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At least 379 records · Page 21Linked to original sources
USGS2021

Maps of the Arctic Alaska boundary area as defined by the U.S. Arctic Research and Policy Act—Including geospatial characteristics of select marine and terrestrial features

This pamphlet presents a series of general reference maps showing relevant geospatial features of the U.S. Arctic boundary as defined by the U.S. Congress since 1984. The first generation of the U.S. Arctic Research and Policy Act (ARPA) boundary maps was originally formatted and published in 2009 by a private firm contracted with the National Science Foundation and the U.S. Arctic Research Commission. Recognizing the steadily increasing relevance of Arctic issues to national and global affairs that requires more functional projections and online tools, the U.S. Geological Survey (USGS) Alaska Regional Office and the National Geospatial Technical Operations Center developed this updated series of ARPA boundary maps. Map sheet 1 shows the ARPA boundary as it relates to Alaska and marine features of the Bering Sea. Map sheet 2 shows the ARPA boundary from a circumpolar perspective. Map sheet 3 shows the national boundary of the U.S. 200-nautical-mile Exclusive Economic Zone through the Bering, Chukchi, and Beaufort Seas, facilitating Arctic domain awareness and more consistent territorial assessments of the U.S. Arctic. Map sheet 4 shows, in poster-size detail, the ARPA boundary as it relates to terrestrial features of Arctic Alaska north of the Yukon and Kuskokwim Rivers. Map sheet 5 shows, in poster-size detail, the ARPA boundary as it relates to marine and terrestrial features of the Aleutian Islands. These new maps collectively illustrate several value-added attributes, including updated bathymetry and shoreline refinements, demographic information, international borders and offshore territorial claims, Alaska conservation areas, Alaska land cover, Alaska terrestrial shaded relief, annual sea ice maximum extent, annual circumpolar 10-degree-Celsius isotherm, location of active volcanoes, and updated geospatial information. The static PDF-file maps offer value as standalone products but are intended for use with a potential interactive website that can be sourced by annual data updates, allowing users to access the various map layers in a dynamic up-to-date environment.

Alaska↗
USGS2009

Surface-Water and Groundwater Interactions along the Withlacoochee River, West-Central Florida

A study of the Withlacoochee River watershed in west-central Florida was conducted from October 2003 to March 2007 to gain a better understanding of the hydrology and surface-water and groundwater interactions along the river. The Withlacoochee River originates in the Green Swamp area in north-central Polk County and flows northerly through seven counties, emptying into the Gulf of Mexico. This study includes only the part of the watershed located between the headwaters in the Green Swamp and the U.S. Geological Survey gaging station near Holder, Florida. The Withlacoochee River within the study area is about 108 miles long and drains about 1,820 square miles. The Withlacoochee River watershed is underlain by thick sequences of carbonate rock that are covered by thin surficial deposits of unconsolidated sand and sandy clay. The clay layer is breached in many places because of the karst nature of the underlying limestone, and the degree of confinement between the Upper Florida aquifer and the surficial aquifer is highly variable throughout the watershed. The potential for movement of water from the surface or shallow deposits to deeper deposits, or from deeper deposits to the shallow deposits, exists throughout the Withlacoochee River watershed. Water levels were higher in deeper Upper Floridan aquifer wells than in shallow Upper Floridan aquifer wells or surficial aquifer wells at 11 of 19 paired or nested well sites, indicating potential for discharge to the surface-water system. Water levels were higher in shallow Upper Floridan aquifer or surficial aquifer wells than in deeper Upper Floridan aquifer wells at five other sites, indicating potential for recharge to the deeper Upper Floridan aquifer. Water levels in the surficial aquifer and Upper Floridan aquifer wells at the remaining three sites were virtually the same, indicating little or no confinement at the sites. Potentiometric-surface maps of the Upper Floridan aquifer indicate the pattern of groundwater flow in the aquifer did not vary greatly from season to season during the study. Potentiometric contours indicate groundwater discharge to the river in the vicinity of Dade City and Lake Panasoffkee. During dry periods, groundwater from the underlying Upper Floridan aquifer contributed to the flow in the river. During wet periods, streamflow had additional contributions from runoff and input from tributaries. Groundwater has a greater effect on streamflow downstream from the Dade City station than upstream from the Dade City station because confinement between surficial deposits and the Upper Floridan aquifer is greater in the Green Swamp area than in downstream areas. Estimates of streamflow gains and losses were made along the Withlacoochee River during base-flow conditions in May 2004, April 2005, and April 2006. Base flow was higher in April 2005 than in May 2004 and April 2006. Consistent net seepage gains were identified in 16 of 20 subreaches analyzed during all seepage runs. The direction of exchange was variable in the remaining four subreaches. Low specific conductance, pH, and calcium concentrations in water from the Withlacoochee River near the headwater area indicated a surface-water system not directly connected to the Upper Floridan aquifer. Downstream from the Dade City station, higher specific conductance, pH, and calcium concentrations in the river water indicated an increasing influence of groundwater, and were similar to groundwater during low-flow conditions. Strontium isotope ratios indicate groundwater originates from shallow parts of the Upper Floridan aquifer in the upper reaches of the river, and from increasingly deeper parts of the aquifer in the downstream direction. Mean annual base-flow estimates also indicate increasing groundwater discharge to the river in the downstream direction. Mean annual base flow estimated using standard hydrograph separation method assumptions ranged from about 4.7 to 5.1 inches per year

Scientific Investigations Report↗
USGS2016

Quantifying seepage using heat as a tracer in selected irrigation canals, Walker River Basin, Nevada, 2012 and 2013

The Walker River is an important source of water for western Nevada. The river provides water for agriculture and recharge to local aquifers used by several communities. Farmers began diverting water from the Walker River in the 1860s to support growing agricultural development. Over time, the reduced inflows into Walker Lake from upstream reservoirs and diversions have resulted in 170 feet of lake level decline and increased dissolved-solids concentrations to levels that threaten aquatic ecosystems, including survival of Lahonton cutthroat trout, a native species listed in the Endangered Species Act. Investigations of the water-budget components in the Walker River Basin have revealed uncertainty in the recharge to aquifers from irrigation canals. To address this need, the U.S. Geological Survey conducted an extensive field study from March 2012 through October 2013 to quantify seepage losses in selected canals in the Smith Valley, Mason Valley, and Walker Lake Valley irrigation areas. The seepage rates estimated for the 2012 and 2013 irrigation seasons in the Smith Valley transect sites (Saroni and Plymouth canals) ranged between 0.01 to 2.5 feet per day (ft/d) (0.01 to 0.68 cubic feet per second per mile [ ft 3 /s-mi ]). From 2012 to 2013, the average number of days the canals had flowing water decreased from 190 to 125 due to drier climate and lack of water available for diversion from the Walker River. The nearly 50-percent reductions in volumetric loss rates between 2012 and 2013 were associated with less than average diversions into canals from the Walker River and reductions in infiltration rates following routine canal maintenance. Models developed for the Saroni canal in 2012 were recalibrated in 2013 to evaluate changes in seepage as a result of siltation. Just prior to the 2012 irrigation season, nearly the entire length of the canal was cleared of vegetation and debris to improve flow conveyance. In 2013, following the first year of maintenance, a 90-percent reduction in seepage was observed at one of the transect sites. The removal of sediment-clogged layers during canal maintenance may have more profound effects on seepage rates beyond what was observed at the transect sites. The seepage rates for the Saroni canal in 2012 ranged from 0.02 to 1.6 ft/d (0.03 to 0.4 ft 3 /s-mi ). The total seepage loss in the Saroni canal for the 2012 and 2013 irrigation seasons was estimated to be 1,100 and 590 acre-feet (acre-ft), respectively. Seepage rates on the Plymouth canal in Smith Valley in 2012 were among the lowest, ranging from 0.01 to 0.2 ft/d (0.01 to 0.1 ft 3 /s-mi ). In 2013, the seepage rate on the Plymouth canal was similar to 2012; however, the volumetric loss was reduced by 50 percent due to the 50-percent reduction in number of canal flow days. Lower rates of seepage on the Plymouth canal for the 2012 and 2013 irrigation seasons were estimated to be 210 and 130 acre-ft, respectively. The seepage rates estimated for the 2012 and 2013 irrigation seasons in the Mason Valley transect sites (Fox, Mickey, and Campbell ditches) ranged from 0.1 to 3.3 ft/d (0.2 to 1.3 ft 3 /s-mi ). The influence of water-table declines on seepage was observed at the Mickey and Campbell ditches. In 2012, the estimated seepage on the Mickey ditch was 1.6 ft/d during a period when the water-table altitude was at or above the canal altitude. Following extensive declines in the water table, the hydraulic gradient increased between the canal and the shallow aquifer, thereby increasing the seepage rates to 3.2 ft/d in 2013. During the period of hydraulic disconnection, seepage rates increased to 9.5 ft/d during intermittent periods of canal flow. For the Mickey ditch, the seepage loss in 2013 was 1.5 times the rate estimated in 2012 despite the canal having 45 days less flow. Similarly, the Campbell ditch seepage loss increased slightly from 660 to 700 acre-ft, a factor of 1.1, with 49 days less flow. The seepage loss for the Fox ditch did not exhibit significant year to year variability. The annual seepage loss estimated for 2012 and 2013 in the Fox ditch was 2,100 and 2,200 acre-ft, respectively. The seepage rates estimated for the 2013 irrigation season in the Walker Lake Valley transect sites (Schurz Lateral Canals 1A and 2A, and Canal 2) ranged from 0.7 to 0.9 ft/d (0.4 to 1.3 ft 3 /s-mi ). In Walker Lake Valley, diversions into Lateral Canals 1A and 2A during the 2013 irrigation season were highly intermittent, a characteristic common of lateral diversions. The annual estimated seepage loss in Walker Lake Valley ranged between 50 and 725 acre-ft among the transect sites.

California, Nevada↗
USGS1981

Kriging analysis of mean annual precipitation, Powder River Basin, Montana and Wyoming

Kriging is a statistical estimation technique for regionalized variables which exhibit an autocorrelation structure. Such structure can be described by a semi-variogram of the observed data. The kriging estimate at any point is a weighted average of the data, where the weights are determined using the semi-variogram and an assumed drift, or lack of drift, in the data. Block, or areal, estimates can also be calculated. The kriging algorithm, based on unbiased and minimum-variance estimates, involves a linear system of equations to calculate the weights. Kriging variances can then be used to give confidence intervals of the resulting estimates. Mean annual precipitation in the Powder River basin, Montana and Wyoming, is an important variable when considering restoration of coal-strip-mining lands of the region. Two kriging analyses involving data at 60 stations were made--one assuming no drift in precipitation, and one a partial quadratic drift simulating orographic effects. Contour maps of estimates of mean annual precipitation were similar for both analyses, as were the corresponding contours of kriging variances. Block estimates of mean annual precipitation were made for two subbasins. Runoff estimates were 1-2 percent of the kriged block estimates. (USGS)

Montana, Wyoming↗
USGS1995

Geology and hydrology of the Edwards Aquifer in the San Antonio area, Texas

The Edwards aquifer, which is the sole source of water for the city of San Antonio, is one of the most permeable and productive carbonate aquifers in the United States. The aquifer is composed of extensively faulted, fractured, and cavernous limestone and dolomite of Early Cretaceous age lying within the Balcones fault zone a series of normal en echelon strike faults that separate the Edwards Plateau from the Gulf Coastal Plain in south Texas. Along segments of some faults, the entire thickness of the aquifer is displaced vertically, and these faults then act as barriers to downdip ground-water flow. The large porosity and exceptional permeability of the unconfined part of the Edwards aquifer result from the dissolution of limestone by circulating ground water and development of a cavernous network along fractures. The large porosity and permeability of the freshwater part of the confined Edwards aquifer result primarily from dedolomitization. The small permeability of the saline-water part of the confined aquifer is caused by the limited interconnection between the pores in the rock matrix and by the lack of substantial dissolution along fractures. The large transmissivity of the Edwards aquifer is indicated by the hundreds of highyielding wells, small hydraulic gradients, and large spring discharges. The determined transmissivity throughout most of the confined freshwater aquifer ranges from 430,000 to 2,200,000 feet squared per day; the determined transmissivity of the unconfined aquifer generally is less than 430,000 feet squared per day. Faulting causes the aquifer to be highly anisotropic, and simulation indicates anisotropy ratios ranging from 0.0:1 to 1:1. The ground-water-flow system of the Edwards aquifer includes several components. These include a catchment area on the Edwards Plateau where the unconfined aquifer receives direct recharge, an area of confining beds crossed by streams draining the Edwards Plateau, a major recharge area within the Balcones fault zone where streams lose flow directly into the unconfined Edwards aquifer, and the confined Edwards aquifer that consists of the freshwater and salinewater zones. Water entering the Edwards aquifer in the Balcones fault zone moves downdip in a generally southeasterly direction into the confined parts of the aquifer. In the confined aquifer, flow is toward the east and northeast under low hydraulic gradients through fractured, highly transmissive limestone and ultimately discharges at large springs and wells. All of the base flow and some of the storm runoff of streams crossing the recharge area infiltrates to the unconfined aquifer. On the basis of streamflow losses, the average annual recharge for 1934-88 was 635,500 acre-feet. Freshwater discharges from the Edwards aquifer primarily from wells, springs, and seeps. Beginning in 1968, annual discharge from the aquifer has consistently exceeded average annual recharge largely because of a doubling of well pumpage. However, total springflow also increased because of greater-than-average recharge during most years since the late 1960's. The total volume of circulating freshwater in the Edwards aquifer is about 45 million acrefeet. Long-term hydrographs at San Antonio indicate no net decline in ground-water levels during 1911-87; thus, there was no net loss of water from storage in the freshwater zone of the Edwards aquifer during that long-term period, assuming the San Antonio hydrograph represents the entire aquifer. However, short-term changes in water levels result largely from the variability of precipitation as indicated by severe declines during the drought of the late 1940's to middle 1950's and by rises to record highs during the abnormally wet years in the 1970's and 1980's. The principal components of the groundwater budget (recharge, springflow, and pumpage) have varied greatly over 55 years (1934-88) of pertinent hydrologic records. Annual recharge varied from about 44,000 to 2,000,000 acre-feet. Annual springflow varied from about 70,000 acrefeet to about 580,000 acre-feet. Pumpage increased from about 100,000 acre-feet annually in the early 1930's to more than 500,000 acre-feet annually during some years in the 1980's. However, the average annual recharge of 635,500 acrefeet is about equal to the sum of the average annual springflow (359,500 acre-feet) and average annual pumpage (273,000 acre-feet), indicating no longterm decrease in ground-water storage because of springflow and pumpage.

Texas↗
USGS1999

Distribution and transport of polychlorinated biphenyls and associated particulates in the Hayton Millpond, south branch Manitowoc River, 1993-95

The distribution and transport of polychlorinated biphenyl (PCB) congeners was determined at two sites on Pine Creek and at the Hayton Millpond on the South Branch of the Manitowoc River in Wisconsin during 1993-95. PCB congener compositions were analyzed in the operationally defined dissolved phase, suspended particulate phase, and surficial bed sediments (0-2 centimeters depth) several times throughout the sampling period. The relative abundances of PCB congeners in the suspended particles and in surficial bed sediments were generally similar to each other and to a known Aroclor mixture (1254). PCB congener composites in the operationally defined dissolved phase were higher in the less chlorinated congeners in keeping with their lower hydrophobicity and higher predicted solubility relative to the more chlorinated congeners. Suspended particle-associated PCB concentrations exhibited two patterns: (1) a cyclical variation in spring and summer associated with algal growth, and (2) episodic increases associated with resuspension of bed sediments during storms. Computed total suspended-solids (TSS) load at the millpond outlet was as high as 920 tons over a 3-month period (June 30-Sept. 30, 1993). Annual TSS loads for the following two years were lower, 610 and 500 tons, respectively. Total PCB concentrations in the water column varied at the millpond outlet, ranging from 34 to 302 nanograms per liter, whereas concentrations upstream on Pine Creek were as high as 563 nanograms per liter. In general, 70 percent of PCB's in the water column were associated with suspended particles. The total congener-summation PCB (SPCB) concentration regression equation incorporated the universal soil loss coefficent to represent erosion of assumedly PCB-free sediment from fields upstream from the millpond. The SPCB load based on the regression relation was 3.4 kilograms during the 3-month high-flow interval (June 30-Sept. 30, 1993). Subsequent annual SPCB loads for the next two water years were 3.5 and 2.3 kilograms, respectively.

Wisconsin↗
USGS2006

Reassessing a troublesome fact of mountain life: Avalanches in Glacier National Park

For the past decade, our U.S. Geological Survey (USGS) research team has rummaged through Glacier National Park’s archives looking for records of snow avalanches. Our searches have paid off. We have found photographs that show snow avalanches blocking progress during the annual spring opening of the famed Going-to-the-Sun Road, ranger logs that describe cabins and telephone lines destroyed by avalanches, and superintendents’ reports that recount avalanche accidents that killed employees or visitors. Recently, we have combined these historical sources with field studies to investigate whether snow avalanches in the park may be more cyclical than random and as much an ecological process as a natural hazard. Our ongoing research in Montana has yielded relevant information for park managers elsewhere who deal with avalanche threats to park infrastructure and for ecologists seeking a better understanding of how mountain ecosystems function. Our research has focused on two transportation corridors: the Going-to-the-Sun Road that bisects the center of the park, and John F. Stevens Canyon, at the park’s southwest corner ( fig. 1 ). The Going-to-the-Sun Road is the park’s most visited attraction; deep snow and avalanches force the road’s closure each winter, and in spring, park crews dig it out using bulldozers and other heavy equipment ( fig. 2 ). Springtime avalanches can bury workers or push equipment off the road and over cliffs ( figs. 3a and 3b ), as happened in 1953, when two workers died. Our research started with a study of how interannual variations in snowfall and avalanches affect the road opening. The initial study helped park managers predict and plan for the road opening in spring and respond to the many topical questions from park visitors and locals. More recent studies have focused on determining the conditions that create springtime avalanches, which are a poorly understood aspect of the avalanche phenomenon.

Wyoming↗
USGS1976

Technical manual for estimating low-flow frequency characteristics of streams in the Susquehanna River basin

This report presents procedures for estimating low-flow frequency characteristics for streams in the Susquehanna River basin. The techniques can be used at ungaged sites as well as sites where insufficient data are available to make a reliable estimate. Streams have been divided intp two types--major and minor. Major streams are the Susquehanna, West Branch Susquehanna, Juniata, and Chemung Rivers. Points on these streams with drainage areas of more than 2,000 mi 2 (5,180 km 2 ) are included in this category. Points on these streams with drainage areas of less than 2,000 mi 2 fall into the minor stream category. Generally minor streams are herein defined as those draining less than 2,000 mi 2 (5,180 km 2 ). Multiple -regression techniques have been used to develop relations for estimating the 1-, 3-, 7-, 30-, and 183-day duration low flows at recurrence intervals of 10, 20, SO and 100 years for annual series data and the 1 - , 3-, 7-, and 30-day duration low flows, at the same recurrence intervals, for six individual months, May through October, inclusive.

Water-Resources Investigations Report↗
USGS1963

Reconnaissance geology and hydrology on the Nett Lake Indian Reservation, Minnesota

The Nett Lake Indian Reservation is in northern Minnesota, about 210 miles north of Minneapolis and St. Paul. The village of Nett Lake (population about 300) is the only community on the reservation. This report is the result of an investigation made to provide a central water source for the village, at the request of the Public Health Service of the U.S. Department of Health, Education, and Welfare. The climate of the area is continental, characterized by cool, subhumid summers and long, severe winters. The average annual precipitation is 24.2 inches. Altitudes in the area range from about 1,190 feet above mean sea level in the Little Fork River channel on the west border of the reservation to about 1,550 feet on top of the Vermilion end moraine, just south of Nett Lake. During the latter part of the Pleistocene Epoch most of the area was inundated by the waters of glacial Lake Agassiz. The area is now drained by the Little Fork River which flows north into the Rainy River, thence into Lake of the Woods, and eventually into Hudson Bay. The geologic units in the Nett Lake area consist of unconsolidated deposits of Recent and Pleistocene age and crystalline rocks of Precambrian age. Most ground water in the Nett Lake area occurs in three different zones: 1) surficial sand and gravel deposits, 2) lake sand underlying compact lake clay, and 3) bedrock fractures. The lake sand underlying the compact clay is the best source of ground water for the village of Nett Lake. It occurs in a small channel immediately west of the village, and it ranges in depth from about 11 to 30 feet below land surface and in thickness from 0 to about 3 feet. The water level is near the surface. A test well yielded 30 gpm (gallons per minute). Two 15 gpm wells would not exceed the long-term yield of the aquifer and would be adequate for the needs of the village.

Open-File Report↗
USGS1996

Water and bed-material quality of selected streams and reservoirs in the Research Triangle area of North Carolina, 1988-94

The Triangle Area Water Supply Monitoring Project was formed by a consortium of local governments and governmental agencies in cooperation with the U.S. Geological Survey to supplement existing data on conventional pollutants, nutrients, and metals to enable eventual determination of long-term trends; to examine spatial differences among water supplies within the region, especially differences between smaller upland sources, large multipurpose reservoirs, and run-of-river supplies; to provide tributary loading inlake data for predictive modeling of Falls of the Neuse and B. Everett Jordan reservoirs; and to establish a database for synthetic organic compounds. Water-quality sampling began in October 1988 at 35 sites located on area run-of-river and reservoir water supplies and their tributaries. Sampling has continued through 1994. Samples were analyzed for major ions, nutrients, trace metals, pesticides, and semivolatile and volatile organic compounds. Monthly concentration data, high-flow concentration data, and data on daily mean streamflow at most stream sites were used to calculate loadings of nitrogen, phosphorus, suspended sediment, and trace metals to reservoirs. Stream and lake sites were assigned to one of five site categories-- (1) rivers, (2) large multipurpose reservoirs, (3) small water-supply reservoirs, (4) streams below urban areas and wastewater-treatment plants, and (5) headwater streams--according to general site characteristics. Concentrations of nitrogen species, phosphorus species, and selected trace metals were compared by site category using nonparametric analysis of variance techniques and qualitatively (trace metals). Wastewater-treatment plant effluents and urban runoff had a significant impact on water quality compared to reservoirs and headwater streams. Streams draining these areas had more mineralized water than streams draining undeveloped areas. Moreover, median nitrogen and nitrite plus nitrate concentrations were significantly greater than all other site categories. Phosphorus was significantly greater than for reservoir sites or headwater streams. Few concentrations of trace metals were greater than the minimum reporting limit, and U.S. Environmental Protection Agency drinking-water standards were rarely exceeded. Detections, when they occurred, were most frequent for sites below urban areas and wastewater-treatment plant effluents. A small number of samples for analysis of acetanilide, triazine, carbamate, and chlorophenoxy acid pesticides indicate that some of these compounds are generally present in area waters in small concentrations. Organochlorine and organophosphorus pesticides are ubiquitous in the study area in very small concentrations. Trihalomethanes were detected at sites below urban areas and wastewater-treatment plants. Otherwise, volatile organic compounds and semivolatile compounds were generally not detected. Suspended-sediment, nitrogen, phosphorus, lead, and zinc loads into Falls Lake, Jordan Lake, University Lake, Cane Creek Reservoir, Little River Reservoir, and Lake Michie were calculated. In general, reservoirs act as traps for suspended sediment and constituents associated with suspended sediments. During 1989-94, annual suspended-sediment load to Falls Lake ranged from 29,500 to 88,200 tons. Because Lake Michie trapped from 83 to 93 percent of the suspended sediment delivered by Flat River, Flat River is a minor contributor of suspended sediment to Falls Lake. Yields of suspended sediment from Little River, Little Lick Creek, and Flat River Basins were between 184 and 223 tons per square mile and appear to have increased increased slightly from yields reported in a study for the period 1970-79. Annual suspended-sediment load to Jordan Lake ranged from 271,000 to 622,000 tons from 1989 through 1994 water years. The Haw River contributed more than 75 percent of the tota load to Jordan Lake. The suspended-sediment yields for Haw River and Northeast Cree

North Carolina↗
USGS2010

Microclimate and limits to photosynthesis in a diverse community of hypolithic cyanobacteria in northern Australia

Hypolithic microbes, primarily cyanobacteria, inhabit the highly specialized microhabitats under translucent rocks in extreme environments. Here we report findings from hypolithic cyanobacteria found under three types of translucent rocks (quartz, prehnite, agate) in a semiarid region of tropical Australia. We investigated the photosynthetic responses of the cyanobacterial communities to light, temperature and moisture in the laboratory, and we measured the microclimatic variables of temperature and soil moisture under rocks in the field over an annual cycle. We also used molecular techniques to explore the diversity of hypolithic cyanobacteria in this community and their phylogenetic relationships within the context of hypolithic cyanobacteria from other continents. Based on the laboratory experiments, photosynthetic activity required a minimum soil moisture of 15% (by mass). Peak photosynthetic activity occurred between approximately 8°C and 42°C, though some photosynthesis occurred between −1°C and 51°C. Maximum photosynthesis rates also occurred at light levels of approximately 150–550 μmol m −2 s −1 . We used the field microclimatic data in conjunction with these measurements of photosynthetic efficiency to estimate the amount of time the hypolithic cyanobacteria could be photosynthetically active in the field. Based on these data, we estimated that conditions were appropriate for photosynthetic activity for approximately 942 h (∼75 days) during the year. The hypolithic cyanobacteria community under quartz, prehnite and agate rocks was quite diverse both within and between rock types. We identified 115 operational taxonomic units (OTUs), with each rock hosting 8–24 OTUs. A third of the cyanobacteria OTUs from northern Australia grouped with Chroococcidiopsis , a genus that has been identified from hypolithic and endolithic communities from the Gobi, Mojave, Atacama and Antarctic deserts. Several OTUs identified from northern Australia have not been reported to be associated with hypolithic communities previously.

Environmental Microbiology↗
USGS1925

Forty-sixth annual report of the Director of the Geological Survey

SIR: The appropriations made directly for the work of the Geological Survey for the fiscal year 1925 included 10 items, amounting to $1,735,423. In addition $110,000, to be disbursed under the direction of the Public Printer, was appropriated for printing the reports of the Survey, and allotments of $10,000 for miscellaneous printing and binding and of $4,944.75 for miscellaneous supplies were made to the Survey from appropriations for the Interior Department. A detailed statement of the amounts appropriated and expended is given at the end of this report. The balance shown is $15,175.31. Cooperation with the States and other public agencies continued as in other years. The value of the mapping and investigative work of the Survey and the necessity of expediting the completion of this physical inventory of the. country's resources is now so widely recognized that 37 States as well as many counties and municipalities shared with the Federal Government in meeting the cost. The total amount thus contributed was $739, 537. 94. Funds aggregating $231,208.90 were placed to the credit of the Geological Survey for services rendered to other Government bureaus and offices. Balances at the end of the year amounted to about $15,000, and the total expenditure, measuring the amount of work accomplished during the year, was $2,690,994.53.

Annual Report↗
USGS2022

Hydrogeology and groundwater quality in the San Agustin Basin, New Mexico, 1975–2019

This report describes the findings of a U.S. Geological Survey study, completed in cooperation with the Bureau of Land Management, focused on better understanding the present-day (1975–2019) hydrogeology and groundwater quality of the San Agustin Basin in west-central New Mexico to support sustainable groundwater resource management. The basin hosts a relatively undeveloped basin-fill and alluvium aquifer system and is topographically divided into east and west subbasins by the McClure Hills. Groundwater chemistry and groundwater elevation data were compiled, collected, and interpreted in the context of groundwater flow and quality. The analyses presented in this report consider groundwater chemistry data collected within the last decade (2010–19) and groundwater elevation data collected from 1975 through 2019 to provide insight into present-day conditions. Groundwater elevations show that groundwater typically moves from the highlands to the lowlands, with a prominent east to west regional trend. Groundwater elevations were lowest in the southwestern portion of the west subbasin, where estimated flow directions suggest underflow through the local highlands into the northern East Fork Gila River watershed, which is further supported by historical groundwater elevation data from the northern East Fork Gila River watershed. Gradual groundwater elevation gradients (about 2 feet per mile) near the east and west subbasin divide suggest that groundwater slowly flows from the east subbasin to the west subbasin. Quantitative analyses of groundwater chemistry data show that groundwater in both subbasins has similar chemical characteristics. A systematic east to west groundwater evolution in water chemistry was not observed despite evidenced subbasin connectivity. The absence of this pattern suggests that groundwater mixing is regionally prevalent, sediment reactivity is low and variable, and (or) recharge conditions are comparable in both subbasins. Groundwater chemistry was generally independent of aquifer type, suggesting that the aquifers are hydrologically well connected. Corrected carbon-14 groundwater age estimates in the basin ranged from 232 to 13,916 years before present with a median of 5,409 years. A wide range of groundwater ages is therefore present in the basin, with waters commonly being thousands of years old, thereby supporting generally slow regional groundwater movement. A component of relatively young groundwater, for which estimated ages could not be accurately computed, is also present in the basin, and it may commonly mix with older waters. The spatial distribution of categorical and quantitative groundwater ages indicates that most recharge likely occurs in the highlands through mountain-block recharge and as focused recharge within arroyos, although evidence of modern (1953 and after) groundwater was minimal at sampled sites. Median annual gradients (groundwater elevation change over time) indicate that most groundwater elevations in the lowlands changed little (−0.2 to 0.2 foot per year) from 1975 through 2019. Groundwater elevations in the highlands varied more annually, which is likely due to recharge from precipitation events. These more variable groundwater elevations in the highlands compared with the lowlands, along with groundwater ages, provide further evidence that most groundwater recharge takes place in the highlands, with minimal recharge in the lowlands. Median groundwater elevation change for all sites was −0.05 foot per year. Temporal consistency of lowland groundwater elevations suggests that regional groundwater dynamics have been more or less stable through time under current climate and development conditions, although median annual gradients indicate that groundwater elevations may have slightly declined on average between 1975 and 2019.

New Mexico↗
USGS2021

Responses of vertebrate wildlife to oil and natural gas development: Patterns and frontiers

Purpose of Review Anthropogenic activities can lead to the loss, fragmentation, and alteration of wildlife habitats. I reviewed the recent literature (2014–2019) focused on the responses of avian, mammalian, and herpetofaunal species to oil and natural gas development, a widespread and still-expanding land use worldwide. My primary goals were to identify any generalities in species’ responses to development and summarize remaining gaps in knowledge. To do so, I evaluated the directionality of a wide variety of responses in relation to taxon, location, development type, development metric, habitat type, and spatiotemporal aspects. Recent Findings Studies ( n = 70) were restricted to the USA and Canada, and taxonomically biased towards birds and mammals. Longer studies, but not those incorporating multiple spatial scales, were more likely to detect significant responses. Negative responses of all types were present in relatively low frequencies across all taxa, locations, development types, and development metrics but were context-dependent. The directionality of responses by the same species often varied across studies or development metrics. Summary The state of knowledge about wildlife responses to oil and natural gas development has developed considerably, though many biases and gaps remain. Studies outside of North America and that focus on herpetofauna are lacking. Tests of mechanistic hypotheses for effects, long-term studies, assessment of response thresholds, and experimental designs that isolate the effects of different stimuli associated with development, remain critical. Moreover, tests of the efficacy of habitat mitigation efforts have been rare. Finally, investigations of the demographic effects of development across the full annual cycle were absent for non-game species and are critical for the estimation of population-level effects.

Current Landscape Ecology Reports↗
USGS2020

Delineation of flood-inundation areas in Grapevine Canyon near Scotty’s Castle, Death Valley National Park, California

On October 18, 2015, a large flood caused considerable damage in Grapevine Canyon near Death Valley Scotty Historic District, in Death Valley National Park, California. Significant channel changes had limited the applicability of previously created flood-inundation maps to current conditions. Predicted flood-inundation maps for Scotty’s Castle were updated using one-dimensional hydraulic models. A digital terrain model was created for the study area using a terrestrial laser scanner for use in the hydraulic models. Estimations of the 4, 2, 1, 0.5, and 0.2-percent annual exceedance probability flood streamflows (previously known as the 25, 50, 100, 250, and 500-year floods) were computed from regional flood regression equations. The estimated flood streamflows were used with the hydraulic models to compute water surface elevations that were mapped on the digital terrain model. The results indicate inundation of the visitor center and park offices occurs by the 4-percent annual exceedance probability flood. Bridge and embankment overtopping occurs by the 2-percent annual exceedance probability flood. Sections of Grapevine Canyon Road and the parking lot are inundated by the 4-percent annual exceedance probability flood and above streamflows. None of the computed streamflows reach Scotty’s Castle main building.

California↗
USGS2022

BFS—A non-linear, state-space model for baseflow separation and prediction

Streamflow in rivers can be separated into a relatively steady component, or baseflow, that represents reliably available surface water and more dynamic components of runoff that typically represent a large fraction of total streamflow. A spatially aggregated numerical time-series model was developed to separate the baseflow component of a streamflow time-series using a state-space framework in which baseflow is a non-linear function of upstream storage, an unmeasured state variable. The state-space framework allows forecasting of baseflow for periods with no rainfall or snowmelt and estimation of residence times in contrast to other hydrograph separation models. The use of a non-linear relation between baseflow and storage maintains model performance over a wide range of time scales but will only provide reliable predictions for periods when the rate of streamflow recession as a fraction of streamflow decreases over time. The baseflow separation model, BFS, is implemented as set of functions in the statistical computing language R. BFS is run using the main function, bf_sep, which reads model input (a time series of streamflow), calculates the baseflow component of streamflow, writes model output to a file, and returns an error to the user to facilitate automated calibration. The function, bf_sep, has six arguments, which a user must enter: a numerical vector with the time series of measured streamflow volume for each time step; a character string, timestep , that has a value of either “daily” or “hourly” indicating the time step; a character string, error_basis, indicating which simulated streamflow components are used for error calculations; a six-element numeric vector, flow , with parameters characterizing streamflow; a six-element vector, basin_char , with parameters characterizing the geometry of stream basin and reservoirs; and a six-element vector, gw_hyd , with hydraulic parameters. The function bf_sep calls a series of other functions to calculate surface and base reservoir storage and fluxes. Calibration of a non-linear model for baseflow recession must confront three issues. First, baseflow is a component of streamflow, so it is always less than or equal to streamflow but there is no independent standard for the baseflow component of streamflow. Second, optimization routines can converge on a set of model parameters that result in relatively steady but minimal baseflow that does not exceed streamflow, Q , but has a limited dynamic range. Third, the power function used to generate non-linear first-order baseflow recession ( dQ/dt )/Q ≠ constant) may only be sensitive to parameters over a limited range of values, which may not be found by optimization routines. To address these issues, BFS calculates error as the mean of weighted differences between measured streamflow and either simulated baseflow or the sum of simulated baseflow and surface flow as a fraction of measured streamflow. The difference for each time step is weighted by an exponential function of the length of recession for each time step ranging from 0 for periods when streamflow increases and approaching 1 for long recessional periods. The weight is set to 1 for any time step when simulated streamflow exceeds measured streamflow. Error calculation incorporates limited precision of streamflow measurements. A four-step calibration process was developed to find a set of viable parameters that maximize the baseflow component within the constraints of the conceptual model (a first-order recession rate that decreases during dry periods). BFS was calibrated at 13,208 U.S. Geological Survey streamgages with available daily streamflow records for at least 300 days from water years 1981 to 2020. The total simulated baseflow component as a fraction of streamflow (BFF) was generally less than the baseflow index (BFI) for 8,368 streamgages where BFF and BFI were available. The median difference was BFF–BFI = 0.11. Large differences were most common in the Interior West where streamflow in many rivers is regulated and is generated predominantly by snowmelt. The baseflow separation model generally allocates less streamflow to baseflow than graphical hydrograph separation in snowmelt rivers. BFS can be used to forecast streamflow during dry periods by using a time series of real-time streamflow with values of Not Available (NA), appended to the time-series to represent missing (future) streamflow values. The forecast skill of BFS was evaluated in terms of difference between simulated baseflow and measured streamflow as a fraction of measured streamflow on the days of the annual maximum recession period at 5,916 of the sites with at least 10 years of record. The median annual error was less than 50 percent at one-half of the sites and generally improved for drier years with longer recession periods.

Scientific Investigations Report↗
USGS1977

Sedimentation in Santa Margarita Lake, San Luis Obispo County, California

The 1975 storage capacity of Santa Margarita Lake in San Luis Obispo County, Calif., was 41,400 acre-feet, a decrease of 3,400 acre-feet since 1941. Usable capacity decreased from 25,800 to 23,000 acre-feet. Long-term sediment yield for the Salinas River basin upstream from the lake was estimated at 1,150 tons per square mile per year. A correlation between the annual water discharge of the Salinas River near Pozo and the annual quantity of sediment deposited in the lake was developed that can be used to stimate future sediment deposition. (Woodard-USGS)

Water-Resources Investigations Report↗
USGS1995

Nutrient loading to Lewisville Lake, north-central Texas, 1984-87

Concentrations of nutrients in the streams of the 1,660-square-mile Lewisville Lake drainage basin have some association with the two types of physiographic regions in the basin prairie regions and cross timbers regions. Total nitrogen and phosphorus concentrations generally are larger in streams draining the prairie regions than in streams draining the cross timbers regions, a characteristic that might be accounted for in part by the fact that prairie regions tend to have more nutrient-rich, less-permeable soils than cross timbers regions. Most of the variability in nutrient loads is associated with variability in discharge. During a low-flow synoptic survey, the largest contributor of total nitrogen and total phosphorus (at the downstream-most site) was Isle du Bois Creek (815 pounds per day of total nitrogen and 146 pounds per day of total phosphorus). During a high-flow synoptic survey, the largest contributor of total nitrogen and total phosphorus (at the downstream-most site) was Elm Fork Trinity River (4,620 pounds per day of total nitrogen and 210 pounds per day of total phosphorus). On the basis of results of stormflow and periodic sampling, the total nitrite plus nitrate nitrogen that entered the reservoir on the average each day during 1986 was 5,640 pounds per day, and during 1987,4,480 pounds per day. During the same period, about one and one-half as much nitrogen in the form of total ammonia plus organic nitrogen entered the reservoir (8,530 pounds per day in 1986 and 7,020 pounds per day in 1987); and about one-fourth as much total phosphorus entered the reservoir during the period (1,310 pounds per day in 1986 and 1,080 pounds per day in 1987). Point sources accounted for small fractions (probably less than 10 percent) of the total nutrient load from Clear Creek, Little Elm Creek, Hickory Creek, and Elm Fork Trinity River. Most of the point-source load to Lewisville Lake could originate at a few sewage-treatment plants discharging to ungaged streams close to the reservoir. The estimated long-term (1974-89 water years) average annual total nitrogen load (excluding loads from sewage-treatment plants in ungaged areas) is 11,800 pounds per day. The estimated long-term (1974 89 water years) average annual total phosphorus load (excluding loads from sewage-treatment plants in ungaged areas) is 1,100 pounds per day.

Texas↗