Hydrologic systems are generally complex and physical laws to describe explicitly natural hydrologic phenomena are difficult to formulate. Thus recourse to hydrologic models must be made, whereby hydrologic systems are represented by a set of simplified mathematical equations.
Hydrologic systems are often treated (depending on availability and quality of data and the objectives of a given study) in various degrees of complexity from deterministic to purely stochastic. The deterministic approach assumes a priori knowledge of the physical mechanisms operative in the system, while stochastic techniques assume that the system behavior can be described by probabilistic laws.
Deterministic hydrologic models may be further sub-classified as lumped, semi-distributed to fully distributed models. Distributed hydrologic models are those that undertake the task of accounting for spatial variations of hydrologic processes. It should be noted that, a truly distributed model is possible only if the process can be described by an equation having an analytical solution. A lumped model on the other hand ignores spatial variations in hydrologic processes may be easier to deal with. However, with the development of advanced computer technology it is increasingly becoming easier to model complex water resources systems.
No comments:
Post a Comment