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At least 1,009 records · Page 56Linked to original sources
USGS2025

Effects of beaver dams and ponds on the transport and deposition of suspended sediment in urban streams of the Tualatin River Basin, northwestern Oregon

Significant Findings This study investigated the effects of natural beaver dams and ponds on sediment transport and deposition in two urban beaver-affected reaches in the Tualatin River Basin, northwestern Oregon. Data were collected during 2016–17 from Fanno Creek at Greenway Park (between SW Hall Boulevard and SW Pearson Court) and Bronson Creek (between NW Laidlaw Road and NW Kaiser Road); each study reach contained multiple beaver dams. Continuous turbidity, discrete suspended-sediment samples, and streamflow measurements were collected during storms and baseflow periods to calculate suspended-sediment loads (SSLs) and to compare differences in SSLs upstream and downstream from the two beaver-affected reaches. Turbidity was measured continuously upstream, within, and downstream from these reaches to evaluate seasonal and longitudinal turbidity patterns and fluctuations. The volume and mass of sediment deposited in a large pond along the Fanno Creek study reach were also estimated. Study results include: Instantaneous SSLs at the upstream reach boundaries often were greater at Bronson Creek compared to Fanno Creek during storm events. These differences were likely caused by the greater mean basin slope upstream from the Bronson Creek reach and its proximity to the headwaters in the Tualatin Mountains. In contrast, the frequency of sediment transport events was greater at the upstream boundary of the Fanno Creek study reach than at the upstream boundary of the Bronson Creek study reach, likely because Fanno Creek has a larger upstream contributing area and more frequent streamflow runoff events typical of urban streams. During water year 2017, approximately 140 metric tons (t) of sediment (11 percent of the total incoming load) were deposited in the Fanno Creek study reach, and 1,420 t of sediment (89 percent of the total incoming load) were deposited in the Bronson Creek study reach. Longitudinal reductions in turbidity were observed in both study reaches but varied among the two reaches. Turbidity reductions along the Fanno Creek study reach were associated with sediment deposition and storage in the south pond, a large floodplain pond formed by a beaver dam. Turbidity decreased gradually along the Bronson Creek study reach, indicating that sediment was deposited between the upstream and downstream boundaries. Differences in decreases in SSLs and turbidity among the two study reaches were attributed to reach characteristics, such as beaver dam characteristics, stream-floodplain hydraulic connections, and the type and density of the vegetation. The eastern part of the south pond in the Fanno Creek study reach trapped approximately 1,100 cubic meters of sediment (estimated 250 t) from 2012 to 2016 (the period between when beaver dams were first built in the reach and when topographic surveys were collected for this study). This amount is equivalent to about one seventh of the mean annual SSL moving through Fanno Creek as estimated by a previous study at the downstream U.S. Geological Survey streamgage at Fanno Creek at Durham Road (14206950). Beaver dams and ponds in urban streams can reduce SSLs and trap sediment. Consideration of reach-specific factors influencing the effects of beaver dams on sediment transport could help create realistic expectations for restoration programs about this potential benefit associated with beaver activity.

Oregon↗
USGS2003

Sedimentation survey of Lago de Matrullas, Puerto Rico, December 2001

Lago de Matrullas reservoir, constructed in 1934, is located at an altitude of approximately 730 meters above mean sea level in the municipality of Orocovis in central Puerto Rico, and has a drainage area of 11.45 square kilometers. The reservoir is part of the Puerto Rico Electric Power Authority Toro Negro Hydroelectric Project, which also includes the Lago El Guineo reservoir and a hydroelectric plant to the south of the insular hydrographic divide. Historically, the drainage area had been protected from soil erosion by dense vegetation and the lack of basin development. However, transportation, potable water, and electric power infrastructure construction has facilitated development in rural areas resulting in the clearing of land. This trend in land-use changes is impacting the useful life of Lago de Matrullas. The reservoir storage capacity has been reduced from 3.71 million cubic meters in 1934 to 3.08 million cubic meters in 2001. This represents a total storage-capacity loss of 0.63 million cubic meters by 2001 (17 percent), or a long-term annual storage loss of 0.25 percent per year. The sediment trapping efficiency of Lago de Matrullas has been estimated at approximately 90 percent. If the current long-term sedimentation rate continues, Lago de Matrullas would fill by the year 2328. However, this life expectancy could be reduced at a faster than predicted rate as a result of rural development in the Lago de Matrullas basin and the high sediment trapping efficiency of the reservoir.

Water-Resources Investigations Report↗
USGS1978

Low-flow characteristics of streams in the lower Wisconsin River basin

Low-flow characteristics of streams in the lower Wisconsin River basin are presented. Included are estimates of low-flow frequency and flow duration at 11 gaging stations; low-flow frequency characteristics at 26 low-flow partial-record stations and 70 miscellaneous sites; and a list of low-flow discharge measurements at 155 miscellaneous sites where insufficient data were available to estimate low-flow characteristics. Relations are provided to estimate low-flow characteristics at ungaged sites and at sites where one base-flow discharge measurement is available. The relationships were determined from multiple regression analyses that related the low-flow characteristics at gaging stations and low-flow partial-record stations to basin characteristics. The standard error of estimate is provided for each method of estimating the annual minimum 7-day mean flow below which the flow will fall on the average of once in 2 years and once in 10 years. Standard error provides the user with the expected degree of accuracy for each method. Low-flow characteristics estimated for the lower Wisconsin River basin have a high degree of reliability when compared with other basins in Wisconsin, Reliable estimates appear to be related to the relatively uniform geologic features in the basin.

Wisconsin↗
USGS2021

Sediment concentrations and loads upstream from and through John Redmond Reservoir, east-central Kansas, 2010–19

Streambank erosion and reservoir sedimentation are primary concerns of resource managers in Kansas and throughout many regions of the United States and negatively affect flood control, water supply, and recreation. The Cottonwood and upper Neosho Rivers drain into John Redmond Reservoir, and since reservoir completion in 1964, there has been substantial conservation-pool sedimentation and storage loss in John Redmond Reservoir, causing storage capacity losses more rapidly than most other Federal reservoirs in Kansas. The U.S. Geological Survey (USGS), in cooperation with the Kansas Water Office, has monitored water quality (temperature, specific conductance, and turbidity) on the Cottonwood River (upstream from the reservoir) and Neosho River (upstream and downstream from the reservoir) since 2007 with additional sites added in 2009. The purpose of this report is to quantify suspended-sediment concentrations, loads, and yields entering and exiting John Redmond Reservoir during January 1, 2010, through December 31, 2019. Three water-quality monitoring sites were upstream from the reservoir (Cottonwood River near Plymouth, Kansas [USGS site 07182250; hereinafter referred to as “Cottonwood”]; Neosho River at Burlingame Road near Emporia, Kans. [USGS site 07179750; hereinafter referred to as “Burlingame”]; and Neosho River at Neosho Rapids, Kans. [USGS site 07182390; hereinafter referred to as “Neosho Rapids”]), and one water-quality monitoring site was downstream from the reservoir (Neosho River at Burlington, Kans. [USGS site 07182510; hereinafter referred to as “Burlington”]). The Neosho Rapids streamgage is downstream from the confluence of the Cottonwood and upper Neosho Rivers and has a contributing drainage area accounting for 91 percent of the total contributing drainage area to John Redmond Reservoir. Continuously measured streamflow, water quality, and discrete water-quality data were used to develop updated regression models to compute suspended-sediment concentrations, loads, and yields upstream and downstream from John Redmond Reservoir in east-central Kansas. Several turbidity sensors were deployed during the analysis period, and there are no established relations between the sensors; therefore, individual models for each sensor were developed. Model statistics for the turbidity and suspended-sediment concentration linear regression models were better (based on the coefficient of determination, root mean square error, and model standard percentage error) than the streamflow and suspended-sediment concentration linear regression models, indicating better model performance. Computed concentrations, loads, and yields do not account for the ungaged 9 percent of the drainage basin downstream from the Neosho Rapids streamgage. Mean daily suspended-sediment loads upstream from the reservoir were largest at Neosho Rapids (2,250 tons), second largest at Cottonwood (2,180 tons), and smallest at Burlingame (624 tons). Streamflow at Burlington was predominately regulated by reservoir releases, and mean daily suspended-sediment loads were smaller (286 tons) than at upstream sites. Among the upstream sites, Cottonwood had the largest mean daily suspended-sediment concentration (179 milligrams per liter [mg/L]), followed by Neosho Rapids (162 mg/L), and Burlingame (108 mg/L). Burlington had the smallest mean daily suspended-sediment concentration of all sites (46 mg/L). Annual reservoir trapping efficiency ranged from 82 to 94 percent, and the largest sediment mass trapped was during 2019 (2,230,000 tons). Reservoir storage decreased an estimated 7,750 acre-feet during 2010 and 2014–19. Using the mean trapping efficiency to estimate suspended-sediment loads during years with missing data (2011–13), the total estimated reservoir storage lost to sedimentation for the analysis period (2010–19) was 8,690 acre-feet, about 17 percent of the remaining storage space reported in 2007. The mean annual sedimentation rate during the analysis period (747 acre-feet per year) was about 85 percent larger than the design sedimentation rate (404 acre-feet per year) originally projected during construction. Different reservoir outflow management strategies, including operating near normal capacity as opposed to higher flood pool levels, could reduce the total reservoir storage lost by 3 percent (about 261 acre-feet), which is equal to 14 percent of the total sediment removed during the dredging operation in 2016. During the study period, about 56 percent of the total suspended-sediment load was transported during streamflows greater than the National Weather Service flood action stage at the upstream sites (0.1–5 percent of the record; Cottonwood mean: 48 percent; Burlingame mean: 40 percent; Neosho Rapids mean: 78 percent). Disproportionately large sediment loads were delivered during short periods of time, and localized efforts of stream erosion protection (streambank stabilization, riparian buffers) were likely to be overwhelmed. Precipitation frequency and intensity are projected to continue to increase in this region; therefore, future sediment reduction strategies that account for extreme episodic events may be beneficial. Changes to reservoir outflow management could also minimize sediment accumulation while still preserving flood control. Continued investigation of sediment reduction measures is necessary for future mitigation with the understanding that sedimentation rate is largely driven by high flows. Results from this study can be used to calibrate sediment models, explore sediment reduction strategies, highlight the importance of continued water-quality monitoring to determine effectiveness and changes in sediment transport, and assess the ability of John Redmond Reservoir to support designated uses into the future.

Kansas↗
USGS2026

Understanding the occurrence and distribution of per- and polyfluoroalkyl substances (PFAS) in surface waters of the nontidal Passaic River Basin

This study, completed by the U.S. Geological Survey in cooperation with the North Jersey District Water Supply Commission (NJDWSC), was designed to characterize the occurrence and distribution of per- and polyfluoroalkyl substances (PFAS) in surface waters of the nontidal Passaic River Basin in New Jersey that have the potential to affect public-drinking-water quality. In 2025, 37 sites in the Wanaque, Ramapo, Pompton, and Passaic River watersheds were sampled in January, March, July, and September under base-flow conditions and a subset of sites was sampled during two rain events. Samples were analyzed for 40 individual PFAS and total organic carbon and a subset of samples was analyzed for 1,4-dioxane and trace elements. Fifteen PFAS were detected at least once, with individual concentrations ranging from 0.42 to 28 nanograms per liter (ng/L; median, 2.8 ng/L). Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) were widespread and detected in 100 and 97 percent of the samples, respectively. Concentrations of PFOA and PFOS ranged from 1.2 to 28 ng/L (median, 7.7 ng/L) and from 0.52 to 12 ng/L (median, 3.8 ng/L), respectively. Generally, concentrations were lower in the Wanaque and Ramapo River watersheds compared to the Pompton and Passaic River watersheds. Concentrations of PFOA and PFOS were highest in July and September when flows were low. During rain events, median concentrations of PFOS were elevated compared to those observed under base-flow conditions, indicating potential inputs from non-point sources. To understand potential drivers of PFAS concentrations, land cover and potential PFAS sources were summarized for each sampling site, and an accumulated wastewater model was used to estimate the percentage of wastewater from upstream municipal and industrial sources in all flowlines of the Passaic River Basin. Developed land, the number of potential sources, and the mean-annual accumulated wastewater percentage were highly correlated with PFAS concentrations and Deciduous Forests were negatively related to concentrations. Data provided by this study can be used by water purveyors and resource managers to make treatment and mitigation decisions to minimize PFAS in local surface waters used as drinking-water resources.

New Jersey, New York↗
USGS2002

Hydrologic characteristics of Bear Creek near Silver Hill and Buffalo River near St. Joe, Arkansas, 1999-2000

The Buffalo River and its tributary Bear Creek are in the White River Basin in the Ozark Plateaus in north-central Arkansas. Analysis of streamflow measurements and water-quality samples at a site on Bear Creek and a site on the Buffalo River in Searcy County, Arkansas, quantify differences between the two sites during calendar years 1999 and 2000. Streamflow and water quality also vary seasonally at each site. Mean annual streamflow was substantially larger at the Buffalo River site (836 and 719 cubic feet per second in 1999 and 2000) than at the Bear Creek site (56 and 63 cubic feet per second). However, during times of low flow, discharge of Bear Creek comprises a larger proportion of the flow of the Buffalo River. Concentrations of nutrients, fecal-indicator bacteria, dissolved organic carbon, and suspended sediment generally were greater in samples from Bear Creek than in samples from the Buffalo River. Statistically significant differences were detected in concentrations of nitrite plus nitrate, total nitrogen, dissolved phosphorus, orthophosphorus, total phosphorus, fecal coliform bacteria, and suspended sediment. Loads varied between sites, hydrologic conditions, seasons, and years. Loads were substantially higher for the Buffalo River than for Bear Creek (as would be expected because of the Buffalo?s higher streamflow). Loads contributed by surface runoff usually comprised more than 85 percent of the annual load. Constituent yields (loads divided by drainage area) were much more similar between sites than were loads. Flow-weighted concentrations and dissolved constituent yields generally were greater for Bear Creek than yields for the Buffalo River and flowweighted concentrations yields were higher than typical flow-weighted concentrations and yields in undeveloped basins, but lower than flow-weighted concentrations and yields at a site in a more developed basin.

Water-Resources Investigations Report↗
USGS2002

Streamflow and nutrient data for the Yazoo River below Steele Bayou near Long Lake, Mississippi, 1996-2000

Increased nutrient loading to the Gulf of Mexico from off-continent flux has been identified as contributing to the increase in the areal extent of the low dissolved-oxygen zone that develops annually off the Louisiana and Texas coast. The proximity of the Yazoo River Basin in northwestern Mississippi to the Gulf of Mexico, and the intensive agricultural activities in the basin have led to speculation that the Yazoo River Basin contributes a disproportionate amount of nitrogen and phosphorus to the Mississippi River and ultimately to the Gulf of Mexico. An empirical measurement of the flux of nitrogen and phosphorus from the Yazoo Basin has not been possible due to the hydrology of the lower Yazoo River Basin. Streamflow for the Yazoo River below Steele Bayou is affected by backwater from the Mississippi River. Flow at the gage is non-uniform and varying, with bi-directional and reverse flows possible. Streamflow was computed by using remote sensing and acoustic and conventional discharge and velocity measurement techniques. Streamflow from the Yazoo River for the 1996-2000 period accounted for 2.8 percent of the flow of the Mississippi River for the same period. Water samples from the Yazoo River were collected from February 1996 through December 2000 and were analyzed for total nitrogen, nitrate, total phosphorus, and orthophosphorus as part of the U.S. Geological Survey National Water-Quality Assessment Program. These data were used to compute annual loads of nitrogen and phosphorus discharged from the Yazoo River for the period 1996-2000. Annual loads of nitrogen and phosphorus were calculated by two methods. The first method used multivariate regression and the second method multiplied the mean annual concentration by the total annual flow. Load estimates based on the product of the mean annual concentration and the total annual flow were within the 95 percent confidence interval for the load calculated by multivariate regression in 10 of 20 cases. The Yazoo River loads, compared to average annual loads in the Mississippi River, indicated that the Yazoo River was contributing 1.4 percent of the total nitrogen load, 0.7 percent of the nitrate load, 3.4 percent of the total phosphorus load, and 1.6 percent of the orthophosphorus load during 1996 - 2000. The total nitrogen, nitrate, and orthophosphorus loads in the Yazoo River Basin were less than expected, whereas the total phosphorus load was slightly higher than expected based on discharge.

Water-Resources Investigations Report↗
USGS2026

Magnitude and frequency of peak and low flows in the Elkhorn River Basin, Nebraska, 1881–2022

Flood-frequency analysis is based on records of annual maximum instantaneous flows observed at long-term streamgages with 10 years or more of operation. Since the last flood-frequency analysis in Nebraska, an additional 30 years of annual peak-flow data have become available, and new flood-frequency analysis techniques have been developed. Moreover, the Elkhorn River Basin in north-central and eastern Nebraska has experienced two of the three highest magnitude floods on record in 2010 and 2019. The U.S. Geological Survey, in cooperation with the Nebraska Department of Transportation, analyzed flow frequency at streamgages in the Elkhorn River Basin in Nebraska. Flow data from the U.S. Geological Survey and the Nebraska Department of Water, Energy, and Environment annual hydrographic reports were utilized to analyze peak flows. The Peak flow FreQuency (PeakFQ) software was used to perform a flood-frequency and nonstationarity analysis on the selected streamgages in the Elkhorn River Basin in Nebraska. Results of the peak-flow nonstationarity analysis indicate that, of the 23 streamgages analyzed for peak-flow frequency, 4 showed trends that were likely increasing for annual peak flows, whereas 3 indicated trends that were somewhat likely to be increasing. For 11 streamgages, the trend was categorized as about as likely as not, meaning there is less than a 70-percent chance of the trend being either upward or downward. Additionally, 2 streamgages exhibited trends that were somewhat likely to be decreasing, and 3 streamgages showed trends that were likely decreasing. Low-flow streamflows and nonstationarity in the Elkhorn River Basin were analyzed for low flow periods representing the 1-day, 7-day, and 30-day flows at 21 streamgages using the Hydrologic Toolbox software. Spatially, the nonstationarity analysis results indicated likely increasing or somewhat increasing trend likelihoods for the 1-day, 7-day, and 30-day low flows for many of the Elkhorn streamgages downstream from the Elkhorn River at Ewing, Nebr., streamgage (U.S. Geological Survey station 06797500) and on eastern tributaries during the period of record.

Nebraska↗
USGS1996

Estimation of flood-frequency characteristics of small urban streams in North Carolina

A statewide study was conducted to develop methods for estimating the magnitude and frequency of floods of small urban streams in North Carolina. This type of information is critical in the design of bridges, culverts and water-control structures, establishment of flood-insurance rates and flood-plain regulation, and for other uses by urban planners and engineers. Concurrent records of rainfall and runoff data collected in small urban basins were used to calibrate rainfall-runoff models. Historic rain- fall records were used with the calibrated models to synthesize a long- term record of annual peak discharges. The synthesized record of annual peak discharges were used in a statistical analysis to determine flood- frequency distributions. These frequency distributions were used with distributions from previous investigations to develop a database for 32 small urban basins in the Blue Ridge-Piedmont, Sand Hills, and Coastal Plain hydrologic areas. The study basins ranged in size from 0.04 to 41.0 square miles. Data describing the size and shape of the basin, level of urban development, and climate and rural flood charac- teristics also were included in the database. Estimation equations were developed by relating flood-frequency char- acteristics to basin characteristics in a generalized least-squares regression analysis. The most significant basin characteristics are drainage area, impervious area, and rural flood discharge. The model error and prediction errors for the estimating equations were less than those for the national flood-frequency equations previously reported. Resulting equations, which have prediction errors generally less than 40 percent, can be used to estimate flood-peak discharges for 2-, 5-, 10-, 25-, 50-, and 100-year recurrence intervals for small urban basins across the State assuming negligible, sustainable, in- channel detention or basin storage.

North Carolina↗
USGS2004

Status assessment and conservation plan for the yellow-billed loon (Gavia adamsii)

Because of its restricted range, small population size, specific habitat requirements, and perceived threats to its breeding habitat, the Yellow-billed Loon (Gavia adamsii) is a species of conservation concern to the U.S. Fish and Wildlife Service and the subject of a petition for listing under the Endangered Species Act. This Status Assessment synthesizes current information on population size, trends, and potential threats to Yellow-billed Loons, and the Conservation Plan identifies research and monitoring activities that would contribute to the conservation of this species. The preparation of this report was requested and funded by the U.S. Fish and Wildlife Service, Nongame Bird Office, Region 7.The Status Assessment and Conservation Plan for the Yellow-billed Loon can be summarized as follows:? Northern Alaska breeding grounds support an average of 3,369 individuals, including <1,000 nesting pairs in most years. The Yellow-billed Loon ranks as one of the 10 rarest birds that breeds regularly within the main land U.S. and one of only 20 with a North American population <16,000 individuals (Section 6-E).? There is no evidence of a long-term trend in the Yellow-billed Loon population index since 1986 (-0.9% annual change), but interpretation of surveys is complicated by changes in observers and high annual variation, and the 95% confidence interval is large (-3.6% to +1.8% annual change). The low reproductive potential of Yellow-billed Loons suggests that recovery from a substantial decline would not occur rapidly. There are no systematic surveys of Canadian and Russian breeding populations (Section 6-F).? The expansion of the oil industry into prime Yellow-billed Loon breeding habitat is a recent occurrence and we lack the necessary information to accurately predict its effect on the population. Most of northern Alaska?s Yellow-billed Loons (91%) occur on the National Petroleum Reserve?Alaska, virtually all of which is open or proposed to be opened to development and where there is no permanent or legal protection of Yellow-billed Loon habitat (Section 7-A).? Other potential factors affecting the population are also addressed, such as contaminants, subsistence hunting, by catch in subsistence and commercial fisheries on the breeding and wintering grounds, and health of the marine ecosystem off the coast of East Asia where Alaska?s Yellow-billed Loons winter, but data are lacking to reach strong conclusions on most issues.? The conservation goal adopted by the Alaska Loon and Grebe Working Group for the Yellow-billed Loon is to maintain a stable breeding population, of current size and distribution, across the extent of the loon?s breeding range in Alaska. The Conservation Plan, designed to provide information necessary to meet this goal, puts forth seven objectives: 1) Conduct annual population surveys having negligible bias and 80% statistical power to detect a 3.4% annual decline, a decline that would result in a 50% loss of the population within 20 years; 2) Obtain an unbiased and reliable estimate of the size of Alaska?s breeding population; 3) Identify geographic regions and habitats of importance during breeding, staging, and wintering periods; 4) Use demographic models to evaluate risks to the population; 5) Identify potential effects of oil development on the breeding grounds and measures necessary to minimize the effects; 6) Evaluate the magnitude of subsistence harvest and by catch and their potential effects on the population; 7) Develop a continent-wide and range-wide context for Alaska?s population and habitat objectives.

Scientific Investigations Report↗
USGS2024

Estimated groundwater recharge for mid-century and end-of-century climate projections, Kaua‘i, O‘ahu, Moloka‘i, Lāna‘i, Maui, and the Island of Hawai‘i

Demand for freshwater in the State of Hawaiʻi is expected to increase by roughly 13 percent from 2020 to 2035. Groundwater availability in Hawaiʻi is affected by a number of factors, including land cover, rainfall, runoff, evapotranspiration, and climate change. To evaluate the availability of fresh groundwater under projected future-climate conditions, estimates of groundwater recharge are needed. A water-budget model with a daily computation interval was used to estimate the spatial distribution of groundwater recharge for Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and the Island of Hawaiʻi for recent climate conditions and three future-climate scenarios. Climate conditions from 1978 to 2007 were used as the reference period for recent climate conditions on each island. The three future-climate scenarios were developed using available high-resolution downscaled climate projections that include (1) a mid-century scenario using projected rainfall conditions for the Representative Concentration Pathway (RCP) scenario during 2041–71 with a total radiative forcing of 8.5 watts per square meter by the year 2100 (RCP8.5 2041–71 scenario), (2) a dry-climate scenario using projected rainfall conditions for the RCP8.5 scenario during 2071–99, and (3) a wet-climate scenario using projected rainfall conditions for the “Special Report on Emissions Scenarios” A1B scenario during 2080–99 for Maui, the RCP4.5 scenario during 2080–99 for Kauaʻi, Lānaʻi, and the Island of Hawaiʻi, and the RCP8.5 scenario during 2080–99 for Oʻahu and Molokaʻi. An additional drought scenario was added for Lānaʻi to assess the effect of extreme drought conditions during 2008–12 on groundwater recharge. All scenarios used 2020 land cover. Mean annual groundwater recharge is estimated to decrease between 5 and 55 percent on all six islands in this study for the mid-century and dry-climate scenarios relative to the reference-period recharge. Recharge is estimated to increase for Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, and Maui between 2 and 43 percent and decrease for the Island of Hawaiʻi by about 4 percent for the wet-climate scenario. Comparing the mid-century and dry-climate scenarios, all 110 aquifer systems (management areas defined by the State of Hawaiʻi Commission on Water Resource Management) from all six islands show similar direction in drying (104 aquifer systems) or wetting (6 aquifer systems) changes for recharge. However, among the three future scenarios, only 35 of 110 aquifer systems show similar direction in drying (30 aquifer systems) or wetting (5 aquifer systems) changes for recharge.

Hawaii↗
USGS2009

Hydrogeologic Framework and Occurrence and Movement of Ground Water in the Upper Humboldt River Basin, Northeastern Nevada

The upper Humboldt River basin encompasses 4,364 square miles in northeastern Nevada, and it comprises the headwaters area of the Humboldt River. Nearly all flow of the river originates in this area. The upper Humboldt River basin consists of several structural basins, in places greater than 5,000 feet deep, in which basin-fill deposits of Tertiary and Quaternary age and volcanic rocks of Tertiary age have accumulated. The bedrock of each structural basin and adjacent mountains is composed of carbonate and clastic sedimentary rocks of Paleozoic age and crystalline rocks of Paleozoic, Mesozoic and Cenozoic age. The permeability of bedrock generally is very low except for carbonate rocks, which can be very permeable where circulating ground water has widened fractures through geologic time. The principal aquifers in the upper Humboldt River basin occur within the water-bearing strata of the extensive older basin-fill deposits and the thinner, younger basin-fill deposits that underlie stream flood plains. Ground water in these aquifers moves from recharge areas along mountain fronts to discharge areas along stream flood plains, the largest of which is the Humboldt River flood plain. The river gains flow from ground-water seepage to its channel from a few miles west of Wells, Nevada, to the west boundary of the study area. Water levels in the upper Humboldt River basin fluctuate annually in response to the spring snowmelt and to the distribution of streamflow diverted for irrigation of crops and meadows. Water levels also have responded to extended periods (several years) of above or below average precipitation. As a result of infiltration from the South Fork Reservoir during the past 20 years, ground-water levels in basin-fill deposits have risen over an area as much as one mile beyond the reservoir and possibly even farther away in Paleozoic bedrock.

Scientific Investigations Report↗
USGS2016

Flood-inundation maps for a 9.1-mile reach of the Coast Fork Willamette River near Creswell and Goshen, Lane County, Oregon

Digital flood-inundation maps for a 9.1-mile reach of the Coast Fork Willamette River near Creswell and Goshen, Oregon, were developed by the U.S. Geological Survey (USGS) in cooperation with the U.S. Army Corps of Engineers (USACE). The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/ , depict estimates of the areal extent and depth of flooding corresponding to selected stages at the USGS streamgage at Coast Fork Willamette River near Goshen, Oregon (14157500), at State Highway 58. Current stage at the streamgage for estimating near-real-time areas of inundation may be obtained at http://waterdata.usgs.gov/or/nwis/uv/?site_no=14157500&PARAmeter_cd=00065,00060 . In addition, the National Weather Service (NWS) forecasted peak-stage information may be used in conjunction with the maps developed in this study to show predicted areas of flood inundation. In this study, areas of inundation were provided by USACE. The inundated areas were developed from flood profiles simulated by a one-dimensional unsteady step‑backwater hydraulic model. The profiles were checked by the USACE using documented high-water marks from a January 2006 flood. The model was compared and quality assured using several other methods. The hydraulic model was then used to determine eight water-surface profiles at various flood stages referenced to the streamgage datum and ranging from 11.8 to 19.8 ft, approximately 2.6 ft above the highest recorded stage at the streamgage (17.17 ft) since 1950. The intervals between stages are variable and based on annual exceedance probability discharges, some of which approximate NWS action stages. The areas of inundation and water depth grids provided to USGS by USACE were used to create interactive flood‑inundation maps. The availability of these maps with current stage from USGS streamgage and forecasted stream stages from the NWS provide emergency management personnel and residents with information that is critical for flood response activities, such as evacuations and road closures as well as for post flood recovery efforts.

Oregon↗
USGS1978

Appraisal of shallow ground-water resources and management alternatives in the Upper Peace and Eastern Alafia River Basins, Florida

In southwest Florida, the shallow aquifer system underlying the 1,250-square-mile upper Peace and eastern Alafia River basins is a relatively untapped source of supply. The aquifer system ranges between 50 and 300 feet thick and is composed of a surficial sand unit underlain by a limestone unit. Sand and clay confining beds separate the shallow aquifer system from the highly productive, extensively developed deep aquifer system. The hydrologic budget of the area indicates that annual leakage of water from the shallow to the deep aquifer system is 2.6 inches while annual pumpage from the deep aquifer system averages 5.5 inches. Management alternatives to be considered for efficient use of the shallow ground-water resources include development by withdrawal wells or connector wells for recharge. One solution for a gridded network of wells consists of 540 wells spaced 7,000 feet apart, each producing 453 gallons per minute. The network would derive water to meet demand by capturing water that would normally have run off evapotranspired. (Woodard-USGS)

Florida↗
USGS1979

Floods in Georgia, magnitude and frequency: Techniques for estimating the magnitude and frequency of floods in Georgia with compilation of flood data through 1974

Regional relations are defined for estimating the magnitude and frequency of floods having recurrence intervals of 2, 5, 10, 25, 50, and 100 years on streams with natural flow in Georgia. Multiple-regression analyses were used to define the relationship between the flood-discharge frequency of annual peak discharges for streams draining 0.1 to 1,000 square miles and 10 climatological and physical basin characteristics. The analyses indicate that the drainage area of the basin is the most significant characteristic. Five regions having distinct flood-discharge frequency characteristics are delineated. Individual relations of flood magnitude and frequency to drainage area are given for parts of the main stems of the major rivers without significant regulation draining more than 1,000 square miles. (Kosco-USGS)

Georgia↗
USGS1983

Magnitude and frequency of flooding on small urban watersheds in the Tampa Bay area, west-central Florida

Hydrologic data collected on nine small urban watersheds in the Tampa Bay area of west-central Florida and a method for estimating peak discharges in the study area are described. The watersheds have mixed land use and range in size from 0.34 to 3.45 square miles. Watershed soils, land use, and storm-drainage system data are described. Urban development ranged from a sparsely populated area with open-ditch storm sewers and 19% impervious area to a completely sewered watershed with 61% impervious cover. The U.S. Geological Survey natural-basin and urban-watershed models were calibrated for the nine watersheds using 5-minute interval rainfall data from the Tampa, Florida, National Weather Service rain gage to simulate annual peak discharge for the period 1906-52. A log-Pearson Type III frequency analysis of the simulated annual maximum discharge was used to determine the 2-, 5-, 10-, 25-, 50-, and 100-year flood discharges for each watershed. Flood discharges were related in a multiple-linear regression to drainage area, channel slope, detention storage area, and an urban-development factor determined by the extent of curb and gutter street drainage and storm-sewer system. The average standard error for the regional relations ranged from + or - 32 to + or - 42%. (USGS)

Florida↗
USGS1979

Water-level predictions for Indian Wells Valley ground-water basin, California, 1978

Ground-water pumpage in Indian Wells Valley, virtually a closed basin in the Mojave Desert of southern California, has increased gradually since 1945 and presently exceeds the long-term mean annual recharge (perennial supply). In order to aid in the understanding and management of the ground-water basin, a digital ground-water model was constructed by the U.S. Geological Survey. Since the original development of this model, conditions in the basin, including areal distribution and rates of ground-water pumpage, have changed. The results of the present simulation for the period 1969-76 constitute a second verification of the original model. Calculated heads for 1976 agree well with the observed heads, indicating a good calibration of the original model. A predictive simulation for the period 1977-2020 used pumpage values increasing from about 15,500 acre-feet per year to about 26,000 acre-feet per year. The pumpage used in this report reflects a slightly slower growth rate and a more concentrated pattern of development than that investigated when the model was originally developed. The effects of this pattern of pumpage are reflected in the water levels simulated by the model. Predicted drawdowns for 1983 are less extensive but locally more severe than those predicted earlier. The reversal of the hydraulic gradient between China Lake playa and the city of Ridgecrest, as produced by these drawdowns by the year 2020, suggests that the water-quality effects of such drawdowns should be investigated, as this could result in inferior water from the China Lake playa area flowing southward into areas of withdrawal.

California↗
USGS2025

Estimation of baseflow and flooding characteristics for East Canyon Creek, Summit and Morgan Counties, Utah

An improved understanding of hydrologic responses to changing climatic conditions is needed to better inform water management practices. East Canyon Creek, a perennial, snowmelt-dominated stream in the Wasatch Mountains of northern Utah, is subjected to increasing development and demands on water in the Snyderville Basin and adjacent areas. In this study, streamflow and specific conductance measured at three U.S. Geological Survey streamgages on East Canyon Creek were used to estimate daily baseflow for water years 2011–22. Trends in these estimates and correlations with climate data from two Natural Resource Conservation Service snow telemetry (SNOTEL) stations within the Snyderville Basin above East Canyon Reservoir, were quantified and reported. Peak annual streamflow also was assessed for flood potential on the study reach of East Canyon Creek. The hydrograph separations showed consistent baseflow indices among all sites, with a larger baseflow component during the fall–spring period (September–April; baseflow indices approximately equal to [≈] 0.751–0.835) and smaller component during the summer period (May–August; baseflow indices ≈ 0.428–0.532). In-stream specific conductance during spring (February–April) was influenced by road salt application, limiting the utility of the hydrograph separation approach. Annual streamflow and climate data were evaluated for trends using the nonparametric Mann–Kendall test, with inconclusive results. Related tests for trends, the Seasonal and Regional Kendall tests, were used to evaluate data at monthly timesteps and indicated a decreasing trend in total streamflow and baseflow at all streamgages. The rank-based Kendall’s tau test for correlation was used to measure the ordinal association with climatic data at co-located SNOTEL stations. Total streamflow and baseflow were strongly correlated with precipitation and snow-water equivalent. By incorporating a predictive regression model, the nonparametric Theil–Sen line, these correlations could support the development of streamflow forecast models using climate data from SNOTEL stations. Such models would provide water managers with tools to help make proactive decisions, such as reservoir or water reclamation releases and curtailment of withdrawals, in response to regional drought or varying snowpack and spring runoff in a given year.

Utah↗