Study Reach.--Section 1 is about 650 ft upstream from gage.
Gage Location.--Lat 46°51'45", long 120°28'30", in NW1/4 sec.20, T.16N., R.19E., on right bank at Umtanum, 0.5 mile upstream from Umtanum Creek and 10 miles south of Ellensburg.
Drainage Area.--1,590 sq mi, approximately.
Gage Datum and Elevations of Reference Points.--Not available.
Stage, Discharge Measurements and Computed n-Values.--Gage heights were 38.98 ft at gage; 41.27 ft at section 1. Peak discharges was 27,700 cfs. on May 29, 1948.
| Date of Observation | Discharge (ft3/s) | Average Cross Section Area (ft2) | Hydraulic Radius (ft) | Mean Velocity (ft/s) | Slope | Coefficient of Roughness n |
|---|---|---|---|---|---|---|
| 5/29/1948 | 27714.8 | 2573.3 | 11.18 | 10.77 | 0.002955 | 0.036 |
Description of Channel.--Bed consists of gravel and boulders. Left bank is rock riprap with bushes. Right bank is mildly sloped and has some boulders, brush, and weed cover.
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://il.water.usgs.gov/proj/nvalues/db_barnes/sites/12484500.shtml[an error occurred while processing this directive]?
Page Contact Information: David Soong
Page Last Modified: December 19, 2012
