Keeping our waterways clean
Sediment and microbial loads are two key indicators of water quality. Modelling these contaminants can be done with another powerful tool, SPARROW.
“SPARROW simulates the generation of sediment loads in river subcatchments, and then follows these contaminants downstream,” explains NIWA’s Dr Sandy Elliott. “It factors in losses en route, to give a prediction of mean annual sediment loads for each stretch of river. Similarly, research into the persistence of different microbes in streams which pose a risk to human health, such as E.coli, Campylobacter, and Clostridium, means we can model survival of these organisms and their movement from sources down the drainage network.”
“We have used extensive knowledge of catchment geology, rainfall, and land use in catchments to create our sediment models, and information on farm animal stocking rates and behaviour on pastoral land to model microbial contaminants.”
SPARROW forms the backbone of a further integrated modelling system, CLUES, which is being developed to predictthe outcomes of large-scale land-use change on a range of biological, physical, and socio-economic factors (see Water Resources Update 22, May 2007).