TREE REMOVALS AND SALINE SEEPAGE IN VICTORIAN CATCHMENTS: SOME HYDROLOGIC AND ECONOMIC RESULTS

Average salt concentrations in a number of Victorian streams are related statistically to the proportions of their catchments cleared of trees for agriculture and to other catchment variables. A causal relationship is assumed, so that an economic evaluation of one of the external benefits of tree retention in a given catchment can be estimated. This is done by using the model to predict stream salinity increases that would occur with further clearing, and estimating the costs of such increases by either the costs experienced by water users, or the costs of restoring stream salinity to the original level. The methods are illustrated by application to a representative catchment.