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Evaluation of modeled bacteria loads along an impaired stream reach receiving discharge from a municipal separate storm sewer system in Independence, Mo.

The Little Blue River in Jackson County, Missouri, was listed as impaired in 2012 due to Escherichia coli ( E. coli ) from urban runoff and storm sewers. A study was initiated to characterize E. coli concentrations and loads to aid in the development of a total maximum daily load implementation plan. Longitudinal sampling along the stream revealed spatial and temporal variability in E. coli loads. Regression models were developed to better represent E. coli variability in the impaired reach using continuous hydrologic and water-quality parameters as predictive parameters. Daily loads calculated from main-stem samples were significantly higher downstream compared to upstream even though there was no significant difference between the upstream and downstream measured concentrations and no significant conclusions could be drawn from model-estimated loads due to model-associated uncertainty. Increasing sample frequency could decrease the bias and increase the accuracy of the modeled results.

Missouri

Association of water arsenic with incident diabetes in U.S. adults: The Multi-Ethnic Study of Atherosclerosis and The Strong Heart Study

OBJECTIVE We examined the association of arsenic in federally regulated community water systems (CWSs) and unregulated private wells with type 2 diabetes (T2D) incidence in the Strong Heart Family Study (SHFS), a prospective study of American Indian communities, and the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective study of racially and ethnically diverse urban U.S. communities. RESEARCH DESIGN AND METHODS We evaluated 1,791 participants from SHFS and 5,777 participants from MESA who had water arsenic estimates available and were free of T2D at baseline (2001–2003 and 2000–2002, respectively). Participants were followed for incident T2D until 2010 (SHFS cohort) or 2019 (MESA cohort). We used Cox proportional hazards mixed-effects models to account for clustering by family and residential zip code, with adjustment for sex, baseline age, BMI, smoking status, and education. RESULTS T2D incidence was 24.4 cases per 1,000 person-years (mean follow-up, 5.6 years) in SHFS and 11.2 per 1,000 person-years (mean follow-up, 14.0 years) in MESA. In a meta-analysis across the SHFS and MESA cohorts, the hazard ratio (95% CI) per doubling in CWS arsenic was 1.10 (1.02, 1.18). The corresponding hazard ratio was 1.09 (0.95, 1.26) in the SHFS group and 1.10 (1.01, 1.20) in the MESA group. The corresponding hazard ratio (95% CI) for arsenic in private wells and incident T2D in SHFS was 1.05 (0.95, 1.16). We observed statistical interaction and larger magnitude hazard ratios for participants with BMI <25 kg/m 2 and female participants. CONCLUSIONS Low to moderate water arsenic levels (<10 µg/L) were associated with T2D incidence in the SHFS and MESA cohorts.

Diabetes Care

Catalog of US GeoData

The development of geographic information systems (GIS) is a rapidly growing industry that supports natural resources, studies, land management, environmental analysis, and urban and transporation planning. The increasing use of computers for storing and analyzing earth science information has greatly expanded the demand for digital cartographic and geographic data. Digital cartography involves the collection, storage, processing, analysis, and display of map data with the aid of computers. The U.S. Geological Survey (USGS), the Nation's largest earth science research agency, through its National Mapping Program, has expanded digital cartography operations to include the collection of elevation, planimetric, land use and land cover, and geographic names information in digital form. This digital information is available on 9-track magnetic tapes and, in the case of 1:2,000,000-scale planimetric digital line graph data, in Compact Disc Read Only Memory (CD-ROM) format. Digital information can be used with all types of geographic and land information systems.

General Information Product

Environmental setting and factors that affect water quality in the Georgia-Florida Coastal Plain study unit

The Georgia-Florida Coastal Plain study unit covers an area of nearly 62,000 square miles in the southeastern United States, mostly in the Coastal Plain physiographic province. Land resource provinces have been designated based on generalized soil classifications. Land resource provinces in the study area include: the Coastal Flatwoods, the Southern Coastal Plain, the Central Florida Ridge, the Sand Hills, and the Southern Piedmont. The study area includes all or parts of seven hydrologic subregions: the Ogeechee-Savannah, the Altamaha- St.Marys, the Suwannee, the Ochlockonee, the St. Johns, the Peace-Tampa Bay, and the Southern Florida. The primary source of water for public supply in the study area is ground water from the Upper Floridan aquifer. In 1990, more than 90 percent of the 2,888 million gallons per day of ground water used came from this aquifer. The population of the study area was 9.3 million in 1990. The cities of Jacksonville, Orlando, St. Petersburg, Tallahassee, and Tampa, Florida, and parts of Atlanta and Savannah, Georgia, are located in the study area. Forest and agricultural areas are the most common land uses in the study area, accounting for 48 percent and 25 percent of the study area, respectively. Climatic conditions range from temperate in Atlanta, Georgia, where mean annual temperature is about 61.3 degrees Fahrenheit, to subtropical in Tampa, Florida, where mean annual temperature is about 72.4 degrees Fahrenheit. Long-term average precipitation (1961-90) ranges from 43.9 inches per year in Tampa, Florida, and 44.6 in Macon, Georgia, to 65.7 inches per year in Tallahassee, Florida. Floods in the study area result from frontal systems, hurricanes, tropical storms, or severe thunderstorms. Droughts are not common in the study area,especially in the Florida part of the study area due to extensive maritime exposure. The primary physical and cultural characteristics in the study area include physiography, soils and land resource provinces, geologic setting, ground-water systems, surface- water systems, climate, floods, droughts, population, land use, and water use. Factors affecting water quality in the study area are land use (primarily urban and agricultural land uses), water use in coastal areas, hydrogeology, ground-water/surface-water interaction, geology, and climate. Surface-water quality problems in urban areas have occurred in the Ogeechee, Canoochee, Ocmulgee, St. Marys, Alapaha, Withlacoochee (north), Santa Fe, Ochlockonee, St. Johns, and Oklawaha Rivers and include nitrogen and phosphorus loading, low dissolved oxygen, elevated bacteria, sediment, and turbidity, and increased concentrations of metals. In agricultural areas, surface-water quality problems include elevated nitrogen and phosphorus concentrations, erosion, and sedimentation and have occurred in the Ocmulgee, St. Marys, Santa Fe, Ochlockonee, St. Johns, Oklawaha, Withlacoochee (South), Hillsborough, and Alafia Rivers. Ground water-quality problems such as saltwater intrusion have occurred mostly in coastal areas and were caused by excessive withdrawals.

Florida, Georgia

Environmental contamination and unusual snake mortality in an urban national wildlife refuge

The National Wildlife Refuge (NWR) System protects ~150 million acres of land and water in the United States and provides habitat for >2,000 native vertebrates species. Although legally protected, wildlife populations within these refuges can be threatened by anthropogenic activities. The lack of knowledge about such threats has the potential to undermine biodiversity conservation. We investigated patterns of wildlife mortality among three NWRs in the northern U.S. Gulf Coast. Visual surveys (958 total search-hours) were conducted for live or dead amphibians and reptiles at Big Branch, Bogue Chitto, and Bayou Sauvage NWRs. An exceptionally high incidence of snake mortality (>800% above background, P < 0.001) was observed at one site (Haul Road, Bayou Sauvage NWR). Mortality affected seven species and recurred for 29 months. Intact carcasses were subject to histopathological examination and diagnostic testing. Cause of death was undetermined (n = 9) or attributed to various pathogens (n = 5). To investigate possible underlying causes of this unusual mortality, water exposure challenges and soil toxicological analyses (n = 6 and 11 sites, respectively) were conducted on samples from Bayou Sauvage NWR, given the known potential for anthropogenic contamination in the refuge. In a controlled experiment, survival of Anaxyrus fowlerii embryos exposed to water from Recovery Road (i.e., 250m from a landfill) and Haul Road was reduced 92% and 48%, respectively, compared to four reference sites in the refuge. Sediment analyses suggested at least seven distinct sources of contaminants in Bayou Sauvage NWR. Potential sources included a landfill, illegal dumping, vehicle emissions, pesticide migration, and an active hydrocarbon pipeline leak discovered 600 m from Haul Road. Synthesis and applications: Although further research is needed to determine whether the observed mortality and contamination are related, these collective findings suggest that anthropogenic factors may threaten the ecological integrity of one of the United States largest urban wildlife refuges. More broadly, our study highlights the critical need for species inventories, baseline data, and systematic monitoring in NWRs. Such information is essential to detecting and mitigating anthropogenic threats to biodiversity conservation in protected areas.

Louisiana

Description and evaluation of the effects of urban and agricultural development on the surficial aquifer system, Palm Beach County, Florida

The surficial aquifer system in Palm Beach County was studied during 1982-85 to determine the effects of increased urban and agricultural development on groundwater levels, flow directions, and quality. The surficial aquifer system and its geologic matrix are divisible into three zones on the bases of relative permeabilities and lithologic characteristics. The two greatest water users in the county, public supply utilities and agricultural irrigators, increased total water withdrawals by 123 and 50%, respectively, during 1970-80. By 1980, 76% of public supply withdrawals were from zones I and II of the surficial aquifer system, whereas groundwater pumpage for irrigation decreased to 9% of the total irrigation water used. Increases in groundwater withdrawals for public supply were greatest in the southeast and central coastal parts of the county and served as an indicator for potential changes of flow directions and water quality in the surficial aquifer system. Residual seawater, emplaced in the aquifer system during the Pleistocene Epoch, is still prevalent in the central and western parts of Palm Beach County where low permeabilities in the geologic matrix have retarded its dilution. Chemical analyses of canal-water and groundwater samples collected in April 1984 were used to evaluate the effects of groundwater/surface water exchange on the quality of water during canal conveyance across the area containing residual seawater.

Florida

Efficiency of a stormwater detention pond in reducing loads of chemical and physical constituents in urban streamflow, Pinellas County, Florida

A multipurpose wet stormwater detention pond in Pinellas Park, Florida was studied to determine its effectiveness in reducing the load of selected water-quality constituents commonly found in urban streamflow. Water-quality samples, and data on streamflow and precipitation were collected at the outflow and principal inflow of detention area 3 on Saint Joe Creek. To compare the constituent loads entering and leaving the detention pond, flows and water quality were monitored simultaneously at the inflow and outflow sites for six storms, and were monitored intermittently during periods of base flow. Lodas od 19 selected chemical and physical constituents were determined. Because all the stormwater entering the detention pond was not measured at the inflow site, computed stormwater inflow loads were adjusted to account for loads from the unmonitored areas. The ratio of storm- water volume measured at the outflow site to stormwater volume measured at the inflow site was used to adjust inflow loads for individual storms. Pond efficiencies for selected water- quality constituents for each of the storms were estimated by dividing the difference in outflow and adjusted inflow loads by the adjusted inflow load. Stormwater loads of the major ions (chloride, calcium and bicarbonate) and dissolved solids at the outflow site exceeded loads at the inflow site, partly as a result of mixing with base flow stored within the pond. However, the detention pond was effective in reducing the stormwater load of such urban-runoff contaminants as metals, nutrients, suspended solids, and biochemical and chemical oxygen demand. Estimated median pond efficiencies for reducing constituent loads ranged from 25 to more than 60 percent for metals, 2 to 52 percent for nutrients, 2 to 52 percent for nutrients, 7 to 11 percent for two measurements of suspended solids, and 16 to 49 percent for the oxygen- consuming substances. The reductions of constituent loads in stormwater are probably a result of dilution with pond water (particularly for smaller storms), adsorption, chemical precipitation, settling, biologic uptake, and oxidation. The establishment of aquatic vegetation midway through the study appears to have increased the efficiency of the pond in reducing loads of urban-runoff contaminants in stormwater. The efficiency of the detention pond in reducing base-flow loads was estimated by comparing base-flow loads at the out- flow site prior to and after construction of the pond. Loads of major ions and dissolved solids in base flow were reduced at median efficiencies ranging from 17 to 35 percent. Urban-runoff con- taminants in base flow were generally reduced at higher efficiencies. Median efficiencies ranged from 38 to 82 percent for metals, 19 to 83 percent for nutrients, 34 to 45 percent for suspended solids, and 43 to 65 for the oxygen-consuming substances. The reductions in loads in base flow are probably a result of adsorption, chemical precipitation, biologic uptake, and settling within the pond. These processes were more effective in reducing base-flow loads after the establishment of aquatic vegetation in the pond.

Water-Resources Investigations Report

Statistical Approaches to Interpretation of Local, Regional, and National Highway-Runoff and Urban-Stormwater Data

Decision makers need viable methods for the interpretation of local, regional, and national-highway runoff and urban-stormwater data including flows, concentrations and loads of chemical constituents and sediment, potential effects on receiving waters, and the potential effectiveness of various best management practices (BMPs). Valid (useful for intended purposes), current, and technically defensible stormwater-runoff models are needed to interpret data collected in field studies, to support existing highway and urban-runoffplanning processes, to meet National Pollutant Discharge Elimination System (NPDES) requirements, and to provide methods for computation of Total Maximum Daily Loads (TMDLs) systematically and economically. Historically, conceptual, simulation, empirical, and statistical models of varying levels of detail, complexity, and uncertainty have been used to meet various data-quality objectives in the decision-making processes necessary for the planning, design, construction, and maintenance of highways and for other land-use applications. Water-quality simulation models attempt a detailed representation of the physical processes and mechanisms at a given site. Empirical and statistical regional water-quality assessment models provide a more general picture of water quality or changes in water quality over a region. All these modeling techniques share one common aspect-their predictive ability is poor without suitable site-specific data for calibration. To properly apply the correct model, one must understand the classification of variables, the unique characteristics of water-resources data, and the concept of population structure and analysis. Classifying variables being used to analyze data may determine which statistical methods are appropriate for data analysis. An understanding of the characteristics of water-resources data is necessary to evaluate the applicability of different statistical methods, to interpret the results of these techniques, and to use tools and techniques that account for the unique nature of water-resources data sets. Populations of data on stormwater-runoff quantity and quality are often best modeled as logarithmic transformations. Therefore, these factors need to be considered to form valid, current, and technically defensible stormwater-runoff models. Regression analysis is an accepted method for interpretation of water-resources data and for prediction of current or future conditions at sites that fit the input data model. Regression analysis is designed to provide an estimate of the average response of a system as it relates to variation in one or more known variables. To produce valid models, however, regression analysis should include visual analysis of scatterplots, an examination of the regression equation, evaluation of the method design assumptions, and regression diagnostics. A number of statistical techniques are described in the text and in the appendixes to provide information necessary to interpret data by use of appropriate methods. Uncertainty is an important part of any decisionmaking process. In order to deal with uncertainty problems, the analyst needs to know the severity of the statistical uncertainty of the methods used to predict water quality. Statistical models need to be based on information that is meaningful, representative, complete, precise, accurate, and comparable to be deemed valid, up to date, and technically supportable. To assess uncertainty in the analytical tools, the modeling methods, and the underlying data set, all of these components need be documented and communicated in an accessible format within project publications.

Open-File Report

Hydrogeologic settings and groundwater-flow simulations for regional investigations of the transport of anthropogenic and natural contaminants to public-supply wells&mdash;Investigations begun in 2004

A study of the Transport of Anthropogenic and Natural Contaminants to public-supply wells (TANC study) was begun in 2001 as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. The study was designed to shed light on factors that affect the vulnerability of groundwater and, more specifically, water from public-supply wells to contamination to provide a context for the NAWQA Program's earlier finding of mixtures of contaminants at low concentrations in groundwater near the water table in urban areas across the Nation. The TANC study has included investigations at both the regional (tens to thousands of square kilometers) and local (generally less than 25 square kilometers) scales. At the regional scale, the approach to investigation involves refining conceptual models of groundwater flow in hydrologically distinct settings and then constructing or updating a groundwater-flow model with particle tracking for each setting to help quantify regional water budgets, public-supply well contributing areas (areas contributing recharge to wells and zones of contribution for wells), and traveltimes from recharge areas to selected wells. A great deal of information about each contributing area is captured from the model output, including values for 170 variables that describe physical and (or) geochemical characteristics of the contributing areas. The information is subsequently stored in a relational database. Retrospective water-quality data from monitoring, domestic, and many of the public-supply wells, as well as data from newly collected samples at selected public-supply wells, also are stored in the database and are used with the model output to help discern the more important factors affecting vulnerability in many, if not most, settings. The study began with investigations in seven regional areas, and it benefits from being conducted as part of the NAWQA Program, in which consistent methods are used so that meaningful comparisons can be made. The hydrogeologic settings and regional-scale groundwater-flow models from the initial seven regional areas are documented in Chapter A of this U.S. Geological Survey Professional Paper. Also documented in Chapter A are the methods used to collect and compile the water-quality data, determine contributing areas of the public-supply wells, and characterize the oxidation-reduction (redox) conditions in each setting. A data dictionary for the database that was designed to enable joint storage and access to water-quality data and groundwater-flow model particle-tracking output is included as Appendix 1 of Chapter A. This chapter, Chapter B, documents modifications to the study methods and presents descriptions of two regional areas that were added to the TANC study in 2004.

Professional Paper

Will it rise or will it fall? Managing the complex effects of urbanization on base flow

Sustaining natural levels of base flow is critical to maintaining ecological function as stream catchments are urbanized. Research shows a variable response of stream base flow to urbanization, with base flow or water tables rising in some locations, falling in others, or elsewhere remaining constant. The variable baseflow response is due to the array of natural (e.g., physiographic setting and climate) and anthropogenic (e.g., urban development and infrastructure) factors that influence hydrology. Perhaps as a consequence of this complexity, few simple tools exist to assist managers to predict baseflow change in their local urban area. This paper addresses this management need by presenting a decision support tool. The tool considers the natural vulnerability of the landscape, together with aspects of urban development in predicting the likelihood and direction of baseflow change. Where the tool identifies a likely increase or decrease it guides managers toward strategies that can reduce or increase groundwater recharge, respectively. Where the tool finds an equivocal result, it suggests a detailed water balance be performed. The decision support tool is embedded within an adaptive-management framework that encourages managers to define their ecological objectives, assess the vulnerability of their ecological objectives to changes in water table height, and monitor baseflow responses to urbanization. We trial our framework using two very different case studies: Perth, Western Australia, and Baltimore, Maryland, USA. Together, these studies show how pre-development water table height, climate and geology together with aspects of urban infrastructure (e.g., stormwater practices, leaky pipes) interact such that urbanization has overall led to rising base flow (Perth) and falling base flow (Baltimore). Greater consideration of subsurface components of the water cycle will help to protect and restore the ecology of urban freshwaters.

Maryland, Western Australia

Potential impacts of future urbanization and sea level rise on Florida’s natural resources

As urban development continues to encroach into natural systems, these ecosystems experience increasing degradation to their form and function. Losses in biodiversity and ecosystem function are further compounded by changing climatic conditions. The State of Florida is known for its biodiversity but has experienced declines in species populations and habitats because of urbanization and sea level rise. These declines are particularly challenging in an economy that benefits from a multibillion-dollar income from natural resources tourism. In this study, we assessed the potential future impacts of urbanization and sea level rise on a suite of conservation targets that have been set for the State. We developed six scenarios of all combinations of intermediate and high sea level rise paired with two types of urbanization (sprawling and compact) in both 2040 and 2070 to examine the potential future threats to conservation targets in High Pine and Scrub, Coastal Uplands, and Freshwater Aquatics ecosystems. Our results show projected decreases in extent and area of these priority ecosystems into the future. Florida's current trend in urbanization practices are projected to have a greater impact on conservation targets than if sprawl reduction practices are implemented. Coastal Uplands are projected to experience the greatest loss in area, at up to 47%. Conservation-focused urban planning and climate adaptation strategies can help protect Florida's natural resources with benefits to Florida's tourism economy as well as critical ecosystem functions and services such as coastal flood protection and storm surge risk reduction.

Florida

Application of hydraulic and hydrologic data in urban stormwater management

Techniques are described for using flood-insurance study information from the Federal Insurance Administration to analyze flood plain management alternatives. A method of developing rating curves which relate flood discharge to flood elevation is explained. Graphical methods of determining urban flood discharges are used in conjunction with rating curves to develop flood profiles resulting from future urban development. The graphical techniques were compared with standard step-backwater computations for two storms and errors were less than 0.5 foot, which are well within acceptable limits.

Open-File Report

Computer Program for Point Location And Calculation of ERror (PLACER)

A program designed for point location and calculation of error (PLACER) was developed as part of the Quality Assurance Program of the Federal Highway Administration/U.S. Geological Survey (USGS) National Data and Methodology Synthesis (NDAMS) review process. The program provides a standard method to derive study-site locations from site maps in highwayrunoff, urban-runoff, and other research reports. This report provides a guide for using PLACER, documents methods used to estimate study-site locations, documents the NDAMS Study-Site Locator Form, and documents the FORTRAN code used to implement the method. PLACER is a simple program that calculates the latitude and longitude coordinates of one or more study sites plotted on a published map and estimates the uncertainty of these calculated coordinates. PLACER calculates the latitude and longitude of each study site by interpolating between the coordinates of known features and the locations of study sites using any consistent, linear, user-defined coordinate system. This program will read data entered from the computer keyboard and(or) from a formatted text file, and will write the results to the computer screen and to a text file. PLACER is readily transferable to different computers and operating systems with few (if any) modifications because it is written in standard FORTRAN. PLACER can be used to calculate study site locations in latitude and longitude, using known map coordinates or features that are identifiable in geographic information data bases such as USGS Geographic Names Information System, which is available on the World Wide Web.

Open-File Report

Direct and indirect effects of land use on floral resources and flower-visiting insects across an urban landscape

Although urban areas are often considered to have uniformly negative effects on biodiversity, cities are most accurately characterized as heterogeneous mosaics of buildings, streets, parks, and gardens that include both ‘good’ and ‘bad’ areas for wildlife. However, to date, few studies have evaluated how human impacts vary in direction and magnitude across a heterogeneous urban landscape. In this study, we assessed the distribution of floral resources and flower-visiting insects across a variety of land uses in New York City. We visited both green spaces (e.g. parks, cemeteries) and heavily developed neighborhood blocks (e.g. with high or low density residential zoning) and used structural equation modeling (SEM) to evaluate the direct and indirect effects of median income, vegetation, and development intensity on floral resources and insects in both settings. Abundance and taxonomic richness of flower-visiting insects was significantly greater in green spaces than neighborhood blocks. The SEM results indicated that heavily-developed neighborhoods generally had fewer flower-visiting insects consistent with reductions in floral resources. However, some low-density residential neighborhoods maintained high levels of floral resources and flower-visiting insects. We found that the effects of surrounding vegetation on floral resources, and thus indirect effects on insects, varied considerably between green spaces and neighborhood blocks. Along neighborhood blocks, vegetation consisted of a mosaic of open gardens and sparsely distributed trees and had a positive indirect effect on flower-visiting insects. In contrast, vegetation in urban green spaces was associated with increased canopy cover and thus had a negative indirect effect on flower-visiting insects through reductions in floral resources. In both neighborhood blocks and green spaces, vegetation had a positive direct effect on flower-visiting insects independent of the influence of vegetation on floral resources. Our results demonstrate how inter-related components of an urban ecosystem can vary with respect to one another across a heterogeneous urban landscape, suggesting that it is inappropriate to generalize about urban systems as a whole without first addressing differences among component land use types.

Oikos

Integrating fecal DNA and telemetry to estimate wildlife densities in anthropogenic landscapes

Density estimation is central to wildlife management efforts but can be challenging in anthropogenically-dominated landscapes due to small parcel sizes, access restrictions, and limited green space. Reliable density estimates are especially important for managing white-tailed deer ( Odocoileus virginianus ), whose high abundance in urbanized areas increases the need for accurate population assessments to guide management and reduce negative human–wildlife interactions. Herein, we evaluated (a) the use of a plot-based spatial capture-recapture sampling design to estimate deer density in developed landscapes and (b) if integrating telemetry data improved the precision or biological inferences of density estimates. We conducted fecal sampling at 2 study areas reflecting different characteristics of the urbanization gradient in Durham and eastern Orange counties, North Carolina: (1) rural (i.e., forested, large parcels) and (2) suburban (i.e., small parcels, limited continuous access, diversity of landscape features). We collected 223 fecal samples during a 3-week sampling period in July and September 2022, resulting in 157 individual deer detected (112 F:45 M). Rural densities were estimated at 54 deer/km 2 (95% CI = 35–84) and suburban densities at 75 deer/km 2 (95% CI = 48–117). Integrating telemetry data allowed estimation of sex-specific space use and densities, which were not possible from fecal data alone; however, precision of total density estimates was similar across integrated and fecal-only analyses. Overall, our results highlighted key trade-offs inherent to plot-based spatial capture-recapture in suburban landscapes, most notably low recapture rates, accessibility challenges to maintain optimal trap spacing, and the importance of considering auxiliary data streams as part of the study design.

North Carolina

Urbanization alters riverine fluorescent dissolved organic matter characteristics in a forested city – metropolitan Atlanta, Georgia (USA)

Streams and rivers in urban watersheds are predicted to export more bioreactive, autochthonous dissolved organic matter (DOM) relative to forested watersheds. However, the spatial and temporal variations of DOM quality in forested urban watersheds remain uncertain, and their relationships with socioeconomic conditions, biological characteristics, and the built environment are understudied. We measured optical properties of fluorescent DOM (FDOM) in 93 streams spanning a gradient of land-use and land cover during four seasons in metropolitan Atlanta, Georgia, USA. Streamwater FDOM was dominated by humic substances from anthropogenic (41%) and terrestrial origin (41.5%). Impervious surface cover was the strongest predictor, which was positively correlated with anthropogenically- and autochthonously-derived FDOM. Overwater canopy cover was positively associated with autochthonous FDOM, and housing age increased diagenetic FDOM. FDOM was more proteinaceous during low-flow conditions (fall, winter), and more allochthonous humic-like FDOM was detected during periods of higher flows (spring, summer). Interestingly, wastewater-related FDOM proxies were highest during low flows, suggesting that sewer exfiltration is a pervasive source and is diluted by other inputs during high flows. Overall, seasonal patterns in FDOM quality were associated with changes in hydrology, and FDOM was primarily humic throughout the year, a pattern likely driven by ubiquitous forest canopy cover. Our results highlight the importance of urban forests in mediating aquatic carbon cycling and provide a template for future studies that integrate sociodemographic and infrastructure information into studies of watershed biogeochemistry, especially in regions undergoing rapid, intense, and localized urban development.

Georgia

Assessment of the sand and gravel resources of the Lower Boise River Valley area, Idaho: Part one: Geological framework of the sand and gravel deposits

The USGS has undertaken a first order evaluation of sand & gravel resources in the Lower Boise River Valley in response to rapid urban expansion in the Boise-Nampa-Caldwell corridor in southwest Idaho. The study is intended to provide land-use planners and managers, particularly in the Bureau of Land Management, with a foundation of knowledge that will allow them to anticipate and plan for demand for and development of sand and gravel resources on public lands in response to the urban growth. Attributes under study include: regional geology of both alluvial source areas as well as deposits; fluvial processes that led to deposition of the sand and gravel deposits; spatial distribution of the deposits; quantity and quality of materials in the deposits; and the suitability of the deposits for a range of applications. The study will also examine and attempt to model the association between fluvial processes, deposit characteristics, and physical specifications for various applications of sand and gravel. The results will be presented in a series of sand and gravel assessment reports of which this is the first.

Idaho

Streamflow characterization and hydromodification, Indian and Kill Creek Basins, Johnson County, Kansas, 1985–2018

Urban stream restoration requires a quantitative understanding of hydromodification to provide a scientific basis for establishing, prioritizing, and monitoring stream quality improvement goals. A study by the U.S. Geological Survey, in cooperation with the Johnson County Urban stream restoration benefits from a quantitative understanding of hydromodification to provide a scientific basis for establishing, prioritizing, and monitoring stream quality improvement goals. A study by the U.S. Geological Survey, in cooperation with the Johnson County Stormwater Management Program, began in 2017 to assess streamflow conditions at U.S. Geological Survey streamgages along Indian and Kill Creeks in Johnson County, Kansas. These streams represent the most urban (Indian Creek) and least urban (Kill Creek) drainage basins in the county. The assessment used 40 streamflow indicators to characterize streamflow conditions for both streams and quantify the degree of hydromodification for Indian Creek. The 40 streamflow indicators consisted of 35 commonly used indicators for characterizing streamflow, 2 less common seasonality indicators, and 3 other indicators based on duration curves, runoff hydrographs, and streamflow percentile classes. The indicators represented five key components of the natural streamflow regime: magnitude, frequency, duration, timing, and rate of change. As part of the study, indicators were evaluated as to general utility for characterizing streamflow conditions, quantifying hydromodification, and assessing the effectiveness of implemented management practices intended to restore urban streams. Results identifying indicators that serve these purposes could be applied more generally to other streams in Johnson County to assess hydromodification and potential restoration opportunities. Although the same set of streamflow indicators may not apply to other regions, methods and results presented in this report provide guidance, techniques, and perspective for future related or similar studies elsewhere, particularly those designed to quantify hydromodification of urban streams and monitor the effectiveness of restoration efforts. Compared to Kill Creek, which, for the purposes of this study, was considered representative of a least disturbed rural reference condition, Indian Creek hydrology was determined to be substantially modified because of urbanization. Of the 35 streamflow indicators evaluated, 19 indicated a generally consistent and substantial difference between the 2 streams. Hydromodification of Indian Creek was characterized by larger annual mean and monthly mean streamflows (and, thus, larger streamflow volumes), larger low streamflows of shorter duration, larger high streamflows with increased frequency and shorter duration, faster rise and fall rates, and decreased seasonality of high and low streamflows. For the two seasonality indicators, seasonality of high and low streamflows decreased. Duration curves, runoff event hydrographs, and streamflow percentile classes also indicated differences between the two streams for specific ranges of streamflow. Indicators that were useful in identifying generally consistent and substantial differences between the two streams, and therefore demonstrating they collectively or individually may be indicators of hydromodification, included annual median and mean flows; monthly mean flows for February, July, August, September, October, November, and December; all the minimum mean flow indictors (1-day, 3-day, 7-day, 30-day, and 90-day); annual number and mean magnitude of peak flows; some of the flow pulse indicators; and rise and fall rates. Indicators determined to be marginally useful or not useful for identifying consistent and substantial streamflow differences between streams included the flashiness indicators Richards-Baker flashiness index and the fraction of the year the daily mean flow is greater than the annual mean flow, which was not expected. Municipalities are challenged by the need to restore stream quality in urbanized areas where options are limited because of existing development. Understanding hydromodification effects and implications for stream quality can help managers plan urban development that minimizes degradation of stream quality and provides insights for implementing effective management practices. Streamflow indicators identified in this report can be used to guide urban stream restoration. In particular, the most useful indicators could form the basis of numeric criteria for restoration goals aimed at achieving or progressing toward more natural streamflow conditions—and, by extension, more healthy ecosystems—by characterizing flow conditions, quantifying hydromodification, establishing stream-restoration goals, and monitoring progress toward achieving those goals as management practices are implemented.

Kansas