Abstract
Parameter and state estimation algorithms have been applied to a hydrological model of a catchment area in southern Norway to yield improved control of the household of water resources and better economy and efficiency in the running of the power station, as experience proves since the system was installed on-line in the summer of 1978. A nonlinear conceptual state-space model of a Nordic hydrological system is presented in this paper. The model is transformed analytically to a piecewise linear time-discrete form in order to obtain straightforward updating of the gain matrix in the estimator through solution of the Riccati equation. Estimator gains can then be expressed approximately as a function of the state. Discharge coefficients (time constants) are estimated by the maximum likelihood method. Results are presented which show estimated and observed runoffs, and estimates of the state variables.