Habitat destruction and alteration. Historical trends and future prospects for amphibians
Abstract not supplied at this time
Book chapter↗
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Results for “Trends”
Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.
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Human disruption of element interactions: Drivers, consequences, and trends for the twenty-first century
No abstract available.
SCOPE (Scientific Committee on Problems of the Env↗
Long-term ecological trend monitoring at Marine Corps Base, Camp Pendleton: Bird community study, 1994
No abstract available at this time
Report↗
Biomonitoring of Environmental Status and Trends (BEST) Program: Environmental contaminants and their effects on fish in the Mississippi River Basin
We collected, examined, and analyzed 1378 fish of 22 species from 47 sites in the Mississippi River basin (MRB) during 1995 and from a reference site in 1996. The sampling sites in the MRB represented National Contaminant Biomonitoring Program (NCBP) stations situated at key points on major rivers and National Water- Quality Assessment Program (NAWQA) stations located on lower-order rivers and streams in the Eastern Iowa Basins (EIB) and Mississippi Embayment (MSE) Study Units. The reference site was the water supply system of the USGS-Leetown Science Center in rural Jefferson County, WV. Common carp (Cyprinus carpio; carp) and black basses (Micropterus spp.; bass), the targeted species, together represented 82% of the fish collected. Each fish was examined in the field for externally and internally visible gross lesions, selected organs were weighed to compute various ponderal and organo-somatic indices, and selected tissues and fluids were obtained and preserved for analysis of biomarkers. Fish health indicators included splenic macrophage aggregates, lysozyme activity, and hispathological analysis of liver, kidney, and other tissues. Reproductive biomarkers included analysis of plasma concentrations of vitellogenin (vtg) and the sex steroid hormones 17-estradiol (E2) and 11-ketotestosterone (11- kt); and the histological determination of percent oocyte atresia (in female fish) and gonadal stage. Hepatic ethoxyresorufin O-deethylase (EROD) activity was also measured. Composite samples of whole fish from each station were grouped by species and gender and analyzed for persistent organochlorine and elemental contaminants and for dioxin-like activity (TCDD-EQ) using the H4IIE rat hepatoma cell bioassay. Organochlorine and inorganic contaminant concentrations in fish were generally low relative to historical levels at most sites, but remained present at concentrations representing threats to piscivorous wildlife in some locations. Toxaphene and DDT (mostly as p,p?-DDE) concentrations remained elevated in fish from the cottongrowing regions of the lower Mississippi valley, and were generally greater in the smaller streams draining agricultural areas (that is, in the MSE Study Unit) than at large river sites. Cyclodiene pesticide concentrations were also greatest in the EIB Study Unit and elsewhere in the corn-growing regions of the mid-MRB. Former point-sources of organochlorine pesticides also remained evident, especially in the Mississippi River near Memphis, TN. Consistent with previous findings, total PCB concentrations tended to be greatest (1-3 g/g) in the industrialized and urbanized Ohio River and Upper Mississippi sub-basins and at Memphis, TN, and were generally correlated with TCDD-EQ and EROD activity. Conversely, PCB concentrations were low (<0.1 g/g) in the more agricultural parts of the MRB. Concentrations of inorganic contaminants were also relatively low and stable or declining relative to past levels at most sites. Exceptions were Hg and Se; Hg concentrations were slightly elevated (>0.3 g/g) in bass from the Mississippi River at Memphis and several other sites and in carp from one MSE site. Concentrations of Se were also great enough to constitute a hazard to piscivorous wildlife (>0.6 g/g) at several MRB sites in the western parts of the MRB and were especially high (4-5 g/g) in fish from John Martin Reservoir, CO, where elevated concentrations were reported previously. Biomarker results indicated that fish from many stations had been exposed to contaminants, but at no sites did findings indicate exposure to high concentrations of toxic chemicals. Noteworthy among biomarker findings was that 73% of the male smallmouth bass (Micropterus dolomieui) from the Mississippi River at Lake City, MN (Lake Pepin) were intersex as indicated by the histological detection of ovotestes; and the combined EROD and H4IIE results indicated that fish from several rural sites in the
Mississippi River basin↗
Mississippi/Alabama pinnacle trend ecosystem monitoring Final Synthesis Report
This Final Synthesis Report summarizes a four-year program to characterize and monitor carbonate mounds on the Mississippi/Alabama outer continental shelf (OCS). The study area is shown in Fig.ES.1. The study was conducted by Continental Shelf Associates, Inc. and the Geochemical and Environmental Research Group (GERG) of Texas A&M University (TAMU), for the U.S. Geological Survey (USGS), Biological Resources Division.
Biological Science Report↗
Biomonitoring of Environmental Status and Trends (BEST) Program: Field Procedures for Assessing the Exposure of Fish to Environmental Contaminants
This document describes procedures used to collect information, tissues, and fluids for documenting the exposure of fish to environmental contaminants. For the procedures described here, fish are captured (preferably by electrofishing) and held alive until processing (generally <1 h). Fish are weighed, measured, and examined for grossly visible external lesions and pathologies. A blood sample is collected by caudal veinipuncture using a needle and syringe. The fish is subdued and it's abdominal cavity opened. The internal organs are dissected from the fish for examination. The sex of the fish is determined by direct observation of its gonads. The liver is weighed (most species) and cut into small cubes and flash-frozen in cryogenic vials, which are stored and shipped in dry ice or liquid nitrogen. Additional liver cubes plus all grossly visible anomalies are preserved for histopathology. The gonads and spleen are weighed, and samples are preserved for histopathology. The kidneys are examined, and histopathology samples collected. A gill sample is also collected and preserved. All remaining tissues are returned to the carcass, which is wrapped in foil, labeled for chemical analysis, and chilled. Individual fish carcasses are composited by station, species, and gender; frozen; and shipped to the analytical laboratory. Procedures are also described for record keeping; processing blood to obtain serum and plasma; flash-freezing samples; cleaning equipment; and preventing the transport of living organisms among waterways. A list of necessary equipment and supplies is also provided.
Information and Technology Report↗
Aerial surveys of waterbirds in Alaska 1957-94 : population trends and observer variability
Explore the source record for details and available documents.
Information and Technology Report↗
Population trends of blackbirds and starlings in North America, 1966-76
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Special Scientific Report - Wildlife↗
Hunting and harvest trends for migratory game birds other than waterfowl: 1964-76
No abstract available.
Special Scientific Report - Wildlife↗
Population trends, growth, and movement of bigmouth buffalo, Ictiobus cyprinellus, in Lake Oahe, 1963-70
The bigmouth buffalo, Ictiobus cyprinellus, is the most important commercial species in Lake Oahe, a reservoir in the upper Missouri River. The population was dominated by three strong year classes (1959, 1960, and 1962). Estimated population in the fall of 1964 was 540,000 fish of the combined 1959-60 year classes and 5 million of the 1962 year class (equivalent to 81 kg per hectare). Abundance declined irregularly during 1964-70. Annual landings of these two dominant groups during 1965-70 ranged from 149 to 271 metric tons. The total landings during the period amounted to about 151,800 fish of the 1959-60 year classes and 313,000 fish of the 1962 year class. Growth rate was high during the first few years of impoundment and then declined. Males and females grew at about the same rate for the first 4 yr of life, but females were longer and heavier than males at ages V-VIII. At these ages, fish of the 1962 year class were about 10% shorter and 36% lighter than those of the 1959 year class. Growth of tagged and untagged fish was similar. The number of females per male increased with age. Age at maturity increased slightly as growth rate declined. Movement of marked fish was extensive and the recapture of marked fish was directly related to size of fish, location of release, and subsequent fishing pressure; 44% were recaptured downstream from the point of release, and 38% upstream. Females showed a stronger tendency to move downstream than males. Maximum distance traveled was 380 km and maximum rate of travel was 6.4 km per day. Successful reproduction appeared to be associated with flooding of shoreline vegetation during spring and early summer. Inasmuch as little such flooding is expected in the future, annual landings of bigmouth buffalo will probably continue to decline sharply.
Technical Paper↗
Groundwater quality data in 15 GAMA study units: results from the 2006–10 Initial sampling and the 2009–13 resampling of wells, California GAMA Priority Basin Project
The Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) program was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). From May 2004 to March 2012, the GAMA-PBP collected samples from more than 2,300 wells in 35 study units across the State. Selected wells in each study unit were sampled again approximately 3 years after initial sampling as part of an assessment of temporal trends in water quality by the GAMA-PBP. This triennial (every 3 years) trend sampling of GAMA-PBP study units concluded in December 2013. Fifteen of the study units, initially sampled between January 2006 and June 2010 and sampled a second time between April 2009 and April 2013 to assess temporal trends, are the subject of this report. The initial sampling was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies in the 15 study units. In these study units, 730 wells were selected by using a spatially distributed, randomized grid-based method to provide statistical representation of the areas assessed (grid wells, also called “status wells”). Approximately 3 years after the initial sampling, 93 of the previously sampled status wells (approximately 10 percent in each study unit) were randomly selected for trend sampling (“trend wells”). The 15 study units sampled for trends were distributed among 4 hydrogeologic provinces: Central Valley, Basin and Range, Desert, and Transverse and selected Peninsular Ranges. The total number of status wells sampled, along with those sampled again for trends, varied by study unit. In the Central Valley hydrogeologic province, the numbers of status wells and trend wells in each study unit were as follows: Kern County subbasin study unit—47 status wells, 5 trend wells Central Eastside San Joaquin Basin study unit—58 status wells, 6 trend wells Middle Sacramento Valley study unit—71 status wells, 8 trend wells Northern Sacramento Valley study unit—43 status wells, 4 trend wells Madera–Chowchilla study unit—30 status wells, 4 trend wells Western San Joaquin Valley study unit—39 status wells, 4 trend wells. The Basin and Range hydrogeologic province had only one study unit: Owens and Indian Wells Valleys study unit—53 status wells, 6 trend wells. In the Desert hydrogeologic province, the numbers of wells were as follows: Coachella Valley study unit—19 status wells 4 trend wells Colorado River study unit—20 status wells, 3 trend wells Antelope Valley study unit—56 status wells, 6 trend wells Mojave study unit—52 status wells, 7 trend wells Borrego Valley, Central Desert and Low-Use Basins of the Mojave and Sonoran Deserts study unit—49 status wells, 6 trend wells. In the Transverse and Selected Peninsular Ranges hydrogeologic province, the numbers of wells were as follows: Coastal Los Angeles Basin study unit—61 status wells, 8 trend wells Upper Santa Ana Watershed study unit—90 status wells, 16 trend wells Santa Clara River Valley study unit—42 status wells, 6 trend wells. The groundwater samples were analyzed for a number of synthetic organic constituents (volatile organic compounds, pesticides, and pesticide degradates), constituents of special interest (perchlorate, N -nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), and naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements). Naturally occurring isotopes (tritium, carbon-14, and stable isotopes of hydrogen and oxygen in water) also were measured to help identify processes affecting groundwater quality and the sources and ages of the sampled groundwater. More than 200 constituents and water-quality indicators were investigated. Quality-control samples (blanks, replicates, or samples for matrix spikes) were collected at 34 percent of the trend wells, and the results for these samples were used to evaluate the quality of the data for the groundwater samples. On the basis of detections in laboratory and field blanks in samples from GAMA-PBP study units, including the study units presented here, some groundwater results were adjusted in this report. Differences between replicate samples were mostly within acceptable ranges, indicating acceptably low variability in analytical results. Median matrix-spike recoveries were within the acceptable range (70 to 130 percent) for 189 of the 224 compounds for which matrix spikes were analyzed (84 percent). This study did not attempt to evaluate the quality of water delivered to consumers. After withdrawal, groundwater used for drinking water typically is treated, disinfected, and blended with other waters to attain acceptable water quality. The benchmarks used in this report apply to treated water that is served to the consumer, not to untreated groundwater. To provide some context for the results, however, concentrations of constituents measured in these groundwater samples were compared with benchmarks established by the U.S. Environmental Protection Agency and California Department of Public Health. Comparisons between data collected for this study and benchmarks for drinking-water quality are for illustrative purposes only and are not indicative of compliance or non-compliance with those benchmarks. Most constituents that were detected in groundwater samples from the trend wells were found at concentrations less than drinking-water benchmarks. Two volatile organic compounds (VOCs)—tetrachloroethene and trichloroethene—were detected in samples from one or more wells at concentrations greater than their health-based benchmarks, and three VOCs—chloroform, tetrachloroethene, and trichloroethene—were detected in at least 10 percent of the trend-well samples from the initial sampling period and the later trend sampling period. No pesticides were detected at concentrations near or greater than their health-based benchmarks. Three pesticide constituents—atrazine, deethylatrazine, and simazine—were detected in more than 10 percent of the trend-well samples in both sampling periods. Perchlorate, a constituent of special interest, was detected at a concentration greater than its health-based benchmark in samples from one trend well in the initial sampling and trend sampling periods, and in an additional trend well sample only in the trend sampling period. Most detections of nutrients, major and minor ions, and trace elements in samples from trend wells were less than health-based benchmarks in both sampling periods. Exceptions included nitrate, fluoride, arsenic, boron, molybdenum, strontium, and uranium; these were all detected at concentrations greater than their health-based benchmarks in at least one well sample in both sampling periods. Lead and vanadium were detected above their health-based benchmarks in one sample each collected in the initial sampling period only. The isotopic ratios of oxygen and hydrogen in water and the activities of tritium and carbon-14 generally changed little between sampling periods.
California↗
Climate and streamflow characteristics for selected streamgages in eastern South Dakota, water years 1945–2013
Upward trends in precipitation and streamflow have been observed in the northeastern Missouri River Basin during the past century, including the area of eastern South Dakota. Some of the identified upward trends were anomalously large relative to surrounding parts of the northern Great Plains. Forcing factors for streamflow trends in eastern South Dakota are not well understood, and it is not known whether streamflow trends are driven primarily by climatic changes or various land-use changes. Understanding the effects that climate (specifically precipitation and temperature) has on streamflow characteristics within a region will help to better understand additional factors such as land-use alterations that may affect the hydrology of the region. To aid in this understanding, a study was completed by the U.S. Geological Survey, in cooperation with the East Dakota Water Development District and James River Water Development District, to assess trends in climate and streamflow characteristics at 10 selected streamgages in eastern South Dakota for water years (WYs) 1945–2013 (69 years) and WYs 1980–2013 (34 years). A WY is the 12-month period, October 1 through September 30, and is designated by the calendar year in which it ends. One streamgage is on the Whetstone River, a tributary to the Minnesota River, and the other streamgages are in the James, Big Sioux, and Vermillion River Basins. The watersheds for two of the James River streamgages extend into North Dakota, and parts of the watersheds for two of the Big Sioux River streamgages extend into Minnesota and Iowa. The objectives of this study were to document trends in streamflow and precipitation in these watersheds, and characterize the residual streamflow variability that might be attributed to factors other than precipitation. Residuals were computed as the departure from a locally-weighted scatterplot smoothing (LOWESS) model. Significance of trends was based on the Mann-Kendall nonparametric test at a 0.10 significance level. Of the 10 streamgages selected, only the Elm River at Westport (in the upper part of James River Basin) did not have a significant upward trend in annual mean streamflow for WYs 1945–2013, whereas only one-half of the streamgages had significant upward trends in annual mean streamflow for WYs 1980–2013. Mean and 7-day minimum streamflows also had upward trends for the spring runoff period (March–May) for most of the streamgages during WYs 1945–2013 and for one streamgage during WYs 1980–2013. Magnitudes of increases in streamflow were as great as 30 cubic feet per second per year for the streamgage on the James River near Scotland during WYs 1980–2013. Precipitation trends for WYs 1945–2013 were not necessarily significant for the watersheds of streamgages with a significant streamflow trend. Annual total precipitation had a significant upward trend for the watersheds of 4 of the 10 streamgages during WYs 1945–2013 and no significant trends for WYs 1980–2013. The most widespread precipitation increase was for September–November, with significant upward trends for the watersheds of 8 of the 10 streamgages during WYs 1945–2013; however, no trends in September– November precipitation were significant for WYs 1980–2013. The greatest magnitude of increase in precipitation was for the December–May season during WYs 1980–2013, which had a mean increase of 0.106 inch per year in the watersheds of streamgages with significant trends. The correlation between streamflow and precipitation metrics was low as indicated by the mean coefficient of determination (R 2 ) of 0.18 for all pairs considered. The highest locally-weighed scatterplot smoothing (LOWESS) correlation was between annual precipitation (by water year) and annual mean streamflow (by water year), which had a mean R 2 of 0.47 for all streamgages and was as high as 0.72 for one streamgage. The correlation between annual precipitation and March–May mean streamflow had a mean R 2 of 0.33 for all streamgages and was as high as 0.52 for one streamgage. Other metrics had R 2 values for LOWESS correlations that were less than 0.3 and were not further considered for analyses of residuals. For annual precipitation as a predictor of annual mean flow, precipitation-removed streamflow had significant upward trends during WYs 1945–2013 for one-half of the streamgages. Upward trends in residual annual mean streamflow were indicated for the Whetstone River and lower part of the Big Sioux River Basin, indicating that other factors are contributors to streamflow variability during WYs 1945–2013. In contrast, most of the streamgages in the James and Vermillion River Basins had no trends in residual annual mean streamflow, indicating that streamflow trends can be explained primarily by precipitation. Precipitation-removed streamflow had fewer trends during the more recent analysis period of WYs 1980–2013 than WYs 1945–2013 for all streamgages in eastern South Dakota. Upward trends in residuals for March– May mean streamflow were indicated for Skunk Creek at Sioux Falls and the Big Sioux River at Akron, but trends in residuals were not significant at the remaining streamgages. For the streamgages with significant trends in residual streamflow (such as the streamgage on the Whetstone River and streamgages in the Big Sioux River Basin), land-use changes likely are minor factors, with the main factors probably being changes in the timing and frequency of large precipitation events and persistently wetter antecedent conditions. Changes in the relation between precipitation and streamflow since 1945 were evident when considering the runoff efficiency of the watershed. For example, the streamflow response to annual precipitation of 25 inches for the James River near Scotland increased from approximately 1,000 cubic feet per second for WYs 1945–1990 to about 2,500 cubic feet per second for WYs 1991–2013. The importance of antecedent conditions on annual mean streamflow also was indicated by the significance of the multiple linear regression coefficients of annual mean streamflow and precipitation from preceding water years for all but one streamgage. In addition, rising groundwater levels are present in wells in eastern South Dakota, particularly since the 1980s.
South Dakota↗
Characterization of factors affecting groundwater levels in and near the former Lake Traverse Indian Reservation, South Dakota, water years 1956–2017
The U.S. Geological Survey (USGS), in cooperation with the Sisseton Wahpeton Oyate, completed a study to characterize water-level fluctuations in observation wells relative to driving factors that affect water levels in and near the historical 1867 boundary of the Lake Traverse Indian Reservation. The study investigated concerns regarding potential effects of groundwater withdrawals and climate conditions on groundwater levels within an area that includes the historical boundary of the reservation and a surrounding area that extends 10 miles in all directions within South Dakota. Characterization of water-level fluctuations in observation wells and relative driving factors was accomplished by statistical trend analysis. Monthly data from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) were aggregated to obtain annual and seasonal datasets for total precipitation, minimum air temperature ( T min ), and maximum air temperature ( T max ) for the study area and a surrounding buffer area. Trend tests for gridded data for total precipitation, T min , and T max were completed for annual and seasonal time series for water years 1956–2017, which is about 2 years before the earliest available water-level measurements. A 2-year offset was arbitrarily selected because scrutiny of water-level and precipitation data indicated that responses of groundwater levels for many of the observation wells lagged major changes in precipitation patterns by about 2 years. Statistically significant upward trends were detected for annual precipitation and annual T min for most of the study area and the surrounding buffer area. Statistically significant downward trends in T max were detected for only a few 2.5 arc-minute grid cells; however, the sparsity of the spatial coverage reduces confidence that these are true trends, in contrast to the near completeness of the spatial coverage in upward trends for T min . Spatial distributions of statistically significant trends in seasonal climate data were generally similar to the annual trends, but with substantial differences in the spatial density of the trends. Potential interactions among water levels in observation wells and streamflow were examined through correlation analyses of the annual median water level for each of 76 observation wells versus the annual mean streamflow for each of four area streamgages. Potential interactions among water levels in observation wells and lake levels were examined through correlation analyses involving 25 area lakes. Resulting correlation coefficients were used as part of an approach for selecting a lake to be plotted in conjunction with water-level and precipitation data for each observation well. Groundwater trends for 76 observation wells were analyzed for three separate water-level parameters (minimum, median, and maximum) because wells are measured sporadically, and data are biased towards more frequent measurements during periods of heaviest irrigation demand. Trends in the time series of annual precipitation (from PRISM) starting 2 years earlier than the associated water-level trend also were analyzed for the location of each individual observation well. Sen’s slope and Mann-Kendall p -values were computed for the three water-level parameters and for the annual precipitation time series. Graphs showing results of trend analyses for each observation well also showed changes with time in the sum of licensed groundwater withdrawals within six specified radii (0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 miles) of each well as a qualitative indicator of proximal groundwater demand. Trends in groundwater levels in observation wells in the study area are predominantly upward, with 43 of 76 wells having significant upward trends for at least one of the three water-level parameters and only 8 wells having significant downward trends for at least one water-level parameter. The upward groundwater trends are driven by predominantly upward precipitation trends, with 43 wells (not all the same wells) also having significant upward trends and no wells having significant downward trends. Significant upward precipitation trends were detected for only two of the eight wells with significant downward groundwater trends. Groundwater levels in some observation wells likely are also substantially affected by interactions with surface water, especially with lakes. Water levels in many area lakes increased in response to wet conditions of the early 1990s and have maintained high water levels ever since. It is recognized that in many cases lakes that were selected for plotting with groundwater hydrographs likely are not hydraulically connected with a groundwater system or aquifer associated with an individual well; however, interactions also are plausible for numerous other lakes for which water-level records are not available.
South Dakota↗
Assessment of surface-water quantity and quality, Eagle River watershed, Colorado, 1947-2007
From the early mining days to the current tourism-based economy, the Eagle River watershed (ERW) in central Colorado has undergone a sequence of land-use changes that has affected the hydrology, habitat, and water quality of the area. In 2000, the USGS, in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, City of Colorado Springs, Colorado Springs Utilities, and Denver Water, initiated a retrospective analysis of surface-water quantity and quality in the ERW. Surface-water quantity data and surface-water quality data were obtained from local, State, and Federal agencies to assist in the analysis of surface-water conditions in the ERW 1947-2007. Surface-water-quality data from 293 sites and 12 different source agencies were compiled into 192 unique sites located on streams and rivers in the ERW. Approximately 39 percent of the unique sites had fewer than 5 samples; while 23 percent of the sites had more than 100 samples. Physical properties were the most abundant type of samples collected, with major ions, nutrients, and trace elements also commonly collected. For selected water-quality properties and constituents in the watershed, this report: (1) characterizes available water quantity and water-quality data, (2) identifies spatial and seasonal variability in water quantity and water quality, (3) provides comparisons to Federal and State water-quality standards or recommendations, (4) characterizes temporal changes in water quality, and (5) where possible, identifies potential causes of these changes. This report provides reconnaissance-level statistical summaries and comparisons of water-quality conditions and characteristics using available data within the ERW. The report also includes streamflow statistics such as: mean annual runoff totals, peak-flood-frequency recurrence intervals, and minimum 7-day mean streamflows for selected sites within the watershed. The spatial patterns for concentrations of trace metals (aluminum, cadmium, copper, iron, manganese, and zinc) indicate an increase in dissolved concentrations of these metals near historical mining areas in the Eagle River and several tributaries near Belden. In general, concentrations decrease downstream from mining areas. Concentrations typically are near or below reporting limits in Gore Creek and other tributaries within the watershed. Concentrations for trace elements (arsenic, selenium, and uranium) in the watershed usually are below the reporting limit, and no prevailing spatial patterns were observed in the data. Step-trend analysis and temporal-trend analysis provide evidence that remediation of historical mining areas in the upper Eagle River have led to observed decreases in metals concentrations in many surface-waters. Comparison of pre- and post-remediation concentrations for many metals indicates significant decreases in metals concentrations for cadmium, manganese, and zinc at sites downstream from the Eagle Mine Superfund Site. Some sites show order of magnitude reductions in median concentrations between these two periods. Evaluation of monotonic trends for dissolved metals concentrations show downward trends at numerous sites in, and downstream from, historic mining areas. The spatial pattern of nutrients shows lower concentrations on many tributaries and on the Eagle River upstream from Red Cliff with increases in nutrients downstream of major urban areas. Seasonal variations show that for many nutrient species, concentrations tend to be lowest May-June and highest January-March. The gradual changes in concentrations between seasons may be related to dilution effects from increases and decreases in streamflow. Upward trends in nutrients between the towns of Gypsum and Avon were detected for nitrate, orthophosphate, and total phosphorus. An upward trend in nitrite was detected in Gore Creek. No trends were detected in un-ionized ammonia within the ERW. Exceedances of State water-quality standards (nitrite, nitrate, and un-ionized ammonia) and levels higher than U.S. Environmental Protection Agency recommendations (total phosphorus) occur in several areas within the ERW. The majority of the exceedances are from comparisons to the U.S. Environmental Protection Agency total phosphorus recommendations. A positive correlation was observed between suspended sediment and total phosphorus. An upward trend in total dissolved solids in Gore Creek may be the result of increases in chloride salts. Highly significant trends were detected in sodium, potassium, and chloride with a significant upward trend in magnesium and a weakly significant upward trend in calcium. A quantitative analysis of the relative abundance of calcium, magnesium, sodium, and potassium to the available anions suggests that chloride salts likely are the source for the detected upward trends because chloride is the only commonly occurring anion with a trend in Gore Greek. A potential source for the observed chloride salts may be the chemical anti-icing and deicing products used during winter road maintenance in municipal areas and on Interstate-70. A downward trend in dissolved solids in the Eagle River between Gypsum and Avon may be contributing to the detected trend on the Eagle River at Gypsum. Significant downward trends were detected in specific ions such as calcium, magnesium, sulfate, and silica. Measures of total dissolved solids as well as comparisons to specific ions show that in water-quality samples within the ERW concentrations generally are lower in the headwaters, with increases downstream from Wolcott. Differences in concentrations likely result from increased abundance of salt-bearing geologic units downstream from Avon. Few sites had measured concentrations that exceeded the State standards for chloride.
Scientific Investigations Report↗
Elk monitoring in Lewis and Clark National Historical Park: 2008-2012 synthesis report
Maintaining elk (Cervus elaphus roosevelti) herds that frequent Lewis and Clark National Historical Park (NHP) is central to the park’s purpose of preserving the historic, cultural, scenic, and natural resources associated with the winter encampment of the Lewis and Clark expedition. Elk were critically important to the Lewis and Clark expedition in providing food and hides that sustained the expedition during the winter of 1805-06 and supplied them for their return east during 1806. Today, elk remain a key component of interpreting the Lewis and Clark story to over 200,000 park visitors each year at the Fort Clatsop visitor center. In 2008, the US Geological Survey (USGS) began collaborating with Lewis and Clark NHP and the NPS North Coast and Cascades Network to develop a protocol for monitoring long-term changes in the magnitude and spatial patterns of elk use within and adjacent to Lewis and Clark NHP (Griffin et al. 2011). Specific objectives of the monitoring program were to measure trends in (1) relative use of the Fort Clatsop unit by elk during winter; (2) the proportion of areas where elk sign is present in the Fort Clatsop unit in winter; and (3) the frequency of elk sightings from roads in and around the Fort Clatsop unit. This report synthesizes the results of the first four years of monitoring elk distribution and use in Lewis and Clark NHP from 2008-2012. We also present data from FY2012 (Appendix 1), in lieu of an annual report for that year. We used fecal pellet group surveys as the cornerstone for monitoring trends in both relative use of the Fort Clatsop Unit by elk and the proportion of areas where elk sign was present at the end of winter. We estimated pellet group density based on data collected from a network of fecal pellet plots distributed systematically throughout the unit. We developed a double observer sampling scheme that enabled us to estimate detection biases and improve the accuracy of pellet group density estimates. We computed the estimated detection probability for any pellet group observed; this probability was a function of the pellet group size and stage of decay, as well as lighting and vegetation conditions, and the number of observers (one or two) searching for pellets in that subplot. We then used these estimated detection probabilities to adjust the raw counts of the detected pellet groups to account for groups that likely went undetected under similar pellet and environmental conditions (each observed pellet group was weighted by the inverse of its estimated detection probability). We also used results from the late winter fecal pellet surveys to quantify the proportion of areas where elk pellets occurred (PAO), which was based on the presence of fecal pellet groups and estimation of detection biases (i.e., accounting for pellet groups that likely went undetected by both observers). In this synthesis, we report temporal trends in both pellet group density and PAO from 2008-2012, based on weighted linear regression analyses as well as spatial variation of pellet group densities over time. We completed late winter fecal pellet surveys at 61-66 plots annually, depending on yearly variation in access. We cleared fecal pellets at survey points in late October / early November each year and returned in late February / early March to count pellet groups left by elk over the winter. The estimated probability that a pellet group was detected by any one observer during late winter was affected most by the pellet group size and was less affected by decay class and lighting conditions. Per-observer detection probabilities ranged from as low as ~10-15% for single pellets to ~85-90% for pellet groups with 50 pellets. Average pellet group density in the Fort Clatsop unit ranged annually from 0.58 (+/- 1.43 standard error [SE]) to 0.93 (+/- 2.25 SE) pellet groups per 3-m radius subplot. Pellet group density declined over time, at approximately 8.8% per year (+/- 2.5% SE), but that slope was not statistically distinguishable from zero (2- tailed P=0.16). Following correction for detection biases, the proportion of surveyed points used by elk (i.e., PAO) ranged from 0.44 (+/- 0.07 SE) to 0.53 (+/- 0.07 SE) during the 4 winters. The estimated proportion of areas where elk pellets occurred (PAO) declined at a rate of 2.6% per year (+/- 1.2% per year SE), but that trend also was not statistically distinguishable from zero (2- tailed P=0.17). Statistical significance of a measure’s trend depends on both the magnitude (i.e., slope) of the observed trend and the number of years the trend continues in the same increasing or decreasing direction. Through simulation modeling we determined how many additional years of surveys would be required to reveal a statistically significant trend, based on the same trends in pellet group density and PAO, and associated variation, observed from 2009-2012. Assuming the same trends persist in the future, simulations indicated that there is a 70% probability that a statistically significant trend would be detected after two more years of conducting pellet group surveys. Relative use by elk during winter, as indexed by elk pellet group density, was generally greatest in the southeast region of the Fort Clatsop unit in or near the large freshwater marsh at the mouth of Colewort Creek and adjacent upland areas. Pellet group density was also higher than average in the north-central forested area, not far from a privately-owned pasture north of the park boundary. This spatial pattern in pellet group densities across the Fort Clatsop unit was consistent across all four years, although specific pellet group densities varied from year to year. Pellet group density declined significantly over time at two points in the southeast of the Fort Clatsop unit, even though pellet group density at those points remained higher than the unit average. Pellet group density increased significantly over time at one point in the north-central region, and at one point in the south-central region of the unit, indicating a slight shift in the distribution of elk use within the Fort Clatsop Unit over the four years. As an index of visitors’ opportunities to see elk in and around the Fort Clatsop Unit, we conducted replicated roadside elk surveys 3-5 times monthly during February, April, June, August, October and December 2008-2012. During each morning of survey, we searched for elk along four routes that totaled 32 km. We examined bimonthly trends in the numbers of elk groups seen, the total number of elk seen, and the observed composition ratios for those six months of the year. The average number of elk groups seen per survey ranged from 0.75 (+/- 0.32 SE) during February to a peak of 1.95 (+/- 0.36 SE) during June. Despite this seasonal variation in numbers of elk groups seen, the average total number of elk seen per morning was less variable. The average ratios of antlered elk to antlerless adult elk (i.e., bulls:cows) and calves to antlerless adult elk (i.e. calves:cows) varied seasonally, with the highest of both average ratios observed in August. We detected no significant trends in the average number of elk groups and total numbers of elk seen per survey from 2008-2012. Similarly, ratios of calves and antlered elk per antlerless elk did not differ over time. Elk groups were frequently seen from January to August in the southeast region of the Fort Clatsop unit, in the vicinity of Colewort Creek. Outside of NPS lands, we observed elk most frequently in open areas near the Astoria regional airport, in the pastures and forests immediately north of the Fort Clatsop unit and, prior to the construction of a residential development, in a pasture northwest of the Fort Clatsop unit. Elk monitoring at Lewis and Clark NHP is still in its initial years and additional monitoring will be required to verify trends that appear to be emerging. For example, the initial monitoring suggested incipient declining trends in both pellet group density and proportion of plots with pellets present, as well as, potentially, a small shift in elk distribution away from a new trail that was recently constructed in the southeast portion of the Fort Clatsop unit. Continued monitoring will aid in determining whether this local change in distribution persists (or, alternatively, resulted from short-term random variation), and whether there will be any positive or negative effect in the northern portion of the unit where a new trail has been constructed. High variability in road counts prevented our ability to find any clear trend in numbers or composition of elk observed in and near Fort Clatsop, but changes in the patterns of observations of elk from roadways suggest that residential development outside the park has reduced the available habitat for elk in some of the areas surveyed, and may have affected spatial use patterns of elk adjacent to some areas of the park. In addition to monitoring future effects of land use changes outside the park, continued monitoring may also prove useful for assessing elk responses to natural succession in forests disturbed by windthrow in December 2007 and to NPS vegetation management activities such as variable density thinning in the forest, trail development, and restoration at Otter Point tidal area and Colewort Creek Slough.
Oregon;Washington↗
Summary and evaluation of the quality of stormwater in Denver, Colorado, 2006-2010
Stormwater in the Denver area was sampled by the U.S. Geological Survey, in cooperation with the Urban Drainage and Flood Control District, in a network of 5 monitoring stations - 3 on the South Platte River and 2 on streams tributary to the South Platte River, Sand Creek, and Toll Gate Creek beginning in January 2006 and continuing through December 2010. Stormwater samples were analyzed at the U.S. Geological Survey National Water Quality Laboratory during 2006-2010 for water-quality properties such as pH, specific conductance, hardness, and residue on evaporation at 105 degrees Celsius; for constituents such as major ions (calcium, magnesium), organic carbon and nutrients, including ammonia plus organic nitrogen, ammonia, dissolved nitrite plus nitrate, total phosphorus, and orthophosphate; and for metals, including total recoverable and dissolved phases of copper, lead, manganese, and zinc. Samples collected during selected storms were also analyzed for bacteriological indicators such as Escherichia coli and fecal coliform at the Metro Wastewater Reclamation Laboratory. About 200 stormwater samples collected during storms characterize the quality of storm runoff during 2006-2010. In general, the quality of stormwater (2006-2010) has improved for many water-quality constituents, many of which had lower values and concentrations than those in stormwater collected in 2002-2005. However, the physical basis, processes, and the role of dilution that account for these changes are complex and beyond the scope of this report. The water-quality sampling results indicate few exceptions to standards except for dissolved manganese, dissolved zinc, and Escherichia coli . Stormwater collected at the South Platte River below Union Avenue station had about 10 percent acute or chronic dissolved manganese exceedances in samples; samples collected at the South Platte River at Denver station had less than 5 percent acute or chronic dissolved manganese exceedances. In contrast, samples collected at Toll Gate Creek above 6th Avenue at Aurora station, Sand Creek at mouth near Commerce City station, and the South Platte River at Henderson station, each had about 30 to 50 percent exceedances of both acute and chronic dissolved manganese standards. Of the samples collected at Sand Creek at mouth near Commerce City, 1 sample exceeded the acute standard and 4 samples exceeded the chronic standard for dissolved zinc, but no samples collected from the other sites exceeded either standard for zinc. Almost all samples of stormwater analyzed for Escherichia coli exceeded Colorado numeric standards. A numerical standard for fecal coliform is no longer applicable as of 2004. Results from the 2002-2005 study indicated that the general quality of stormwater had improved during 2002-2005 compared to 1998-2001, having fewer exceedances of Colorado standards, and showing downward trends for many water-quality values and concentrations. These trends coincided with general downward or relatively similar mean streamflows for the 2002-2005 compared to 1998-2001, which indicates that dilution may be a smaller influence on values and concentrations than other factors. For this report, downward trends were indicated for many constituents at each station during 2006-2010 compared to 2002-2005. The trends for mean streamflow for 2006-2010 compared to 2002-2005 are upward at all sites except for the South Platte River at Henderson, indicating that dilution by larger flows could be a factor in the downward concentration trends. At the South Platte River below Union Avenue station, downward trends were indicated for hardness, dissolved ammonia, dissolved orthophosphate, and dissolved copper. Upward trends at South Platte River below Union Avenue were indicated for pH. At the South Platte River at Denver station, downward trends were indicated for total ammonia plus organic nitrogen, dissolved ammonia, dissolved nitrite plus nitrate, dissolved orthophosphate, total phosphorus, dissolved organic carbon, and dissolved lead, manganese, and zinc, and total recoverable zinc. An upward trend in properties and constituents at South Platte River at Denver was indicated for pH. At Toll Gate Creek above 6th Avenue at Aurora, downward trends were indicated for residue on evaporation, total ammonia plus organic nitrogen, dissolved ammonia, dissolved orthophosphate, total phosphorus, and total recoverable copper, lead, manganese, and zinc. Upward trends in properties and constituents at Toll Gate Creek above 6th Avenue at Aurora were indicated for pH, specific conductance, and dissolved nitrite plus nitrate. At Sand Creek at mouth near Commerce City, downward trends were indicated for hardness, dissolved calcium, total ammonia plus organic nitrogen, and dissolved ammonia, orthophosphate, manganese, and zinc. An upward trend in properties and constituents at Sand Creek at mouth near Commerce City was indicated for pH. Downward trends at South Platte River at Henderson were indicated for specific conductance, hardness, dissolved magnesium, residue on evaporation, total ammonia plus organic nitrogen, dissolved ammonia, dissolved nitrite plus nitrate, dissolved orthophosphate, total phosphorus, dissolved lead and manganese, and total recoverable copper, lead, manganese, and zinc.
Colorado↗