Impacts of precipitation intensification on runoff, sediment yield, and plant available water in central Oklahoma

Authors: JOSHI, SANJEEV - University Of Oklahoma; Garbrecht, Jurgen; Brown, David; Zhang, Xunchang; Busteed, Phillip; XIAO, XIANMING - University Of Oklahoma

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 10/2/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary: Abstract only

Technical Abstract: Increasing trends in intense precipitation events forming the upper tail (above 90th percentile) of daily precipitation distributions have been reported during the last several decades across the United States. These trends have been used to formulate intensification scenarios representing future increments at heavy (90-95th percentile), very heavy (95-99th percentile), and extreme (> 99th percentile) thresholds of intense precipitation events. However, the impacts of intensification scenarios upon runoff, sediment transport, and plant available water in various agricultural practices remains poorly understood. Such investigations are crucial for building appropriate management plans across the Nation to address potential negative impacts of increased erosion, runoff, and crop loss in agricultural systems. In this study, we assess the impacts of projected precipitation intensification upon runoff, sediment yield, and plant available water using a baseline condition and three intensification scenarios, developed from a 200-repeat years synthetic daily precipitation record, for a location in central Oklahoma. Both the baseline and synthetic precipitation data are then used as climate inputs to the Water Erosion Prediction Project (WEPP) model to simulate soil erosion, runoff, sediment yield, and plant available water for conventional and no tillage agricultural practices. Preliminary results from this study show that annual sediment yield and runoff increased gradually from baseline conditions to high intensification scenarios, but only under conventional agricultural practices. Agricultural practices with conventional tillage also had substantially higher total runoff and sediment yields than those with no tillage, for the baseline condition and all three intensification scenarios. However, annual plant available water was approximately the same for baseline conditions and intensification scenarios in both practices. This study illustrates important implications of potential future precipitation intensification via the sensitivity of agricultural systems to impacts on runoff, sediment yield, and plant available water.