MANAGEMENT OF SANDPLAIN SEEPS IN THE WHEAT-BELT OF WESTERN-AUSTRALIA

Soil salinity in the wheatbelt of Western Australia is caused by discharge of groundwater both from regional groundwater systems and from perched, perennial aquifers. Perched groundwater systems have been studied in five catchments to determine the process responsible for the development of sandplain seeps and methods available for their reclamation. Groundwater interception using drains has been successful in reclaiming saline soils associated with sandplain seeps within 1-2 years. Stock quality water resources are available from these drainage systems. Storage in reservoirs is not recommended where the drainage water exceeds 400 mS/m. Where interceptor drainage is too saline for reservoirs, deeply buried tube drains provide a viable alternative to generate a stock water supply. Plantations of eucalypts are capable of intercepting groundwater and reclaiming sandplain seeps within five years. Evidence from one site suggests that 300 eucalypts were sufficient to intercept and transpire approximately 1000 m3 of brackish to saline groundwater. Tree variety trials have been established and preliminary recommendations are available on suitable species.