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At least 1,801 records · Page 100Linked to original sources
USGS2017

Streamflow alteration at selected sites in Kansas

An understanding of streamflow alteration in response to various disturbances is necessary for the effective management of stream habitat for a variety of species in Kansas. Streamflow alteration can have negative ecological effects. Using a modeling approach, streamflow alteration was assessed for 129 selected U.S. Geological Survey streamgages in the State for which requisite streamflow and basin-characteristic information was available. The assessment involved a comparison of the observed condition from 1980 to 2015 with the predicted expected (least-disturbed) condition for 29 streamflow metrics. The metrics represent various characteristics of streamflow including average flow (annual, monthly) and low and high flow (frequency, duration, magnitude). Streamflow alteration in Kansas was indicated locally, regionally, and statewide. Given the absence of a pronounced trend in annual precipitation in Kansas, a precipitation-related explanation for streamflow alteration was not supported. Thus, the likely explanation for streamflow alteration was human activity. Locally, a flashier flow regime (typified by shorter lag times and more frequent and higher peak discharges) was indicated for three streamgages with urbanized basins that had higher percentages of impervious surfaces than other basins in the State. The combination of localized reservoir effects and regional groundwater pumping from the High Plains aquifer likely was responsible, in part, for diminished conditions indicated for multiple streamflow metrics in western and central Kansas. Statewide, the implementation of agricultural land-management practices to reduce runoff may have been responsible, in part, for a diminished duration and magnitude of high flows. In central and eastern Kansas, implemented agricultural land-management practices may have been partly responsible for an inflated magnitude of low flows at several sites.

Kansas↗
USGS1997

Occurrence of nitrate, pesticides, and volatile organic compounds in the Kirkwood-Cohansey aquifer system, southern New Jersey

Water samples were collected from a network of 72 shallow monitoring wells to assess the chemical quality of recently recharged ground water in the surficial Kirkwood- Cohansey aquifer system of southern New Jersey. The wells are randomly distributed among agricultural, urban, and undeveloped areas to provide data representative of chemical conditions of ground water underlying each of these land-use settings. Samples were analyzed for nutrients, pesticides, and volatile organic compounds (VOC's). Concentrations of nitrate were highest in agricultural areas, where the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) of 10 mg/L (milligrams per liter) as nitrogen was exceeded in 60 percent of the samples. Concentrations of nitrate were intermediate in urban areas, where the 10-mg/L concentration was exceeded in only 1 of 44 samples. All concentrations in samples from undeveloped areas were less than 1.0 mg/L. Pesticides and VOC's were frequently detected; however, concentrations were low and rarely exceeded established or proposed USEPA or N.J. Department of Environmental Protection (NJDEP) drinking-water regulations. With the exception of the agricultural pesticide dinoseb, established regulations are at least 2.9 times the maximum concentration for pesticides and at least 5 times the maximum concentration for VOC's reported in the samples from the 72-well network. Investigations by the U.S. Geological Survey (USGS) are ongoing in southern New Jersey to evaluate the (1) presence and concentration of pesticide-degradation byproducts in shallow ground water; (2) presence and movement of nitrate, pesticides, and VOC's in the atmosphere, streams, unsaturated zone, and aquifers; (3) transport and fate of these compounds as they migrate deeper into the aquifer system; and (4) implications of these findings for the integrity of the regional water supply.

New Jersey↗
USGS2005

Coastal vulnerability assessment of War in the Pacific National Historical Park to sea-level rise

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within War in the Pacific National Historical Park (NHP) on the island of Guam. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined, and an index value calculated for 200-meter grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. War in the Pacific NHP consists of sand beaches and rock headlands. The areas within War in the Pacific NHP that are likely to be most vulnerable to sea-level rise are areas of unconsolidated sediment where coastal slope is lowest and wave energy is high.

Open-File Report↗
USGS2006

Coastal vulnerability assessment of Kaloko-Honokohau National Historical Park to sea-level rise

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Kaloko-Honokohau National Historical Park in Hawaii. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined, and an index value calculated for 500-meter grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Kaloko-Honokohau National Historical Park consists of carbonate sand beaches, coral rubble, rocky shoreline, and mangrove wetland areas. The areas within Kaloko-Honokohau National Historical Park that are likely to be most vulnerable to sea-level rise based on this analysis are areas of unconsolidated sediment and highest wave energy.

Hawaii↗
USGS2006

Total Petroleum Systems of the North Carpathian Province of Poland, Ukraine, Czech Republic, and Austria

Three total petroleum systems were identified in the North Carpathian Province (4047) that includes parts of Poland, Ukraine, Austria, and the Czech Republic. They are the Isotopically Light Gas Total Petroleum System, the Mesozoic-Paleogene Composite Total Petroleum System, and the Paleozoic Composite Total Petroleum System. The Foreland Basin Assessment Unit of the Isotopically Light Gas Total Petroleum System is wholly contained within the shallow sedimentary rocks of Neogene molasse in the Carpathian foredeep. The biogenic gas is generated locally as the result of bacterial activity on dispersed organic matter. Migration is also believed to be local, and gas is believed to be trapped in shallow stratigraphic traps. The Mesozoic-Paleogene Composite Total Petroleum System, which includes the Deformed Belt Assessment Unit, is structurally complex, and source rocks, reservoirs, and seals are juxtaposed in such a way that a single stratigraphic section is insufficient to describe the geology. The Menilite Shale, an organic-rich rock widespread throughout the Carpathian region, is the main hydrocarbon source rock. Other Jurassic to Cretaceous formations also contribute to oil and gas in the overthrust zone in Poland and Ukraine but in smaller amounts, because those formations are more localized than the Menilite Shale. The Paleozoic Composite Total Petroleum System is defined on the basis of the suspected source rock for two oil or gas fields in western Poland. The Paleozoic Reservoirs Assessment Unit encompasses Devonian organic-rich shale believed to be a source of deep gas within the total petroleum system. East of this field is a Paleozoic oil accumulation whose source is uncertain; however, it possesses geochemical similarities to oil generated by Upper Carboniferous coals. The undiscovered resources in the North Carpathian Province are, at the mean, 4.61 trillion cubic feet of gas and 359 million barrels of oil. Many favorable parts of the province have been extensively explored for oil and gas. The lateral and vertical variability of the structure, the distribution and complex geologic nature of source rocks, and the depths of potential exploration targets, as well as the high degree of exploration, all indicate that future discoveries in this province are likely to be numerous but in small fields.

Bulletin↗
USGS2017

Everglades Depth Estimation Network (EDEN)—A decade of serving hydrologic information to scientists and resource managers

Introduction The Everglades Depth Estimation Network (EDEN) provides scientists and resource managers with regional maps of daily water levels and depths in the freshwater part of the Greater Everglades landscape. The EDEN domain includes all or parts of five Water Conservation Areas, Big Cypress National Preserve, Pennsuco Wetlands, and Everglades National Park. Daily water-level maps are interpolated from water-level data at monitoring gages, and depth is estimated by using a digital elevation model of the land surface. Online datasets provide time series of daily water levels at gages and rainfall and evapotranspiration data ( https://sofia.usgs.gov/eden/ ). These datasets are used by scientists and resource managers to guide large-scale field operations, describe hydrologic changes, and support biological and ecological assessments that measure ecosystem response to the implementation of the Comprehensive Everglades Restoration Plan. EDEN water-level data have been used in a variety of biological and ecological studies including (1) the health of American alligators as a function of water depth, (2) the variability of post-fire landscape dynamics in relation to water depth, (3) the habitat quality for wading birds with dynamic habitat selection, and (4) an evaluation of the habitat of the Cape Sable seaside sparrow.

Florida↗
USGS2015

Status and trends of land change in the Midwest–South Central United States—1973 to 2000

U.S. Geological Survey (USGS) Professional Paper 1794–C is the third in a four-volume series on the status and trends of the Nation’s land use and land cover, providing an assessment of the rates and causes of land-use and land-cover change in the Midwest–South Central United States between 1973 and 2000. Volumes A, B, and D provide similar analyses for the Western United States, the Great Plains of the United States, and the Eastern United States, respectively. The assessments of land-use and land-cover trends are conducted on an ecoregion-by-ecoregion basis, and each ecoregion assessment is guided by a nationally consistent study design that includes mapping, statistical methods, field studies, and analysis. Individual assessments provide a picture of the characteristics of land change occurring in a given ecoregion; in combination, they provide a framework for understanding the complex national mosaic of change and also the causes and consequences of change. Thus, each volume in this series provides a regional assessment of how (and how fast) land use and land cover are changing, and why. The four volumes together form the first comprehensive picture of land change across the Nation. Geographic understanding of land-use and land-cover change is directly relevant to a wide variety of stakeholders, including land and resource managers, policymakers, and scientists. The chapters in this volume present brief summaries of the patterns and rates of land change observed in each ecoregion in the Midwest–South Central United States, together with field photographs, statistics, and comparisons with other assessments. In addition, a synthesis chapter summarizes the scope of land change observed across the entire Midwest–South Central United States. The studies provide a way of integrating information across the landscape, and they form a critical component in the efforts to understand how land use and land cover affect important issues such as the provision of ecological goods and services and also the determination of risks to, and vulnerabilities of, human communities. Results from this project also are published in peer-reviewed journals, and they are further used to produce maps of change and other tools for land management, as well as to provide inputs for carbon-cycle modeling and other climate change research.

Professional Paper↗
USGS2005

Coastal vulnerability assessment of Golden Gate National Recreation Area to sea-level rise

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within the legislative boundary of Golden Gate National Recreation Area (GGNRA) in Northern California. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined, and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. The GGNRA coastlines consists of sand and gravel beaches, rock cliffs, sand dune cliffs, unconsolidated bluffs, and pocket beaches. The areas within GGNRA that are likely to be most vulnerable to sea-level rise are areas of unconsolidated sediment where shoreline erosion rates are high and wave energy is high.

Open-File Report↗
USGS2018

Interior Least Tern sandbar nesting habitat measurements from Landsat Thematic Mapper imagery

Sandbars of large sand-bedded rivers of the central United States serve important ecological functions to many species, including the endangered Interior Least Tern ( Sternula antillarum , ILT). The ILT is a colonial bird that feeds on fish and nests primarily on riverine sandbars during its annual breeding season of around May through July, depending on region. During this time, ILTs require bare sand of sufficient elevation so as not to be inundated between nest initiation and fledging of hatchlings. Partly because of decreases in available sandbar habitat from river channelization and impoundment, ILTs were listed as endangered in 1985. Sandbars used by ILTs in central United States rivers are highly dynamic and undergo substantive changes across a wide range of temporal and spatial scales. River hydrology is the primary driver of sandbar morphodynamics in these systems. Better characterization of sandbar area with time, accounting for varying flow regimes, allows for a better understanding of landscape-scale ecology for sandbar-dependent species such as the ILT. This work uses remote-sensing techniques to quantify sandbar area that may be used by ILTs at the land-scape scale and how it has changed with time. The assessment of landscape-scale trends in sandbar area with time requires datasets with high temporal resolution and long record periods covering large geographic areas. Evaluation of remotely sensed datasets requires consideration of river stage fluctuations. To make this assessment, we developed land-cover classification datasets within active channel masks using all available images from the Landsat Thematic Mapper series of satellites meeting cloud-free (40 percent or less) and ice-free criteria. Landsat imagery was selected because of its long record period, spatial coverage, and regular reimaging cycle, making it well suited to monitor ILT sandbar habitat with time. We also attributed each scene with discharge or stage using a new database integrating U.S. Geological Survey and U.S. Army Corps of Engineers river data with Landsat metadata. This report documents development of these riverine classification datasets with a focus on applicability to the ILT. This framework may be used to continue monitoring the ILT sandbar nesting habitat or to evaluate other aquatic and terrestrial species whose life cycles are related to sandbars and channel complexity.

Data Series↗
USGS2018

Completion summary for borehole TAN-2312 at Test Area North, Idaho National Laboratory, Idaho

In 2017, the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, drilled and constructed borehole TAN-2312 for stratigraphic framework analyses and long-term groundwater monitoring of the eastern Snake River Plain aquifer at the Idaho National Laboratory in southeast Idaho. The location of borehole TAN-2312 was selected because it was downgradient from TAN and believed to be the outer extent of waste plumes originating from the TAN facility. Borehole TAN-2312 initially was cored to collect continuous geologic data, and then re-drilled to complete construction as a monitor well. The final construction for borehole TAN-2312 required 16- and 10-inch (in.) diameter carbon-steel well casing to 37 and 228 feet below land surface (ft BLS), respectively, and 9.9-in. diameter open-hole completion below the casing to 522 ft BLS. Depth to water is measured near 244 ft BLS. Following construction and data collection, a temporary submersible pump and water-level access line were placed near 340 ft BLS to allow for aquifer testing, for collecting periodic water samples, and for measuring water levels. Borehole TAN-2312 was cored continuously, starting at the first basalt contact (about 37 ft BLS) to a depth of 568 ft BLS. Not including surface sediment (0–37 ft), recovery of basalt and sediment core at borehole TAN-2312 was about 93 percent; however, core recovery from 170 to 568 ft BLS was 100 percent. Based on visual inspection of core and geophysical data, basalt examined from 37 to 568 ft BLS consists of about 32 basalt flows that range from approximately 3 to 87 ft in thickness and 4 sediment layers with a combined thickness of approximately 76 ft. About 2 ft of total sediment was described for the saturated zone, observed from 244 to 568 ft BLS, near 296 and 481 ft BLS. Sediment described for the saturated zone were composed of fine-grained sand and silt with a lesser amount of clay. Basalt texture for borehole TAN-2312 generally was described as aphanitic, phaneritic, and porphyritic. Basalt flows varied from highly fractured to dense with high to low vesiculation. Geophysical and borehole video logs were collected after core drilling and after final construction at borehole TAN-2312. Geophysical logs were examined synergistically with available core material to suggest zones where groundwater flow was anticipated. Natural gamma log measurements were used to assess sediment layer thickness and location. Neutron and gamma-gamma source logs were used to identify fractured areas for aquifer testing. Acoustic televiewer logs, fluid logs, and electromagnetic flow meter results were used to identify fractures and assess groundwater movement when compared against neutron measurements. Furthermore, gyroscopic deviation measurements were used to measure horizontal and vertical displacement for borehole TAN-2312. After construction of borehole TAN-2312, a single-well aquifer test was completed September 27, 2017, to provide estimates of transmissivity and hydraulic conductivity. Estimates for transmissivity and hydraulic conductivity were 1.51×102 feet squared per day and 0.23 feet per day, respectively. During the 220-minute aquifer test, well TAN-2312 had about 23 ft of measured drawdown at sustained pumping rate of 27.2 gallons per minute. The transmissivity and hydraulic conductivity estimates for well TAN-2312 were lower than the values determined from previous aquifer tests in other wells near Test Area North. Water samples were analyzed for cations, anions, metals, nutrients, volatile organic compounds, stable isotopes, and radionuclides. Water samples for most of the inorganic constituents showed concentrations near background levels for eastern regional groundwater. Water samples for stable isotopes of oxygen, hydrogen, and sulfur indicated some possible influence of irrigation on the water quality. The volatile organic compound data indicated that this well had some minor influence by wastewater disposal practices at Test Area North.

Idaho↗
USGS2025

Appendix B: Patterns of bull trout Salvelinus confluentus demography, life history, abundance, and trends in the Lewis River

Declines in the distribution and abundance of bull trout ( Salvelinus confluentus ) across much of the historical range in the Pacific Northwest region of Canada and the United States have been well documented (Post and Johnston 2002; Rieman et al. 1997). Recent estimates of population trends appear to vary considerably across regions with large numbers of migratory and resident populations exhibiting substantial declines in adult abundance (Al-Chokhachy et al. 2016; Kovach et al. 2018), whereas others remain stable or potentially increasing (Erhardt and Scarnecchia 2014; Meyer et al. 2014). For example, 61% of the core populations in Alberta, Canada, are considered declining, and 39% are stable or increasing (Alberta Sustainable Resource Development 2012). The variability in population status and trends highlights the importance of population-specific data. Much of our understanding of bull trout life history has stemmed from a few, well-studied populations, and continuing to improve our knowledge of the variability in life-history expressions (e.g., Starcevich et al. 2012) can support directing local and regional conservation efforts (sensu Schindler et al. 2010). Here, we consider the life history, demographic patterns, and assess potential threats for an adfluvial population of bull trout in the upper Lewis River basin in Washington, USA. We synthesized recent monitoring efforts and field studies to refine our understanding of bull trout life-history expressions (i.e., migration patterns), demographics, and genetic status. We further evaluated the potential threats of brook trout ( S. fontinalis ), a species that is not native to the Lewis River, but which was recently documented in bull trout monitoring efforts (Al-Chokhachy et al. 2024). Our specific objectives included evaluating: (1) trends in size structure of subadults and adult bull trout (2014 – 2024); (2) patterns of adult migration and life-history and climate drivers of migration patterns (2011 – 2024); (3) the within-year temporal patterns of bull trout and coho salmon ( Oncorhynchus kisutch ) spawning and superimposition of bull trout redds by spawning coho salmon (2024); (4) temporal trends in abundance for adult and juvenile bull trout from annual monitoring methods (2008 – 2024); and (5) the current (2024) extent of non-native brook trout in wetland habitat adjacent to Yale Lake.

Washington↗
USGS1975

Dissolved solids, hardness, and orthophosphate of surface-water runoff in the Suwannee River Water Management District, Florida

This atlas consists of three maps that show the general distri bution of dissolved solids, hardness, and orthophosphate in the streams and lakes within the Suwannee River Water Management District. The atlas was prepared in cooperation with the Water Management District to provide pertinent water-quality information relating to the objectives of the Florida State Water Resources Act of 1972. Under the provisions of this act, the Water Management District is required to establish a regional water-use plan, issue permits for water-use and water-resources related construction, and authorize the export of water. The data presented on these maps will be useful to those concerned with water management and use, in assessing regional water quality, and in estab lishing a base for comparison with future quality data. The ranges of concentration shown on the maps represent maximum concentrations in surface water during the sampling period, January 1965- September 1970. Concentrations are plotted at the sampling sites and are the major criteria for determining the extent of concentration ranges. In some cases the drainage basin boundaries are used in defining concentration range boundaries because the quantity and quality of surface runoff is characteristic of the environment of the basin and may be entirely different from the runoff of adjacent basins. Within drainage basins, individual streams and local drainage divides define concentration boundaries. Some areas, although adjacent to each other in the same basin, have entirely different concentration ranges. For example, an area containing dissolved-solids concentrations in the 0-25 mg/1 (milligrams per litre) range may be adjacent to an area in which concentrations exceed 100 mg/1, as in the southeast part of Jefferson County. Concentration boundaries in these areas were selected by extending each range about halfway between the two sampling sites, as opposed to grading an intermediate range between them without supporting data. As the data are sparse in many areas, regional concentration patterns are generalized and local variations may be expected to exist.

Florida↗
USGS1976

Dissolved solids, hardness, and orthophosphate of surface-water runoff in the Northwest Florida Water Management District

This atlas consists of three maps that show the general distri bution of dissolved solids, hardness, and orthophosphate in the streams and lakes within the Northwest Florida Water Management District. The atlas was prepared in cooperation with the Water Management District to provide pertinent water-quality information relating to the objectives of the Florida State Water Resources Act of 1972. Under the provisions of this act, the Water Management District is required to establish a regional water-use plan, issue permits for water-use and water-resources related construction, and authorize the export of water. The data presented on these maps will be useful to those concerned with water management and use, in assessing regional water quality, and in estab lishing a base for comparison with future quality data. The ranges of concentration shown on the maps represent maximum concentrations in surface water during the sampling period, January 1965-September 1970. Concentrations are plotted at the sampling sites and are the major criteria for determining the extent of concentration ranges. In some cases the drainage basin boundaries are used in defining concentration range boundaries because the quantity and quality of surface runoff is characteristic of the environment of the basin and may be entirely different from the runoff of adjacent basins. Within drainage basins, individual streams and local drainage divides define concentration boundaries. Some areas, although adjacent to each other in the same basin, have entirely different concentration ranges. For example, an area containing dissolved-solids concentrations in the 0-25 mg/1 (milligrams per litre) range may be adjacent to an area in which concentrations exceed 100 mg/1, as in the southwest part of Escambia County. Concentration boundaries in these areas were selected by extending each range about halfway between the two sampling sites, as opposed to grading an intermediate range between them without supporting data. As the data are sparse in many areas, regional concentration patterns are generalized and local variations may be expected to exist.

Florida↗
USGS2005

Coastal vulnerability assessment of National Park of American Samoa (NPSA) to sea-level rise

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within National Park of American Samoa. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined and an index value calculated for 500-meter grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. The National Park of American Samoa consists of carbonate sand and coral rubble beaches, rock cliffs and platforms, and back-reef lagoon shorelines. The areas within National Park of American Samoa that are likely to be most vulnerable to sea-level rise are areas of unconsolidated sediment where coastal slope is shallowest and wave energy is high.

American Samoa, National Park of American Samoa↗
USGS2004

Data compilation, synthesis, and calculations used for organic-carbon storage and inventory estimates for mineral soils of the Mississippi River Basin

U.S. Geological Survey investigations of environmental controls on carbon cycling in soils and sediments of the Mississippi River Basin (MRB), an area of 3.3 x 106 square kilometers (km2), have produced an assessment tool for estimating the storage and inventory of soil organic carbon (SOC) by using soil-characterization data from Federal, State, academic, and literature sources. The methodology is based on the linkage of site-specific SOC data (pedon data) to the soil-association map units of the U.S. Department of Agriculture State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) digital soil databases in a geographic information system. The collective pedon database assembled from individual sources presently contains 7,321 pedon records representing 2,581 soil series. SOC storage, in kilograms per square meter (kg/m2), is calculated for each pedon at standard depth intervals from 0 to 10, 10 to 20, 20 to 50, and 50 to 100 centimeters. The site-specific storage estimates are then regionalized to produce national-scale (STATSGO) and county-scale (SSURGO) maps of SOC to a specified depth. Based on this methodology, the mean SOC storage for the top meter of mineral soil in the MRB is approximately 10 kg/m2, and the total inventory is approximately 32.3 Pg (1 petagram = 109 metric tons). This inventory is from 2.5 to 3 percent of the estimated global mineral SOC pool.

Professional Paper↗
USGS2005

Coastal vulnerability assessment of Virgin Islands National Park (VIIS) to sea-level rise

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Virgin Islands National Park on St. John in the US Virgin Islands. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined and an index value calculated for 500-meter grid cells covering coastal areas of the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Virgin Islands National Park coast consists of carbonate sand beaches, rock cliffs, fringing reefs, and mangrove wetlands. The areas within Virgin Islands National Park that are likely to be most vulnerable to sea-level rise are areas of unconsolidated sediment where coastal slope is low, and wave energy is high.

US Virgin Islands↗
USGS1997

Water Quality Assessment of the Comal Springs Riverine System, New Braunfels, Texas, 1993-94

Comal Springs of Central Texas are the largest springs in the southwestern United States. The long-term average flow of the Comal River, which essentially is the flow from Comal Springs, is 284 cubic feet per second (ft3/s). The artesian springs emerge at the base of an escarpment formed by the Comal Springs fault. The Comal River (fig. 1) is approximately 2 miles (mi) long and is a tributary of the Guadalupe River. Most of the Comal River follows the path of an old mill race, here referred to as New Channel, then flows through a channel carved by a tributary stream (Dry Comal Creek), eventually rejoining its original watercourse. The original watercourse, here referred to as Old Channel, has been reduced to a small stream, the source of which is water diverted from Landa Lake and several springs in the channel. In addition to being an important economic resource of the region, the springs and associated river system are home to unique aquatic species such as the endangered fountain darter (Etheostoma fonticola). The Comal Springs riffle beetle (Heterelmis comalensis), which exists in the springflow channel upstream of Landa Lake, has been proposed for listing as endangered. The Comal Springs dryopid beetle (Stygoparmus comalensis) and the Peck’s cave amphipod (Stygobromus pecki) are two subterranean species associated with Comal Springs also proposed for endangered listing.

Fact Sheet↗
USGS2017

Case studies of riparian and watershed restoration in the southwestern United States—Principles, challenges, and successes

Globally, rivers and streams are highly altered by impoundments, diversions, and stream channelization associated with agricultural and water delivery needs. Climate change imposes additional challenges by further reducing discharge, introducing variability in seasonal precipitation patterns, and increasing temperatures. Collectively, these changes in a river or stream’s annual hydrology affects surface and groundwater dynamics, fluvial processes, and the linked aquatic and riparian responses, particularly in arid regions. Recognizing the inherent ecosystem services that riparian and aquatic habitats provide, society increasingly supports restoring the functionality of riparian and aquatic ecosystems. Given the wide range in types and scales of riparian impacts, approaches to riparian restoration can range from tactical, short-term, and site-specific efforts to strategic projects and long-term collaborations best pursued at the watershed scale. In the spirit of sharing information, the U.S. Geological Survey’s Grand Canyon Monitoring and Research Center convened a workshop June 23-25, 2015, in Flagstaff, Ariz. for practitioners in restoration science to share general principles, successful restoration practices, and discuss the challenges that face those practicing riparian restoration in the southwestern United States. Presenters from the Colorado River and the Rio Grande basins, offered their perspectives and experiences in restoration at the local, reach and watershed scale. Outcomes of the workshop include this Proceedings volume, which is composed of extended abstracts of most of the presentations given at the workshop, and recommendations or information needs identified by participants. The organization of the Proceedings follows a general progression from local scale restoration to river and watershed scale approaches, and finishes with restoration assessments and monitoring.

Open-File Report↗

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