The influence of climate as expressed by the Thornthwaite Index on the design depth of moisture change of clay soils in the Hunter Valley

This paper presents details of the method used to determine the Thornwaite Index which is a measure of aridity. The index is then used to provide improved estimates of the depth of design moisture needed for estimating reactive clay movement in the Hunter Valley. Importantly, the method described is consistent wit the methodology and philosophy of AS 2870.