This presentation outlines the situations faced at the design and construction stages of the proposed Lakeshore Substation, as well as the measures taken to mitigate the risks and deliver the project. The site was 14-hectare farmland located in the southern Ontario plain. A portion of the station falls in a regulated drinking water intake area for the county. The approach was to provide a 350 mm layer granular base, and a drainage network of 1,200 runs, totaling 14,000 meters of underdrain pipes to keep the station dry. The purpose of the underdrains are to intercept surface runoffs and store them in the drainage network before releasing to the environment via an undersized solid pipe. Modified Rational Method was used to model the storm events and design drainage piping however, due to the sensitive nature of the location, USEPA SWMM 5.1 had to be introduced to re-model the storm events to ensure compliance of the local Conservation Authority regulations. Comparing the results between the two modeling approaches, it is noticed that certain boundary parameters for SWMM 5.1 need to be carefully chosen in order to achieve reasonable results.