The development of a new RTC system for a polder landscapes whose geography and current management practices developed over a time span of hundreds of years is a complex undertaking. The results to be achieved are generally formulated in terms of policies instead of clear requirements. Both in the literature on controller design and in practice the full process needed to transform policy statements into a control system that best serves those policies is somewhat neglected. Part of the problem is the rapid development of technology in general and resulting new options for automatic control. This is especially problematical in an environment where this path should be traversed together with the stakeholders. An analysis is presented of present Dutch practice and a proposal is made for a new approach that may well be applicable to RTC development for other complex water systems.

A polder-boezem system consists of a (large) number of polders that pump their drainage water into a network of watercourses and lakes. A few large pump stations then pump the drainage water into rivers or the sea. In some cases a sluice gate is used when water levels allow it. A receding horizon control algorithm for a polder-boezem system is presented where the selection of the control action is based on a prescribed order of use for the different states of available pumps and sluices. It is an extension of an earlier algorithm that operated boezem pump stations only. A further extension is proposed that will allow inclusion of the control of polder pumps. Arguments are presented to support the claim that, from the point of view of transparency, this algorithm is better suited to the control of polder-boezem systems than receding horizon control with a traditional objective function.