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Techniques for estimating magnitude and frequency of floods for Wisconsin streams

This report provides improved methods for estimating the magnitude and frequency of floods for Wisconsin streams. Proper design of hydraulic structures and adequate flood-plain management depend on this information. Multiple-regression techniques were used to develop equations for estimating flood frequencies at ungaged sites. The State is divided into five areas and has equations developed for each area. These areas are based on areal factors determined from previous studies and physical basin characteristics. Significant characteristics in the equations are soil permeability, drainage area, slope, storage, forest cover, snowfall, precipitation intensity, and mean annual precipitation. Standard errors of estimate for the regression equations ranged from 23 to 38 percent. Annual flood peaks, basin characteristics, and flood-frequency values are presented in this report. Data from 184 gaging stations were used in the regression analysis, of which 20 had rainfall-runoff data collected. Long-term synthetic peaks were generated from the rainfall-runoff data and were weighted with the observed peak data to improve the flood-frequency distributions. A method to estimate flood-frequency values for regulated streams was developed by discharge-drainage area relationships. Graphs for the major regulated streams are presented in the report.

Wisconsin↗

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↗

Flood peaks and discharge summaries in the Delaware River basin

Streamflow data from 299 continuous and crest-stage sites in the Delaware River basin are summarized in this report. The location, drainage area, period of record, type of gage, and average discharge for each gaging site are given. Also included are tables of annual peaks and peaks above base, annual and monthly means, and annual and monthly runoff.

Delaware, Maryland, New Jersey, New York, Pennsylv↗

Water resources of Monroe County, New York, water years 1997-99, with emphasis on water quality in the Irondequoit Creek basin—Atmospheric deposition, ground water, streamflow, trends in water quality, and chemical loads to Irondequoit Bay

Irondequoit Creek drains 169 square miles in the eastern part of Monroe County. Over time, nutrients transported by Irondequoit Creek to Irondequoit Bay on Lake Ontario have contributed to the eutrophication of the bay. Sewage-treatment-plant effluent, a major source of nutrients to the creek and its tributaries, was eliminated from the basin in 1979 by diversion to a regional wastewater-treatment facility, but sediment and contaminants from nonpoint sources continue to enter the creek and Irondequoit Bay. This report, the fourth in a series of reports that present interpretive analyses of the hydrologic data collected in Monroe County since 1984, interprets data from four surface-water monitoring sites in the Irondequoit Creek basin—Irondequoit Creek at Railroad Mills, East Branch Allen Creek at Pittsford, Allen Creek near Rochester, and Irondequoit Creek at Blossom Road. It also interprets data from three sites in the the Genesee River basin—Oatka Creek at Garbutt, Honeoye Creek at Honeoye Falls, and Black Creek at Churchville—as well as the Genesee River at Charlotte Pump Station, and also from a site on Northrup Creek at North Greece. The Northrup Creek site drains a 23.5-square-mile basin in western Monroe County, and provides information on surface-water quality in streams west of the Genesee River and on loads of nutrients delivered to Long Pond, a small eutrophic embayment of Lake Ontario. The report also includes water-level and water-quality data from nine observation wells in Ellison Park, and atmospheric-deposition data from a collection site at Mendon Ponds County Park. Average annual loads of some chemical constituents in atmospheric deposition for 1997–99 differed considerably from those for the long-term period 1984–96. Ammonia and potassium loads for 1997-99 were 144 and 118 percent greater, respectively, than for the previous period. Sodium and ammonia + organic nitrogen loads were 87 and 60 percent greater, respectively. Average annual loads of sulfate and orthophosphate for 1997-99 were 36 and 30 percent lower, respectively, than for the previous period. Loads of all nutrients deposited on the Irondequoit basin from atmospheric sources during 1997–99 greatly exceeded those transported by Irondequoit Creek. The ammonia load deposited on the basin was 139 times the load transported at Blossom Road (the most downstream site); the ammonia + organic nitrogen load was 6.3 times greater, orthophosphate 7.5 times greater, total phosphorus 1.3 times greater and nitrite + nitrate 1.5 times greater. Average yields of dissolved chloride and dissolved sulfate from atmospheric sources were much smaller than those transported by streamflow at Blossom Road.chloride was about 2 percent and sulfate about 8 percent of the amount transported. Trends in concentration of chemical constituents in surface water generally can be attributed to changes in land use, annual and seasonal variations in streamflow, and annual variations in the application of road salt to county highways and roads. Concentrations of several constituents in streams of the Irondequoit Creek basin showed statistically significant (α=0.05) trends from the beginning of their period of record through 1999. The constituent with the greatest number of significant trends was ammonia + organic nitrogen, with downward trends ranging from 4.1 to 5.6 percent per year at Allen Creek, Irondequoit Creek at Blossom Road, and East Branch Allen Creek. Orthophosphate showed an upward trend of 4.1 percent per year at Irondequoit Creek at Railroad Mills (the most upstream site). Dissolved chloride showed upward trends at Railroad Mills, Allen Creek, and Blossom Road. No trends in volatile suspended solids were noted at any of the four Irondequoit basin sites. Northrup Creek showed significant downward trends in concentrations of ammonia + organic nitrogen (3.3 percent per year), total phosphorus (3.4 percent per year), and orthophosphate (5.5 percent per year), and an upward trend for dissolved sulfate (1.8 percent per year). The Genesee River at Charlotte Pump Station showed downward trends of 6.1 percent per year for ammonia + organic nitrogen and 0.1 percent per year for chloride, and upward trends of 1.7 percent per year for total phosphorus and 6.6 percent per year for orthophosphate. Mean annual yields (mass per unit area) of most constituents at the Irondequoit Creek basin sites were similar to those noted for the previous report period (1994–96). East Branch Allen Creek showed lower yields of all constituents during 1997–99 than previously, even though runoff during 1997–99 was greater. These lower yields are attributed to the construction of an upstream detention basin on East Branch Allen Creek in 1995. Statistical analysis of long-term (greater than 12 years) streamflow records for unregulated streams in Monroe County indicated that annual mean flows for water years 1997–99 were in the normal range (75th to 25th percentile), although Allen Creek continues to show a significant downward trend in mean monthly streamflow during the 1984–99 water years.

New York↗

Stormwater quantity and quality in selected urban watersheds in Hampton Roads, Virginia, 2016–2020

Urbanization can substantially alter sediment and nutrient loadings to streams. Although a growing body of literature has documented these processes, conditions may vary widely by region and physiographic province (PP). Substantial investments are made by localities to meet federal, state, and local water-quality goals and locally relevant monitoring data are needed to appropriately set standards and track progress. In 2016, a long-term stormwater monitoring program was initiated to characterize water-quality and streamflow conditions and compute average annual nutrient- and sediment-loading rates across the three dominant land-use types—commercial (COM), high-density residential, and single-family residential (SFR)—in the Hampton Roads metropolitan region within the Coastal Plain PP in southeastern Virginia. This report summarizes the first five years of data collection to (1) assess patterns in streamflow and water chemistry across the three major land-use types in the region; (2) compute annual sediment and nutrient loads; and (3) compare annual loading rates to those in other urbanized regions. Patterns in watershed hydrology characteristics and conditions were similar to those observed in other urban monitoring studies. Base-flow indices were lower and stream flashiness indices were higher in the study watersheds compared to those in less developed reference watersheds. These patterns reflect a decrease in infiltration and consequent increase in storm runoff as a result of urbanization. Stream flashiness was strongly positively related to degree of impervious land cover and negatively to watershed area. Hydrologic metrics varied across the land-use gradient, reflecting greater and more rapid runoff in the COM watersheds than in SFR watersheds. Event-based analyses conducted exclusively on periods of runoff highlight longer duration events, longer time-to-peak streamflow, and a longer lag between peak precipitation and peak streamflow in SFR watersheds, and higher stormflow yields, runoff ratios, and peak flows in COM watersheds. Event-based metrics varied seasonally because of regional meteorological patterns. Concentrations of total suspended solids (TSS) and total phosphorus (TP) were positively correlated to streamflow, whereas concentrations of total nitrogen (TN) varied little across the hydrologic regime. Phosphorus composition varied spatially and seasonally—the proportion of orthophosphate (PO 4 3- ) was highest in samples collected from stations draining residential land-use types and was elevated in summer and fall. Nitrogen composition varied with hydrologic condition: nitrate plus nitrite (NO 3 - ) dominance during base flow shifted to total organic nitrogen (TON) dominance during periods of runoff. For all three major constituents (TSS, TP, and TN), concentrations were highest in SFR watersheds, whereas yields were greatest in COM watersheds. This seeming contradiction in concentration and yield across land-use types occurred because of spatial differences in streamflow yield. The network average TSS yield in Hampton Roads was lower than that in comparable networks in Fairfax County, Virginia, and Gwinnett County, Georgia, a difference that may reflect dissimilarities in the topographic and soil characteristics of the Coastal Plain versus those in Piedmont PPs, as well as differences in engineered concrete stormwater conveyances versus earthen streams. The average annual TP yield in Hampton Roads was higher than averages reported in comparison studies and was primarily driven by elevated PO 4 3- . Elevated PO 4 3- yields may be related to unique soil and geological features of the Coastal Plain PP that limit phosphorus retention. Total nitrogen yields in the Hampton Roads and Fairfax County networks were similar; however, composition did vary, with greater total organic nitrogen yields in Hampton Roads and greater NO 3 - yields in Fairfax County. Cross-correlation analyses and mass-volume curves were used to assess the timing of sediment and nutrient loadings. The majority of TSS and TP was typically transported during the initial phase of a storm-runoff event, a phenomenon commonly termed the “first flush.” Although TN concentrations typically peaked within an hour of peak streamflow, reflecting the particulate dominance of TN during stormflows, and loadings were greater during the early phase of most storm events, the stricter first-flush criterion was rarely met. This suggests that the most abundant sources of TN in these watersheds are not as directly connected to the stormwater-conveyance system as are TSS and TP.

Virginia↗

Simulation of groundwater and surface-water resources and evaluation of water-management alternatives for the Chamokane Creek basin, Stevens County, Washington

A three-dimensional, transient numerical model of groundwater and surface-water flow was constructed for Chamokane Creek basin to better understand the groundwater-flow system and its relation to surface-water resources. The model described in this report can be used as a tool by water-management agencies and other stakeholders to quantitatively evaluate the effects of potential increases in groundwater pumping on groundwater and surface-water resources in the basin. The Chamokane Creek model was constructed using the U.S. Geological Survey (USGS) integrated model, GSFLOW. GSFLOW was developed to simulate coupled groundwater and surface-water resources. The model uses 1,000-foot grid cells that subdivide the model domain by 102 rows and 106 columns. Six hydrogeologic units in the model are represented using eight model layers. Daily precipitation and temperature were spatially distributed and subsequent groundwater recharge was computed within GSFLOW. Streamflows in Chamokane Creek and its major tributaries are simulated in the model by routing streamflow within a stream network that is coupled to the groundwater-flow system. Groundwater pumpage and surface-water diversions and returns specified in the model were derived from monthly and annual pumpage values previously estimated from another component of this study and new data reported by study partners. The model simulation period is water years 1980-2010 (October 1, 1979, to September 30, 2010), but the model was calibrated to the transient conditions for water years 1999-2010 (October 1, 1998, to September 30, 2010). Calibration was completed by using traditional trial-and-error methods and automated parameter-estimation techniques. The model adequately reproduces the measured time-series groundwater levels and daily streamflows. At well observation points, the mean difference between simulated and measured hydraulic heads is 7 feet with a root-mean-square error divided by the total difference in water levels of 4.7 percent. Simulated streamflow was compared to measured streamflow at the USGS streamflow-gaging station-Chamokane Creek below Falls, near Long Lake (12433200). Annual differences between measured and simulated streamflow for the site ranged from -63 to 22 percent. Calibrated model output includes a 31-year estimate of monthly water budget components for the hydrologic system. Five model applications (scenarios) were completed to obtain a better understanding of the relation between groundwater pumping and surface-water resources. The calibrated transient model was used to evaluate: (1) the connection between the upper- and middle-basin groundwater systems, (2) the effect of surface-water and groundwater uses in the middle basin, (3) the cumulative impacts of claims registry use and permit-exempt wells on Chamokane Creek streamflow, (4) the frequency of regulation due to impacted streamflow, and (5) the levels of domestic and stockwater use that can be regulated. The simulation results indicated that streamflow is affected by existing groundwater pumping in the upper and middle basins. Simulated water-management scenarios show streamflow increased relative to historical conditions as groundwater and surface-water withdrawals decreased.

Washington↗

Hydrogeologic data for the southwestern coastal river basins, Connecticut

This report presents hydrologic and geologic data collected by the U.S. Geological Survey during an investigation of water resources in the southwestern coastal river basins of Connecticut in cooperation with the Connecticut Water Resources Commission. These basins occupy about 394 square miles in Connecticut and 46 square miles in New York, including the towns of Greenwich, Stamford, Darien, New Canaan, Norwalk, Wilton, Westport, Weston, Fairfield, Easton, and Bridgeport and parts of Danbury, Ridgefield, Redding, Bethel, Newtown, Trumbull, Monroe, Shelton, and Stratford. A companion interpretive report evaluating the water resources of the basins will be published as Connecticut Water Resources Bulletin No. 17. The data on the following pages serve to document and supplement that report and should be especially useful in planning the development of water resources at specific localities. Data were collected as part of this investigation during the period July 1963 through November 1966. Streamflow records from continuous-record gaging stations in the basins have been published annually along with data from other parts of the State in a series of U.S. Geological Survey reports entitled "Surface Water Records of Connecticut." Water-level measurements in wells throughout the State from 1960 through 1966, including most of those made as part of this investigation, are published in Connecticut Water Resources Bulletins No. 7 and No. 13. Most other data collected during this investigation are tabulated on the following pages. Included are some well records and chemical analyses of water samples collected prior to July 1963 and not previously published. The locations of sites at which data were collected are shown on plate A in the pocket at the back of the report. Data presented, unless otherwise noted, were collected by U.S. Geological Survey personnel.

Connecticut↗

Estimates of evapotranspiration in alkaline scrub and meadow communities of Owens Valley, California, using the Bowen-ratio, eddy-correlation, and penman-combination methods

In Owens Valley, evapotranspiration (ET) is one of the largest components of outflow in the hydrologic budget and the least understood. ET estimates for December 1983 through October 1985 were made for seven representative locations selected on the basis of geohydrology and the characteristics of phreatophytic alkaline scrub and meadow communities. The Bowen-ratio, eddy-correlation, and Penman-combination methods were used to estimate ET. The results of the analyses appear satisfactory when compared with other estimates of ET. Results by the eddy-correlation method are for a direct and a residual latent-heat flux that is based on sensible-heat flux and energy-budget measurements. Penman-combination potential-ET estimates were determined to be unusable because they overestimated actual ET. Modification of the psychrometer constant of this method to account for differences between heat-diffusion resistance and vapor-diffusion resistance permitted actual ET to be estimated. The methods described in this report may be used for studies in similar semiarid and arid rangeland areas in the Western United States. Meteorological data for three field sites are included in the appendix of this report. Simple linear regression analysis indicates that ET estimates are correlated to air temperature, vapor-density deficit, and net radiation. Estimates of annual ET range from 301 millimeters at a low-density scrub site to 1,137 millimeters at a high-density meadow site. The monthly percentage of annual ET was determined to be similar for all sites studied.

Water Supply Paper↗

Relationship of suspended sediment to streamflow in the Green River Basin, Wyoming

The relation of suspended-sediment concentration to water discharge was computed using regression analysis for 33 stations and 2 miscellaneous sites in the Green River basin, Wyoming. These relations show that suspended-sediment concentrations vary in direct proportion to streamflow. The number of coincident instantaneous suspended-sediment concentration and water-discharge values available for each regression analysis ranged from 6 to 98. Standard error of estimates for 35 relationships were usually large and correlation were relatively small. Large standard errors and small correlations are expected because of the complexity of the fluvial system. The effects of other factors, such as geology, topography, climate, soils, vegetation, and land use were not evaluated. Daily suspended-sediment discharges for four stations were computed by the ' sediment-transport-curve ' method described in this report , and compared with values computed by the traditional ' temporal-concentration-graph ' method. Annual sediment yields in tons per square mile drainage area, were compared in like manner. For those stations examined, values computed by the ' sediment-transport-curve ' method were within 58 percent of those computed by the temporal-concentration-graph ' method when only one year of record was used, but were within 12 to 21 percent when 2 to 4 years of record were averaged. (USGS)

Water-Resources Investigations Report↗

Municipal ground-water development and withdrawals in the central Lower Peninsula of Michigan, 1870-1987

Municipal water-supply systems in the central Lower Peninsula of Michigan were categorized into four regions on the basis of source of water for 1987. These categories included water systems that obtained water from aquifers in glacial drift, bedrock, or both, as well as those that obtained water from surface-water sources. Data on ground-water development were collected for 182 municipal water-supply systems for the period 1870-1987. Of the 182 systems, 135 used ground water for supply. Wells in glacial-drift aquifers supplied water for 60 municipalities; wells in bedrock aquifers supplied 58 municipalities. Combinations of wells in bedrock and glacial-drift aquifers supplied 17 municipalities. Surface-water sources supplied 45 municipalities; two municipalities used surface water and ground water. Of the 182 municipal systems, withdrawal data were available for only 145. Withdrawal data were collected for the period 1903-1985. Analysis of annual ground-water withdrawal data for the 145 municipal water-supply systems indicates that average annual per capita municipal ground-water withdrawal ranged from 60 gallons per day per person in 1915 to 166 gallons per day per person in 1973. The maximum reported groundwater withdrawal for the area was 103 million gallons per day in 1979. Records from most municipalities include long periods for which no ground-water withdrawal data are available. The average annual per capita data among the municipalities varies over the period of record because of incomplete reporting of pumping rates, unusually high pumping rates, short-term economic changes, and other changes not associated with local population changes.

Michigan↗

Waterfowl status report, 1976

This report contains information from the 1975-76 midwinter waterfowl survey, the 1976 waterfowl breeding population and production surveys, and the waterfowl harvest surveys for the 1975-76 hunting season. This information was provided by the U.S. Fish and Wildlife Service, the Canadian Wildlife Service, and various cooperating State wildlife conservation agencies. Winter surveys are composed of the midwinter survey reports submitted from each of the four flyways and the midwinter survey covering a portion of the west coast of Mexico. The breeding ground surveys section is composed of many individual reports that provide breeding population and production estimates for most waterfowl species within a major portion of their breeding range. The waterfowl harvest survey provides estimates of waterfowl hunting activity and success. Information from surveys of the wintering and breeding populations of waterfowl, coupled with data from the annual harvest survey, are instrumental in developing annual hunting regulations for waterfowl. Credit has been given to each individual or organization that submitted a report. Although some of the narrative statements have been condensed and a few tables deleted or condensed if they contain data presented elsewhere in this report, the essential information from each report has been retained. The breeding grounds survey strata (Fig. 1) for areas surveyed by Fish and Wildlife Service crews were renumbered in 1974.

Special Scientific Report - Wildlife↗

Floods in western Washington--Frequency and magnitude in relation to drainage basin characteristics

This report presents a method of determining the magnitude and frequency of expected floods applicable for any area in western Washington (fig. 1). A composite frequency curve was developed that expresses the relation to mean annual floods of floods having recurrence intervals from 1.03 to 50 yr. This composite frequency curve was based on the combined frequency curves for all gaging stations in the region with 5 or more years of record. Records for 131 stations, with drainage areas ranging from l to 2,700 sq mL, and recorded flood peaks ranging from 30 to 210,000 cfs were combined to obtain the composite curve. An equation was derived expressing the relationship between mean annual floods and basin characteristics. Those basin characteristics that may easily be determined from topographic maps and that significantly affect the peak discharge were compiled for all streams in the region on which 5 or more years of stream-flow records are available. These basin characteristics were correlated with mean annual flood of the streams, and as a result of this correlation a formula for the computation of the mean annual flood for any basin was derived. The limitations of the formula and its probable accuracy are discussed in the report. Included in the report are curves of magnitude and frequency of floods at all gaging stations in the region with 15 or more years of record. Also included is an enveloping curve of the maximum recorded discharges in the region.

Washington↗

Summary of annual records of chemical quality of water of the Arkansas River in Oklahoma and Arkansas, 1945-1952

This report summarizes information collected to date in the Arkansas River Basin in Oklahoma and Arkansas, and shows, within the limitations of present information, the chemical quality of water in the Arkansas River downstream from the Oklahoma-Kansas State line to its junction with the Mississippi River, and the influence of tributary in-flows. Additional data are being collected and further studies are planned. Hence, conclusions reached herein may be modified by more complete information at a later date. The Arkansas River is subject to many types of pollution downstream from the Oklahoma-Kansas State line, and its inferior quality along with an erratic flow pattern has caused it to be largely abandoned as a source of municipal and industrial water supply. Currently, the Arkansas River is not directly used as a source of public supply in any part of the basin in either Oklahoma or Arkansas. In general, the river water increases in chemical concentration downstream from the Oklahoma-Kansas State line to Tulsa due mainly to tributary inflow from the Salt Fork Arkansas River and the Cimarron River, both streams being sources of large amounts of both natural salts and industrial wastes. A decrease in chemical concentration is noted downstream from Tulsa due to tributary inflow from the Verdigris, Neosho, and Illinois rivers, with an increase in chemical concentration then noted due to tributary inflow from the Canadian River which is largely oil field wastes. A steady decrease in concentrations is then noted as the river progresses through Arkansas to the Mississippi River, as all major tributaries below the Canadian River have a dilution effect upon the chemical concentration of the Arkansas River water. Proposals for storage and regulating reservoirs on the Arkansas River in both Oklahoma and Arkansas have been made by the Corps of Engineers and others. Additional proposals are bing considered in the present Arkansas-White-Red River Basin Inter-Agency Sub-Committee studies. If constructed, these reservoirs will provide an opportunity for control of flow and beneficial use of Arkansas River water both at and downstream from these sites. Impoundment alone will greatly reduce the extremes in water-quality, and by reasonable control of municipal and industrial wastes, the water at some points on the river would be comparable in quality to many existing municipal and industrial supplies in the basin. (available as photostat copy only)

Open-File Report↗

Runoff characteristics of California streams

California streams exhibit a wide range of runoff characteristics that are related to the climatologic, topographic, and geologic characteristics of the basins they drain. The annual volume of runoff of a stream, expressed in inches, may be large or small, and daily discharge rates may be highly variable or relatively steady. The bulk of the annual runoff may be storm runoff, or snowmelt runoff, or a combination of both. The streamflow may be ephemeral, intermittent, or perennial; if perennial, base flow may be well sustained or poorly sustained. In this report the various runoff characteristics are identified by numerical index values. They are shown to be related generally to mean annual precipitation, altitude, latitude, and location with respect to the 11 geomorphic provinces in the California Region. With respect to mean annual precipitation on the watershed, streamflow is generally (1) ephemeral if the mean annual precipitation is less than 10 inches, (2) intermittent if the mean annual precipitation is between 10 and 40 inches, and (3) perennial if the mean annual precipitation is more than 40 inches. Departures from those generalizations are associated with (a) the areal variation of such geologic factors as the infiltration and storage capacities of the rocks underlying the watersheds, and (b) the areal variation of evapotranspiration loss as influenced by varying conditions of climate, soil, vegetal cover, and geologic structure. Latitude and altitude determine the proportion of the winter precipitation that will be stored for subsequent runoff in the late spring and summer. In general, if a watershed has at least 30 percent of its area above the normal altitude of the snowline on April 1, it will have significant snowmelt runoff. Snowmelt runoff in California is said to be significant if at least 30 percent of the annual runoff occurs during the 4 months, April through July. Storm runoff is said to be predominant if at least 65 percent of the annual runoff occurs during the 6 months, October through March. Base flow (ground-water outflow), as a factor in the regimen of streamflow, is qualified on the basis of the percentage of the mean annual runoff that occurs during the fair-weather months of August and September. If the sum of the August and September runoff exceeds 3.0 percent of the annual runoff, base flow is considered to be well sustained; if the percentage is between 1.5 and 3.0, base flow is considered to be fairly well sustained; if the percentage is less than 1.5, baseflow is considered to be poorly sustained. The characteristics of duration curves of daily streamflow are influenced by the regimen of runoff. The distribution of daily flow is skewed for all streams, but it is more skewed for streams whose flow is predominantly storm runoff than for streams that carry significantly large quantities of snowmelt. Least skewed is the distribution for streams that carry large quantities of base flow. Either of two characteristics of the duration curve may be used as an index of skew--the percentage of time that the mean discharge is equaled or exceeded or the ratio of the median discharge to the mean discharge. As for variability of daily discharge, the variability of storm-runoff streams is greater than that of snowmelt streams, and the lowest values of variability are associated with streams that carry large quantities of base flow. The index of variability used in this study was the ratio of the discharge equaled or exceeded 10 percent of the time to the discharge equaled or exceeded 90 percent of the time. The identification of streamflow characteristics by numerical index figures greatly facilitates comparison of the diverse runoff regimens of streams in the California Region.

Water Supply Paper↗

Hydrogeologic data for the Shetucket River basin, Connecticut

This report presents hydrologic and geologic data collected by the U.S. Geological Survey during an investigation of water resources in the Shetucket River basin of Connecticut in cooperation with the Connecticut Water Resources Commission. The Shetucket River basin occupies about 507 square miles in the eastern part of the State, including the towns of Andover, Ashford, Chaplin, Coventry, Mansfield, Scotland, Sprague, Windham, and Willington, and parts of Bolton, Canterbury, Columbia, Eastford, Ellington, Franklin, Lebanon, Lisbon, Hampton, Hebron, Norwich, Pomfret, Stafford, Tolland, Union, Vernon, and Woodstock. A companion interpretive report, Connecticut Water Resources Bulletin ll, (Thomas, and others, 1967), evaluates the water resources of the basin. The data on the following pages serve to document and supplement that report and should be especially useful in planning the development of water resources at specific localities. Data were collected as part of this investigation during the period July 1962 through December 1964. Streamflow records from continuous-record gaging stations in the basin for this period have been published annually along with data from other parts of the State in a series of U.S. Geological Survey reports entitled "Surface Water Records of Connecticut." Water-level measurements in wells throughout the State from 1960 through 1964, including those made as part of this investigation, are published in Connecticut Water Resources Bulletin 7 (Meikle and Baker, 1965). Most other data collected during this investigation are tabulated on the following pages. Included are some well records and chemical analyses of water samples collected prior to July 1962 and not previously published. The locations of sites at which data were collected are shown on plate A in the pocket at the back of the report. Plate A includes the locations of 98 sites where 2 to 6 miscellaneous measurements of streamflow were made during 1963 and 13 other sites where continuous records are maintained. Data for these sites have already been published in "Surface Water Records of Connecticut" and are not repeated here. Data presented~ unless otherwise noted, were collected by U.S. Geological Survey personnel.

Connecticut↗

Low-flow characteristics of streams in South Carolina

An ongoing understanding of streamflow characteristics of the rivers and streams in South Carolina is important for the protection and preservation of the State’s water resources. Information concerning the low-flow characteristics of streams is especially important during critical flow periods, such as during the historic droughts that South Carolina has experienced in the past few decades. Between 2008 and 2016, the U.S. Geological Survey, in cooperation with the South Carolina Department of Health and Environmental Control, updated low-flow statistics at 106 continuous-record streamgages operated by the U.S. Geological Survey for the eight major river basins in South Carolina. The low-flow frequency statistics included the annual minimum 1-, 3-, 7-, 14-, 30-, 60-, and 90-day mean flows with recurrence intervals of 2, 5, 10, 20, 30, and 50 years, depending on the length of record available at the streamflow-gaging station. Computations of daily mean flow durations for the 5-, 10-, 25-, 50-, 75-, 90-, and 95-percent probability of exceedance also were included. This report summarizes the findings from publications generated during the 2008 to 2016 investigations. Trend analyses for the annual minimum 7-day average flows are provided as well as trend assessments of long-term annual precipitation data. Statewide variability in the annual minimum 7-day average flow is assessed at eight long-term (record lengths from 55 to 78 years) streamgages. If previous low-flow statistics were available, comparisons with the updated annual minimum 7-day average flow, having a 10-year recurrence interval, were made. In addition, methods for estimating low-flow statistics at ungaged locations near a gaged location are described.

South Carolina↗

Water quality and aquatic toxicity data of 2002 spring thaw conditions in the upper Animas River watershed, Silverton, Colorado

This report presents hydrologic, water-quality, and biologic toxicity data collected during the annual spring thaw of 2002 in the upper Animas River watershed near Silverton, Colorado. The spring-thaw runoff is a concern because elevated concentrations of iron oxyhydroxides can contain sorbed trace metals that are potentially toxic to aquatic life. Water chemistry of streams draining the San Juan Mountains is affected by natural acid drainage and weathering of hydrothermal altered volcanic rocks and by more than a century of mining activities. The timing of the spring-thaw sampling effort was determined by reviewing historical climate and stream-flow hydrographs and current weather conditions. Twenty-one water-quality samples were collected between 11:00 AM March 27, 2002 and 6:00 PM March 30, 2002 to characterize water chemistry at the A-72 gage on the upper Animas River below Silverton. Analyses of unfiltered water at the A-72 gage showed a relation between turbidity and total-recoverable iron concentrations, and showed diurnal patterns. Copper and lead concentrations were related to iron concentrations, indicating that these elements are probably sorbed to colloidal iron material. Calcium, strontium, and sulfate concentrations showed overall decreasing trends due to dilution, but the loads of those constituents increased over the sampling period. Nine water-quality samples were collected near the confluence of Mineral Creek with the Animas River, the confluence of Cement Creek with the Animas River, and on the upper Animas River above the confluence with Cement Creek (three samples at each site). A total of six bulk water-toxicity samples were collected before, during, and after the spring thaw from the Animas River at the A-72 gage site. Toxicity tests conducted with the bulk water samples on amphipods did not show strong differences in toxicity among the three sampling periods; however, toxicity of river water to fathead minnows showed a decreasing trend during the course of the study.

Colorado↗

Hydrologic and climatologic data, 1967, Salt Lake County, Utah

An investigation of the water resources of Salt Lake County, Utah, was undertaken by the Water Resources Division of the U.S. Geological Survey in July 1963. This investigation is a cooperative project financed chiefly by equal contributions of the State of Utah and the Federal Government in accordance with an agreement between the Division of Water Rights, Utah Department of Natural Resources, and the Geological Survey. The investigation was financed during the period covered by this report by the following organizations: Utah Division of Water Rights (formerly State Engineer), Utah Division of Water Resources (formerly Water and Power Board), Salt Lake County, Salt Lake County Water Conservancy District, Central Utah Water Conservancy District, Metropolitan Water District of Salt Lake City, City of Murray, Granger-Hunter Improvement District, Taylorsville-Bennion Improvement District, Holladay Water Company, Magna Water and Sewer District, U.S. Bureau of Reclamation, U.S. Geological Survey. The investigation encompasses the collection and interpretation of a large variety of climatologic, hydrologic, and geologic data in and near Salt Lake County. Utah Basic-Data Releases 11-13 contain data collected through 1966. This release contains climatologic and surfacewater data for the 1967 water year (October 1966 to September 1967) and ground-water data collected during the 1967 calendar year. A similar annual release will contain data collected during the remainder of the investigation, and interpretive reports will be prepared as the investigation proceeds. Organizations that furnished data are acknowledged in station descriptions and footnotes to tables.

Utah↗