Geology Reports⌕ Search

Geology topics

Charles Parrett

Publications and source records attributed to Charles Parrett.

46 records · Page 3Linked to original sources
USGS1985

A method for estimating mean and low flows of streams in national forests of Montana

Equations were developed for estimating mean annual discharge, 80-percent exceedance discharge, and 95-percent exceedance discharge for streams on national forest lands in Montana. The equations for mean annual discharge used active-channel width, drainage area and mean annual precipitation as independent variables, with active-channel width being most significant. The equations for 80-percent exceedance discharge and 95-percent exceedance discharge used only active-channel width as an independent variable. The standard error or estimate for the best equation for estimating mean annual discharge was 27 percent. The standard errors of estimate for the equations were 67 percent for estimating 80-percent exceedance discharge and 75 percent for estimating 95-percent exceedance discharge. (USGS)

Water-Resources Investigations Report↗
USGS1984

Floods of May 1978 in southeastern Montana and northeastern Wyoming

Heavy rain and some snow fell on previously saturated ground over southeastern Montana and northeastern Wyoming during May 16-19, 1978. The maximum amount of 7.60 inches within a 72-hour period observed at Lame Deer, Montana, set a record for the month of May in that region. Heavy flooding occurred in the drainages of the Yellowstone River and its tributaries as well as the Belle Fourche, Cheyenne, and North Platte Rivers. The previous maximum flood of record was exceeded at 48 gaged sites, and the 1-percent chance flood was equaled or exceeded at 24 sites. Flood damage was extensive, exceeding $33 million. Nineteen counties in the two States were declared major disaster areas. Mean daily suspended-sediment discharges exceeded previously recorded maximum mean daily values at four sites on the Powder River. The maximum daily suspended-sediment discharge of 2,810,000 tons per day occurred on May 20 at the Site Powder River near Arvada, Wyoming. (USGS)

Professional Paper↗
USGS1983

Mean annual runoff and peak flow estimates based on channel geometry of streams in southeastern Montana

Equations using channel-geometry measurements were developed for estimating mean runoff and peak flows of ungaged streams in southeastern Montana. Two separate sets of esitmating equations were developed for determining mean annual runoff: one for perennial streams and one for ephemeral and intermittent streams. Data from 29 gaged sites on perennial streams and 21 gaged sites on ephemeral and intermittent streams were used in these analyses. Data from 78 gaged sites were used in the peak-flow analyses. Southeastern Montana was divided into three regions and separate multiple-regression equations for each region were developed that relate channel dimensions to peak discharge having recurrence intervals of 2, 5, 10, 25, 50, and 100 years. Channel-geometery relations were developed using measurements of the active-channel width and bankfull width. Active-channel width and bankfull width were the most significant channel features for estimating mean annual runoff for al types of streams. Use of this method requires that onsite measurements be made of channel width. The standard error of estimate for predicting mean annual runoff ranged from about 38 to 79 percent. The standard error of estimate relating active-channel width or bankfull width to peak flow ranged from about 37 to 115 percent. (USGS)

Water-Resources Investigations Report↗
USGS1983

Mean annual runoff and peak flow estimates based on channel geometry of streams in northeastern and western Montana

Equations for estimating mean annual runoff and peak discharge from measurements of channel geometry were developed for western and northeastern Montana. The study area was divided into two regions for the mean annual runoff analysis, and separate multiple-regression equations were developed for each region. The active-channel width was determined to be the most important independent variable in each region. The standard error of estimate for the estimating equation using active-channel width was 61 percent in the Northeast Region and 38 percent in the West region. The study area was divided into six regions for the peak discharge analysis, and multiple regression equations relating channel geometry and basin characteristics to peak discharges having recurrence intervals of 2, 5, 10, 25, 50 and 100 years were developed for each region. The standard errors of estimate for the regression equations using only channel width as an independent variable ranged from 35 to 105 percent. The standard errors improved in four regions as basin characteristics were added to the estimating equations. (USGS)

Water-Resources Investigations Report↗
USGS1983

Flood estimates for ungaged streams in Glacier and Yellowstone National Parks, Montana

Estimates of 100-year discharges were made at 59 sites in Glacier National Park and 21 sites in Yellowstone National Park to assist the National Park Services in quantifying stream inflow and outflow in the Parks. The estimates were made using regression equations previously developed for Montana. The resulting 100-year discharges are listed in tables; the discharges ranged from 260 to 53,200 cu ft/s in Glacier National Park and from 110 to 27,900 cu ft/s in Yellowstone National Park. (USGS)

Montana, Wyoming↗
USGS1982

Floods of May 1981 in west-central Montana

Extensive flooding occurred in west-central Montana during May 22-23, 1981, as a result of a series of rainstorms. Flooding was particularly severe in the communities of East Helena, Belt, and Deer Lodge. Although no lives were lost, total flood damages were estimated by the Montana Disaster Emergency Services Division to be in excess of $30 million. Peak discharges were determined at 75 sites in the flooded area. At 25 sites the May 1981 peak discharge exceeded the computed 100-year frequency flood, and at 29 sites, where previous flow records are available, the May 1981 peak discharge exceeded the previous peak of record. (USGS)

Montana↗
USGS1981

Revised techniques for estimating magnitude and frequency of floods in Montana

Relations for estimating the flood magnitudes for ungaged sites in Montana have been updated. The State was divided into eight regions and separate multiple-regression equations for each region were developed that relate logarithms of annual flood magnitude to logarithms of basin characteristics for exceedance probabilities of 50, 20, 10, 4, 2, and 1 percent. The standard errors of estimate for an exceedance probability of 1 percent ranged from 39 to 58 percent in the western and central parts of the State and from 47 to 83 percent in the eastern part. The standard errors of estimate indicate a substantial improvement over previous studies. Techniques for transferring annual flood-frequency information at gaged sites to ungaged sites on the same stream have been updated. Included are curves relating flood-frequency information to drainage area for eight major streams in the State. Maximum known flood peaks in Montana are compared with estimated 1-percent-chance flood peaks and with national maximum known flood peaks. Values of flood discharges for selected exceedance probabilities and values of significant basin characteristics for all gaging stations used in the analysis are tabulated. Included are data for 339 stations in Montana and 34 nearby stations in Canada and adjoining States. (USGS)

Open-File Report↗
USGS1955

Annual peak discharges from small drainage areas in Montana through September 1980

Annual peak stage and discharge data have been collected and tabulated for crest-stage gaging sites in Montana. The crest-stage program was begun in July 1955 to investigate the magnitude and frequency of floods from small drainage areas. The program has expanded from 45 crest-stage gaging stations initially to 172 stations maintained in 1980. Data in the report are tabulated for the period of record. (USGS)

Open-File Report↗