Development of a simplified unsaturated module for providing recharge estimates to saturated groundwater models
✍ Scribed by C. R. Beverly; R. J. Nathan; K. W. J. Malafant; D. P. Fordham
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 475 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0885-6087
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✦ Synopsis
This paper describes the development of an integrated saturated/unsaturated catchment model of salinity processes and its application to an irrigated and dryland district in northern Victoria, Australia. The model simulates a coupled surface water and groundwater system in which a lumped conceptual model is used to model one-dimensional movement through the unsaturated zone, and a distributed model is used to simulate threedimensional saturated groundwater ¯ow. Movement of water through the unsaturated zone was found to be dominated by macropore ¯ow, and accordingly the classical matrix ¯ow approximations described by the Richards equation were not used. Instead, a conceptual model of the unsaturated zone was developed to simulate soil in®ltration, recharge to the underlying groundwater system, capillary rise and crop evaporation on a daily time-step for each active cell within the model domain. Subsurface lateral ¯ow between each vertical soil column is not permitted, though once in the saturated zone lateral ¯ows are handled by the groundwater model. Salt movement through the pro®le is simulated using a mass balance approach, and separate conceptual formulations are used to generate salt export along the drainage lines.