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Reclaiming sandplain seeps by intercepting perched groundwater with eucalypts
Author(s) -
George R. J.
Publication year - 1990
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/ldr.3400020103
Subject(s) - petroleum seep , groundwater recharge , aquifer , hydrology (agriculture) , groundwater , geology , soil salinity , salinity , environmental science , ecology , oceanography , biology , geotechnical engineering , methane
At a sandplain seep at East Belka in the Western Australian Wheatbelt, saline groundwater discharge occurs from a shallow (approx. 2 m) perched aquifer of moderate permeability (0.15 m day −1 ). Groundwater qualities range from over 2,500 mS m −1 in the saline area, to between 660 and 1,700 mS m −1 in the plantation. In 1986 five varieties of eucalypts ( E. globulus, E. cladocalyx var. nana and three provenances of E. camaldulensis ) were planted across the contour upslope from the seep on about 1.0 per cent of the catchment. By 1989 the seedlings had grown to heights of up to 6.5 m. Despite above‐average rainfall over the study period, perched water‐tables under the plantation and seep were progressively lowered (approx. 0.5‐1.0 m) until the area was dry at the start of the 1989‐1990 summer. Wheat ( Triticum aestivum ) established on the seep and adjacent paddock in May 1989, provided a yield of over 1.0 t ha −1 on a site that had been unproductive for 20 years. The method has the potential to reclaim much of the existing eastern and northern wheatbelt where there are salinity problems caused by perched groundwater, and could prevent recharge of the regional aquifer beneath the sandplain seep. However, additional techniques will be required to prevent deep aquifer discharge caused by steadily rising (approx. 0.15 m yr −1 ) regional water‐tables. Discharge and associated dryland salinity from the regional system are expected to be major problems during the next 40 years at the site investigated.