Abstract

Long-term streamflow relations with riparian gallery forest expansion, Oklahoma, USA
Track: Water Resources
Authors: Michael Wine

To determine how riparian gallery forest expansion affected streamflow, we classified a chronosequence of historical aerial photography covering a 78 km2 watershed equipped with a streamflow gauge. Here we show that in the Council Creek watershed in north-central Oklahoma, the baseflow component of streamflow increased from 1938-1992 during which time tree cover increased from 5% to 18% of the watershed area. During this period there were significant increasing trends in precipitation and evapotranspiration, but no significant trends in total streamflow. Stepwise regression indicated that relative to increases in precipitation, increases in forest cover were a better predictor of the observed baseflow increase. The method used in the study—relating an historical aerial photography chronosequence to existing long-term stream gauge data—proved to be an inexpensive, efficient, and effective in disproving our hypothesis that riparian gallery forest expansion would reduce baseflows.