Flood data for the Sacramento River and Butte Basin, Sacramento Valley, California, 1980-90

Abstract

Floodflows and peak stages of floods were measured and channel cross sections were surveyed at sites along the Sacramento River and in Butte Basin, Sacramento Valley, California, during 1980-90 to document magnitudes of flooding and channel changes. The study reach extends from rivermile 200 near Hamilton City to rivermile 134 near Meridian. Data were collected for each flood at about 70 sites that include streamflow gages, crest-stage gages, bridges and road overflows on State Highway 162 east of Butte City, and locations of historical high-water marks. Six cross sections of the river between rivermiles 193.7 near Big Chico Creek and 183.3 near Ordbend were surveyed annually during calendar years 1981-84 and 1986-90. Floodflows (peak flow 157,000 cubic feet per second) almost equaled the design flow capacity of the river at Butte City on March 2, 1983, when the peak stage of 93.0 feet was 5 feet below the top of the levee. This was the largest flood recorded at Butte City during 1980-90. The most recent flood occurred February 18-19, 1986, when the peak stage in the river at Butte City was 92.0 feet and the peak flow was 145,000 cubic feet per second. Butte Basin is an agricultural area on the flood plain east of the Sacramento River (fig. 1) between Big Chico Creek and Meridian. Rice is the principal crop, but orchards and row crops also are cultivated in the area. Much of the basin is a waterfowl-wintering area that is enhanced by flooding. Changes in the distribution of flows across the flood plain are caused by farming activities, growth or clearing of vegetation, and roadway and bridge construction (Blodgett and Stiehr, 1974). During periods of flooding on the Sacramento River between Big Chico Creek and Meridian (fig. 1), flows inundate Butte Basin. Levees on the left (east) bank of the river downstream from rivermile 176 near Glenn prevent flooding into Butte Basin; however,