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At least 865 records · Page 48Linked to original sources
USGS2015

Targeting climate diversity in conservation planning to build resilience to climate change

Climate change is raising challenging concerns for systematic conservation planning. Are methods based on the current spatial patterns of biodiversity effective given long-term climate change? Some conservation scientists argue that planning should focus on protecting the abiotic diversity in the landscape, which drives patterns of biological diversity, rather than focusing on the distribution of focal species, which shift in response to climate change. Climate is one important abiotic driver of biodiversity patterns, as different climates host different biological communities and genetic pools. We propose conservation networks that capture the full range of climatic diversity in a region will improve the resilience of biotic communities to climate change compared to networks that do not. In this study we used historical and future hydro-climate projections from the high resolution Basin Characterization Model to explore the utility of directly targeting climatic diversity in planning. Using the spatial planning tool, Marxan, we designed conservation networks to capture the diversity of climate types, at the regional and sub-regional scale, and compared them to networks we designed to capture the diversity of vegetation types. By focusing on the Conservation Lands Network (CLN) of the San Francisco Bay Area as a real-world case study, we compared the potential resilience of networks by examining two factors: the range of climate space captured, and climatic stability to 18 future climates, reflecting different emission scenarios and global climate models. We found that the climate-based network planned at the sub-regional scale captured a greater range of climate space and showed higher climatic stability than the vegetation and regional based-networks. At the same time, differences among network scenarios are small relative to the variance in climate stability across global climate models. Across different projected futures, topographically heterogeneous areas consistently show greater climate stability than homogenous areas. The analysis suggests that utilizing high-resolution climate and hydrological data in conservation planning improves the likely resilience of biodiversity to climate change. We used these analyses to suggest new conservation priorities for the San Francisco Bay Area.

Ecosphere↗
USGS1980

Distribution of nitrate in the unsaturated zone, Highland-East Highlands area, San Bernardino County, California

Nitrogen in the unsaturated soil zone in the Highland-East Highlands area of San Bernardino County, Calif., has been suspected as the source of nitrate in water from wells. Plans to recharge the local aquifers with imported surface water would raise the water table and intercept that nitrogen. This study was made to describe the distribution of inorganic nitrogen and other chemical constituents and nitrogen-using bacteria in the unsaturated zone, to relate nitrogen occurrences, in a general way, to present and historical land use, and to attempt to predict nitrogen concentrations in ground water after recharge. Some generalized correlations between nitrogen occurrence and land use were observed. In 11 of 13 test holes, the maximum nitrate-nitrogen (NO 3 - -N) concentrations occurred within 10 feet of the surface, suggesting that the major source of nitrogen is from the surface at these sites. Test holes were ranked according to maximum NO 3 - -N in the top 10 feet, total NO 3 - -N in the top 10 feet, and total NO 3 - -N in the top 40 feet. In all three rankings, the top seven test holes were the same--five in or near present or historical agricultural areas (primarily citrus groves), one in a feedlot, and one adjacent to an abandoned sewage-treatment plant. Two test holes in historically uninhabited areas ranked lowest. The control test hole in an uninhabited area ranked high in geometric mean of ammonium-nitrogen concentration (NH 4 + -N), suggesting that present in freshly weathered granite. The geometric means of NH 4 + -N concentrations in six of eight citrus-related test holes were significantly lower than in the control hole, suggesting that irrigation in citrus groves may have created conditions favoring nitrification of the primary NH 4 + -N. Rank correlation analyses between various measurements in test holes showed that high NO 3 - -N concentrations tend to occur with high specific conductance and chloride concentrations in soil extracts. If recharge is carried out as planned, assuming complete mixing of the recharge water and interstitial pore water in the top 20 feet of the saturated zone, NO 3 - -N concentrations in water at the top of the saturated zone may exceed 10 milligrams per liter in seven areas studied. Concentrations could reach as high as 66 milligrams per liter in the worst case projected. The highest concentrations may be found in three areas that are now, or were recently, citrus groves.

California↗
USGS2023

Broadening benefits and anticipating tradeoffs with a proposed ecosystem service analysis framework for the US Army Corps of Engineers

Would-be adopters of ecosystem service analysis frameworks might ask, ‘Do such frameworks improve ecosystem service provision or social benefits sufficiently to compensate for any extra effort?’ Here we explore that question by retrospectively applying an ecosystem goods and services (EGS) analysis framework to a large river restoration case study conducted by the US Army Corps of Engineers (USACE) and comparing potential time costs and outcomes of traditional versus EGS-informed planning. USACE analytic methods can have a large influence on which river and wetland restoration projects are implemented in the United States because they affect which projects or project elements are eligible for federal cost-share funding. A new framework is designed for the USACE and is primarily distinguished from current procedures by adding explicit steps to document and compare tradeoffs and complementarity among all affected EGS, rather than the subset that falls within project purposes. Further, it applies economic concepts to transform ecological performance indicators into social benefit indicators, even if changes cannot be valued. We conclude that, for large multi-partner restoration projects like our case study, using the framework provides novel information on social outcomes that could be used to enhance project design, without substantially increasing scoping costs. The primary benefits of using the framework in the case study appeared to stem from early comprehensive identification of stakeholder interests that might have prevented project delays late in the process, and improving the communication of social benefits and how tradeoffs among EGS benefits were weighed during planning.

Missouri↗
USGS1980

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Little Lick and Big Lick Creeks, Blackford and Delaware counties, Indiana

The Indiana State Board of Health is developing a State water-quality management plan that includes establishing limits for liquid wastes discharged into Indiana streams. A digital computer model was used to predict alternatives for future waste loadings on Little Lick and Big Lick Creeks that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The model parameters included atmospheric reaeration, carbonaceous and nitrogenous biochemical-oxygen demand, and benthic-oxygen demand. The model was calibrated with data collected during three water-quality surveys at low flow. Verification of the model was not possible owing to varied effluent discharge during sampling. During these surveys, in-stream dissolved-oxygen concentration averaged less than 3 milligrams per liter, well below the State minimum requirement of 5.0 milligrams per liter. The model indicated that these low concentrations were caused by high waste loadings, lack of dilution, low reaeration, and benthic-oxygen demand. The hypothetical summer waste-assimilation study assumed that future reductions in discharge Loadings would decrease carbonaceous and benthic decay and increase nitrogenous decay. This hypothetical study indicated that projected effluent waste loads that would provide acceptable in-stream dis-solved-oxygen concentrations are highly dependent on rates of nitrification. Ammonia toxicity became the limiting water-quality criterion at low nitrification rates. The hypothetical winter waste-assimilation study indicated that projected dissolved-oxygen concentrations in Little Lick and Big Lick Creeks did not fall below the State standard. Owing to a lack of dilution, however, ammonia-nitrogen concentrations would violate in-stream toxicity standards in both Little Lick and Big Lick Creeks. In order to quantify the results of the waste-assimilation study, it would be necessary to collect additional stream data.

Indiana↗
USGS2018

Evaluation of sockeye salmon after passage through an innovative upstream fish-passage system at Cle Elum Dam, Washington, 2017

Executive Summary The Bureau of Reclamation (Reclamation) and the Washington State Department of Ecology (Ecology), working with the Yakima River Basin Water Enhancement Project Workgroup (composed of representatives of the Yakama Nation; Federal, State, county, and city governments; environmental organizations; and irrigation districts), developed the Yakima Basin Integrated Plan (Integrated Plan). The Integrated Plan identifies a comprehensive approach to water resources and ecosystem restoration improvements in the Yakima Basin to be implemented over a 30-year period. The Integrated Plan includes seven elements: Reservoir fish passage, Structural and operational changes to existing facilities, Surface water storage, Groundwater storage, Habitat/watershed protection and enhancement, Enhanced water conservation, and Market reallocation. The first listed element, reservoir fish passage, will be expensive and take many years to accomplish. Reclamation and Ecology decided to look at new and innovative means to provide passage that could help reduce project cost and construction timing while maintaining survival rates of traditional upstream passage facilities. Reclamation contracted with the U.S. Geological Survey to do a study to evaluate the outcome of passage through one innovative fish-passage system at Cle Elum Dam, the first Integrated Plan reservoir fish-passage project being implemented.

Washington↗
USGS2017

Bridge scour countermeasure assessments at select bridges in the United States, 2014–16

In 2009, the Federal Highway Administration published Hydraulic Engineering Circular No. 23 (HEC-23) to provide specific design and implementation guidelines for bridge scour and stream instability countermeasures. However, the effectiveness of countermeasures implemented over the past decade following those guidelines has not been evaluated. Therefore, in 2013, the U.S. Geological Survey, in cooperation with the Federal Highway Administration, began a study to assess the current condition of bridge-scour countermeasures at selected sites to evaluate their effectiveness. Bridge-scour countermeasures were assessed during 2014-2016. Site assessments included reviewing countermeasure design plans, summarizing the peak and daily streamflow history, and assessments at each site. Each site survey included a photo log summary, field form, and topographic and bathymetric geospatial data and metadata. This report documents the study area and site-selection criteria, explains the survey methods used to evaluate the condition of countermeasures, and presents the complete documentation for each countermeasure assessment.

Florida, Illinois, Missouri, Montana↗
USGS2016

Characteristics of lesser prairie-chicken ( Tympanuchus pallidicinctus ) long-distance movements across their distribution

Long-distance movements are important adaptive behaviors that contribute to population, community, and ecosystem connectivity. However, researchers have a poor understanding of the characteristics of long-distance movements for most species. Here, we examined long-distance movements for the lesser prairie-chicken ( Tympanuchus pallidicinctus ), a species of conservation concern. We addressed the following questions: (1) At what distances could populations be connected? (2) What are the characteristics and probability of dispersal movements? (3) Do lesser prairie-chickens display exploratory and round-trip movements? (4) Do the characteristics of long-distance movements vary by site? Movements were examined from populations using satellite GPS transmitters across the entire distribution of the species in New Mexico, Oklahoma, Kansas, and Colorado. Dispersal movements were recorded up to 71 km net displacement, much farther than hitherto recorded. These distances suggest that there may be greater potential connectivity among populations than previously thought. Dispersal movements were displayed primarily by females and had a northerly directional bias. Dispersal probabilities ranged from 0.08 to 0.43 movements per year for both sexes combined, although these movements averaged only 16 km net displacement. Lesser prairie-chickens displayed both exploratory foray loops and round-trip movements. Half of round-trip movements appeared seasonal, suggesting a partial migration in some populations. None of the long-distance movements varied by study site. Data presented here will be important in parameterizing models assessing population viability and informing conservation planning, although further work is needed to identify landscape features that may reduce connectivity among populations.

Colorado, Kansas, Oklahoma, New Mexico, Texas↗
USGS2025

National Park Service staff perspectives on how climate change affects visitor use

1. Many public lands, including those managed by the U.S. National Park Service(NPS), have the purpose of conserving natural and cultural resources and providing opportunities for visitors to recreate in and enjoy these areas. Achieving this mission becomes more challenging as drought, flooding, increasing temperatures and other climatic change effects are impacting NPS lands and visitors and affecting factors such as visitation, recreation access and health and safety among other aspects of park operations. 2. However, the literature lacks insights from staff dealing with on-the-ground climate impacts to visitor use. To address this gap, we held semi-structured interviews with 63 staff from 31 NPS units across the United States (U.S.) to better understand the effects of climate change on visitor use. We qualitatively analysed the interviews using both deductive and inductive methods to identify key themes. 3. Interview participants consistently noted that climate change is already affecting visitor use at their parks. For instance, increasing temperatures are negatively affecting both staff and visitor safety at parks nationwide, whereas all coastal parks within our sample are already experiencing impacts from sea-level rise or more frequent and severe coastal storms and hurricanes. Other impacts include reduced recreational access, damaged infrastructure and cultural resources and diminished visitor experiences due to fire and smoke. 4. Similarly, concerns about future impacts often revolved around the health and safety of visitors and staff—particularly related to wildfire and smoke, water quality and availability, and increased heat—and climate change forever altering parks. 5. Our research shows staff in parks and protected areas are noticing effects of climate change on visitor use; some of these impacts have not been previously documented in the scientific literature. Study results highlight future visitor use management research needs and key topics to consider for visitor use planning processes.

People and Nature↗
USGS2017

Restoration versus invasive species: Bigheaded carps’ use of a rehabilitated backwater

Knowledge of how invasive species use invaded habitats can aid in developing management practices to exclude them. Swan Lake, a 1100-ha Illinois River (USA) backwater, was rehabilitated to restore ecosystem functions, but may provide valuable habitat for invasive bigheaded carps [bighead carp ( Hypophthalmichthys nobilis ) and silver carp ( H . molitrix )]. Use (residency and passages) of Swan Lake by invasive bigheaded carps was monitored using acoustic telemetry ( n = 50 individuals/species) to evaluate the use of a large, restored habitat from 2004 to 2005. Passages (entrances/exits) by bigheaded carps were highest in winter, and residency was highest in the summer. Bighead carp backwater use was associated with the differences in temperature between the main channel and backwater, and passages primarily occurred between 18:00 h and midnight. Silver carp backwater use was positively correlated with water level and main channel discharge, and fewer passages occurred between 12:00 h and 18:00 h than during any other time of day. Harvest occurring during summer or high main channel discharge could reduce backwater abundances while maintenance of low water levels could reduce overall backwater use. Conclusions from this study regarding the timing of bigheaded carps' use of backwater habitats are critical to integrated pest management plans to control invasive species.

River Research and Applications↗
USGS1980

Sediment waves on the Monterey fan levee: a preliminary physical interpretation.

Sediment waves on the deep ocean floor occur mostly on the lower continental rise on slopes of 1° or less. Previous studies show that their amplitude and wavelength vary greatly, but little is known about their shape in plan. A detailed survey of a 30-km 2 area of abyssal-depth sediment waves associated with the levee of the Monterey fan valley shows a pattern of sinuous crests and troughs with parallel, well-bedded internal structure. Material in the upper 1 m of sediment consists predominantly of bioturbated, muddy coccolith ooze. A single thin, silty horizon can be correlated between adjoining waves. On the basis of measured wave dimensions and an estimate of flow velocity we use a simple two-layer model for water movement to infer approximate flow parameters. The sediment waves are considered to be formed most likely by low-velocity (10 cm/s), low-concentration turbidity flows approximately 100–800 m thick. This interpretation emphasizes the role of low-speed, low-concentration turbidity currents in the downslope movement of fine-grained material. This type of transport—deposition regime explains the formation of sediment waves very well except for certain waves occurring on depositional ridges in the deep ocean.

Marine Geology↗
USGS2017

Effects of internal phosphorus loadings and food-web structure on the recovery of a deep lake from eutrophication

We used monitoring data from Lake Lugano (Switzerland and Italy) to assess key ecosystem responses to three decades of nutrient management (1983–2014). We investigated whether reductions in external phosphorus loadings (L ext ) caused declines in lake phosphorus concentrations (P) and phytoplankton biomass (Chl a ), as assumed by the predictive models that underpinned the management plan. Additionally, we examined the hypothesis that deep lakes respond quickly to L ext reductions. During the study period, nutrient management reduced L ext by approximately a half. However, the effects of such reduction on P and Chl a were complex. Far from the scenarios predicted by classic nutrient-management approaches, the responses of P and Chl a did not only reflect changes in L ext , but also variation in internal P loadings (L int ) and food-web structure. In turn, L int varied depending on basin morphometry and climatic effects, whereas food-web structure varied due to apparently stochastic events of colonization and near-extinction of key species. Our results highlight the complexity of the trajectory of deep-lake ecosystems undergoing nutrient management. From an applied standpoint, they also suggest that [ i ] the recovery of warm monomictic lakes may be slower than expected due to the development of L int , and that [ ii ] classic P and Chl a models based on L ext may be useful in nutrient management programs only if their predictions are used as starting points within adaptive frameworks.

Lake Lugano↗
USGS2019

A multidisciplinary coastal vulnerability assessment for local government focused on ecosystems, Santa Barbara area, California

Incorporating coastal ecosystems in climate adaptation planning is needed to maintain the well-being of both natural and human systems. Our vulnerability study uses a multidisciplinary approach to evaluate climate change vulnerability of an urbanized coastal community that could serve as a model approach for communities worldwide, particularly in similar Mediterranean climates. We synthesize projected changes in climate, coastal erosion and flooding, watershed runoff and impacts to two important coastal ecosystems, sandy beaches and coastal salt marshes. Using downscaled climate models along with other regional models, we find that temperature, extreme heat events, and sea level are expected to increase in the future, along with more intense rainfall events, despite a negligible change in annual rainfall. Consequently, more droughts are expected but the magnitude of larger flood events will increase. Associated with the continuing rise of mean sea level, extreme coastal water levels will occur with increasingly greater magnitudes and frequency. Severe flooding will occur for both natural (wetlands, beaches) and built environments (airport, harbor, freeway, and residential areas). Adaptation actions can reduce the impact of rising sea level, which will cause losses of sandy beach zones and salt marsh habitats that support the highest biodiversity in these ecosystems, including regionally rare and endangered species, with substantial impacts occurring by 2050. Providing for inland transgression of coastal habitats, effective sediment management, reduced beach grooming and removal of shoreline armoring are adaptations that would help maintain coastal ecosystems and the beneficial services they provide.

California↗
USGS2024

occupancyTuts: Occupancy modelling tutorials with RPresence

1. The occupancy modelling framework offers tremendous flexibility in estimating species abundance and distribution patterns while accounting for imperfect detection, and has seen rapid growth and adoption since its introduction at the beginning of the century. 2. At the same time, in an era of big data, there are increasing demands on developing quantitative skills and proficiency in young ecologists, many of whom lack the quantitative training needed to conduct research professionally. 3. We introduce occupancyTuts , an R package that features 28 learnr tutorials that teach the statistical underpinnings of several occupancy models. The tutorials include written content, instructional videos, R exercises, and quiz elements, covering a range of topics including statistical underpinnings, single- and dynamic-occupancy models, study design and several of the ‘spin-off’ models that extend the basic framework. 4. We plan for development of new tutorials that use RPresence as the analysis engine, and welcome new tutorial contributions that use other R packages as the analysis engine as well.

Methods in Ecology and Evolution↗
USGS2001

Tampa Bay Integrated Science Pilot Study: wetland characterization

Coastal wetlands in Tampa Bay consist of mangrove forest and tidal salt marsh. Wetlands buffer storm surges, provide fish and wildlife habitat, and enhance water quality through the removal of water-borne nutrients and contaminants. Substantial areas of both mangrove and salt marsh have been lost to agricultural, residential and industrial development in this urban estuary. Wetlands restoration has been initiated in Tampa Bay. Baseline studies on the current condition of wetlands and historical and prehistorical information is needed for successful restoration planning and evaluation. A major objective of this component of the Tampa Bay pilot program was to characterize wetlands in Tampa Bay beginning with areas that differ in their degree of human-induced disturbance ( Fig. 1 ). The Alafia River area is urbanized, industrialized and dredged, whereas the Terra Ceia area has a history of agricultural use with associated soil berms and mosquito ditches, but has not been farmed for at least 20 years ( Fig. 2 ).

Open-File Report↗
USGS2002

Southwest Washington coastal erosion workshop report 2000

This report is a compilation of abstracts that correspond to oral presentations and posters presented at the fifth principal investigators workshop of the Southwest Washington Coastal Erosion Study. The workshop was held November 15 - 17, 2000 at the Department of Ecology headquarters building in Olympia, WA. For the fourth consecutive year in November, the workshop convened the entire multi-disciplinary group of scientists and engineers working on the Study or on related projects within the Columbia River littoral cell (CRLC) (Figures 1 and 2). The workshop participants are listed in the List of Attendees section towards the end of this report. The purpose of this workshop was to bring all Study investigators and associated engineers and scientists together to discuss recent work, ongoing tasks, and future research plans in the CRLC. Investigators were asked to present recent data, preliminary interpretations, and research results to invoke discussion and correlation with parallel scientific efforts. The abstracts compiled in this report represent a wealth of information on the CRLC, but because much of the work is in progress, the reader is advised that the information provided herein is preliminary and subject to change.

Oregon;Washington↗
USGS1982

Gulf of Alaska and Lower Cook Inlet summary report 3: Second revision of Outer Continental Shelf oil and gas activities in the Gulf of Alaska (including Lower Cook Inlet) and their onshore impacts: A summary report, September 1980

Five Outer Continental Shelf (OCS) lease sales have been held in the Gulf of Alaska subregion of Alaska. Lease Sale 39, in the northern Gulf of Alaska, was held on April 13, 1976, and it resulted in the leasing of 76 tracts. Lease Sale CI, held on October 27, 1977, resulted in the leasing of 87 tracts in Lower Cook Inlet. Lease Sale 55 in the eastern Gulf of Alaska, held on October 21, 1980, leased 35 tracts. The first Reoffering Sale (RS-1), held on June 30, 1981, resulted in the leasing of one tract in the eastern Gulf of Alaska. Lease Sale 60, the most recent sale in the subregion, was held on September 29, 1981. It resulted in the leasing of 13 tracts in the Lower Cook Inlet and the Shelikof Strait. Exploratory drilling has been conducted on tracts leased in Lease Sales 39 and CI. No commercial discoveries were made, and no further exploratory drilling is anticipated on tracts leased in either sale. ARCO has plans to explore a tract leased in Lease Sale 55 in January 1983. Chevron has conducted geohazard studies on tracts leased in Lease Sale 60. The results of these studies will determine if exploratory wells will be drilled. Exploratory drilling, if it does take place, is not anticipated before the summer of 1983. In March 1982, the Department of the Interior prepared new resource estimates for the Gulf of Alaska subregion. The risked mean resource estimates for tracts leased in Lease Sale 55 and Lease Sale RS-1 are 12.1 million barrels of oil and 46.2 billion cubic feet of gas. The risked mean resource estimates for tracts leased in Lease Sale 60 are 5.6 million barrels of oil and 5 billion cubic feet of gas. The onshore impacts from previous OCS exploration in the Gulf of Alaska and the Lower Cook Inlet were minimal. Yakutat will be used to support exploratory drilling on any Lease Sale 55 or Lease Sale RS-1 tracts. If exploratory drilling takes place on Lease Sale 60 tracts, support facilities are expected to be located in Kenai or on Kodiak Island.

Gulf of Alaska, Outer Continental Shelf↗
USGS2008

Aquifer Tests and Characterization of Transmissivity, Ada-Vamoosa Aquifer on the Osage Reservation, Osage County, Oklahoma, 2006

The Ada-Vamoosa aquifer of northeastern Oklahoma is a sedimentary bedrock aquifer of Pennsylvanian age that crops out over 800 square miles of the Osage Reservation. The Osage Nation needed additional information regarding the production potential of the aquifer to aid them in future development planning. To address this need, the U.S. Geological Survey, in cooperation with the Osage Nation, conducted a study of aquifer properties in the Ada-Vamoosa aquifer. This report presents the results of the aquifer tests from 20 wells in the Ada-Vamoosa aquifer and one well in a minor aquifer east of the Ada-Vamoosa outcrop on the Osage Reservation. Well information for 17 of the 21 wells in this report was obtained from the Indian Health Service. Data collected by the U.S. Geological Survey during this investigation are pumping well data from four domestic wells collected during the summer of 2006. Transmissivity values were calculated from well pumping data or were estimated from specific capacity values depending on the reliability of the data. The estimated transmissivity values are 1.1 to 4.3 times greater than the calculated transmissivity values. The calculated and estimated transmissivity values range from 5 to 1,000 feet squared per day.

Scientific Investigations Report↗
USGS2009

Trends in Surface-Water Quality at Selected Ambient-Monitoring Network Stations in Kentucky, 1979-2004

Increasingly complex water-management decisions require water-quality monitoring programs that provide data for multiple purposes, including trend analyses, to detect improvement or deterioration in water quality with time. Understanding surface-water-quality trends assists resource managers in identifying emerging water-quality concerns, planning remediation efforts, and evaluating the effectiveness of the remediation. This report presents the results of a study conducted by the U.S. Geological Survey, in cooperation with the Kentucky Energy and Environment Cabinet-Kentucky Division of Water, to analyze and summarize long-term water-quality trends of selected properties and water-quality constituents in selected streams in Kentucky's ambient stream water-quality monitoring network. Trends in surface-water quality for 15 properties and water-quality constituents were analyzed at 37 stations with drainage basins ranging in size from 62 to 6,431 square miles. Analyses of selected physical properties (temperature, specific conductance, pH, dissolved oxygen, hardness, and suspended solids), for major ions (chloride and sulfate), for selected metals (iron and manganese), for nutrients (total phosphorus, total nitrogen, total Kjeldahl nitrogen, nitrite plus nitrate), and for fecal coliform were compiled from the Commonwealth's ambient water-quality monitoring network. Trend analyses were completed using the S-Plus statistical software program S-Estimate Trend (S-ESTREND), which detects trends in water-quality data. The trend-detection techniques supplied by this software include the Seasonal Kendall nonparametric methods for use with uncensored data or data censored with only one reporting limit and the Tobit-regression parametric method for use with data censored with multiple reporting limits. One of these tests was selected for each property and water-quality constituent and applied to all station records so that results of the trend procedure could be compared among stations. Flow-adjustment procedures were used with these techniques at all stations to remove the effects of streamflow on water-quality variability. Flow adjustments were used for all constituents, except temperature. A decreasing trend indicates a decrease in concentration of a particular constituent; whereas, an increasing trend indicates an increase in concentration and potential degradation in water quality. Trend results varied statewide by station and by physical property and water-quality constituent. The results for all stations and all physical properties and water-quality constituents examined had at least one statistically significant (p-value <0.05) increasing or decreasing trend during the specified period of record. Water temperature and concentrations of dissolved oxygen had no significant decreasing trends at any station. Water temperature had one significant increasing trend at the South Fork Cumberland River near Blue Heron station. Specific conductance and concentrations of hardness had one significant decreasing trend at the South Fork Cumberland River near Blue Heron station. pH also had a significant decreasing trend at the Mud River near Gus station. Concentrations of total suspended solids had 1 increasing trend at the Kentucky River at High Bridge station and 10 decreasing trends with 5 of those stations located in the Cumberland River Basin. Major ions analyzed for trends included chloride and sulfate. Concentrations of chloride at the 37 stations had increasing trends at 15 stations, decreasing trends at 3 stations, and no significant trend in concentration over time at 19 stations. Most of the increasing trends in concentrations of chloride are located in the northern part of Kentucky, possibly indicating an increase in the use of road salts for road deicing and (or) the result of resource extraction (oil, gas, and coal). Increasing trends of sulfate concentrations were detected at seven stations, all located in the Appalachian

Scientific Investigations Report↗