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Salinization risk in semi‐arid floodplain wetlands subjected to engineered wetting and drying cycles
Author(s) -
Crosbie Russell S.,
McEwan Kerryn L.,
Jolly Ian D.,
Holland Kate L.,
Lamontagne Sebastien,
Moe Kamilla Grotthing,
Simmons Craig T.
Publication year - 2009
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/hyp.7445
Subject(s) - wetland , groundwater recharge , groundwater , hydrology (agriculture) , environmental science , surface water , arid , subsurface flow , floodplain , soil salinity , aquifer , geology , soil water , ecology , environmental engineering , soil science , paleontology , geotechnical engineering , biology
This study investigated the surface water–groundwater interactions of three semi‐arid floodplain wetlands of the lower River Murray (SE Australia) using a combination of hydrometric, natural tracer and geophysical methods. The current management objective for these wetlands is to mimic the natural surface water flow regime by engineering wetting and drying cycles for the benefit of the biota. However, the impact this will have on groundwater processes and wetland salinization is unknown. This study found that when inundated, two of the wetlands were groundwater recharge features, whereas the other was a groundwater throughflow system. After these wetlands were dried, there was a reversal of the hydraulic gradients and all three wetlands became groundwater discharge features. The transformation of these wetlands to groundwater discharge features after the removal of surface water means that there is an increased risk of salinization when wetting and drying cycles are reintroduced. In arid/semi‐arid regions of the world where wetlands are in direct contact with saline groundwater, extreme caution should be applied when altering the management of the surface hydrology of the wetlands because increases in salinity can impact upon biodiversity. Copyright © 2009 John Wiley & Sons, Ltd.