SMAC: spatial optimisation model for analysing catchment management

Abstract

The ways in which people use land tends to follow economic motivations. Environmental considerations are often ignored until resource degradation reaches the stage of economic significance. Environmental side-effects of land-use activities are not confined to the area where they apply. In the case of agricultural land use, the way in which farmers use their land may impact on the profitability of neighbouring properties, other properties in the region, and the welfare of the wider community. The question arises as to which land-use practices would be financially viable for the farms as well as ensure environmental sustainability of agricultural land use. This paper outlines the framework of SMAC, a modelling tool that is being developed to analyse the economic and environmental sustainability of land use in catchments. It uses a spatial optimisation approach in a dynamic context. The methodology is applied to the Liverpool Plains catchment in northern New South Wales, Australia. Here, rising saline groundwater tables cause extensive soil salinisation. The underlying hydrological imbalance has been triggered by European-style land-use practices. The conceptual approach of the model combines farm behaviour and catchment response as two process levels. It seeks to provide assistance in developing a land-use strategy for sustainable agriculture in the catchment and provides a tool for assessing the implications of policy changes to enhance the process.