50th Street Relief Storm Sewer
The South Basin region of the Village of La Grange was subject to frequent flooding, concentrated at several depressions which are drained by an undersized sewer system without a suitable overland flow path. Notably, this area experienced extensive flooding and property damage resulting from rainfall events during the summers of 2010 and 2014. The severity of flooding raised concerns regarding the condition and capacity of the existing drainage system.
Baxter & Woodman performed analyses of the existing drainage system and several conceptual flood reduction alternatives using XPSWMM. Exhibits and cost estimates were prepared for each alternative, and results, conclusions, and recommendations were summarized in a technical memorandum. Construction of a 4,400 lineal foot relief storm sewer discharging to the Hanson Quarry was found to reduce flooding far more effectively than other alternatives considered. It was recommended as the preferred option, along with lateral extensions to nearby flood-prone areas which could be constructed using a phased approach. A floodwall creating upland stormwater storage west of Brainard Avenue was presented as a secondary recommendation.
The Village retained Baxter & Woodman to complete final engineering for both the relief storm sewer and floodwall alternatives. Construction of the first phase of the relief storm sewer was completed in Spring 2018.