A Tool for Evaluating Risk to Surface Water Quality Status

Water quality Risk Analysis Tool (WaterRAT) is recently developed software for supportingsurface water quality management. The software contains a library of river and lake quality models, aiming togive flexibility over specification of model scope, complexity and scale. Various sources of uncertainty canbe included in the analysis, including uncertainty in boundary conditions, initial conditions, parameters,model structure and management objectives. Water quality can then be modelled allowing for these sources ofuncertainty. Important data uncertainties can be indicated, and so data collection programmes can be suitablyrefined. In this paper, the motivation for the WaterRAT tool and the methods it employs are presented, itsfeatures are described, and its utility for uncertainty evaluation and sensitivity analysis is demonstrated usinga river water quality management problem. Emerging challenges for modellers, which cannot yet beaddressed using WaterRAT, are discussed.