How Watershed Management Affects Water Production? A Water Balance Sensitivity Approach

Document Type


Journal/Book Title/Conference

Utah State University Spring Runoff Conference


Logan, UT

Publication Date



Land cover changes such as afforestation, deforestation and agricultural intensification have impacts on surface runoff. The objective of this study is to address the question as to how watershed management and land cover impact water production from watersheds in Utah. In other words, how to assess the sensitivity of runoff to changes in land cover. The scale of interest is regional watersheds specified by USGS 8 digit Hydrologic Unit Code (HUC) subbasins. Twelve USGS 8 digit HUCs in Utah, with an average area of 4500 km2 were selected for this study. Within these subbasins we identified a total of 39 watersheds draining to USGS streamflow gages, chosen either from the USGS Hydroclimatic Climatic Data Network of gages that are minimally impacted by anthropogenic alterations, or to be representative of large areas within the chosen HUCs with long relatively continuous streamflow records. In each of these watersheds we examined trends in precipitation, temperature, snow and streamflow. We also examined land use and land cover information for these watersheds from the national land cover dataset, southwest regional GAP (SWReGAP) analyses and the Utah division of water resources water related land use inventory. We have developed a water balance approach that quantifies sensitivity of runoff production to changes in land cover based on differences in evapotranspiration from different land cover types. This water balance approach provides predictions of how water production from these Utah watersheds may change with land cover changes. By considering a range of potential evapotranspiration coefficients we provide water balance derived bounds on how streamflow could change given land cover changes. This study provides a basis for estimating the changes in water production due to land cover changes, so as to assist in the management of land and water resources.

This document is currently not available here.