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USGS2010

Status of groundwater levels and storage volume in the Equus Beds aquifer near Wichita, Kansas, January 2006 to January 2010

A part of the Equus Beds aquifer in southwestern Harvey County and northwestern Sedgwick County was developed to supply water to residents of Wichita and for irrigation in south-central Kansas. Groundwater pumping for city and agricultural use caused water levels to decline in a large part of the aquifer northwest of Wichita. In 1965, the city of Wichita began using water from Cheney Reservoir in addition to water from the Equus Beds aquifer to meet the city's increasing demand for water. Irrigation pumpage in the area increased substantially during the 1970s and 1980s and contributed to the water-level declines. Water-level declines reached their maximum to date in October 1992. Proposals to artificially recharge the aquifer have been made since the 1950s to meet future water-supply needs and to protect the aquifer from the intrusion of saltwater from sources to the south and west. In 2007, Wichita implemented Phase 1 of the Equus Beds Aquifer Storage and Recovery project for large-scale artificial recharge of the aquifer. A period of water-level rises associated with greater-than-average precipitation and decreased city pumpage from the area began in 1993 and continued through January 2010. During January 2010, the direction of ground-water flow in the Equus Beds aquifer in the area was generally from west to east, similar to the direction prior to development of the aquifer. Water-level changes since 1940 for the period January 2006 to January 2010 ranged from a decline of more than 30 feet to a rise of more than 4 feet. Almost all wells in the area had cumulative water-level rises from October 1992 (period of maximum storage loss) to January 2010 and from January 2007 (beginning of large-scale artificial recharge) to January 2010. The average cumulative water-level change from October 1992 to January 2010 was a rise of about 8.7 feet and from January 2007 to January 2010 was a rise of about 3.2 feet. The storage-volume change in the study area for the period October 1992 to January 2010 represented a recovery of about 183,000 acre-feet, or about 65 percent of the storage volume previously lost from August 1940 to October 1992, and was the largest recovery since October 1992 to date. Decreased city pumpage and artificial recharge during 1993-2009 and 2007-09 contributed to the recovery of storage volume in both periods, but artificial recharge's contribution was much smaller. Irrigation pumpage, because it increased during 1993-2009, did not contribute to the recovery of storage volume from October 1992 to January 2010. Recharge from excess precipitation contributed to the recovery of storage volume in both periods because precipitation averaged about 2 and 6 inches per year more than the annual long-term average of 31.52 inches during 1993-2009 and 2007-09, respectively. Sustainable yield for the Equus Beds aquifer in the study area was estimated to be about 57,000 acre-feet per year using two different methods. The sum of permitted annual irrigation (about 45,600 acre-feet) and city (about 31,400 acre-feet) pumpage of 77,000 acre-feet per year greatly exceeds the estimated sustainable yield. Effective water management, including additions to the water budget such as those from the Equus Beds Aquifer Storage and Recovery project, can help produce the most water for beneficial use in a more sustainable way.

Scientific Investigations Report↗
USGS2011

Peak-flow characteristics of Virginia streams

Peak-flow annual exceedance probabilities, also called probability-percent chance flow estimates, and regional regression equations are provided describing the peak-flow characteristics of Virginia streams. Statistical methods are used to evaluate peak-flow data. Analysis of Virginia peak-flow data collected from 1895 through 2007 is summarized. Methods are provided for estimating unregulated peak flow of gaged and ungaged streams. Station peak-flow characteristics identified by fitting the logarithms of annual peak flows to a Log Pearson Type III frequency distribution yield annual exceedance probabilities of 0.5, 0.4292, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 for 476 streamgaging stations. Stream basin characteristics computed using spatial data and a geographic information system are used as explanatory variables in regional regression model equations for six physiographic regions to estimate regional annual exceedance probabilities at gaged and ungaged sites. Weighted peak-flow values that combine annual exceedance probabilities computed from gaging station data and from regional regression equations provide improved peak-flow estimates. Text, figures, and lists are provided summarizing selected peak-flow sites, delineated physiographic regions, peak-flow estimates, basin characteristics, regional regression model equations, error estimates, definitions, data sources, and candidate regression model equations. This study supersedes previous studies of peak flows in Virginia.

Virginia↗
USGS1990

A conceptual weather-type classification procedure for the Philadelphia, Pennsylvania, area

A simple method of weather-type classification, based on a conceptual model of pressure systems that pass through the Philadelphia, Pennsylvania, area, has been developed. The only inputs required for the procedure are daily mean wind direction and cloud cover, which are used to index the relative position of pressure systems and fronts to Philadelphia. Daily mean wind-direction and cloud-cover data recorded at Philadelphia, Pennsylvania, from January 1954 through August 1988 were used to categorize daily weather conditions. The conceptual weather types reflect changes in daily air and dew-point temperatures, and changes in monthly mean temperature and monthly and annual precipitation. The weather-type classification produced by using the conceptual model was similar to a classification produced by using a multivariate statistical classification procedure. Even though the conceptual weather types are derived from a small amount of data, they appear to account for the variability of daily weather patterns sufficiently to describe distinct weather conditions for use in environmental analyses of weather-sensitive processes.

Pennsylvania↗
USGS2000

Environmental and hydrologic overview of the Yukon River basin, Alaska and Canada

The Yukon River, located in northwestern Canada and central Alaska, drains an area of more than 330,000 square miles, making it the fourth largest drainage basin in North America. Approximately 126,000 people live in this basin and 10 percent of these people maintain a subsistence lifestyle, depending on the basin’s fish and game resources. Twenty ecoregions compose the Yukon River Basin, which indicates the large diversity of natural features of the watershed, such as climate, soils, permafrost, and geology. Although the annual mean discharge of the Yukon River near its mouth is more than 200,000 cubic feet per second, most of the flow occurs in the summer months from snowmelt, rainfall, and glacial melt. Eight major rivers flow into the Yukon River. Two of these rivers, the Tanana River and the White River, are glacier-fed rivers and together account for 29 percent of the total water flow of the Yukon. Two others, the Porcupine River and the Koyukuk River, are underlain by continuous permafrost and drain larger areas than the Tanana and the White, but together contribute only 22 percent of the total water flow in the Yukon. At its mouth, the Yukon River transports about 60 million tons of suspended sediment annually into the Bering Sea. However, an estimated 20 million tons annually is deposited on flood plains and in braided reaches of the river. The waters of the main stem of the Yukon River and its tributaries are predominantly calcium magnesium bicarbonate waters with specific conductances generally less than 400 microsiemens per centimeter. Water quality of the Yukon River Basin varies temporally between summer and winter. Water quality also varies spatially among ecoregions.

Alaska, British Columbia↗
USGS2024

Water resources inventory of the Las Cienegas National Conservation Area, southeastern Arizona

The Las Cienegas National Conservation Area was established by the Las Cienegas National Conservation Area Establishment Act of 1999 (Public Law 106–538) and is managed by the Bureau of Land Management. Located in southeastern Arizona, the conservation area contains more than 45,000 acres of rolling grassland, wetlands, and woodlands surrounded by isolated mountain ranges that are part of the Madrean archipelago. This report describes the surface-water and groundwater resources within, and hydrologically connected to, the conservation area. Two primary aquifers have been identified within the Las Cienegas National Conservation Area: a Quaternary alluvial aquifer and a Miocene to Pliocene basin-fill aquifer. The Quaternary alluvial aquifer consists of Quaternary saturated stream alluvium along Cienega Creek and its major tributaries. This aquifer provides the water necessary for base flow in the perennial stream reaches that support aquatic life and for wetland and riparian habitat along the stream courses. Wells and piezometers completed in the Quaternary alluvial aquifer show both seasonal and daily water-level fluctuation patterns, as well as responses to flood flows in Cienega Creek. The basin-fill aquifer, in contrast, consists chiefly of Miocene to Pliocene alluvium within a sedimentary basin that is at least 4,800 feet deep. This aquifer is developed for anthropogenic uses more often than the Quaternary alluvial aquifer is developed. Generally, water levels in wells completed in the basin-fill aquifer have gradually declined a few feet between 2011, when measurements began, and 2022, when this report was written. Most water-chemistry samples available from the basin-fill aquifer had either a sodium-bicarbonate or calcium-bicarbonate water type. Previous research has shown that most recharge to the basin-fill aquifer likely comes from mountain-front and mountain-block recharge. Research further shows that this aquifer likely provides most of the recharge to the Quaternary alluvial aquifer. Because no production wells completed in bedrock exist within the conservation area, little is known about the hydraulic properties of the bedrock therein, but usable quantities of water can likely be produced from places where the bedrock has highly developed joint or fracture systems. During 2006–2021, the average combined length of measured perennial stream reaches within the main part of the Las Cienegas National Conservation Area was 6.35 miles. The average annual base flow of Cienega Creek during 2002–2021, estimated with the Standard Base-Flow Index method using data from a streamgage within the conservation area, was 0.62 cubic feet per second. Monthly mean streamflow measured at this streamgage for the same period ranged from a low of 0.29 cubic feet per second (in June) to a high of 9.8 cubic feet per second (in July). The July average is heavily influenced by a flood that occurred in July 2021; the median July streamflow for 2002–2021 is just 0.84 cubic feet per second. Periods with no daily flow are not uncommon at this gage during late May and June.

Arizona↗
USGS2025

An evaluation of the effects of different deicing salt application rates on three watersheds in Essex County, New York

The U.S. Geological Survey, in cooperation with the New York State Department of Transportation, evaluated the effects of different deicing salt application rates on surface water, groundwater, and highway runoff quality near State highways in northern New York. Three reaches of State highways were tested with different deicing treatments between October 2019 and November 2022: a salt-sand mixture (Treatment A), a salt mixture applied at a lower rate (Treatment B), and a control mixture consistent with typical deicing salt amounts and application rates. Data on pavement conditions and the quality of surface water, highway runoff, and groundwater were collected. Surface electromagnetic data were also collected. Surface-water and groundwater quality downgradient from the State highways were compared with water quality at upgradient locations. The percentage of snow or ice coverage was used to evaluate the effectiveness of the salt applications. This report provides an overview of the transport of deicing salt. The Treatment B watershed had deicing mixture applied more frequently than other highway reaches, which caused it to have the highest annual total chloride application. Despite differences in chloride application, flow-weighted mean chloride concentrations in highway runoff were comparable across treatments. Chloride concentrations were elevated in surface water and groundwater downgradient from highways relative to chloride concentrations upgradient from highways. A chloride mass balance, calculated for one treatment watershed, indicated that groundwater affected by legacy deicing practices may be contributing additional chloride to surface water. Spatial patterns from electromagnetic surveys show a shallow saline plume alongside the highway in that area. Differences in winter severity and pavement-surface conditions drove deicing salt applications in the treatment areas. This study found that several factors affect chloride loads in the watersheds, including variable winter conditions, adaptive snow and ice management, legacy management practices, and area-specific aquifer and groundwater conditions.

New York↗
USGS2025

Potential risks of vegetation treatments to introduce and increase invasive annual grasses in rangelands of Montana, North Dakota, and South Dakota— A science synthesis to inform National Environmental Policy Act analyses

The U.S. Geological Survey is working with Federal land management agencies to develop a series of planned structured science syntheses to support environmental effects analyses that agencies conduct under the National Environmental Policy Act (NEPA). This report synthesizes science information relevant to environmental effects analyses concerned with potential increases in the distribution and abundance of invasive annual grasses (IAGs) from proposed vegetation treatments for habitat restoration. The focal environments for this synthesis are rangelands in the intermontane valleys of Montana and the northern Great Plains of Montana, North Dakota, and South Dakota. The synthesis is organized to align with the standard elements of NEPA analyses and provides information on relevant scientific studies, data availability, analysis methods, and mitigation measures. We found that the likelihood of increasing IAGs from vegetation treatments depends on treatment type and environmental context. In sagebrush ecosystems of the focal region, prescribed fire often reduces or does not increase IAGs. Treatments that cause soil disturbances, such as mechanical removals of sagebrush or firebreak constructions, are more likely to increase IAGs than other treatments. Herbicides applied to reduce sagebrush cover have not increased the proportion of IAGs in the plant community. Temperature and precipitation have been strong factors in determining IAG responses to vegetation treatments in sagebrush ecosystems of the focal region, where more precipitation in spring and summer likely provides a competitive edge to native, perennial grasses more than winter annual grasses like Bromus tectorum L. (cheatgrass). In grasslands, prescribed fire often reduces IAGs, but effects depend on the abundance of native species and are often short lived. Mowing can increase or decrease IAGs in grassland ecosystems. Grassland site conditions, such as southeast-facing slopes, sandier or rockier sites, or lower native species cover or richness affect the likelihood of invasion by annual grasses. Maintaining adequate cover of perennial vegetation creates rangelands that are resistant and resilient to annual grass invasions. Managers can minimize invasion potential by focusing on treatment type, placement, and seasonal timing. Herbicides also can provide effective mitigation, especially in combination with other controls such as prescribed fire or grazing. This report can be incorporated by reference in NEPA documentation, included in a project record, or provide a general reference for understanding and identifying literature about increases in IAGs associated with vegetation treatments in rangelands in this focal region.

Montana, North Dakota, South Dakota↗
USGS2009

Hydrologic Conditions in Florida during Water Year 2007

Record-high and record-low hydrologic conditions occurred during water year 2007 (October 1, 2006 - September 30, 2007) based on analyses of precipitation, surface-water flows, lake elevations, and ground-water levels. For example, the streamgage at Suwannee River at White Springs in northwest Florida recorded an annual streamflow of 103 cubic feet per second during 2007, or about 6 percent of the period-of-record average since monitoring began in 1906. Lake Okeechobee in south Florida reached record-low elevations (8.82 feet on July 2) since monitoring began in 1912. Several wells throughout the State registered period-of-record lowest daily maximum water levels.

Scientific Investigations Report↗
USGS2009

Relation Between Flow and Dissolved Oxygen in the Roanoke River Between Roanoke Rapids and Jamesville, North Carolina, 1998-2005

Understanding the relation between dam release characteristics and downstream water quality in the lower Roanoke River, North Carolina, is important for natural-resource management and ecosystem protection. Data from four raingages, four water-quality monitoring sites, and one streamflow-measurement site were used to identify statistical relations and discernible quantitative or qualitative patterns linking Roanoke River instream dissolved-oxygen (DO) levels to releases at Roanoke Rapids Dam for the period 1998-2005. The time-series DO data, complicated by the occurrence of major hurricanes in the short period of hourly DO data collection at the dam, present a mixed picture of the effects of hydropower peaking (a technique used by hydropower dam operators to produce electricity when consumption is high by passing a large volume of water through the dam turbines, which dramatically increases the volume of flow below the dam) on downstream DO. Other than in 2003 when dissolved-oxygen concentrations in the Roanoke River were likely affected by runoff from Hurricane Isabel rains, there were not consistent, statistically significant differences detected in the annual medians of hourly and(or) daily DO values during peaking versus nonpeaking periods. Along the Roanoke River, downstream of Roanoke Rapids Dam at Oak City, North Carolina, using a 95-percent confidence interval, the median value of the May-November daily mean DO concentrations for each year was lower during peaking periods for 2 years, higher for 2 years, and not significantly different for 4 years. Downstream at Jamesville, North Carolina, also using a 95-percent confidence interval, the median value of the annual May-November daily mean DO concentrations during hydropower peaking was lower for 4 years, higher for 2 years, and not significantly different for 2 years. In summary, the effect of hydropower peaking on downstream DO was inconsistent. Conversely, large precipitation events downstream from the dam resulted in consistent, statistically significant decreases in DO in the mainstem of the Roanoke River at Oak City and Jamesville.

North Carolina↗
USGS2004

Evaluation of ground-water contribution to streamflow in coastal Georgia and adjacent parts of Florida and South Carolina

Stream-aquifer relations in the coastal area of Georgia and adjacent parts of Florida and South Carolina were evaluated as part of the Coastal Georgia Sound Science Initiative, the Georgia Environmental Protection Division's strategy to protect the Upper Floridan aquifer from saltwater intrusion. Ground-water discharge to streams was estimated using three methods: hydrograph separation, drought-streamflow measurements, and linear-regression analysis of streamflow duration. Ground-water discharge during the drought years of 1954, 1981, and 2000 was analyzed for minimum ground-water contribution to streamflow. Hydrograph separation was used to estimate baseflow at eight streamflow gaging stations during the 31-year period 1971?2001. Six additional streamflow gaging stations were evaluated using linear-regression analysis of flow duration to determine mean annual baseflow. The study area centers on three major river systems ? the Salkehatchie?Savannah?Ogeechee, Altamaha?Satilla?St Marys, and Suwannee ? that interact with the underlying ground-water system to varying degrees, largely based on the degree of incision of the river into the aquifer and on the topography. Results presented in this report are being used to calibrate a regional ground-water flow model to evaluate ground-water flow and stream-aquifer relations of the Upper Floridan aquifer. Hydrograph separation indicated decreased baseflow to streams during drought periods as water levels declined in the aquifer. Average mean annual baseflow ranged from 39 to 74 percent of mean annual streamflow, with a mean contribution of 58 percent for the period 1971?2001. In a wet year (1997), baseflow composed from 33 to 70 percent of mean annual streamflow. Drought-streamflow analysis estimated baseflow contribution to streamflow ranged from 0 to 24 percent of mean annual streamflow. Linear-regression analysis of streamflow duration estimated the Q35 (flow that is equaled or exceeded 35 percent of the time) as the most reasonable estimate of baseflow. The Q35, when compared to mean annual streamflow, estimated a baseflow contribution ranging from 65 to 102 percent of streamflow. The Q35 estimate tends to overestimate baseflow as evidenced by the baseflow contribution greater than 100 percent. Ground-water contributions to streamflow are greatest during winter when evapotranspiration is low, and least during summer when evapotranspiration is high. Baseflow accounted for a larger percentage of streamflow at gaging stations in the Salkehatchie?Savannah?Ogeechee River Basin than in the other two basins. This difference is due largely to the availability of data, proximity to the Piedmont physiographic province where the major rivers originate and are by supplied ground water, and proximity to the upper Coastal Plain where there is greater topographic relief and interconnection between streams and aquifers.

Florida, Georgia, South Carolina↗
USGS2008

Salinity trends in the upper Colorado River basin upstream from the Grand Valley Salinity Control Unit, Colorado, 1986-2003

In 1974, the Colorado River Basin Salinity Control Act was passed into law. This law was enacted to address concerns regarding the salinity content of the Colorado River. The law authorized various construction projects in selected areas or "units" of the Colorado River Basin intended to reduce the salinity load in the Colorado River. One such area was the Grand Valley Salinity Control Unit in western Colorado. The U. S. Geological Survey has done extensive studies and research in the Grand Valley Salinity Control Unit that provide information to aid the U.S. Bureau of Reclamation and the Natural Resources Conservation Service in determining where salinity-control work may provide the best results, and to what extent salinity-control work was effective in reducing salinity concentrations and loads in the Colorado River. Previous studies have indicated that salinity concentrations and loads have been decreasing downstream from the Grand Valley Salinity Control Unit, and that the decreases are likely the result of salinity control work in these areas. Several of these reports; however, also document decreasing salinity loads upstream from the Grand Valley Salinity Control Unit. This finding was important because only a small amount of salinity-control work was being done in areas upstream from the Grand Valley Salinity Control Unit at the time the findings were reported (late 1990’s). As a result of those previous findings, the U.S. Bureau of Reclamation entered into a cooperative agreement with the U.S. Geological Survey to investigate salinity trends in selected areas bracketing the Grand Valley Salinity Control Unit and regions upstream from the Grand Valley Salinity Control Unit. The results of the study indicate that salinity loads were decreasing upstream from the Grand Valley Salinity Control Unit from 1986 through 2003, but the rates of decrease have slowed during the last 10 years. The average rate of decrease in salinity load upstream from the Grand Valley Salinity Control Unit was 10,700 tons/year. This accounts for approximately 27 percent of the decrease observed downstream from the Grand Valley Salinity Control Unit. Salinity loads were decreasing at the fastest rate (6,950 tons/year) in Region 4, which drains an area between the Colorado River at Cameo, Colorado (station CAMEO) and Colorado River above Glenwood Springs, Colorado (station GLEN) streamflow-gaging stations. Trends in salinity concentration and streamflow were tested at station CAMEO to determine if salinity concentration, streamflow, or both are controlling salinity loads upstream from the Grand Valley Salinity Control Unit. Trend tests of individual ion concentrations were included as potential indicators of what sources (based on mineral composition) may be controlling trends in the upper Colorado. No significant trend was detected for streamflow from 1986 to 2003 at station CAMEO; however, a significant downward trend was detected for salinity concentration. The trend slope indicates that salinity concentration is decreasing at a median rate of about 3.54 milligrams per liter per year. Five major ions (calcium, magnesium, sodium, sulfate, and chloride) were tested for trends. The results indicate that processes within source areas with rock and soil types (or other unidentified sources) bearing calcium, sodium, and sulfate had the largest effect on the downward trend in salinity load upstream from station CAMEO. Downward trends in salinity load resulting from ground-water sources and/or land-use change were thought to be possible reasons for the observed decreases in salinity loads; however, the cause or causes of the decreasing salinity loads are not fully understood. A reduction in the amount of ground-water percolation from Region 4 (resulting from work done through Federal irrigation system improvement programs as well as privately funded irrigation system improvements) has helped reduce annual salinity load from Region 4 by approximately 7,400 tons. This amount is equal to about 5.9 percent of the total decrease (125,000 tons, or about 6,950 tons/year) estimated to have occurred in Region 4 during water years 1986 through 2003. A geographic information system was used to quantify the change in the amount of irrigated land upstream from the Grand Valley Salinity Control Unit from 1993 through 2000. These data indicated that the amount of irrigated land did not change substantially, thus indicating that the downward trends in salinity load did not result from land-use change.

Colorado↗
USGS1996

Techniques to estimate generalized skew coefficients of annual peak streamflow for natural basins in Texas

This report presents two techniques to estimate generalized skew coefficients used for log-Pearson Type III peak-streamflow frequency analysis of natural basins in Texas. A natural basin has less than 10 percent impervious cover, and less than 10 percent of its drainage area is controlled by reservoirs. The estimation of generalized skew coefficients is based on annual peak and historical peak streamflow for all U.S. Geological Survey streamflow-gaging stations having at least 20 years of annual peak-streamflow record from natural basins in Texas. Station skew coefficients calculated for each of 255 Texas stations were used to estimate generalized skew coefficients for Texas. One technique to estimate generalized skew coefficients involved the use of regression equations developed for each of eight regions in Texas, and the other involved development of a statewide map of generalized skew coefficients. The weighted mean of the weighted mean standard errors of the regression equations for the eight regions is 0.36 log 10 skew units, and the weighted mean standard error of the map is 0.35 log 10 skew units. The technique based on the map is preferred for estimating generalized skew coefficients because of its smooth transition from one region of the State to another.

Texas↗
USGS2008

Climate simulation and flood risk analysis for 2008-40 for Devils Lake, North Dakota

Devils Lake and Stump Lake in northeastern North Dakota receive surface runoff from a 3,810-square-mile drainage basin, and evaporation provides the only major water loss unless the lakes are above their natural spill elevation to the Sheyenne River. In September 2007, flow from Devils Lake to Stump Lake had filled Stump Lake and the two lakes consisted of essentially one water body with an elevation of 1,447.1 feet, about 3 feet below the existing base flood elevation (1,450 feet) and about 12 feet below the natural outlet elevation to the Sheyenne River (1,459 feet). Devils Lake could continue to rise, causing extensive additional flood damages in the basin and, in the event of an uncontrolled natural spill, downstream in the Red River of the North Basin. This report describes the results of a study conducted by the U.S. Geological Survey, in cooperation with the Federal Emergency Management Agency, to evaluate future flood risk for Devils Lake and provide information for developing updated flood-insurance rate maps and planning flood-mitigation activities such as raising levees or roads. In about 1980, a large, abrupt, and highly significant increase in precipitation occurred in the Devils Lake Basin and elsewhere in the Northern Great Plains, and wetter-than-normal conditions have persisted through the present (2007). Although future precipitation is impossible to predict, paleoclimatic evidence and recent research on climate dynamics indicate the current wet conditions are not likely to end anytime soon. For example, there is about a 72-percent chance wet conditions will last at least 10 more years and about a 37-percent chance wet conditions will last at least 30 more years. A stochastic simulation model for Devils Lake and Stump Lake developed in a previous study was updated and used to generate 10,000 potential future realizations, or traces, of precipitation, evaporation, inflow, and lake levels given existing conditions on September 30, 2007, and randomly generated future duration of the current wet period. On the basis of the simulations, and assuming ice-free conditions and calm wind, the Devils Lake flood elevation for an annualized flood risk of 1 percent (analogous to a “100-year” riverine flood) was estimated to be 1,454.6 feet for a 10-year time horizon (2008­­­–17). Therefore, without adjusting for wind or ice, a residence near Devils Lake at elevation 1,454.6 feet has the same chance of being flooded sometime during the next 10 years as a residence at the edge of the 100-year flood plain along a river. Adjusting for the effects of wind or ice, which will increase the flood elevations for many locations near the lakes, was not within the scope of this study.

North Dakota↗
USGS2010

Dissolved-Solids Load in Henrys Fork Upstream from the Confluence with Antelope Wash, Wyoming, Water Years 1970-2009

Annual dissolved-solids load at the mouth of Henrys Fork was estimated by using data from U.S. Geological Survey streamflow-gaging station 09229500, Henrys Fork near Manila, Utah. The annual dissolved-solids load for water years 1970-2009 ranged from 18,300 tons in 1977 to 123,300 tons in 1983. Annual streamflows for this period ranged from 14,100 acre-feet in 1977 to 197,500 acre-feet in 1983. The 25-percent trimmed mean dissolved-solids load for water years 1970-2009 was 44,300 tons per year at Henrys Fork near Manila, Utah. Previous simulations using a SPAtially Referenced Regression On Watershed attributes (SPARROW) model for dissolved solids specific to water year 1991 conditions in the Upper Colorado River Basin predicted an annual dissolved-solids load of 25,000 tons for the Henrys Fork Basin upstream from Antelope Wash. On the basis of computed dissolved-solids load data from Henrys Fork near Manila, Utah, together with estimated annual dissolved-solids load from Antelope Wash and Peoples Canal, this prediction was adjusted to 37,200 tons. As determined by simulations with the Upper Colorado River Basin SPARROW model, approximately 56 percent (14,000 tons per year) of the dissolved-solids load at Henrys Fork upstream from Antelope Wash is associated with the 21,500 acres of irrigated agricultural lands in the upper Henrys Fork Basin.

Scientific Investigations Report↗
USGS2024

Assessment and characterization of ephemeral stream channel stability and mechanisms affecting erosion in Grand Valley, western Colorado, 2018–21

The Grand Valley in western Colorado is in the semiarid Southwest United States. The north side of the Grand Valley has many ungaged ephemeral streams, which are of particular interest because (1) the underlying bedrock geology, Late Cretaceous Mancos Shale, is a sedimentary rock deposit identified as a major salinity contributor to the Colorado River and (2) despite infrequent streamflows of short duration, monsoon-derived floods in these ephemeral streams can carry substantial amounts of sediment downstream, affecting upstream and downstream banks and channel cross sections. The study area is of interest, because salinity, or the total dissolved solids concentration, in the Colorado River causes an estimated $300 million to $400 million per year in economic damages in the United States, and it is estimated 62 percent of the Upper Colorado River Basin’s total dissolved solid loads originate from geologic sources. In an effort to minimize salt contributions to the Colorado River from public lands administered by the Bureau of Land Management, a comprehensive salinity control approach is typically used to reduce nonpoint sources of salinity through land management techniques and practices. In 2018, the U.S. Geological Survey, in cooperation with the Bureau of Land Management, began an assessment of ephemeral streams located on the north side of the Grand Valley, western Colorado, to characterize stream channel stability and identify mechanisms affecting erosion. The U.S. Geological Survey developed a method for automatically extracting channel cross-section geometry from existing remotely sensed terrain models. Based on estimated flood stage and surrogate streamflows, hydraulic characteristics were calculated. Furthermore, the channel geometries and hydraulic characteristics were used to estimate channel stability using a statistical model. Cross-section stabilities were determined from a stream channel stability assessment for a subset of 1,406 visited (field observed) locations out of 13,415 cross sections, which were delineated from remotely sensed terrain models. The application of Manning’s resistance equation in combination with multiple logistic regression models demonstrated channel stability can be estimated with a 0.845 goodness of fit for a validation dataset when using a combination of drainage area, width-to-depth ratio, sinuosity, and shear stress as the explanatory variables. Stream channel stability was extrapolated for 13,415 unvisited (not field observed) cross sections using the multiple logistic regression model and defined explanatory variables. Mapping of the ephemeral streams and their associated stabilities may be used by the Bureau of Land Management to prioritize areas for remediation or changes in management strategies to reduce sediment and salinity loading to the Colorado River. The study found channel stability within the ephemeral streams to be spatially variable, longitudinally discontinuous, and dictated by changes in channel bed slope. The stable ephemeral streams were relatively wide and shallow and often had smaller drainage areas with less potential for producing shear stresses capable of overcoming channel adhesion. A change in channel bed slope can provide the means necessary to generate shear stresses appropriate to initiate erosion and a subsequent stability transition to incising channels. Channel widening happens when either or both banks of an incising channel reach a critical height for mass wasting, or when channel curvature causes higher sidewall stress. Regardless, widening channels can promote increases in sinuosity and subsequently reduce steep channel bed slopes. Consequently, stable and widening channels can have comparable bed slopes, making channel bed slope a poor explanatory variable to predict channel stability overall, despite its function to initiate channel instability. The results were based on a surrogate 0.10 annual exceedance probability (AEP; return period equal to the 10-year flood) interval streamflow, although it was recognized fluctuations in streamflow would also affect channel stability. Past and current changes within the study area affect streamflow; therefore, mechanisms affecting erosion include land use disturbances, soil compaction, loss of vegetation cover, drought, less frequent and more extreme precipitation, and fires—which all intensify the potential runoff and erosion within the study area.

Colorado↗
USGS2000

Nutrients and suspended sediment in snowmelt runoff from part of the Upper Mississippi River Basin, Minnesota and Wisconsin, 1997

The U.S. Geological Survey sampled snowmelt runoff from 42 stream sites during March and April 1997 in part of the Upper Mississippi River Basin, Minnesota and Wisconsin, to characterize nutrient and suspended-sediment concentrations, yields, and loads. Ancillary data from 12 sites provided data to estimate constituent loads delivered during snowmelt and 1997. The snowmelt period contributed from 1 to 50 percent of 1997 annual loads of total nitrogen, total phosphorus, and suspended sediment at small stream sites, and 17 to 70 percent of annual loads at mainstem river sites. Small streams in agricultural areas transported the greatest proportions of annual loads during snowmelt. Snowmelt from urban streams transported the least proportions of annual loads. Agricultural streams had significantly greater median yields (p < 0.025) of dissolved nitrite, nitrate, phosphorus, orthophosphate, total nitrogen, and total phosphorus than forested sites, and significantly greater median yields (p < 0.025) of dissolved nitrate and orthophosphate than all other land uses. In forested areas, yields of suspended sediment and all nutrient forms were significantly greater (p < 0.05) for streams draining impermeable deposits than permeable deposits.

Minnesota, Wisconsin↗
USGS1979

Drinking-water quality and variations in water levels in the fractured crystalline-rock aquifer, west-central Jefferson County, Colorado

In parts of Jefferson County, CO, water for domestic use from the fractured crystalline-rock aquifer contained excessive concentrations of major ions, coliform bacteria, trace elements, or radiochemicals. Based on results of analyses from 26 wells, water from 21 of the wells contained excessive concentrations of one or more constituents. Drinking water standards were exceeded for fluoride in water from 2 wells, nitrate plus nitrite in 2 wells, dissolved solids in 1 well, iron in 6 wells, manganese in 8 wells, zinc in 2 wells, coliform bacteria in 4 wells, gross alpha radiation in 11 wells and possibly 4 more, and gross beta radiation possibly in 1 well. Local variations in concentrations of 15 chemical constituents, specific conductance, and water temperature were statistically significant. Specific conductance increased significantly during 1973-75 only in the vicinity of Indian Hills. Annual range in depths to water in 11 observation wells varied from 1 to 15 feet. The shallowest water levels were recorded in late winter, usually in February. The deepest water levels occurred during summer or fall, depending on the well and the year. Three-year trends in water level changes in 6 of the 11 wells indicated decreasing water storage in the aquifer. (USGS).

Water-Resources Investigations Report↗
USGS1986

Analysis of fixed-station water-quality data in the Umpqua River basin, Oregon

An appraisal of surface water quality in the Umpqua River basin was made using existing monthly data collected by the Oregon Department of Environmental Quality and the U.S. Geological Survey in cooperation with the Douglas County Water Resources Survey. This appraisal was limited to interpretation of instantaneous monthly water quality data collected in the Umpqua River basin from water years 1974 to 1983. These data were used to compare water quality conditions throughout the basin and to determine if data collected from the NASQAN (National Stream Quality Accounting network) station are representative of upstream basin conditions. In general, data collected at the NASQAN station represent a composite of water quality from the North and South Umpqua Rivers. These river basins account for 82 % of the NASQAN station drainage. Water quality concentrations, loads, yields, and trends were statistically described and related to point source effluent loads and basin characteristics including geohydrology, hydrology, population, land use, and water use. Available point-and nonpoint-source data provided minimal information for determining cause-effect relations and for explaining observed trends in water quality; however, the data did indicate that the largest effluent discharges are located in the South Umpqua River basin in the Roseburg-Winston area. Instantaneous and annual flow weighted levels of specific conductance, phosphorus, organic plus ammonia nitrogen, nitrite plus nitrate, and fecal coliform bacteria are generally highest in the South Umpqua River near Roseburg. These high levels generally occur during the summer months when river flow is extremely low relative to flow in the North Umpqua River. The North Umpqua River has among the lowest constituent concentrations observed in the basin. (Lantz-PTT)

Water-Resources Investigations Report↗