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At least 109 records · Page 6Linked to original sources
USGS2016

Peak-flow frequency analyses and results based on data through water year 2011 for selected streamflow-gaging stations in or near Montana: Chapter C in Montana StreamStats

Chapter C of this Scientific Investigations Report documents results from a study by the U.S. Geological Survey, in cooperation with the Montana Department of Transportation and the Montana Department of Natural Resources, to provide an update of statewide peak-flow frequency analyses and results for Montana. The purpose of this report chapter is to present peak-flow frequency analyses and results for 725 streamflow-gaging stations in or near Montana based on data through water year 2011. The 725 streamflow-gaging stations included in this study represent nearly all streamflowgaging stations in Montana (plus some from adjacent states or Canadian Provinces) that have at least 10 years of peak-flow records through water year 2011. For 29 of the 725 streamflow-gaging stations, peak-flow frequency analyses and results are reported for both unregulated and regulated conditions. Thus, peak-flow frequency analyses and results are reported for a total of 754 analyses. Estimates of peak-flow magnitudes for 66.7-, 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities are reported. These annual exceedance probabilities correspond to 1.5-, 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals.

Montana↗
USGS1995

Streamflow, ground-water recharge and discharge, and characteristics of surficial deposits in Buzzards Bay Basin, southeastern Massachusetts

Streamflow measurements at 14 low-flow partial-record stations and two discontinued streamflow-gaging stations were related to concurrent streamflows at six long-term streamflow-gaging stations to estimate streamflows at selected flow durations from 50 to 99 percent for water years 1967-91. At low flows, stream discharge per square mile generally increased with increasing percentage of subbasin underlain by stratified-drift deposits. At the 70-, 90-, and 99-percent flow durations, subbasins underlain primarily by stratified-drift deposits had stream discharges per square mile at least 2, 4, and 8 times greater, respectively, than subbasins underlain primarily by till and bedrock deposits. Streamflow measured three times at the Paskamanset River showed that streamflows downstream of municipal pumped wells increased at a lower rate per unit drainage area than streamflows upstream of the pumped wells. When pumpage from wells near the river was added to measured streamflow at the most downstream station, the sum was similar to the potential streamflow at the station if its streamflow per unit area was the same as that upstream from the pumped wells. Mean ground-water recharge and discharge rates were computed from continuous records of daily mean discharge during water years 1967-91 for six streamflow-gaging stations in southeastern Massachusetts and Rhode Island. Estimates of mean ground-water recharge were 19.7 to 22.6 inches per year for stations with drainage areas primarily underlain by till and bedrock deposits, and 23.8 to 25.2 inches per year for stations with drainage areas primarily underlain by stratified-drift deposits. During drought years, annual ground-water recharge can be less than 50 percent of the mean ground-water recharge rate for water years 1967-91. Estimates of ground-water discharge rates generally were 1 to 4 inches per year less than estimates of ground-water recharge rates. Ground-water discharge-duration curves were calculated from hydrograph separation of streamflow records at the six continuous streamflow-gaging stations for water years 1967-91. When streamflows were less than the median streamflow (50-percent duration), ground-water discharges averaged 85.7 percent of the total streamflow at the six streamflow-gaging stations. Ground-water discharges were estimated at the 14 low-flow partial-record stations and two discontinued streamflow-gaging stations by multiplying streamflows at the selected flow durations from 50 to 99 percent for water years 1967-91 by 85.7 percent. Data on surficial deposits in the basin were obtained by drilling 10 wells, by conducting 12 seismic-refraction surveys, and by collecting well log data for 313 wells from consulting firms and the Massachusetts Department of Environmental Management. These data indicated that a few minor corrections could be made to existing saturated thickness maps for stratified-drift deposits in Buzzards Bay Basin. Few well logs were detailed enough to estimate transmissivities; thus existing transmissivity maps were not updated for stratified-drift deposits in the basin.

Massachusetts↗
USGS1984

Generalized skew coefficient for flood frequency computations for the State of Hawaii

In 1976, the Hydrology Committee of the U.S. Water Resources Council estimated a generalized skew coefficient for flood frequency computations of -0.05 for the State of Hawaii. This value is the average of 30 stream gaging stations with 25 or more years of record through water year 1973. This report updates the generalized skew coefficient for the State of Hawaii to -0.14. It is the average of 68 stream gaging stations with 25 or more years of record. (USGS)

Water-Resources Investigations Report↗
USGS2004

Long-Term Oceanographic Observations in Western Massachusetts Bay Offshore of Boston, Massachusetts: Data Report for 1989-2002

This data report presents long-term oceanographic observations made in western Massachusetts Bay at two locations: (1) 42 deg 22.6' N., 70 deg 47.0' W. (Site A, 33 m water depth) from December 1989 through December 2002 (figure 1), and (2) 42 deg 9.8' N., 70 deg 38.4' W. (Site B, 21 m water depth) from October 1997 through December 2002. Site A is approximately 1 km south of the new ocean outfall that began discharging treated sewage effluent from the Boston metropolitan area into Massachusetts Bay on September 6, 2000. These long-term oceanographic observations have been collected by the U.S. Geological Survey (USGS) in partnership with the Massachusetts Water Resources Authority (MWRA) and with logistical support from the U.S. Coast Guard (USCG - http://www.uscg.mil). This report presents time series data through December 2002, updating a similar report that presented data through December 2000 (Butman and others, 2002). In addition, the Statistics and Mean Flow sections include some new plots and tables and the format of the report has been streamlined by combining yearly figures into single .pdfs. Figure 1 (PDF format) The long-term measurements are planned to continue at least through 2005. The long-term oceanographic observations at Sites A and B are part of a USGS study designed to understand the transport and long-term fate of sediments and associated contaminants in the Massachusetts bays. (See http://woodshole.er.usgs.gov/project-pages/bostonharbor/ and Butman and Bothner, 1997.) The long-term observations document seasonal and inter-annual changes in currents, hydrography, and suspended-matter concentration in western Massachusetts Bay, and the importance of infrequent catastrophic events, such as major storms or hurricanes, in sediment resuspension and transport. They also provide observations for testing numerical models of circulation. This data report presents a description of the field program and instrumentation, an overview of the data through summary plots and statistics, and the data in NetCDF and ASCII format for the period December 1989 through December 2002 for Site A and October 1997 through December 2002 for Site B. The objective of this report is to make the data available in digital form and to provide summary plots and statistics to facilitate browsing of the long-term data set.

Data Series↗
USGS2018

Guidelines for determining flood flow frequency — Bulletin 17C

Accurate estimates of flood frequency and magnitude are a key component of any effective nationwide flood risk management and flood damage abatement program. In addition to accuracy, methods for estimating flood risk must be uniformly and consistently applied because management of the Nation’s water and related land resources is a collaborative effort involving multiple actors including most levels of government and the private sector. Flood frequency guidelines have been published in the United States since 1967, and have undergone periodic revisions. In 1967, the U.S. Water Resources Council presented a coherent approach to flood frequency with Bulletin 15, “A Uniform Technique for Determining Flood Flow Frequencies.” The method it recommended involved fitting the log-Pearson Type III distribution to annual peak flow data by the method of moments. The first extension and update of Bulletin 15 was published in 1976 as Bulletin 17, “Guidelines for Determining Flood Flow Frequency” (Guidelines). It extended the Bulletin 15 procedures by introducing methods for dealing with outliers, historical flood information, and regional skew. Bulletin 17A was published the following year to clarify the computation of weighted skew. The next revision of the Bulletin, the Bulletin 17B, provided a host of improvements and new techniques designed to address situations that often arise in practice, including better methods for estimating and using regional skew, weighting station and regional skew, detection of outliers, and use of the conditional probability adjustment. The current version of these Guidelines are presented in this document, denoted Bulletin 17C. It incorporates changes motivated by four of the items listed as “Future Work” in Bulletin 17B and 30 years of post-17B research on flood processes and statistical methods. The updates include: adoption of a generalized representation of flood data that allows for interval and censored data types; a new method, called the Expected Moments Algorithm, which extends the method of moments so that it can accommodate interval data; a generalized approach to identification of low outliers in flood data; and an improved method for computing confidence intervals. Federal agencies are requested to use these Guidelines in all planning activities involving water and related land resources. State, local, and private organizations are encouraged to use these Guidelines to assure uniformity in the flood frequency estimates that all agencies concerned with flood risk should use for Federal planning decisions. This revision is adopted with the knowledge and understanding that review of these procedures will be ongoing. Updated methods will be adopted when warranted by experience and by examination and testing of new techniques.

Georgia↗
USGS2014

Subsidence (2004-2009) in and near lakebeds of the Mojave River and Morongo groundwater basins, southwest Mojave Desert, California

Subsidence, in the vicinity of dry lakebeds, within the Mojave River and Morongo groundwater basins of the southwest Mojave Desert has been measured by Interferometric Synthetic Aperture Radar (InSAR). The investigation has focused on determining the location, extent, and magnitude of changes in land-surface elevation. In addition, the relation of changes in land-surface elevation to changes in groundwater levels and lithology was explored. This report is the third in a series of reports investigating land-surface elevation changes in the Mojave and Morongo Groundwater Basins, California. The first report, U.S. Geological Survey (USGS) Water-Resources Investigations Report 03-4015 by Sneed and others (2003), describes historical subsidence and groundwater-level changes in the southwest Mojave Desert from 1969 to 1999. The second report, U.S. Geological Survey Water-Resources Investigations Report 07-5097, an online interactive report and map, by Sneed and Brandt (2007), describes subsidence and groundwater-level changes in the southwest Mojave Desert from 1999 to 2004. The purpose of this report is to document an updated assessment of subsidence in these lakebeds and selected neighboring areas from 2004 to 2009 as measured by InSAR methods. In addition, continuous Global Positioning System (GPS)(2005-10), groundwater level (1951-2010), and lithologic data, if available, were used to characterize compaction mechanisms in these areas. The USGS California Water Science Center’s interactive website for the Mojave River and Morongo groundwater basins was created to centralize information pertaining to land subsidence and water levels and to allow readers to access available data and related reports online. An interactive map of land subsidence and water levels in the Mojave River and Morongo groundwater basins displays InSAR interferograms, subsidence areas, subsidence contours, hydrographs, well information, and water-level contours. Background information, including a basic description of the mechanics of land subsidence and InSAR, as well as a description of the study area, is presented within the Mojave Water Resources Interactive Map and report.

California↗
USGS2013

Estimation of missing water-level data for the Everglades Depth Estimation Network (EDEN), 2013 update

The Everglades Depth Estimation Network is an integrated network of real-time water-level gaging stations, a ground-elevation model, and a water-surface elevation model designed to provide scientists, engineers, and water-resource managers with water-level and water-depth information (1991-2013) for the entire freshwater portion of the Greater Everglades. The U.S. Geological Survey Greater Everglades Priority Ecosystems Science provides support for the Everglades Depth Estimation Network in order for the Network to provide quality-assured monitoring data for the U.S. Army Corps of Engineers Comprehensive Everglades Restoration Plan. In a previous study, water-level estimation equations were developed to fill in missing data to increase the accuracy of the daily water-surface elevation model. During this study, those equations were updated because of the addition and removal of water-level gaging stations, the consistent use of water-level data relative to the North American Vertical Datum of 1988, and availability of recent data (March 1, 2006, to September 30, 2011). Up to three linear regression equations were developed for each station by using three different input stations to minimize the occurrences of missing data for an input station. Of the 667 water-level estimation equations developed to fill missing data at 223 stations, more than 72 percent of the equations have coefficients of determination greater than 0.90, and 97 percent have coefficients of determination greater than 0.70.

Florida↗
USGS2019

Capacity and area of Grand Lake O’ the Cherokees, northeastern Oklahoma, 2009

In February 2017, the Grand River Dam Authority filed to relicense the Pensacola Hydroelectric Project with the Federal Energy Regulatory Commission. The predominant feature of the Pensacola Hydroelectric Project is Pensacola Dam, which impounds Grand Lake O’ the Cherokees (locally called Grand Lake) in northeastern Oklahoma. Identification of information gaps and assessment of project effects on stakeholders are central aspects of the Federal Energy Regulatory Commission relicensing process. Due to the natural changes to the reservoir over time, new capacity and area tables are needed periodically. The most recent complete capacity and area table was produced in 1940. Capacity and area tables identify the relations between the elevation of the water surface and the volume of water that can be impounded at each water surface elevation. This report (1) presents an updated capacity and area table for Grand Lake O’ the Cherokees for 2009, (2) describes the methods used to calculate the updated capacity and area values presented in the table, and (3) compares the updated capacity table to historical capacity tables produced from a survey in 1940 and from a hydrographic survey of the lake by the Oklahoma Water Resources Board in 2009. The new capacity values computed for Grand Lake O’ the Cherokees indicate that capacity at conservation pool elevation has decreased about 157,000 acre-feet or 10 percent since 1940 and capacity at top of dam elevation has decreased about 200,000 acre-feet or 8 percent since 1940. This difference in the capacities could be attributed to the advancements of technologies; the techniques used for surveying lakes have changed from the 1940 survey to the 2009 survey. Another possible reason for loss in capacity could be as time progresses, lakes like Grand Lake O’ the Cherokees slowly impound sediment carried by the rivers that feed into the lakes, thus diminishing the amount of water that the lake holds. The most recent survey used measured water depths and Global Position System collected electronically, but the methods used to collect data in 1940 are unknown. Due to the advancement of technology, the 2009 survey is likely more precise than the 1940 survey.

Oklahoma↗
USGS2024

Streamflow characteristics and trends in New Jersey, water years 1903–2017

As New Jersey’s population density remains high, so does its requirements for water management. Understanding the streamflow conditions throughout the state and how they may have changed over time is an important part of managing the water resources within the state. The New Jersey Department of Environmental Protection has many responsibilities related to protecting the environment and natural resources and among them is protecting the waters in the lakes, rivers, and streams of New Jersey for current and future use. To support this mission, the U.S. Geological Survey updated high- and low-streamflow statistics for 97 continuous-record streamgages and low-streamflow statistics for 719 partial-record streamgages throughout the state. The continuous-record streamgages included in the study had a minimum of 20 years of record, spanning from 1903 to 2017. This study is an update to previous studies that documented the high- and low-streamflow statistics for New Jersey streams in the 1970s and in 2005. The 1982 report by Gillespie and Schopp documented low-flow characteristics and flow duration for about 400 continuous and partial-record streamgages. The U.S. Geological Survey computed streamflow statistics including, but not limited to, maximum, minimum, and means for period of record, flow durations, nonexceedance high- and low-flow frequencies, base flow, runoff, peak-to-mean flow ratios, and September median streamflow. Overall, both high and low flows are generally increasing in New Jersey, though the results are not uniform across the State. Streamflow trends and changes to duration and frequency statistics can be influenced by local water use, in addition to climate variables. The resulting computations at some streamgages indicated considerable positive change while others showed considerable negative change. Water managers and regulators can use the data provided here and in the companion data release to assess individual stream reaches and watershed management areas to evaluate the available resources and changes, which may have developed during the periods for which streamflow statistics are available.

New Jersey↗
USGS1997

Water and salt balance of Great Salt Lake, Utah, and simulation of water and salt movement through the causeway

The water and salt balance of Great Salt Lake primarily depends on the amount of inflow from tributary streams and the conveyance properties of a causeway constructed during 1957-59 that divides the lake into the south and north parts. The conveyance properties of the causeway originally included two culverts, each 15 feet wide, and the permeable rock-fill material. During 1980-86, the salt balance changed as a result of record high inflow that averaged 4,627,000 acre-feet annually and modifications made to the conveyance properties of the causeway that included opening a 300-foot-wide breach. In this study, a model developed in 1973 by Waddell and Bolke to simulate the water and salt balance of the lake was revised to accommodate the high water-surface altitude and modifications made to the causeway. This study, done by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of State Lands and Forestry, updates the model with monitoring data collected during 1980-86. This report describes the calibration of the model and presents the results of simulations for three hypothetical 10-year periods. During January 1, 1980, to July 31, 1984, a net load of 0.5 billion tons of dissolved salt flowed from the south to the north part of the lake primarily as a result of record inflows. From August 1, 1984, when the breach was opened, to December 31,1986, a net load of 0.3 billion tons of dissolved salt flowed from the north to the south part of the lake primarily as a result of the breach. For simulated inflow rates during a hypothetical 10-year period resulting in the water-surface altitude decreasing from about 4,200 to 4,192 feet, there was a net movement of about 1.0 billion tons of dissolved salt from the south to the north part, and about 1.7 billion tons of salt precipitated in the north part. For simulated inflow rates during a hypothetical 10-year period resulting in a rise in water-surface altitude from about 4,200 to 4,212 feet, there was a net movement of about 0.2 billion tons of dissolved salt from the south to the north part and no salt was precipitated in the north part of the lake.

Utah↗
USGS2017

Water resources of Parowan Valley, Iron County, Utah

Parowan Valley, in Iron County, Utah, covers about 160 square miles west of the Red Cliffs and includes the towns of Parowan, Paragonah, and Summit. The valley is a structural depression formed by northwest-trending faults and is, essentially, a closed surface-water basin although a small part of the valley at the southwestern end drains into the adjacent Cedar Valley. Groundwater occurs in and has been developed mainly from the unconsolidated basin-fill aquifer. Long-term downward trends in groundwater levels have been documented by the U.S. Geological Survey (USGS) since the mid-1950s. The water resources of Parowan Valley were assessed during 2012 to 2014 with an emphasis on refining the understanding of the groundwater and surface-water systems and updating the groundwater budget. Surface-water discharge of five perennial mountain streams that enter Parowan Valley was measured from 2013 to 2014. The total annual surface-water discharge of the five streams during 2013 to 2014 was about 18,000 acre-feet (acre-ft) compared to the average annual streamflow of about 22,000 acre-ft from USGS streamgages operated on the three largest of these streams from the 1940s to the 1980s. The largest stream, Parowan Creek, contributes more than 50 percent of the annual surface-water discharge to the valley, with smaller amounts contributed by Red, Summit, Little, and Cottonwood Creeks. Average annual recharge to the Parowan Valley groundwater system was estimated to be about 25,000 acre-ft from 1994 to 2013. Nearly all recharge occurs as direct infiltration of snowmelt and rainfall on the Markagunt Plateau east of the valley. Smaller amounts of recharge occur as infiltration of streamflow and unconsumed irrigation water near the east side of the valley on alluvial fans associated with mountain streams at the foot of the Red Cliffs. Subsurface flow from the mountain block to the east of the valley is a significant source of groundwater recharge to the basin-fill aquifer. Groundwater flows from the high-altitude recharge areas downward toward the basin-fill aquifer in Parowan Valley. Almost all groundwater discharge occurs as withdrawals from irrigation wells in the valley with a small amount of discharge from phreatophytic evapotranspiration. Subsurface groundwater discharge to Cedar Valley is likely minimal. Withdrawals from wells during 2013 were about 32,000 acre-ft. The estimated withdrawals from wells from 1994 to 2013 have ranged from 22,000 to 39,000 acre-ft per year. Declining water levels are an indication of the estimated average annual decrease in groundwater storage of 15,000 acre-ft from 1994 to 2013. Groundwater and surface-water samples were collected from 46 sites in Parowan Valley and Cedar Valley near the town of Enoch during June 2013. Groundwater samples from 34 wells were submitted for geochemical analysis. The total dissolved-solids concentration in water from these wells ranged from 142 to 886 milligrams per liter. Results of stable isotope analysis of oxygen and deuterium from groundwater and surface-water samples indicate that most of the groundwater in Parowan Valley and in Cedar Valley near Enoch is similar in isotopic composition to water from mountain streams, which reflects meteoric water recharged in high-altitude areas east of the valley. In addition, results of stable isotope analysis of a subset of samples from wells located near Little Salt Lake may indicate recharge of precipitation that occurred during cooler climatic conditions of the Pleistocene Epoch.

Utah↗
USGS1980

Water-level monitoring along San Andreas and San Jacinto faults, southern California, during fiscal year 1980

Beginning in October 1976, a program of water-level monitoring of abandoned water wells was initiated in the Palmdale area with the purpose of identifying possible water-level changes premonitory to a major earthquake on the San Andreas fault. In October 1977, the program was extended southeastward along the rift zone to the Valyermo area. In November 1977, the monitoring of water wells along the San Jacinto fault was initiated with the expectation of experiencing a moderate size earthquake while monitoring was in progress. Currently over thirty wells are being monitored. Eleven wells are monitored continuously with Stevens Type F recorders, two of which have been modified to operate with the Caltech Remote Observatory Support Systems (TIMS). The remaining wells are probed weekly, or in some cases semi-weekly or daily, by volunteers. We are endeavoring to improve the volunteer program by increasing the frequency of measurements and simplifying the procedure to minimize measurement errors. Weekly water-level data are displayed on computer-generated hydrographs for each well. Rainfall and earthquakes are plotted on the graphs for direct comparison with water levels. The hydrographs are updated and reviewed weekly. Weekly hydrographs are also prepared from recorder charts on two wells maintained by W. R. Moyle, Jr., of the U.S. Geological Survey, Water Resources Division Office, Laguna Niguel, California. A M5.5 earthquake occurred on 25 February 1980, between the Buck Ridge and San Jacinto strands of the San Jacinto fault zone, about 8 miles east-southeast of Anza. This is the largest earthquake which has occurred on the faults within our monitoring network. The Stevens recorder chart for well number 11S/6E-3N4 located in Borrego Valley about 20 miles southeast of the epicenter indicates that, during a period of about four hours on 21 February, the water level rose 1.5 to 1.6 feet and returned to its prior level. This is one of the most remarkable short-term water-level fluctuations observed during our monitoring program; it occurred about 88 hours prior to the earthquake. This well has been monitored since October 1977 and has had a Stevens recorder since October 1978. Long-term water levels have been remarkably steady compared to those in other wells we are monitoring. This well shows a strong response to earth tides. The Stevens record on a second well in Borrego Valley (11S/6E-1C1) showed a much smaller (0.1 foot) spike in water level at the same time as the spike in well number 11S/6E-3N4. Other continuously recording wells in Anza and Ocotillo Wells showed no identifiable water-level anomalies. The two wells in Borrego Valley which showed possible strain-induced water-level spikes appear to be more sensitive to earth tides than wells in the same area which did not show spikes in water level. We cannot conceive of any nontectonic cause for the spike on the Stevens record of well 11S/6E3N4. A creep event on the Coyote Creek fault about four miles from the well is one possibility. Because the spikes in the two wells in Borrego Valley are unique for the long-term record of these wells, they may represent precursors to the 25 February earthquake. Local seismic activity was also recorded in water levels of the two wells in Borrego Springs with continuous water-level recorders. One well showed peculiar high frequency water-level fluctuations from 22 July to 21 August 1980; since then the record has appeared normal. Several wells in the Palmdale-Valyermo area have shown peculiar changes in water level within the past year or so. The long-term hydrograph of well number 5N/12W-4H1 shows the most unusual behavior. The well showed no response to the 1977 and very heavy 1978 rainstorms, yet began to rise in early 1979 and continued to rise through the dry season of 1979. By comparison, most wells show a more normal seasonal response to rainfall. Eight wells in the Palmdale-Valyermo area have shown water-level changes which are different than would have been predicted from the previous history of water-level changes and seasonal rainfall. A longer period of observation is required to determine whether the changes are anomalous. Changes in the strain pattern and other geophysical phenomena have also been observed in southern California during about the same period as the water-level changes. If the water-level changes are the result of tectonic strain, the mechanism and significance are unknown. However, it is interesting that five of the eight wells with possibly anomalous water-level changes have been identified as good strain meters based on their response to earth tides. Six wells showing an unexpected rise in water level are located west of the earthquake swarm which occurred in 1976-1977 (McNally et al, 1978), whereas the two which show water levels lower than would have been predicted are located east of the earthquake swarm.

California↗
USGS2018

Missouri StreamStats—A water-resources web application

The U.S. Geological Survey (USGS) maintains and operates more than 8,200 continuous streamgages nationwide. Types of data that may be collected, computed, and stored for streamgages include streamgage height (water-surface elevation), streamflow, and water quality. The streamflow data allow scientists and engineers to calculate streamflow statistics, such as the 1-percent annual exceedance probability flood (also known as the 100-year flood), the mean flow, and the 7-day, 10-year low flow, which are used by managers to make informed water resource management decisions, at each streamgage location. Researchers, regulators, and managers also commonly need physical characteristics (basin characteristics) that describe the unique properties of a basin. Common uses for streamflow statistics and basin characteristics include hydraulic design, water-supply management, water-use appropriations, and flood-plain mapping for establishing flood-insurance rates and land-use zones. The USGS periodically publishes reports that update the values of basin characteristics and streamflow statistics at selected gaged locations (locations with streamgages), but these studies usually only update a subset of streamgages, making data retrieval difficult. Additionally, streamflow statistics and basin characteristics are most often needed at ungaged locations (locations without streamgages) for which published streamflow statistics and basin characteristics do not exist. Missouri StreamStats is a web-based geographic information system that was created by the USGS in cooperation with the Missouri Department of Natural Resources to provide users with access to an assortment of tools that are useful for water-resources planning and management. StreamStats allows users to easily obtain the most recent published streamflow statistics and basin characteristics for streamgage locations and to automatically calculate selected basin characteristics and estimate streamflow statistics at ungaged locations.

Missouri↗
USGS1986

Potentiometric map of the Meridian-Upper Wilcox aquifer in Mississippi, fall 1983

The Meridian-upper Wilcox aquifer consists of the Meridian Sand member of the Tallahatta Formation and the uppermost sand beds of the Wilcox Group. Thickness of the aquifer ranges from 50 ft to 500 ft. Precipitation recharges the Meridian-upper Wilcox in the outcrop area, which extends from Benton County, MS, in the north to Clarke County, MS, in the south. The potentiometric map is based on water level measurements made in about 170 wells in the Meridian-upper Wilcox aquifer in October 1983, and on the approximate altitudes of water surfaces in some major streams. The contours show altitudes at which water levels would have stood in tightly cased unpumped wells. This map, the second in the series for the Meridian-upper Wilcox aquifer, updates a map that delineated the potentiometric surface of the aquifer in 1979.

Mississippi↗
USGS2023

Bathymetric contour maps, surface area and capacity tables, and bathymetric change maps for selected water-supply lakes in northeastern Missouri, 2021

Bathymetric data were collected at 12 water-supply lakes in northeastern Missouri by the U.S. Geological Survey (USGS) in cooperation with the Missouri Department of Natural Resources (MoDNR) and various local agencies, as part of a multiyear effort to establish or update the surface area and capacity tables for the surveyed lakes. The lakes were surveyed in March through May 2021. Ten of the lakes had been surveyed previously by the USGS, and the recent surveys were compared to the earlier surveys to document the changes in the bathymetric surface and capacity of the lakes. Bathymetric data were collected using a high-resolution multibeam mapping system mounted on a boat. Supplemental depth data at five of the lakes were collected in shallow areas with an acoustic Doppler current profiler on a remote-controlled boat. Data points from the various sources were exported at a gridded data resolution appropriate to each lake, either 0.82 foot, 1.64 feet, or 3.28 feet. Data outside the multibeam survey extent and greater than the surveyed water-surface elevation were obtained from data collected using aerial light detection and ranging (lidar) point cloud data. A linear enforcement technique was used to add points to the dataset in areas of sparse data (the upper ends of coves where the water was shallow or aquatic vegetation precluded data acquisition) based on surrounding multibeam and upland data values. The various point datasets were used to produce a three-dimensional triangulated irregular network surface of the lake-bottom elevations for each lake. A surface area and capacity table was produced from the three-dimensional surface for each lake showing surface area and capacity at specified lake water-surface elevations. Various quality-assurance tests were conducted to ensure quality data were collected with the multibeam, including beam angle checks and patch tests. Additional quality-assurance tests were conducted on the gridded bathymetric data from the survey, the bathymetric surface created from the gridded data, and the contours created from the bathymetric survey. If there were data from a previous bathymetric survey for a given lake, a bathymetric change map was generated from the elevation difference between the previous survey and the 2021 bathymetric survey data points. After reconciling any vertical datum disagreement between the previous survey data and the 2021 survey datum, coincident points between the surveys were identified, and a bathymetric change map was generated using the coincident point data. The mean elevation change between all repeat surveys at most lakes was positive, indicating sedimentation. Relative to previous surveys, the change in capacity at the primary spillway elevation ranged from a 7.7-percent decrease at Memphis Reservoir to a 3.9-percent increase at Old Lake (Bowling Green West). The mean bathymetric change ranged from 0.03 foot at Hazel Creek and 0.07 foot at Shelbina Lake and Bowling Green Reservoir (Jack Floyd Memorial Lake) to 0.63 at Memphis Lake (Lake Showme) and 0.88 at Memphis Reservoir. The time-averaged mean bathymetric change ranged from 0.002 foot per year at Hazel Creek Lake to 0.044 foot per year at Memphis Reservoir. The computed volumetric sedimentation rate generally ranged from 0.14 to 6.80 acre-feet per year at Shelbina Lake and Memphis Lake (Lake Showme), respectively; however, Forest Lake had a substantially larger sedimentation rate of 17.0 acre-feet per year. Some changes observed in some bathymetric change maps are believed to result from the difference in data collection equipment and techniques between the previous and present bathymetric surveys, whereas other erosional features around the perimeter of certain lakes may be the result of wave action during low-water years.

Missouri↗
USGS2025

Bathymetric contour maps, surface area and capacity tables, and bathymetric change maps for selected water-supply lakes in Missouri, 2022–23

Bathymetric data were collected at 13 water-supply lakes around the periphery of Missouri by the U.S. Geological Survey in cooperation with the Missouri Department of Natural Resources and various local agencies, as part of a multiyear effort to establish or update the surface area and capacity tables for the surveyed lakes. Surveys were carried out during the months of April and May in 2022 and 2023. All but two of the lakes had been surveyed previously by the U.S. Geological Survey, and the recent surveys were compared to the earlier surveys to document the changes in the bathymetric surface and capacity of the lake. Bathymetric data were collected using a high-resolution multibeam mapping system mounted on a boat. Supplemental depth data at three of the lakes were collected in shallow areas with an acoustic Doppler current profiler on a remote-controlled boat. Data points from the various sources were exported at a gridded data resolution appropriate to each lake, either 0.82 foot, 1.64 feet, or 3.28 feet. Data outside the multibeam survey extent and greater than the surveyed water-surface elevation were obtained from data collected using aerial light detection and ranging (lidar) point cloud data. A linear enforcement technique was used to add points to the dataset in areas of sparse data (the upper ends of coves where the water was shallow or aquatic vegetation precluded data acquisition) based on surrounding multibeam and upland data values. The various point datasets were used to produce a three-dimensional triangulated irregular network surface of the lake-bottom elevations for each lake. A surface area and capacity table was produced from the three-dimensional surface for each lake showing surface area and capacity at specified lake water-surface elevations. Various quality-assurance tests were conducted to ensure quality data were collected with the multibeam, including beam angle checks and patch tests. Additional quality-assurance tests were conducted on the gridded bathymetric data from the survey, the bathymetric surface created from the gridded data, and the contours created from the bathymetric survey.

Missouri↗
USGS1997

An algorithm for computing moments-based flood quantile estimates when historical flood information is available

This paper presents the expected moments algorithm (EMA), a simple and efficient method for incorporating historical and paleoflood information into flood frequency studies. EMA can utilize three types of at-site flood information: systematic stream gage record; information about the magnitude of historical floods; and knowledge of the number of years in the historical period when no large flood occurred. EMA employs an iterative procedure to compute method-of-moments parameter estimates. Initial parameter estimates are calculated from systematic stream gage data. These moments are then updated by including the measured historical peaks and the expected moments, given the previously estimated parameters, of the below-threshold floods from the historical period. The updated moments result in new parameter estimates, and the last two steps are repeated until the algorithm converges. Monte Carlo simulations compare EMA, Bulletin 17B 's [ United States Water Resources Council , 1982] historically weighted moments adjustment, and maximum likelihood estimators when fitting the three parameters of the log-Pearson type III distribution. These simulations demonstrate that EMA is more efficient than the Bulletin 17B method, and that it is nearly as efficient as maximum likelihood estimation (MLE). The experiments also suggest that EMA has two advantages over MLE when dealing with the log-Pearson type III distribution: It appears that EMA estimates always exist and that they are unique, although neither result has been proven. EMA can be used with binomial or interval-censored data and with any distributional family amenable to method-of-moments estimation.

Water Resources Research↗