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Development of a simplified unsaturated module for providing recharge estimates to saturated groundwater models
Author(s) -
Beverly C. R.,
Nathan R. J.,
Malafant K. W. J.,
Fordham D. P.
Publication year - 1999
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/(sici)1099-1085(19990415)13:5<653::aid-hyp771>3.0.co;2-3
Subject(s) - groundwater recharge , vadose zone , richards equation , infiltration (hvac) , groundwater model , groundwater , hydrology (agriculture) , macropore , geology , groundwater flow , water balance , water table , aquifer , environmental science , soil water , soil science , geotechnical engineering , geography , chemistry , mesoporous material , biochemistry , meteorology , catalysis
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 three‐dimensional saturated groundwater flow. Movement of water through the unsaturated zone was found to be dominated by macropore flow, and accordingly the classical matrix flow approximations described by the Richards equation were not used. Instead, a conceptual model of the unsaturated zone was developed to simulate soil infiltration, 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 flow between each vertical soil column is not permitted, though once in the saturated zone lateral flows are handled by the groundwater model. Salt movement through the profile is simulated using a mass balance approach, and separate conceptual formulations are used to generate salt export along the drainage lines. Copyright © 1999 John Wiley & Sons, Ltd.