Major stormwater system overhaul proposed to prevent flooding

In a recent government meeting, officials presented a comprehensive analysis of the storm drainage system in a 170-acre area, revealing significant deficiencies in its capacity to handle stormwater runoff. The existing sewer system, which can manage only 350 cubic feet per second, is vastly inadequate compared to the estimated 900 cubic feet per second generated during a typical 15-year storm event.

To address these issues, the team proposed several critical improvements. Key recommendations include upgrading catch basins to enhance surface runoff management, enlarging underground conveyance piping, and installing approximately 160 new catch basins. Additionally, the plan includes the construction of a 42-inch trunk line and an extended detention system designed to temporarily hold excess water during peak runoff periods.

The proposed enhancements also incorporate green infrastructure practices, such as pervious concrete alleys and bioretention areas, aimed at promoting stormwater infiltration and reducing overall runoff into the existing systems. These measures are intended to mitigate the impact on Rock Creek, ensuring that the outfall remains intact.

Brian Smith, a hydrology and hydraulic analysis expert, highlighted that the updated design reflects a more detailed understanding of the area's needs compared to previous proposals made in the summer of 2022. The current plan includes additional storm drain piping and inlets, particularly on Wordway Street, and introduces trenchless installation methods for some extended detention systems to minimize disruption to surface traffic and utilities.

The meeting underscored the urgency of these improvements, as the existing infrastructure is currently operating at only one-third of its required capacity, posing risks of flooding and environmental impact during heavy rainfall events.