External costs of sand mining in rivers: evidence from South Africa.

Abstract

The valuation of estuarine goods and services serves to highlight the degree to which estuaries contribute to human well-being and to show that the social cost of activities which contribute to estuary degradation could be greater than the private gains. Researchers applied this notion to a list of estuaries in the eThekwini municipal area of South Africa to estimate private gains and social costs of sand mining enterprises. Sand mining in rivers is an important source of raw material for the construction industry, but impacts on sediment yield in estuaries, and therefore on estuarine functioning and service provision. Researchers confirmed the presence of negative externalities in the sand mining industry that are not reflected in the market price of sand, implying that the sand resource is currently being over-exploited, to the detriment of estuarine ecological functioning and long term social well-being. These external costs are estimated at the estuary level for the study area. An assessment of the viability of alternative sand supply sources to serve the growing demand in the construction industry is consequently recommended.