University of California Water Resources Center

The objective of this project was to determine the impact of urbanization on the hydrologic characteristics of watersheds in the Berkeley Hills of central California. The initial approach was to calibrate three stream gaging station prior to the development of one watershed above one of these stations and to follow changes in hydrologic characteristics during and subsequent to development. Economic and political developments in 1974 and 1975 prevented the developer from building on the principal watershed. A summary of data on annual water yield, characteristics of flood peaks, sediment yield, and water quality for the three non-urban watersheds is presented.

A subproject completed during the study compared periodicity of streamflow in previously urbanized and non-urbanized watersheds in the Berkeley Hills. Two daily discharge peaks which lagged 1.5 hours behind two daily peaks in lawn irrigation were observed. Peak daily streamflow on the urbanized watershed was 10 times that of a similar non-urbanized watershed. The stream from the urbanized watershed flowed continuously throughout the year while the stream from the non-urbanized watershed ceased flowing from late July until mid-October.