Some effects of urbanization on streamflow records in a small watershed inthe lower Fraser Valley, BC

Times series of monthly, mean daily and maximum instantaneous streamflows w ere examined for changes which may be associated with urbanization within t he Nicomekl watershed in the lower Eraser Valley of British Columbia, Canad a. An adjacent watershed, the Salmon which has had much less urbanization, provided a comparison. In these low lying watersheds which receive heavy wi nter precipitation even slight increases in runoff could lead to increased flooding problems. Urbanization is relatively new in this area and though l and use changes due to urbanization are not yet extensive, statistically si gnificant increases in streamflow were detected. Continued urbanization cau sing increased runoff may generate increased flooding problems in the futur e.