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Seabird tissue archival and monitoring project: Egg collections and analytical results 1999-2002

In 1998, the U.S. Geological Survey Biological Resources Division (USGS-BRD), the U.S. Fish and Wildlife Service (USFWS) Alaska Maritime National Wildlife Refuge (AMNWR), and the National Institute of Standards and Technology (NIST) began the Seabird Tissue Archival and Monitoring Project (STAMP) to collect and cryogenically bank tissues from seabirds in Alaska for future retrospective analysis of anthropogenic contaminants. The approach of STAMP was similar to that of the Alaska Marine Mammal Tissue Archival Project (AMMTAP). AMMTAP was started in 1987 by NIST and the National Oceanic and Atmospheric Administration (NOAA) as part of the Outer Continental Shelf Environmental Assessment Program sponsored by the Minerals Management Service. Presently sponsored by the USGS-BRD, AMMTAP continues its work as part of a larger national program, the Marine Mammal Health and Stranding Response Program. AMMTAP developed carefully designed sampling and specimen banking protocols. Since 1987, AMMTAP has collected tissues from marine mammals taken in Alaska Native subsistence hunts and has cryogenically banked these tissues at the NIST National Biomonitoring Specimen Bank (NBSB). Through its own analytical work and working in partnership with other researchers both within and outside Alaska, AMMTAP has helped to develop a substantial database on contaminants in Alaska marine mammals. In contrast, data and information is limited on contaminants in Alaska seabirds, which are similar to marine mammals in that they feed near the top of the food chain and have the potential for accumulating anthropogenic contaminants. During its early planning stages, STAMP managers identified the seabird egg as the first tissue of choice for study by the project. There is a relatively long history of using bird eggs for environmental monitoring and for investigating the health status of bird populations. Since 1998, protocols for collecting and processing eggs, and cryogenically banking egg samples have been developed by STAMP (see York et al. 2001). Eggs are being collected on an annual basis for several species at nesting colonies throughout Alaska. Aliquots of these egg samples are being analyzed on a regular basis for persistent organic pollutants and mercury. Results of this work have been published in scientific journals (Christopher et al. 2002) and in conference proceedings (Kucklick et al. 2002; Vander Pol et al. 2002a, 2002b). The intent of this report is to provide an up-to-date description of STAMP. The report contains the most recent egg collection inventory, analytical data, preliminary interpretations based on these data, and a discussion of possible future directions of the project.

Report↗

Temporal changes in nutrient concentrations in the Lower Grand River and selected drainage basins, Missouri and Iowa, during the Mississippi River Basin Healthy Watersheds Initiative (2010–23)

This report describes a cooperative study by the U.S. Geological Survey and Missouri Department of Natural Resources that evaluated temporal changes in total nitrogen (TN) and total phosphorus (TP) concentrations in the Lower Grand River hydrologic unit. The study focused on trends since 2010, when the basin was designated as a priority drainage basin of the Mississippi River Basin Healthy Watersheds Initiative (MRBI). At three local drainage basins within the Lower Grand hydrological unit (MRBI sites), stream nutrient trends were evaluated using flow-adjusted (FA) TN and TP concentrations for water years 2011 through 2023. FATN concentration trends were not statistically significant for any MRBI site. One site (site 2) showed a statistically significant increasing trend in FATP concentration, indicating a possible increase in phosphorus sources in parts of the basin. Overall, streamflow variability appeared to be the dominant factor affecting nutrient concentrations at MRBI sites. At five regional drainage basins, including the Grand River and nearby rivers with data from 1994 through 2023 (long-term sites), annual flow-normalized (FN) TN and TP concentrations were evaluated for trends before (water years 2000–10) and during (water years 2010–23) the MRBI. For water years 2010 through 2023, annual FNTN and FNTP concentrations decreased in the Grand River, as well as in the Nodaway and Chariton Rivers, which were not targeted by the MRBI. The Grand River (site 9) reversed from increasing to decreasing FNTP concentrations after 2010, with a 26-percent reduction. Annual FNTN and FNTP concentrations also decreased at the Missouri River sites. While nutrient reductions in the Grand River may reflect the effects of implemented conservation practices, similar trends in nearby, nontargeted rivers and the absence of strong decreasing trends at MRBI sites suggest that broader regional factors, instead of or in addition to MRBI efforts, may have contributed to nutrient reductions in the Grand River.

Iowa, Missouri↗

Ground-water levels in observation wells in Oklahoma, 1969-70

The investigation of the ground-water resources of Oklahoma by the U.S. Geological Survey in cooperation with the Oklahoma Water Resources Board includes a continuing program to collect records of water levels in selected observation wells on a systematic basis. These water-level records: (1) provide an index to available ground-water supplies; (2) facilitate the prediction of trends in water levels that will indicate likely changes in storage; (3) aid in the prediction of the base flow of streams; (4) provide information for use in basic research; (5) provide long-time continuous records of fluctuations of water levels in representative wells; and (6) serve as a framework to which other types of hydrologic data my be related. Prior to 1956, measurements of water levels in observation wells in Oklahoma were included in water-supply papers published annually by the U.S. Geological Survey. Beginning with the 1956 calendar year, however, Geological Survey water-level reports will contain only records of a selected network of observation wells, and will be published at 5-year intervals. The first of this series, for the 1956-59 period was published in 1962. In addition to the water-supply papers, the U.S. Geological Survey, cooperation with the Oklahoma Water Resources Board, has published the following informal reports on water levels in Oklahoma. Ground-water levels in observations wells in Oklahoma, 1956-60 Ground-water levels in observations wells in Oklahoma, 1961-62 Ground-water levels in observations wells in Oklahoma, 1963-64 Ground-water levels in observations wells in Oklahoma, 1965-66 Ground-water levels in observations wells in Oklahoma, 1967-68 Records of water-level measurements in wells in the Oklahoma Panhandle, 1966-70 Records of water-level measurements in wells in the Oklahoma Panhandle, 1971-72 The basic observation-well network in Oklahoma during the period 1969-70 included the following counties: Alfalfa, Beaver, Beckham, Caddo, Cimarron, Cleveland, Garfield, Garvin, Grady, Greer, Harmon, Jackson, Kingfisher, LeFlore, Major, Muskogee, Oklahoma, Payne, Pontotoc, Rogers, Sequoyah, Texas, Tillman, Wagoner, Washita, and Woodward. Table 2 includes the basic observation-well network and other wells measured by the U.S. Geological Survey. The data in this report were compiled and prepared for publication under the cooperative agreement for ground-water investigations in Oklahoma between the Oklahoma Water Resources Board, the U.S. Army Corps of Engineers, the Oklahoma Geological Survey, and the U.S. Geological Survey.

Oklahoma↗

Magnitude and Frequency of Floods on Nontidal Streams in Delaware

Reliable estimates of the magnitude and frequency of annual peak flows are required for the economical and safe design of transportation and water-conveyance structures. This report, done in cooperation with the Delaware Department of Transportation (DelDOT) and the Delaware Geological Survey (DGS), presents methods for estimating the magnitude and frequency of floods on nontidal streams in Delaware at locations where streamgaging stations monitor streamflow continuously and at ungaged sites. Methods are presented for estimating the magnitude of floods for return frequencies ranging from 2 through 500 years. These methods are applicable to watersheds exhibiting a full range of urban development conditions. The report also describes StreamStats, a web application that makes it easy to obtain flood-frequency estimates for user-selected locations on Delaware streams. Flood-frequency estimates for ungaged sites are obtained through a process known as regionalization, using statistical regression analysis, where information determined for a group of streamgaging stations within a region forms the basis for estimates for ungaged sites within the region. One hundred and sixteen streamgaging stations in and near Delaware with at least 10 years of non-regulated annual peak-flow data available were used in the regional analysis. Estimates for gaged sites are obtained by combining the station peak-flow statistics (mean, standard deviation, and skew) and peak-flow estimates with regional estimates of skew and flood-frequency magnitudes. Example flood-frequency estimate calculations using the methods presented in the report are given for: (1) ungaged sites, (2) gaged locations, (3) sites upstream or downstream from a gaged location, and (4) sites between gaged locations. Regional regression equations applicable to ungaged sites in the Piedmont and Coastal Plain Physiographic Provinces of Delaware are presented. The equations incorporate drainage area, forest cover, impervious area, basin storage, housing density, soil type A, and mean basin slope as explanatory variables, and have average standard errors of prediction ranging from 28 to 72 percent. Additional regression equations that incorporate drainage area and housing density as explanatory variables are presented for use in defining the effects of urbanization on peak-flow estimates throughout Delaware for the 2-year through 500-year recurrence intervals, along with suggestions for their appropriate use in predicting development-affected peak flows. Additional topics associated with the analyses performed during the study are also discussed, including: (1) the availability and description of more than 30 basin and climatic characteristics considered during the development of the regional regression equations; (2) the treatment of increasing trends in the annual peak-flow series identified at 18 gaged sites, with respect to their relations with maximum 24-hour precipitation and housing density, and their use in the regional analysis; (3) calculation of the 90-percent confidence interval associated with peak-flow estimates from the regional regression equations; and (4) a comparison of flood-frequency estimates at gages used in a previous study, highlighting the effects of various improved analytical techniques.

Scientific Investigations Report↗

Comparison of Bowen-ratio, eddy-correlation, and weighing-lysimeter evapotranspiration for two sparse-canopy sites in eastern Washington

This report compares evapotranspiration estimated with the Bowen-ratio and eddy-correlation methods with evapotranspiration measured by weighing lysimeters for two sparse-canopy sites in eastern Washington. The sites are located in a grassland area (grass lysimeter site) and a sagbrush- covered area (sage lysimeter site) on the Arid Lands Ecology Reserve in Benton County, Washington. Lysimeter data were collected at the sites from August 1990 to November 1994. Bowen-ratio data were collected for varying periods from May 1993 to November 1994. Additional Bowen-ratio data without interchanging air- temperature and vapor-pressure sensors to remove sensor bias (fixed-sensor system) were collected from October 1993 to June 1994. Eddy-correlation data were collected at the grass lysimeter site from March to April 1994, and at the sage lysimeter site from April to May 1994. The comparisons of evapotranspiration determined by the various methods differed considerably, depending on the periods of record being compared and the sites being analyzed. The year 1993 was very wet, with about 50 percent more precipitation than average; 1994 was a very dry year, with only about half the average precipitation. The study showed that on an annual basis, at least in 1994, Bowen-ratio evapotranspiration closely matched lysimeter evapotranspiration. In 1993, Bowen-ratio and lysimeter evapotranspiration comparisons were variable. Evapotranspiration estimated with the Bowen-ratio method averaged 5 percent more than evapotranspiration measured by lysimeters at the grass lysimeter site from October 1993 to November 1994, and 3 percent less than lysimeters at the sage lysimeter site from November 1993 to October 1994. From March 24 to April 5, 1994, at the grass lysimeter site, the Bowen-ratio method estimated 11 percent less, the Bowen-ratio method utilizing the fixed sensor system about 7 percent more, and the eddy-correlation method about 28 percent less evapotranspiration than the lysimeters measured. From May 7 to June 18, 1993, however, the Bowen-ratio method estimated only 54 percent of the evapotranspiration measured by lysimeters at the grass lysimeter site. This large difference possibly may be attributed to Bowen-ratio instrument variability or error, to the density of grasses in the lysimeters being greater than in the surrounding area, or to heating effects on the lysimeters. From September 1 to October 31, 1993, the Bowen-ratio method estimated more than 450 percent more evapotranspiration than was measured by lysimeters at the sage lysimeter site. This difference may have been due to conditions in the lysimeters at the sage lysimeter site that were unrepresentative of natural conditions. The Bowen-ratio instruments measured evapotrans- piration over sagebrush plants outside the lysimeters, which were blooming very heavily, possibly using supplemental ground water or spring water from nearby upslope areas. The sagebrush plants contained by the lysimeters showed very little evapotranspiration, possibly because they were root-bound and had already used all available water. Also, plants in the lysimeters would not have been able to access any supplemental water available to plants outside the confines of the lysimeters. Earlier in 1993, from June 17 to July 12, the Bowen-ratio method estimated only 1 percent less evapotranspiration than determined for the lysimeters at the sage lysimeter site. On the basis of lysimeter measurements from August 1990 to November 1994, cumulative evapotrans- piration ranged from about 97 to 103 percent of the annual precipitation each year. The evapotranspiration measurements made at the grass and sage lysimeter sites, which were based on weight changes in the lysimeters, showed that storage changes became nearly zero each year some time between August and November as average surface soil moisture decreased to about 2 percent and evapotranspiration rates decreased to less than 0.1 millimeter per day.

Water-Resources Investigations Report↗

Variations in Withdrawal, Return Flow, and Consumptive Use of Water in Ohio and Indiana, with Selected Data from Wisconsin, 1999-2004

This report contains an analysis of water withdrawal and return-flow data for Ohio and withdrawal data for Indiana and Wisconsin to compute consumptive-use coefficients and to describe monthly variability of withdrawals and consumptive use. Concurrent data were available for most water-use categories from 1999 through 2004. Average monthly water withdrawals are discussed for a variety of water-use categories, and average water use per month is depicted graphically for Ohio, Indiana, and Wisconsin (public supply only). For most water-use categories, the summer months were those of highest withdrawal and highest consumptive use. For public supply, average monthly withdrawals ranged from 1,380 million gallons per day (Mgal/d) (November) to 1,620 Mgal/d (July) in Ohio, 621 Mgal/d (December) to 816 Mgal/d (July) in Indiana, and 515 Mgal/d (December) to 694 Mgal/d (July) in Wisconsin. Ohio and Indiana thermoelectric facilities had large increases in average monthly withdrawals in the summer months (5,520 Mgal/d in March to 7,510 Mgal/d in August for Indiana; 7,380 Mgal/d in February to 10,040 Mgal/d in July for Ohio), possibly because of increased electricity production in the summer, a need for additional cooling-water withdrawals when intake-water temperature is high, or use of different types of cooling methods during different times of the year. Average industrial withdrawals ranged from 2,220 Mgal/d (December) to 2,620 Mgal/d (August) in Indiana and from 707 Mgal/d (January) to 787 Mgal/d (August) in Ohio. The Ohio and Indiana irrigation data showed that most withdrawals were in May through October for golf courses, nurseries, and crop irrigation. Commercial water withdrawals ranged from 30.4 Mgal/d (January) to 65.0 Mgal/d (September) in Indiana and from 23.2 Mgal/d (November) to 49.5 Mgal/d (August) in Ohio; commercial facilities that have high water demand in Ohio and Indiana are medical facilities, schools, amusement facilities, wildlife facilities, large stores, colleges, correctional institutions, and national security facilities. Monthly livestock withdrawals were constant for Ohio but were more variable in Indiana and depended on whether the livestock facility operated on a seasonal schedule. Aquaculture withdrawals appeared to correlate with growing seasons and with aeration of ponds during the winter months. Mining withdrawals - specifically, those for nonmetallic mining - tended to be highest in April and may be related to dewatering. Consumptive use and consumptive-use coefficients were computed by two principal methods in this study: the return-flow and withdrawal method (RW; Ohio only) and the winter-base-rate method (WBR; Ohio, Indiana and Wisconsin). The WBR method was not suitable for the thermoelectric, industrial, irrigation, livestock, aquaculture, and mining water-use categories. The RW method was not used for public-supply facilities. A third method, the Standard Industrial Classification code method (SIC), was used only for certain industrial facilities. The public-supply annual average consumptive-use coefficient derived by use of the WBR methods ranged from 6 to 8 percent among Ohio, Indiana, and Wisconsin; the summer average consumptive-use coefficient was considerably higher, ranging from 16 to 20 percent. The commercial annual consumptive-use coefficient for both Ohio and Indiana was 30 percent by the WBR method, which fell within the Ohio annual median (17 percent) and annual average (42 percent) by the RW method. Thermoelectric consumptive use differs greatly by the type of cooling the facility uses; the Ohio annual median consumptive-use coefficient (RW method) was 2 percent for all thermoelectric facilities and facilities with multiple types of cooling, but exclusively once-through-cooling facilities had a median of 0 percent and exclusively closed-loop-cooling facilities had a median of 25 percent. Industrial consumptive-use coefficients varied by type of industry, as reflected by SIC code

Scientific Investigations Report↗

Hydrologic and water-quality characteristics for Calf Creek near Silver Hill, Arkansas, and selected Buffalo River sites, 2001-2002

The Buffalo River and its tributary, Calf Creek, are in the White River Basin in the Ozark Plateaus physiographic province in north-central Arkansas. A better understanding of the hydrology and water quality of Calf Creek is of interest to many, including the National Park Service, which administers the Buffalo National River, to evaluate its effect on the hydrology and water quality of the Buffalo River. The streamflow and water-quality characteristics of Calf Creek near Silver Hill, Arkansas, were compared to two sites on the Buffalo River upstream (near Boxley, Arkansas) and downstream (near St. Joe, Arkansas) from the confluence of Calf Creek for calendar years 2001 and 2002. Annual and seasonal loads were estimated for Calf Creek for nutrients, dissolved organic carbon, and suspended sediment and compared with loads at sites on the Buffalo River. Flow-weighted concentrations and yields were computed from estimated annual loads for comparison with other developed and undeveloped basins. Streamflow varied annually and seasonally at the three sites. The Buffalo River near St. Joe had the largest annual mean streamflow (805 to 1,360 cubic feet per second for 2001 and 2002) compared to the Buffalo River near Boxley (106 and 152 cubic feet per second for 2001 and 2002) and Calf Creek (39 and 80 cubic feet per second for 2001 and 2002). Concentrations of nutrients, suspended sediment, and fecal indicator bacteria generally were greater in samples from Calf Creek than in samples collected from both Buffalo River sites. Bacteria and suspended-sediment concentrations were greater in samples collected during high-flow events at all three sites. The Buffalo River near Boxley had the lowest concentrations for nutrients, suspended sediment, and fecal indicator bacteria. Estimated annual loads of the nutrients, suspended sediment, and organic carbon for 2001 and 2002 demonstrated substantial variability between the three sites and through time. Estimated loads for nutrients at the Buffalo River near St. Joe were 7 to 27 times the median loads estimated for Calf Creek and suspended sediment loads were as much as 120 times greater. Dissolved organic carbon loads were 16 to 20 times greater at the Buffalo River near St. Joe than for Calf Creek. The Buffalo River near Boxley had the smallest annual loads for all constituents except for suspended sediment, which were slightly greater than suspended sediment loads estimated for Calf Creek. Higher loads would be expected at the Buffalo River near St. Joe because of the larger basin area and larger volume of streamflow. Likewise, estimated loads for all three sites were greater during seasons that had greater streamflow than during seasons with more frequent periods of base-flow conditions. The highest daily loads occurred in the fall and winter of 2001 and the winter and spring of 2002.Flow-weighted concentrations generally were higher for Calf Creek than concentrations for the two sites on the Buffalo River and for typical flow-weighted concentrations found in undeveloped basins. However, the flow-weighted concentrations were lower than concentrations in a developed basin. Annual yields calculated for Calf Creek were higher than the two sites on the Buffalo River and sites that are representative of undeveloped basins but lower than a site representative of a developed basin. The Buffalo River near Boxley had yields that were less than the yields typical of undeveloped basins.

Arkansas↗

Groundwater monitoring plan for the Missouri River alluvial aquifer in the vicinity of the City of Independence, Missouri, well field

Source contributions to monitoring and supply wells, contributing recharge areas, groundwater travel times, and current (2012) understanding of alluvial water quality were used to develop a groundwater monitoring plan for the Missouri River alluvial aquifer in the vicinity of the City of Independence, Missouri well field. The plan was designed to evaluate long-term alluvial water quality and assess potential changes in, and threats to, well-field water quality. Source contributions were determined from an existing groundwater flow model in conjunction with particle-tracking analysis and verified with water-quality data collected from 1997 through 2010 from a network of 68 monitoring wells. Three conjunctive factors - well-field pumpage, Missouri River discharge, and aquifer recharge - largely determined groundwater flow and, therefore, source contributions. The predominant source of groundwater to most monitoring wells and supply wells is the Missouri River, and this was reflected, to some extent, in alluvial water quality. To provide an estimate of the maximum potential lead time available for remedial action, monitoring wells where groundwater travel times from the contributing recharge areas are less than 2 years and predominately singular sources (such as the Missouri River or the land surface) were selected for annual sampling. The sample interval of the remaining wells, which have varying travel times and intermediate mixtures of river and land-surface contributions, were staggered on a 2-, 3-, or 4-year rotation. This was done to provide data from similar contributing areas and account for inherent aquifer variability yet minimize sample redundancy.

Missouri↗

Trends in streamflow and precipitation for selected sites in the Elkhorn River Basin and in streamflow in the Salt Creek and Platte River Basins, Nebraska, 1961–2011

To better understand the streamflow trends at the streamgages in the Elkhorn River Basin in Nebraska, the U.S. Geological Survey (USGS) in cooperation with the Lower Elkhorn Natural Resources District further investigated streamflow trends at the eight streamgages on the Elkhorn River, Salt Creek, and the Lower Platte River that indicated a positive trend in streamflow characteristics and analyzed precipitation trends in the four basins upstream from the Elkhorn River Basin streamgages. An analysis of four streamgages in the Elkhorn River Basin, one streamgage in Salt Creek Basin, and three streamgages in the Lower Platte River Basin that had previously indicated trends in selected annual mean streamflow, annual low flows, fall low flows, and growing season monthly mean streamflows metrics were analyzed for the period from 1961 to 2011. A streamgage in the Upper Elkhorn River Basin (Elkhorn River at Neligh, Nebraska [USGS station 06798500; maintained by USGS from water years 1930 to 1993, maintained by Nebraska Department of Natural Resources from water years 1994 to 2019]) had significant positive trends in annual mean streamflow and insignificant trends for other streamflow metrics whereas the lower three sites (Logan Creek near Uehling, Nebr. [USGS station 06799500]; Maple Creek at Nickerson, Nebr. [USGS station 06800000]; and Elkhorn River at Waterloo, Nebr. [USGS station 06800500]) had significant positive trends for annual mean streamflow, for all durations of the annual low-flow periods (1-day, 2-day, 3-day, 7-day, 14-day, 30-day, 60-day, 90-day, and 183-day periods), for all durations of the low-flow periods in October–November (1-day, 2-day, 3-day, 7-day, 14-day, 30-day, and 60-day periods), and for monthly mean streamflow for July, August, and September. Upstream from the confluence of the Elkhorn River and the Platte River, the Platte River at North Bend, Nebr. (USGS station 06796000), streamgage indicated insignificant trends for most streamflow metrics. A streamgage in the Salt Creek Basin (Salt Creek at Greenwood, Nebr. [USGS station 06803555]) also indicated positive trends in some low-flows metrics. Streamflow at the Platte River at Louisville, Nebr. (USGS station 06805500), streamgage, downstream from the Salt Creek and Elkhorn River inflows, indicated significant positive trends in most annual and all October–November low flows and August mean streamflow but insignificant trends in annual mean streamflow and June, July, and September monthly mean streamflows. Streamflow records for the Platte River near Duncan, Nebr. (USGS station 06774000), streamgage only indicated a significant trend in the August mean streamflow; no other metrics had significant trends at the streamgage. The trend analyses are sensitive to the period that is analyzed for trends. Sites with the most significant trends for low-flow metrics for the period 1961–2011 have fewer significant trends for low-flow metrics for the period after 1980–2011. The results indicate that positive trends in low flows at the Salt Creek and Elkhorn River streamgages may be contributing to positive trends in low flows for the Platte River at Louisville, Nebr., streamgage. Likewise, streamflow in the Salt Creek and Elkhorn River Basins may be contributing to the positive trend in August mean streamflow for the Platte River at Louisville, Nebr., streamgage, three lower Elkhorn River streamgages, and the Salt Creek streamgage. Precipitation was also examined as a primary cause for streamflow trends in the Elkhorn River Basin. For the four streamgages in the Elkhorn River Basin, relations between precipitation and streamflow were examined on an annual and monthly basis using linear regression. In general, the goodness of fit for the linear relations was poor with coefficient of determination values of less than or equal to 0.10 for four of the eight relations. Only one significant increase in annual precipitation upstream from the four streamgages and the frequent detection of significant increases in streamflow after removing the effect of precipitation indicate that other factors besides precipitation may have played a role in the significant positive trends in low-flow periods in the lower Elkhorn River and its tributaries.

Nebraska↗

Nonstationary flood frequency analysis using regression in the north-central United States

Traditional flood frequency methods assume that the statistical properties of peak streamflow do not change with time and may not be appropriate for many areas in the north-central United States. This study examines a nonstationary flood frequency analysis method that uses ordinary least squares linear regression to estimate flood magnitudes at U.S. Geological Survey streamgages that exhibit trends and change points in a nine-State region including Montana, North Dakota, South Dakota, Minnesota, Illinois, Iowa, Wisconsin, Missouri, and Michigan. Additionally, an extension of this method is introduced, which enables nonstationary flood frequency based on a statistical relation with a stochastic climate predictor. Estimates of the 1-percent annual exceedance probability flood using regression equations to adjust for conditions in 2020 were computed at U.S. Geological Survey streamgages across the study area. Regression equations used either a time index or a climate variable as the explanatory variable for changes in peak streamflow. Of 153 candidate streamgages, the assumptions of time-adjusted analyses were met at 137 streamgages. Climate-adjusted flood frequency analyses were applicable at 98 streamgages based on annual precipitation, annual temperature, or annual snowfall. Time- and climate-adjusted methods produced similar estimates of the 1-percent annual exceedance probability flood magnitude at streamgages where both methods were applicable. Nonstationary estimates of the 1-percent annual exceedance probability flood were primarily greater than stationary estimates in eastern North and South Dakota, Minnesota, Iowa, Illinois, and parts of Missouri and less than stationary estimates in Montana, western North and South Dakota, and Wisconsin. The largest differences between stationary and nonstationary flood estimates were in North and South Dakota and Minnesota.

Illinois, Iowa, Michigan, Minnesota, Missouri, Mon↗

Estimation of peak streamflows for unregulated rural streams in Kansas

Peak streamflows were estimated at selected recurrence intervals (frequencies) ranging from 2 to 200 years using log-Pearson Type III distributions for 253 streamflow-gaging stations in Kansas. The annual peak-streamflow data, through the 1997 water year, were from streamflow-gaging stations with unregulated flow in mostly rural basins. A weighted least-squares regression model was used to generalize the coefficients of station skewness. The resulting generalized skewness equation provides more reliable estimates than the previously developed equation for Kansas. A generalized least-squares regression model then was used to develop equations for estimating peak streamflows for sites without stream gages for selected frequencies from selected physical and climatic basin characteristics for sites without stream gages. The equations can be used to estimate peak streamflows for selected frequencies using contributing-drainage area, mean annual precipitation, soil permeability, and slope of the main channel for ungaged sites in Kansas with a contributing-drainage area greater than 0.17 and less than 9,100 square miles. The errors of prediction for the generalized least-squares-generated equations range from 31 to 62 percent.

Water-Resources Investigations Report↗

Map showing ground-water conditions in the Aravaipa Valley area, Graham and Pinal Counties, Arizona-1975

This hydrologic map of the Aravaipa Valley area includes about 500 sq mi in southeastern Arizona. Development of the ground-water resources is small, and pumpage is estimated to be less than 3,000 acre-ft annually for irrigation, livestock, and domestic uses. Hydrographs of the water level in selected wells show no long-term decline. Irrigation wells yield as much as 1 ,200 gal/min from the younger and older alluvium along Aravaipa Creek. The chemical quality of the ground water generally is good.

Arizona↗

Digital data sets of depth-duration frequency of precipitation for Oklahoma

These geospatial data sets were produced as part of a regional precipitation frequency analysis for Oklahoma. The data sets consist of surface grids of precipitation depths for seven frequencies (expressed as recurrence intervals of 2-, 5-, 10-, 25-, 50-, 100-, and 500-years) and 12 durations (15-, 30-, and 60-minutes; 1-, 2-, 3-, 6-, 12-, and 24-hours; and 1-, 3-, and 7-days). Eighty-four depth-duration-frequency surfaces were produced from precipitation-station data. Precipitation-station data from which the surfaces were interpolated and contour lines derived from each surface also are included. Contour intervals vary from 0.05 to 0.5 inch. Data were used from precipitation gage stations with at least 10 years of record within Oklahoma and a zone extending about 50 kilometers into bordering states. Three different rain gage networks provided the data (15-minute, 1-hour, and 1-day). Precipitation annual maxima (depths) were determined from the station data for each duration for 110 15-minute, 141 hourly, and 413 daily stations. Statistical methods were used to estimate precipitation depths for each duration-frequency at each station. These station depth-duration-frequency estimates were interpolated to produce continuous grids with grid-cell spacing of 2,000 meters. Contour lines derived from these surfaces (grids) were used to produce the maps in the 'Depth-Duration Frequency of Precipitation for Oklahoma,' by R.L. Tortorelli, Alan Rea, and W.H. Asquith, U.S. Geological Survey Water-Resources Investigations Report 99-4232. The geospatial data sets are presented in digital form for use with geographic information systems. These geospatial data sets may be used to determine an interpolated value of depth-duration-frequency of precipitation for any point in Oklahoma.

Oklahoma↗

Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2016–17

Stream stability, flood frequency, and streambed scour potential were evaluated at 20 Alaskan river- and stream-spanning bridges lacking a quantitative scour analysis or having unknown foundation details. Three of the bridges had been assessed shortly before the study described in this report but were re-assessed using different methods or data. Channel instability related to mining may affect scour at one site, while channel instability related to flow distribution changes can be seen at one site. One bridge was closed because of abutment scour prior to the study. Otherwise, channels generally showed stable bed elevations. Contraction and abutment scour were calculated for all 20 bridges, and pier scour was calculated for the 2 bridges that had piers. Vertical contraction (pressure flow) scour was calculated for one site at which the modeled water surface was higher than the superstructure of the bridge. Hydraulic variables for the scour calculations were derived from one-dimensional and two-dimensional hydraulic models of the 1- and 0.2-percent annual exceedance probability floods (also known as the 100- and 500-year floods, respectively). Scour also was calculated for large recorded floods at two sites. At many sites, overflow of road approaches relieves the bridge during floods and lessens the potential for scour. Two-dimensional hydraulic models are superior to one-dimensional hydraulic models at distributing flow between bridges, road approaches, and floodplains, and therefore likely produce more reasonable scour values at sites with substantial floodplain flow.

Alaska↗

Peak-flow variability, peak-flow informational needs, and consideration of regional regression analyses in managing the crest-stage gage network in Montana

The U.S. Geological Survey (USGS), in cooperation with the Montana Department of Transportation (MDT), has operated a crest-stage gage (CSG) network in Montana to collect peak-flow data since 1955. The CSG network is vital to collecting peak-flow data on small drainage basins that typically are not addressed by continuous streamflow operations. Discussions between USGS and MDT identified a need for evaluating the CSG network to allow for better decision making in the management of the network. The purpose of this report is to (1) generally describe peak-flow variability in Montana, (2) assess peak-flow informational needs relevant to MDT activities, and (3) consider the characteristics of the active CSG network in relation to addressing the informational needs. The evaluation of the CSG network is intended to assist in prioritization for discontinuation of CSGs and other activities involving changes to the CSG network. Peak-flow variability was investigated by analysis of selected peak-flow characteristics of 659 unregulated streamgages in or near Montana. A generalized peak-flow variability index ( PFVI ) was developed to provide large-scale representation of peak-flow variability in Montana. For unregulated Montana streamgages, PFVI generally monotonically decreases with increasing drainage area, although there is somewhat large (but generally consistent) variability about the locally weighted scatterplot smooth line. Presumably, highly variable small-scale hydroclimatic processes are integrated with increasing drainage area such that variability in many hydrologic characteristics is reduced. PFVI also decreases with increasing mean basin elevation and mean annual precipitation. Presumably, higher elevation and wetter hydroclimatic settings in Montana contribute to reduced variability in hydrologic characteristics. Intuitively, PFVI might be expected to generally decrease with increasing years of record because the standard deviation might typically be expected to decrease with increasing sample size. However, relations among PFVI and years of record are more complex and variable than drainage area, elevation, and precipitation. PFVI variably increases from 10 to about 40 years of record and then generally monotonically decreases from about 40 to about 105 years of record. Relations among PFVI and the years of record might be confounded by effects of drainage area because streamgages with long periods of record (greater than about 60 years) generally have large drainage areas (greater than about 100 square miles). The relations between PFVI and drainage area, mean basin elevation, mean annual precipitation, and years of record substantially differ among the eight hydrologic regions in Montana. As such, the PFVI relations were further investigated within each hydrologic region. A major use of peak-flow information by MDT is for design of road and highway infrastructure, including bridges, culverts, and roadside drainage ditches. As such, basin characteristics (including drainage area, mean basin elevation, and mean annual precipitation) of the Montana streamgage network (735 regulated and unregulated streamgages) were statistically investigated in relation to basin characteristics of 12,639 road and stream intersections in Montana. Both regulated and unregulated streamgages were investigated because the road and stream intersections are on both regulated and unregulated streams. Exploratory analyses indicated that the various relations substantially differ among the hydrologic regions. As such, the relations between the Montana streamgage network and the road and stream intersections were further investigated within each hydrologic region. An important objective of the CSG network is to provide data for developing regional regression equations (RREs) for estimating frequencies at ungaged sites in Montana. Various characteristics of the RREs substantially differ among the eight hydrologic regions in Montana. As such, the RRE characteristics were further investigated within each hydrologic region. For each of the eight hydrologic regions, various characteristics of peak-flow variability, peak-flow informational needs, and regional regression analyses were investigated in detail. Possible shortcomings of the streamgage network in each hydrologic region are identified and possible future improvements to the CSG network are presented.

Montana↗

The Ogden Valley artesian reservoir

Ogden Valley, in Weber County, Utah, contains an artesian reservoir from which the city of Ogden obtains all except a small part of its municipal water supply. A detailed investigation of the ground-water resources of Ogden Valley, and particularly of this artesian reservoir, was made by the Geological Survey, United States Department of the Interior, in cooperation with the city of Ogden between 1932 and 1934, and the results of this investigation have been reported by Leggette and Taylor. 1 The present paper, which might be termed a sequel to that report, is based on data collected during those years, augmented by records that have been obtained (1935-1940) by the Geological Survey as part of a State-wide project in cooperation with the Utah State Engineer. The conclusions drawn from the study of these records and presented in detail in the following pages are as follows: (1) The artesian reservoir is filled to capacity nearly every year during the spring run-off from melting snow; (2) after the annual freshet, the recharge to the reservoir is insufficient to balance the discharge from artesian wells, which ordinarily is at a maximum during the summer; the reservoir is depleted and is not filled again until the following spring; (3) during the periods when the artesian reservoir is not full the rate of recharge is more or less proportional to the inflow to the valley by streams, except that rain on the recharge area may be of sufficient intensity to contribute some water by infiltration and deep penetration; and (4) the artesian reservoir thus serves to store water that would otherwise be lost to Great Salt Lake in the excess spring overflow, and available records indicate that water used by increased draft from wells would be replenished in normal years by increased recharge during the spring freshet.

Utah↗

Water-resources appraisal of the Wet Mountain Valley, in parts of Custer and Fremont counties, Colorado

The Wet Mountain Valley is an intermontane trough filled to a depth of at least 6,700 feet with unconsolidated deposits. Ground water occurs under both artesian and water-table conditions within the basin-fill aquifer and ground-water moverment is toward Grape and Texas Creeks. The depth to the water table is less than 10 feet in an area of about 40 square miles along the central part of the valley and is less than 100 feet in most of the remainder of the valley. Ground water stored in the upper 200 feet of saturated basin-fill sediments is estimated to total 1.5 million acre-feet. Yields greater than 50 gallons per minute generally can be expected from wells in the central part of the basin-fill aquifer, and yields less than 50 gallons per minute are generally reported from wells around the edge of the basin-fill aquifer. Yields of wells in the mountainous areas are generally less than 20 gallons per minute. Most streamflow occurs as a result of snowmelt runoff during June and July. The long-term annual runoff at seven stations ranges from an estimated 0.02 cubic foot per second per square mile to an estimated 1.17 cubic feet per second per square mile, generaly increasing with station altitude. Generalized annyal water budgets for two areas in the Wet Mountain Valley indicate that surface-water outflow is only 7 to 11 percent of the total water supply from precipitation and other sources. The remaining water is lost to the atmosphere by evapotranspiration. The quality of both the surface and ground water is generally within the recommended limits for drinking water set by the U.S. Public Health Service. (Woodard-USGS)

Water-Resources Investigations Report↗

Water-quality characteristics in runoff for three discovery farms in North Dakota, 2008-12

The U.S. Geological Survey, in cooperation with North Dakota State University Agriculture Research Extension and in collaboration with North Dakota State Department of Health, North Dakota State Water Commission, U.S. Environmental Protection Agency, and several agricultural producers, helped organize a Discovery Farms program in North Dakota in 2007. Discharge measurements and water-quality samples collected at the three Farms (Underwood, Dazey, and Embden) were used to describe water-quality characteristics in runoff, and compute estimates of annual loads and yields for selected constituents from spring 2008 through fall 2012. Consistent patterns in water quality emerged at each individual farm, but similarities among farms also were observed. Suspended sediment, total phosphorus, and ammonia concentrations generally decreased downstream from feeding areas, and were primarily affected by surface runoff processes such as dilution, settling out of sediment, or vegetative uptake. Because surface runoff affects these constituents, increased annual surface runoff volume tended to result in increased loads and yields. No significant change in nitrate plus nitrite concentration were observed downstream from feeding areas because additional processes such as high solubility, nitrification, denitrification, and surface-groundwater interaction affect nitrate plus nitrite. For nitrate plus nitrite, increases in annual runoff volume did not consistently relate to increases in annual loads and yields. It seems that temporal distribution of precipitation and surface-groundwater interaction affected nitrate plus nitrite loads and yields. For surface drainage sites, the primary form of nitrogen was organic nitrogen whereas for subsurface drainage sites, the primary form of nitrogen was nitrate plus nitrite nitrogen.

North Dakota↗