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Title: A DEM-based Watershed Model with Spatial Hortonian Infiltration and Ruh-Off/On

Author
item MENG, H - COLORADO STATE UNIVERSITY
item Green, Timothy
item SALAS, J - COLORADO STATE UNIVERSITY
item Ahuja, Lajpat

Submitted to: Trans American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2005
Publication Date: 12/5/2005
Citation: Meng, H., Green, T.R., Salas, J.D., Ahuja, L.R. 2005. A DEM-based watershed model with spatial hortonian infiltration and ruh-off/on. Trans American Geophysical Union, 86 (52), Fall Meeting Supplement, Abstract H13H-1400.

Interpretive Summary: A physically based, distributed rainfall-runoff-runon model was developed for event-based studies of dynamic watershed processes, including space-time patterns of state variables (e.g., soil profile water storage) and fluxes (e.g., overland flow and infiltration). A routing hierarchy for dynamic runoff and runon is defined over all DEM grid cells using the D-infinity terrain algorithm. Ponding time is computed to handle variable rainfall intensity, the Green-Ampt model is used to calculate infiltration, and the kinematic wave model is used to route Hortonian hillslope runoff 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 was first tested against theoretical solutions for idealized overland plane with satisfactory results. After a sensitivity analysis to identify the most significant calibration parameters, the model was calibrated and verified using rainfall and channel streamflow data collected from USDA-ARS Walnut Gulch experimental watershed. Finally, we will demonstrate applications of the model for simulating space-time patterns of fluxes and state variables within a watershed.

Technical Abstract: A physically based, distributed rainfall-runoff-runon model was developed for event-based studies of dynamic watershed processes, including space-time patterns of state variables (e.g., soil profile water storage) and fluxes (e.g., overland flow and infiltration). A routing hierarchy for dynamic runoff and runon is defined over all DEM grid cells using the D-infinity terrain algorithm. Ponding time is computed to handle variable rainfall intensity, the Green-Ampt model is used to calculate infiltration, and the kinematic wave model is used to route Hortonian hillslope runoff 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 was first tested against theoretical solutions for idealized overland plane with satisfactory results. After a sensitivity analysis to identify the most significant calibration parameters, the model was calibrated and verified using rainfall and channel streamflow data collected from USDA-ARS Walnut Gulch experimental watershed. Finally, we will demonstrate applications of the model for simulating space-time patterns of fluxes and state variables within a watershed.