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At least 1,297 records · Page 72Linked to original sources

Gauging resource exploitation by juvenile Chinook salmon (Oncorhynchus tshawytscha) in restoring estuarine habitat

In the context of delta restoration and its impact on salmonid rearing, success is best evaluated based on whether out-migrating juvenile salmon can access and benefit from suitable estuarine habitat. Here, we integrated 3 years of post-restoration monitoring data including habitat availability, invertebrate prey biomass, and juvenile Chinook salmon ( Oncorhynchus tshawytscha ) physiological condition to determine whether individuals profited from the addition of 364 ha of delta habitat in South Puget Sound, Washington, United States. Productivity in the restored mudflat was comparable to reference sites 3 years after dike removal, surpassing a mean total of 6 million kJ energy from invertebrate prey. This resulted from the development of a complex network of tidal channels and a resurgence in dipteran biomass that was unique to the restoration area. Consequently, a notable shift in invertebrate consumption occurred between 2010 and 2011, whereby individuals switched from eating primarily amphipods to dipteran flies; however, dietary similarity to the surrounding habitat did not change from year to year, suggesting that this shift was a result of a change in the surrounding prey communities. Growth rates did not differ between restored and reference sites, but catch weight was positively correlated with prey biomass, where greater prey productivity appeared to offset potential density-dependent effects. These results demonstrate how the realized function of restoring estuarine habitat is functionally dependent. High prey productivity in areas with greater connectivity may support healthy juvenile salmon that are more likely to reach the critical size class for offshore survival.

Washington↗

Test of salt marsh as a site of production and export of fish biomass with implications for impoundment management and restoration

Salt marshes are among the most productive ecosystems in the world, and although they are thought to enhance the productivity of open estuarine waters, the mechanism by which energy transfer occurs has been debated for decades. One possible mechanism is the transfer of saltmarsh production to estuarine waters by vagile fishes and invertebrates. Saltmarsh impoundments in the Indian River Lagoon, Florida, that have been reconnected to the estuary by culverts provide unique opportunities for studying marsh systems with respect to aquatic communities. The boundaries between salt marshes and the estuary are clearly defined by a system of dikes that confine fishes into a known area, and the exchange of aquatic organisms are restricted to culverts where they may be easily sampled. A multi-gear approach was used monthly to estimate fish standing stock, fish ingress/egress, and predation. Changes in saltmarsh fish abundance, and exchange with the estuary reflected the seasonal pattern of marsh flooding in the xv northern Indian River Lagoon system. During a six month period of marsh flooding, saltmarsh fishes had continuous access to marsh food resources. Piscivorous fishes regularly entered the marsh via creeks and ditches to prey upon marsh fishes, and piscivorous birds aggregated following major fish migrations to the marsh surface or to deep habitats. As water levels receded in winter, saltmarsh fishes concentrated into deep habitats and migration to the estuary ensued. The monthly estimates of fish standing stock, net fish ingress, and predation were used to develop a biomass budget to estimate annual production of fishes and the relative yield to predatory fish, birds, and direct migration to the estuary. Annual production of saltmarsh fishes was estimated to be 17.7 g·m-2 salt marsh, which falls within the range of previously reported values for estuarine fish communities. The relative yields were at least 21% to piscivorous fishes, 14% to piscivorous birds, and 32% to export. Annual export of fish biomass was 5.6 g fish·m-2 salt marsh, representing about 2% of saltmarsh primary production. Saltmarsh fishes convert marsh production to high quality vagile biomass (fishes concentrate energy, protein, and nutrients as body mass) and move this readily useable production to the estuary, providing an efficient link between salt marshes and estuarine predators.

Thesis↗

San Diego Multiple Species Conservation Program (MSCP) Rare Plant Monitoring Review and Revision

Introduction The San Diego Multiple Species Conservation Program (MSCP) was developed for the conservation of plants and animals in the south part of San Diego County, under the California Natural Community Conservation Planning Act of 1991 (California Department of Fish and Game) and the Federal Endangered Species Act of 1973, as amended (16 U.S. Code 1531-1544.) The Program is on the leading edge of conservation, as it seeks to both guide development and conserve at-risk species with the oversight of both State and Federal agencies. Lands were identified for inclusion in the MSCP based on their value as habitat for at-risk plants or plant communities (Natural Community Conservation Planning, 2005). Since its inception in the mid-1990s the Program has protected over 100,000 acres, involving 15 jurisdictions and the U.S. Fish and Wildlife Service (USFWS) and California Department of Fish and Game (CDFG) in the conservation of 87 taxa. Surveys for covered species have been conducted, and management and monitoring have been implemented at some high priority sites. Each jurisdiction or agency manages and monitors their conservation areas independently, while collaborating regionally for long-term protection. The San Diego MSCP is on the forefront of conservation, in one of the most rapidly growing urban areas of the country. The planning effort that developed the MSCP was state-of-the-art, using expert knowledge, spatial habitat modeling, and principles of preserve design to identify and prioritize areas for protection. Land acquisition and protection are ahead of schedule for most jurisdictions. Surveys have verified the locations of many rare plant populations known from earlier collections, and they provide general information on population size and health useful for further conservation planning. Management plans have been written or are in development for most MSCP parcels under jurisdictional control. Several agencies are developing databases for implementation and management tracking. In many ways this program is at the cutting edge of regional conservation, testing concepts, developing techniques, and demonstrating conservation effectiveness in new and uncharted ways. Periodic program review is crucial to the continued success of the program, as it moves from a phase of planning and acquisition to one of management and monitoring. Ecological monitoring is the key to assessing the success of the protection and management implemented at each individual reserve and for the MSCP as a whole. The ultimate goal of the Program is conservation of at-risk taxa and their habitats, as well as underlying ecological processes that contribute to sustainability of the ecosystem. Monitoring guidelines and timetables were developed by Ogden Environmental and Energy Services Co., Inc. (1996), and reviewed by Conservation Biology Institute (2001). The Program is in transition now, from the initial stage of land protection to one of land management and monitoring to determine population responses to management regimes. Several agencies have already invested substantial effort in status and trend monitoring, while others are developing their monitoring plans. Management is ongoing at several sites. With both management and monitoring, collaboration and coordination among jurisdictions can be especially fruitful in conserving resources and maximizing success.

Scientific Investigations Report↗

Variability of lipids and fatty acids in Pacific walrus blubber

The variability of lipid content and fatty acid (FA) composition across blubber depth and body sites are important considerations for condition and diet studies of marine mammals. We investigated lipid and FA variability among inner and outer blubber layers, three body sites, four study years, and lactation status of adult female Pacific walruses ( Odobenus rosmarus divergens ) using blubber samples collected from subsistence-harvested walruses in spring 2007–2010. Percent lipid content did not differ between the inner and outer blubber layers at the rump, flank, or sternum of walruses. Although FA composition differed between the inner and outer blubber layers, the difference was consistent across body sites, and differences between layers within individual FAs were small (<2%). Lipid content at the sternum of lactating females was 6% higher than non-lactating females, consistent with known variation in body condition among these reproductive classes. Across study years, lipid content varied 18% and individual FAs varied 6%, likely reflecting population-level interannual variability in energy budgets and small differences in diet among years. Consistency in blubber lipid content across blubber depth and body sites and detectable variation in blubber lipid content among reproductive classes and years suggests the potential for lipid content to be a useful indicator of walrus body condition. In addition to information on condition, FA composition of blubber samples could potentially provide insights into changes in walrus diet that may be expected to occur from changes in their access to prey resources resulting from continued sea ice loss.

Frontiers in Marine Science↗

Colloid transport in saturated porous media: Elimination of attachment efficiency in a new colloid transport model

A colloid transport model is introduced that is conceptually simple yet captures the essential features of colloid transport and retention in saturated porous media when colloid retention is dominated by the secondary minimum because an electrostatic barrier inhibits substantial deposition in the primary minimum. This model is based on conventional colloid filtration theory (CFT) but eliminates the empirical concept of attachment efficiency. The colloid deposition rate is computed directly from CFT by assuming all predicted interceptions of colloids by collectors result in at least temporary deposition in the secondary minimum. Also, a new paradigm for colloid re-entrainment based on colloid population heterogeneity is introduced. To accomplish this, the initial colloid population is divided into two fractions. One fraction, by virtue of physiochemical characteristics (e.g., size and charge), will always be re-entrained after capture in a secondary minimum. The remaining fraction of colloids, again as a result of physiochemical characteristics, will be retained “irreversibly” when captured by a secondary minimum. Assuming the dispersion coefficient can be estimated from tracer behavior, this model has only two fitting parameters: (1) the fraction of the initial colloid population that will be retained “irreversibly” upon interception by a secondary minimum, and (2) the rate at which reversibly retained colloids leave the secondary minimum. These two parameters were correlated to the depth of the Derjaguin-Landau-Verwey-Overbeek (DLVO) secondary energy minimum and pore-water velocity, two physical forces that influence colloid transport. Given this correlation, the model serves as a heuristic tool for exploring the influence of physical parameters such as surface potential and fluid velocity on colloid transport.

Water Resources Research↗

Coal resources of the United States, A progress report, November 1, 1950

Interest in the quantity and quality of the coal reserves of the United States has increased greatly since the end of World War II, principally because of the growing realization that the ultimate reserves of petroleum and natural gas, although largely undefined, still. have finite limits. With the greatly increased use of petroleum and natural gas, it has become further apparent that the reserves of these two fuels, whatever their ultimate limits may prove to be, are being consumed at a rate far surpassing that anticipated a few years ago. At some time in the future, therefore, the contribution of coal to the total production of energy in this country must inevitably be enlarged to include some of the needs now served by petroleum and natural gas. Although coal-bearing rocks cover 14 percent of the total area of the United States (fig. 1) and contain enormous reserves, it is equally apparent that reserves of coal also have limits. In the extensively mined sections in the East it is already increasingly difficult to locate new areas containing thick beds of high-rank and high-quality coal to replace areas that have been mined out. Furthermore, a considerable part of the total reserves of the United States consists of coal of lignite and subbituminous ranks and coal contained in thin beds that can be mined only with great difficulty and expense. At the present time, therefore, the depletion of reserves of high-rank and high-quality coal, particularly the Eastern coal that is suitable for the manufacture of metallurgical coke, is a more serious problem than the percentage depletion of the total coal reserves. Recognizing the need for more detailed estimates of coal reserves than those that have been available in the past, the U. S. Geological Survey is now preparing a reappraisal of the coal reserves of the United States in which primary emphasis is placed on the amounts of coal in separate categories according to rank,thickness of coal, and thickness of overburden. Many of the state geological surveys in coal-producing areas are also preparing new appraisals of coal reserves. The increasing volume of geologic data available on the occurrence of coal and the detailed and careful methods now employed in calculating reserves should ultimately provide a more reliable estimate for the coal reserves of the United States than has been obtainable previously, although much additional work remains to be done.

Circular↗

A global satellite assisted precipitation climatology

Accurate representations of mean climate conditions, especially in areas of complex terrain, are an important part of environmental monitoring systems. As high-resolution satellite monitoring information accumulates with the passage of time, it can be increasingly useful in efforts to better characterize the earth's mean climatology. Current state-of-the-science products rely on complex and sometimes unreliable relationships between elevation and station-based precipitation records, which can result in poor performance in food and water insecure regions with sparse observation networks. These vulnerable areas (like Ethiopia, Afghanistan, or Haiti) are often the critical regions for humanitarian drought monitoring. Here, we show that long period of record geo-synchronous and polar-orbiting satellite observations provide a unique new resource for producing high resolution (0.05&deg;) global precipitation climatologies that perform reasonably well in data sparse regions. Traditionally, global climatologies have been produced by combining station observations and physiographic predictors like latitude, longitude, elevation, and slope. While such approaches can work well, especially in areas with reasonably dense observation networks, the fundamental relationship between physiographic variables and the target climate variables can often be indirect and spatially complex. Infrared and microwave satellite observations, on the other hand, directly monitor the earth's energy emissions. These emissions often correspond physically with the location and intensity of precipitation. We show that these relationships provide a good basis for building global climatologies. We also introduce a new geospatial modeling approach based on moving window regressions and inverse distance weighting interpolation. This approach combines satellite fields, gridded physiographic indicators, and in situ climate normals. The resulting global 0.05&deg; monthly precipitation climatology, the Climate Hazards Group's Precipitation Climatology version 1 (CHPclim v.1.0, http://dx.doi.org/10.15780/G2159X ), is shown to compare favorably with similar global climatology products, especially in areas with complex terrain and low station densities.

Earth System Science Data↗

Estimation of evaporation from Ned Wilson Lake, Flat Tops Wilderness Area, Colorado

As part of an effort to define the hydrology and water quality of Ned Wilson Lake, evaporation rates were estimated for the summer periods of 1983 and 1984. Mass-transfer and energy-budget techniques and the Morton model were used to estimate evaporation using data collected at the lake and data collected at a meteorological station 0.1 mile from the lake. The estimate of evaporation for July 29 through September 27, 1983, using the mass-transfer technique, was 9.50 inches; the estimate using the energy-budget technique was 8.10 inches; the estimate using the Morton model was 9.90 inches. The evaporation estimate for July 18 through September 25, 1984, using the mass-transfer technique was 8.71 inches; the estimate using the energy-budget technique was 7.88 inches; the estimate using the Moron model was 10.49 inches. These estimates will provide values to be used in future analyses of the interaction of lake and groundwater; however, refinement of data collection will be necessary to determine specifically the rate of evaporation. (USGS)

Water-Resources Investigations Report↗

On the sustainability of inland fisheries: Finding a future for the forgotten

At present, inland fisheries are not often a national or regional governance priority and as a result, inland capture fisheries are undervalued and largely overlooked. As such they are threatened in both developing and developed countries. Indeed, due to lack of reliable data, inland fisheries have never been part of any high profile global fisheries assessment and are notably absent from the Sustainable Development Goals. The general public and policy makers are largely ignorant of the plight of freshwater ecosystems and the fish they support, as well as the ecosystem services generated by inland fisheries. This ignorance is particularly salient given that the current emphasis on the food-water-energy nexus often fails to include the important role that inland fish and fisheries play in food security and supporting livelihoods in low-income food deficit countries. Developing countries in Africa and Asia produce about 11 million tonnes of inland fish annually, 90 % of the global total. The role of inland fisheries goes beyond just kilocalories; fish provide important micronutrients and essentially fatty acids. In some regions, inland recreational fisheries are important, generating much wealth and supporting livelihoods. The following three key recommendations are necessary for action if inland fisheries are to become a part of the food-water-energy discussion: invest in improved valuation and assessment methods, build better methods to effectively govern inland fisheries (requires capacity building and incentives), and develop approaches to managing waters across sectors and scales. Moreover, if inland fisheries are recognized as important to food security, livelihoods, and human well-being, they can be more easily incorporated in regional, national, and global policies and agreements on water issues. Through these approaches, inland fisheries can be better evaluated and be more fully recognized in broader water resource and aquatic ecosystem planning and decision-making frameworks, enhancing their value and sustainability for the future.

Ambio↗

Database of biodiversity, habitat, and aquatic-resource quantification tools used in market-based conservation — 2022 update

Market-based conservation makes use of economic incentives to promote actions that avoid, minimize, or compensate for detrimental effects on natural resources and the environment. Examples of market-based conservation mechanisms include aquatic-resource (such as, streams, wetlands, and estuaries) compensatory mitigation, conservation banking, habitat exchanges, and payments for ecosystem services. A critical component in the operation of these market-based conservation mechanisms is the methods (hereafter referred to as “quantification tools”) used to assess existing (sometimes referred to as “baseline”) or potential site conditions. Quantification tools are used to assign values to the benefits provided by preservation, restoration, or enhancement actions, as well as the negative effects of human activities (for example, infrastructure development, energy extraction, and anthropogenic disasters). In 2018, the U.S. Geological Survey (USGS) published a database describing the attributes of 69 quantification tools developed for United States conservation markets. The database focused on tools used for species-based mitigation, payments for ecosystem services, and ecolabel programs (Chiavacci and Pindilli, 2020). Recently, the USGS, in collaboration with the U.S. Environmental Protection Agency, revised the original database by updating the existing tool information, adding newly developed tools, and broadening the scope to include tools developed for compensatory mitigation under the Clean Water Act Section 404 Regulatory Program.

Fact Sheet↗

Case study - Dynamic pressure-limited capacity and costs of CO2 storage in the Mount Simon sandstone

Widespread deployment of carbon capture and storage (CCS) is likely necessary to be able to satisfy baseload electricity demand, to maintain diversity in the energy mix, and to achieve climate and other objectives at the lowest cost. If all of the carbon dioxide (CO 2 ) emissions from stationary sources (such as fossil-fuel burning power plants, and other industrial plants) in the United States needed to be captured and stored, it could be possible to store only a small fraction of this CO 2 in oil and natural gas reservoirs, including as a result of CO 2 utilization for enhanced oil recovery. The vast majority would have to be stored in saline-filled reservoirs (Dahowski et al., 2005). Given a lack of long-term commercial-scale CCS projects, there is considerable uncertainty in the risks, dynamic capacity, and their cost implications for geologic storage of CO 2 . Pressure buildup in the storage reservoir is expected to be a primary source of risk associated with CO 2 storage, and could severely limit CO 2 injection rates (dynamic storage capacities). Most cost estimates for commercial-scale deployment of CCS estimate CO 2 storage costs under assumed availability of a theoretical capacity to store tens, hundreds, or even thousands of gigatons of CO 2 , without considering geologic heterogeneities, pressure limitations, or the time dimension. This could lead to underestimation of the costs of CO 2 storage (Anderson, 2017). This paper considers the impacts of pressure limitations and geologic heterogeneity on the dynamic CO 2 storage capacity and storage (injection) costs. In the U.S. Geological Survey (USGS)’s National Assessment of Geologic CO 2 Storage Resources (USGS, 2013), the mean estimate of the theoretical storage capacity in the Mount Simon Sandstone was about 94 billion metric tons of CO 2 . However, our results suggest that the pressure-limited capacity after 50 years of injection could be only about 4% of the theoretical geologic storage capacity in this formation. Because this is far less than emissions of CO 2 from stationary sources in the region around the Mount Simon Sandstone, the costs to accommodate the potential annual demand for CO 2 storage in this formation could be significantly greater than current estimates. Our results could have implications for how long and to what extent decision makers can expect to be able to deploy CCS before transitioning to other low- or zero-carbon energy technologies.

Conference Paper↗

Report of committee on glaciers, April 1939

The Committee on Glaciers at present is constituted as follows: Harry Fielding Reid—Professor‐Emeritus of Geology, Johns Hopkins University (former member of the International Glacier Commission), 608 Cathedral Street, Baltimore, Maryland William H. Hobbs—Professor‐Emeritus of Geology, University of Michigan (until recently Vice‐ President of the International Glacier Commission, at present associate member), Ann Arbor, Michigan J. E. Church—Professor of Classics, University of Nevada (President of the International Commission of Snow, and Chairman of the Committee on Snow of the Section of Hydrology, American Geophysical Union), Reno, Nevada Colonel Lawrence Martin—Chief of the Division of Maps, Library of Congress, Washington, D. C. Wm. Osgood Field, Jr.—Explorer, 18 West Twelfth Street, New York, N.Y. Earl A. Trager—Chief of the Naturalist Division, National Park Service, Washington, D. C. Glenn L. Parker—District Engineer, Water Resources Branch, United States Geological Survey, 406 Federal Building, Tacoma, Washington Oliver Kehrlein—Chairman, Committee on Glacier Studies, Sierra Club, 1050 Mills Tower, San Francisco, California Kenneth N. Phillips—Associate Hydraulic Engineer, Water Resources Branch, United States Geological Survey, Chairman, Research Committee of the Mazamas, 606 Post‐Office Building, Portland, Oregon William S. Cooper—Professor of Botany, University of Minnesota, Minneapolis, Minnesota Gerald FitzGerald, Senior Topographic Engineer, Alaska Branch, United States Geological Survey, Washington, D.C. Laurence M. Gould, Professor of Geology, Carleton College, Northfield, Minnesota François E. Matthes, Chairman , Senior Geologist, Section of Glacial Geology, United States Geological Survey (titular member of the International Glacier Commission), Washington, D.C. In 1938, as in previous years, the Committee devoted its energies primarily to the collecting of data on the variations in length and volume of American glaciers, it being felt that the maintenance of a continuous record of these variations is of prime importance, not only to hydrology and glaciology, but, as has become increasingly evident recently, also to climatology, geomorphology, geography, ecology, history, and archaeology. As the time available for the work of the Committee is limited and does not permit covering the entire field of glaciology, it seems best to devote it before all else to this line of research which yields results of value to so many different sciences. Besides, the gathering of data on glacier‐oscillations is not a one‐man job that can be taken up or dropped at convenience from time to time, but is an organized and far‐flung enterprise whose success depends upon the faithful cooperation of many volunteer workers located in different parts of the country. Such an enterprise, once launched, must be kept running or it will disintegrate and the precious enthusiasm of the field‐workers will be lost.

Eos, Transactions, American Geophysical Union↗

The added complications of climate change: Understanding and managing biodiversity and ecosystems

Ecosystems around the world are already threatened by land-use and land-cover change, extraction of natural resources, biological disturbances, and pollution. These environmental stressors have been the primary source of ecosystem degradation to date, and climate change is now exacerbating some of their effects. Ecosystems already under stress are likely to have more rapid and acute reactions to climate change; it is therefore useful to understand how multiple stresses will interact, especially as the magnitude of climate change increases. Understanding these interactions could be critically important in the design of climate adaptation strategies, especially because actions taken by other sectors (eg energy, agriculture, transportation) to address climate change may create new ecosystem stresses.

Frontiers in Ecology and the Environment↗

Relations between basin characteristics and stream water chemistry in alpine/subalpine basins in Rocky Mountain National Park, Colorado

Relations between stream water chemistry and topographic, vegetative, and geologic characteristics of basins were evaluated for nine alpine/subalpine basins in Rocky Mountain National Park, Colorado, to identify controlling parameters and to better understand processes governing patterns in stream water chemistry. Fractional amounts of steep slopes (≥30°), unvegetated terrain, and young surficial debris within each basin were positively correlated to each other. These terrain features, which commonly occur on steep valley side slopes underlain by talus, were negatively correlated with concentrations of base cations, silica, and alkalinity and were positively correlated with nitrate, acidity, and runoff. These relations might result from the short residence times of water and limited soil development in the talus environment, which limit chemical weathering and nitrogen uptake. Steep, unvegetated terrains also tend to promote high Ca/Na ratios in stream water, probably because physical weathering rates in those areas are high. Physical weathering exposes fresh bedrock that contains interstitial calcite, which weathers relatively quickly. The fractional amounts of subalpine meadow and, to a lesser extent, old surficial debris in the basins were positively correlated to concentrations of weathering products and were negatively correlated to nitrate and acidity. These relations may reflect more opportunities for silicate weathering and nitrogen uptake in the lower‐energy environments of the valley floor, where soils are finer‐grained, older, and better developed and slopes are relatively flat. These results indicate that in alpine/subalpine basins, slope, vegetation (or lack thereof), and distribution and age of surficial materials are interrelated and can have major effects on stream water chemistry.

Colorado↗

Reconnaissance of ground-water resources in the Mountain Home plateau area, southwest Idaho

The Mountain Home plateau area occupies approximately 1,220 square miles of the western Snake River Plain in southwestern Idaho. About 40,000 acres are presently (1977) irrigated with ground water, about 30,000 acres with surface water. An estimated 450,000 acres are potentially irrigable, if water is available. Development of ground-water re- sources has caused water-level declines in several places. Largest declines are south of Mountain Home, where water levels dropped more than 20 feet in the last 9 years. Ground water in the area occurs primarily under water-table conditions. Perched-water zones are present in several locations. The most productive aquifer in the eastern part of the plateau is basalt of the Bureau Formation of the Idaho Group. In the western part, the most productive aquifers are sand and gravel of the older terrace gravel lithologic unit and the Idaho Group. Recharge to the ground-water system is water from the Boise River drainage basin, precipitation on the plateau and adjacent mountains, and leakage from irrigation structures. Ground-water movement is generally south or southwest. Natural ground-water discharge from the plateau is about 18,000 acre-feet annually. The chemical composition of the ground water generally reflects water characteristics in the area of the source of recharge and, for the most part, is good. Deuterium and oxygen-18 isotope analyses suggest that the water at the lower end of the ground-water flow system underlying the plateau was recharged a long time ago, although climatic conditions then were similar to current conditions in the Boise River basin. Additional large-scale ground-water development will probably result in economically prohibitive pumping lifts, which also would consume excessive amounts of energy. Therefore, large-scale new agricultural development would depend heavily on the availability of surface water. However, one or several deep test holes, in selected places, could help answer some questions about the occurrence of ground water and perhaps encourage further exploration for untapped deep artesian aquifers. The occurrence of perched-water zones beneath lands irrigated by surface water suggests that more zones of this type could develop if water is imported into the area to irrigate additional lands, and if the efficiency of the present distribution systems remains unchanged.

Idaho↗

Statewide summary for Alabama

Alabama is over 132,000 km 2 (51,000 miles 2 ) in area, 483 km (300 miles) long, and 322 km (200 miles) wide (Copeland, 1968). Coastal Alabama comprises Mobile and Baldwin Counties and the surrounding State waters in the Gulf of Mexico (Figure 1; O’Neil and Mettee, 1982). It is part of both the East Gulf Coastal Plain section of the Coastal Plain province and the Mississippi-Alabama shelf section of the Continental Shelf province. Within the East Gulf Coastal Plain section, Alabama’s coastal land falls within the Southern Pine Hills and Coastal Lowlands subdivisions. The Southern Pine Hills subdivision is a sloping landscape composed of sand and clay. Its elevation varies from approximately 30 m (98 ft) near the coast to over 90 m (295 ft) in the northern areas of the two coastal counties. The Coastal Lowlands subdivision is a flat to slightly undulating plain with creeks, rivers, estuaries, and marshes leading to the surrounding bays and the Gulf of Mexico. Offshore Alabama is part of the Mississippi-Alabama section of the Continental Shelf. Barrier islands and spits in coastal Alabama include Dauphin Island, Fort Morgan Peninsula, and Perdido Key. Dauphin Island consists of a beach with dunes on the Gulf side and beaches and marshes on the north side. It was once over 24 km long, but after Hurricane Katrina it has been broken into two distinct islands. Fort Morgan Peninsula is attached to the eastern mainland and extends westward between Mobile Bay and the Gulf of Mexico. A large beach exists on the gulf side, with numerous lagoons and marshes on the bayside. Perdido Key is a narrow peninsula on the easternmost Alabama coast near the Alabama-Florida border, south of Perdido Bay. It consists of beaches and high dunes, with some marshes on the lagoon side of the peninsula. Mobile Bay, parts of Mississippi Sound, Perdido Bay, and many smaller rivers and streams are the main bodies of water in coastal Alabama. Mobile Bay, a submerged river valley, is the largest at 1,070 km 2 (413 miles 2 ) in area and 51.5 km (32 miles) in length (Mobile Bay NEP, 2008). Mobile Bay is 37 km (23 miles) wide at its maximum width near the opening to the Gulf of Mexico at the south end of the bay, and 16.1 km (10 miles) wide at the city of Mobile (Mobile Bay NEP, 2003; Mobile Bay NEP, 2008). It is remarkably shallow with an average depth of 3 m (10 ft), yet it discharges approximately 1,755.6 m 3 (62,000 ft 3 ) of water every second on average (Mobile Bay NEP, 2008). Mississippi Sound runs parallel to the coasts of Mississippi and part of Alabama. The length of the Alabama portion of Mississippi Sound is approximately 26 km (16.2 miles) from the Dauphin Island bridge to the Mississippi-Alabama State line (O’Neil and Mettee, 1982). Dauphin Island separates the sound from the Gulf of Mexico. The sound drains into the Gulf of Mexico west of Dauphin Island at Petit Bois Pass, which is approximately 8 km (5 miles) wide. Mississippi Sound averages approximately 3.5 m (11.5 ft) in depth. Salt marshes, large areas of wetland scrub-shrub, and tidal creeks characterize the northern shore of Mississippi Sound, and the southern shore is composed of sandy barrier islands. Perdido Bay is located at the boundary of Baldwin County and Florida’s Escambia County. It is approximately 27 km (16.8 miles) long, 5 km (3 miles) at its widest point, and, on average, 2.4 m (7.9 ft) deep. The major fresh-water resource in coastal Alabama is the Mobile River, formed by the confluence of the Alabama and Tombigbee Rivers. The watershed for the Mobile River is approximately 111,369 km 2 (43,000 miles 2 ) large and includes parts of Alabama, Georgia, Mississippi, and Tennessee (Handley et al., 2007). Parts of Alabama and the Florida Panhandle drain into the Perdido River basin and western coastal Alabama drains into the Escatawpa River. Emergent wetlands offer valuable ecological services in coastal Alabama. Marshes provide extensive plant material, which provides energy to the detritus-based estuarine ecological system (O’Neil et al., 1983). They provide habitat for many organisms, including shrimp and crabs, whose harvest is a major industry in coastal Alabama. Marshes provide habitat for refuge, feeding, breeding, and spawning. They also remove excess nutrients from water and contribute to erosion control. Degradation of marshes by pollutants, sediments, and other impacts decreases productivity of the entire estuarine ecosystem. Among the nation’s states, Alabama ranks fifth in number of different species (144 endemic species), second in number of extinctions that have already occurred (90 extinct species) and fourth in number of species at risk for extinction (14.8% at risk out of 4,533 total species; Stein, 2002). Many species of wildlife benefit from the wetland habitats in coastal Alabama. Numerous bird species can be found in coastal Alabama emergent marshes, which provide habitat for shore- and wading-birds that inhabit salt or brackish water coastal environments (Anderson et al., 1981). Colonial seabirds nest on coastal Alabama’s islands, the mainland, and dredge disposal sites (Cooley, 1987). The Mobile-Tensaw Delta and Mobile Bay are the state’s primary migratory waterfowl coastal wintering areas (U.S. Fish and Wildlife Service, 1982). The shallow waters, abundance of fish, and vegetative cover in emergent marsh contribute to excellent waterfowl habitat. Emergent wetlands in Alabama also provide habitat for a multitude of endangered species, including various species of raptors and wading- and shorebirds (O’Neil et al., 1983).

Alabama↗

Well log and 2D seismic data character of the Wilcox Group in south-central Louisiana

Well logs and 2D seismic data were used to interpret the depth and morphology of potential Paleocene and lower Eocene Wilcox Group slope and basin-floor reservoirs in south-central Louisiana. These may occur in a poorly explored area previously estimated by the U.S. Geological Survey to contain a mean undiscovered conventional resource potential of 26,398 billion cubic feet of gas and 423 million barrels of natural gas liquids. The Wilcox Group is 15,000 to 26,000 feet deep in south-central Louisiana. Previously published paleogeographic maps suggest the sediment transport direction during the Paleocene and lower Eocene was west to east, parallel to the relict Cretaceous shelf margin, and north to south due to the development of the Holly Springs delta system in Louisiana. Inclined reflectors on the 2D seismic data suggest high-energy deposition of clastic sediments. There is minimal well control downdip of currently productive areas. The Wilcox Group is productive in updip areas of Texas and Louisiana from fluvial, deltaic, and near-shore marine shelf sandstones. The reported presence of porous sandstones at 29,000 feet within the Wilcox Group containing about 200 feet of gas in the Davy Jones 1 discovery well in the offshore Louisiana South Marsh Island area illustrates a sand-rich system developed during the Paleocene and early Eocene. This study describes some of the well log and reflection seismic data characteristics of the slope and basin-floor reservoirs with gas-discovery potential that may be in the area between the producing trend onshore Louisiana and the offshore discovery.

Louisiana↗

Regional evaluation of evapotranspiration in the Everglades

Nine sites in the Florida Everglades were selected and instrumented for collection of data necessary for evapotranspiration-determination using the Bowen-ratio energy-budget method. The sites were selected to represent the sawgrass or cattail marshes, wet prairie, and open-water areas that constitute most of the natural Everglades system. At each site, measurements necessary for evapotranspiration (ET) calculation and modeling were automatically made and stored on-site at 15- or 30-minute intervals. Data collected included air temperature and humidity at two heights, wind speed and direction, incoming solar radiation, net solar radiation, water level and temperature, soil moisture content, soil temperature, soil heat flux, and rainfall. Data summarized in this report were collected from January 1996 through December 1997, and the development of site-specific and regional models of ET for this period is described. Latent heat flux is the energy flux density equivalent of the ET rate. Modified Priestley-Taylor models of latent heat flux as a function of selected independent variables were developed at each site. These models were used to fill in periods of missing latent heat flux measurement, and to develop regional models of the entire Everglades region. The regional models may be used to estimate ET in wet prairie, sawgrass or cattail marsh, and open-water portions of the natural Everglades system. The models are not applicable to forested areas or to the brackish areas adjacent to Florida Bay. Two types of regional models were developed. One type of model uses measurements of available energy at a site, together with incoming solar energy and water depth, to estimate hourly ET. This available-energy model requires site data for net radiation, water heat storage, and soil heat flux, as well as data for incoming solar radiation and water depth. The other type of model requires only incoming solar energy, air temperature, and water depth data to provide estimates of hourly ET. The second model thus uses data that are more readily available than the data required for the available-energy model. Computed ET mean annual totals for all nine sites for the 1996-97 period ranged from 42.4 inches per year at a site where the water level is below land surface for several months each year to 57.4 inches per year at an open-water site with no emergent vegetation. Although the density of photosynthetically-active plant leaves has been shown to relate directly to ET in some studies, it does not appear to relate directly to ET in the Everglades, based on comparison of annual ET data with leaf-area index, defined as the Normalized Difference Vegetation Index (NDVI), data from satellite imagery. NDVI and ET appear to be inversely related in the Everglades. The greatest ET rates occurred at open-water sites where the NDVI data indicated the lowest leaf-area index. Among the remaining vegetated sites, there is no clear relation between ET and NDVI, though the highest ET rate corresponded to the lowest NDVI and one of the lowest ET rates corresponded to the highest NDVI value. The variation in ET follows a seasonal pattern, with lowest monthly ET totals occurring in December through February, and highest ET occurring in May through August. The greatest range in monthly ET among all nine sites for the 2-year period occurred at site 3: from 1.81 inches in December 1997 to 6.84 inches in July 1996. A study to compare the Bowen-ratio/energy balance method of ET measurement with the eddy-correlation method was done at one site from June 22, 1998, through September 28, 1998. This comparison indicated that both methods gave comparable values of the Bowen ratio, but there was a considerable difference in available energy measured by the two methods. The mean of all 30-minute measured turbulent heat fluxes from the eddy-correlation apparatus for June 22 through September 29, 1998, was 137.4 watts per square meter, and the mean of the corresponding measured energy was 163.6 watts per square meter, or about 20 percent greater. The disagreement in mean energy fluxes measured by the two methods is problematical and is not fully understood. Although the difference seems to be related to friction velocity, and is practically non-existent at values of friction velocity greater than 0.3 meter per second, the "correctness" of either method cannot be determined with the data available.

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