CATEGORY: Waste and Storm Water

ENTERING FIRM: TERRA Engineering, Ltd.

OTHER CONSULTANTS: Chicago Testing Lab

OWNER: Village of Kenilworth

DESCRIPTION: After a flooding event in 2008, the Village of Kenilworth Board of Trustees embarked on a mission to identify and mitigate the causes of sewer surcharging and flooding. The eastern portion of the Village has a combined sewer system designed in the early 1920’s that was not designed for the needs of the 21st Century. The problem was further impacted by surcharging of the regional sewer main on Sheridan Road. While the system was able to handle the daily needs for sewage conveyance, the combined (sewage + stormwater) system was not capable of meeting the demands during a larger rain event. When the combined sewer cannot accept all of the incoming stormwater, the sewage-laden water backs up (surcharges) into residents’ basements, the roadway, and even Lake Michigan. Designing and building anew storm sewer was the best answer to providing a long-term solution to the problem. The Village’s goal was to build that system in a way to both address flooding and be environmentally responsible. The Green Streets Infrastructure Program (Green Streets) was specifically designed to tackle the persistent local flooding and basement back-ups issues in the eastern part of the Village. This Phase II project area targeted relief for Raleigh, Leicester, and Warwick Roads. Based upon the evaluation of the Phase I project area, some improvements were planned for Phase II. First, with their established history in roadway applications and selected due to their longer life span and easier removal and reuse, porous pavers replaced the porous asphalt. The design of the Green Streets, Phase II combined porous pavers with approximately 24 inches of an under-road stormwater detention area. Combining these green infrastructure approaches provides an anticipated 282,389 gallons of stormwater detention during major rain events, achieving the goal to eliminate sanitary sewer backups and offer passable roadways during large rain events. The new system was designed in 2020 through 2021 with construction of the project commencing in early 2022. All three roadways planned for improvements were constructed in 2022.Through innovative approach and meticulous planning, TERRA provided hydrology and hydraulic (H&H) modeling of the entire East Kenilworth Watershed, including the existing combined sewer system, proposed storm sewer system, green infrastructure, and overland flow. The thorough evaluation empowered the Village to make well-informed decisions and select the most suitable approach to protect their residents and property from flooding.