Soil Water Dynamics in the Jarrah Forest of South-west Western Australia

Soil water dynamics were measured on a hillslope transect in the jarrah forest of south-west Western Australia over the period 1984-86. The annual maximum to minimum unsaturated soil water storage was approximately 480 mm. This did not change significantly in years of substantially different winter rainfall. The depth of infiltration was dependent on annual rainfall, with groundwater recharge occurring over the whole hillslope in wet years but confined to the lower slopes in dry years. The average summer drying rate of the soil profile to 6 m depth was 3.5 mn day-1. In late summer the drying rate decreased downslope but increased midslope. Two relationships between streamflow to rainfall ratio and soil water storage were identified, the first from May to September and the second from October to December.