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At least 1,639 records · Page 91Linked to original sources

USGS2023

Adjusting design floods for urbanization across groundwater-dominated watersheds of Long Island, NY

The magnitude and variability of floods have increased for many nontidal streams on Long Island (LI), NY since the mid-20th century. One of the most densely populated regions of the United States, LI has experienced amplified floods in step with increases in impervious land cover, storm, and sanitary sewers that have accompanied urban development. To better understand the drivers of observed flood trends and effects of urbanization, a nonstationary flood frequency analysis is conducted, using historical annual peak flow records from 17 gaged watersheds on LI using conditional moments based on physical covariates from a two-stage sequential robust linear regression procedure. Regression results indicate that urban development and precipitation are significant co-predictors of peak flows for LI watersheds that have undergone rapid development during the available peak flow record. In watersheds with less intense urbanization or that were fully developed before the peak flow record began, precipitation alone was a significant explanatory variable. Long-term baseflow patterns identified using a nonparametric smoother explained some patterns of decreasing peak flows and heteroskedasticity in the peak flow records. Fitting a log-Pearson III distribution with these conditional moments, floods corresponding to a 20% annual exceedance probability (AEP) are up to 80% higher under a nonstationary framework compared with stationary under current watershed conditions, and differ significantly (95% confidence) from stationary estimates for 6 out of 17 watersheds. Larger floods corresponding to 1% AEPs do not differ significantly between nonstationary and stationary estimates at a 95% confidence level. Nonmonotonic trends observed in two watersheds indicate that recent stormwater management practices, such as rerouting stormwater outfalls away from the channel, substantially reduce flood frequency. Reduced nonstationary flood quantile estimates at these two watersheds are 20 to 40% lower than stationary estimates when accounting for changing watershed conditions over time. Across LI, stormwater management and water-table fluctuations have increased peak flow variability, characteristic of a late phase urban adjustment period on LI. Results of this study demonstrate that a nonstationary framework is a necessary step forward toward a regional flood-frequency analysis for LI. This nonstationary framework will allow flood managers to update flood discharge estimates to current conditions that reflect altered relationships between urban cover and climate for more targeted planning of flood control, transportation infrastructure, and management of floodplain ecosystems.

New York↗

USGS1976

Time of travel of solutes in the East Fork Trinity River, November 1975; and Elm Fork Trinity River, December 1975; Trinity River basin, Texas

The U.S. Geological Survey, in cooperation with the North Central Texas Council of Governments, the Trinity River Authority of Texas, and the Texas Water Development Board, conducted two time-of-travel studies in the Trinity River basin in November and December, 1975. Field data were collected on the East Fork Trinity River during November 18-22, 1975, and on the Elm Fork Trinity River during December 8-13, 1975. The purpose of these two studies was to provide data that could be used by the Trinity River Authority and the Texas Water Quality Board in the development of a mathematical water-quality model of the two streams. The model is to be used in a comprehensive water-quality management plan for the Trinity River basin.

Texas↗

USGS1999

A plan for assessing the occurrence and distribution of methyl tert-butyl ether and other volatile organic compounds in drinking water and ambient ground water in the Northeast and Mid-Atlantic regions of the United States

A plan to assess the occurrence and distribution of methyl tert-butyl ether (MTBE) and other volatile organic compounds (VOCs) in drinking water and ambient ground water in the Northeast and Mid-Atlantic regions of the United States was designed to meet two primary objectives. This study will provide the U.S. Environmental Protection Agency with information on potential human exposure to MTBE and other VOCs from drinking water. In addition, the study will further the goals of the U.S. Geological Survey's (USGS) National Water Quality Assessment Program (NAWQA) by providing additional information on the occurrence and distribution of VOCs in ambient ground water beneath a large, highly urbanized part of the Nation. The study will proceed in two phases-a drinking-water assessment (phase 1) and an ambient ground-water assessment (phase 2). The drinking-water assessment will involve compilation, review, and analysis of available water- quality and ancillary data for approximately 20 percent of the community water systems in 12 States in the Northeast and Mid-Atlantic regions. This effort will summarize the occurrence and distribution of MTBE and other VOCs in drinking water supplied by 2,110 community water systems. The ambient ground-water assessment will involve compilation, review, and analysis of data on MTBE and other VOCs from previous USGS studies in the 12-State area, including regional water-quality assessments conducted for the USGS's NAWQA, plus other available State or local datasets. These data will be related, to the extent allowed by the completeness and quality of the data, to land-use patterns, population density, and other anthropogenic and natural factors using statistical tests. The occurrence and distribution of MTBE and other VOCs in ambient ground water and, to the extent possible, drinking water in relation to such factors, will be evaluated.

Open-File Report↗

USGS2021

Regression relations and long-term water-quality constituent concentrations, loads, yields, and trends in the North Fork Ninnescah River, south-central Kansas, 1999–2019

Cheney Reservoir, in south-central Kansas, is the primary water supply for the city of Wichita, Kansas. The North Fork Ninnescah River is the largest tributary to Cheney Reservoir and contributes about 70 percent of the inflow. The U.S. Geological Survey, in cooperation with the City of Wichita, has been continuously monitoring water quality (including water temperature, specific conductance, pH, dissolved oxygen, and turbidity) on the North Fork Ninnescah River upstream from Cheney Reservoir (U.S. Geological Survey site 07144780) since November 1998. Continued data collection would be beneficial to update and describe changing water-quality conditions in the drainage basin and in the reservoir over time. Regression models were developed to describe relations between discretely measured constituent concentrations and continuously measured physical properties. The models updated in this report include total suspended solids (TSS), suspended-sediment concentration (SSC), nitrate plus nitrite, nitrate, orthophosphate (OP), total phosphorus (TP), and total organic carbon (TOC). Daily computed concentrations for TSS, TP, and nitrate plus nitrite during 1999–2019 were compared with Cheney Reservoir Task Force (CRTF) goals for base-flow and runoff conditions. CRTF goals for base-flow concentrations were exceeded more frequently (70 to 99.9 percent of the time) than runoff goals (0 to 11 percent of the time). Except for 2012, annual mean TSS concentrations exceeded the base-flow goal every year. Nitrate plus nitrite and TP annual mean concentrations exceeded the base-flow goals every year. TSS and nitrate plus nitrite annual mean concentrations during runoff conditions never exceeded the CRTF runoff goal. TP annual mean concentrations during runoff conditions only exceeded the CRTF runoff goal during 2002. Sedimentation is progressively reducing the storage capacity of Cheney Reservoir. During 1999–2019, 55 percent of the computed suspended-sediment load was transported during the top 1 percent of loading days (76 days); 22 percent of the total load was transported in the top 10 loading days, indicating that substantial parts of suspended-sediment loads continue to be delivered during disproportionately small periods in Cheney Reservoir. Successful sediment management efforts necessitate reduction techniques that account for these large load events. Flow-normalized concentrations and fluxes were computed during 1999 through 2019 using Weighted Regressions on Time, Discharge, and Season (WRTDS) statistical models and WRTDS bootstrap tests. Flow-normalized concentrations of TSS, SSC, OP, TP, and TOC had upward trend probabilities; conversely, nitrate plus nitrite had a downward trend. Flow-normalized fluxes for OP, TP, and TOC had an upward trend. No discernible patterns were identified for flow-normalized flux of TSS or suspended sediment. Nitrate plus nitrite flow-normalized flux indicated a downward trend. Flow-normalized concentrations for TSS were less than the CRTF long-term goal of 100 milligrams per liter (mg/L), but the upward trend indicated the long-term goal may be exceeded if no changes are made. Flow-normalized TP concentrations exceeded the CRTF long-term goal (0.1 mg/L) and were assigned a very likely upward trend. Flow-normalized nitrate plus nitrite concentrations exceeded the CRTF long-term goal of 1.2 mg/L during the beginning of the study period, then were less than the CRTF goal for the remainder of the study; however, during 2010–19 flow-normalized concentrations increased by 6 percent. Linking water-quality changes to causal factors requires consistent monitoring before, during, and after changes; this presents challenges related to length and frequency of data collection and available concomitant land-use and conservation practice data. As such, attribution of water-quality trends to land-use changes or conservation practices was not possible for this study because of a lack of land-use and conservation practice data. Additionally, because precipitation frequency and intensity are projected to continue to increase in the Great Plains region, accounting for extreme episodic events may be an important consideration in future sediment and nutrient load reduction plans.

Kansas↗

USGS2023

Bathymetric, hydrodynamic, biological, and water-quality characteristics of a nearshore area of the Laguna Madre near South Padre Island, Texas, 2021–22

A variety of data were collected by the U.S. Geological Survey, in cooperation with the City of South Padre Island, to better understand the physical and biological habitat in Tompkins Channel and adjacent seagrass beds in the lower Laguna Madre, Texas, where the construction of berms has been proposed in the City of South Padre Island’s Shoreline Master Plan. These berms would be used to create living shorelines, defined as shorelines that “connect the land and water to stabilize the shoreline, reduce erosion, and provide ecosystem services, like [maintaining] valuable habitat, that enhances coastal resilience.” Bathymetric surveys show variability in the lagoon depth within the study area and clearly delineate the relatively shallow bay from the deeper Tompkins Channel. There were seasonal patterns in daily mean tidal water-surface elevations, with higher mean tides in the fall and spring and lower mean tides in the winter and summer. Seasonal differences in mean tidal water-surface elevations were primarily caused by astronomical forces. Shorter-term (daily and weekly) variations in tidal water-surface elevations were produced by meteorological forcing resulting from high- and low-pressure systems, the passage of fronts, local storms, and tropical storms. The tide driven currents typically were toward the north-northwest during flood tide or toward the south-southeast during ebb tide, roughly parallel to the general South Padre Island shoreline orientation. Prevailing water current velocity (current speed and direction) indicates that there usually is a net inflow into the lower Laguna Madre from the Gulf of Mexico and a net outflow at locations north of the study area. The overall seagrass density was generally lowest in the northeast section of the transect. Areas of low seagrass density were also most commonly observed close to the channel edge of the transect. Overall, Syringodium filiforme was considerably more abundant than Thalassia testudinum and Halodule wrightii . Amphipods from the families Ampithoidae and Melitidae were the most abundant benthic invertebrates, followed by gastropods in the family Calyptraeidae. Higher abundances of benthic invertebrates were recorded at sites farther away from Tompkins Channel than at sites closer to it, perhaps because of the sensitivity of these organisms to disturbances caused by erosional forces in the channel. Changes in water-quality measured during a 2-day survey were consistent with patterns observed in prior studies, indicating biological processes likely play an important role in the physicochemical environment of the study area. Collectively, the data provide baseline information that can be used as reference conditions prior to any shoreline enhancement activities in the lower Laguna Madre.

Texas↗

USGS2003

Surface-water-resources information for the Ho-Chunk Nation lands and vicinity, Wisconsin

The Ho-Chunk Nation is interested in documenting water-quality conditions in streams adjacent to their Reservation lands in Wisconsin and developing management plans to protect these water resources. The Nation uses these waterways for recreation and as a source for food, and therefore, is dedicated to maintaining and restoring their quality. Ho-Chunk lands encompass more than 10,000 acres ranging primarily over 17 counties in Wisconsin. The study areas for this report include streams adjacent to Ho-Chunk Nation residential lands: Potch-Hah-Chee, Sandpillow, Mission, Bluewing, Chakh Hah Chee, Winnebago Heights, Indian Heights, and Ho-Chunk Village. These residential areas, or housing sites, are located along or near the Middle Branch Embarrass, Black, Lemonweir, and Wisconsin Rivers or their tributaries. Water-quality data were compiled and summarized, and basin maps showing land cover and previous sampling sites are presented. Qualitative assessments of factors that could potentially affect water quality were summarized from the literature. Quantitative data were available from several studies (more than 5) for the Potch-Hah-Chee area, few studies (1?5) for the Sandpillow, Mission, Ho-Chunk Village, and Indian Heights areas, and no studies for the Bluewing, Chakh Hah Chee, and Winnebago Heights areas. Data analysis was limited to averaging basic water-quality constituents for the Middle Branch Embarrass River in the Potch-Hah-Chee area. The mainstem Wisconsin and Black Rivers have been extensively studied elsewhere and are not independently re-evaluated here. Qualitative assessments indicate that agricultural activities are the main contributing factor to water quality and fish habitat problems in the studied areas. Index of Biotic Integrity ratings, based on fish data, were available for 5 sites on 3 streams. Hilsenhoff Biotic Index ratings, based on macroinvertebrate data, were available for 21 sites on 4 streams. This information will serve as baseline data and as a guide to ongoing study and management of these waters by the Ho-Chunk Nation.

Wisconsin↗

USGS1930

The Green River and its utilization

The purpose of this report is to present the facts regarding the available water supply of the Green River Basin and other data that will be helpful in planning to put this water to beneficial use. For some parts of the basin a mass of information is available; for other parts the data are less complete. An attempt is made in this report to present an analysis of all this information, supplemented by personal field studies, in such a way as to indicate the economic factors involved in utilizing the waters of the basin, and also to give facts from which the relative value of the irrigation and power projects may be readily deduced.

Green River↗

USGS1995

Effects of fire on threatened and endangered plants: an annotated bibliography

This bibliography presents basic information about the effects of fm on plants that the U.S. Fish and Wildlife Service lists as endangered or threatened or as category-one (Cl) candidates for federal listing. We searched 23 databases for publications, unpublished reports, and records with pertinent information; summarized and compiled information on the effects of fire from all final rulings on endangered and threatened plants and from endangered species recovery plans for plants; and solicited information from key researchers and agencies involved in fire ecology. The bibliography includes 126 references to the effect of fire on 172 federally listed plant species, or on 26% of the total number of federally listed plant species in these categories. Our study revealed that the total number of relevant articles has been increasing since the 1970s and more rapidly since the 1980s. Although research on fire and rare plants is increasing, an absence of information on many species persists. We hope that this document will facilitate and encourage research in this increasingly important field of botanical conservation.

Information and Technology Report↗

USGS2016

A field ornithologist’s guide to genomics: Practical considerations for ecology and conservation

Vast improvements in sequencing technology have made it practical to simultaneously sequence millions of nucleotides distributed across the genome, opening the door for genomic studies in virtually any species. Ornithological research stands to benefit in three substantial ways. First, genomic methods enhance our ability to parse and simultaneously analyze both neutral and non-neutral genomic regions, thus providing insight into adaptive evolution and divergence. Second, the sheer quantity of sequence data generated by current sequencing platforms allows increased precision and resolution in analyses. Third, high-throughput sequencing can benefit applications that focus on a small number of loci that are otherwise prohibitively expensive, time-consuming, and technically difficult using traditional sequencing methods. These advances have improved our ability to understand evolutionary processes like speciation and local adaptation, but they also offer many practical applications in the fields of population ecology, migration tracking, conservation planning, diet analyses, and disease ecology. This review provides a guide for field ornithologists interested in incorporating genomic approaches into their research program, with an emphasis on techniques related to ecology and conservation. We present a general overview of contemporary genomic approaches and methods, as well as important considerations when selecting a genomic technique. We also discuss research questions that are likely to benefit from utilizing high-throughput sequencing instruments, highlighting select examples from recent avian studies.

The Auk↗

USGS1970

Remote Sensor Application Studies Progress Report, July L, 1968 to June 30, 1969. Controlled Field Experiments

Field Sites have been selected for controlled experiments to analyze physical and chemical parameters affecting the response of electromagnetic radiation to geological materials. Considerations in the selection of the sites are the availability of good exposures of nearly monomineralic rocks, level of geologic understanding, and ease of access. Seven sites, where work is underway or planned, contain extensive outcrops of the following rocks: stanstone, limestone, dolomite, and gypsum. Field measurement of quartz have been conducted at four sites.

Report↗

USGS2014

Advantages of active love wave techniques in geophysical characterizations of seismographic station - Case studies in California and the central and eastern United States

Active-source Love waves, recorded by the multi-channel analysis of surface wave (MASLW) technique, were recently analyzed in two site characterization projects. Between 2010 and 2012, the 2009 American Recovery and Reinvestment Act (ARRA) funded GEOVision to conduct geophysical investigations at 191 seismographic stations in California and the Central Eastern U.S. (CEUS). The original project plan was to utilize active and passive Rayleigh wave-based techniques to obtain shear-wave velocity (VS) profiles to a minimum depth of 30 m and the time-averaged VS of the upper 30 meters (VS30). Early in this investigation it became clear that Rayleigh wave techniques, such as multi-channel analysis of surface waves (MASRW), were not suited for characterizing all sites. Shear-wave seismic refraction and MASLW techniques were therefore applied. In 2012, the Electric Power Research Institute funded characterization of 33 CEUS station sites. Based on experience from the ARRA investigation, both MASRW and MASLW data were acquired by GEOVision at 24 CEUS sites. At shallow rock sites, sites with steep velocity gradients, and, sites with a thin, low velocity, surficial soil layer overlying stiffer sediments, Love wave techniques generally were found to be easier to interpret, i.e., Love wave data typically yielded unambiguous fundamental mode dispersion curves and thus, reduce uncertainty in the resultant VS model. These types of velocity structure often excite dominant higher modes in Rayleigh wave data, but not in the Love wave data. It is possible to model Rayleigh wave data using multi- or effective-mode techniques; however, extraction of Rayleigh wave dispersion data was found to be difficult in many cases. These results imply that field procedures should include careful scrutiny of Rayleigh wave-based dispersion data in order to also collect Love wave data when warranted.

Conference Paper↗

USGS2005

Winter ice processes and pool habitat associated with two types of constructed instream structures

There is little information on the winter features of salmonid habitats associated with constructed instream structures to provide guidance when planning habitat improvement projects. We assessed winter habitat features for trout of the genera Oncorhynchus and Salvelinus in pools associated with two types of instream structures constructed on a low-gradient reach of a mountain stream in western Wyoming with a mean wetted width of 6.4 m. Pool habitat was affected by temporal variability in ice formations from fall into winter. As surface ice and snow accumulated with the progression of winter, variation in ice formations was less frequent and winter habitat conditions became more stable. However, groundwater inflow that maintained water temperatures at 0.2-0.6??C in a portion of the study reach appeared to contribute to incomplete surface ice cover and variation in ice formations in pools through most of the winter. Hanging dams and anchor ice dams were the primary ice features that affected winter habitat in pools associated with constructed instream structures. Trout were observed in these pools in the fall but tended to abandon pools with variation in ice formations as winter progressed. The potential impacts of groundwater inflow and winter ice processes on trout habitat in pools associated with instream structures should be considered when planning habitat improvement projects. ?? Copyright by the American Fisheries Society 2005.

North American Journal of Fisheries Management↗

USGS2012

Exploring relationships among land ownership, agricultural land use, and native fish species richness in the Upper Mississippi River Basin

The general effects of agriculture on in-stream fish communities in the Upper Midwestern United States have been well studied for nearly three decades (Karr et al. 1985; Nerbonne and Vondracek 1991; Zimmerman et al. 2001; Goldstein and Meador 2005). Specific impacts include: lowered water levels, sediment loading and nutrient enrichment, loss of riparian habitat, changes to channel morphometry and physical habitat, and changes to the forage base. As part of the National Fish Habitat Action Plan (NFHAP), an initiative to protect, restore, and enhance the nation's fish and aquatic communities, the Fishers and Farmers Partnership specifically focuses on working with agricultural producers to help protect and restore aquatic resources in the Upper Mississippi River Basin (UMRB) (Fig. 1). Successful protection and/or restoration will require the partnership and local conservation agencies to effectively communicate and work with local landowners. However, roughly 43% of the agricultural lands in the UMRB are not operated by those who own the land (National Agricultural Statistics Service 2009) and this is expected to increase as heirs of farm estates now reside greater distances from their home farms than ever before (Arbuckle 2010). It has long been presumed that changes in land ownership trends, toward more absentee landowners, would have important consequences for soil erosion and other conservation practices, as larger, more corporate agriculture, is thought to maximize farm income at the expense of environmental quality (Lee 1980). Absentee landowners may be less likely to take advantage of conservation programs. For example, land operated by renters lags enrollment in the Conservation Reserve (CRP) and Wetland Reserve (WRP) programs by 64% nation-wide (Petrzelka et al. 2009). Also, it has been found that the more detached an absentee landowner becomes from their land, both geographically and culturally, their commitment to land stewardship decreases (Arbuckle 2010). The Fishers and Farmers Partnership recognizes the challenge agricultural producers face in maintaining food and fiber production for a growing world population while also trying to improve environmental quality and fish habitat. This challenge is likely exacerbated when the landowners are absentee. Thus, reaching non-owner-operated farmers and convincing them to help protect and/or restore aquatic resources may be critical to the success of the Fishers and Farmers Partnership. In this study, we explored relationships among agricultural land use, land ownership, and native fish biodiversity in the UMRB as a first step toward helping the Fishers and Farmers Partnership identify specific locations in the UMRB that may pose conservation challenges. For example, places that have experienced a loss of native fish species richness relative to historical conditions and also have high proportions of absentee landowners may provide restoration challenges. We were also interested in identifying areas that have retained high levels of species richness and are owner-operated. These areas present good opportunities to work with local landowners to protect aquatic resources. To identify such areas, we addressed two primary questions: 1) Is there a relationship between the type of agricultural land use (i.e. cropland vs pastureland) and the % of land rented or leased within the UMRB? and 2) How does the type of agricultural production and whether land is rented or leased relate to the maintenance of historical levels of native fish species richness? We predicted that areas with large amounts of land devoted to crop production will have experienced the greatest losses of native fish species richness. However, our hypothesis is that watersheds with large amounts of land rented or leased will have experienced even greater declines in native fish species richness than would be predicted from the amount of cultivated cropland alone. By testing these hypotheses, we intended to identify watersheds that would be strong candidates for protection, restoration, and enhancement of fish species richness by accounting for land use and ownership characteristics.

Illinois, Indiana, Iowa, Michigan, Minnesota, Miss↗

USGS2012

Directional connectivity in hydrology and ecology

Quantifying hydrologic and ecological connectivity has contributed to understanding transport and dispersal processes and assessing ecosystem degradation or restoration potential. However, there has been little synthesis across disciplines. The growing field of ecohydrology and recent recognition that loss of hydrologic connectivity is leading to a global decline in biodiversity underscore the need for a unified connectivity concept. One outstanding need is a way to quantify directional connectivity that is consistent, robust to variations in sampling, and transferable across scales or environmental settings. Understanding connectivity in a particular direction (e.g., streamwise, along or across gradient, between sources and sinks, along cardinal directions) provides critical information for predicting contaminant transport, planning conservation corridor design, and understanding how landscapes or hydroscapes respond to directional forces like wind or water flow. Here we synthesize progress on quantifying connectivity and develop a new strategy for evaluating directional connectivity that benefits from use of graph theory in ecology and percolation theory in hydrology. The directional connectivity index (DCI) is a graph-theory based, multiscale metric that is generalizable to a range of different structural and functional connectivity applications. It exhibits minimal sensitivity to image rotation or resolution within a given range and responds intuitively to progressive, unidirectional change. Further, it is linearly related to the integral connectivity scale length—a metric common in hydrology that correlates well with actual fluxes—but is less computationally challenging and more readily comparable across different landscapes. Connectivity-orientation curves (i.e., directional connectivity computed over a range of headings) provide a quantitative, information-dense representation of environmental structure that can be used for comparison or detection of subtle differences in the physical-biological feedbacks driving pattern formation. Case-study application of the DCI to the Everglades in south Florida revealed that loss of directional hydrologic connectivity occurs more rapidly and is a more sensitive indicator of declining ecosystem function than other metrics (e.g., habitat area) used previously. Here and elsewhere, directional connectivity can provide insight into landscape drivers and processes, act as an early-warning indicator of environmental degradation, and serve as a planning tool or performance measure for conservation and restoration efforts.

Ecological Applications↗

USGS1995

Evaluation of nonpoint-source contamination, Wisconsin; selected streamwater-quality data, land-use and best-management practices inventory, and quality assurance and quality control, water year 1993

The objective of the watershed-management evaluation monitoring program in Wisconsin is to evaluate the effectiveness of the best-management practices (BMPs) for rural streams, urban streams, and urban storm sewers. This report is an annual summary of the data collected for the program and a report of the results from several different special studies conducted within this program. Suspended sediment and total phosphorus storm-load data are summarized for eight rural sites and suspended sediment, total phosphorus, total recoverable lead, total recoverable copper, total recoverable zinc, and total recoverable cadmium storm-load data are summarized for four urban sites. Dissolved-oxygen data is summarized and compared with Wisconsin's waterquality standards for summer 1993 for seven rural sites. The dissolved-oxygen concentrations declined to levels below these standards at least one time at all seven sites during summer 1993. Total-recoverable hardness concentrations were compared with dissolved-hardness concentrations at two urban streams and two urban storm sewers. Least-squared linear regressions resulted in stronger relations for low-flow conditions than for high-flow conditions, indicating that most hardness during low flow is dissolved hardness. Pesticide data are summarized for four urban sites and six rural sites. Herbicides were detected at urban and rural sites; whereas insecticides were detected only at urban sites. A land-use and best-management-practice inventory is ongoing for each evaluation monitoring project to track the different sources of nonpoint pollution in each watershed and to document implementation of best-management programs that may cause changes in water quality of streams. Updated information is gathered each year, mapped, and stored in a geographic-information-system data base. The quality-assurance/quality-control plan for the urban watershed-management evaluation program consisted of a series of blank samples. These blank samples were used to identify and isolate contamination by inorganic and organic components throughout the collection and processing of urban streamwater samples. A dissolved trace-metal contamination problem was identified and resolved by using different laboratory- supplied sample bottles. A special study was done to determine the effect of holding time on fecal coliform colony counts. A linear regression indicated that the mean decrease in colony counts over 72 hours was 8.2 percent per day. Results after 24 hours showed that colony counts increased in some samples and decreased in others.

Wisconsin↗

USGS2016

Spatial and temporal variation in positioning probability of acoustic telemetry arrays: Fine-scale variability and complex interactions

Background As popularity of positional acoustic telemetry systems increases, so does the need to better understand how they perform in real-world applications, where variation in performance can bias study conclusions. Studies assessing variability in positional telemetry system performance have focused primarily on position accuracy, or comparing performance inside and outside the array. Here, we explored spatial and temporal variation in positioning probability within a 140-receiver Vemco Positioning System (VPS) array used to monitor lake trout, Salvelinus namaycush , spawning behavior over 23 km 2 in Lake Huron, North America. Methods Variability in VPS positioning probability was assessed between August and November from 2012 to 2014 using 43 stationary transmitters distributed throughout the array. Various analyses were used to relate positioning probability to number of fish transmitters in the array, wave height, and thermal stratification. We also assessed the prevalence of ‘close proximity detection interference’ (CPDI) in our array by analyzing detection probability of 35 transmitters on collocated receivers. Results Positioning probability of the VPS array varied greatly over time and space. Number of fish transmitters present in the array was a significant driver of reduced positioning probability, especially during lake trout spawning period when the fish were aggregated. Relationships between positioning probability and environmental variables were complex and varied over small spatial and temporal scales. One possible confounding variable was the large range of water depth over which receivers were deployed. Another confounding factor was the high prevalence of CPDI, which decreased exponentially with water depth and was less evident when wave heights were higher than normal. Conclusions Some variables that negatively influenced positioning can be minimized through careful planning (e.g., number of tagged fish released, transmitter power level). However, results suggested that the acoustic environment was highly variable over small spatial and temporal scales in response to complex interactions between many variables. Therefore, models that predict positioning or detection efficiencies as a function of environmental variables may not be attainable in most systems. The best defense against biased study conclusions is incorporation of in situ measures of system performance that allow for retrospective analysis of array performance after a study is completed. Keywords Vemco Positioning System Positional telemetry Performance Detection probability Close proximity detection interference Thermal stratification Wave height Signal code collision

Animal Biotelemetry↗

USGS2017

Functional integrity of freshwater forested wetlands, hydrologic alteration, and climate change

Climate change will challenge managers to balance the freshwater needs of humans and wetlands. The Intergovernmental Panel on Climate Change predicts that most regions of the world will be exposed to higher temperatures, CO 2 , and more erratic precipitation, with some regions likely to have alternating episodes of intense flooding and mega-drought. Coastal areas will be exposed to more frequent saltwater inundation as sea levels rise. Local land managers desperately need intra-regional climate information for site-specific planning, management, and restoration activities. Managers will be challenged to deliver freshwater to floodplains during climate change-induced drought, particularly within hydrologically altered and developed landscapes. Assessment of forest health, both by field and remote sensing techniques, will be essential to signal the need for hydrologic remediation. Studies of the utility of the release of freshwater to remediate stressed forested floodplains along the Murray and Mississippi Rivers suggest that brief episodes of freshwater remediation for trees can have positive health benefits for these forests. The challenges of climate change in forests of the developing world will be considered using the Tonle Sap of Cambodia as an example. With little ecological knowledge of the impacts, managing climate change will add to environmental problems already faced in the developing world with new river engineering projects. These emerging approaches to remediate stressed trees will be of utmost importance for managing worldwide floodplain forests with predicted climate changes.

Ecosystem Health and Sustainability↗

USGS2006

Trophic structure and avian communities across a salinity gradient in evaporation ponds of the San Francisco Bay estuary

Commercial salt evaporation ponds comprise a large proportion of baylands adjacent to the San Francisco Bay, a highly urbanized estuary. In the past two centuries, more than 79% of the historic tidal wetlands in this estuary have been lost. Resource management agencies have acquired more than 10 000 ha of commercial salt ponds with plans to undertake one of the largest wetland restoration projects in North America. However, these plans have created debate about the ecological importance of salt ponds for migratory bird communities in western North America. Salt ponds are unique mesohaline (5–18 g l −1 ) to hyperhaline (> 40 g l −1 ) wetlands, but little is known of their ecological structure or value. Thus, we studied decommissioned salt ponds in the North Bay of the San Francisco Bay estuary from January 1999 through November 2001. We measured water quality parameters (salinity, DO, pH, temperature), nutrient concentrations, primary productivity, zooplankton, macroinvertebrates, fish, and birds across a range of salinities from 24 to 264 g l −1 . Our studies documented how unique limnological characteristics of salt ponds were related to nutrient levels, primary productivity rates, invertebrate biomass and taxa richness, prey fish, and avian predator numbers. Salt ponds were shown to have unique trophic and physical attributes that supported large numbers of migratory birds. Therefore, managers should carefully weigh the benefits of increasing habitat for native tidal marsh species with the costs of losing these unique hypersaline systems.

California↗