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Simulating interactions between saturated and unsaturated storage in a conceptual runoff model

Seibert, Jan and Rodhe, Allan and Bishop, Kevin (2003). Simulating interactions between saturated and unsaturated storage in a conceptual runoff model. Hydrological processes. 17:2, 379-390
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Official URL: http://www3.interscience.wiley.com/cgi-bin/fulltex...

Abstract

There is an increasing demand for modelling the fluxes of chemical constituents at the catchment scale. Conceptual runoff models provide a basis for such modelling tasks provided that they capture the essential hydrological processes. However, most conceptual models do not fully address interactions between unsaturated and saturated storage. This can lead to unrealistic simulations for watersheds with shallow groundwater, where a large part of the soil volume can contribute to both the unsaturated and the saturated storage depending on groundwater levels. Adding a small amount of water to the saturated storage will cause a significant amount of water stored in the unsaturated zone to change its status to ‘saturated’. The maximum volume of the unsaturated storage also decreases with rising groundwater levels, i.e., increasing saturated storage. In this study, a new model concept was proposed in which special emphasis was put on the interaction between saturated and unsaturated storage. The total storage was divided into two compartments, representing saturated and unsaturated storage, with a boundary moving up and down in response to the water budget of the compartments. Groundwater dynamics show a distinct pattern along the studied hillslope. Groundwater levels in an area close to the stream had dynamics similar to runoff, whereas levels further upslope responded to rainfall with a delay. To represent these differences in the model, the hillslope was subdivided into a riparian and an upslope reservoir. The performance of the new model was compared to that of simpler model variants without spatial differentiation and with or without the new formulation allowing for interactions between unsaturated and saturated storage. The new model approach provided the best results for simulating both runoff and groundwater dynamics. The subdivision of the hillslope accounted for most of the performance increase. To further test the model structure, 18O-concentrations in the stream were simulated and compared to measured values.

Authors/Creators:Seibert, Jan and Rodhe, Allan and Bishop, Kevin
Title:Simulating interactions between saturated and unsaturated storage in a conceptual runoff model
Series/Journal:Hydrological processes (1099-1085)
Year of publishing :2003
Volume:17
Number:2
Page range:379-390
Publisher:John Wiley & Sons, Ltd
ISSN:1099-1085
Language:English
Additional Information:The original publication is available at John Wiley & Sons, Ltd
Publication Type:Journal article
Refereed:Yes
Full Text Status:Public
Keywords:conceptual modelling, hillslope hydrology, saturated–unsaturated zones interactions, water storage
URN:NBN:urn:nbn:se:slu:epsilon-1-25
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-1-25
ID Code:3215
Department:(NL, NJ) > Dept. of Environmental Assessment
Deposited By: Jan Seibert
Deposited On:25 Apr 2008 00:00
Metadata Last Modified:02 Dec 2014 10:19

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