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At least 181 records · Page 10Linked to original sources
USGS2026

Socio-ecological impacts of the 2025 Los Angeles urban fires on communities, neighborhoods, and homes

Human settlements are increasingly being impacted by urban fires initiated by wildfires. Metrics such as area burned and number of structures destroyed are important, but research often overlooks the socio-ecological complexity of urban fires. We study the impacts of the 2025 Los Angeles fires on two communities at the neighborhood and residential parcel scales. Geospatial analyses and econometric modeling explore the relationships between urban morphology, socio-demographic factors, and home destruction. Here we show that socio-ecological characteristics and scale are key in parsing the dynamics of urban fires. Also, new socio-demographic populations are being affected and urban morphology metrics are more important than vegetation cover. Despite parallels with 19 th and early 20 th century urban conflagrations, understanding these re-emerging urban fires requires transdisciplinary approaches and unique metrics. Investigating the socio-ecological scales and dynamics of urban fires provides a valuable next step towards understanding and adapting to the risk associated with these disasters.

California↗
USGS2026

Estimating the magnitude and frequency of floods at ungaged locations on urban streams in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina, using data through the 2022 water year

In 2024, the U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, updated the methods for predicting the magnitude and frequency of floods at ungaged locations on streams in urban areas in Tennessee. The study area included 136 streamgages in urban areas in Tennessee, Mississippi, Alabama, Georgia, South Carolina, and North Carolina that had at least 10 percent developed imperviousness in their basins as indicated by data from the 2011 National Land Cover Database. Regression equations were developed to predict streamflows corresponding to the 50-​, 20-​, 10-​, 4-​, 2-​, 1-​, 0.5-​, and 0.2-​percent annual exceedance probabilities (AEPs) and were incorporated into the StreamStats application. In generalized least-​squares regression, the base-​10 logarithm of drainage area, the percentages of the streamgage basins in developed land use, and the percentages of the streamgage basins in the Piedmont and Ridge and Valley Level 3 ecoregions were statistically significant in explaining the variability in annual peak streamflows in the study area. Drainage areas ranged from 0.164 to 93.4 square miles, the percentage of the streamgage basins in developed land use ranged from 26 to 100 percent, and the percentage of the streamgage basins in Piedmont and Ridge and Valley Level 3 ecoregions ranged from 0 to 100 percent. Pseudo R-​squared values for the regression equations ranged from 0.86, or 86 percent, for the 50-​ and 20-​percent AEPs (2-​ and 5-​year floods) to 0.71, or 71 percent, for the 0.2-​percent AEP (500-​year flood). The average variance of prediction (in log base-​10 units) ranged from 0.023 for the 20-​ and 10-​percent AEPs to 0.05 for the 0.2-​percent AEP. The average variance of prediction can be reported as a percentage of the predicted value, known as the standard error of prediction, which ranged from 35.8 percent for the 20-​percent AEP (5-​year flood) to 55.4 percent for the 0.2-​percent AEP (500-​year flood). Methods are presented for estimating annual peak streamflows for gaged locations, ungaged locations on gaged streams, and locations on ungaged streams.

Alabama, Georgia, Mississippi, North Carolina, Sou↗
USGS2012

Pyrethroid insecticides in bed sediments from urban and agricultural streams across the United States

Pyrethroid insecticides are hydrophobic compounds that partition to streambed sediments and have been shown to cause toxicity to non-target organisms; their occurrence is well documented in parts of California, but there have been limited studies in other urban and agricultural areas across the United States. To broaden geographic understanding of pyrethroid distributions, bed sediment samples were collected and analyzed from 36 streams in 25 states, with about 2/3 of the sites in urban areas and 1/3 in agricultural areas. At least one pyrethroid (of the 14 included in the analysis) was detected in 78% of samples. Seven pyrethroids were detected in one or more samples. Bifenthrin was the most frequently detected (58% of samples), followed by permethrin (31%), resmethrin (17%), and cyfluthrin (14%). The other three detected pyrethroids (cyhalothrin, cypermethrin and delta/tralomethrin) were found in two or fewer of the samples. Concentrations ranged from 0.3 to 180 ng g -1 dry weight. The number of pyrethroids detected were higher in the urban samples than in the agricultural samples, but the highest concentrations of individual pyrethroids were split between urban and agricultural sites. The pyrethroids detected in the agricultural areas generally followed use patterns. Predicted toxicity was greater for urban areas and attributed to bifenthrin, cyfluthrin and cypermethrin, while in agricultural areas the toxicity was mainly attributed to bifenthrin.

Journal of Environmental Monitoring↗
USGS2012

Representation of regional urban development conditions using a watershed-based gradient study design

As part of the U.S. Geological Survey National Water-Quality Assessment Program, the effects of urbanization on stream ecosystems (EUSE) have been intensively investigated in nine metropolitan areas in the United States, including Boston, Massachusetts; Atlanta, Georgia; Birmingham, Alabama; Raleigh, North Carolina; Salt Lake City, Utah; Denver, Colorado; Dallas–Fort Worth, Texas; Portland, Oregon; and Milwaukee–Green Bay, Wisconsin. Each of the EUSE study area watersheds was associated with one ecological region of the United States. This report evaluates whether each metropolitan area can be generalized across the ecological regions (ecoregions) within which the EUSE study watersheds are located. Seven characteristics of the EUSE watersheds that affect stream ecosystems were examined to determine the similarities in the same seven characteristics of the watersheds in the entire ecoregion. Land cover (percentage developed, forest and shrubland, and herbaceous and cultivated classes), average annual temperature, average annual precipitation, average surface elevation, and average percentage slope were selected as human-influenced, climate, and topography characteristics. Three findings emerged from this comparison that have implications for the use of EUSE data in models used to predict stream ecosystem condition. One is that the predominant or "background" land-cover type (either forested or agricultural land) in each ecoregion also is the predominant land-cover type within the associated EUSE study watersheds. The second finding is that in all EUSE study areas, the watersheds account for the range of developed land conditions that exist in the corresponding ecoregion watersheds. However, six of the nine EUSE study area watersheds have significantly different distributions of developed land from the ecoregion watersheds. Finally, in seven of the nine EUSE/ecoregion comparisons, the distributions of the values of climate variables in the EUSE watersheds are different from the distributions for watersheds in the corresponding ecoregions.

Scientific Investigations Report↗
USGS2007

Response of Stream Chemistry During Base Flow to Gradients of Urbanization in Selected Locations Across the Conterminous United States, 2002-04

During 2002-2004, the U.S. Geological Survey's National Water-Quality Assessment Program conducted a study to determine the effects of urbanization on stream water quality and aquatic communities in six environmentally heterogeneous areas of the conterminous United States--Atlanta, Georgia; Raleigh-Durham, North Carolina; Milwaukee-Green Bay, Wisconsin; Dallas-Fort Worth, Texas; Denver, Colorado; and Portland, Oregon. This report compares and contrasts the response of stream chemistry during base flow to urbanization in different environmental settings and examines the relation between the exceedance of water-quality benchmarks and the level of urbanization in these areas. Chemical characteristics studied included concentrations of nutrients, dissolved pesticides, suspended sediment, sulfate, and chloride in base flow. In three study areas where the background land cover in minimally urbanized basins was predominantly forested (Atlanta, Raleigh-Durham, and Portland), urban development was associated with increased concentrations of nitrogen and total herbicides in streams. In Portland, there was evidence of mixed agricultural and urban influences at sites with 20 to 50 percent urban land cover. In two study areas where agriculture was the predominant background land cover (Milwaukee-Green Bay and Dallas-Fort Worth), concentrations of nitrogen and herbicides were flat or decreasing as urbanization increased. In Denver, which had predominantly shrub/grass as background land cover, nitrogen concentrations were only weakly related to urbanization, and total herbicide concentrations did not show any clear pattern relative to land cover - perhaps because of extensive water management in the study area. In contrast, total insecticide concentrations increased with increasing urbanization in all six study areas, likely due to high use of insecticides in urban applications and, for some study areas, the proximity of urban land cover to the sampling sites. Phosphorus concentrations increased with urbanization only in Portland; in Atlanta and Raleigh-Durham, leachate from septic tanks may have increased phosphorus concentrations in basins with minimal urban development. Concentrations of suspended sediment were only weakly associated with urbanization, probably because this study analyzed only base-flow samples, and the bulk of sediment loads to streams is transported in storm runoff rather than base flow. Sulfate and chloride concentrations increased with increasing urbanization in four study areas (Atlanta, Raleigh-Durham, Milwaukee-Green Bay, and Portland), likely due to increasing contributions from urban sources of these constituents. The weak relation between sulfate and chloride concentrations and urbanization in Dallas-Fort Worth and Denver was likely due in part to high sulfate and chloride concentrations in ground-water inflow, which would have obscured any pattern of increasing concentration with urbanization. Pesticides often were detected at multiple sites within a study area, so that the pesticide 'signature' for a given study area - the mixtures of pesticides detected, and their relative concentrations, at streams within the study area - tended to show some pesticides as dominant. The type and concentrations of the dominant pesticides varied markedly among sites within a study area. There were differences between pesticide signatures during high and low base-flow conditions in five of the six study areas. Normalization of absolute pesticide concentrations by the pesticide toxicity index (a relative index indicating potential toxicity to aquatic organisms) dramatically changed the pesticide signatures, indicating that the pesticides with the greatest potential to adversely affect cladocerans or fish were not necessarily the pesticides detected at the highest concentrations. In a screening-level assessment, measured contaminant concentrations in individual base-flow water samples were compared with various water-qual

Scientific Investigations Report↗
USGS2025

Contaminated stormwater sediment source tracking for polychlorinated biphenyls in an urban watershed of the Chesapeake Bay, United States

Fine-grained sediment in stormwater acts as a vector for persistent organic pollutants, like polychlorinated biphenyls (PCBs), through mobilization from sources within drainage areas of impacted urban watersheds. This study implemented a novel approach to identify the relative contributions of various landscape and stream sources of sediment from the Back River watershed in eastern Baltimore, Maryland, and investigated the applicability of using trace PCBs found in an urban environment as discriminants between each source type. Trace PCBs were found to be poor discriminants when identifying the relative sediment contributions of watershed-scale land use categories. When excluding PCBs in the development of a sediment fingerprinting model and instead utilizing trace elements and carbon only, sediment fingerprint modeling successfully differentiated green spaces and eroding streambanks as the most significant contributors to stormwaters sediment (37.1 % and 44.0 %, respectively) of the total sediment contributions of all considered source categories. In all samples collected from various landscape sources, storms, and cores detectable concentrations of PCBs were measured. The results of this study indicate that sediment fingerprinting may not be an effective method in predicting where PCBs may be found within an impacted watershed.

Maryland↗
USGS2018

Temporal and spatial variation in pharmaceutical concentrations in an urban river system

Many studies have quantified pharmaceuticals in the environment, few however, have incorporated detailed temporal and spatial variability due to associated costs in terms of time and materials. Here, we target 33 physico-chemically diverse pharmaceuticals in a spatiotemporal exposure study into the occurrence of pharmaceuticals in the wastewater system and the Rivers Ouse and Foss (two diverse river systems) in the city of York, UK. Removal rates in two of the WWTPs sampled (a conventional activated sludge (CAS) and trickling filter plant) ranged from not eliminated (carbamazepine) to >99% (paracetamol). Data comparisons indicate that pharmaceutical exposures in river systems are highly variable regionally, in part due to variability in prescribing practices, hydrology, wastewater management, and urbanisation and that select annual median pharmaceutical concentrations observed in this study were higher than those previously observed in the European Union and Asia thus far. Significant spatial variability was found between all sites in both river systems, while seasonal variability was significant for 86% and 50% of compounds in the River Foss and Ouse, respectively. Seasonal variations in flow, in-stream attenuation, usage and septic effluent releases are suspected drivers behind some of the observed temporal exposure variability. When the data were used to evaluate a simple environmental exposure model for pharmaceuticals, mean ratios of predicted environmental concentrations (PECs), obtained using the model, to measured environmental concentrations (MECs) were 0.51 and 0.04 for the River Foss and River Ouse, respectively. Such PEC/MEC ratios indicate that the model underestimates actual concentrations in both river systems, but to a much greater extent in the larger River Ouse.

River Foss, River Ouse↗
USGS1996

Occurrence of the gasoline oxygenate MTBE and BTEX compounds in urban stormwater in the United States, 1991-95

Methyl tert -butyl ether (MTBE) is a gasoline oxygenate. Oxygenates such as MTBE, when added to gasoline, increase the gasoline's oxygen level and decrease vehicular carbon monoxide emissions and ozone levels in the atmosphere. MTBE disperses rapidly in water, was the second most frequently detected volatile organic compound (VOC) in a study of shallow urban ground water, and is less biodegradable than common gasoline compounds, such as benzene, toluene, ethylbenzene, and total xylene (BTEX). Urban Stormwater is a possible source of MTBE found in shallow ground water. The U.S. Geological Survey (USGS) sampled stormwater in 16 cities and metropolitan areas that are required to obtain permits to discharge Stormwater from their municipal storm-sewer system into surface water. Concentrations of 62 VOCs, including MTBE and BTEX compounds, were measured in 592 Stormwater samples collected in these cities and metropolitan areas from 1991 through 1995. Concentration data for MTBE and BTEX compounds in stormwater were compiled and analyzed, and the findings are summarized in this report. This effort was part of an interagency assessment of the scientific basis and effectiveness of the Nation's oxygenated fuel program and was coordinated by the Office of Science and Technology Policy, Executive Office of the President. MTBE was the seventh most frequently detected VOC in urban Stormwater, following toluene, total xylene, chloroform, total trimethylbenzene, tetrachloroethene, and naphthalene. MTBE was detected in 6.9 percent (41 of 592) of Stormwater samples collected. When detected, concentrations of MTBE ranged from 0.2 to 8.7 micrograms per liter (µg/L), with a median of 1.5 µg/L. All detections of MTBE were less than the lower limit of the U.S. Environmental Protection Agency (EPA) draft lifetime health advisory (20 µg/L) for drinking water. Eighty-three percent of all detections of MTBE in Stormwater were in samples collected during the October through March season of each year (1991-95), which corresponds with the expected seasonal use of oxygenated gasoline in areas where carbon monoxide exceeds established air-quality standards. The median concentration of MTBE and benzene for all samples was statistically different and higher in samples collected during the October through March season than samples collected during the April through September season. Sixty-six percent of all MTBE detections occurred with BTEX compounds, and a proportionate increase in concentrations was found when these compounds occurred together. The proportionate increase could indicate a common source of MTBE and BTEX for those samples. Toluene and total xylene were the most frequently detected BTEX compounds and the most frequently detected VOCs in these investigations. Detected concentrations of toluene and total xylene ranged from 0.2 to 6.6 µg/L and 0.2 to 15 µg/L with median concentrations of 0.3 and 0.4 iig/L, respectively

Water-Resources Investigations Report↗
USGS2016

Estimation of peak discharge quantiles for selected annual exceedance probabilities in northeastern Illinois

This report provides two sets of equations for estimating peak discharge quantiles at annual exceedance probabilities (AEPs) of 0.50, 0.20, 0.10, 0.04, 0.02, 0.01, 0.005, and 0.002 (recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively) for watersheds in Illinois based on annual maximum peak discharge data from 117 watersheds in and near northeastern Illinois. One set of equations was developed through a temporal analysis with a two-step least squares-quantile regression technique that measures the average effect of changes in the urbanization of the watersheds used in the study. The resulting equations can be used to adjust rural peak discharge quantiles for the effect of urbanization, and in this study the equations also were used to adjust the annual maximum peak discharges from the study watersheds to 2010 urbanization conditions. The other set of equations was developed by a spatial analysis. This analysis used generalized least-squares regression to fit the peak discharge quantiles computed from the urbanization-adjusted annual maximum peak discharges from the study watersheds to drainage-basin characteristics. The peak discharge quantiles were computed by using the Expected Moments Algorithm following the removal of potentially influential low floods defined by a multiple Grubbs-Beck test. To improve the quantile estimates, regional skew coefficients were obtained from a newly developed regional skew model in which the skew increases with the urbanized land use fraction. The skew coefficient values for each streamgage were then computed as the variance-weighted average of at-site and regional skew coefficients. The drainage-basin characteristics used as explanatory variables in the spatial analysis include drainage area, the fraction of developed land, the fraction of land with poorly drained soils or likely water, and the basin slope estimated as the ratio of the basin relief to basin perimeter. This report also provides the following: (1) examples to illustrate the use of the spatial and urbanization-adjustment equations for estimating peak discharge quantiles at ungaged sites and to improve flood-quantile estimates at and near a gaged site; (2) the urbanization-adjusted annual maximum peak discharges and peak discharge quantile estimates at streamgages from 181 watersheds including the 117 study watersheds and 64 additional watersheds in the study region that were originally considered for use in the study but later deemed to be redundant. The urbanization-adjustment equations, spatial regression equations, and peak discharge quantile estimates developed in this study will be made available in the web application StreamStats, which provides automated regression-equation solutions for user-selected stream locations. Figures and tables comparing the observed and urbanization-adjusted annual maximum peak discharge records by streamgage are provided at https://doi.org/10.3133/sir20165050 for download.

Illinois↗
USGS2014

Wildlife friendly roads: the impacts of roads on wildlife in urban areas and potential remedies

Roads are one of the most important factors affecting the ability of wildlife to live and move within an urban area. Roads physically replace wildlife habitat and often reduce habitat quality nearby, fragment the remaining habitat, and cause increased mortality through vehicle collisions. Much ecological research on roads has focused on whether animals are successfully crossing roads, or if the road is a barrier to wildlife movement, gene flow, or functional connectivity. Roads can alter survival and reproduction for wildlife, even among species such as birds that cross roads easily. Here we examine the suite of potential impacts of roads on wildlife, but we focus particularly on urban settings. We report on studies, both in the literature and from our own experience, that have addressed wildlife and roads in urban landscapes. Although road ecology is a growing field of study, relatively little of this research, and relatively few mitigation projects, have been done in urban landscapes. We also draw from the available science on road impacts in rural areas when urban case studies have not fully addressed key topics.

Book chapter↗
USGS2007

Use of chemical analysis and assays of semipermeable membrane devices extracts to assess the response of bioavailable organic pollutants in streams to urbanization in six metropolitan areas of the United States

Studies to assess the effects of urbanization on stream ecosystems are being conducted as part of the U.S. Geological Survey’s National Water-Quality Assessment (NAWQA) Program. The overall objectives of these studies are to (1) determine how hydrologic, geomorphic, water quality, habitat, and biological characteristics respond to land-use changes associated with urbanization in specific environmental settings, and (2) compare these responses across environmental settings. As part of an integrated assessment, semipermeable membrane devices (SPMDs) were deployed in streams along a gradient of urban land-use intensity in and around Atlanta, Georgia; Raleigh-Durham, North Carolina; and Denver-Fort Collins, Colorado, in 2003; and Dallas-Fort Worth, Texas; Milwaukee-Green Bay, Wisconsin; and Portland, Oregon, in 2004. Sites were selected to avoid point-source discharge and to minimize natural variability within each of the six metropolitan areas. In addition to standard chemical analysis for hydrophobic organic contaminants, three assays were used to address mixtures and potential toxicity: (1) Fluoroscan provides an estimate of the total concentration of polycyclic aromatic hydrocarbons (PAHs); (2) the P450RGS assay indicates the presence and levels of aryl hydrocarbon receptor agonists; and (3) Microtox® measures toxicological effects on photo-luminescent bacteria. Of the 140 compounds targeted or identified by gas chromatography/mass spectrometry analysis in this study, 67 were not detected. In terms of numbers and types of compounds, the following were detected: 2 wood preservatives, 6 insecticides (parent compounds), 5 herbicides, 22 polycyclic aromatic hydrocarbons, 2 dibenzofurans, 4 polychlorinated biphenyls, 7 compounds associated with fragrances or personal care products, 4 steroids associated with wastewater, 5 polydibromated diphenyl ethers (flame retardants), 3 plasticizers, 3 antimicrobials/disinfectants, and 3 detergent metabolites. Of the 73 compounds detected and three assays utilized, 29 were detected in 25 percent or more of the streams and were strongly related to increases in urban intensity (defined as having a Spearman’s rho > 0.5 with percent urban land cover) in at least one of the six metropolitan areas investigated. These 29 endpoints included 16 PAHs, a wood preservative (pentachloroanisole), 2 insecticides (chlorpyrifos and chlordane), 3 herbicides (benfluralin, trifluralin, and dacthal), a synthetic musk (hexahydrohexamethylcyclopentabenzopyran, HHCB), 2 furans (methyldibenzofuran and benzo[b]naphtho[2,3-d]furan), and a flame retardant (BDE 47). In addition, the number of compounds detected and results of the Fluoroscan and P450RGS assays were strongly related to urban intensity. Average water concentrations estimated from SPMDs were compared to screening benchmarks for the protection of human health and aquatic life; of the 14 compounds with available benchmarks, 3 compounds (anthracene, dieldrin, and diazinon) exceeded those levels in one or more streams. Both dieldrin and anthracene exceeded their respective benchmarks in seven streams, and diazinon in only one stream. There were more exceedances in Milwaukee-Green Bay and Raleigh-Durham than in the other metropolitan areas, and there were no exceedances in Dallas-Fort Worth. The six metropolitan areas studied differed in the number and types of endpoints related to urban intensity, probably from a combination of factors governing source strength, transport, and fate of hydrophobic compounds. The number of endpoints strongly related to urban intensity ranged from 3 in Dallas-Fort Worth and Portland to 21 in Raleigh-Durham. High frequencies of detection and strong correlations with urban land cover for pyrogenic PAHs (such as unsubstituted 4-ringed PAHs) in all six metropolitan areas indicate that these compounds are an important component of urbanization, regardless of location. Pentachloroanisole, dibenzofurans, and petrogenic PAHs (alkylated PAHs and heterocyclic dibenzothiophenes) were frequently detected and strongly related to urban intensity in Atlanta, Raleigh-Durham, Milwaukee-Green Bay, and Denver-Fort Collins. Two insecticides were related to urban intensity: chlorpyrifos in Atlanta, Raleigh-Durham, and Dallas-Fort Worth; and chlordane in Raleigh-Durham. Three herbicides were strongly related to urban intensity: trifluralin in Atlanta and Raleigh-Durham; benfluralin in Atlanta, and dacthal in Denver-Fort Collins. The detection frequencies for most wastewater indicator compounds were too low to establish relations with urban intensity. Of the wastewater compounds analyzed, HHCB in Raleigh-Durham and Denver-Fort Collins, and BDE 47 in Denver-Fort Collins and Dallas-Forth Worth, had the strongest relations with urban intensity. In addition to pyrogenic PAHs, levels of aryl hydrocarbon receptor agonists (as measured by the P450RGS assay) were strongly related to increasing urban intensity in all six metropolitan areas. PAHs were the only group of aryl hydrocarbon agonists consistently detected and related with urban intensity in all six metropolitan areas. It is unknown which compounds in the SPMDs caused the increased response in the P450RGS assay because the SPMDs likely contained many aryl hydrocarbon receptor agonists not quantified by chemical analysis. It is clear that bioavailable, aryl hydrocarbon receptor agonists increase in streams with increasing urban intensity in the basin. Potential toxicity mediated by this metabolic pathway should be considered in integrated assessments of the response of aquatic biota to urbanization.

Scientific Investigations Report↗
USGS2015

Mark-recapture and mark-resight methods for estimating abundance with remote cameras: a carnivore case study

Abundance estimation of carnivore populations is difficult and has prompted the use of non-invasive detection methods, such as remotely-triggered cameras, to collect data. To analyze photo data, studies focusing on carnivores with unique pelage patterns have utilized a mark-recapture framework and studies of carnivores without unique pelage patterns have used a mark-resight framework. We compared mark-resight and mark-recapture estimation methods to estimate bobcat ( Lynx rufus ) population sizes, which motivated the development of a new "hybrid" mark-resight model as an alternative to traditional methods. We deployed a sampling grid of 30 cameras throughout the urban southern California study area. Additionally, we physically captured and marked a subset of the bobcat population with GPS telemetry collars. Since we could identify individual bobcats with photos of unique pelage patterns and a subset of the population was physically marked, we were able to use traditional mark-recapture and mark-resight methods, as well as the new “hybrid” mark-resight model we developed to estimate bobcat abundance. We recorded 109 bobcat photos during 4,669 camera nights and physically marked 27 bobcats with GPS telemetry collars. Abundance estimates produced by the traditional mark-recapture, traditional mark-resight, and “hybrid” mark-resight methods were similar, however precision differed depending on the models used. Traditional mark-recapture and mark-resight estimates were relatively imprecise with percent confidence interval lengths exceeding 100% of point estimates. Hybrid mark-resight models produced better precision with percent confidence intervals not exceeding 57%. The increased precision of the hybrid mark-resight method stems from utilizing the complete encounter histories of physically marked individuals (including those never detected by a camera trap) and the encounter histories of naturally marked individuals detected at camera traps. This new estimator may be particularly useful for estimating abundance of uniquely identifiable species that are difficult to sample using camera traps alone.

California↗
USGS2016

An assessment of mercury in estuarine sediment and tissue in Southern New Jersey using public domain data

Mercury (Hg) is considered a contaminant of global concern for coastal environments due to its toxicity, widespread occurrence in sediment, and bioaccumulation in tissue. Coastal New Jersey, USA, is characterized by shallow bays and wetlands that provide critical habitat for wildlife but share space with expanding urban landscapes. This study was designed as an assessment of the magnitude and distribution of Hg in coastal New Jersey sediments and critical species using publicly available data to highlight potential data gaps. Mercury concentrations in estuary sediments can exceed 2 μg/g and correlate with concentrations of other metals. Based on existing data, the concentrations of Hg in mussels in southern New Jersey are comparable to those observed in other urbanized Atlantic Coast estuaries. Lack of methylmercury data for sediments, other media, and tissues are data gaps needing to be filled for a clearer understanding of the impacts of Hg inputs to the ecosystem.

New Jersey↗
USGS1984

Runoff, sediment transport, and water quality in a northern Illinois agricultural watershed before urban development, 1979-81

A study designed to quantify and evaluate changes in runoff and sediment transport attributable to construction activities during urban development of a watershed required identification of pre-construction hydrologic conditions. Data collected before construction on a 2.81 sq m (7.28 sq km) agricultural watershed (upper Spring Creek) near Rockford, IL, show that during a 2-year period ending June 30, 1981, 2,890 tons (2,620 Mg) of suspended sediment were transported from the watershed. Of the 2 ,890 tons (2,620 Mg), 2,690 tons (2,440 Mg) or 93.1 % were transported during a storm in a 46.6-hour period of June 13-14, 1981. Runoff from a 0.031 sq m (0.080 sq km) subbasin (Spring Creek tributary) transported 33.9 tons (30.9 Mg) of suspended sediment during a 3.2-hour storm period on June 13, 1981. Regression models relating storm suspended-sediment yields and peak-water discharge per square mile for upper Spring Creek and Spring Creek tributary have average standard errors of 57 and 24 %, respectively. Trace amounts of currently banned pesticides, including Aldrin and DDT, were detected in streambed material samples. Documented sediment yields, chemical quality, and relations between runoff and sediment discharge provide baseline information for future evaluation of hydrologic conditions in the watershed. (USGS)

Water-Resources Investigations Report↗
USGS2023

Examining terrestrial and subterranean sediment sources and transport processes in an urban sewershed with an entirely buried stream network, Washington, D.C., United States

Excessive fine-grained sediment runoff due to anthropogenic activities is a major environmental concern for watersheds worldwide, especially so for urban areas such as Washington, D.C. Dated grey infrastructure, i.e., the network of buried pipes and reservoirs managing water resources, can amplify existing issues with sediment runoff and associated pollutants. This infrastructure, which is generally designed to quickly transport stormwaters away from urban areas, contributes to urban stream syndrome. Recent studies have suggested aging subterranean infrastructure may be an unaccounted-for source of sediments. The composition of this possible sediment source, and the extent to which it contributes to urban sediment runoff, is poorly understood. Our study seeks to examine sediment sources and transport processes in an urban watershed with an entirely buried drainage network using sediment fingerprinting, with specific attention paid to differentiating between terrestrial and subterranean sources. We demonstrate here multiple novel approaches to sampling subterranean sources including augering and entering the buried drainage network itself. The results of this study may inform sediment managers and infrastructure engineers and allow for targeted sediment reduction responses.

District of Columbia↗
USGS2016

Projected gains and losses of wildlife habitat from bioenergy-induced landscape change

Domestic and foreign renewable energy targets and financial incentives have increased demand for woody biomass and bioenergy in the southeastern United States. This demand is expected to be met through purpose-grown agricultural bioenergy crops, short-rotation tree plantations, thinning and harvest of planted and natural forests, and forest harvest residues. With results from a forest economics model, spatially explicit state-and-transition simulation models, and species–habitat models, we projected change in habitat amount for 16 wildlife species caused by meeting a renewable fuel target and expected demand for wood pellets in North Carolina, USA. We projected changes over 40 years under a baseline ‘business-as-usual’ scenario without bioenergy production and five scenarios with unique feedstock portfolios. Bioenergy demand had potential to influence trends in habitat availability for some species in our study area. We found variation in impacts among species, and no scenario was the ‘best’ or ‘worst’ across all species. Our models projected that shrub-associated species would gain habitat under some scenarios because of increases in the amount of regenerating forests on the landscape, while species restricted to mature forests would lose habitat. Some forest species could also lose habitat from the conversion of forests on marginal soils to purpose-grown feedstocks. The conversion of agricultural lands on marginal soils to purpose-grown feedstocks increased habitat losses for one species with strong associations with pasture, which is being lost to urbanization in our study region. Our results indicate that landscape-scale impacts on wildlife habitat will vary among species and depend upon the bioenergy feedstock portfolio. Therefore, decisions about bioenergy and wildlife will likely involve trade-offs among wildlife species, and the choice of focal species is likely to affect the results of landscape-scale assessments. We offer general principals to consider when crafting lists of focal species for bioenergy impact assessments at the landscape scale.

GCB Bioenergy↗
USGS1961

Urban growth and the water regimen

The continuing growth and concentration of population and industry in urban and suburban areas in recent decades has caused a complex merging of social, economic, and physical problems, The interrelationships of man and his use and development of the land and water resources is a particularly significant aspect of urbanization, but there has been relatively little study to date of the effect of urban man upon natural hydrologic conditions. As urban man changes an area from one of field and forest to one of buildings and streets, he covers land where water once entered the soil, and thus creates or aggravates problems of drainage, including storm-water runoff. As he requires increasing amounts of water for home and factory, he drills deeper wells, and builds longer aqueducts and larger dams and reservoirs. As he disposes of un- wanted waste materials, he either treats them by using water or pollutes the receiving body of water. As he dredges and deepens coastal streams carrying salt water, and he pumps greater quantities of water from wells in coastal areas, he increases the likelihood of salt-water contamination. These and many other urban effects upon hydrology deserve increasing study if we are to provide for the best use of the water and land resources available to the Nation's urban centers.

Water Supply Paper↗
USGS2007

Concentration, UV-spectroscopic characteristics and fractionation of DOC in stormflow from an urban stream, Southern California, USA

The composition of dissolved organic carbon (DOC) in stormflow from urban areas has been greatly altered, both directly and indirectly, by human activities and there is concern that there may be public health issues associated with DOC, which has unknown composition from different sources within urban watersheds. This study evaluated changes in the concentration and composition of DOC in stormflow in the Santa Ana River and its tributaries between 1995 and 2004 using a simplified approach based on the differences in the optical properties of DOC and using operationally defined differences in molecular weight and solubility. The data show changes in the composition of DOC in stormflow during the rainy season and differences associated with runoff from different parts of the basin, including extensive upland areas burned prior to the 2004 rainy season. Samples were collected from the Santa Ana River, which drains ~6950 km 2 of the densely populated coastal area of southern California, during 23 stormflows between 1995 and 2004. Dissolved organic carbon (DOC) concentrations during the first stormflows of the ‘winter’ (November to March) rainy season increased rapidly with streamflow and were positively correlated with increased faecal indicator bacteria concentrations. DOC concentrations were not correlated with streamflow or with other constituents during stormflows later in the rainy season and DOC had increasing UV absorbance per unit carbon as the rainy season progressed. DOC concentrations in stormflow from an urban drain tributary to the river also increased during stormflow and were greater than concentrations in the river. DOC concentrations in stormflow from a tributary stream, draining urban and agricultural land that contained more than 320 000 animals, mostly dairy cows, were higher than concentrations in stormflow from the river and from the urban drain. Fires that burned large areas of the basin before the 2004 rainy season did not increase DOC concentrations in the river during stormflow after the fires – possibly because the large watershed of the river damped the effect of the fires. However, the fires increased the hydrophobic neutral organic carbon fraction of DOC in stormflow from the urban drain and the tributary stream.

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