Salinity Assessment with HARSD: Little River Catchment, NSW

Abstract

The HARSD method (Hydrogeomorphic Analysis of Regional Spatial Data) was applied for salinity assessment of the 1,075 km2 Little River Catchment, Macquarie Valley, NSW. Automated terrain classification was performed using a 25 m resolution Digital Elevation Model (DEM) and potential groundwater discharge sites were identified from a regional-scale hydraulic head surface (HHS) constructed from sparselydistributed borehole data using GIS and hydrologic techniques. These sites compared favourably with mapped salinity in the southern area, but less so elsewhere. Transmissivity, spatially distributed recharge and the HHS formed input to Flownet Analysis Software (FAS), a steady-state groundwater model associated with HARSD, to provide preliminary groundwater and, by inference, salt flux estimates for the 735 km2 Buckinbah Creek subcatchment. Phase-II work will investigate salinity in a high-risk subcatchment of Buckinbah Creek, using hydrological, hydroecological and remote sensing techniques.