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USGS2012

Modeling of soil erosion and sediment transport in the East River Basin in southern China

Soil erosion is a major global environmental problem that has caused many issues involving land degradation, sedimentation of waterways, ecological degradation, and nonpoint source pollution. Therefore, it is significant to understand the processes of soil erosion and sediment transport along rivers, and this can help identify the erosion prone areas and find potential measures to alleviate the environmental effects. In this study, we investigated soil erosion and identified the most seriously eroded areas in the East River Basin in southern China using a physically-based model, Soil and Water Assessment Tool (SWAT). We also introduced a classical sediment transport method (Zhang) into SWAT and compared it with the built-in Bagnold method in simulating sediment transport process along the river. The derived spatial soil erosion map and land use based erosion levels can explicitly illustrate the identification and prioritization of the critical soil erosion areas in this basin. Our results also indicate that erosion is quite sensitive to soil properties and slope. Comparison of Bagnold and Zhang methods shows that the latter can give an overall better performance especially in tracking the peak and low sediment concentrations along the river. We also found that the East River is mainly characterized by sediment deposition in most of the segments and at most times of a year. Overall, the results presented in this paper can provide decision support for watershed managers about where the best management practices (conservation measures) can be implemented effectively and at low cost. The methods we used in this study can also be of interest in sediment modeling for other basins worldwide.

Science of the Total Environment↗

USGS2015

Dreissenid mussel research priorities workshop

Currently, dreissenid mussels have yet to be detected in the northwestern part of the United States and western Canada. Infestation of one of the jurisdictions within the mussel-free Pacific Northwest would likely have significant economic, societal and environmental implications for the entire region. Understanding the biology and environmental tolerances of dreissenid mussels, and effectiveness of various management strategies, is key to prevention. On November 4-5, 2015, the Aquatic Bioinvasion Research and Policy Institute and the Center for Lakes and Reservoirs at Portland State University, the US Geological Survey, and the Pacific States Marine Fisheries Commission, convened a Dreissenid Mussel Research Priorities Workshop funded by the Great Northern Landscape Conservation Cooperative. The purpose of the workshop was to review dreissenid research priorities in the 2010 Quagga-Zebra Mussel Action Plan for Western U.S. Waters, reassess those priorities, incorporate new information and emerging trends, and develop priorities to strategically focus research efforts on zebra and quagga mussels in the Pacific Northwest and ensure that future research is focused on the highest priorities. It is important to note that there is some repetition among dreissenid research priority categories (e.g., prevention, detection, control, monitoring, and biology). Workshop participants with research experience in dreissenid mussel biology and management were identified by a literature review. State and federal agency managers were also invited to the workshop to ensure relevancy and practicality of the workshop outcomes. A total of 28 experts (see sidebar) in mussel biology, ecology, and management attended the workshop.

Conference Paper↗

USGS2019

Evaluation of multiple laboratory performance and variability in analysis of recreational freshwaters by a rapid Escherichia coli qPCR method (Draft Method C)

There is interest in the application of rapid quantitative polymerase chain reaction (qPCR) methods for recreational freshwater quality monitoring of the fecal indicator bacteria Escherichia coli ( E. coli ). In this study we determined the performance of 21 laboratories in meeting proposed, standardized data quality acceptance (QA) criteria and the variability of target gene copy estimates from these laboratories in analyses of 18 shared surface water samples by a draft qPCR method developed by the U.S. Environmental Protection Agency (EPA) for E. coli . The participating laboratories ranged from academic and government laboratories with more extensive qPCR experience to “new” water quality and public health laboratories with relatively little previous experience in most cases. Failures to meet QA criteria for the method were observed in 24% of the total 376 test sample analyses. Of these failures, 39% came from two of the “new” laboratories. Likely factors contributing to QA failures included deviations in recommended procedures for the storage and preparation of reference and control materials. A master standard curve calibration model was also found to give lower overall variability in log 10 target gene copy estimates than the delta-delta Ct (ΔΔCt) calibration model used in previous EPA qPCR methods. However, differences between the mean estimates from the two models were not significant and variability between laboratories was the greatest contributor to overall method variability in either case. Study findings demonstrate the technical feasibility of multiple laboratories implementing this or other qPCR water quality monitoring methods with similar data quality acceptance criteria but suggest that additional practice and/or assistance may be valuable, even for some more generally experienced qPCR laboratories. Special attention should be placed on providing and following explicit guidance on the preparation, storage and handling of reference and control materials.

Water Research↗

USGS2018

Stream mercury export in response to contemporary timber harvesting methods (Pacific Coastal Mountains, Oregon, USA)

Land-use activities can alter hydrological and biogeochemical processes that can affect the fate, transformation, and transport of mercury (Hg). Previous studies in boreal forests have shown that forestry operations can have profound, but variable effects on Hg export and methylmercury (MeHg) formation. The Pacific Northwest is an important timber producing region that receives large atmospheric Hg loads, but the impact of forest harvesting on Hg mobilization has not been directly studied and was the focus of our investigation. Stream discharge was measured continuously and Hg and MeHg concentrations measured monthly for 1.5 years following logging in three paired harvested and un-harvested catchments. There was no significant difference in particulate-bound Hg concentrations or loads in the harvested and unharvested catchments which may have resulted from the best management practices aimed at minimizing erosion. However, the harvested catchments had significantly higher discharge (32%), filtered Hg concentrations (28%), filtered Hg loads (80%), and dissolved organic carbon (DOC) loads (40%) compared to forested catchments. MeHg concentrations were low (mostly <0.05 ng L-1) in both harvested, un-harvested and downstream samples due to well-drained/unsaturated soil conditions and steep slopes with high energy eroding stream channels that were not conducive to the development of anoxic conditions. These results have important implications for the role forestry operations have in affecting catchment retention and export of Hg pollution.

Oregon↗

USGS1995

Use and occurrence of pesticides in the Apalachicola-Chattahoochee-Flint River basin, Georgia, Alabama, and Florida, 1960-91

The Apalachicola-Chattahoochee-Flint (ACF) River basin was one of the first 20 study units selected in 1991 by the U.S. Geological Survey for its National Water-Quality Assessment (NAWQA) program. Because pesticide contamination of surface water and ground water is a concern nationwide, a major emphasis of the NAWQA program is to examine the occurrence and distribution of pesticides in the water resources of these study unit basins. An understanding of the types and distribution of land uses; pesticide properties, pest-control practices, and pesticide use; and an evaluation of the occurrence and distribution of pesticides in the water resources of the ACF are necessary to meet this objective of the NAWQA program. This report describes land use and pesticide use at a county level, and the occurrence and distribution of pesticides in the water resources of the ACF River basin on the basis of previously-collected data. About 33 percent of the ACF River basin is used for agriculture, 16 percent is used for silviculture, and about 5 percent of the basin is in urban and suburban settings; primarily the Columbus, Albany, and Atlanta Metropolitan areas. The remainder is in wetlands and non-silvicultural forest. A broad range of synthetic-organic herbicides, insecticides, and fungicides are applied to land in agricultural, silvicultural, urban, and suburban areas. The period of intensive pesticide applications extends from March to October. Pesticide data available for the period from 1971 through 1989 in the U.S. Geological Survey National Water Information System (NWIS) and for the period from 1960 through 1991 in the U.S. Environmental Protection Agency Storage and Retrieval System (STORET) were analyzed to describe the occurrence and distribution of pesticides in water resources of the ACF River basin. Collectively, the NWIS and STORET databases contain about 19,600 individual analyses for pesticide concentration in the ACF River basin. Pesticide concentrations were at or above a minimum reporting level in about five percent of all analyses. Most of the pesticide analyses and most of the analyses having concentrations above minimum reporting levels in these databases are for organochlorine insecticides in samples collected five or more years before this study. With few exceptions, most of organochlorine insecticides are now banned from use in the United States. Concentrations of currently (1991) used pesticides were at or above a minimum reporting level in about 0.3 percent of the analyses. The geographic patterns in the occurrence and distribution of pesticides in the ACF River basin (as defined by data collected during 1960-91) are, as expected, somewhat defined by land-use patterns. DDT (together with DDD and DDE) were detected in wide distribution in the sediments and aquatic biota of primarily mainstem and reservoir sites in the Chattahoochee, Flint, and Apalachicola drainages. DDT was used through 1973 as an insecticide on cotton, fruits, and vegetables; and for mosquito control, so its widespread occurrence in both urban and agricultural settings is consistent with its use. Chlordane, heptachlor, dieldrin, and related compounds were agriculturally used through 1974, but predominantly as termiticides through the late 1980’s. Compounds in these groups have been found in the sediments and aquatic biota of tributary streams draining the Atlanta Metropolitan area and of mainstem reaches and reservoirs of the Chattahoochee River downstream from the Atlanta and Columbus, Ga., Metropolitan areas. The phenoxy-acid herbicides are widely used in residential, commercial/industrial, agricultural, and silvicultural areas of the ACF River basin. Detectable concentrations of 2,4-D were found in most of the surface-waters sampled in the Atlanta Metropolitan area. It is unfortunate that only limited inference can be drawn on temporal patterns. Many of the Federal and State agency pesticide-monitoring programs have been targeted to known sources and areas of contamination, an approach consistent with regulatory requirements focused on human health; and either were synoptic in nature or were conducted during a limited period of time. Thus, the composite temporal picture represented by these sampling efforts is inherently patchy.

Alabama, Florida, Georgia↗

USGS2019

Improved enrichment factor calculations through principal component analysis: Examples from soils near breccia pipe uranium mines, Arizona, USA

The enrichment factor (EF) is a widely used metric for determining how much the presence of an element in a sampling media has increased relative to average natural abundance because of human activity. Calculation of an EF requires the selection of both a background composition and a reference element, choices that can strongly influence the result of the calculation. Here, it is shown how carefully applied, classical principal component analysis (PCA) examined via biplots can guide the selections of background compositions and reference elements. Elemental data were treated using the centered log ratio (CLR) transformation, and multiple subsets of major and trace elements were examined to gain different perspectives. The methodology was applied to a dataset of elemental soil concentrations from around breccia pipe uranium mines in Arizona, U.S.A., with most samples collected via incremental sampling methodology. Storage of ore at the surface creates the potential for wind dispersal of ore-derived material. Uranium was found to be the best individual tracer of dispersal of ore-derived material to nearby soils, with EF values up to 75. Sulfur, As, Mo, and Cu were also enriched but to lesser degrees. The results demonstrate several practical benefits of a PCA in these situations: (1) the ability to identify one or more elements best suited to distinguish a specific source of enrichment from background composition; (2) understanding how background compositions vary within and between sites; (3) identification of samples containing enriched or anthropogenic materials based upon their integrated, multi-element composition. Calculating the most representative EF values is useful for numerical assessment of enrichment, whether anthropogenic or natural. As shown here, however, the PCA and biplot method provide a visual approach that integrates information from all elements for a given subset of data in a manner that yields geochemical insights beyond the power of the EF.

Arizona↗

USGS2023

Understanding the spatiotemporal distribution of snow refugia in the rain-snow transition zone of north-central Idaho

Knowledge of snow cover distribution and disappearance dates over a wide range of scales is imperative for understanding hydrological dynamics and for habitat management of wildlife species that rely on snow cover. Identification of snow refugia, or places with relatively late snow disappearance dates (SDDs) compared to surrounding areas, is especially important as climate change alters snow cover timing and duration. The purpose of this study was to increase understanding of snow refugia in complex terrain spanning the rain-snow transition zone at fine spatial and temporal scales. To accomplish this objective, we used remote cameras to provide relatively high temporal and spatial resolution measurements on snowpack conditions. We built linear models to relate SDDs at the monitoring sites to topoclimatic and canopy cover metrics. One model to quantify SDDs included elevation, aspect, and an interaction between canopy cover and cold-air pooling potential. High-elevation, north-facing sites in cold-air pools (CAPs) had the latest SDDs, but isolated lower-elevation points also exhibited relatively late potential SDDs. Importantly, canopy cover had a much stronger effect on SDDs in CAPs than in non-CAPs, indicating that best practices in forest management for snow refugia could vary across microtopography. A second model that included in situ hydroclimate observations (December – February (DJF) temperature and March 1 snow depth) indicated that March 1 snow depth had little impact on SDD at the coldest winter temperatures, and that DJF temperatures had a stronger effect on SDD at lower snow depths, implying that the relative importance of snowfall and temperature could vary across hydroclimatic contexts in their impact on snow refugia. This new understanding of factors influencing snow refugia can guide forest management actions to increase snow retention and inform management of snow-dependent wildlife species in complex terrain.

Environmental Research Letters↗

USGS2024

Accuracy, accessibility, and institutional capacity shape the utility of habitat models for managing and conserving rare plants on western public lands

Public lands are often managed for multiple uses ranging from energy development to rare plant conservation. Habitat models can help land managers assess and mitigate potential effects of projects on rare plants, but it is unclear how models are currently being used. Our goal was to better understand how staff in the Bureau of Land Management currently use habitat models to inform their decisions, and perceived challenges and benefits associated with that use. We first examined litigation documents to determine whether the agency has been challenged on its use of data for rare plants and found no relevant legal challenges. Second, we analyzed model use in National Environmental Policy Act (NEPA) documents and found no clear citations of habitat models. Finally, we conducted interviews with agency staff who analyze potential effects of proposed actions on rare plants in NEPA documents. The primary challenges interviewees faced in using models related to data organization and access, model quality and accuracy, and institutional capacity. Interviewees believed models could be used more to inform decisions and actions to conserve rare plants and rare plant habitat on public lands and recommended improving staff access to models, creating models for additional species, and addressing staffing limitations.

Arizona, California, Colorado, New Mexico, Utah, W↗

USGS1995

Indicators of the sources and distribution of nitrate in water from shallow domestic wells in agricultural areas of the New Jersey Coastal Plain

Previously collected and new water-quality data from shallow wells (screened interval less than 30 meters below the land surface) in predominantly agricultural areas of the New Jersey Coastal Plain were used to determine the relation of nitrate concentrations in shallow ground water to various hydrogeologic and land-use factors in the study area. Information on land use, well construction, hydrogeology, and water quality were used to predict the conditions under which concentrations of nitrate as nitrogen in water from domestic wells in predominantly agricultural areas are most likely to be equal to or larger than the U.S. Environmental Protection Agency maximum contaminant level (MCL) of 10 milligrams per liter. Results of the analyses of water-quality samples collected during 1980-89 from 230 shallow wells in the outcrop areas of the Kirkwood-Cohansey and Potomac-Raritan-Magothy aquifer systems were used to evaluate the regional effects of land use on shallow-ground-water quality. Results of statistical analysis indicate that concentrations of nitrate in shallow ground water are significantly different (p= 0.001) in agricultural areas than in undeveloped areas in both aquifer systems. Concentrations of nitrate nitrogen exceeded the MCL in water from more than 33 percent of the 60 shallow wells in agricultural areas. Concentrations of hitrate in water from shallow wells in agricultural areas increased as the percentage of agricultural land within an 800-meter-radius buffer zone of the wellhead increased (r= 0.81). Concentrations ofhitrate in water from domestic wells in agricultural areas were similar (p= 0.23) to those concentrations in water from irrigation wells. These results indicate that most of the nitrate in water from domestic wells in agricultural areas results from agricultural practices rather than other sources, such as septic systems. Water-quality samples collected from 12 shallow domestic wells in agricultural areas screened in the outcrop areas of the Kirkwood-Cohansey and Potomac-Raritan-Magothy aquifer systems were used to evaluate the local effects of hydrogeologic conditions and land-use activities on shallow-ground-water quality. Concentrations of water-quality constituents in these wells were similar among four sampling events over a l-year span. The concentration of hitrate in water from 6 of the 12 wells exceeded the MCL. Concentrations of nitrate greater than the MCL are associated with: values of specific conductance greater than 200 microsiemens per centimeter at 25 degrees Celsius, a screened interval whose top is less than 20 meters below land surface, concentrations of dissolved oxygen greater than 6 milligrams per liter, presence of pesticides in the ground water, a distance of less than 250 meters between the wellhead and the surfacewater divide, and presence of livestock near the wellhead. Ratios of stable isotopes of nitrogen in the water samples indicate that the source of hitrate in the ground water was predominantly chemical fertilizers rather than livestock wastes or effluent from septic systems.

Water-Resources Investigations Report↗

USGS2000

Aquatic ecosystem protection and restoration: Advances in methods for assessment and evaluation

Many methods and criteria are available to assess aquatic ecosystems, and this review focuses on a set that demonstrates advancements from community analyses to methods spanning large spatial and temporal scales. Basic methods have been extended by incorporating taxa sensitivity to different forms of stress, adding measures linked to system function, synthesizing multiple faunal groups, integrating biological and physical attributes, spanning large spatial scales, and enabling simulations through time. These tools can be customized to meet the needs of a particular assessment and ecosystem. Two case studies are presented to show how new methods were applied at the ecosystem scale for achieving practical management goals. One case used an assessment of biotic structure to demonstrate how enhanced river flows can improve habitat conditions and restore a diverse fish fauna reflective of a healthy riverine ecosystem. In the second case, multitaxonomic integrity indicators were successful in distinguishing lake ecosystems that were disturbed, healthy, and in the process of restoration. Most methods strive to address the concept of biological integrity and assessment effectiveness often can be impeded by the lack of more specific ecosystem management objectives. Scientific and policy explorations are needed to define new ways for designating a healthy system so as to allow specification of precise quality criteria that will promote further development of ecosystem analysis tools.

Environmental Science and Policy↗

USGS1996

Small watershed studies: Analytical approaches for understanding ecosystem response to environmental change

Biogeochemical studies in small watersheds provide an analytical approach to understand how ecosystems respond to natural climatic variations and human-induced environmental change. Small watersheds, usually less than 5 km2, are small enough to permit characterization and understanding of ecosystem processes within relatively simple, homogeneous biological and physical settings; yet they are large enough to incorporate more complex processes and element cycles than can be studied at plot scales. Watersheds comprise discrete hydrochemical environments allowing quantification of hydrologic, element, and energy budgets. Element budgets, or mass balances, can be quantified as the difference between the mass of a solute that enters a watershed in wet and dry deposition and leaves a watershed in streamflow. Element budgets are primary tools used to investigate biogeochemical processes. Monitoring various aspects of element budgets to assess ecosystem health and stability is analogous to measuring the pulse or blood chemistry of a patient. Monitoring streamwater chemistry, basic climate, soil, and biotic variables provide a means to integrate complex biogeochemical processes and evaluate trends in water quality. Small watershed studies provide a scientific basis to develop predictive models of watershed function. Major emphases of small watershed studies include investigation of hydrologic and chemical responses to natural climate variation, anthropogenic stressors, and alternate forest-management practices. The nature and significance of biogeochemical research in small watersheds is reviewed by Moldan and Cerny (1994). The U.S. Geological Survey, U.S. Department of Agriculture Forest Service, and other federal agencies support several long-term small watershed studies to provide insight into a variety of ecosystem processes. Long-term records are essential to distinguish trends resulting from natural climatic variations or other stressors. The following sites, with noted periods of records, are examples of intensively studied forested watersheds in eastern USA supported by federal agencies: ■ Coweeta Hydrologic Laboratory, North Carolina, (1939-present), Swank and Crossley (1988). ■ Hubbard Brook Experimental Forest, New Hampshire, (1956-present), Bormann and Likens (1979). ■ Sleepers River Research Watershed, Vermont, (1958-present), Shanley et al. (1995). ■ Walker Branch Watershed, Tennessee, (1967-present), Johnson and Van Hook (1989). ■ Catoctin Mountains Research Site, Maryland, (1982-present), Rice and Bricker (1995). ■ Catskill Stream Network, New York, (1983- present), Murdoch and Stoddard (1992). ■ Panola Mountain Research Watershed, Georgia, (1985-present), Huntington et al. (1993). Small watershed studies also provide essential baseline information for understanding variations in water quality and element cycling in "pristine" ecosystems that can be used as benchmarks to evaluate anthropogenic impacts and alternate watershed management practices. This paper provides examples of how analytical tools developed through watershed research provide insight into ecosystem processes and can contribute to the management of watershed resources.

Conference Paper↗

USGS2024

Expanded conceptual risk framework for uranium mining in Grand Canyon watershed—Inclusion of the Havasupai Tribe perspective

In 2012, the Secretary of the U.S. Department of the Interior placed a 20-year limit on mineral extraction on Federal lands in the Grand Canyon watershed to permit further study of the environmental effects of uranium mining. Tribal concerns were also noted by the U.S. Department of the Interior and included in the rationale for the decision stating Tribal resource impacts could not be mitigated and cultural degradation may result should mining occur within sacred and traditional places of Tribal peoples. The U.S. Geological Survey previously developed a conceptual framework for a uranium mine in the region that defined contaminant sources and physical, chemical, and biological processes that affect contaminant transport to ecological receptors. However, published risk models have largely ignored exposure pathways relevant to Tribal communities in terms of traditional uses and existential values of the resources included. This report presents an updated conceptual risk framework for uranium mining that includes indigenous knowledge components informed by the Havasupai Tribe perspective. The expansion of the framework relied on connecting to the foundations of the Havasupai ceremonial wheel—food, environment, belief system, and ceremony. The framework is applied to uranium development near Red Butte, an important gathering place for multiple federally recognized Tribes including the Havasupai, Hopi, Navajo, and Zuni. Plants and animals important to the Havasupai for subsistence, ceremonial, and medicinal practices and how mining affects these practices are described. The final framework is presented in English and Havasupai to aid Tribal members in understanding how the framework relates to their community and to help preserve the language and historical cultural practices for future generations. New or expanded exposure pathways include inhalation, ingestion, and absorption from traditional food and medicines as well as ceremonial practices. The updated framework has allowed the U.S. Geological Survey to take first steps in understanding resources important to the Havasupai and to build relationships to improve co-production in our research. Ideally, the framework and other research can be used, along with indigenous knowledge, in Federal research and decision making for mining in the Grand Canyon region.

Open-File Report↗

USGS2023

Urban stream restorations increase floodplain soil carbon and nutrient retention along a chronosequence

Stream restoration is a common management practice to meet regulatory or voluntary efforts to improve water quality via nutrient and carbon (C) retention, including in the Chesapeake Bay watershed. However, most restoration projects have few quantifiable measures of project success, no standard metrics, and rarely collect pre-restoration data. Storage of nutrients, such as phosphorus (P) and nitrogen (N), in floodplain soils of restored streams can act as an easily quantifiable indicator of restoration success, particularly when the project goals include improved water quality. To determine how floodplains of restored streams change in their P and C storage as time since restoration increases, floodplain surficial soil samples (10 cm depth) were collected from 18 streams in the urbanized Piedmont region of northern Virginia, representing a chronosequence of time (1–10+ yrs.) since restoration as well as unrestored streams with high impervious surface cover (ISC) and unrestored streams with low ISC. The samples were analyzed for total carbon (TC), total nitrogen (TN) and total phosphorus (TP) storage, whereas C turnover rate and equilibrium phosphorus concentration (EPC 0 ) were measured as metrics of C and P loss. These metrics were compared to time since restoration and potential environmental drivers, including soil moisture, pH, median particle size (D50), organic matter content (OM), and bioavailable P, iron (Fe), and aluminum (Al). These stream restorations demonstrated increasing nutrient storage for TC, TN, and TP along the chronosequence to values greater than both unrestored or reference streams, as well as decreasing C turnover and no significant changes in EPC 0 . Soil wetness and OM, key drivers in nutrient retention, also increased as restoration projects aged increasing C, N, and P storage. Overall, stream restoration did improve soil C, N, and P retention in floodplains as compared to unrestored sites and exceeded those of low ISC ‘reference’ sites.

Virginia↗

USGS1999

Historical trends in salinity and substrate in central and northern Florida Bay: A Paleoecological Reconstruction using modern analogue data

Understanding the natural spatial and temporal variability that exists within an ecosystem is a critical component of efforts to restore systems to their natural state. Analysis of benthic foraminifers and molluscs from modern monitoring sites within Florida Bay allows us to determine what environmental parameters control spatial and temporal variability of their assemblages. Faunal assemblages associated with specific environmental parameters, including salinity and substrate, serve as proxies for an interpretation of paleoecologic data. The faunal record preserved in two shallow (<2 m) cores in central Florida Bay (Russell Bank and Bob Allen Bank) provides a record of historical trends in environmental parameters for those sites. Analysis of these two cores has revealed two distinct patterns of salinity change at these sites: 1) a long-term trend of slightly increasing average salinity; and 2) a relatively rapid change to salinity fluctuations of greater frequency and amplitude, beginning around the turn of the century and becoming most pronounced after 1940. The degree of variability in substrate types at each locality limits interpretations of substrate trends to specific sites. A common sequence of change is present in the Russell Bank and Bob Allen Bank cores: from mixed grass and bare-sediment indicators at the bottom of the cores, to bare-sediment dwellers in the center, to a dominance of vegetative-cover indicators at the top of the cores. Changes in interpreted salinity patterns around the turn of the century are consistent with the timing of the construction of the Flagler Railroad from 1905 to 1912, and the Tamiami Trail and the canal and levee systems between 1915 and 1928. Beginning around 1940, the changes in the frequency and amplitude of salinity fluctuations may be related to changes in water management practices, meteorologic events (frequent hurricanes coupled with severe droughts in 1943 and 1944), or a combination of factors. The correspondence of these changes in Florida Bay with changes in the terrestrial Everglades suggests factors affecting the entire ecosystem are responsible for the salinity and substrate patterns seen in Florida Bay.

Florida↗

USGS2016

Facilitating the inclusion of nonmarket values in Bureau of Land Management planning and project assessments—Final report

Executive Summary This report summarizes the results of a series of field-based case studies conducted by the U.S. Geological Survey (USGS) to (1) evaluate the use of nonmarket values in Bureau of Land Management (BLM) planning and project assessments, (2) update existing technical resources for measuring those values, and (3) provide guidance to field staff on the use of nonmarket values. Four BLM pilot sites participated in this effort: Canyons of the Ancients National Monument in Colorado, Red Cliffs and Beaver Dam Wash National Conservation Areas in Utah, BLM’s Taos Field Office in New Mexico, and BLM's Tuscarora Field Office in Nevada. The focus of the case studies was on practical applications of nonmarket valuation. USGS worked directly with BLM field staff at the pilot sites to demonstrate the process of considering nonmarket values in BLM decisionmaking and document the questions, challenges, and opportunities that arise when tying economic language to projects. As part of this effort, a Web-based toolkit, available at https://my.usgs.gov/benefit-transfer/ , was updated and expanded to help facilitate benefit transfers (that is, the use of existing economic data to quantify nonmarket values) and qualitative discussions of nonmarket values. A total of 53 new or overlooked nonmarket valuation studies comprising 494 nonmarket value estimates for various recreational activities and the preservation of threatened, endangered, and rare species were added to existing databases within this Benefit Transfer Toolkit. In addition, four meta-regression functions focused on hunting, wildlife viewing, fishing, and trail use recreation were developed and added to the Benefit Transfer Toolkit. Results of this effort demonstrate that there are two main roles for nonmarket valuation in BLM planning. The first is to improve the decisionmaking process by contributing to a more comprehensive comparison of economic benefits and cost when evaluating resource tradeoffs for National Environmental Policy Act analyses. The second is to use economic language and information on economic values, either qualitative or quantitative, to improve the ability to communicate the economic significance of the resources provided by BLM-managed lands. Findings also indicate that the use of existing economic data to quantify nonmarket values (that is, benefit transfer) poses unique challenges because of the scarcity of both resource data and existing valuation studies focused on resources and sites managed by BLM. This highlights the need for improvements in the collection of resource data at BLM sites, especially visitor use data, as well as an opportunity for BLM’s Socioeconomics Program to strategically identify priority areas, in terms of both resources and geographic locations, where primary valuation studies could be conducted and the results used for future benefit transfers. Finally, whereas qualitative discussions of nonmarket values do not facilitate the comparison of monetized values, they can provide a manageable next step forward in providing more comprehensive information on nonmarket values for BLM plans and project assessments.

Open-File Report↗

USGS1994

Relation of stream quality to streamflow, and estimated loads of selected water-quality constituents in the James and Rappahannock rivers near the fall line of Virginia, July 1988 through June 1990

This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Virginia Department of Environmental Quality-- Division of Intergovernmental Coordination to monitor and estimate loads of selected nutrients and suspended solids discharged to Chesapeake Bay from two major tributaries in Virginia. From July 1988 through June 1990, monitoring consisted of collecting depth-integrated, cross-sectional samples from the James and Rappahannock Rivers during storm- flow conditions and at scheduled intervals. Water- quality constituents that were monitored included total suspended solids (residue, total at 105 degrees Celsius), dissolved nitrite plus nitrate, dissolved ammonia, total Kjeldahl nitrogen (ammonia plus organic), total nitrogen, total phosphorus, dissolved orthopohosphorus, total organic carbon, and dissolved silica. Daily mean load estimates of each constituent were computed by month, using a seven-parameter log-linear-regression model that uses variables of time, discharge, and seasonality. Water-quality data and constituent- load estimates are included in the report in tabular and graphic form. The data and load estimates provided in this report will be used to calibrate the computer modeling efforts of the Chesapeake Bay region, evaluate the water quality of the Bay and the major effects on the water quality, and assess the results of best-management practices in Virginia.

Water-Resources Investigations Report↗

USGS2009

Options for national parks and reserves for adapting to climate change

Past and present climate has shaped the valued ecosystems currently protected in parks and reserves, but future climate change will redefine these conditions. Continued conservation as climate changes will require thinking differently about resource management than we have in the past; we present some logical steps and tools for doing so. Three critical tenets underpin future management plans and activities: (1) climate patterns of the past will not be the climate patterns of the future; (2) climate defines the environment and influences future trajectories of the distributions of species and their habitats; (3) specific management actions may help increase the resilience of some natural resources, but fundamental changes in species and their environment may be inevitable. Science-based management will be necessary because past experience may not serve as a guide for novel future conditions. Identifying resources and processes at risk, defining thresholds and reference conditions, and establishing monitoring and assessment programs are among the types of scientific practices needed to support a broadened portfolio of management activities. In addition to the control and hedging management strategies commonly in use today, we recommend adaptive management wherever possible. Adaptive management increases our ability to address the multiple scales at which species and processes function, and increases the speed of knowledge transfer among scientists and managers. Scenario planning provides a broad forward-thinking framework from which the most appropriate management tools can be chosen. The scope of climate change effects will require a shared vision among regional partners. Preparing for and adapting to climate change is as much a cultural and intellectual challenge as an ecological challenge.

Environmental Management↗

USGS2021

Coastal wetland shoreline change monitoring: A comparison of shorelines from high-resolution WorldView satellite imagery, aerial imagery, and field surveys

Shoreline change analysis is an important environmental monitoring tool for evaluating coastal exposure to erosion hazards, particularly for vulnerable habitats such as coastal wetlands where habitat loss is problematic world-wide. The increasing availability of high-resolution satellite imagery and emerging developments in analysis techniques support the implementation of these data into shoreline monitoring. Geospatial shoreline data created from a semi-automated methodology using WorldView (WV) satellite data between 2013 and 2020 were compared to contemporaneous field-surveyed Global Position System (GPS) data. WV-derived shorelines were found to have a mean difference of 2 ± 0.08 m of GPS data, but accuracy decreased at high-wave energy shorelines that were unvegetated, bordered by sandy beach or semi-submergent sand bars. Shoreline change rates calculated from WV imagery were comparable to those calculated from GPS surveys and geospatial data derived from aerial remote sensing but tended to overestimate shoreline erosion at highly erosive locations (greater than 2 m yr −1 ). High-resolution satellite imagery can increase the spatial scale-range of shoreline change monitoring, provide rapid response to estimate impacts of coastal erosion, and reduce cost of labor-intensive practices.

Remote Sensing↗