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United States Department of Agriculture

Agricultural Research Service

Title: Development and Testing of a Terrain-Based Hydrologic Model for Spatial Hortonian Infiltration and Run-Off/on

Authors
item Meng, Huan - COLORADO STATE UNIV/NOAA
item Green, Timothy
item Salas, Jose - COLORADO STATE UNIVERSITY
item Ahuja, Lajpat

Submitted to: Environmental Modelling & Software
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 29, 2007
Publication Date: April 11, 2008
Repository URL: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VHC-4RHXTK4-1&_user=4250348&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000052423&_version=1&_urlVersion=0&_userid=4250348&md5=2516fe523d3f69414c51068089aea09b
Citation: Meng, H., Green, T.R., Salas, J., Ahuja, L.R. 2008. Development and testing of a terrain-based hydrologic model for spatial hortonian infiltration and run-off/on . Environmental Modeling & Software. 23 (6): 794-812.

Interpretive Summary: Efficient numerical simulation of process interactions between infiltration and Hortonian runoff is needed to evaluate patterns within a watershed. A physically based, fully distributed rainfall-runoff model was developed for event-based studies of space-time watershed processes. A routing hierarchy is defined throughout all pixels over the watershed using the D-infinity contributing area algorithm, allowing for topographic convergence and divergence. The computation of ponding time is included to handle variable run-on and rainfall intensity. The Green-Ampt model is adopted to calculate surface infiltration, and the kinematic wave model is used to route overland and channel flow. The distributed rainfall-runoff model can handle input rainfall, soil parameters, and other watershed properties that vary in space and/or time. The model is first tested against analytical solutions for idealized overland planes with satisfactory results. After a sensitivity analysis to identify the most significant calibration parameters, it is then calibrated and verified using rainfall and streamflow data collected from the USDA-ARS Walnut Gulch experimental watershed. The model is provided as an open-source tool for space-time simulation and scaling of event-based Hortonian runoff and infiltration.

Technical Abstract: Efficient numerical simulation of process interactions between infiltration and Hortonian runoff is needed to evaluate patterns of internal state variables and fluxes within a watershed. A physically based, fully distributed rainfall-runoff model was developed for event-based studies of space-time watershed processes. A routing hierarchy is defined throughout all pixels over the watershed using the D-infinity contributing area algorithm, allowing for topographic convergence and divergence. The computation of ponding time is included to handle variable run-on and rainfall intensity. The Green-Ampt model is adopted to calculate surface infiltration, and the kinematic wave model is used to route Hortonian runoff and channel flow. The governing equations are solved numerically using an implicit finite difference scheme. The distributed rainfall-runoff model can handle input rainfall, soil parameters, and other watershed properties that vary in space and/or time. The model is first tested against analytical solutions for idealized overland planes with satisfactory results. After a sensitivity analysis to identify the most significant calibration parameters, it is then calibrated and verified using rainfall and streamflow data collected from the USDA-ARS Walnut Gulch experimental watershed. The coefficients of efficiency for runoff volume, peak flow, and time to peak flow with respect to calibration/verification are 0.95/0.75, 0.85/0.59, and 0.69/0.96, respectively. Example applications of the model show its potential for simulating internal states and fluxes. The model is provided as an open-source tool for space-time simulation and scaling of event-based Hortonian runoff and infiltration.

Last Modified: 7/25/2014