosystem engineer. Beaver-induced changes to habitat quality, stability, and connectivity may increase spotted frog population resistance and resilience to seasonal drought, grazing, non-native predators, and climate change, factors which threaten local or regional persistence.

California, Idaho, Oregon, Nevada, Utah↗

Quantification of surface water and groundwater flows to open‐ and closed‐basin lakes in a headwaters watershed using a descriptive oxygen stable isotope model

Accurate quantification of hydrologic fluxes in lakes is important to resource management and for placing hydrologic solute flux in an appropriate biogeochemical context. Water stable isotopes can be used to describe water movements, but they are typically only effective in lakes with long water residence times. We developed a descriptive time series model of lake surface water oxygen‐18 stable isotope signature ( δL ) that was equally useful in open‐ and closed‐basin lakes with very different hydrologic residence times. The model was applied to six lakes, including two closed‐basin lakes and four lakes arranged in a chain connected by a river, located in a headwaters watershed. Groundwater discharge was calculated by manual optimization, and other hydrologic flows were constrained by measured values including precipitation, evaporation, and streamflow at several stream gages. Modeled and observed δL were highly correlated in all lakes ( r = 0.84–0.98), suggesting that the model adequately described δL in these lakes. Average modeled stream discharge at two points along the river, 16,000 and 11,800 m 3 d −1 , compares favorably with synoptic measurement of stream discharge at these sites, 17,600 and 13,700 m 3 d −1 , respectively. Water yields in this watershed were much higher, 0.23–0.45 m, than water yields calculated from gaged streamflow in regional rivers, approximately 0.10 m, suggesting that regional groundwater discharge supports water flux through these headwaters lakes. Sensitivity and robustness analyses also emphasized the importance of considering hydrologic residence time when designing a sampling protocol for stable isotope use in lake hydrology studies.

Water Resources Research↗

Estimated water use in Mississippi, 1980

Large quantities of good quality ground and surface water are readily available in nearly all parts of Mississippi, and there is also an abundant supply of saline water in the estuaries along the Mississippi Gulf Coast. The total estimated water use in the State in 1980 from groundwater and surface water was 3532 million gallons/day (mgd), including 662 mgd of saline water. Freshwater used from all sources in Mississippi during the period 1975 through 1980 increased from 2510 mgd to > 2870 mgd, a 14% increase. Although modest increases of freshwater use may be expected in public, self-supplied industrial, and thermoelectric supplies, large future increases in the use of freshwater may be expected primarily as a result of growth in irrigation and aquaculture. Management and protection of the quantity and quality of the available freshwater supply are often problems associated with increased use. Water use data, both temporal and spatial, are needed by the State of Mississippi to provide for intelligent, long-term management of the resources; one table gives data on the principal categories of water use, sources, and use by county. (Lantz-PTT)

Open-File Report↗

Water-resources activities in New York, 1985-86

The U.S. Geologic Survey conducts water-resources investigations and hydrologic data collection in all states to provide the data and understanding needed for optimum use and management of the nation 's surface water and groundwater. This is achieved through jointly funded programs with state, county, municipal, and other Federal agencies. The Geological Survey conducted 37 water resources investigations in New York during 1985-86, several of which are continuous. This report describes each project in terms of problems, objectives, progress to date, and future plans and gives the period of funding, project chief, principal coordinating agency, field location, and completed reports. It also lists all reports resulting from the Survey 's water resources studies in New York during 1982-86. (USGS)

Open-File Report↗

Preface; Water quality of large U.S. rivers; results from the U.S. Geological Survey's National Stream Quality Accounting Network

The mission of the US Geological Survey (USGS) is to assess the quantity and quality of the earth resources of the USA and to provide information that will assist resource managers and policymakers at federal, state and local levels in making sound decisions. Characterizing the water quality of the largest rivers of the USA is a daunting prospect, especially given the resources available for the task. The most effective approach is uncertain and is legitimately a research topic. The National Stream Quality Accounting Network (NASQAN) was redesigned in 1995 to estimate the annual mass flux of constituents at a network of fixed stations in the Mississippi, Rio Grande, Colorado, and Columbia River basins. This special volume of Hydrological Processes contains a series of papers evaluating the data collected by NASQAN during its first 3 years of operation under this design. The NASQAN network complements other USGS national programs that are designed to address water quality at different scales. The National Water-Quality Assessment Program (Hirsch et al., 1988) is designed around river basins of 10 000 to 100 000 km2 (versus these NASQAN basins, which are 650 000 to 3 100 000 km2 at their most downstream stations). The USGS also operates the Hydrologic Benchmark Network that is focused on relatively pristine basins of only 10 to 100 km2 (Mast and Turk, 1999a,b; Clark et al., 2000; Mast et al., 2000).

Hydrological Processes↗

U.S. Geological Survey Activities Related to American Indians and Alaska Natives Fiscal Year 1998

Introduction The U.S. Geological Survey (USGS) is an impartial scientific organization that strives to produce scientific results that are relevant to the people of the United States and their land and resource managers. In cooperation with American Indian and Alaska Native governments, the USGS conducts research on water and mineral resources, animals and plants of environmental, economic, or subsistence importance, natural hazards, and geologic resources. Digital data on cartography, mineral resources, stream flows, biota, and other data sets are available to American Indian and Alaska Native institutions. The USGS recognizes the need learn from and to share knowledge with Native peoples. This report describes most of the activities that the USGS conducted with American Indian and Alaska Native governments, educational institutions, and individuals during Federal fiscal year 1998.

Report↗