According to available data, this process has been recorded in the Strezevo reservoir near Bitola. The water quality of this reservoir is very important because the water is used for drinking and for the food processing industry. It can be observed that over a period of five year's, the Strezevo reservoir became more eutrophic, which means that there is a need for measures to protect the water from increased eutrophication. It regulates issues concerning surface water (watercourses, lakes, accumulations and springs) and underground water within an integrated policy and represents the legislative framework for the future management of water resources.