| Abstract: | ABSTRACT: In the south-central interior of British Columbia, the summer and fall of 1987 were very dry. Streamflow was extremely low throughout the region, and an extended rainless period coincided with the onset of the winter dormant period. During a five-day rainless period from October 9 to October 13, which should have been a period of declining streamflow in all watersheds, 19 of 31 small forested watersheds having suitable natural flow record experienced increasing discharge. The data is reviewed and analyzed with an initial attempt made to explain the streamflow changes among the various watersheds quantitatively. The only explanation for the widespread increases in streamflow in the region during this dry period is that greatly reduced transpiration, as the vegetation went dormant, permitted increased volumes of water in the soil to drain into surface streams rapidly enough to be recorded as increased discharge in 61 percent of the study streams. |
