Grantee Research Project Results
1998 Progress Report: Scaling Up Spatially Distributed Hydrologic Models of Semi-Arid Watersheds
EPA Grant Number: R824784Title: Scaling Up Spatially Distributed Hydrologic Models of Semi-Arid Watersheds
Investigators: Tarboton, David G. , Cooley, K. , Seyfried, M. , Hanson, C. L , Flerchinger, Gerald N , Neale, C.M. U. , Slaughter, C. W.
Institution: Utah State University
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1995 through September 1, 1998 (Extended to April 30, 2000)
Project Period Covered by this Report: October 1, 1997 through September 1, 1998
Project Amount: $330,000
RFA: Water and Watersheds (1995) RFA Text | Recipients Lists
Research Category: Watersheds , Water
Objective:
The purpose of this project is to understand interacting watershed processes over a range of scales in the Reynolds Creek Experimental Watershed (RCEW) in southwest Idaho. The project is a collaborative hydrologic modeling and measurement project involving Utah State University and the USDA Agricultural Research Service Northwest Watershed Research Center. The approach consists of the development of a spatially distributed modeling framework that accounts for spatial variability in topography, vegetation, and soils to facilitate physically realistic spatial integration of the complete water balance at a range of scales.Progress Summary:
Work this year has consisted of data analysis and model development. The modeling framework being developed includes components to represent snow drifting and melt, infiltration, runoff generation, and evapotranspiration. Each component is tested individually against measurements, as well as when assembled together against integrated and patterns of spatially distributed measurements. Methods to extend the physical models that so far have been well tested at small to larger scales also are being developed. In this respect, a new approach has been developed for the parameterization of the subgrid variability of snow, based upon depletion curves that relate snow water equivalence and snow-covered area. This extends the Utah Energy Balance (UEB) snow accumulation and melt model allowing it to be applied over larger areas, with larger model elements.The distributed modeling includes the comparison of approaches at multiple scales and levels of detail. These consist of explicitly distributed hydrologic modeling at each grid cell derived from a digital elevation data, lumped modeling, using the National Weather Service model, and semidistributed modeling using an adaptation of TOPMODEL, applied to subwatersheds within the study area. The explicitly distributed hydrologic model uses radiation as input at each grid cell, computed from topography. Surface runoff is generated by infiltration-excess or saturation-excess mechanisms. Subsurface flow is modeled using a one-dimensional unsaturated flow model, with lateral subsurface flow computed based upon either topographic slope or hydraulic gradient. Evapotranspiration is modeled using a sparse canopy energy balance model. The adaptation of TOPMODEL includes the Utah Energy Balance snowmelt model, with the new subgrid parameterization for snow variability based upon depletion curves, mentioned earlier.
High-resolution imagery acquired using the Utah State University airborne multispectral video/radiometer remote-sensing system is being used to develop GIS layers of vegetation parameters such as leaf area index and plant height and type. Ground-based measurements have been used to develop the necessary relationships. The distributed modeling aims to quantify the value of this information in improving outputs from hydrologic models. Thermal imagery also acquired from this system provides a spatially distributed check upon energy balance model performance.
Future Activities:
Future work will include completion of the modeling and analysis under way at Reynolds Creek, with application to larger subwatersheds within Reynolds Creek Experimental Watershed. Alternative model components that represent different levels of complexity and parameterization will be evaluated. It is anticipated that this work will lead to a better understanding of the spatial variability and scale dependence of hydrologic processes in this watershed. These results can be generalized to other watersheds in the semi-arid mountainous western United States.Journal Articles on this Report : 2 Displayed | Download in RIS Format
Other project views: | All 20 publications | 8 publications in selected types | All 7 journal articles |
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Type | Citation | ||
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Luce CH, Tarboton DG, Cooley KR. The influence of the spatial distribution of snow on basin-averaged snowmelt. Hydrological Processes 1998;12(10-11):1671-1683. |
R824784 (1998) R824784 (Final) |
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Luce CH, Tarboton DG, Cooley KR. Sub-grid parameterization of snow distribution for an energy and mass balance snow cover model. Hydrological Processes 1999;13(12-13):1921-1933. |
R824784 (1998) R824784 (Final) |
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Supplemental Keywords:
hydrology, snowmelt, watershed modeling., RFA, Scientific Discipline, Water, Geographic Area, Water & Watershed, Hydrology, State, Environmental Monitoring, Wet Weather Flows, Watersheds, EPA Region, scaling, collaborative hydrologic modeling, spatially distributed hydaulic models, water balance, Idaho (ID), streams, arid watersheds, climate change, vegetation, Region 8, infiltration, aquatic ecosystems, remotely sensed data, Reynolds Creek Experimental Watershed, semi-arid watersheds, snowmelt, climate variabilityRelevant Websites:
http://www.engineering.usu.edu/dtarb/Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.