ABSTRACT
Practically all models that are described as ‘‘distributed,’’ have lumped characteristics (input parameters, spatial and boundary conditions, etc.). Rainfall and runoff processes may be distributed, but are likely not ‘‘fully distributed.’’ For example, the ANSWERS2000 model[3] is considered a distributed-parameter hydrologic and water quality model for watershed scale runoff and water quality evaluations. It breaks the watershed into ‘‘elements’’ that contain lumped parameters based on dominant characteristics. The size of the elements can be selected based on variability conditions and overall size of the watershed. Water is passed from one element to another in a distributed network.
