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At least 685 records · Page 38Linked to original sources

USGS2000

Occurrence of pesticides in five rivers of the Mississippi Embayment Study Unit, 1996-98

The occurrence and temporal distribution of more than 80 pesticides and pesticide metabolites were determined in five rivers of the Mississippi Embayment National Water-Quality Assessment study unit from February 1996 through January 1998. More than 230 samples were collected and analyzed during the 2-year study. The five rivers sampled included three rivers with small, primarily agricultural watersheds; one river with a small urban watershed in Memphis, Tennessee; and one large river with mixed land use (row-crop agriculture, pasture, forest, and urban). Pesticides, usually herbicides, were frequently detected in water samples from every river. Insecticides were frequently detected (chlorpyrifos and diazinon in all samples) only in the river that drains the urban watershed. The occurrence of pesticides in surface water varied among the agricultural watersheds as well as between the agricultural and urban watersheds. The pesticides detected in the rivers that drain the agricultural watersheds were related to the major crop types cultivated in the watershed?corn is mostly grown in the northern part of the study unit, whereas cotton and rice are mostly grown in the southern part. The occurrence of pesticides in the Yazoo River, which drains the mixed land-use watershed, was similar to pesticide occurrence in the rivers that drain smaller agricultural watersheds, although concentrations were lower in the Yazoo River. Likewise, simazine, which was detected in all urban stream samples, was also detected in all Yazoo River samples, but in lower concentrations. The aquatic-life criteria for diazinon and chlorpyrifos was exceeded in 24 of 25 and 12 of 25 urban river samples, respectively, but only once or twice in agricultural and mixed-use watershed samples. Atrazine exceeded the aquatic-life criterion in about 20 percent of the samples from each river, particularly in the spring following pesticide application.

Water-Resources Investigations Report↗

USGS2018

Characteristics of successful volunteer-led urban forest tree committees in Massachusetts

Citizen engagement through urban forest tree committee volunteer service may aid in providing essential experience, ideas, and skills that support municipal tree management. Using semi-structured, research interviews with tree committee (TC) representatives from across the Commonwealth of Massachusetts, this study addresses current knowledge gaps concerning the general composition, processes, and relationships of volunteer-led urban forest tree committees. Our findings indicate that TC representatives are typically motivated, passionate volunteers who generally desire to work cooperatively with the many associations, organizations, and agencies that comprise the local socio-political landscape. Our findings also indicate it is important that TC representatives make a sustained, concerted effort to work collaboratively with their local tree warden to advance the care of their community’s urban trees. Furthermore, it is also essential that municipal managers and decision-makers attempt to provide TC volunteers with appropriate training opportunities, resources, as well as demonstrate appreciation, to further encourage and solidify volunteer-engagement in urban forestry at the local level.

Massachusetts↗

USGS1997

Distribution of dissolved pesticides and other water quality constituents in small streams, and their relation to land use, in the Willamette River Basin, Oregon, 1996

Water quality samples were collected at sites in 16 randomly selected agricultural and 4 urban subbasins as part of Phase III of the Willamette River Basin Water Quality Study in Oregon during 1996. Ninety-five samples were collected and analyzed for suspended sediment, conventional constituents (temperature, dissolved oxygen, pH, specific conductance, nutrients, biochemical oxygen demand, and bacteria) and a suite of 86 dissolved pesticides. The data were collected to characterize the distribution of dissolved pesticide concentrations in small streams (drainage areas 2.6? 13 square miles) throughout the basin, to document exceedances of water quality standards and guidelines, and to identify the relative importance of several upstream land use categories (urban, agricultural, percent agricultural land, percent of land in grass seed crops, crop diversity) and seasonality in affecting these distributions. A total of 36 pesticides (29 herbicides and 7 insecticides) were detected basinwide. The five most frequently detected compounds were the herbicides atrazine (99% of samples), desethylatrazine (93%), simazine (85%), metolachlor (85%), and diuron (73%). Fifteen compounds were detected in 12?35% of samples, and 16 compounds were detected in 1?9% of samples. Water quality standards or criteria were exceeded more frequently for conventional constituents than for pesticides. State of Oregon water quality standards were exceeded at all but one site for the indicator bacteria E. coli, 3 sites for nitrate, 10 sites for water temperature, 4 sites for dissolved oxygen, and 1 site for pH. Pesticide concentrations, which were usually less than 1 part per billion, exceeded State of Oregon or U.S. Environmental Protection Agency aquatic life toxicity criteria only for chlorpyrifos, in three samples from one site; such criteria have been established for only two other detected pesticides. However, a large number of unusually high concentrations (1?90 parts per billion) were detected, indicating that pesticides in the runoff sampled in these small streams were more highly concentrated than in the larger streams sampled in previous studies. These pulses could have had short term toxicological implications for the affected streams; however, additional toxicological assessment of the detected pesticides was limited because of a lack of available information on the response of aquatic life to the observed pesticide concentrations. Six pesticides, including atrazine, diuron, and metolachlor, had significantly higher (p<0.08 for metolachlor, p<0.05 for the other five) median concentrations at agricultural sites than at urban sites. Five other compounds ?carbaryl, diazinon, dichlobenil, prometon, and tebuthiuron?had significantly higher (p<0.05) concentrations at the urban sites than at the agricultural sites. Atrazine, metolachlor, and diuron also had significantly higher median concentrations at southern agricultural sites (dominated by grass seed crops) than northern agricultural sites. Other compounds that had higher median concentrations in the south included 2,4-D and metribuzin, which are both used on grass seed crops, and triclopyr, bromacil, and pronamide. A cluster analysis of the data grouped sites according to their pesticide detections in a manner that was almost identical to a grouping made solely on the basis of their upstream land use patterns (urban, agricultural, crop diversity, percentage of basin in agricultural production). In this way inferences about pesticide associations with different land uses could be drawn, illustrating the strength of these broad land use categories in determining the types of pesticides that can be expected to occur. Among the associations observed were pesticides that occurred at a group of agricultural sites, but which have primarily noncropland uses such as vegetation control along rights-of-way. Also, the amount of forested land in a basin was negatively associated with pesticide occurrence, sugges

Water-Resources Investigations Report↗

USGS2005

Trace elements in streambed sediments of small subtropical streams on O'ahu, Hawai'i: Results from the USGS NAWQA program

Data are presented for trace element concentrations determined in the <63 ??m fraction of streambed sediment samples collected at 24 sites on the island of O'ahu, Hawai'i. Sampling sites were classified as urban, agricultural, mixed (urban/agricultural), or forested based on their dominant land use, although the mixed land use at selected sampling sites consisted of either urban and agricultural or forested and agricultural land uses. Forest dominated sites were used as reference sites for calculating enrichment factors. Trace element concentrations were compared to concentrations from studies conducted in the conterminous United States using identical methods and to aquatic-life guidelines provided by the Canadian Council of Ministers of the Environment. A variety of elements including Pb, Cr, Cu and Zn exceeded the aquatic-life guidelines in selected samples. All of the Cr and Zn values and 16 of 24 Cu values exceeded their respective guidelines. The potential toxicity of elements exceeding guidelines, however, should be considered in the context of strong enrichments of selected trace elements attributable to source rocks in Hawai'i, as well as in the context of the abundance of fine-grained sediment in the streambed of O'ahu streams. Statistical methods including cluster analysis, Kruskal-Wallis non-parametric test, correlation analysis, and principal component analysis (PCA) were used to evaluate differences and elucidate relationships between trace elements and sites. Overall, trace element distributions and abundances can be correlated to three principal sources of elements. These include basaltic rocks of the volcanic edifice (Fe, Al, Ni, Co, Cr, V and Cu), carbonate/seawater derived elements (Mg, Ca, Na and Sr), and elements enriched owing to anthropogenic activity (P, Sn, Cd, Sn, Ba and Pb). Anthropogenic enrichment gradients were observed for Ba, Cd, Pb, Sn and Zn in the four streams in which sediments were collected upstream and downstream. The findings of this study are generally similar to but differ slightly from previous work on sediments and suspended particulate matter in streams, from two urban watersheds of O'ahu, Hawai'i. Inter-element associations in the latter were often stronger and indicated a mixture of anthropogenic, agricultural and basaltic sources of trace elements. Some elements fell into different statistical categories in the two studies, owing in part to differences in study design and the hydrogeological constraints on the respective study areas.

Applied Geochemistry↗

USGS2001

Effect of land cover, habitat fragmentation and ant colonies on the distribution and abundance of shrews in southern California

Because effects of habitat fragmentation and anthropogenic disturbance on native animals have been relatively little studied in arid areas and in insectivores, we investigated the roles of different land covers, habitat fragmentation and ant colonies on the distribution and abundance of shrews, Notiosorex crawfordi and Sorex ornatus , in southern California. Notiosorex crawfordi was the numerically dominant species (trap-success rate 0·52) occurring in 21 of the 22 study sites in 85% of the 286 pitfall arrays used in this study. Sorex ornatus was captured in 14 of the sites, in 52% of the arrays with a total trap-success rate of 0·2. Neither of the species was found in one of the sites. The population dynamics of the two shrew species were relatively synchronous during the 4–5-year study; the peak densities usually occurred during the spring. Precipitation had a significant positive effect, and maximum temperature a significant negative effect on the trap-success rate of S. ornatus . Occurrence and abundance of shrews varied significantly between sites and years but the size of the landscape or the study site had no effect on the abundance of shrews. The amount of urban edge had no significant effect on the captures of shrews but increased edge allows invasion of the Argentine ants, which had a highly significant negative impact on the abundance of N. crawfordi . At the trap array level, the percentage of coastal sage scrub flora had a significant positive, and the percentage of other flora had a significant negative effect on the abundance of N. crawfordi . The mean canopy height and the abundance of N. crawfordi had a significant positive effect on the occurrence of S. ornatus . Our study suggests that the loss of native coastal sage scrub flora and increasing presence of Argentine ant colonies may significantly effect the distribution and abundance of N. crawfordi . The very low overall population densities of both shrew species in most study sites make both species susceptible to extinction in isolated habitat fragments due to environmental stochasticity, and anthropogenic disturbance.

Journal of Animal Ecology↗

USGS2010

Interpolating a consumption variable for scaling and generalizing potential population pressure on urbanizing natural areas

Measures of population pressure, referring in general to the stress upon the environment by human consumption of resources, are imperative for environmental sustainability studies and management. Development based on resource consumption is the predominant factor of population pressure. This paper presents a spatial model of population pressure by linking consumption associated with regional urbanism and ecosystem services. Maps representing relative geographic degree and extent of natural resource consumption and degree and extent of impacts on surrounding areas are new, and this research represents the theoretical research toward this goal. With development, such maps offer a visualization tool for planners of various services, amenities for people, and conservation planning for ecologist. Urbanization is commonly generalized by census numbers or impervious surface area. The potential geographical extent of urbanism encompasses the environmental resources of the surrounding region that sustain cities. This extent is interpolated using kriging of a variable based on population wealth data from the U.S. Census Bureau. When overlayed with land-use/land-cover data, the results indicate that the greatest estimates of population pressure fall within mixed forest areas. Mixed forest areas result from the spread of cedar woods in previously disturbed areas where further disturbance is then suppressed. Low density areas, such as suburbanization and abandoned farmland are characteristic of mixed forest areas.

Missouri↗

USGS2022

Refining sources of polychlorinated biphenyls in the Back River watershed, Baltimore, Maryland, 2018–2020

Older urban landscapes present unique and complex stressors to urban streams and their habitats through the introduction of legacy and emerging toxic contaminants. Contaminant sources are often associated with various developed land uses such as older residential areas, active and former industrial sites, contaminated sites, and effluents from municipal wastewater treatment plant discharges. These landscapes have a history of legacy contaminant use such as polychlorinated biphenyls (PCBs) resulting in impacts to sediment and water in these complex environments. Despite the ban of PCBs in new commercial use in 1979, PCB contamination is still widespread in the environment, with many fish consumption advisories throughout the Chesapeake Bay region based on elevated PCBs. Several watersheds in the Baltimore region have mandated reductions in PCBs per total maximum daily loads in tidal waters of the watersheds in order to promote compliance with water quality standards. Some of these mandated reductions (for example, regulated watershed runoff) specified in the total maximum daily loads are the responsibility of the local jurisdictions as part of their phase 1 National Pollutant Discharge Elimination System municipal separate storm sewer system permit. In cooperation with the Baltimore City Department of Public Works and Maryland Department of the Environment, the U.S. Geological Survey and University of Maryland, Baltimore County conducted a study from 2018 to 2020 to refine the sources of PCBs from the City of Baltimore into Back River and to use the results to improve the conceptual site model of PCBs in the Back River watershed. PCB concentrations in the water column of the nontidal streams in Back River watershed are relatively consistent throughout both tributaries, with greater concentrations detected in samples collected from Moores Run but greater loads estimated in samples collected from Herring Run. PCB concentrations measured in the bed sediments and analysis of the flux between sediment porewater (hereafter porewater) and surface water within the tributaries suggest that there are no stationary legacy sources within the stream channels. The bulk of PCB mass entering the system from these nontidal tributaries appears to be introduced primarily during storm events. While only one storm event was sampled and concentrations were quantified only in Herring Run, solids captured during the storm were characterized by increases in PCB mass and overall suspended solids concentrations. Although the bioavailability of the PCB-associated sediment is unknown, this mechanism appears to warrant additional attention to better understand how concentrations vary under different storm conditions and temporally. The importance of contaminated stormwater in loading to Herring Run is further supported by the PCB concentrations in storm drain sediments collected near the tributary, which were present in higher concentrations and were characterized by different homolog signatures compared to that in bed sediments. The observations in the tributaries differed from PCB concentrations and sediment characteristics downstream from the City of Baltimore boundary, in the upper tidal area of the main stem of Back River, particularly at the passive sampler locations BRT–1 and BRT–3. This depositional environment is characterized by higher organic content in sediments and higher concentrations of PCBs in porewater, which result in the possible flux of contaminants from sediment to the water column. This flux is generally opposite of that observed in the nontidal tributaries and the farthest upstream tidal site (BRT–2) and may be a result of the possible settling of sediment particles introduced via suspended solids in stormwater. Despite an observed considerable reduction in overall PCB mass loading to and from the Back River Wastewater Treatment Plant (BRWWTP) (and similar reductions observed in biosolids) compared to the estimates previously reported from 2015, effluent from the BRWWTP continues to be a primary source of PCBs to Back River. The current study confirmed the likeliness of fat, oil, and grease deposits within the miles of sewer pipe as a source of PCBs to the BRWWTP influent. The differences between PCB concentrations in fat, oil, and grease deposits found in pipes (during replacement) compared to that of the BRWWTP suggest that legacy deposits may contain higher PCB concentrations and may act as a source of PCBs to passing sewage, eventually entering the BRWWTP. Variation in freely dissolved concentrations in the sewer system was apparent through the analysis of PCBs in the primary pump stations using passive sampling, with the largest contribution to the influent attributed to a single pump station and associated piping. The contribution of PCBs to Herring Run and Moores Run via sanitary sewer overflows compared to the BRWWTP effluent is negligible, similar to reports from another large urban wastewater treatment plant. Therefore, decreased occurrence of sanitary sewer overflows is not expected to largely decrease PCB loads. Results of this study suggest that targeted, sediment-capture best management practices in Back River watershed could be an effective way to reduce PCB mass loading assuming that deposited contaminated sediments are effectively isolated. Recent studies of some common urban best management practices such as bioretention have shown removal of PCBs within the stormwater control structures. In addition, appropriately timed street sweeping practices with appropriate collection equipment may be an effective way to reduce contaminants such as PCBs from road runoff sources. Reductions in concentrations and mass loading within the sewer system measured in this study compared to that estimated 5 years prior reflect the possible success of ongoing gray infrastructure management actions. Reductions may be attributable to enhanced nutrient reduction upgrades to the BRWWTP and extensive capital improvements and maintenance to the sewer system. This study employed a combined sampling approach and a variety of sampling methods to include low-density polyethylene passive samplers, high-volume water samples, and grab samples of both water and sediment to characterize the PCB inputs to Herring Run, Moores Run, and Back River. Incorporating the passive samplers provided a time-weighted average of the freely dissolved concentration in the surface water, porewater, WWTP influent and effluent, and pump station influent over the deployment period with picogram per liter detection limits. A similar monitoring approach from this study could be implemented within other subwatersheds or municipal separate storm sewer system jurisdictions to assist in refining primary sources of PCBs in order to inform appropriate mitigation approaches.

Maryland↗

USGS2002

Concentrations of pesticides and pesticide degradates in the Croton River Watershed in southeastern New York, July-September 2000

Thirty-seven pesticides and (or) pesticide degradates were detected in baseflow samples collected from 47 stream sites in the Croton River Watershed (374 square miles) in southeastern New York in the summer of 2000. The Croton Reservoir provides about 10 percent of New York City's water supply. Maximum concentrations of most pesticides detected did not exceed 0.1 μg/L (micrograms per liter). This study, by the U.S. Geological Survey in cooperation with the New York State Department of Environmental Conservation, was conducted from July through September 2000 and entailed analysis of the samples for more than 150 pesticides and their degradates. Nine compounds were detected at a concentration greater than 0.10 μg/L; three of these were insecticides (diazinon, carbaryl, and imidacloprid), one was a fungicide (mycobutanil), and five were herbicides (simazine, 2,4-D, diuron, hexazinone, and 2,4-D methyl esther). Only two of these compounds (simazine and 2,4-D) were detected at a concentration exceeding 1 μg/L; the simazine concentration exceeded the New York State surface-water standard of 0.5 μg/L. Two insecticides (diazinon and azinphos-methyl) exceeded aquatic-life-protection standard in one sample each. Concentrations of three insecticides (chlorpyrifos, carbaryl, and malathion) were more than 50 percent of the aquatic-life-protection standards in one sample each. Total concentrations of insecticides and herbicides (the sum of the concentrations, whereby all concentrations below the detection limit were set to zero), and the concentrations of the herbicide prometon and the insecticide diazinon, were highest in samples from watersheds with population densities greater than 510 per square mile (21 sites); therefore, the presence of these compounds is attributable to urban, residential, and other developed land uses. The data obtained in this study are useful for making general comparisons among watersheds with differing land uses, but the concentrations represent baseflow conditions and, thus, are probably lower than the annual maximum concentrations in these streams. A July baseflow sample had total insecticide and fungicide concentrations of less than 0.03 μg/L, whereas a stormflow sample collected at the same site 2 weeks later had a corresponding concentration greater than 0.10 μg/L. Total herbicide concentrations for the July baseflow and stormflow samples were around 0.03 μg/L, but that for a stormflow sample collected at the same site 2 months later was greater than 20 μg/L.

Connecticut, New York↗

USGS2014

Status and understanding of groundwater quality in the South Coast Interior groundwater basins, 2008: California GAMA Priority Basin Project

Groundwater quality in the approximately 653-square-mile (1,691-square-kilometer) South Coast Interior Basins (SCI) study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The South Coast Interior Basins study unit contains eight priority groundwater basins grouped into three study areas, Livermore, Gilroy, and Cuyama, in the Southern Coast Ranges hydrogeologic province. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA South Coast Interior Basins study was designed to provide a spatially unbiased assessment of untreated (raw) groundwater quality within the primary aquifer system, as well as a statistically consistent basis for comparing water quality between basins. The assessment was based on water-quality and ancillary data collected by the USGS from 50 wells in 2008 and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system was defined by the depth intervals of the wells listed in the CDPH database for the SCI study unit. The quality of groundwater in the primary aquifer system may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. The first component of this study, the status of the current quality of the groundwater resource, was assessed by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as trace elements and minor ions. This status assessment is intended to characterize the quality of groundwater resources within the primary aquifer system of the SCI study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration divided by the health- or aesthetic-based benchmark concentration) were used for evaluating groundwater quality for those constituents that have Federal or California regulatory or non-regulatory benchmarks for drinking-water quality. A relative-concentration greater than 1.0 indicates a concentration greater than a benchmark, and a relative-concentration less than or equal to 1.0 indicates a concentration equal to or less than a benchmark. Relative-concentrations of organic constituents and special-interest constituents were classified as “high” (relative-concentration greater than 1.0), “moderate” (relative-concentration greater than 0.1 and less than or equal to 1.0), or “low” (relative-concentration less than or equal to 0.1). Relative-concentrations of inorganic constituents were classified as “high” (relative-concentration greater than 1.0), “moderate” (relative-concentration greater than 0.5 and less than or equal to 1.0), or “low” (relative-concentration less than or equal to 0.5). Aquifer-scale proportion was used as the primary metric in the status assessment for evaluating regional-scale groundwater quality. High aquifer-scale proportion is defined as the percentage of the area of the primary aquifer system with a relative-concentration greater than 1.0 for a particular constituent or class of constituents; percentage is based on an areal rather than a volumetric basis. Moderate and low aquifer-scale proportions were defined as the areal percentage of the primary aquifer system with moderate and low relative-concentrations, respectively. Two statistical approaches—grid-based and spatially weighted—were used to evaluate aquifer-scale proportions for individual constituents and classes of constituents. Grid-based and spatially weighted estimates were comparable in the SCI study unit (within 90-percent confidence intervals). Inorganic constituents (one or more) with health-based benchmarks were detected at high relative-concentrations in 29 percent of the primary aquifer system, at moderate relative-concentrations in 37 percent, and at low relative-concentrations in 34 percent. High aquifer-scale proportions of inorganic constituents primarily reflected high aquifer-scale proportions of nitrate (14 percent), boron (8.6 percent), molybdenum (8.6 percent), and arsenic (5.7 percent). In contrast, the relative-concentrations of organic constituents (one or more) were high in 1.6 percent, moderate in 2.0 percent, and low or not detected in 96 percent of the primary aquifer system. Of the 207 organic and special-interest constituents analyzed for, 15 constituents were detected. Perchlorate was found at moderate relative-concentrations in 34 percent of the aquifer. Two organic constituents were frequently detected (in greater than 10 percent of samples): the trihalomethane chloroform and the herbicide simazine. The second component of this study, the understanding assessment, identified natural and human factors that may have affected groundwater quality by evaluating land use, physical characteristics of the wells, and geochemical conditions of the aquifer. This evaluation was done by using statistical tests of correlations between these potential explanatory factors and water-quality data. Concentrations of arsenic, molybdenum, and manganese were generally greater in anoxic and pre-modern groundwater than other groundwater. In contrast, concentrations of nitrate and perchlorate were significantly higher in oxic and modern groundwater. Concentrations of simazine were greater in modern than pre-modern groundwater. Chloroform detections were positively correlated with greater urban land use. Boron concentrations and chloroform detections were higher in the Livermore study area than in the other study areas of the SCI; total dissolved solids and sulfate concentrations were greater in the Cuyama study area.

California↗

USGS1975

An introduction to the processes, problems, and management of urban lakes

Lakes are bodies of water formed in depressions on the earth's surface, and as such, act as depositories for a variety of chemical and biological materials. The study of lakes has become increasingly prevalent in recent years. Lakes are a valuable resource, and their multiple uses have made them susceptible to water-quality problems such as algal blooms, sediment deposition and fish kills. These problems are products of the eutrophication process (enrichment, aging and extinction of lakes), which is often accelerated by man. Therefore, it becomes important to understand the properties and processes of lakes which govern lake enrichment, and the measures available to control enrichment. Lakes are described in terms of their physical (light penetration, temperature, sediment, and morphology), chemical (chemical constituents, plant nutrients:, and dissolved gases) and biological (plankton, benthos, and nekton) properties. These properties are all interre]ated, and are important variables to measure to evaluate water quality. In addition, lake processes, such as photosynthesis, respiration, eutrophication, and biogeochemical cycling, are important factors in determining the sources and extent of enrichment, and managing a lake for maximum benefit. Meeting demands for water of high quality requires a general knowledge of lake properties and processes, coupled with lake-basin planning, watershed and lake management, and water-quality control. There are many lake-management and control practices, but the best tools for quality control are preventive measures. Once extensive enrichment has occurred, there are few management or control options available. As lake studies become more common, sampling techniques for data collection need increased accuracy and consistency, in order to make meaningful comparisons between different lakes. Therefore, the report discusses the main factors involved in conducting lake studies. These factors include the types and frequency of measurements useful in lake reconnaissance studies and a review of literature on sampling equipment and techniques. A glossary of selected terms begins the report, which is intended for guideline use by urban planners and managers.

Circular↗

USGS2012

Evaluation of the effects of Middleton's stormwater-management activities on streamflow and water-quality characteristics of Pheasant Branch, Dane County, Wisconsin 1975-2008

Few long-term data sets are available for evaluating the effects of urban stormwater-management practices. Over 30 years of data are available for evaluating the effectiveness of such practices by the city of Middleton, Wis. Analysis of streamflow and water-quality data collected on Pheasant Branch, demonstrates the relation between the changes in the watershed to the structural and nonstructural best management practices put in place during 1975-2008. A comparison of the data from Pheasant Branch with streamflow and water-quality data (suspended sediment and total phosphorus) collected at other nearby streams was made to assist in the determination of the possible causes of the changes in Pheasant Branch. Based on 34 years of streamflow data collected at the Pheasant Branch at Middleton streamflow-gaging station, flood peak discharges increased 37 percent for the 2-year flood and 83 percent for the 100-year flood. A comparison of data for the same period from an adjacent rural stream, Black Earth at Black Earth had a 43 percent increase in the 2-year flood peak discharge and a 140-percent increase in the 100-year flood peak discharge. Because the flood peak discharges on Pheasant Branch have not increased as much as Black Earth Creek it appears that the stormwater management practices have been successful in mitigating the effects of urbanization. Generally urbanization results in increased flood peak discharges. The overall increase in flood peak discharges seen in both streams probably is the result of the substantial increase in precipitation during the study period. Average annual runoff in Pheasant Branch has also been increasing due to increasing average annual precipitation and urbanization. The stormwater-management practices in Middleton have been successful in decreasing the suspended-sediment and total phosphorus loads to Lake Mendota from the Pheasant Branch watershed. These loads decreased in spite of increased annual runoff and flood peaks, which are often expected to produce higher sediment and phosphorus loads. The biggest decreases in sediment and phosphorus loads occurred after 2001 when a large detention pond, the Confluence Pond, began operation. Since 2001, the annual suspended-sediment load has decreased from 2,650 tons per year to 1,450 tons per year for a 45-percent decrease. The annual total phosphorus load has decreased from 12,200 pounds per year to 6,300 pounds per year for a 48-percent decrease. A comparison of Pheasant Branch at Middleton with two other streams, Spring Harbor Storm Sewer and Yahara River at Windsor, that drain into Lake Mendota shows that suspended-sediment and total phosphorus load decreases were greatest at Pheasant Branch at Middleton. Prior to the construction of the Confluence Pond, annual suspended-sediment yield and total phosphorus yield from Pheasant Branch watershed was the largest of the three watersheds. After 2001, suspended-sediment yield was greatest at Spring Harbor Storm Sewer, and lowest at Yahara at Windsor; annual total phosphorus yield was greater at Yahara River at Windsor than that of Pheasant Branch. The stormwater-quality plan for Middleton shows that the city has met the present State of Wisconsin Administrative Code chap. NR216/NR151 requirements of reducing total suspended solids by 20 percent for the developed area in Middleton. In addition, the city already has met the 40-percent reduction in total suspended solids required by 2013. Snow and ice melt runoff from road surfaces and parking lots following winter storms can effect water quality because the runoff contains varying amounts of road salt. To evaluate the effect of road deicing on stream water quality in Pheasant Branch, specific conductance and chloride were monitored during two winter seasons. The maximum estimated concentration of chloride during the monitoring period was 931 milligrams per liter, which exceeded the U.S. Environmental Protection Agency acute criterion of 860 milligrams per liter. Chloride concentrations exceeded the U.S. Environmental Protection Agency chronic criterion of 230 milligrams per liter for at least 10 days during February and March 2007 and for 45 days during the 2007-8 winter seasons. The total sodium chloride load for the monitoring period was 1,720 tons and the largest sodium chloride load occurred in March and April of each year.

Wisconsin↗

USGS2013

Effects of climate change and urban development on the distribution and conservation of vegetation in a Mediterranean type ecosystem

Climate and land-use changes are projected to threaten biodiversity over this century. However, few studies have considered the spatial and temporal overlap of these threats to evaluate how ongoing land-use change could affect species ranges projected to shift outside conservation areas. We evaluated climate change and urban development effects on vegetation distribution in the Southwest ecoregion, California Floristic Province, USA. We also evaluated how well a conservation network protects suitable habitat for rare plant species under these change projections and identified primary sources of uncertainty. We used consensus-based maps from three species distribution models (SDMs) to project current and future suitable habitat for 19 species representing different functional types (defined by fire-response – obligate seeders, resprouting shrubs – and life forms – herbs, subshrubs), and range sizes (large/common, small/rare). We used one spatially explicit urban growth projection; two climate models, emission scenarios, and probability thresholds applied to SDMs; and high-resolution (90 m) environmental data. We projected that suitable habitat could disappear for 4 species and decrease for 15 by 2080. Averaged centroids of suitable habitat (all species) were projected to shift tens (up to hundreds) of kilometers. Herbs showed a small-projected response to climate change, while obligate seeders could suffer the greatest losses. Several rare species could lose suitable habitat inside conservation areas while increasing area outside. We concluded that (i) climate change is more important than urban development for vegetation habitat loss in this ecoregion through 2080 due to diminishing amounts of undeveloped private land in this region; (ii) the existing conservation plan, while extensive, may be inadequate to protect plant diversity under projected patterns of climate change and urban development, (iii) regional assessments of the dynamics of the drivers of biodiversity change based on high-resolution environmental data and consensus predictive mapping, such as this study, are necessary to identify the species expected to be the most vulnerable and to meaningfully inform regional-scale conservation.

California↗

USGS2016

Plastic debris in 29 Great Lakes tributaries: Relations to watershed attributes and hydrology

Plastic debris is a growing contaminant of concern in freshwater environments, yet sources, transport, and fate remain unclear. This study characterized the quantity and morphology of floating micro- and macroplastics in 29 Great Lakes tributaries in six states under different land covers, wastewater effluent contributions, population densities, and hydrologic conditions. Tributaries were sampled three or four times each using a 333 μm mesh neuston net. Plastic particles were sorted by size, counted, and categorized as fibers/lines, pellets/beads, foams, films, and fragments. Plastics were found in all 107 samples, with a maximum concentration of 32 particles/m 3 and a median of 1.9 particles/m 3 . Ninety-eight percent of sampled plastic particles were less than 4.75 mm in diameter and therefore considered microplastics. Fragments, films, foams, and pellets/beads were positively correlated with urban-related watershed attributes and were found at greater concentrations during runoff-event conditions. Fibers, the most frequently detected particle type, were not associated with urban-related watershed attributes, wastewater effluent contribution, or hydrologic condition. Results from this study add to the body of information currently available on microplastics in different environmental compartments, including unique contributions to quantify their occurrence and variability in rivers with a wide variety of different land-use characteristics while highlighting differences between surface samples from rivers compared with lakes.

Environmental Science & Technology↗

USGS2003

Associations among land-use, habitat characteristics, and invertebrate community structure in nine streams on the island of Oahu, Hawaii

The island of Oahu is one of 51 study units established as part of the U.S. Geological Surveys National Water-Quality Assessment (NAWQA) program to assess the status and trends of the Nations surface and ground-water resources, and to link status and trends with an understanding of the natural and human factors that affect water quality. As part of the NAWQA program, benthic invertebrate communities were surveyed at ten sites in nine streams representing the three main types of land use on Oahu: urban, agriculture, and forested. At each sampling site, habitat characteristics were determined at a range of spatial scales including drainage basin, segment, reach, transect, and point. Associations among land use, habitat characteristics, and benthic invertebrate community structure were examined. The rapid population growth and increasing urbanization on Oahu has resulted in substantial stream habitat alteration. Instream habitat characteristics at the urban and mixed (urban and agriculture) land-use sites were markedly different from those at the forested sites. Urban and mixed land-use sites, most of which were channelized, tended to have less riparian vegetation, higher water temperatures, smaller substrate, and higher levels of embeddedness and siltation than sites in forested watersheds. The majority of invertebrate taxa identified during this study were non-native. Invertebrate abundance was lower at urban and mixed land-use sites than at forested sites, while species richness (the number of different species) showed the opposite pattern. Multivariate analyses indicated that invertebrate species composition was similar at sites with similar land use. Aquatic insects of the orders Diptera and Trichoptera were the most common insects in all samples. The ratio of Diptera to Trichoptera abundance varied with urbanization. Forested sites were dominated by Trichoptera, and urban and mixed land-use sites were dominated by Diptera. Molluscs typically occurred in channelized urban streams although no native molluscs were collected during this study. The most abundant molluscs were pan-tropical thiarid snails, the introduced clam Corbicula fluminea, and the limpet Ferrissia sharpi. Two native and four introduced species of Crustacea were collected at the sampling sites. To effectively manage Hawaiian watersheds for native species and the communities they form, the ways in which these species respond to human-induced changes needs to be understood. This report provides important information describing the usefulness of invertebrates as indicators of stream quality conditions and how an integrated assessment of stream quality will allow for the development of appropriate monitoring and management strategies.

Water-Resources Investigations Report↗

USGS1964

Effect of urban growth on streamflow regimen of Permanente Creek, Santa Clara County, California

This report presents the results of an investigation of the effect of urban growth on the streamflow regimen of Permanente Creek in Mountain View, Santa Clara County, Calif. The data available did not permit a complete study of all hydrologic aspects, but there is conclusive evidence that the volume of storm runoff produced by rainfall on the valley floor has increased substantially as a result of urbanization. In 1945, storm runoff from the 5.12-square mile project area was insufficient to balance channel losses, and the streamflow entering the project area in the Permanente Creek channel was greater than that leaving the area. If, however, total outflow from the project area is considered to be the sum of the streamflow leaving the area plus channel seepage in the area, the ratio of total outflow to inflow was 1:18. By 1958, storm runoff from the project area was far in excess of channel losses and the ratio of total outflow to inflow was 1:70. This increase in outflow is attributed to the fact that urban development during the period 1945 to 1958 increased the extent of impervious surface in the project area from about 4 percent to 19 percent. The effect of urban growth in other basins in Santa Clara County should be investigated before any attempt is made to project the quantitative results of this study to other areas in the county.

Water Supply Paper↗

USGS2018

Increasing soil organic carbon to mitigate greenhouse gases and increase climate resiliency for California

Rising air temperatures are projected to continue to drive up urban, agricultural, and rangeland water use, straining both surface and groundwater resources. Scientific studies have shown that managing farms, ranches, and public lands to increase soil carbon can increase soil waterholding capacity and increase hydrologic benefits such as increased baseflows and aquifer recharge, reduced flooding and erosion, and reduced climate-related water deficits. Coincident improvements in forage and crop yields are also indicated, while simultaneously sequestering carbon, reducing atmospheric greenhouse gases and mitigating climate change. This study was developed to consider the multiple benefits of increasing the organic matter content of soils across California’s working lands. Study results indicate that a one-time ¼” application of compost to rangelands can lead to carbon sequestration rates in soils that are maximized after approximately 15 years, and more than offset greenhouse gas emissions stimulated by the compost addition for at least five decades longer. Modeled increases in total soil organic matter of 3% enhanced hydrologic benefits across 97% of working lands, and reduced climate change impacts. Economic valuation indicated all benefits increasing over time, demonstrating a large potential for the California carbon market to support incentives in regionalizing the impacts in the coming decades. Socioeconomic and related land use pressures pose barriers to implementing management practices to increase soil organic matter by driving conversion of rangeland to urban or to more greenhouse-gas emission intensive agriculture. Results can be effectively used with land use change scenarios to identify where on California’s working lands hydrologic benefits of soil organic matter enhancement coincide with development risk, highlighting counties in California in which there may be resilience to climate change when strategic soil management and land conservation are combined.

California↗

USGS2007

Effects of agriculture and urbanization on quality of shallow ground water in the arid to semiarid western United States, 1993-2004

Within the Western United States, agricultural and rural lands are being developed into commercial and residential areas. With changes in land use and increasing population, greater demands are placed on water resources for agricultural, industrial, and domestic supplies. Many areas in the Western United States rely exclusively on ground water as their source of drinking water. Areas that use surface-water resources often need to supplement this supply with ground water. Generally, shallow ground water is susceptible to fluctuating water quality within relatively short time scales and therefore can be used as an indicator of land-use stresses that may, in time, affect deep aquifer systems. This regional study examines data on shallow ground-water quality collected from 1993 to 2004 from 273 agricultural and 181 urban wells from 7 U.S. Geological Survey National Water-Quality Assessment study units in Arizona, California, Nevada, New Mexico, south-central Colorado, and Utah. This report determines important influences that land-use practices may have on the quality of recently recharged ground water, which may ultimately affect deep water supplies within the region.

Scientific Investigations Report↗

USGS2008

Assessing the vulnerability of public-supply wells to contamination—High Plains Aquifer near York, Nebraska

The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program found, in studies from 1991 to 2001, low levels of mixtures of contaminants in ground water near the water table in urban areas across the Nation. Although contaminants were detected less frequently in deeper ground water typically developed for public supply the proximity of contaminant mixtures to underlying public-water-supply sources prompted the NAWQA Program to begin, in 2001, an intensive study to assess the vulnerability of public-supply wells to contamination. As part of this study, the pathways and processes by which contaminants reach public-supply wells in nine aquifer systems across the country are being investigated. In addition to studying the processes that occur below land surface—whereby contaminants are mobilized or attenuated—scientists are also investigating how human activities can affect the vulnerability of public-supply wells to contamination. This fact sheet highlights findings from two reports on the vulnerability study of a single, representative public-supply well in York, Nebraska. The selected high-capacity well typically produces more than 720,000 gallons per day from the upper confined aquifer of the High Plains aquifer. A possible source of contamination to the well is intensive, irrigated agriculture, which can sometimes result in elevated concentrations of nitrate and pesticides in ground water. In addition, a sampling of the selected public-supply well by the USGS in 2002 found low concentrations of the solvents trichloroethylene (TCE), tetrachloroethylene (PCE), and their degradation products, which may be linked to historical chemical use in urban and residential areas of York. Uranium and arsenic (which occur naturally in the sediments that make up the aquifers in the area) also were detected in 2002 at concentrations less than drinking-water standards but still of concern. Overall, the current NAWQA study found that three primary factors affect the movement and fate of contaminants and the vulnerability of the public-supply well in York: (1) timing of water entry (recharge) to the aquifer, (2) short-circuiting of natural flow paths through inactive wells, and (3) natural geochemical conditions of the aquifer. Study findings are intended to help water managers, drinking-water suppliers, policymakers, and scientists to better understand how and why contamination of public-supply wells occurs and whether water quality may improve or degrade. Additionally, study findings may be used to evaluate various pumping, resource-development, and land-management scenarios.

Fact Sheet↗