Ladue Stormwater Project Implementation

The City of Ladue’s Storm Water Management Program (SMP) is a comprehensive, three-phased initiative to alleviate various stormwater concerns in the community. The three phases of the SMP are: Phase I: Needs Assessment / Phase II: Master Plan / Phase III: Projects. The goal of the “Needs Assessment” was to identify stormwater-related problems city-wide including the “health” of the natural streams. The deliverable from this phase was a comprehensive listing and mapping of the identified stormwater-related problems from all sources.

Subsequent to the completion of the Needs Assessment, HR Green completed a stormwater master plan for the project which identified approximately 54 projects throughout the City to address stormwater needs of reduced flooding and improved infrastructure conditions. HR Green was also hired for the design of the two largest projects selected for the Ladue Stormwater Project Implementation.

The Deerfield and Wakefield subdivisions are located in southeast Ladue. Little or no storm sewer infrastructure was constructed at the time of initial development, relying completely on sinkholes to drain the downstream end of the project area. Consequently, a number of highly valuable properties are prone to flooding and have experienced significant damage in recent years. The project is estimated to cost $10 million and is currently undergoing preliminary design with construction anticipated to begin in 2022.

The Willow Hill and Loren Woods subdivisions are located in northeast Ladue. Most of the homes in these neighborhoods were constructed between 1930 and 1960. Little or no storm sewer infrastructure was constructed at the time of initial development. A limited storm sewer system was retrofitted into selected areas at a later date, but it does not meet today’s design standards. The project cost over $2 million with construction completed in Spring 2022.

HR Green completed hydrologic and hydraulic modeling (XPSWMM) and an alternatives analysis for both Ladue Stormwater Project Implementation areas. As part of the alternatives analysis process, HR Green staff met individually with property owners most likely to be impacted by the project and incorporated their input into the various alternatives.