In this report, it is estimated how a Danish municipality such as Hjørring Kommune is able to optimize the cutting of weeds in public watercourses? This is investigated using data currently available to the Danish municipalities. Data is mainly obtained from Miljøportalen. A conceptual model describing the development of the water level in watercourses is set up. Thus this model depends on individual factors that overall controls the water level – growth of weeds, precipitation and weed cutting. Each of these factors has been analyzed through supporting research questions. The biomass of the weeds can not be measured accurately, and thus this must be estimated by looking at how the growth of weeds affects other parameters such as water level and water discharge. Since only data concerning the water level was found to be actual measured data, it is relevant to investigate how the discharge of water is calculated in the time series on Miljøportalen. It can be concluded that it may well be possible to optimize the cutting of weeds at station Astedbro in Uggerby Å – which is the station data is collected from. Should this further need to work on a larger scale, more data is required.