Analysis of two retention parameter estimation methods for curve number methodology on stream flow prediction
2011 (English)In: Ecosystem services in soil and water researchFocus on Soils and Water Symposium: Programme and Abstracts / [ed] Maria Kahlert & Annemieke Gärdenäs, 2011, 56-56 p.Conference paper, Abstract (Refereed)
The balance between water use for hydropower and irrigation, sustaining ecosystem services and preventing flood risk is essential to consider in water management for sustainable use. One rising concern is the conflict between the environment and agriculture mainly in lowland areas, where total base flows are abstracted for irrigation without compromising ecological conservation. Hence, it is important to understand the water balance and quantify the dominant components in a watershed to allocate water for all purposes.
Soil and Water Assessment Tool (SWAT) model was used to understand the hydrological process of the Upper Awash River Basin with the emphasis on analyzing surface runoff generation using the Soil Conservation Service (SCS) curve number method. SWAT incorporates two methods for estimating the retention parameter (S) for SCS curve number method; allowing S to vary with soil profile moisture content (SM) and to let S vary with accumulated plant evapotranspiration (PT). The PT method being more dependent on forcing data than soil data provides another dimension of applicability for data limited watersheds. The results were analyzed by visual comparison of the observed and simulated hydrographs and model performance measures. The hydrographs comparison indicated that the PT method was better in peak flow prediction while SM method outperformed in simulating the low flows. The performance measures (Nash-Sutcliffe Efficiency, Coefficient of Determination and Percent Bias) indicate better prediction by PT method. While the methods agree on predicting the hydrographs, they contradict in the annual water balance assessments. After evapotranspiration, base flow is the dominant component in SM method whereas surface runoff is the foremost in PT method. The results from the PT method agree with the outcome discussed in previous study. Furthermore, it has the advantage of governing by a single parameter that could be calibrated separately to control the base flow and surface runoff contribution to the total flow.
The analysis shows that care must be taken in selecting a way for quantifying, especially for ungauged catchments where validation of model result is unattainable.
Place, publisher, year, edition, pages
2011. 56-56 p.
Sustainable water use, water balance components, SWAT, retention parameter
IdentifiersURN: urn:nbn:se:kth:diva-109734OAI: oai:DiVA.org:kth-109734DiVA: diva2:583745
The symposium "Ecosystem services in soil and water research", Focus on Soils and Water, 7-9 June 2011 in Uppsala, Sweden.
QC 201306282013-01-082013-01-082013-06-28Bibliographically approved