A regional estimate of postfire streamflow change in California. Issue 2 (28th February 2016)

• Record Type: Journal Article
• Authors: Bart, Ryan R.
• Is Part Of: Water resources research. Volume 52:Issue 2(2016:Feb.)
• Page Start: 1465
• Page End: 1478
• Publication Date: 2016-02-28
• Subjects: streamflow -- watershed -- paired watershed -- mixed model -- regionalization -- fire -- California; Hydrology -- Periodicals; 333.91
• DOI: 10.1002/2014WR016553
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: The effect of fire on annual streamflow has been examined in numerous watershed studies, with some studies observing postfire increases in streamflow while other have observed no conclusive change. Despite this inherent variability in streamflow response, the management of water resources for flood protection, water supply, water quality, and the environment necessitates an understanding of postfire effects on streamflow at regional scales. In this study, the regional effect of wildfire on annual streamflow was investigated using 12 paired watersheds in central and southern California. A mixed model was used to pool and statistically examine the combined paired‐watershed data, with emphasis on the effects of percentage area burned, postfire recovery of vegetation, and postfire wetness conditions on postfire streamflow change. At a regional scale, postfire annual streamflow increased 134% (82%–200%) during the first postfire year assuming 100% area burned and average annual wetness conditions. Postfire response decreased with lower percentages of percentage area burned and during subsequent years as vegetation recovered following fire. Annual streamflow response to fire was found to be sensitive to annual wetness conditions, with postfire response being smallest during dry years, greatest during wet years, and slowly decreasing during very wet years. These findings provide watershed managers with a first‐order estimate for predicting postfire streamflow response in both gauged and ungauged watersheds. Key Points: Regional effect of fire on annual streamflow was estimated using a mixed model Annual streamflow in California increased following fire at regional scale Postfire streamflow change was sensitive to postfire wetness conditions