ABSTRACT
Water resource systems are usually distributed and properly described by partial differential equations with respect to time and space. Comparison between the "classical" and "modern" approaches to dynamic systems modeling may be visualized in vector space mappings. The behavior of water resources systems often changes with time. For example, as the urbanization proceeds, the proportion of the urbanized watershed area, which is impervious, increases, causing the relationship between storm rainfall and runoff changes. Although the nature of water resources systems operate continuously in time, the data are often collected and analyzed using discrete-time intervals, especially when a digital computer is involved in the data storage and analysis. The optimal control problem is to "steer" the system by controlling the inputs which generate the desired outputs while a chosen performance index is optimized. The continuous-time deterministic state variable model is mathematically formulated by means of two equations: the state equation and the output equation.
