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# Northern California Storms and Floods of January 1995

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### Index of Subjects



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## Introduction



## The Storms

Table 1.  Precipitation at selected sites in northern California, January 9--14, 1995



`----------------------------------------------------------------
Rain-gage site  24-hour        100-year, 24-hour,   Storm total,  
                precipitation  precipitation1       Jan. 9--14    
----------------------------------------------------------------
Carmel            7.5            5                    --          
Cloverdale        4.9            9                    16.5        
Eureka            1.97           6.5                  6.75        
Folsom            5.85           5                    9.11        
Jackson           3.31           6.5                  6.32        
Mt. Shasta        5.9            10                   14.85       
Placerville       4.13           7                    7.25        
Roseville         7.75           4.5                  11.05       
Ruth              4.37           10                   20.86       
Sacramento        4.45           4                    6.57        
Santa Rosa        2.8            6                    8.8         
Soquel            4.5            10                   12          
Ukiah             3.84           7                    12.47       
----------------------------------------------------------------`



## The Floods





Figure 1. Location of selected stream-gaging stations in northern California showing peak streamflows and recurrence intervals for January 1995 floods.



Figure 2. Gage heights for selected stream-gaging stations during January 1995.

Flooding in small basins was unusually rapid because of the high-intensity, short- duration microbursts of rainfall. Small streams, rather than the large rivers, caused most of the damage in the Central Valley. The Sacramento area was hard hit, especially the communities of Roseville and Rio Linda. Flooding along large rivers in the Central Valley was controlled by diversions and flood-control reservoirs that had large storage capacities available. Small streams and rivers in the coastal areas also caused widespread flooding.

More than 10 years of drought and low streamflows resulted in the accumulation of dense riparian vegetation in most stream channels. Flooding along the Russian River was due, in part, to the accumulation of vegetation and debris that had reduced the capacity of the stream channel. This reduced capacity resulted in higher water levels with less streamflow. For example, the water level at the stream-gaging station on the Russian River near Guerneville nearly reached the record high, but the streamflow was significantly less than that during a flood in 1986.



## The Response

Most measurements of water levels in streams are automated. In recent years, information compilation has been improved by use of Electronic Data Collection Platforms (DCP's). These platforms use automated earth-satellite telemetry for the immediate transmission of data from remote sites (fig. 3). Cellular telephones and modems also are being used to obtain timely information, but not all stream-gaging stations are equipped with this instrumentation. Currently (1995), 40 additional DCP's are being installed within California as part of the USGS and Department of Water Resources cooperative stream-gaging program.





Figure 3. The transmission, processing, and distribution of streamflow data using satellite and computer technology.

During the recent floods, the USGS was able to rapidly compile and disseminate near-realtime information for many of its gaging stations by using the telephone and computer networks. Also beginning this year, the USGS has begun making data available on the Internet through the California District "Home Page" at http://water.usgs.gov/lookup/get?cawater to provide the public and interested agencies with immediate access to flood data and other hydrologic data. During January 1995, most of this data was made available within hours of a flood peak.



## Reference

``



> from U.S. Department of the Interior, U.S. Geological Survey, Fact Sheet FS-062-95

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Last modified: 1330 8 MAY 95 ghc