Exact Solution Technique for Water Quality Models

A wide variety of deterministic simulation models have been applied to characterize and predict water quality parameters in rivers and estuaries. General differences in resolution (level of refinement) among models are associated with the degree of time and resolution, with the number and type of water quality parameters included in the model, and with the mathematical solution technique. For any specific model application, there is some optimal combination of these three considerations depending on the purposes to which the study is addressed. When certain systems of steady-state first-order linear differential equations will adequately satisfy the study objectives (which is often the case for rivers), an exact solution techniques can be utilized. To use numerical solutions techniques for the same equations would be expensive, inefficient, and would introduce some numerical distortion into the model responses.