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M. V. Johnson

Publications and source records attributed to M. V. Johnson.

7 recordsLinked to original sources
USGS1978

Map showing depth to water table, September 1976, and area inundated by the June 1975 flood, Helena Valley, Lewis and Clark County, Montana

Depth to water table, September 1976, and area inundated by the June 1975 flood in the Helena valley, Montana, are mapped on two sheets, Helena and East Helena 7.5-minute quadrangles, at scale 1:48,000. Depth to water table was mapped using water-level measurements from existing shallow observation wells and selected domestic wells, and from field reconnaissance of topography. A hydrograph shows water-level fluctuation in two wells located in different parts of the valley. Area inundated by the June 1975 flood was mapped from aerial photos along Prickly Pear and Tenmile Creeks and by field reconnaissance along Silver Creek. (Woodard-USGS)

Montana↗
USGS1978

Floods of June 4 and 12, 1976, at Culbertson, Montana

Runoff from rainfall caused flooding in the town of Culbertson, Montana, on June 4 and 12, 1976. Flood damage was mostly to business and residential structures within Culberston. Two small drainage contributed the peak flows, which at one site exceeded 1,200 cubic feet per second per square mile of contributing area. Flow from the Missouri River tributary No 5 at Culbertson consisted of flow through a pipe-arch at the State Highway 16 crossing and flow that overtopped the right bank of the main channel. Maximum combined pipe-arch and bypass flow for the June 12 flood was 1,30030 cubic feet per second. Flow from Diamond Creek consisted of flow through a culvert at the U.S. Highway 2 crossing west of Culbertson and flow that overtopped a road. Maximum combined culvert and bypass flow for the June 4 flood was 1,320 cubic feet per second. Failure of small dam increased the flow volume of the flood.

Open-File Report↗
USGS1977

Annual peak discharges from small drainage areas in Montana through September 1976

Annual peak discharge from small drainage areas is tabulated for 336 sites in Montana. The 1976 additions included data collected at 206 sites. The program which investigates the magnitude and frequency of floods from small drainage areas in Montana, was begun July 1, 1955. Originally 45 crest-stage gaging stations were established. The purpose of the program is to collect sufficient peak-flow data, which through analysis could provide methods for estimating the magnitude and frequency of floods at any point in Montana. The ultimate objective is to provide methods for estimating the 100-year flood with the reliability needed for road design. (Woodard-USGS)

Open-File Report↗
USGS1976

A method for estimating magnitude and frequency of floods in Montana

This report provides methods for estimating flood characteristics at most natural flow sites on rural streams in Montana. It also contains significant flood data and related information for many gaged sites on Montana streams. Frequency curves are provided for 442 gaged sites as defined by log-Pearson Type III analysis. To allow estimates at ungaged sites, mathematical equations relate the 2-, 5-, 10-, 25-, 50-, and 100-year flood magnitudes to basin characteristics. Drainage area, main channel slope, and mean annual precipitation were found to be the most significant estimating variables. Equations presented are limited to use on streams with drainage areas from about 0.1 to 2,600 square miles (0.3 to 6,700 square kilometres), with slope from about 5 to 1,200 feet per mile (1.5 to 366 metres per kilometre), and with precipitation from 10 to 100 inches (250 to 2,500 millimetres). Nomographs provide a simple graphical means of solving the estimating relations, and illustrative examples are presented.

Montana↗
USGS1976

Floods of May-July 1975 Along the Continental Divide in Montana

Extensive flooding occurred along both sides of the Continental Divide in Montana from May through July 1975. Runoff from above average snowpack at low altitudes combined with runoff from rainfall to cause floods in May. Snowmelt from high altitudes and above average rain in June caused flooding and sustained high flows into July. Federal and State agencies estimated flood damage at about $53,000,000. Peak stages, flow rates, and estimated frequencies were determined for 124 sites.

Open-File Report↗