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USGS2023

Informing ASR treatment practices in a Florida aquifer through a human health risk approach

Aquifer storage and recovery (ASR) can augment water supplies and hydrologic flows under varying climatic conditions. However, imposing drinking water regulations on ASR practices, including pre-treatment before injection into the aquifer, remains arguable. Microbial inactivation data— Escherichia coli , Pseudomonas aeruginosa , poliovirus type 1 and Cryptosporidium parvum —were used in a human health risk assessment to identify how the storage time of recharged water in the Floridan Aquifer enhances pathogen inactivation, thereby mitigating the human health risks associated with ingestion. We used a quantitative microbial risk assessment to evaluate the risks for a gastrointestinal infection (GI) and the associated disability-adjusted life years (DALYs) per person per year. The risk of developing a GI infection for drinking water no longer exceeded the suggested annual risk threshold (1 × 10 −4 ) by days 31, 1, 52 and 80 for each pathogen, respectively. DALYs per person per year no longer exceeded the World Health Organization threshold (1 × 10 −6 ) by days 27, <1, 43 and 72. In summary, storage time in the aquifer yields a significant reduction in health risk. The findings emphasize that considering microbial inactivation, caused by storage time and geochemical conditions within ASR storage zones, is critical for recharge water treatment processes.

Florida↗

USGS2016

Recreation, values and stewardship: Rethinking why people engage in environmental behaviors in parks and protected areas

Successfully promoting and encouraging the adoption of environmental stewardship behavior is an important responsibility for public land management agencies. Although people increasingly report high levels of concern about environmental issues, widespread patterns of stewardship behavior have not followed suit (Moore 2002). One concept that can be applied in social science research to explain behavior change is that of values. More specifically, held and assigned values lie at the heart of understanding why people around the world continue to live in unsustainable ways that impact parks and protected areas. A held value is an individual psychological orientation defined by Rokeach as “an enduring belief that a specific mode of conduct or endstate of existence is personally and socially preferable” (1973, 550). Held values are at the core of human cognition, and as such, influence attitudes and behavior. Assigned values on the other hand, according to Brown (1984), are the perceived qualities of an environment that are based on and deduced from held values. In other words, assigned values are considered the material and nonmaterial benefits that people believe they obtain from ecosystems. Held and assigned values predict stewardship behaviors (Figure 1). During the 2013 George Wright Society Conference on Parks, Protected Areas, and Cultural Sites, we organized a session to improve our understanding of why individuals and groups choose to engage in stewardship behaviors that benefit the environment. We used held and assigned values as vehicles to explore what people cared about in diverse landscapes, review select case studies from across the globe, and question how best to incorporate visitor perspectives into protected area management decisions and policymaking. In addition to sharing project results, we also discussed the importance of accounting for multiple and often competing value perspectives, potential ways to integrate disciplinary perspectives on valuing nature, and future directions for social science research and practice. In this paper, we present the results from our session to provide fodder for further contemplation about the timely question of how park and protected area managers can foster values that lead to environmental protection.

Book chapter↗

USGS1996

Environmental setting of benchmark streams in agricultural areas of eastern Wisconsin

This report describes the environmental setting of 20 benchmark streams in agricultural areas of eastern Wisconsin that are part of the Western Lake Michigan Drainages, National Water-Quality Assessment Program. Benchmark streams are defined as those that show minimal adverse effects from human activity, and they were selected on the basis of field reconnaissance and the following criteria: (1) available invertebrate or fisheries data that indicated good to excellent water quality, (2) instream habitat restoration for fisheries enhancement, and (3) land management to protect riparian vegetation. Information gathered from these benchmark sites can be used as a standard of reference to compare the health of other streams in agricultural areas on the basis of aquatic-biota communities, habitat, and water-quality characteristics. The information included in this report serves as background information that will be useful for a series of studies at these benchmark-stream sites in the Western Lake Michigan Drainages study unit as part of the National Water-Quality Assessment Program. Four relatively homogeneous units (RHU's) in agricultural areas that differed in bedrock and surficial geology were selected for study. RHU 1 (clayey surficial deposits over carbonate bedrock) and RHU 3 (sandy-till surficial deposits over carbonate bedrock) are in adjacent agricultural areas in the Southeastern Wisconsin Till Plains ecoregion. RHU 20 (sandy/sand and gravel surficial deposits over igneous and metamorphic bedrock) and RHU 26 (sandy/sand and gravel surficial deposits over sandstone bedrock) are in adjacent areas of agriculture and mixed forests in the North Central Hardwood Forests ecoregion. Differences in land use/land cover, and riparian vegetation and instream habitat characteristics are presented. Summaries of field measurements of water temperature, pH, specific conductance and concentrations of dissolved oxygen, total organic plus ammonia nitrogen, dissolved ammonium, nitrate plus nitrte as nitrogen, total phosphorus, dissolved orthophosphate, and atrazine are listed. Concentrations of dissolved oxygen for the sampled streams ranged from 6 A to 14.3 and met the standards set by the Wisconsin Department of Natural Resources (WDNR) for supporting fish and aquatic life. Specific conductance ranged from 98 to 753 u,Scm with values highest in RHU's 1 and 3, where streams are underlain by carbonate bedrock. Median pH did not vary greatly among the four RHU's and ranged from 6.7 to 8.8 also meeting the WDNR standards. Concentrations of total organic plus ammonia nitrogen, dissolved ammonium, total phosphorus, and dissolved orthophosphate show little variation between streams and are generally low, compared to concentrations measured in agriculturally-affected streams in the same RHU's during the same sampling period. Concentrations of the most commonly used pesticide in the study unit, atrazine, were low in all streams, and most concentrations were below trn 0.1 u,g/L detection limit. Riparian vegetation for the benchmark streams were characterized by lowland species of the native plant communities described by John T. Curtis in the "Vegetation of Wisconsin." Based on the environmental setting and water-quality information collected to date, these streams appear to show minimal adverse effects from human activity.

Wisconsin↗

USGS2007

Restoration of mangrove plantations and colonisation by native species in Leizhou bay, South China

To examine the natural colonisation of native mangrove species into remediated exotic mangrove stands in Leizhou Bay, South China, we compared soil physical-chemical properties, community structure and recruitments of barren mangrove areas, native mangrove species plantations, and exotic mangrove species-Sonneratia apetala Buch.Ham-between plantations and natural forest. We found that severely degraded mangrove stands could not regenerate naturally without human intervention due to severely altered local environments, whereas some native species had been recruited into the 4-10 year S. apetala plantations. In the first 10 years, the exotic species S. apetala grew better than native species such as Rhizophora stylosa Griff and Kandelia candel (Linn.) Druce. The mangrove plantation gradually affected soil physical and chemical properties during its recovery. The exotic S. apetala was more competitive than native species and its plantation was able to restore soil organic matter in about 14 years. Thus, S. apetala can be considered as a pioneer species to improve degraded habitats to facilitate recolonisation by native mangrove species. However, removal to control proliferation may be needed at late stages to facilitate growth of native species. To ensure sustainability of mangroves in South China, the existing mangrove wetlands must be managed as an ecosystem, with long-term scientific monitoring program in place. ?? 2007 The Ecological Society of Japan.

Ecological Research↗

USGS2009

Probability of Elevated Nitrate Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

This raster data set delineates the predicted probability of elevated nitrate concentrations in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps was developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

Data Series↗

USGS2009

Probability of Unmixed Young Groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

This raster data set delineates the predicted probability of unmixed young groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps were developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

Data Series↗

USGS2006

Occurrence of anthropogenic organic compounds in ground water and finished water of community water systems in Eagle and Spanish Springs Valleys, Nevada, 2002-2004

As a part of the U.S. Geological Survey's National Water-Quality Assessment Program, an effort to characterize the quality of major rivers and aquifers used as a source of supply to some of the largest community water systems (CWSs) in the United States has been initiated. These studies, termed Source Water-Quality Assessments (SWQAs), consist of two sampling phases. Phase 1 was designed to determine the frequency of detection and concentrations of about 260 volatile organic compounds (VOCs), pesticides and pesticide degradates, and other anthropogenic organic compounds in source water of 15 CWS wells in each study. Phase 2 monitors concentrations in the source water and also the associated finished water of CWSs for compounds most frequently detected during phase 1. One SWQA was completed in the Nevada Basin and Range area in Nevada. Ten CWS wells in Eagle Valley and five CWS wells in Spanish Springs Valley were sampled. For phase 2, two wells were resampled in Eagle Valley. Samples were collected during 2002-2004 for both phases. Water use in Eagle Valley is primarily for domestic purposes and is supplied through CWSs. Ground-water sources provide about 55 percent of the public-water supply, and surface-water sources supply about 45 percent. Lesser amounts of water are provided by domestic wells. Very little water is used for agriculture or manufacturing. Spanish Springs Valley has water-use characteristics similar to those in Eagle Valley, although there is more agricultural water use in Spanish Springs Valley than in Eagle Valley. Maximum contaminant concentrations were compared to two human-health benchmarks, if available, to describe the water-quality data in a human-health context for these findings. Measured concentrations of regulated contaminants were compared to U.S. Environmental Protection Agency and Nevada Maximum Contaminant Level (MCL) values. Measured concentrations of unregulated contaminants were compared to Health-Based Screening Levels, which are not regulatory standards and are not legally enforceable values. All of the contaminants detected in this study were found at concentrations less than available human-health benchmarks. In the source waters sampled in phase 1, 10 contaminants of the approximately 260 measured were detected in samples collected from Eagle Valley, and 4 contaminants were detected in samples from Spanish Springs Valley. The most frequently detected compounds in the Eagle Valley source water were chloroform (a disinfection by-product), which was detected in samples from four wells, and deethylatrazine (a degradation product of the herbicide atrazine), which was detected in samples from three wells. Each of the four contaminants detected in the Spanish Springs Valley source waters was detected in samples from one well. The detection frequencies of VOCs and pesticides in samples from the SWQA wells were similar to those in samples from both shallow and deep monitoring wells in Carson City, Reno, and Spanish Springs. This indicates that the SWQA sampling is representative of the organic chemical compounds likely to be detected in the aquifers sampled. However, more organic compounds were detected at low frequencies and concentrations in samples from the monitoring wells than in samples from SWQA wells. Three contaminants were detected in one finished-water sample collected from Eagle Valley. Comparison of SWQA results in the Nevada Basin and Range Study Unit to results of an SWQA in the larger urban area of Salt Lake City showed that fewer anthropogenic compounds were detected in Eagle and Spanish Springs Valleys and generally at lower concentrations than in the Salt Lake City study.

Scientific Investigations Report↗

USGS2006

Present and Reference Concentrations and Yields of Suspended Sediment in Streams in the Great Lakes Region and Adjacent Areas

In-stream suspended sediment and siltation and downstream sedimentation are common problems in surface waters throughout the United States. The most effective way to improve surface waters impaired by sediments is to reduce the contributions from human activities rather than try to reduce loadings from natural sources. Total suspended sediment/solids (TSS) concentration data were obtained from 964 streams in the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River Basins from 1951 to 2002. These data were used to estimate median concentrations, loads, yields, and volumetrically (flow) weighted (VW) concentrations where streamflow data were available. SPAtial Regression-Tree Analysis (SPARTA) was applied to land-use-adjusted (residualized) TSS data and environmental-characteristic data to determine the natural factors that best described the distribution of median and VW TSS concentrations and yields and to delineate zones with similar natural factors affecting TSS, enabling reference or natural concentrations and yields to be estimated. Soil properties (clay and organic-matter content, erodibility, and permeability), basin slope, and land use (percentage of agriculture) were the factors most strongly related to the distribution of median and VW TSS concentrations. TSS yields were most strongly related to amount of precipitation and the resulting runoff, and secondarily to the factors related to high TSS concentrations. Reference median TSS concentrations ranged from 5 to 26 milligrams per liter (mg/L), reference median annual VW TSS concentrations ranged from 10 to 168 mg/L, and reference TSS yields ranged from about 980 to 90,000 kilograms per square kilometer per year. Independent streams (streams with no overlapping drainage areas) with TSS data were ranked by how much their water quality exceeded reference concentrations and yields. Most streams exceeding reference conditions were in the central part of the study area, where agricultural activities are the most intensive; however, other sites exceeding reference conditions were identified outside of this area. Whether concentrations or yields should be considered in guiding rehabilitation efforts depends on whether in-stream or downstream effects are more important. Although this study attempted to obtain all available water-quality data for the study area, any actual prioritization of sites for remediation would need to rely on more extensive data collection or numerical models that can accurately simulate the effects of various human activities in a range of environmental settings.

Scientific Investigations Report↗

USGS2016

Smokey comes of age: Unmanned aerial systems for fire management

During the past century, fire management has focused on techniques both to protect human communities from catastrophic wildfire and to maintain fire-dependent ecological systems. However, despite a large and increasing allocation of resources and personnel to achieve these goals, fire management objectives at regional to global scales are not being met. Current fire management techniques are clearly inadequate for the challenges faced by fire managers, and technological innovations are needed. Advances in unmanned aerial systems (UAS) technology provide opportunities for innovation in fire management and science. In many countries, fire management organizations are beginning to explore the potential of UAS for monitoring fires. We have taken the next step and developed a prototype that can precisely ignite fires as part of wildfire suppression tactics or prescribed fires (fire intentionally ignited within predetermined conditions to reduce hazardous fuels, improve habitat, or mitigate for large wildfires). We discuss the potential for these technologies to benefit fire management activities, while acknowledging the sizeable sociopolitical barriers that prevent their immediate broad application.

Frontiers in Ecology and the Environment↗

USGS2009

A water-leach procedure for estimating bioaccessibility of elements in soils from transects across the United States and Canada

An objective of the North American Soil Geochemical Landscapes Project is to provide relevant data concerning bioaccessible concentrations of elements in soil to government and other institutions undertaking environmental studies. A protocol was developed that employs a 1-g soil sample agitated overnight with 40 mL of reverse-osmosis de-ionized water for 20 h, and determination of 63 elements following three steps of centrifugation by inductively coupled plasma–atomic emission spectrometry and inductively coupled plasma–mass spectrometry the following day. Statistical summaries are presented for those 48 elements (Ag, Al, As, B, Ba, Be, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Ho, I, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, P, Pb, Pr, Rb, Re, S, Sb, Si, Sm, Sn, Sr, Tb, Ti, Tl, Tm, U, V, W, Y, Yb, Zn, Zr, and pH) for which <20% of their data were reported as below the detection limit. The resulting data set contains analyses for 161 A-horizon soils collected along two transects, one along the 38th parallel across the USA and the other from northern Manitoba to the USA–Mexico border. The spatial distribution of three selected elements (Ca, Cu, and Pb) along the two transects is discussed in this paper both as absolute amounts liberated by the leach and expressed as a percentage of the total, or near-total, amounts determined for the elements. The Ca data reflect broad trends in soil parent materials, their weathering, and subsequent soil development. Calcium concentrations are generally found to be lower in the older soils of the eastern USA. The Cu data are higher in the eastern half of the USA, correlating with soil organic C, with which it is sequestered. The Pb data exhibit little regional variability due to natural sources, but are influenced by anthropogenic sources. Based on the Pb results, the percentage water-extractable data demonstrate promise as a tool for identifying anthropogenic components. The soil–water partition (distribution) coefficients, K d s (L/kg), were determined and their relevance to estimating bioaccessible amounts of elements to soil fauna and flora is discussed. Finally, a possible link between W concentrations in human urine and water-extractable W levels in Nevada soils is discussed.

Applied Geochemistry↗

USGS2018

Desert wetlands record hydrologic variability within the Younger Dryas chronozone, Mojave Desert, USA

One of the enduring questions in the field of paleohydrology is how quickly desert wetland ecosystems responded to past episodes of abrupt climate change. Recent investigations in the Las Vegas Valley of southern Nevada have revealed that wetlands expanded and contracted on millennial and sub-millennial timescales in response to changes in climate during the late Quaternary. Here, we evaluate geologic evidence from multiple localities in the Mojave Desert and southern Great Basin that suggests the response of wetland systems to climate change is even faster, occurring at centennial, and possibly decadal, timescales. Paleowetland deposits at Dove Springs Wash, Mesquite Springs, and Little Dixie Wash, California, contain evidence of multiple wet and dry cycles in the form of organic-rich black mats, representing periods of past groundwater discharge and wet conditions, interbedded with colluvial, alluvial, and aeolian sediments, each representing dry conditions. Many of these wet-dry cycles date to within the Younger Dryas (YD) chronozone (12.9–11.7 ka), marking the first time intra -YD hydrologic variability has been documented in paleowetland deposits. Our results illustrate that desert wetland ecosystems are exceptionally sensitive to climate change and respond to climatic perturbations on timescales that are relevant to human society.

Arizona, California, Nevada↗

USGS2010

Hydrology and Ecology of Freshwater Wetlands in Central Florida - A Primer

Freshwater wetlands are an integral part of central Florida, where thousands are distributed across the landscape. However, their relatively small size and vast numbers challenge efforts to characterize them collectively as a statewide water resource. Wetlands are a dominant landscape feature in Florida; in 1996, an estimated 11.4 million acres of wetlands occupied 29 percent of the area of the State. Wetlands represent a greater percentage of the land surface in Florida than in any other state in the conterminous United States. Statewide, 90 percent of the total wetland area is freshwater wetlands and 10 percent is coastal wetlands. About 55 percent of the freshwater wetlands in Florida are forested, 25 percent are marshes and emergent wetlands, 18 percent are scrub-shrub wetlands, and the remaining 2 percent are freshwater ponds. Freshwater wetlands are distributed differently in central Florida than in other parts of the State. In the panhandle and in northern Florida, there are fewer isolated wetlands than in the central and southern parts of the State, and few of those wetlands are affected by activities such as groundwater withdrawals. In southern Florida, the vast wetlands of the Everglades and the Big Cypress Swamp blanket the landscape and form contiguous shallow expanses of water, which often exhibit slow but continuous flow toward the southwestern coast. In contrast, the wetlands of central Florida are relatively small, numerous, mostly isolated, and widely distributed. In many places, wetlands are flanked by uplands, generating a mosaic of contrasting environments-unique wildlife habitat often adjacent to dense human development. As the population of central Florida increases, the number of residents living near wetlands also increases. Living in close proximity to wetlands provides many Floridians with an increased awareness of nature and an opportunity to examine the relationship between people and wetlands. Specifically, these residents can observe how wetlands are affected by human activities. Freshwater wetlands are unique and complex ecosystems defined by characteristic properties. Wetlands usually have standing water during at least part of the year, although water depths can vary from a few inches to as much as several feet from one wetland to another. The hydrologic behavior of wetlands is influenced by drainage basin characteristics, as well as by natural variations in climate. Wetlands in central Florida (especially forested wetlands) often have acidic waters that are darkly stained from organic substances released by decomposing leaves and other plant material. Wetlands are characterized by biogeochemical cycles in which vital elements such as carbon, nitrogen, phosphorus, and others are transformed as they move between wetland soils and sediments, the open water, and the atmosphere. Wetlands are populated with plants that can thrive under conditions of saturated soils and low dissolved-oxygen concentrations. The bottoms of many wetlands, especially marshes, are covered with decayed plant material that can accumulate over time to form brown peat or black muck soils. Wetlands are inhabited by animals that need standing water to complete some or all of their life cycles, and they also provide periodic food, water, and shelter for many other animals that spend most of their lives on dry land. The complex and interrelated components of wetlands directly affect one another and there are numerous feedback mechanisms.

Circular↗

USGS2022

Sources and characteristics of dissolved organic carbon in the McKenzie River, Oregon, related to the formation of disinfection by-products in treated drinking water

Executive Summary This study characterized the concentration and quality of dissolved organic carbon (DOC) in the McKenzie River, a relatively undeveloped watershed in western Oregon, and its link to forming disinfection by-products (DBPs) in treated drinking water. The study aimed to identify the primary source(s) of DOC in source water for the Eugene Water & Electric Board’s (EWEB) conventional treatment plant on the McKenzie River near river mile 11, upstream of Hayden Bridge. The two classes of regulated compounds examined—trihalomethanes (THMs) and haloacetic acids (HAAs)—form when organic carbon in raw source water reacts with chlorine and (or) bromine during water treatment. The objectives of the study were to: characterize the amount and quality of DOC in the McKenzie River and select tributaries during storms; identify the most common types of carbon using UV-vis spectroscopy and other methods; evaluate optical properties for predicting DBP precursors in surface water; and identify land cover classes or vegetation types that may be important sources of organic carbon and DBP precursors in EWEB’s source water. Eleven storms were sampled synoptically in upstream-to-downstream fashion to provide a “snapshot” of water quality conditions at four sites on the McKenzie River from Frissell Bridge (6 miles downstream from Trail Bridge Reservoir) to the EWEB water treatment plant at Hayden Bridge and nine contributing tributaries. Storms included late summer and early autumn “first flush” events and late autumn, winter, and spring storms spanning a range in streamflows from 3,000 to 26,000 cubic feet per second as measured in the main stem McKenzie River at the EWEB water intake. Water samples were analyzed for DOC concentrations and optical properties (fluorescence and ultraviolet absorbance [UVA]) across a range of wavelengths to characterize the quantity and quality of dissolved organic matter (DOM) in the McKenzie River at the drinking water intake and upstream locations. Paired sets of source and finished water samples were collected at the EWEB treatment plant to identify DOC quality parameters in raw source water that might predict DBP concentrations in finished drinking water. DOC concentrations were relatively low in the McKenzie River (0.4–3 milligrams per liter [mg/L]; average 1.5 mg/L) but much higher in the tributaries. The highest DOC concentrations occurred during “first flush” storms in October 2012 and September 2013; the highest value (16 mg/L) was measured at the 52nd Street stormwater outfall. The average DOC concentration in the lower basin-tributaries was 3.8 mg/L; three middle basin tributaries—Quartz, Gate, and Haagen Creeks, which drain private forestland with less coniferous forest compared with other higher elevation tributaries— had slightly lower average DOC concentrations (2.8 mg/L). These middle-basin watersheds may be important sources of DOC and DBP precursors to the McKenzie River, even more so than the lower basin tributaries, depending on their flows (and loads). This is particularly true after the September 2020 Holiday Farm fire, which burned much of this area. DOC concentrations increased 68 percent in the McKenzie River between the uppermost reference site at Frissell Bridge and Vida; this includes drainage from Quartz Creek, Blue River Lake and Cougar Reservoir, which all contributed DOC to the main stem. In contrast, the lowermost tributaries draining most of the agricultural and urban land did not have a large effect on DOC in the McKenzie River despite their higher DOC concentrations because of their presumed relatively low streamflows and, consequently, DOC loads. Apart from the continuous flow monitors in the McKenzie River and some tributaries (Blue River and South Fork McKenzie River, and streamflow at Hayden Bridge and Vida, Camp Creek and some other locations), streamflow was not assessed during sample collection for this study. This lack of streamflow data precludes a detailed analysis of loads, which is discussed in the future studies section. All DBP concentrations in finished drinking water were less than EPA maximum contaminant levels (MCLs) of 0.080 mg/L for the four trihalomethanes (THM4) and 0.060 mg/L for five haloacetic acids (HAA5). During the 11 storm sampling events the maximum summed concentrations were about 0.040 mg/L for both THM4 and HAA5. Compliance monitoring samples, collected separately by EWEB, yielded some higher concentrations—0.046 mg/L THM4 and 0.047 HAA5—during the December 2012 storm. The corresponding benchmark quotient (BQ) values, which indicate how close a measured DBP concentration is to the MCL, were 0.58 and 0.78, respectively, for THM4 and HAA5. Compared with a similar 2007–08 McKenzie River study that did not target storm events, concentrations of THM4 and HAA5 in finished water were 68 percent and 33 percent higher, respectively, during the current study. Due to the high dilution rates in the McKenzie River main stem, many of the individual fluorescence excitation-emission measurements were low (<0.1 Raman units) and approached analytical detection limits. Parallel factor analysis (PARAFAC) resulted in a five-component model (C1–C5) that represents five unique organic fluorophores. Components C1, C2, and C3 represent DOM associated with soil-derived, humic-like, more degraded organic matter. In contrast, components C4 and C5 represent “fresher” DOM, derived from terrestrial and aquatic plants, including algae and cyanobacteria that are common in the McKenzie River and its tributaries and reservoirs. The fluorescence data and PARAFAC modeling suggest that most of the DOC in the McKenzie River originated from terrestrial sources (primarily components C1 and C2). The largest increases in DOC in the main stem occurred in the reach upstream of Vida, from inflows by Quartz Creek, Blue River, South Fork McKenzie River, and other tributaries. Concentrations of DBPs in EWEB’s finished drinking water were positively correlated with DOC concentrations in raw source water (THM4, p <0.05; HAA5, p <0.01) for paired samples collected 12−24 hours apart. DOC concentrations were significantly positively correlated ( p <0.001) with laboratory-based fluorescent dissolved organic matter (fDOM) measurements, suggesting fDOM as a useful parameter for monitoring and predicting DOC concentration in surface water and DBP concentrations in finished water. Of all the PARAFAC components in surface water, C5 had the highest correlations with DBPs in finished water (rho = 0.77–0.84, p <0.01), followed by components C1 and C2 (rho = 0.75 and 0.71, respectively, p <0.01). This C5 carbon is associated with recently produced DOM, possibly from decomposed terrestrial and aquatic vegetation. Model loadings of these three components were considerably higher in the sampled tributaries relative to the main stem McKenzie River, with most of the observed increases in the main stem apparent at Vida. This points to Quartz Creek or other tributaries in the reach between Frissell Bridge and the sampling site near Vida (South Fork McKenzie and Blue Rivers) as potentially key contributors of DOM source material that leads to the production of DBPs in treated drinking water. A limited load analysis showed that the reservoirs contributed 8–37 percent of the instantaneous DOC loads observed at Vida at the time of sampling, which suggests other sources such as Quartz Creek and other streams in the reach between Frissell Bridge and Vida are more important. Random forest analyses identified PARAFAC components C1 and C5 and fluorescence peaks A, C, M, T and N as the best predictors for HAA5 concentrations in finished drinking water, explaining 62.5 percent of the variation. The best predictors for THM4 were C1, C4 + C5, and peaks T, A, and N, which explained 33 percent of the variation. Several land cover and vegetation classes were correlated with DOC concentration and other optical measurements. The percentage of evergreen forest in each of the subwatersheds sampled was negatively correlated ( p <0.001) with DOC concentration and many optical indicators of DOM quantity: UVA 254 , fDOM, and all of the fluorescence peaks. In contrast, mixed (deciduous) forest was positively correlated ( p <0.001) with DOC, fDOM, UVA 254 , and several fluorescence peaks, demonstrating the importance of deciduous leaf fall in generating DOC and DBP precursors. The high level of human activities in the middle and lower portion of the basin—including timber harvesting and road construction on private forestland, agricultural, rural, industrial, and urban development—have resulted in the greatest loss in native coniferous and mixed deciduous forests in the basin. DOC loading from these tributaries and reservoir releases, which contain DOC from terrestrial and aquatic productivity, both enrich the McKenzie River. Concentrations of DOC increased an average of 71 percent (range 30–120 percent) in the McKenzie River between Frissell Bridge, the upstream reference site, and Vida. PARAFAC components C1, C2, and C5—which were correlated with DBPs in finished water—increased, on average, 109–136 percent (range 20–250 percent) in this same Frissell-to-Vida reach. These increases occur from input of tributaries in the middle basin such as Quartz Creek and others, as noted above. Future monitoring, field, and lab studies can improve our understanding of seasonal and spatial sources of organic carbon contributing DBP precursors to the McKenzie River and allow detection of long-term trends resulting from the recent Holiday Farm Fire, which burned 173,393 acres of forestland, including riparian areas along the main stem, and numerous structures, homes, and outbuildings in September 2020. Future studies could examine DOC fluxes and flushing of carbon from the watershed, investigate the role of precipitation amount and intensity in mobilizing carbon and sediment, and evaluate impacts to aquatic communities and human health as part of a post-fire assessment. Other areas ripe for study include evaluating the impacts of potential temperature increases on carbon sequestration and decomposition in the burned and unburned forests and identifying practices that foster sequestration of carbon in forest soils. The use of fluorescence sensors such as fDOM to monitor the concentration and composition of raw water supplies may be improved for detection of specific DBP precursors, to provide continuous and real-time information to treatment plant operators. Future studies that monitor DOM amount and quality, and DBP Formation Potential (FP), particularly during storm events, paired with streamflow measurements, as suggested above, could help identify areas that contribute high DOC loads and thus help managers identify the key areas to focus restoration activities. Other studies could examine treatment options for currently regulated DBPs and potentially unregulated compounds, including advanced biological treatments for their removal. This study was a collaboration between the U.S. Geological Survey (USGS) and EWEB in Eugene, Oregon, with additional funding provided from USGS Cooperative Matching Funds Program.

Oregon↗

USGS2001

U.S. Geological Survey Appalachian region integrated science workshop proceedings, Gatlinburg, Tennessee, October 22-26, 2001

Some of nature's most magnificent creations on Earth are the picturesque landscape and the terrestrial and aquatic inhabitants of the Appalachian Mountains of the Eastern United States. Mother Nature has been kind to the region but man, often, has not. The Appalachian mountains and valleys have been home to a variety of human cultures, dating back approximately 12,000 years. A series of Native American peoples, including most recently the Cherokee Nation, inhabited the region prior to European settlement which began in the 1600's. All of these peoples have had the desire to reap the benefits of the land. Current and historic use of the land ranges from mineral extraction to agricultural development to timber production to industrial and residential development, all of which have now threatened the landscape. Many individuals and organizations desire to save the awe and beauty of the Appalachians for the generations to come, in a way that is environmentally and economically sustainable. They have tried for years to raise alarms that this area is threatened and worth the attention of all who are interested in an effort of restitution and preservation. Residents, environmental groups, land managers, scientists, business groups, and the multitude of visitors who pass through the national parks and other public lands located within the Appalachians have raised these same alarms. There is a need to not only identify the issues resulting from anthropogenic pressures on the landscape, but also to collect the information and conduct the science that will allow land managers and policy makers to become better informed and better able to execute their responsibilities.

Appalachia↗

USGS2022

Using microbial source tracking to identify fecal contamination sources in Patchogue and Bellport Bays on Long Island, New York

The U.S. Geological Survey worked in cooperation with the New York State Department of Environmental Conservation to assess the potential sources of fecal contamination entering Patchogue and Bellport Bays, two embayments on the south shore of Suffolk County, Long Island, New York. Water samples are routinely collected by the New York State Department of Environmental Conservation in the bays and analyzed for fecal coliform bacteria, an indicator of fecal contamination, to determine the need for closure of shellfish beds for harvest and consumption. Fecal coliform and other bacteria are an indicator of the potential presence of pathogenic (disease-causing) bacteria. However, indicator bacteria alone cannot determine the biological or geographical sources of contamination; therefore, microbial source tracking was implemented to determine various biological sources of contamination. In addition, information such as the location, weather and season, and surrounding land use where a sample was collected help determine the geographical source and conveyance of land-based water to the embayment. Analysis revealed that the most substantial source of fecal contamination to Patchogue and Bellport Bays was discharge from sites draining ponds and wetlands into the rivers and tributaries sampled, particularly during the summer months. Fecal coliform bacteria at sites where ponds and wetlands drain are increased by stormwater runoff, which is another substantial source of fecal contamination. Overall, canine- and waterfowl-associated bacterial contributions were prevalent in source samples in both bays. Human-associated markers were present in surface-water source samples and completely absent in receptor samples in Patchogue Bay. The Fireplace Neck receptor site in Bellport Bay had a human-associated marker present in the summer wet sample only. Human markers were detected at the sample site downstream from the Patchogue wastewater treatment plant but were associated with low fecal coliform concentrations, indicating that the wastewater treatment plant is not a likely source of fecal contamination to Patchogue Bay. The lack of human-associated marker detections within Patchogue and Bellport Bays in summer source samples coupled with low to no detections of fecal coliform, especially where small marinas are present in creeks and tributaries, suggest that boats do not substantially contribute fecal coliform bacteria to the bays. There was little evidence of groundwater-contributing fecal bacteria by direct discharge from the subsurface. Further, the sandy sediment alongside Patchogue and Bellport Bays is unlikely to contribute fecal coliform bacteria from the test host organisms when resuspended in the water column. A classification scheme was developed to convey the degree of fecal contamination to stakeholders and resource managers. Based on this classification scheme, the Corey Creek Near Middle Road, Patchogue River Near Division Street, and Swan River Mouth sampling sites were identified as locations that contribute substantial fecal contamination to Patchogue Bay. In Bellport Bay, the Culvert at Beaverdam Creek site was identified as the location contributing the most substantial fecal contamination.

New York↗

USGS2015

PRMS-IV, the precipitation-runoff modeling system, version 4

Computer models that simulate the hydrologic cycle at a watershed scale facilitate assessment of variability in climate, biota, geology, and human activities on water availability and flow. This report describes an updated version of the Precipitation-Runoff Modeling System. The Precipitation-Runoff Modeling System is a deterministic, distributed-parameter, physical-process-based modeling system developed to evaluate the response of various combinations of climate and land use on streamflow and general watershed hydrology. Several new model components were developed, and all existing components were updated, to enhance performance and supportability. This report describes the history, application, concepts, organization, and mathematical formulation of the Precipitation-Runoff Modeling System and its model components. This updated version provides improvements in (1) system flexibility for integrated science, (2) verification of conservation of water during simulation, (3) methods for spatial distribution of climate boundary conditions, and (4) methods for simulation of soil-water flow and storage.

Techniques and Methods↗

USGS2024

Hepeviruses of aquatic organisms

Originally reported in California, the cutthroat trout virus (CTV) has now been isolated from nine species of salmonids in North America. Early work focused on the replication and physical characteristics of the virus, but 20 years later was determined to be most closely related to the hepatitis E virus. The small genome is positive-sense, single-stranded RNA similar to other members of the family Hepeviridae , which now contains its own genus Piscihepevirus with two distinct genotypes, CTV-1 and CTV-2. While CTV has not been associated with acute disease in fish, the virus could form persistently infected cell cultures that may aid research in treating hepatitis E-like viruses affecting humans or other animals. Interestingly, trout exposed to CTV were protected for about a month against subsequent exposure to the infectious hematopoietic necrosis virus. Replicating agents suspected to be CTV can be confirmed by polymerase chain reaction (PCR), quantitative PCR, and sequencing. Other unclassified hepeviruses detected in fish using viral metagenomics include Wenling fish hepevirus, Wenling moray eel hepevirus, Murray–Darling carp hepevirus, and eastern mosquitofish hepevirus. The family Hepeviridae has been placed in the order Hepevirales together with the family Matonaviridae (rubella virus), with member viruses having amino acid homology in the helicase and replicase regions of the nonstructural proteins. In addition, using next-generation sequencing, a hepe-like sequence was characterized in diseased giant freshwater prawn Macrobrachium rosenbergii and named Crustacea hepe-like virus 1. Thus the family Hepeviridae continues to expand among aquatic animal hosts.

Book chapter↗

USGS2004

Contemporary carbon dynamics in terrestrial ecosystems in the Southeastern Plains of the United States

Quantifying carbon dynamics over large areas is frequently hindered by the lack of consistent, high-quality, spatially explicit land use and land cover change databases and appropriate modeling techniques. In this paper, we present a generic approach to address some of these challenges. Land cover change information in the Southeastern Plains ecoregion was derived from Landsat data acquired in 1973, 1980, 1986, 1992, and 2000 within 11 randomly located 20-km × 20-km sample blocks. Carbon dynamics within each of the sample blocks was simulated using the General Ensemble Biogeochemical Modeling System (GEMS), capable of assimilating the variances and covariance of major input variables into simulations using an ensemble approach. Results indicate that urban and forest areas have been increasing, whereas agricultural land has been decreasing since 1973. Forest clear-cutting activity has intensified, more than doubling from 1973 to 2000. The Southeastern Plains has been acting as a carbon sink since 1973, with an average rate of 0.89 Mg C/ha/yr. Biomass, soil organic carbon (SOC), and harvested materials account for 56%, 34%, and 10% of the sink, respectively. However, the sink has declined continuously during the same period owing to forest aging in the northern part of the ecoregion and increased forest clear-cutting activities in the south. The relative contributions to the sink from SOC and harvested materials have increased, implying that these components deserve more study in the future. The methods developed here can be used to quantify the impacts of human management activities on the carbon cycle at landscape to global scales.

Environmental Management↗