This report presents the results of an investigation of the effect of urban growth on the streamflow regimen of Permanente Creek in Mountain View, Santa Clara County, Calif. The data available did not permit a complete study of all hydrologic aspects, but there is conclusive evidence that the volume of storm runoff produced by rainfall on the valley floor has increased substantially as a result of urbanization. In 1945, storm runoff from the 5.12-square mile project area was insufficient to balance channel losses, and the streamflow entering the project area in the Permanente Creek channel was greater than that leaving the area. If, however, total outflow from the project area is considered to be the sum of the streamflow leaving the area plus channel seepage in the area, the ratio of total outflow to inflow was 1:18. By 1958, storm runoff from the project area was far in excess of channel losses and the ratio of total outflow to inflow was 1:70. This increase in outflow is attributed to the fact that urban development during the period 1945 to 1958 increased the extent of impervious surface in the project area from about 4 percent to 19 percent.
The effect of urban growth in other basins in Santa Clara County should be investigated before any attempt is made to project the quantitative results of this study to other areas in the county.
Additional publication details
USGS Numbered Series
Effect of urban growth on streamflow regimen of Permanente Creek, Santa Clara County, California
Water Supply Paper
U.S. Govt. Print. Off.,
1 v. (issued as seperate chapters) :ill. ;24 cm. ;18 p.