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At least 1,711 records · Page 95Linked to original sources

Environmental assessment of water, sediment, and biota collected from the Bear Creek watershed, Colusa County, California

The Cache Creek watershed lies within California's North Coast Range, an area with abundant geologic sources of mercury (Hg) and a long history of Hg contamination (Rytuba, 2000). Bear Creek, Cache Creek, and the North Fork of Cache Creek are the major streams of the Cache Creek watershed, encompassing 2978 km 2 . The Cache Creek watershed contains soils naturally enriched in Hg as well as natural springs (both hot and cold) with varying levels of aqueous Hg (Domagalski and others, 2004, Suchanek and others, 2004, Holloway and others 2009). All three tributaries are known to be significant sources of anthropogenically derived Hg from historic mines, both Hg and gold (Au), and associated ore storage/processing sites and facilities (Slotton and others, 1995, 2004; CVRWQCB, 2003; Schwarzbach and others, 2001; Gassel and others, 2005; Suchanek and others., 2004, 2008a, 2009). Historically, two of the primary sources of mercury contamination in the upper part of Bear Creek have been the Rathburn and Petray Hg Mines. The Rathburn Hg mine was discovered and initially mined in the early 1890s. The Rathburn and the more recently developed Petray open pit mines are localized along fault zones in serpentinite that has been altered and cut by quartz and chalcedony veins. Cold saline-carbonate springs are located perepheral to the Hg deposits and effluent from the springs locally has high concentrations of Hg (Slowey and Rytuba, 2008). Several ephemeral tributaries to Bear Creek drain the mine area which is located on federal land managed by the U.S. Bureau of Land Management (USBLM). The USBLM requested that the U.S. Geological Survey (USGS) measure and characterize Hg and other geochemical constituents in sediment, water, and biota to establish baseline information prior to remediation of the Rathburn and Petray mines. Samples sites were established in Bear Creek upstream and downstream from the mine area. This report is made in response to the USBLM request, the lead agency mandated to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) - Removal Site Investigation (RSI). The RSI applies to the possible removal of Hg-contaminated mine waste from Bear Creek. This report summarizes data obtained from field sampling of water, sediment, and biota in Bear Creek, above input from the mine area and downstream from the Rathburn-Petray mine area to the confluence with Cache Creek. Our results permit a preliminary assessment of the chemical constituents that could elevate levels of monomethyl Hg (MMeHg) in Bear Creek and its uptake by biota and provide baseline information for comparison to conditions after mine remediation is completed.

California↗

Regional geochemical maps of the Tonopah 1 degree by 2 degrees Quadrangle, Nevada, based on samples of stream sediment and nonmagnetic heavy-mineral concentrate

This report is part of a series of geologic, geochemical, and geophysical maps of the Tonopah 1° x 2° quadrangle, Nevada, prepared during studies of the area for the Conterminous United States Mineral Assessment Program (CUSMAP). Included here are 21 maps showing the distributions of selected elements or combinations of elements. These regional geochemical maps are based on chemical analyses of the minus-60 mesh (0.25 mm) fraction of stream-sediment samples and the nonmagnetic heavy-mineral concentrate derived from stream sediment. Stream sediments were collected at 1,217 sites. Our geochemical studies of mineralized rock samples provide a framework for evaluating the results from stream sediments. The Tonopah 1° x 2° quadrangle comprises about 19,100 km 2 (7,450 mi 2 ) in west-central Nevada (fig. 1). Topography is typical of the Basin and Range province, consisting of angular mountain ranges separated by broad valleys that comprise about half the area. Topographic relief is generally about 1,000 m but in some places is more than 1,500 m. Most of the ranges have well-developed drainages in steep-walled canyons occupied by intermittent streams. The climate is semi-arid to arid. Pinon pine and juniper grow in most places at elevations above 2,100 m, and sagebrush is abundant at lower elevations. Major access is provided by U.S. Routes 6 and 95, and there are numerous county maintained gravel roads and unmaintained jeep trails. Bedrock geology of the Tonopah quadrangle is a complex mosaic of late Precambrian to Tertiary rocks juxtaposed by numerous thrust and high-angle faults. Useful geologic summaries can be found in reports by Ross (1961), Albers and Stewart (1972), Stewart and Carlson (1978), and Kleinhampl and Ziony (1985). Mineral prospects and mines occur in igneous, metamorphic, and sedimentary rocks of all ages, and mines are particularly abundant in the central and western parts of the quadrangle. The complex geology produces clasts of mixed lithology in alluvium in all drainage basins sampled in this study, and the numerous mines and prospects probably contaminate many drainages. The geochemical maps in this report are based on analytical results reported by Fairfield and others (1985), Hill and others (1986), and Siems and others (1986). These reports also describe the sample preparation and analytical methods and provide information on the location of the sample sites.

Nevada↗

Composite geochemical map of anomalous lead and zinc distribution in the Tanacross Quadrangle, Alaska

This geochemical map shows drainage basins in which either anomalous lead, zinc, or both lead and zinc values were detected in at least one of four sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, (C) the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level, and (D) the ash of aquatic bryophytes (mosses). The anomaly patterns were derived from the point-plot maps of lead and zinc distribution in the individual sample media. (Curtin, Day, O'Leary, Marsh, and Tripp, 1976a, b). Background data were disregarded for each of the two metals. Weakly anomalous data for all media (small black symbols) were assigned the number 2; strongly anomalous data for all media (large black symbols) were assigned the number 3. These new data were then summed or "stacked" for each metal so that all sites showing anomalous values in one or more of the sample media had a numerical rating that ranged from 2 (weakly anomalous value in one sample media) to a possible 12 (strongly anomalous values in all four sample media). The summed data were ranked into the three groups shown in the explanation. The drainage basins showing anomalous values were outlined according to these groups. As a final step the composite lead anomaly map was then superimposed on that of zinc to give this composite lead-zinc map.

Alaska↗

Low-flow characteristics of small streams in proposed Public Law 566 basins

Low-flow characteristics of Wisconsin streams in basins considered for work under Public Law 566 are presented in this report. The low-flow characteristics presented are the annual minimum 1-day mean flow below which the flow will fall on the average of once in 2 years (Q7,2) and the annual minimum 7-day mean flow below which the flow will fall on the average of once in 10 years (Q7,10). The low-flow characteristics are presented for 278 project sites in 32 basins considered for work under Public Law 566. They were determined by correlating base-flow measurements at the project site to the concurrent daily mean flow at continuous-record gaging stations in the area. The Q7,2 and Q7,10 discharges determined by a frequency analysis at the continuous-record gaging stations were used to estimate the Q7,2 an Q7,10 at the project sites. The accuracy of the estimated low-flow characteristics is evaluated according to the type and amount of data available used. The statewide average of the accuracy determined by the standard error of estimate for the 10-year low flow (SE7,10)> based on three base-flow measurements, is 45 percent but differs within the State.

Wisconsin↗

Map showing geochemistry of stream sediments in the Jerry Peak Wilderness Study Area, Custer County, Idaho

The Jerry Peak Wilderness Study Area is about 25 mi south of Challis in Custer County, central Idaho (fig. 1). The study area contains 46,150 acres of land administered by the by the Bureau of Land Management and 1 sq mi owned by the State of Idaho, a total of 46,790 acres. Most of the study area is readily accessible by roads along tributaries of the East Fork Salmon River, especially Road Creek, Herd Creek, and Lake Creek. The southeastern part of the area can be reached from Road Creek by the road down Peck's Canyon and by roads from Thousand Springs Valley, southeast of the study area. Several access roads to past logging operations extend up Sage Creek and its tributaries in the southeast part of the study area. Access to points within the northern part of the area is facilitated by jeep trails that connect with Road Creek and lake Creek and by improved road that extends northward from Herd Lake. The study area is moderately rugged, with local relief approaching 2,000 ft. Jerry (10,010 ft), the highest point within the area, is a low knoll on a north-trending linear ridge (fig. 1). The ridge has not been glaciated, despite its relatively high altitude. Most of the area is thinly covered by grass and low shrubs; trees, for the most part, are restricted to valley bottoms or to local, small groves on hillslopes.

Idaho↗

Composite geochemical map of anomalous copper and molybdenum distribution in the Tanacross Quadrangle, Alaska

This geochemical map delineates drainage basins in which either anomalous copper, molybdenum, or both copper and molybdenum were detected in at least one of four sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, (C) the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level, and (D) the ash of aquatic bryophytes (mosses). The anomaly patterns were derived from the point-plot maps of copper and molybdenum distribution in the individual sample media (Curtain, Day, O'Leary, Marsh, and Tripp, 1976; Curtain, Day, Carten, Marsh, and Tripp, 1976). Background data were disregarded for each of the two metals. Weakly anomalous data for all media (small black symbols) were assigned the number 2; strongly anomalous data for all media (large black symbols) were assigned the number 3. These new data were then summed or "stacked" for each metal so that all sites showing anomalous values in one or more of the sample media had a numerical rating that ranged from 2 (weakly anomalous value in one sample medium) to a possible 12 (strongly anomalous values in all four sample media). The summed data were ranked into three groups shown in the explanation. The drainage basins showing anomalous values were outlined according to these groups. As a final step the composite copper anomaly map was superimposed on that of molybdenum to give this composite copper-molybdenum map.

Alaska↗

Limnology of selected lakes in Ohio, 1975

Water-quality reconnaissance by the U.S. Geological Survey and Ohio Environmental Protection Agency, to evaluate the status of Ohio's lakes and reservoirs was begun in 1975 with studies of 17 lakes. Spring and summer data collections for each lake included: profile measurements of temperature, dissolved oxygen, pH, and specific conductance; field and laboratory analyses of physical, biological, chemical organic characteristics; (nutrient), and concentrations of major and minor chemical constituents from composites of the water column; and physical and chemical data from major inflows. Light penetration (secchi disk) ranged from 9.4 feet (2.9 meters) in Lake Hope to 0.4 feet (0.1 meter) in Acton Lake. Seasonal thermal stratification or stability is shown for 10 lakes deeper than 15 feet (4.6 meters). Unstable or modified temperature profiles were observed in shallow lakes (depths less than 15 feet) or lakes controlled through subsurface release valves. Dissolved oxygen saturation ranged from 229 percent (20.8 milligrams per liter) in the epilimnion of Paint Creek Lake to zero in the bottom waters of all thermally stabilized lakes. Marked chemical and physical differences and nutrient uptake and recycling developed within different thermal strata. Anaerobic zones were frequently characterized by hydrogen sulfide and ammonia. Calcium was the dominant or codominant cation, and bicarbonate and(or) sulfate were the major anions in all lakes sampled. Only Hope and Vesuvius Lakes had soft water (hardness less than 61 milligrams per liter as CaCO3 ), and both lakes were further characterized by low pH (less than 7.0). Specific conductance ranged from 510 micromhos (Deer Creek and Salt Fork Lakes) to 128 micromhos (Lake Hope). Pesticide residues were detected in Acton Lake, and concentrations of one or more trace metals were at or above Ohio Environmental Protection Agency recommended limits in 11 lakes. Fecal coliform colony counts were below 400 colonies per 100 milliliters in 13 lakes; higher counts were observed in Acton, Cowan, Harrison, and Paint Creek Lakes in samples taken during runoff events. Phytoplankton densities greater than 100,000 cells per milliliter were observed in 12 lakes and reached a maximum of over 2,800,000 cells per milliliter in Grand Lake St. Marys. Summer domination of the algal community by blue-green algae (Cyanophyta) was indicated for 16 of the 17 lakes. Streams are a major source of macronutrients to Ohio's lakes. Concentrations of nitrite plus nitrate and total Phosphorus in 38 inflow samples to the 17 lakes averaged 2.17 milligrams per liter as N and 0.29 milligrams per liter as P, respectively.

Ohio↗

Landfill leachate contributes per-/poly-fluoroalkyl substances (PFAS) and pharmaceuticals to municipal wastewater

Widespread disposal of landfill leachate to municipal sewer infrastructure in the United States calls for an improved understanding of the relative organic-chemical contributions to the wastewater treatment plant (WWTP) waste stream and associated surface-water discharge to receptors in the environment. Landfill leachate, WWTP influent, and WWTP effluent samples were collected from three landfill-WWTP systems and compared with analogous influent and effluent samples from two WWTPs that did not receive leachate. Samples were analyzed for 73 per-/poly-fluoroalkyl substances (PFAS), 109 pharmaceuticals, and 21 hormones and related compounds. PFAS were detected more frequently in leachate (92%) than in influent (55%). Total PFAS concentrations in leachate (93,100 ng/L) were more than ten times higher than in influent (6,950 ng/L), and effluent samples (3,730 ng/L). Concentrations of bisphenol A; the nonprescription pharmaceuticals cotinine, lidocaine, nicotine; and the prescription pharmaceuticals amphetamine, carisoprodol, pentoxifylline, and thiabendazole were an order of magnitude higher in landfill leachate than WWTP influent. Leachate load contributions for PFAS (0.78 to 31 g/d), bisphenol A (0.97 to 8.3 g/d), and nonprescription (2.0 to 3.1 g/d) and prescription (0.48 to 2.5 g/d) pharmaceuticals to WWTP influent were generally low (<10 g/d) for most compounds because of high influent-to-leachate volumetric ratios (0.983). No clear differences in concentrations were apparent between effluents from WWTPs receiving landfill leachate and those that did not receive landfill leachate.

Environmental Science: Water Research & Technology↗

Aeromagnetic map of the Rattlesnake Roadless Area, Coconino and Yavapai counties, Arizona

The Rattlesnake Road less Area covers 32,870 acres between long 11&deg;37'30" and long 111&deg;47'30" W. and between lat 34&deg;40' and lat 34&deg;45' N., Coconino and Yavapai Counties, in central Arizona. Sedona and 0ak Creek, the nearest population centers, are located, respectively, at the northwest corner and along the west boundary of the roadless area. The Rattlesnake Roadless Area includes the deeply embayed Mogollon Rim margin of the Colorado Plateau Province and part of the Werde Walley. The Werde Walley is a deeply dissected lacustrine basin, one of several tectonic basins in the Arizona transition zone that separate the Basin and Range Province from the Colorado Plateau Province. Here the plateau surface falls off abruptly to the Werde Valley, drained by the Werde River, the master stream of the region. The highest point in the roadless area is 6,834 ft at the basalt cap at the north end of Munds Mountain. The lowest point, about 3,480 ft, is along Dry Beaver Creek, near the southwest corner of the roadless area. The maximum relief, more than 2,000 ft, occurs between the Munds-Lee Mountain divide and the valley floors of bordering Oak Creek and Jacks Canyon. The relief between floor and upper canyon rims along the steep-walled and narrow Woods Canyon ranges from 900 ft to more than 1,400 ft; the east side of the canyon has the highest walls. Canyon rims in the roadless area are accessible by several four-wheel-drive trails across the plateau surface from points along Schnebly Hill Road and Highway I-17. Access to Jacks Canyon is by road and four-wheel-drive trail to Jacks Canyon Tank, about 4 mi up the canyon from Highway 179. Access to the head of Jacks Canyon is by foot or horse along a well-maintained trail. Access to the bottom of Woods Canyon is by four-wheel-drive vehicle for about 2 mi from Highway 179 and then by pack trail for about 5 mi more.

Arizona↗

Assessment of long-term changes in surface-water extent within Klamath Marsh, south-central Oregon, 1985–2021

The annual maximum extent of surface water in Klamath Marsh has naturally fluctuated in response to periods of wet and dry conditions in the surrounding basin. Field observations during the 2010s indicate that the annual maximum extent of surface water has been declining and the marsh is not responding to hydrologic inputs as it had historically. This report describes the results of a hydrologic evaluation of Klamath Marsh to characterize and understand multi-year declines in the surface-water extent and increased intermittency of streamflow exiting the marsh. Landsat imagery collected during 1985–2021 was processed to create a time series of annual maximum surface-water extent to assess changes in surface-water inundation within the marsh. A 50-percent decrease in the mean surface area of annual total open-water extent (TOWE) during the latter half of the study period (2003–21) compared to the first half (1985–2003) was observed in this 37-year time-series dataset. The change in open-water extent was offset by a corresponding increase in dry land in the marsh. Time series of streamflow, groundwater level, total annual precipitation, annual mean temperature, and anthropogenic water use and water management were compiled and evaluated to improve understanding of the factors affecting TOWE. Statistically significant downward trends in the regional groundwater table and streamflow into and out of the marsh were identified as well as statistically significant upward trends in annual mean temperature. Statistically significant correlations among TOWE, streamflow, and groundwater level also were identified. The decreasing trends could not be attributed to changes in total annual precipitation or changing anthropogenic groundwater use within the study area. Declines in the open-water extent of Klamath Marsh since 2000 principally are due to a decoupling of the groundwater and surface-water system beneath the marsh because of regional declines in groundwater level. Regional increases in air temperature and the reestablishment of more than 55,000 acres of forested land within the study area have likely contributed to increasing evapotranspiration, leaving less water available for groundwater recharge and stream base flow and resulting in basin-wide declines in streamflow and groundwater levels.

Oregon↗

Simulation of the regional groundwater-flow system of the Menominee Indian Reservation, Wisconsin

A regional, two-dimensional, steady-state groundwater-flow model was developed to simulate the groundwater-flow system and groundwater/surface-water interactions within the Menominee Indian Reservation. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Menominee Indian Tribe of Wisconsin, to contribute to the fundamental understanding of the region&rsquo;s hydrogeology. The objectives of the regional model were to improve understanding of the groundwater-flow system, including groundwater/surface-water interactions, and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate groundwater/surface-water interactions, provide a framework for simulating regional groundwater-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate groundwater-flow patterns at multiple scales. Simulations made with the regional model reproduce groundwater levels and stream base flows representative of recent conditions (1970&ndash;2013) and illustrate groundwater-flow patterns with maps of (1) the simulated water table and groundwater-flow directions, (2) probabilistic areas contributing recharge to high-capacity pumped wells, and (3) estimation of the extent of infiltrated wastewater from treatment lagoons. The groundwater-flow model described in this report simulates the major hydrogeologic features of the modeled area, including surficial unconsolidated aquifers, groundwater/surface-water interactions, and groundwater withdrawals from existing high-capacity production wells. Areas contributing recharge to pumped high-capacity wells on the Menominee Indian Reservation were delineated by tracking simulated water particles from the water table to wells in combination with Monte Carlo techniques, and maps of the probability of capture for each well nest were produced. Groundwater-agebased areas contributing recharge to wells were simulated by using the calibrated set of parameters and porosity values adjusted to account for bias in simulated saturated thickness. Simulations were performed for current (2013) pumping rates. The simulations show a range in sensitivity of the simulated areas contributing recharge to wells given the parameters evaluated through the Monte Carlo analysis. The areas contributing recharge to supply wells for the villages of Zoar and Neopit are long and narrow, with a sharp gradation from high to low probability of capture. The areas contributing recharge to supply wells for Middle Village and the village of Keshena exhibit a sharp gradation from high to low probability over a relatively small area between the well and a local groundwater mound. The highest probability areas contributing recharge to the supply wells for the Villages of Onekewat and Redwing are in the immediate vicinity of the wells. These wells also have an extensive area with low probability for capturing water that is likely due to a locally low hydraulic gradient and the large degree of uncertainty associated with the lakebed resistance parameters that control interaction between groundwater and local lakes. Additional field investigations and associated local model refinements would facilitate further reductions in uncertainty associated with simulated areas contributing recharge to the wells. The likely extent of the Neopit wastewater plume was simulated by using the groundwater-flow model and Monte Carlo techniques to evaluate the sensitivity of predictive simulations to a range of model parameter values. Wastewater infiltrated from the currently operating lagoons flows predominantly south toward Tourtillotte Creek. Some of the infiltrated wastewater is simulated as having a low probability of flowing beneath Tourtillotte Creek to the nearby West Branch Wolf River. Results for the probable extent of the wastewater plume are considered to be qualitative because the method only considers advective flow and does not account for processes affecting contaminant transport in porous media. Therefore, results for the probable extent of the wastewater plume are sensitive to the number of particles used to represent flow from the lagoon and the resolution of a synthetic grid used for the analysis. Nonetheless, it is expected that the qualitative results may be of use for identifying potential downgradient areas of concern that can then be evaluated using the quantitative &ldquo;area contributing recharge to wells&rdquo; method or traditional contaminant-transport simulations.

Wisconsin↗

Mineral resource potential map of the Mount Eddy and Castle Crags Roadless Areas, Shasta, Siskiyou, and Trinity counties, California

Although ultramafic terranes such as that underlying the Mount Eddy and Castle Crags Roadless Areas may contain chromite, nickel, platinum-group metals, cobalt, and asbestos, there are no significant identified concentrations of these resources within the roadless areas. Platinum-group metals were sought but not detected in stream-sediment concentrates, although this does not rule out their possible occurrence. Nickel and cobalt did not occur in anomalous amounts although slightly higher nickel values in the northern part of the Mount Eddy Roadless Area may indicate low-grade mineralization within small dunite bodies, if the nickel occurs in sulfide phases rather than in olivine. The region has been examined on the surface for chromite and asbestos. Although both minerals are ubiquitous there is probably only a low potential for asbestos on the basis of the small size of veins at the surface. Only a few small areas of chromite were noted in the Mount Eddy Roadless Area; without subsurface data, however, any dunite body must be considered to have potential for chromite. The geochemical data for boron, barium, and mercury plus abundant quartz veining in gabbro and hornblende diorite suggest pervasive hydrothermal alteration, which could have formed mercury or vein gold deposits. Sand and gravel deposits occur in the Castle Crags Roadless Area but they cannot compete with superior deposits closer to markets. At a borrow pit northwest of the Mount Eddy Roadless Area, sheared serpentinite is quarried for road metal; similar rock occurs in the roadless area; however, better material is more readily available elsewhere.

California↗

Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrate, Pyramid Roadless Area, El Dorado County, California

The Wilderness Act (Public Law 88-577, September 3, 1964) and related acts require the U.S. Geological Survey and the U.S. Bureau of Mines to survey certain areas on Federal lands to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. This report presents the results of a geochemical survey of the Pyramid Roadless Area (5203) in the Eldorado National Forest and Lake Tahoe Basin Management Unit, El Dorado County, California. This roadless area was classified as a further planning area during the Second Roadless Area Review and Evaluation (RARE II) by the U.S. Forest Service, January 1979. The Pyramid Roadless Area lies near the crest of the Sierra Nevada about 75 miles east of Sacramento, California. the area, which is adjacent to and almost encircles the Desolation Wilderness, encompasses approximately 31,400 acres in Eldorado National Forest and the Lake Tahoe Basin Management Unit in El Dorado County, California. The area is dominated by deep rugged canyons that run eastward from the Sierra Nevada crest to Lake Tahoe basin and westward toward the Sacramento Valley. Elevations range from about 5,500 feet along Big Silver Creek on the west side of the study area to 8,895 feet at Echo Peak along the southeastern side of the roadless area. Geochemical sampling was conducted during 1982. This report summarizes the results of that investigation and provides details of the geochemical evaluation used in producing the final mineral resource assessment of the study area (Armstrong and others, 1983).

California↗

Geology and underground waters of the Arkansas Valley in eastern Colorado

In the valley of Arkansas River in southeastern Colorado there is an area of considerable extent in which artesian flows are available. During the last ten years numerous wells have been sunk to develop this important resource and, in most cases in the lower lands, abundant water supplies have been obtained. The principal water-bearing bed is the "Dakota" formation, which consists of two sheets of porous sandstone separated by a small body of clay and overlain in the greater portion of the area by a mass of impervious shales. The sandstones receive their waters from, rainfall and from the sinking of streams along the foothills of the Rocky Mountains and on some of the higher slopes south of the Arkansas Valley. In the passage of this sandstone underground, the waters which it contains are held down by the overlying shales, but, as some of the sandstone outcrops are at relatively low levels to the east only a moderate head or pressure is sustained. On account of this low head, artesian flows are available only in the lower lands, and one of the principal objects of this investigation has been the determination of the area in which flows are to be expected. The "Dakota" sandstone and associated formations do not lie level, or even slope regularly to the east, but are flexed into low arches and shallow troughs of considerable complexity of configuration. Accordingly, in investigating this source of water supply, it has been necessary to ascertain the structure and distribution of the various formations in order to indicate the variations in depth to the water-bearing stratum. The principal results of these investigations are set forth: (1) In the geologic map (Pl. VI), which shows the distribution of the formations on the surface; (2) in the map, Pl. XXV, which shows the depth to the water-bearing horizon, the area in which flows are expected, the head of the underground waters, and other features, and (3) in the cross sections (Pls. VII and XXIII), which show the principal underground features. The investigation has been in progress for several years and is an extension of the preliminary examination of the region by G. K. Gilbert in 1894 and 1895. For the western portion of the area the maps and texts of the Pueblo, Elmoro, Walsenburg, Spanish Peaks, and Pikes Peak folios have been utilized as far as practicable. For the central and eastern portions the larger features of the geology have been specially mapped, and considerable detailed mapping has been done in the region south and southeast of Canyon and Colorado Springs. In the field work I have been assisted by Mr. C. A. Fisher, who has examined in detail the Nepesta quadrangle and contributed numerous other data. Dr. W. S. Tangier Smith and Messrs. C. E. Sicbenthal and W. T. Lee have made observations in certain areas. Much valuable information respecting wells has been furnished by Mr. William Archer, of the Atchison, Topeka and Santa Fe Railway Company, and Mr. C. H. McVay, well driller at Rocky Ford.

Colorado↗

Evaluation of landslide monitoring in the Polish Carpathians

In response to the June 15, 2010 request from the Polish Geological Institute (PGI) to the U.S. Geological Survey (USGS) for assistance and advice regarding real-time landslide monitoring, landslide specialists from the USGS Landslide Hazard Program visited PGI headquarters and field sites in September 2010. During our visit we became familiar with characteristics of landslides in the Polish Carpathians, reviewed PGI monitoring techniques, and assessed needs for monitoring at recently activated landslides. Visits to several landslides that are monitored by PGI (the Just, Hańczowa, Szymbark, Siercza and Łasńica landslides) revealed that current data collection (monthly GPS and inclinometer surveys, hourly piezometers readings) is generally sufficient for collecting basic information about landslide displacement, depth, and groundwater conditions. Large landslides are typically hydrologically complex, and we would expect such complexity in Carpathian landslides, given the alternating shale and sandstone stratigraphy and complex geologic structures of the flysch bedrock. Consequently groundwater observations could be improved by installing several piezometers that sample the basal shear zone of each landslide being monitored by PGI. These could be supplemented by additional piezometers at shallower depths to help clarify general flow directions and hydraulic gradients. Remedial works at Hańczowa make the landslide unsuitable for monitoring as part of an early warning network. Monitoring there should focus on continued performance of the remedial works. Our suggestions for new monitoring at recently activated landslides are summarized in table 1. Displacement monitoring using extensometers and (or) GPS is a high priority at Kłodne, Łaśnica, Łazki, and Siedloki. Geomorphologic mapping of active surface features (scarps, cracks, shear zones, folds, and thrusts) in sufficient detail to reveal the kinematics of each landslide would greatly help in planning subsurface exploration and monitoring. Mapping should take advantage of existing and future airborne lidar data sets of specific areas, where available. Borehole inclinometers and piezometers would complete the basic monitoring package for these landslides. The landslide at Kłodne may be well suited for more detailed monitoring for landslide process research, although research opportunities exist at the other landslides as well. The landslide near Siedloki may be a good candidate for terrestrial laser scanning (TLS). Tandem streamflow gages upstream and downstream from the Siedloki landslide, or laser distance meters to monitor advancement of the toe, may be needed to provide warning of stream blockage of Potok Milowski. A real-time warning system specifically for the Łazki landslide might be considered due to potential concerns about catastrophic movement into Międzybrodzie Reservoir. Challenges associated with the establishment of a complete real-time monitoring and early warning system are far greater than just the technical and logistical aspects of installing remote monitoring systems at a large number of landslides. Long-term maintenance of a landslide monitoring network will involve considerable effort and expense as sensors break-down from exposure to weather, landslide movement, and harsh underground environmental conditions. Once PGI&rsquo;s planned pilot network of 10-20 monitored landslides is operating, a period of observation and analysis will be needed to establish appropriate alert levels and criteria for issuing alerts and warnings. Simultaneously, discussions with authorities will be needed to develop action plans for responding to landslide notifications and (or) warnings. Public resistance to landslide warnings and mandated evacuations may be high given the low historical incidence of fatalities and injuries resulting from Carpathian landslides and the small potential for warnings to reduce landslide damage to homes and land. Careful weighing of purpose, advantages, and costs of a large-scale monitoring and early warning program is needed early in the planning process and should be revisited regularly throughout pilot and final implementation. In this report, we present a generic plan for monitoring of a hypothetical Carpathian landslide that illustrates how our suggestions for each of the specific landslides could be implemented. The plan includes basic pore pressure, displacement, and weather monitoring, along with supplemental monitoring for special conditions at specific landslides. Table 2 summarizes the overall approach and basic equipment and software requirements.

Open-File Report↗

Comparison of load estimation techniques and trend analysis for nitrogen, phosphorus, and suspended sediment in the Eucha-Spavinaw Basin, northwestern Arkansas and northeastern Oklahoma, 2002-10

The City of Tulsa, Oklahoma, uses water from Lake Eucha and Spavinaw Lake in the Eucha-Spavinaw basin of northwestern Arkansas and northeastern Oklahoma for public water supply. Increases in algal biomass, which cause taste and odor problems in drinking water produced from the lakes, may be attributable to increases in nitrogen and phosphorus concentrations in the lakes and in streams discharging to the lakes. To evaluate transport of nitrogen, phosphorus, and suspended sediment in this basin, loads and temporal trends were evaluated for five streamflow-gaging stations in the Spavinaw and Beaty Creek basins. Two approaches were used to develop regression equations for estimation of loads and yields of nitrogen, phosphorus, and sediment. The first approach used regression equations referred to as daily mean load (DM L ) regressions, developed from water-quality samples and daily mean streamflow data collected from 2002 through 2010 at five streamflow-gaging stations in the basin. This approach was updated to compare loading results with those used in previous investigations. The second approach used regression equations, referred to as instantaneous continuous (INST C ) regressions, developed from continuous measurements of physical water-quality constituents (specific conductance, temperature, and turbidity, and streamflow data) obtained from 2004 through 2010 to estimate loads of nitrogen, phosphorus, and sediment at two of the streamflow-gaging stations, Spavinaw Creek near Colcord, Okla., and Beaty Creek near Jay, Okla. Daily, annual, and mean annual loads estimated from these two regression methods were compared for the period 2005&ndash;10. Based on estimates obtained using DM L regressions, mean annual loads of 1,640,000 pounds of nitrogen, 99,900 pounds of phosphorus, and 116,000,000 pounds of sediment were transported into Lake Eucha from the Spavinaw and Beaty Creek basins. Estimated annual loads of nitrogen and phosphorus delivered to Lake Eucha from the Spavinaw and Beaty Creek basins during 2002&ndash;10 were 2.5 to 7.8 percent less, respectively, than the loads of those constituents discharged to Lake Eucha from 2002&ndash;09, indicating that nitrogen and phosphorus loads in 2010 were less than loads typical for the period 2002&ndash;09. Daily, annual, and mean annual load estimates varied substantially, depending on streamflow conditions and the independent variables used to develop regressions. Daily and annual loads estimated from INST C regressions that included turbidity, streamflow, temperature, specific conductance, and seasonality fit better with the field data than loads estimated from DM L regressions that included streamflow, seasonality, and time. Loads estimated from the INST C regression generally were greater than those estimated from the DM L regression. Relative percent differences in the mean annual total nitrogen load estimated by the INST C and DM L regressions were within 2 percent for Spavinaw Creek near Colcord, and Beaty Creek near Jay, Okla. The relative percent difference between the two types of regressions for estimates of mean annual total phosphorus loads at the two streamflow-gaging stations was 27.7 for Spavinaw Creek near Colcord, Okla., and only -2.6 percent for Beaty Creek near Jay, Okla. The relative percent difference between mean annual suspended-sediment loads at the streamflow-gaging stations was -38.6 percent for Spavinaw Creek near Colcord, Okla., and -122.7 percent for Beaty Creek near Jay, Okla. The DM L regression may have substantially underestimated phosphorus load at the Spavinaw Creek near Colcord, Okla., streamflow-gaging station in wet years and overestimated sediment load at both streamflow-gaging stations in wet years. Temporal trends in flow-adjusted nitrate-nitrogen, nitrogen, phosphorus, and suspended-sediment concentrations were analyzed for the five streamflow-gaging stations for the period 2001&ndash;10. No significant trends were observed for nitrate plus nitrite-nitrogen or total nitrogen concentrations at any streamflow-gaging station. There were significant upward trends in phosphorus concentrations in water samples collected during base-flow conditions at the Spavinaw Creek near Maysville, Okla., streamflow-gaging station and during runoff conditions for the Beaty Creek near Jay, Okla., streamflow-gaging station (3.5 to 4.2 percent per year). There were significant downward trends in phosphorus concentrations in base-flow and runoff samples collected at the Spavinaw Creek near Cherokee City, Sycamore, and Colcord, Okla., streamflow-gaging stations (-4.9 to -12.9 percent per year). There were significant downward trends in suspended-sediment concentration at the Spavinaw Creek near Maysville, and Sycamore, Okla., and the Beaty Creek near Jay, Okla., streamflow-gaging stations (-1.5 to -1.8 percent per year). No significant trends were detected in suspended-sediment concentration for the Spavinaw Creek near Cherokee City, and Colcord, Okla., streamflow-gaging stations. Possible causes for downward trends in phosphorus concentrations include decreases in phosphorus discharges from a wastewater-treatment plant upstream from the Spavinaw Creek near Cherokee City, Okla., streamflow-gaging station, and implementation of best management practices in the basin. Downward trends in sediment concentrations may be related to effects of best management practices in the basin.

Arkansas, Oklahoma↗

Palaeoseismology of the Vilariça segment of the Manteigas-Bragança fault in northeastern Portugal

The Manteigas-Bragan&ccedil;a fault is a major, 250-km-long, NNE-striking, sinistral strike-slip structure in northern Portugal. This fault has no historical seismicity for large earthquakes, although it may have generated moderate (M5+) earthquakes in 1751 and 1858. Evidence of continued left horizontal displacement is shown by the presence of Cenozoic pull-apart basins as well as late Quaternary stream deflections. To investigate its recent slip history, a number of trenches were excavated at three sites along the Vilari&ccedil;a segment, north and south of the Douro River. At one site at Vale Me&atilde;o winery, the occurrence of at least two and probably three events in the past 14.5 ka was determined, suggesting an average return period of about 5&ndash;7 ka. All three events appear to have occurred as a cluster in the interval between 14.5 and 11 ka, or shortly thereafter, suggesting a return period of less than 2 ka between events within the cluster. In the same area, a small offset rill suggests 2&ndash;2.5 m of slip in the most recent event and about 6.1 m after incision below a c . 16 ka alluvial fill event along the Douro River. At another site along the Vilari&ccedil;a River alluvial plain, NE of the Vale Me&atilde;o site, several trenches were excavated in late Pleistocene and Holocene alluvium, and exposed the fault displacing channel deposits dated to between 18 and 23 ka. In a succession of closely spaced parallel cuts and trenches, the channel riser was traced into and across the fault to resolve c . 6.5 m of displacement after 18 ka and c . 9 m of slip after c . 23 ka. These observations yield a slip rate of 0.3&ndash;0.5 mm/a, which is consistent with earlier estimates. Combining the information on timing at Vale Me&atilde;o winery and displacement at Vilari&ccedil;a argues for earthquakes in the M7+ range, with coseismic displacements of 2&ndash;3 m. This demonstrates that there are potential seismic sources in Portugal that are not associated with the 1755 Lisbon earthquake or the Tagus Valley, and, although rare, large events on the Vilari&ccedil;a fault could be quite destructive for the region. This work provides an analogue for the study of active faulting in intracontinental settings and supports the view that earthquakes within intracontinental settings tend to cluster in time. In addition, this study highlights the usefulness and application of multiple field, remote sensing and geochronological techniques for seismic hazard mitigation.

Manteigas - Braganca fault↗

Geology and ground-water resources of Wichita and Greeley Counties, Kansas

This report describes the geography, geology, and ground-water resources of Wichita and Greeley counties in western Kansas. The area consists of a flat to gently rolling plain, which slopes eastward [at] about 15 feet per mile. A short reach of Ladder Creek (Beaver) is the only perennially flowing stream in the two counties. Ephemeral streams, which flow only during and after heavy rains, are White Woman and Sand Creeks and the western reach of Ladder Creek. The climate is semiarid, the normal annual precipitation being about 17 inches in Wichita County and 16 inches in Greeley County. Agriculture is the principal occupation in the area, and wheat is the most important crop. A considerable area is irrigated; sugar beets and sorghums are the principal irrigated crops. The outcropping rocks range in age from late Cretaceous to Recent; the Smoky Hill chalk member of the Niobrara formation, which is exposed along White Woman Creek in western Greeley County, is the oldest. The Niobrara is almost everywhere overlain by the Ogallala formation of Pliocene age. Generally the Ogallala is overlain by windblown silt of the Pleistocene Sanborn formation, but in places it is exposed along streams. The most recent deposits are dune sand and the alluvium along the streams. The Dakota formation, which is an important aquifer in parts of Kansas, is 300 to 450 feet beneath the Niobrara formation. The ground water that is available to wells in Wichita and Greeley counties is derived entirely from precipitation in the area or in areas immediately west and north. Ground water moves in a generally easterly direction with a gradient that varies inversely with the permeability of the water-bearing beds. The ground-water reservoir is recharged principally by precipitation within the area or within adjacent areas, Ground-water discharge takes place principally by pumping from wells, subsurface outflow, and evaporation and transpiration. Most of the domestic, stock, public, and irrigation supplies are obtained from wells. It is estimated that probably more than 2 billion gallons of water is pumped annually from wells in the area. Since 1947, ground-water recharge has been about equal to ground-water discharge. The use of ground water for irrigation has increased greatly since 1946 and indications are that many more wells may be drilled and pumped without dangerously lowering the water table. Approximately 11,000 to 12,000 acres were irrigated in 1951. A map showing the thickness of water-bearing materials indicates that although much of the area has enough water-bearing material to support irrigation wells, parts of Wichita and Greeley counties have little or none. The Ogallala is the principal water-bearing formation in the area. Small amounts of water may also be obtained locally from alluvial deposits and from cracks in the Niobrara formation. Two deep test wells to the Dakota formation have been drilled but, because of the poor quality of the water, have never been used. The ground water in Wichita and Greeley counties, though hard, is suitable for most purposes. Water from the Ogallala is generally high in fluoride and in some cases may be injurious to the teeth of children. Water from the Dakota, though soft, is unfit for irrigation because of a high content of sodium. The field data upon which most of this report is based are given in tables; they include records of 417 wells, chemical analyses of 31 samples of water, and logs of 57 test holes and wells.

Kansas Geological Survey Bulletin↗