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At least 307 records · Page 17Linked to original sources
USGS2012

Hydrologic conditions, groundwater quality, and analysis of sink hole formation in the Albany area of Dougherty County, Georgia, 2009

The U.S. Geological Survey, in cooperation with the Albany Water, Gas, and Light Commission has conducted water resources investigations and monitored groundwater conditions and availability in the Albany, Georgia, area since 1977. This report presents an overview of hydrologic conditions, water quality, and groundwater studies in the Albany area of Dougherty County, Georgia, during 2009. Historical data also are presented for comparison with 2009 data. During 2009, groundwater-level data were collected in 29 wells in the Albany area to monitor water-level trends in the surficial, Upper Floridan, Claiborne, Clayton, and Providence aquifers. Groundwater-level data from 21 of the 29 wells indicated an increasing trend during 2008–09. Five wells show no trend due to lack of data and three wells have decreasing trends. Period-of-record water levels (period of record ranged between 1957–2009 and 2003–2009) declined slightly in 10 wells and increased slightly in 4 wells tapping the Upper Floridan aquifer; declined in 1 well and increased in 2 wells tapping the Claiborne aquifer; declined in 4 wells and increased in 2 wells tapping the Clayton aquifer; and increased in 1 well tapping the Providence aquifer. Analyses of groundwater samples collected during 2009 from 12 wells in the Upper Floridan aquifer in the vicinity of a well field located southwest of Albany indicate that overall concentrations of nitrate plus nitrite as nitrogen increased slightly from 2008 in 8 wells. A maximum concentration of 12.9 milligrams per liter was found in a groundwater sample from a well located upgradient from the well field. The distinct difference in chemical constituents of water samples collected from the Flint River and samples collected from wells located in the well-field area southwest of Albany indicates that little water exchange occurs between the Upper Floridan aquifer and Flint River where the river flows adjacent to, but downgradient of, the well field. Water-quality data collected during 2008 from two municipal wells located in northern Albany and downgradient from a hazardous waste site indicate low-level concentrations of pesticides in one of the wells; however, no pesticides were detected in samples collected during 2009. Detailed geologic cross sections were used to create a three-dimensional, hydrogeologic diagram of the well field southwest of Albany in order to examine the occurrence of subsurface features conducive to sinkhole formation. Monitored groundwater-level data were used to assess the possible relations between sinkhole formation, precipitation, and water levels in the Upper Floridan aquifer. Although the water levels in well 12L382 oscillated above and below the top of the aquifer on a regular basis between 2007 and 2009, sinkhole development did not appear to correlate directly with either well-field pumping or water levels in the Upper Floridan aquifer. Specifically, two sinkholes formed in each of the years 2003 and 2005 when water levels were almost 20 feet above the top of the aquifer during most of the year. Water-level and sinkhole-formation data continue to be collected to allow further study and analysis.

Georgia↗
USGS2006

Evaluating uncertainty in predicting spatially variable representative elementary scales in fractured aquifers, with application to Turkey Creek Basin, Colorado

Computational limitations and sparse field data often mandate use of continuum representation for modeling hydrologic processes in large‐scale fractured aquifers. Selecting appropriate element size is of primary importance because continuum approximation is not valid for all scales. The traditional approach is to select elements by identifying a single representative elementary scale (RES) for the region of interest. Recent advances indicate RES may be spatially variable, prompting unanswered questions regarding the ability of sparse data to spatially resolve continuum equivalents in fractured aquifers. We address this uncertainty of estimating RES using two techniques. In one technique we employ data‐conditioned realizations generated by sequential Gaussian simulation. For the other we develop a new approach using conditioned random walks and nonparametric bootstrapping (CRWN). We evaluate the effectiveness of each method under three fracture densities, three data sets, and two groups of RES analysis parameters. In sum, 18 separate RES analyses are evaluated, which indicate RES magnitudes may be reasonably bounded using uncertainty analysis, even for limited data sets and complex fracture structure. In addition, we conduct a field study to estimate RES magnitudes and resulting uncertainty for Turkey Creek Basin, a crystalline fractured rock aquifer located 30 km southwest of Denver, Colorado. Analyses indicate RES does not correlate to rock type or local relief in several instances but is generally lower within incised creek valleys and higher along mountain fronts. Results of this study suggest that (1) CRWN is an effective and computationally efficient method to estimate uncertainty, (2) RES predictions are well constrained using uncertainty analysis, and (3) for aquifers such as Turkey Creek Basin, spatial variability of RES is significant and complex.

Water Resources Research↗
USGS2016

Climate-induced glacier and snow loss imperils alpine stream insects

Climate warming is causing rapid loss of glaciers and snowpack in mountainous regions worldwide. These changes are predicted to negatively impact the habitats of many range-restricted species, particularly endemic, mountaintop species dependent on the unique thermal and hydrologic conditions found only in glacier-fed and snowmelt-driven alpine streams. Though progress has been made, existing understanding of the status, distribution, and ecology of alpine aquatic species, particularly in North America, is lacking, thereby hindering conservation and management programs. Two aquatic insects – the meltwater stonefly Lednia tumana and the glacier stonefly Zapada glacier – were recently proposed for listing under the U.S. Endangered Species Act due to climate-change-induced habitat loss. Using a large dataset (272 streams, 482 total sites) with high-resolution climate and habitat information, we describe the distribution, status, and key environmental features that limit L. tumana and Z. glacier across the northern Rocky Mountains. Lednia tumana was detected in 113 streams (175 sites) within Glacier National Park (GNP) and surrounding areas. The probability of L. tumana occurrence increased with cold stream temperatures and close proximity to glaciers and permanent snowfields. Similarly, densities of L. tumana declined with increasing distance from stream source. Zapada glacier was only detected in 10 streams (20 sites), six in GNP and four in mountain ranges up to ~600 km southwest. Our results show that both L. tumana and Z. glacier inhabit an extremely narrow distribution, restricted to short sections of cold, alpine streams often below glaciers predicted to disappear over the next two decades. Climate warming-induced glacier and snow loss clearly imperils the persistence of L. tumana and Z. glacier throughout their ranges, highlighting the role of mountaintop aquatic invertebrates as sentinels of climate change in mid-latitude regions.

Global Change Biology↗
USGS2009

Water Withdrawals, Use, and Trends in Florida, 2005

In 2005, the total amount of water withdrawals in Florida was estimated at 18,359 million gallons per day (Mgal/d). Saline water accounted for 11,486 Mgal/d (63 percent), and freshwater accounted for 6,873 Mgal/d (37 percent). Groundwater accounted for 4,247 Mgal/d (62 percent) of freshwater withdrawals, and surface water accounted for the remaining 2,626 Mgal/d (38 percent). Surface water accounted for nearly all (99.9 percent) saline-water withdrawals. An additional 660 Mgal/d of reclaimed wastewater was used in Florida during 2005. The largest amount of freshwater was withdrawn from Palm Beach County, and the largest amount of saline water was withdrawn from Pasco County. Fresh groundwater provided drinking water (public supplied and self-supplied) for 16.19 million people (90 percent of Florida's population), and fresh surface water provided drinking water for 1.73 million people (10 percent). The majority of groundwater withdrawals (nearly 60 percent) in 2005 was obtained from the Floridan aquifer system which is present throughout the entire State. The majority of fresh surface-water withdrawals (59 percent) came from the southern Florida hydrologic unit subregion and is associated with Lake Okeechobee and the canals in the Everglades Agricultural Area of Glades, Hendry, and Palm Beach Counties, as well as the Caloosahatchee River and its tributaries in the agricultural areas of Collier, Glades, Hendry, and Lee Counties. Overall, agricultural irrigation accounted for 40 percent of the total freshwater withdrawals (ground and surface), followed by public supply with 37 percent. Public supply accounted for 52 percent of groundwater withdrawals, followed by agricultural self-supplied (31 percent), ommercial-industrial-mining self-supplied (8.5 percent), recreational irrigation and domestic self-supplied (4 percent each), and power generation (0.5 percent). Agricultural self-supplied accounted for 56 percent of fresh surface-water withdrawals, followed by power generation (20.5 percent), public supply (13 percent), recreational irrigation (6 percent), and commercial-industrial self-supplied (4.5 percent). Power generation accounted for nearly all (99.9 percent) saline-water withdrawals. Of the 17.92 million people who resided in Florida during 2005, 41 percent (7.36 million people) resided in the South Florida Water Management District (SFWMD), followed by the St. Johns River Water Management District (SJRWMD) and the Southwest Florida Water Management District (SWFWMD) with 25 percent each (4.46 and 4.44 million people, respectively), the Northwest Florida Water Management District (NWFWMD) with 7.5 percent (1.34 million people), and the Suwannee River Water Management District (SRWMD) with 1.5 percent (0.32 million people). The largest amount of freshwater withdrawals was from the SFWMD, which was one-half (50 percent) of the State's total freshwater withdrawals, followed by the SJRWMD (19 percent), SWFWMD (16 percent), NWFWMD (10 percent), and SRWMD (5 percent). Between 1950 and 2005, the population of Florida increased by 15.15 million (550 percent), and the total water withdrawals (fresh and saline) increased 15,700 Mgal/d (600 percent). More recently, total withdrawals decreased 1,790 Mgal/d (9 percent) between 2000 and 2005, but the total population increased by 1.94 million (12 percent). Between 1990 and 2005, saline-water withdrawals increased 1,120 Mgal/d (11 percent), whereas between 2000 and 2005, saline-water withdrawals decreased 470 Mgal/d (4 percent). Between 1990 and 2005, freshwater withdrawals decreased 710 Mgal/d (9 percent), whereas between 2000 and 2005, freshwater withdrawals decreased 1,320 Mgal/d (16 percent). The use of highly mineralized groundwater as a source of supply, primarily for public supply, also has increased in Florida. This water, referred as nonpotable water, increased from just less than 2 Mgal/d in 1970, to 142 Mgal/d in 2005. Nonpotable water is treated to meet drin

Scientific Investigations Report↗
USGS2009

Patterns of Tamarix water use during a record drought

During a record drought (2006) in southwest Kansas, USA, we assessed groundwater dynamics in a shallow, unconfined aquifer, along with plant water sources and physiological responses of the invasive riparian shrub Tamarix ramosissima. In early May, diel water table fluctuations indicated evapotranspirative consumption of groundwater by vegetation. During the summer drought, the water table elevation dropped past the lowest position previously recorded. Concurrent with this drop, water table fluctuations abruptly diminished at all wells at which they had previously been observed despite increasing evapotranspirative demand. Following reductions in groundwater fluctuations, volumetric water content declined corresponding to the well-specific depths of the capillary fringe in early May, suggesting a switch from primary dependence on groundwater to vadose-zone water. In at least one well, the fluctuations appear to re-intensify in August, suggesting increased groundwater uptake by Tamarix or other non-senesced species from a deeper water table later in the growing season. Our data suggest that Tamarix can rapidly shift water sources in response to declines in the water table. The use of multiple water sources by Tamarix minimized leaf-level water stress during drought periods. This study illustrates the importance of the previous hydrologic conditions experienced by site vegetation for controlling root establishment at depth and demonstrates the utility of data from high-frequency hydrologic monitoring in the interpretation of plant water sources using isotopic methods. ?? Springer-Verlag 2009.

Oecologia↗
USGS2014

Water withdrawals, use, and trends in Florida, 2010

In 2010, the total amount of water withdrawn in Florida was estimated to be 14,988 million gallons per day (Mgal/d). Saline water accounted for 8,589 Mgal/d (57 percent) and freshwater accounted for 6,399 Mgal/d (43 percent). Groundwater accounted for 4,166 Mgal/d (65 percent) of freshwater withdrawals, and surface water accounted for the remaining 2,233 Mgal/d (35 percent). Surface water accounted for nearly all (99.9 percent) saline-water withdrawals. An additional 659 Mgal/d of reclaimed wastewater was used in Florida during 2010. Freshwater withdrawals were greatest in Palm Beach County (707 Mgal/d), and saline-water withdrawals were greatest in Hillsborough County (1,715 Mgal/d). Fresh groundwater provided drinking water (public supplied and self-supplied) for 17.33 million people (92 percent of Florida’s population), and fresh surface water provided drinking water for 1.47 million people (8 percent). The statewide public-supply gross per capita use for 2010 was 134 gallons per day, whereas the statewide public-supply domestic per capita use was 85 gallons per day. The majority of groundwater withdrawals (almost 62 percent) in 2010 were obtained from the Floridan aquifer system, which is present throughout most of the State. The majority of fresh surface-water withdrawals (56 percent) came from the southern Florida hydrologic unit subregion and is associated with Lake Okeechobee and the canals in the Everglades Agricultural Area of Glades, Hendry, and Palm Beach Counties, as well as the Caloosahatchee River and its tributaries in the agricultural areas of Collier, Glades, Hendry, and Lee Counties. Overall, agricultural irrigation accounted for 40 percent of the total freshwater withdrawals (ground and surface), followed by public supply with 35 percent. Public supply accounted for 48 percent of groundwater withdrawals, followed by agricultural self-supplied (34 percent), commercial-industrial-mining self-supplied (7 percent), recreational-landscape irrigation and domestic self-supplied (5 percent each), and power generation (less than 1 percent). Agricultural self-supplied accounted for 51 percent of fresh surface-water withdrawals, followed by power generation (25 percent), public supply (11 percent), recreational-landscape irrigation (9 percent), and commercial-industrial-mining self-supplied (4 percent). Power generation accounted for nearly all (99.8 percent) saline-water withdrawals. Of the 18.80 million people who resided in Florida during 2010, 41 percent (7.68 million people) resided in the South Florida Water Management District (SFWMD), 25 percent each resided in the Southwest Florida Water Management District (SWFWMD) and the St. Johns River Water Management District (SJRWMD) (4.73 and 4.70 million people, respectively), 7 percent (1.36 million people) resided in the Northwest Florida Water Management District (NWFWMD), and 2 percent (0.33 million people) resided in the Suwannee River Water Management District (SRWMD). The largest percentage of freshwater withdrawals was from the SFWMD (47 percent), followed by the SJRWMD (21 percent), SWFWMD (18 percent), NWFWMD (9 percent), and SRWMD (5 percent). Between 1950 and 2010, the population of Florida increased by 16.03 million (580 percent), and the total water withdrawals (fresh and saline) increased by 12,334 Mgal/d (465 percent). More recently, total freshwater withdrawals decreased by more than 1,792 Mgal/d (22 percent) between 2000 and 2010, while the population increased by 2.82 million (18 percent), and total freshwater withdrawals decreased by more than 474 Mgal/d (7 percent) between 2005 and 2010, while the population increased by 0.88 million (8 percent). The recent trend of decreases in freshwater withdrawals is a result of increased rainfall during this period, the development and use of alternative water sources, water conservation efforts, more conservative regulations and mandates, changes in economic conditions, and losses of irrigated lands. Fresh-water withdrawals for public supply, agricultural self-supplied use, and commercial-industrial-mining self-supplied use all decreased between 2000 and 2010 and between 2005 and 2010, whereas freshwater withdrawals for domestic self-supplied use, recreational-landscape irrigation use, and power generation use either remained the same or changed slightly during the decade. The use of highly mineralized groundwater (referred to as nonpotable water) as a source of drinking water has increased in Florida. Nonpotable water use for public supply has increased from nearly 2 Mgal/d in 1970 to about 165 Mgal/d in 2010. Nonpotable water is either blended or treated to meet drinking-water standards and is mostly used along the east and west coasts of central and southern Florida. The use of reclaimed wastewater increased from about 206 Mgal/d in 1986 to nearly 659 Mgal/d in 2010. More than three-quarters (79 percent) of reclaimed wastewater in 2010 was used to supplement potable-quality water withdrawals for urban irrigation, agricultural irrigation, and industrial use.

Florida↗
USGS1999

Field trip guide to selected studies of the Southwest Mineral and Environmental Investigations Project in southeastern Arizona

The Southwest Mineral and Environmental Investigations Project is designed to address issues raised by rapid urban development in the basins of the southwestern U.S. These issues require objective geoscientific data that can be used by land managers and stakeholders to develop informed land and water use strategies. The project integrates new and existing geologic, geophysical, and geochemical data, and imagery to provide three-dimensional visualizations of the basins of southeastern Arizona. Emphasis is on developing better knowledge of the aquifer systems of both the basins and the ranges, on acquiring background and baseline information, and on determining the distribution of metals related to mineralization and the fate of these metals in surface and subsurface environments. The products of the project will be used in resolving issues of water quality and quantity, in understanding environmental impacts such as riparian ecosystem maintenace, and in evaluating mineral resources beneath and within the basins. The field trip highlights three topics and areas (figs. 1 and 2): (1) geology and geophysics of the upper San Pedro and upper Santa Cruz basins (M.E. Gettings, M. W. Bultman, and B.B. Houser), (2) geology, geophysics, and mineral resource potential of the San Rafael basin (M.W. Bultman), and (3) hydrology and aqueous geochemistry of the Red Mountain and Sonoita Creek drainage system (Floyd Gray). The trip guide, which begins and ends in Tucson, Arizona, also includes commentary on the cultural and mining history of the area.

Arizona↗
USGS2014

Bedrock geologic and structural map through the western Candor Colles region of Mars

The Candor Colles are a population of low, conical hills along the southeast flank of Ceti Mensa, in west Candor Chasma, within the Valles Marineris system of Mars (fig. 1). Ceti Mensa and the adjacent Candor Mensa are mounds of layered sedimentary deposits and are the most prominent landforms within west Candor Chasma. Prior to the arrival of the Mars Reconnaissance Orbiter (MRO) in orbit around Mars in 2006 (Zurek and Smrekar, 2007), geologic maps of the area utilized the relatively low resolution Viking Orbiter photomosaics (20–150 m/pixel). Geologic maps covering west Candor Chasma were created at scales of 1:15,000,000 for the western equatorial region of Mars (Scott and Tanaka, 1986), 1:2,000,000 for the Valles Marineris region (Witbeck and others, 1991), and 1:500,000 for the far eastern part of west Candor Chasma (Mars Transverse Mercator quadrangle–05072; Lucchitta, 1999). Previous structural mapping in west Candor Chasma at scales of less than 1:24,000 (Okubo and others, 2008; Okubo, 2010) employed digital terrain models (DTMs), with 1-m post spacings, derived from stereo MRO High Resolution Imaging Science Experiment (HiRISE) imagery (McEwen and others, 2010) and focused on examining the relative timing between deposition of the youngest unit of the layered deposits in this area (unit Avme of Witbeck and others, 1991) relative to regional faulting related to chasma formation. These previous mapping efforts on the southwest flank of Ceti Mensa demonstrated that unit Avme is not deformed by faults attributed to formation of the chasma. Studies of other layered deposits (primarily unit Hvl, but also including units Avme, Avsl, Avsd, and Avfs; Witbeck and others, 1991) exposed along the southeast flank of Ceti Mensa using a High-Resolution Stereo Camera (HRSC) digital terrain model (DTM) (50 m/pixel) refined the local stratigraphy and revealed evidence for syntectonic deposition of these deposits (Fueten and others, 2006, 2008; Jaumann and others, 2007; Birnie and others, 2012). Layered deposits such as those that constitute Ceti Mensa are widespread throughout the interior regions of Valles Marineris (Witbeck and others, 1991). These sedimentary deposits have been variously interpreted as eolian sediments (Nedell and others, 1987), hyaloclastic debris (Chapman and Tanaka, 2001; Komatsu and others, 2004), lacustrine or fluvial sediment (Dromart and others, 2007; Mangold and others, 2008; Metz and others, 2009), pyroclastic deposits (Hynek and others, 2003), evaporites (Mangold and others, 2008; Andrews-Hanna and others, 2010), or various combinations thereof. Recent analysis of data from the MRO Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) shows that these sediments consist primarily of hydrated sulfates (Murchie and others, 2009a,b). Further, hydrologic modeling indicates that spring-fed lakes likely occurred within the chasma (Andrews-Hanna and others, 2010). These recent findings point to a scenario in which the layered deposits accumulated as sequences of evaporites precipitating in hypersaline lakes, with contemporaneous trapping of eolian dust and sand, diagenesis, and iron-cycling, interspersed with periods of eolian and fluvial erosion (Murchie and others, 2009a). Water vapor released from these lakes may have also driven localized precipitation of snow and accumulation of layered deposits on the adjacent plateaus (Kite and others, 2011a,b). This scenario is in contrast to recent alternative interpretations that the layered deposits formed within the chasma through weathering of dust-rich ice deposits (Niles and Michalski, 2009; Michalski and Niles, 2012). The structure and geology of the layered deposits in the Candor Colles region corresponding to units Avfs, Avme, and Hvl of Witbeck and others (1991) are reevaluated in this 1:18,000-scale map. The objectives herein are to gather high-resolution structural measurements to (1) refine the previous unit boundaries in this area established by Witbeck and others (1991), (2) revise the local stratigraphy where necessary, (3) characterize bed forms to help constrain depositional processes, and (4) determine the styles and extent of deformation to better inform reconstructions of the local post-depositional geologic history.

Scientific Investigations Map↗
USGS1975

Hydrology of the Lake Wingra basin, Dane County, Wisconsin

A water budget was prepared to identify the components of the hydrologic system in the Lake Wingra basin. The Lake Wingra basin, which includes a small eutrophic lake within the city of Madison, Wis., is partly a protected area and partly an urbanized area. Measured and estimated inflow and outflow to and from the lake in 1 year (June 1972 to May 1973) was about 4.5 metres (15 feet)—approximately twice the volume of the lake. Inflow to the lake is about 25 percent from direct precipitation on the lake surface, and the rest from nearly equal amounts of surface runoff and ground-water inflow. Outflow from the lake is about 10 percent ground-water outflow, 15 percent evaporation from the lake surface, and 75 percent discharge at the surface outlet. Increased withdrawal of water from municipal and industrial wells in Madison has slowed the rate of flow through the lake. The calculated 1972 water budget for the lake showed gains of about 3,560 millimetres (140 inches) and losses of about 3,500 millimetres (138 inches). A discrepancy of about 60 millimetres (2 inches) probably was caused in part by uncertainties in ground-water inflow and outflow. Effects of evapotranspiration and ground-water inflow in the marsh area southwest of the lake also probably contribute to the discrepancy.

Wisconsin↗
USGS1953

Water resources of the Minneapolis-St. Paul area, Minnesota

The water supply of the Minneapolis-St. Paul area is adequate to satisfy present requirements and requirements for many years to come if the area continues to develop at about the present rate. The flow of -the Mississippi River at the Twin Cities is more than sufficient to meet the demands of the water-supply systems of Minneapolis and St. Paul. The lowest momentary flow during the period 1931-51 was more than twice the present combined maximum demand of Minneapolis and St. Paul. The lake storage of the St. Paul system combined with possible regulations by the Mississippi River headwater reservoir system, in case of an emergency, provides a reserve supply ample to meet a greatly expanded demand. The lowest average daily flow of the Mississippi River at the intakes of the Minneapolis and St. Paul water supply was 389 mgd (602 cfs), The flow at the water supply intakes has been less than 452 mgd (700 cfs) for not more than 6 consecutive days. Except for the Mississippi River, the streams in the Twin Cities area have not been extensively developed for water supply. The only known use of them for water supply is for the steam-electric. generating plant on the Minnesota River at Savage. Thus, the St. Croix River, within 12 miles on the east, the Minnesota River entering the Twin Cities from the southwest, the Vermilion within 12 miles on the south, and the Crow River within 25 miles on the west offer untapped supplies for industrial and municipal uses. Many water-bearing formations occur in the area. A blanket of glacial deposits, as much as 400 feet thick, covers the area. Small domestic ground-water supplies can be developed practically everywhere in the glacial deposits, and larger industrial supplies can be obtained by exploring and testing. Below the glacial materials is a thick series of rock formations including several prolific sandstone aquifers. The formations dip toward the center of the area forming an artesian basin. The estimated average daily withdrawal of ground water from all aquifers in the area is about 90 mgd. Practically all the communities that are not supplied by the Minneapolis or St. Paul water-supply systems obtain their water from wells. Where many large-capacity wells have been concentrated in relatively small areas, there has been a great lowering of artesian pressures. However, there are large areas, distant from the centers of concentrated pumping, which are favorable for the development of additional ground water. With an adequate program of exploration and testing to determine precisely the geologic and hydrologic characteristics of the waterbearing formations, it is likely that large additional supplies of ground water can be developed for municipal and industrial uses. Both Minneapolis and St. Paul obtain their municipal water supplies from the Mississippi River above the TwinCities and are thus assured of a large supply that is not subject to contamination by industrial wastes and sewage effluents, Treatment at municipal plants for both cities provides water for diversified industrial use and for domestic use that meets U. S. Public Health Service drinking water standards., The treated water is remarkably uniform in chemical composition throughout the year and is virtually free of all color, iron, manganese, and turbidity. Currently, (1952). the two supplies are softened to about 75 ppm (as CaC03), which is an average reduction of about 55 percent in hardness of river water. The dissolvedsolids content of the treated water for St. Paul currently (1952) averages about 100 ppm; the dissolved-solids content of the Minneapolis water is slightly higher. As a matter of further interest to industrial consumers, temperatures of the untreated river water, which is only slightly altered at the Minneapolis treatment plant, averages less than 60 F for about 8 months of the year and is less than 40 F for 4 winter months. The Mississippi River as it enters the Twin Cities is moderately mineralized, averaging 241 ppm dissolved solids and 179 ppm hardness during the period 1940-49, Average turbidity is very low and silica is moderately low, but the quantities of iron and color in solution are relatively high. Color increases markedly during the period March to July in response to an increase in streamflow. The average chemical composition of the water has remained virtually unchanged except for seasonal variations since 1907. Data collected by the Minneapolis-St. Paul Sanitary District have shown improved sanitary conditions of the river at the Twin Cities lock and dam since the sewage plant went into operation in 1939. The Minnesota River is more than twice as mineralized and hard as the Mississippi River, and it exerts a noticeable effect on the chemical and sanitary quality of the Mississippi River at St. Paul. Other principal tributary streams to the Mississippi River, including Crow River, Vermilion River, and Bassett Creek, were sampled during the 1952 flood season, at which time they were of the calcium-bicarbonate type, more dilute, and of lower hardness than the Minnesota River. Lake waters in the Twin Cities area generally are less mineralized than those of the streams. Waters from the drift deposits and bedrock formations overlying the Hinckley sandstone are hard and calcareous and generally contain troublesome quantities of iron. Regular treatment is required of some public-supply wells for removal of iron encrustations. Water fr.om these sources generally exceeds 300 ppm hardness, but in some places the St. Peter sandstone and St. Lawrence formation yield water of better quality. The Hinckley sandstone yields the best quality ground-water because of its comparatively lower hardness and uniform temperature (about 52 F). However, the average hardness of the treated municipal supplies of St. Paul and Minneapolis is considerably less than water from the Hinckley.

Minnesota↗
USGS2010

Estimation of selected streamflow statistics for a network of low-flow partial-record stations in areas affected by Base Realignment and Closure (BRAC) in Maryland

The U.S. Geological Survey, in cooperation with the Maryland Department of the Environment, operated a network of 20 low-flow partial-record stations during 2008 in a region that extends from southwest of Baltimore to the northeastern corner of Maryland to obtain estimates of selected streamflow statistics at the station locations. The study area is expected to face a substantial influx of new residents and businesses as a result of military and civilian personnel transfers associated with the Federal Base Realignment and Closure Act of 2005. The estimated streamflow statistics, which include monthly 85-percent duration flows, the 10-year recurrence-interval minimum base flow, and the 7-day, 10-year low flow, are needed to provide a better understanding of the availability of water resources in the area to be affected by base-realignment activities. Streamflow measurements collected for this study at the low-flow partial-record stations and measurements collected previously for 8 of the 20 stations were related to concurrent daily flows at nearby index streamgages to estimate the streamflow statistics. Three methods were used to estimate the streamflow statistics and two methods were used to select the index streamgages. Of the three methods used to estimate the streamflow statistics, two of them--the Moments and MOVE1 methods--rely on correlating the streamflow measurements at the low-flow partial-record stations with concurrent streamflows at nearby, hydrologically similar index streamgages to determine the estimates. These methods, recommended for use by the U.S. Geological Survey, generally require about 10 streamflow measurements at the low-flow partial-record station. The third method transfers the streamflow statistics from the index streamgage to the partial-record station based on the average of the ratios of the measured streamflows at the partial-record station to the concurrent streamflows at the index streamgage. This method can be used with as few as one pair of streamflow measurements made on a single streamflow recession at the low-flow partial-record station, although additional pairs of measurements will increase the accuracy of the estimates. Errors associated with the two correlation methods generally were lower than the errors associated with the flow-ratio method, but the advantages of the flow-ratio method are that it can produce reasonably accurate estimates from streamflow measurements much faster and at lower cost than estimates obtained using the correlation methods. The two index-streamgage selection methods were (1) selection based on the highest correlation coefficient between the low-flow partial-record station and the index streamgages, and (2) selection based on Euclidean distance, where the Euclidean distance was computed as a function of geographic proximity and the basin characteristics: drainage area, percentage of forested area, percentage of impervious area, and the base-flow recession time constant, t. Method 1 generally selected index streamgages that were significantly closer to the low-flow partial-record stations than method 2. The errors associated with the estimated streamflow statistics generally were lower for method 1 than for method 2, but the differences were not statistically significant. The flow-ratio method for estimating streamflow statistics at low-flow partial-record stations was shown to be independent from the two correlation-based estimation methods. As a result, final estimates were determined for eight low-flow partial-record stations by weighting estimates from the flow-ratio method with estimates from one of the two correlation methods according to the respective variances of the estimates. Average standard errors of estimate for the final estimates ranged from 90.0 to 7.0 percent, with an average value of 26.5 percent. Average standard errors of estimate for the weighted estimates were, on average, 4.3 percent less than the best average standard errors of estima

Scientific Investigations Report↗
USGS2007

Investigation of wind and water level for the Giacomini Wetland Restoration Project, Point Reyes National Seashore

Point Reyes National Seashore (PRNS), comprising unique elements of geological, biological, and historical interest, is located on the central California coast approximately 60 km northwest of San Francisco. The National Seashore contains nearly 130 km of exposed and protected shorelines, spectacular coastal cliffs and headlands, lagoons, open grasslands, bushy hillsides, and forested ridges. Approximately 30 km of the shoreline are coastal-dune habitat that supports 11 federally listed species, including the threatened western snowy plover and the endangered plants Tidestrom's lupine ( Lupinus tidestromii ) and beach layia ( Layia carnosa ). The San Andreas Fault, a right-lateral strike-slip fault, trends northwest along the northeastern side of the park. Tomales Bay, which is straight, long, narrow, and shallow, runs along the northeastern boundary of PRNS. The Bay, which fills the northwestern end of a rift valley at the intersection of the San Andreas Fault with the coastline, is approximately 20 km long, 2 km wide, and 6 m deep with mountainous terrain to the southwest and rolling hills to the northeast. Tomales Bay is one of the cleanest estuaries on the West Coast. In winter, approximately 17,000 to 20,000 shorebirds inhabit Tomales Bay and Bodega Bay, which lies directly to the north. At the head of Tomales Bay, the Giacomini Ranch comprises 563 acres of pastureland currently being used for grazing dairy cattle. After more than 50 years of operation as a dairy, the National Park Service acquired the Giacomini property with the intention to restore most of it and the nearby Olema Marsh to tidal wetland. Restoration will add approximately 4% to the existing coastal wetlands in California. The project will return the headwaters of Tomales Bay and two major stream intersections to an intertidal marsh environment, enhancing habitat for both wildlife and fish populations and contributing to the long-term health of Tomales Bay. Prior to the establishment of the ranch, the area was primarily salt marsh that formed as the delta of Lagunitas Creek expanded into Tomales Bay. In converting the salt marsh to dairy land, levees and tide gates were constructed to prevent tidal incursion and stream flooding. Those levees have significantly altered the patterns of estuarine circulation and sediment deposition. To restore natural hydrologic processes within the area and to promote the return of ecological functions and processes, the levees will have to be breached or removed. Developing a successful restoration strategy requires knowledge of elevations within the pastureland and the range of water depths that can be expected from tidal, river, and wind action. In support of the restoration program, the USGS provides technical assistance to PRNS in the form of a scientific study focusing on understanding the physical processes that could affect the Giacomini wetland restoration. The study will yield scientific products that NPS resource managers can use in designing and implementing the restoration project. Research elements include: - Develop a Geodetic Control Network (GCN) throughout PRNS that meets the standards specified National Geodetic Survey data base (the NGS "Bluebook"). The grid will allow this and future studies to be conducted to a precision commensurate with the expressed goals of PRNS. The survey will consist of three steps: (1) verify existing GPS control monuments in the area; (2) tie control monuments in the study areas to the GPS control monuments; and (3) establish NAVD88 elevations using a digital electronic level. - Conduct a detailed survey of the Giacomini site to produce an accurate topographic map of the property. The site survey can be coupled with on-site water-level measurements to produce an empirical flooding model. - Measure water level and wind regime at the Giacomini site. The water-level range is critical to determining the wetland types based on the elevation of the dairy land. Water level at Sacramento Landing, in central Tomales Bay, will also be measured for comparison. As of November 2005, we have created a GCN, produced a detailed topographic map of the Giacomini site, and collected approximately three years of water-level and wind data at the Giacomini site and over one year of usable water-level data at the Sacramento Landing pier.

California↗
USGS2022

On the role of climate in monthly baseflow changes across the continental United States

Baseflow is the portion of streamflow that comes from groundwater and subsurface sources. Although baseflow is essential for sustaining streams during low flow and drought periods, we have little information about how and why it has changed over large regions of the continental United States. The objective of this study was to evaluate how changes in the climate system have affected observed monthly baseflow records at 3,283 USGS gauges over the last 30 years (1989–2019). We developed a statistical modeling framework to determine the relationship between monthly baseflow and monthly climate predictors (i.e., precipitation, temperature, and antecedent wetness). Overall, we found that baseflow trends and the factors influencing them vary by region and month. In the US Northeast, increases were detected earlier in the year (February and March) and in the summer (May and June), and were likely due to increasing precipitation, warmer temperature, and subsequent changes in snowmelt. Increasing baseflow in the US Pacific Northwest and Midwest were associated with increases in precipitation and antecedent wetness throughout the year. Decreasing trends were located in the US Southeast and Southwest. Baseflow trends in the US Southeast were only detected in March, possibly as a result of decreased precipitation during the spring. On the other hand, decreases in baseflow in the Central Southwestern United States occurred throughout the year. These trends were associated with a lack of precipitation and increases in temperature. Finally, we examined the relationship between monthly baseflow trends and changes in total water storage using monthly Gravity Recovery and Climate Experiment mascon products from the Jet Propulsion Laboratory. In this study, trends in total water storage were strongly associated with baseflow trends across the United States. The spatial and temporal variability in baseflow response to climate reported here can aid water managers in adapting to future climate change.

continental United States↗
USGS2009

Flood of April 2007 and flood-frequency estimates at streamflow-gaging stations in western Connecticut

A spring nor’easter affected the East Coast of the United States from April 15 to 18, 2007. In Connecticut, rainfall varied from 3 inches to more than 7 inches. The combined effects of heavy rainfall over a short duration, high winds, and high tides led to widespread flooding, storm damage, power outages, evacuations, and disruptions to traffic and commerce. The storm caused at least 18 fatalities (none in Connecticut). A Presidential Disaster Declaration was issued on May 11, 2007, for two counties in western Connecticut—Fairfield and Litchfield. This report documents hydrologic and meteorologic aspects of the April 2007 flood and includes estimates of the magnitude of the peak discharges and peak stages during the flood at 28 streamflow-gaging stations in western Connecticut. These data were used to perform flood-frequency analyses. Flood-frequency estimates provided in this report are expressed in terms of exceedance probabilities (the probability of a flood reaching or exceeding a particular magnitude in any year). Flood-frequency estimates for the 0.50, 0.20, 0.10, 0.04, 0.02, 0.01, and 0.002 exceedance probabilities (also expressed as 50-, 20-, 10-, 4-, 2-, 1-, and 0.2- percent exceedance probability, respectively) were computed for 24 of the 28 streamflow-gaging stations. Exceedance probabilities can further be expressed in terms of recurrence intervals (2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence interval, respectively). Flood-frequency estimates computed in this study were compared to the flood-frequency estimates used to derive the water-surface profiles in previously published Federal Emergency Management Agency (FEMA) Flood Insurance Studies. The estimates in this report update and supersede previously published flood-frequency estimates for streamflowgaging stations in Connecticut by incorporating additional years of annual peak discharges, including the peaks for the April 2007 flood. In the southwest coastal region of Connecticut, the April 2007 peak discharges for streamflow-gaging stations with records extending back to 1955 were the second highest peak discharges on record; the 1955 annual peak discharges are the highest peak discharges in the station records. In the Housatonic and South Central Coast Basins, the April 2007 peak discharges for streamflow-gaging stations with records extending back to 1930 or earlier ranked between the fourth and eighth highest discharges on record, with the 1936, 1938, and 1955 floods as the largest floods in the station records. The peak discharges for the April 2007 flood have exceedance probabilities ranging between 0.10 to 0.02 (a 10- to 2-percent chance of being exceeded in a given year, respectively) with the majority (80 percent) of the stations having exceedance probabilities between 0.10 to 0.04. At three stations—Norwalk River at South Wilton, Pootatuck River at Sandy Hook, and Still River at Robertsville—the April 2007 peak discharges have an exceedance probability of 0.02. Flood-frequency estimates made after the April 2007 flood were compared to flood-frequency estimates used to derive the water-surface profiles (also called flood profiles) in FEMA Flood Insurance Studies developed for communities. In general, the comparison indicated that at the 0.10 exceedance probability (a 10-percent change of being exceeded in a given year), the discharges from the current (2007) flood-frequency analysis are larger than the discharges in the FEMA Flood Insurance Studies, with a median change of about +10 percent. In contrast, at the 0.01 exceedance probability (a 1-percent change of being exceeded in a year), the discharges from the current flood-frequency analysis are smaller than the discharges in the FEMA Flood Insurance Studies, with a median change of about -13 percent. Several stations had more than + 25 percent change in discharges at the 0.10 exceedance probability and are in the following communities: Winchester (Still River at Robertsville, +50 percent change); Hamden (Mill River near Hamden, +46 percent change); Woodbury (Weekeepeemee River at Hotchkissville, +29 percent change); and Newtown (Pootatuck River at Sandy Hook , +28 percent change). Although the majority of the streamflow-gaging stations had discharges at the 0.01 exceedance probability smaller than in the Flood Insurance Studies, the (2007) flood-frequency estimates were larger than in the Flood Insurance Studies for stations in the following communities: Hamden (Mill River near Hamden, +53 percent change); Thomaston (Naugatuck River at Thomaston, +27 percent change); Newtown (Pootatuck River at Sandy Hook, +18 percent change); and Wallingford (Quinnipiac River at Wallingford, +13 percent change). The 1-percent exceedance probability (100-year flood) elevations at streamflow-gaging stations exceeded the FEMA projected 100-year flood elevations by more than +0.5 feet in two Flood Insurance Studies in the communities of Wallingford (Quinnipiac River at Wallingford, +0.6 feet change) and Hamden (Mill River near Hamden, + 2.3 feet change).

Connecticut↗
USGS2020

Geologic map and borehole stratigraphy of Hinkley Valley and vicinity, San Bernardino County, California

Hinkley Valley, in the central to western Mojave Desert of southeastern California, has a long historical record owing to its position as a crossroads for rail and road traffic and its position adjacent to the Mojave River. Subflow in the Mojave River provided groundwater recharge that maintained water consumption and demand by way of shallow wells for local agriculture in the valley. Its crossroads position led to construction of several power-transmission lines, pipeline, and communications cable routes that transect Hinkley Valley. One of these, a natural gas pipeline and its associated compressor station, was the locus of hexavalent chromium, Cr(VI), released into, and consequent contamination of, groundwater. Understanding the movement and fate of the contaminants is a complex hydrologic and geochemical problem. Geologic mapping of the Hinkley Valley area provides framework elements for use in resolving this problem. This report provides new information on surface and subsurface geology to better constrain the origin and geometry of hydrologically important deposits in the Hinkley Valley area and describes youthful faults that may control sediment distribution and groundwater flow. The geologic map (sheet 1) presents substantial new information on surficial geology, including Pliocene deposits, but does not contain significant new work on bedrock. Bedrock investigations were specific to identifying youthful faults and representative outcrops for rocks that were penetrated by boreholes in the valley. Special attention was placed on locating and describing youthful faults. In addition, we analyzed gravity data to (1) map horizontal gradients that we interpret to reflect long-term fault traces and to (2) estimate the depth to bedrock, which is defined as Miocene and older intrusive and metamorphic rocks for the purposes of this report. The subsurface geology of Hinkley Valley was investigated by examining borehole sediment cores and rock encountered at the base of the sediment section. We analyzed the core to determine depositional environments, provenance, and age of the sediment that infilled the valley. Valleys, mountains, and basins in the Hinkley Valley area are topographically complex and incompletely named. The nearly flat floored Hinkley Valley slopes gently northward. It is framed by Mount General and the informally named “Hinkley hills” (southeast of Mount General) on the northeast and by Iron Mountain and Lynx Cat Mountain on the southwest, although breaks in the western mountains allow stream connections between Hinkley Valley and another valley to the west that is herein referred to as Hawes valley. At its south end, Hinkley Valley is traversed by the entrenched Mojave River, which passes east out of the valley past Barstow. North of Hinkley Valley, a few low hills (including Red Hill) separate the valley from a broad west-sloping piedmont that is part of the physiographic Harper Basin (of which the Harper Lake playa is the center). The lower part of this piedmont, however, is referred to as Water Valley, although it is not a distinct valley. The name derives from groundwater sourced from subflow in the Mojave River, which caused shallow water and even artesian flow in Water Valley but not in other parts of the Harper Basin. When water filled the Harper Basin to form Pleistocene Lake Harper it not only submerged Water Valley but also northern Hinkley Valley.

California↗
USGS1996

A catastrophic flood caused by drainage of a caldera lake at Aniakchak Volcano, Alaska, and implications for volcanic hazards assessment

Aniakchak caldera, located on the Alaska Peninsula of southwest Alaska, formerly contained a large lake (estimated volume 3.7 × 10 9 m 3 ) that rapidly drained as a result of failure of the caldera rim sometime after ca. 3400 yr B.P. The peak discharge of the resulting flood was estimated using three methods: (1) flow-competence equations, (2) step-backwater modeling, and (3) a dam-break model. The results of the dam-break model indicate that the peak discharge at the breach in the caldera rim was at least 7.7 × 10 4 m 3 s −1 , and the maximum possible discharge was ≈1.1 × 10 6 m 3 s −1 . Flow-competence estimates of discharge, based on the largest boulders transported by the flood, indicate that the peak discharge values, which were a few kilometers downstream of the breach, ranged from 6.4 × 10 5 to 4.8 × 10 6 m 3 s −1 . Similar but less variable results were obtained by step-backwater modeling. Finally, discharge estimates based on regression equations relating peak discharge to the volume and depth of the impounded water, although limited by constraining assumptions, provide results within the range of values determined by the other methods. The discovery and documentation of a flood, caused by the failure of the caldera rim at Aniakchak caldera, underscore the significance and associated hydrologic hazards of potential large floods at other lake-filled calderas.

Geological Society of America Bulletin↗
USGS1994

Hydrology and potential for ground-water development in southeastern Tooele Valley and adjacent area in the Oquirrh Mountains, Tooele County, Utah

Communities in southeastern Tooele Valley, Utah, are growing, and future demand for water is expected to increase. To prepare for this demand, local surface- and ground-water resources were evaluated. Average streamflow in Settlement, Middle, and Soldier Canyons is about 6,000, 2,100, and 3,900 acre-feet per year, respectively. The combined average perennial streamflow of Pine, Pole, Swensons, Leavetts, and Pass Canyons is about 700 acre-feet per year. Average ground-water recharge to basin-fill deposits in southeastern Tooele Valley is about 44,000 acre-feet per year. Discharge approximately equals recharge. Specific capacity of wells in the basin fill ranges from less than 1 to 180 gallons per minute per foot of drawdown, and dissolved-solids concentration ranges from 363 to 1,550 milligrams per liter. Stream-channel deposits are recharged mainly by streamflow losses and subsurface inflow. Average discharge from stream-channel deposits in Settlement and Middle Canyons is about 2,100 and 3,400 acre-feet per year, respectively. Specific capacity of wells in the stream-channel deposits ranges from less than 1 to 45 gallons per minute per foot of drawdown, and dissolved-solids concentration ranges from 320 to 350 milligrams per liter. Average ground-water recharge to consolidated rock is about 42,000 acre-feet per year. Discharge, mainly by subsurface outflow to southeastern Tooele Valley, approximately equals recharge. Locations of springs in consolidated rock are not correlated with known topographic or geologic features. Specific capacity of wells in the consolidated rock ranges from less than 1 to 97 gallons per minute per foot of drawdown, and dissolved-solids concentration ranges from 220 to 1,400 milligrams per liter. Areas southwest of Tooele City and near Lincoln are considered to have potential for additional ground-water withdrawal.

Utah↗
USGS1987

Hydrology of the U.S. Army Pinon Canyon maneuver site, Las Animas County, Colorado

The U.S. Department of the Army (Fort Carson Military Reservation) has acquired 381 sq mi of semiarid rangeland in southeastern Colorado for mechanized military maneuvers. The study area, known as the Pinon Canyon Maneuver Site, drains into the Purgatoire River, a major tributary of the upper Arkansas River. A multidisciplined hydrologic investigation began in October 1982. The primary aquifer in the Maneuver Site is the Dakota-Purgatoire. Well yields generally range from 10 to 500 gal/min. Dissolved solids concentrations in groundwater ranged from 195 to 6,150 mg/L. Streamflow in the Purgatoire River is perennial. Tributaries draining the Maneuver Site are intermittent or ephemeral and contribute only about 4.4% of the streamflow of the Purgatoire River downstream from the Maneuver Site. Flood frequencies were calculated by using the log Pearson III procedure and compared well with a regional estimating technique that was developed that uses physical drainage-basin characteristics. Calcium and sulfate are the predominant ions in the surface water of the area. Time-series plots indicate that instream water-quality standards for nitrate and metals are exceeded. About 80% of the suspended-sediment load is transported by rainfall runoff, which occurs less than 8% of the time. Ephermal tributaries contributed less than 25% of the suspended-sediment load transported to the Purgatoire River downstream from the Maneuver Site. Historic annual mean sediment yields were measured for 29 small watersheds. Sediment yields were measured for 29 small watersheds. Sediment yields ranged from 9.5 to 1,700 tons/sq mi. Sediment yields were estimated by a multiple-linear-regression model developed by using physical drainage-basin characteristics and by the Pacific Southwest Interagency Committee method. (USGS)

Water-Resources Investigations Report↗