Development and Integration of Sub‐hourly Rainfall–Runoff Modeling Capability Within a Watershed Model

Development and Integration of Sub‐hourly Rainfall–Runoff Modeling Capability Within a Watershed Model

0.00 Avg rating0 Votes
Article ID: iaor20108200
Volume: 24
Issue: 15
Start Page Number: 4505
End Page Number: 4527
Publication Date: Dec 2010
Journal: Water Resources Management
Authors: , , , , ,
Keywords: sensitivity analysis, water resources
Abstract:

Increasing urbanization changes runoff patterns to be flashy and instantaneous with decreased base flow. A model with the ability to simulate sub‐daily rainfall–runoff processes and continuous simulation capability is required to realistically capture the long‐term flow and water quality trends in watersheds that are experiencing urbanization. Soil and Water Assessment Tool (SWAT) has been widely used in hydrologic and nonpoint sources modeling. However, its subdaily modeling capability is limited to hourly flow simulation. This paper presents the development and testing of a sub‐hourly rainfall–runoff model in SWAT. SWAT algorithms for infiltration, surface runoff, flow routing, impoundments, and lagging of surface runoff have been modified to allow flow simulations with a sub‐hourly time interval as small as one minute. Evapotranspiration, soil water contents, base flow, and lateral flow are estimated on a daily basis and distributed equally for each time step. The sub‐hourly routines were tested on a 1.9 km2 watershed (70% undeveloped) near Lost Creek in Austin Texas USA. Sensitivity analysis shows that channel flow parameters are more sensitive in sub‐hourly simulations (Δt=15 min) while base flow parameters are more important in daily simulations (Δt=1 day). A case study shows that the sub‐hourly SWAT model reasonably reproduces stream flow hydrograph under multiple storm events. Calibrated stream flow for 1 year period with 15 min simulation (R 2=0.93) shows better performance compared to daily simulation for the same period (R 2=0.72). A statistical analysis shows that the improvement in the model performance with sub‐hourly time interval is mostly due to the improvement in predicting high flows. The sub‐hourly version of SWAT is a promising tool for hydrology and non‐point source pollution assessment studies, although more development on water quality modeling is still needed.

Reviews

Required fields are marked *. Your email address will not be published.