SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Assessing environmental flow targets using pre-settlement land cover: A SWAT modeling application 
Authors:Zeiger, S.J. and J.A. Hubbart 
Volume (Issue):10(6) 
Article ID:791 
URL (non-DOI journals): 
Broad Application Category:hydrologic only 
Primary Application Category:land use change 
Secondary Application Category:hydrologic, pollutant and/or crop indices (or metrics) 
Watershed Description:228 km^2 Hinkson Creek, located in central Missouri, U.S. 
Calibration Summary: 
Validation Summary: 
General Comments: 
Abstract:Determining environmental flow requirements to sustain aquatic ecosystem health remains a challenge. The purpose of this research was to quantify the extent of current flow alterations relative to baseline hydrologic conditions of a simulated historic flow regime prior to anthropogenic flow disturbance (i.e., pre-settlement flows). Results allowed assessment of the efficacy of environmental flow targets based on pre-settlement land cover in a contemporary mixed-land-use catchment (i.e., urban, agricultural, and forested). Pre-settlement flows were simulated using the Soil and Water Assessment Tool (SWAT). Pre-settlement land cover, based on soil physical characteristics, was used to simulate pre-settlement flows with the SWAT model. Environmental flow targets were calculated for each flow element of a historic flow regime (magnitude, frequency, duration, timing, and rate of change). Urban (20% of watershed area) and agricultural development (42% of watershed area) were correlated to decreased median daily stream flow by 0.8 m3 s-1 (percent difference = -115%), increased maximum daily flow by 22 m3 s-1 (percent difference = 13%), and a 34% increase in daily flow variability. High flow frequency increased by 45–76% following development. Results highlight a need for consideration of environmental flow targets appropriate for watersheds already modified by existing land use, and point to a need for long-term, broad-scale, and persistent efforts to develop achievable environmental flow recommendations, particularly in rapidly urbanizing mixed-land-use watersheds. 
Keywords:environmental flows; ELOHA; ecohydrology;mixed-land-use hydrology; SWAT; EflowStats