The river water pumping station at SSAB in Borlänge is a critical part of the factory since it supplies the whole factory with cooling water. The problem with the river water pumping station is that the pressure in the pipes is very dependent on the large water consumers in the factory. The large consumers causes large variations in pressure and water level when they suddenly turns on and off. The second problem in the river water pumping station is that it can not pump enough water to the consumers during the warmer periods of the year. The aim of this thesis is to improve the control system in the river water pumping station by first creating a model of the system which then can be used to test a new controller. The model is verified against measurements from the real process. The results show that the developed model captures the general behavior of the system. Further analysis of the system show that a smaller pump could be the cause of the problem in the control system. In the development of the new controller the smaller pump was then removed and replaced with a larger pump. The new and old controller perform similarly when it comes to pressure and flow rate however the new controller is slightly better when taking the control signal into account because it does not make any large sudden changes.