Evaluation of the Effects of Anthropogenic Activity on Streamflow in the Columbia211 River Basin

摘要

The primary objective of this study was to evaluate the macroscale hydrologic211u001eeffects of anthropogenic changes in vegetation on streamflow. This was 211u001eaccomplished by comparing streamflow predictions based on current and historical 211u001evegetation scenarios. The historical frame of reference was the early 1900's and 211u001ethe current frame of reference was the 1990's. Changes in vegetation were 211u001erepresented by the assignment of vegetation parameters extracted from spatial 211u001emaps of current and historical vegetation type and structural stage, where 211u001estructural stage is analogous to the condition and/or successional stage of 211u001eforest stands. The secondary study objective was to assess the sensitivity of 211u001epredicted changes in streamflow to the specification of vegetation parameters, 211u001esuch as vegetation rooting depth. The model parameter which controls the vertical 211u001eroot distribution profile was varied in small increments as a function of 211u001estructural stage and the resulting predicted current and historical scenario 211u001emonthly hydrographs were compared.