This project will be located at Nimar in Riyadh Saudi Arabia. Korean Saudi Ltd Co. has been awarded the main contract on this development. The city of Riyadh is increasingly experiencing strong flooding events which have caused substantial property damage and some fatalities in the recent past. The last strong rainfall event occurred. Stormwater networks. In this region the high subsurface water level causes many problems for civil structures (roads and buildings). The aim of the study was to analyse the existing situation in order to find present and future orientated strategies to solve these problems. After analysing the existing situation, recommendations in the fields of stormwater drainage, stormwater treatment, disposal points and lowering the subsurface water level were given. The required steps to find cost optimized solu-tions were developed and defined. To prevent the construction of drainage pipes covering the long distance from the western region to the coast, a new drainage system was proposed including: artificial evaporation lakes in some districts in the western part of the project area. The objective of the project is to stablish a comprehensive stormwater drainage plan for the whole city of Riyadh, including the design of all its components(networks, channels, pipes). Additionally, a threee dimensional (3D) mathematical model to simulate the sormwater flow in teh greater Riyadh city and to control the urban drainage flow is required. The preparation of the comprehensive plan is achieved through several phases. The demanding process to develop an efficient stormwater drainage system in an urban area with predominantly low gradient of terrain is one of the major challenges in this project. The project involves Construction of a storm water drainage network. The project is currently under construction and is expected to be completed by Q3 of 2019.