Chester C. Kisiel

DISTRIBUTION OF DYNAMIC WATER LEVEL IN A SHALLOW LAKE

ABSTRACT The shore of a large and shallow reservoir or lake may incur damages caused by high or low static water level, as well as from dynamic water level rises induced by wind; thus, the random variables representing, respectively, static water level and wind-induced rise must be added. The case study of Lake Balaton, Hungary, illustrates a proposed methodology to estimate, on the one hand, the distribution function of monthly static water level and on the other hand, that of monthly maximum rise caused by wind (seiche plus waves). We consider one section of lake shore which is homogeneous from the viewpoints of types of structure, dominant winds and corresponding values of fetch, so that a well-defined damage function can be used later for that section. A convolution of the two distribution functions is performed to yield the distribution function of monthly maximum water level. On the basis of existing data, normal distributions are suggested for either static or dynamic water levels. Extensions and t...

Control of hydrologic systems for multiple uses in a closed-loop framework

Abstract The role of linear control theory as an aid to the integral control of hydrologic systems is investigated for the case of a combined lake and aquifer storage system that supplies either a deterministic or stochastic water demand. Only lumped time-invariant systems are considered but both deterministic and stochastic inflows to storage are allowed. The computational example allows for recharge of lake water into the aquifer as well as for the subsequent diversion of pumped groundwater back to the lake. Stability criteria are presented for the closed-loop features of the overall control system. Under a quadratic loss criterion, a calculus of variations problem, subject to constraints imposed by the system equations can be solved for the optimal release policy from the lake and aquifer and optimal feedback policy from aquifer to lake.