Predicting effects of plantation expansion on streamflow regime for catchments in Australia

摘要

The effect of plantations on mean annual streamflow is well understood and,there are robust methods available for assessing the impact. Plantationsalso affect streamflow regime, leading to reductions in low flow andincreased number of zero-flow days. Understanding changes in streamflowregime following plantation expansion is important for developing waterresources and environmental flow strategy. This study evaluated the impactsof plantations on streamflow regime from 15 catchments in Australia. Theselected catchments range in size from 0.6 to 1136 km2 and representdifferent climatic conditions and management practices. The catchments haveat least 20 yr and in most cases 35 yr of continuous daily streamflowdata and well documented plantation records. Catchments with perennialstreamflow in the pre-treatment periods showed relatively uniform reductionsin most flows after plantation expansions, whereas catchments with ephemeralstreamflow showed more dramatic reductions in low flows, leading to anincreased number of zero-flow days. The Forest Cover Flow Change (FCFC)model was tested using the data from the selected catchments and comparisonof predicted and observed flow duration curves showed that 14 of the 15catchments have coefficients of efficiency greater than 0.8. The resultsindicate that the model is capable of predicting plantation impacts onstreamflow regime.