This final thesis elaborates the concept of preliminary design of drainage system of the Mlaka area. The solution is to set up a stormwater dreinage collector following public roads and streets that will drain surface stormwater and evacuate it using the collector network provided by this solution. The entire system connects to the existing main combined sewerage collector and is discharged to the recipient via a spillways or at Delta watewater treatment plant. The introducton part summarizes the conceptual design, general terms and expressions that appear or may occur when talking about stormwater managment, information about the existing condition and characteristics of the area. The main part gives a more detailed elaboration of the process of planning stormwater drainage. It gives an insight into the methods that can be used and applied, as well as a detailed procedure for processing the input data and their use in the selected method. The table calculations for the two return periods and their comparisons are presented. This section also covers the static calculation of the selected sections, an approximate cost of construction, and graphical representations of the situation, longitudinal cross-section and details of the selected elements. The final part gives a conclusion and the mentioned literature that was used in the preparation of this paper.