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Potentiometric surface in the Central Oklahoma (Garber-Wellington) aquifer, Oklahoma, 2009

A study of the hydrogeology of the Central Oklahoma aquifer was started in 2008 to provide the Oklahoma Water Resources Board (OWRB) hydrogeologic data and a groundwater flow model that can be used as a tool to help manage the aquifer. The 1973 Oklahoma water law requires the OWRB to do hydrologic investigations of Oklahoma's aquifers (termed 'groundwater basins') and to determine amounts of water that may be withdrawn by permitted water users. 'Maximum annual yield' is a term used by OWRB to describe the total amount of water that can be withdrawn from a specific aquifer in any year while allowing a minimum 20-year life of the basin (Oklahoma Water Resources Board, 2010). Currently (2010), the maximum annual yield has not been determined for the Central Oklahoma aquifer. Until the maximum annual yield determination is made, water users are issued a temporary permit by the OWRB for 2 acre-feet/acre per year. The objective of the study, in cooperation with the Oklahoma Water Resources Board, was to study the hydrogeology of the Central Oklahoma aquifer to provide information that will enable the OWRB to determine the maximum annual yield of the aquifer based on different proposed management plans. Groundwater flow models are typically used by the OWRB as a tool to help determine the maximum annual yield. This report presents the potentiometric surface of the Central Oklahoma aquifer based on water-level data collected in 2009 as part of the current (2010) hydrologic study. The U.S. Geological Survey (USGS) Hydrologic Investigations Atlas HA-724 by Christenson and others (1992) presents the 1986-87 potentiometric-surface map. This 1986-87 potentiometric-surface map was made as part of the USGS National Water-Quality Assessment pilot project for the Central Oklahoma aquifer that examined the geochemical and hydrogeological processes operating in the aquifer. An attempt was made to obtain water-level measurements for the 2009 potentiometric-surface map from the wells used for the 1986-87 potentiometric-surface map. Well symbols with circles on the 2009 potentiometric-surface map (fig. 1) indicate wells that were used for the 1986-87 potentiometric-surface map.

Scientific Investigations Map

An interim report on Sacramento River Chinook disease: A virus-like disease of Chinook salmon

An annually recurring disease among chinook salmмом ( Oncorhynchus tahawytscha ) FINGERLINGs at the National Fish Hatchery at Coleman, California, was reported by Ross, Pelnar, and Rucker (1960). They presented results of experimental investigation of the disease which established that the etiologic agent was filterable, highly virulent, and resistant to antibiotics and some of the more common chemicals, and that it was apparently not transmitted in salmon product-used as food, as was shown for a virus disease of sockeye salmon ( O. merka ) by Guenther, watson, and Rucker (T559). Also, Ross and his co-workers (1960) indicated a relation between temperature and incidence of the disease, and speculated on the possibility of the agent's being a virus.

Progressive Fish-Culturist

Surface-water hydrology of Honey Lake Valley, Lassen County, California, and Washoe County, Nevada

Honey Lake Valley straddles the state line of California and Nevada, about 35 miles north of Reno; about three-fourths of the area is in California. In this report, Honey Lake Valley (also referred to as the "basin") includes the entire area within the hydrographic boundary (fig. 1). Susanville, Calif., in the northwest part of the basin, is the largest town. Population is increasing rapidly both in the Susanville area and in the Reno area of adjacent Washoe County, Nev. Both Lassen and Washoe Counties have identified water resources in Honey Lake Valley as a possible source to meet their needs for future development. An important component of an assessment of the availability of additional long-term supply is an appraisal of surface-water resources. The U.S. Geological Survey, in cooperation with the California Department of Water Resources and the Nevada Division of Water Resources, began a hydrologic assessment of the area in 1987. The study was primarily an appraisal of ground-water resources, but it also included an assessment of surface-water resources. The purpose of this map report is to present the results of the surface-water assessment, including (1) a broad overview of surface-water conditions in the basin, (2) an estimate of mean annual streamflow to the valley floor, and (3) an evaluation of the characteristics of Honey Lake. This report will be republished by the U.S. Geological Survey as a Hydrologic-Investigations Atlas. Results of this study related to ground-water resources of the basin are discussed in a separate report (Handman and others, 1990) and are summarized in a short "Water Fact Sheet" by Handman (1990).

California, Nevada

U.S. Geological Survey middle Rio Grande basin study; proceedings of the third annual workshop, Albuquerque, New Mexico, February 24-25, 1999

Approximately 40 percent (about 600,000 people) of the total population of New Mexico lives within the Middle Rio Grande Basin, which includes the City of Albuquerque. Ongoing analyses of the central portion of the Middle Rio Grande Basin by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque and other agencies have shown that ground water in the basin is not as readily accessible as earlier studies indicated. A more complete characterization of the ground-water resources of the entire Middle Rio Grande Basin is hampered by a scarcity of data in the northern and southern areas of the basin. The USGS Middle Rio Grande Basin study is a 5-year effort by the USGS and other agencies to improve the understanding of the hydrology, geology, and land-surface characteristics of the Middle Rio Grande Basin. The primary objective of this study is to improve the understanding of the water resources of the basin. Of particular interest is to determine the extent of hydrologic connection between the Rio Grande and the Santa Fe Group aquifer. Additionally, ground-water quality affects the availability of water supplies in the basin. Improving the existing USGS-constructed ground-water flow model of the Middle Rio Grande Basin will integrate all the various tasks that improve our knowledge of the various components of the Middle Rio Grande water budget. Part of this improvement will be accompanied by extended knowledge of the aquifer system beyond the Albuquerque area into the northern and southern reaches of the basin. Other improvements will be based on understanding gained through process-oriented research and improved geologic characterization of the deposits. The USGS and cooperating agencies will study the hydrology, geology, and land-surface characteristics of the basin to provide the scientific information needed for water-resources management and for managers to plan for water supplies needed for a growing population. To facilitate exchange of information among the scientists working on the Middle Rio Grande Basin study, yearly technical meetings have been held for each of the first 3 years of the anticipated 5-year study. These meetings provide an opportunity to present research results and plan new field efforts. This report documents the results of research presented at the third annual technical workshop held in Albuquerque, New Mexico, February 24-25, 1999. The report is organized into this introduction and five chapters that focus on Middle Rio Grande Basin study investigations in progress in the Middle Rio Grande Basin. The first chapter describes geographic data and analysis efforts in the basin. The second chapter details work being done on the hydrogeologic and geologic framework of the basin. The third chapter describes studies on ground-water recharge in the basin. The fourth chapter provides details on the research on the ground-water flow system in the basin, including modeling efforts. The fifth chapter is devoted to an overview of New Mexico District Cooperative Program studies in the basin. The information in this report presents preliminary results of an evolving study. As the study progresses and individual projects publish their results in more detail, the USGS hopes to expand the scientific basis needed for management decisions regarding the Middle Rio Grande Basin.

Open-File Report

Summary of the Georgia Agricultural Water Conservation and Metering Program and evaluation of methods used to collect and analyze irrigation data in the middle and lower Chattahoochee and Flint River basins, 2004-2010

Since receiving jurisdiction from the State Legislature in June 2003 to implement the Georgia Agricultural Water Conservation and Metering Program, the Georgia Soil and Water Conservation Commission (Commission) by year-end 2010 installed more than 10,000 annually read water meters and nearly 200 daily reporting, satellite-transmitted, telemetry sites on irrigation systems located primarily in southern Georgia. More than 3,000 annually reported meters and 50 telemetry sites were installed during 2010 alone. The Commission monitored rates and volumes of agricultural irrigation supplied by groundwater, surface-water, and well-to-pond sources to inform water managers on the patterns and amounts of such water use and to determine effective and efficient resource utilization. Summary analyses of 4 complete years of irrigation data collected from annually read water meters in the middle and lower Chattahoochee and Flint River basins during 2007-2010 indicated that groundwater-supplied fields received slightly more irrigation depth per acre than surface-water-supplied fields. Year 2007 yielded the largest disparity between irrigation depth supplied by groundwater and surface-water sources as farmers responded to severe-to-exceptional drought conditions with increased irrigation. Groundwater sources (wells and well-to-pond systems) outnumbered surface-water sources by a factor of five; each groundwater source applied a third more irrigation volume than surface water; and, total irrigation volume from groundwater exceeded that of surface water by a factor of 6.7. Metered irrigation volume indicated a pattern of low-to-high water use from northwest to southeast that could point to relations between agricultural water use, water-resource potential and availability, soil type, and crop patterns. Normalizing metered irrigation-volume data by factoring out irrigated acres allowed irrigation water use to be expressed as an irrigation depth and nearly eliminated the disparity between volumes of applied irrigation derived from groundwater and surface water. Analysis of per-acre irrigation depths provided a commonality for comparing irrigation practices across the entire range of field sizes in southern Georgia and indicated underreporting of irrigated acres for some systems. Well-to-pond systems supplied irrigation at depths similar to groundwater and can be combined with groundwater irrigation data for subsequent analyses. Average irrigation depths during 2010 indicated an increase from average irrigation depths during 2008 and 2009, most likely the result of relatively dry conditions during 2010 compared to conditions in 2008 and 2009. Geostatistical models facilitated estimation of irrigation water use for unmetered systems and demonstrated usefulness in redesigning the telemetry network. Geospatial analysis evaluated the ability of the telemetry network to represent annually reported water-meter data and presented an objective, unbiased method for revising the network.

Georgia

Groundwater conditions in Utah, spring of 2015

This is the fifty-second in a series of annual reports that describe groundwater conditions in Utah. Reports in this series, published cooperatively by the U.S. Geological Survey and the Utah Department of Natural Resources, Division of Water Rights, and the Utah Department of Environmental Quality, Division of Water Quality, provide data to enable interested parties to maintain awareness of changing groundwater conditions. This report, like the others in the series, contains information on well construction, groundwater withdrawals from wells, water-level changes, precipitation, streamflow, and chemical quality of water. Information on well construction included in this report refers only to new wells constructed for withdrawal of groundwater. Supplementary data are included in reports of this series only for those years or areas that are important to a discussion of changing groundwater conditions and for which applicable data are available. This report includes individual discussions of selected significant areas of groundwater development in the State for calendar year 2014. Most of the reported data were collected by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights, and the Utah Department of Environmental Quality, Division of Water Quality. This report is also available online at http://www.waterrights.utah.gov/techinfo/ and http://ut.water.usgs.gov/publications/GW2015.pdf. Groundwater conditions in Utah for calendar year 2013 are reported in Burden and others (2014) and are available online at http://ut.water.usgs.gov/publications/GW2014.pdf. The water-level change maps in this report show the difference between water levels measured in the same well at two distinct times: in the spring of 1985 and the spring of 2015. Throughout the state, many groundwater levels were near their peak in or around 1985 following a multiple-year period of above average precipitation in the early 1980s. Conversely, consecutive years of significant drought have contributed to low groundwater levels in 2015. For these reasons, the difference between 1985 and 2015 groundwater levels may not accurately portray long-term changes in an aquifer. An evaluation of water-level trends should also include consideration of the annual water-level measurement plots provided for each of the major areas of groundwater development in this report.

Utah

Summary of fluvial-sediment studies in Ohio, through 1987

The U.S. Geological Survey, in cooperation with other Federal, State, and local agencies, has been collecting fluvial sediment data from Ohio streams since April 1950. This report summarizes the data collected for the period April 1950 through 1987. In addition, trends in annual suspended-sediment discharge in Ohio streams are examined and discussed, and a technique is presented for estimating discharge at ungaged points on Ohio streams. (USGS)

Water-Resources Investigations Report

Regional draft-storage relationships for central and western Upper Peninsula of Michigan

Regional draft-storage relationships for central and western Upper Peninsula of Michigan are presented in this report. Storage requirements for the 5- and 20-year recurrence intervals were determined using the frequency-mass curve method and daily discharge records from 15 gaging stations. The relationships will be useful in making preliminary estimates of development potential and inc comparing the development possibilities of different streams. Carryover storage was investigated and was found to be unnecessary at draft rates of less than 50 percent of the mean annual flow. Carryover storage requirements are presented for the gaging station Middle Branch Escanaba River near Ishpeming.

Michigan

Seepage investigations of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2006-13

Seepage investigations were conducted annually by the U.S. Geological Survey from 1988 to 1998 and from 2004 to 2013 along a 64-mile reach of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, as part of the Mesilla Basin monitoring program. Results of studies conducted from 2006 to 2013 are presented in this report. Seepage investigations were conducted over a period of 1–2 days in February of each year, during low-flow conditions in the non-irrigation season. During the seepage investigations, discharge was measured at as many as 24 sites along the Rio Grande and as many as 20 inflow sites within the study reach. Net seepage gain or loss was computed for each subreach by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be significant when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. Study reaches during 2006 to 2013 ranged from 20.2 to 64 miles in length, and seepage losses ranged from 8.2 ± 3.1 to 47.9 ± 8.2 cubic feet per second.

New Mexico;Texas

Simulation of water-quality data at selected stream sites in the Missouri River Basin, Montana

Modification of sampling programs at some water-quality stations in the Missouri River basin in Montana has eliminated the means by which solute loads have been directly obtained in past years. To compensate for this loss, water-quality and streamflow data were statistically analyzed and solute loads were simulated using computer techniques. Functional relationships existing between specific conductance and solute concentration for monthly samples were used to develop linear regression models. The models were then used to simulate daily solute concentrations using daily specific conductance as the independent variable. Once simulated, the solute concentrations, in milligrams per liter, were transformed into daily solute loads, in tons, using mean daily streamflow records. Computer output was formatted into tables listing simulated mean monthly solute concentrations, in milligrams per liter, and the monthly and annual solute loads, in tons, for water years 1975-78.

Montana

Statistical analysis and evaluation of water-quality data for selected streams in the coal area of east-central Montana

To document and evaluate existing conditions of water quality prior to proposed coal development in east-central Montana, water-quality data were collected at 23 sites on selected streams from October 1975 through September 1981. The data were statistically summarized and regression equations were developed to define relationships between water-quality variables. Where applicable, measured water-quality conditions were compared to various water-use standards. Measured concentrations of dissolved solids ranged from 145 to 12,200 milligrams per liter. Concentrations commonly exceeded 1,000 milligrams per liter and thereby present a high to very high salinity hazard for irrigation. Streamflow of the area contains predominantly sodium and sulfate ions and generally constitutes a medium to very high sodium hazard for irrigation during base flow. The water in most streams is generally adequate for livestock consumption during base flow. Concentrations of suspended sediment were extremely variable and had a direct correlation to water discharge. Measured suspended-sediment concentrations ranged from 4 to 23 ,000 milligrams per liter. Sediment-transport curves were developed for 18 of the study sites. Mean annual suspended-sediment loads were determined at five sites using the flow-duration, sediment-transport curve method. Mean annual sediment loads ranged from 1,010 to 72,7000 tons. (USGS)

Water-Resources Investigations Report

Contributions to economic geology (short papers and preliminary reports), 1915: Part I. - metals and nonmetals except fuels

This volume is the thirteenth of a series that includes Bulletins 213, 225, 260, 285, 315, 340, 380, 430, 470, 530, 540, and 580, "Contributions to economic geology" for 1902, 1903, 1904, 1905, 1906 (Pt. I), 1907 (Pt. I), 1908 (Pt. I), 1909 (Pt. I), 1910 (P t. I), 1911 (Pt. I) , 1912 (Pt. I), and 1913 (Pt. I), respectively . These bulletins are prepared primarily to insure prompt publication of the economic results of investigations made by the United States Geological Survey. Beginning with the present volume the year included in the title will be the year of publication 1 instead of the year in which the field work reported was done. This volume is therefore dated 1915, and there will be no volume entitled "Contributions to economic geology, 1914." As the subtitle indicates, the papers included are of two classes -(1) short papers giving comparatively detailed description of occurrences that have economic interest but are not of sufficient importance to warrant a more extended description; (2) preliminary reports on economic investigations the results of which are to be published later in more detailed form. These papers are such only as have a direct economic bearing, all topic of purely scientific interest being excluded. Each paper has been issued as an advance chapter as soon as it was ready. Brief abstracts of the publications of the year are given in the annual report of the Director. The complete list of Survey publications affords, by means of finding list of subjects and of authors, further aid in ascertaining the extent of the Survey's work in economic geology. Since 1905 the annual economic bulletin has been printed in two parts, the second part comprising paper on mineral fuels. These volumes for 1906, 1907, 190 , 1909, 1910, 1911, 1912, and 1913 are Bulletins 316, 341, 381, 431, 471, 531, 541, and 581. Bulletin 621 forms Part II of the "Contributions" for 1915. The reports on work in Alaska have been printed in a separate series since 1904, the volume so far issued being Bulletins 259, 284, 314, 345, 379, 442, 480, 520, 542, 592, and 622.

Bulletin

Alluvial diamond resource potential and production capacity assessment of the Central African Republic

In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflict concerns. This meeting was supported later in 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberly Process Certification Scheme (KPCS) was ratified and signed by diamond-producing and diamond-importing countries. Over 70 countries were included as members of the KPCS at the end of 2007. To prevent trade in "conflict diamonds" while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging. The objective of this study was (1) to assess the naturally occurring endowment of diamonds in the Central African Republic (potential resources) based on geological evidence, previous studies, and recent field data and (2) to assess the diamond-production capacity and measure the intensity of mining activity. Several possible methods can be used to estimate the potential diamond resource. However, because there is generally a lack of sufficient and consistent data recording all diamond mining in the Central African Republic and because time to conduct fieldwork and accessibility to the diamond mining areas are limited, two different methodologies were used: the volume and grade approach and the content per kilometer approach. Estimates are that approximately 39,000,000 carats of alluvial diamonds remain in the eastern and western zones of the CAR combined. This amount is roughly twice the total amount of diamonds reportedly exported from the Central African Republic since 1931. Production capacity is calculated to be 840,000 carats per year, a number that is nearly twice the 450,000 carats per year reported annually by the Central African Republic. The difference in the two numbers reflects the lack of sufficient data on diamond resource grades, worker productivity, and the number and locations of sites being worked.

Scientific Investigations Report

Determination of base-flow characteristics at selected streamflow-gaging stations on the Mad River, Ohio

This report describes the results of a study to estimate characteristics of base flow and sustained ground-water discharge at five streamflow-gaging stations on the Mad River in Ohio. The five streamflow-gaging stations are located at Zanesfield, near Urbana, at St. Paris Pike (at Eagle City), near Springfield, and near Dayton. The median of the annual-mean base flows, determined by means of hydrograph separation, ranged from 0.64 (ft3/s)/mi2 (cubic feet per second per square mile) at Zanesfield to 0.74 (ft3/s)/mi2 at St. Paris Pike. The median percentage of annual total streamflow attributed to base flow ranged from 61.8 percent at Zanesfield to 76.1 percent near Urbana. Estimates of an upper limit (or threshold) at which base flows can be considered to be composed predominately of sustained ground-water discharge were made by constructing and analyzing base- flow-duration curves. The sustained ground-water discharges (base flows less than or equal to the estimated sustained ground-water-discharge thresholds) are assumed to originate from ground-water- flow systems that are minimally affected by seasonal climatic changes. The median sustained ground- water discharge ranged from 0.11 (ft3/s)/mi2 at Zanesfield to 0.26 (ft3/s)/mi2 at St. Paris Pike (at Eagle City) and near Springfield. The median sustained ground-water discharge, expressed as a percentage of the median annual-mean base flow, ranged from 17.2 percent at Zanesfield to 38.6 percent near Springfield.

Water-Resources Investigations Report

Water levels and selected water-quality conditions in the Mississippi River Valley alluvial aquifer in Eastern Arkansas, 2008

During the spring of 2008, the U.S. Geological Survey, in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey, measured 670 water levels in 659 wells completed in the Mississippi River Valley alluvial aquifer in eastern Arkansas. Groundwater levels are affected by groundwater withdrawals resulting in potentiometric-surface depressions. In 2008, the lowest water-level altitude was 69 feet above National Geodetic Vertical Datum of 1929 in the center of Arkansas County. The highest water-level altitude was 288 feet above National Geodetic Vertical Datum of 1929 in northeastern Clay County on the west side of Crowleys Ridge. Two large depressions in the potentiometric surface are located in Arkansas, Lonoke, and Prairie Counties and west of Crowleys Ridge in Craighead, Cross, Lee, Monroe, Poinsett, St. Francis, and Woodruff Counties. The elongated depression in Arkansas, Lonoke, and Prairie Counties has two areas that have changed in horizontal area or depth when compared to previous conditions of the aquifer. The area in Arkansas County in the southeastern half of the depression has not expanded horizontally from recent years, although the center of the depression has deepened. The area in Lonoke and Prairie Counties in the northwestern half of the depression has not expanded and water level in the deeper part of the depression has risen. In Lonoke and Prairie Counties in the northwestern half of the depression, the 90-foot contour shown on the 2006 potentiometric-surface map is not shown on the 2008 potentiometric-surface map. Along the west side of Crowleys Ridge, the area enclosed by 140-foot contour in Cross and Poinsett Counties has expanded further south into Cross County. The 130-foot contour in Poinsett County expanded north in 2008. The 130-foot contour is shown in Cross County, which was not evident in previous years. The 130-foot contour in St. Francis, Monroe, and Woodruff Counties in 2006 is not shown on the 2008 potentiometric-surface map. A map showing the difference in water level was constructed using 595 differences in water levels measured in 585 wells during 2008 and 2004. The difference in measured water levels from 2004 to 2008 ranged from -20.6 feet to 25.9 feet, with a mean of -1.6 feet. The largest decline of -20.6 feet occurred in Randolph County and the largest rise of 25.9 feet occurred in Prairie County. Out of the 595 differences, 442 were declines (74.3 percent), 10 were no difference (values of 0.0 ft) (1.7 percent), and 143 were rises (24.0 percent). Five areas are dominated by declines that are west of Crowleys Ridge; in eastern Craighead County; in southern Mississippi and Crittenden Counties; in eastern Lonoke and western Prairie Counties; and in Arkansas, Ashley, Chicot, Desha, Drew, and Lincoln Counties. Long-term water-level changes were evaluated using hydrographs from 173 wells in the Mississippi River Valley alluvial aquifer for the period 1984 to 2008. The mean annual rise or decline in water level for the entire study area was -0.38 feet per year (ft/yr) with a range of -4.86 to 0.58 ft/yr. Independence and White Counties are the only counties with a mean annual rise from 1984 to 2008. Mean annual declines between -0.50 ft/yr and 0.00 ft/yr occurred in Arkansas, Chicot, Clay, Craighead, Crittenden, Drew, Greene, Jefferson, Mississippi, Monroe, Phillips, Poinsett, Prairie, Pulaski, Randolph, and Woodruff Counties. Mean annual declines between -1.00 ft/yr and -0.50 ft/yr occurred in Ashley, Desha, Jackson, Lee, Lincoln, and St. Francis Counties. Mean annual declines between -1.50 ft/yr and -1.00 ft/yr occurred in Cross and Lonoke Counties. The analysis of long-term water-level changes in Arkansas, Lonoke, and Prairie Counties shows the elongation of the depression in these three counties. Arkansas and Prairie Counties have two different rates of annual decline for the two hydrographs shown for each county. Water levels in the two we

Scientific Investigations Report

Hydrologic and hydraulic analyses of selected streams in Stark County, Ohio

To update and expand a part of the Federal Emergency Management Agency Flood Insurance Study, the U.S. Geological Survey, the Muskingum Watershed Conservancy District, and the Stark County Commissioners began a cooperative study. The study consisted of hydrologic and hydraulic analyses for selected reaches of 14 streams in Stark County, Ohio: Broad-Monter Creek, Chatham Ditch, East Branch Nimishillen Creek, Fairhope Ditch, Firestone Ditch, Hayden Ditch, Middle Branch Nimishillen Creek, Middle Branch Nimishillen Creek Tributary Number 1, Nimishillen Creek, Reemsnyder Ditch, Sherrick Run, unnamed stream, West Branch Nimishillen Creek, and Zimber Ditch. The study totaled nearly 50 miles of stream reaches. Instantaneous peak streamflows for floods with 10-, 4-, 2-, 1-, and 0.2-percent and 1-percent plus annual exceedance probabilities were estimated using historical streamflow data from the streamgages Nimishillen Creek at North Industry, Ohio (U.S. Geological Survey station number 03118500), and Middle Branch Nimishillen Creek at Canton, Ohio (U.S. Geological Survey station number 03118000), regional flood regression equations, and streamflow urbanization techniques. The annual exceedance probability streamflows were then used in a Hydrologic Engineering Center-River Analysis System step-backwater model to determine water-surface profiles, flood-inundation boundaries for the 10-, 4-, 2-, 1-, and 0.2-percent and 1-percent plus annual exceedance probability floods, and a regulatory floodway along a selected reach of each stream. Model input included DEM-derived cross sections supplemented with field surveys of open channel cross sections and hydraulic structures, field estimates of roughness values, and annual exceedance probability flood estimates from regional regression equations and historical streamflow data. Flood-inundation boundaries were mapped for the 1- and 0.2-percent annual exceedance probability floods and a regulatory floodway for each stream reach.

Ohio