Delivering a high-capacity stormwater solution in Des Moines

Abstract

When a freight facility in Des Moines, Iowa, needed more than 430,000 cubic feet of underground stormwater storage to expand their parking, Prinsco’s HydroStor® HS290 chambers played a key role in the solution. The project included two systems, one for a large pond that was boxed in by existing buildings and another for a ditch adjacent to the parking lot.

The main system used 1,833 HydroStor HS290 chambers to replace the existing pond, providing 379,000 cubic feet of stormwater storage. And to transform the ditch into more parking, 631 HydroStor HS75 chambers were installed, expanding the storage capacity by 54,000 cubic feet.

This project required the team to solve unique challenges like high groundwater, weak soils, and an unmarked water main. To ensure stability in weak soils, the team reinforced the base with layers of rock, geogrid, and more rock. When the unexpected water main was discovered, Prinsco engineers reworked the design and delivered a revised set of plans within 24 hours to keep the project on schedule.

Key project features

• Strict parameters: The project team worked in an area boxed in by buildings and other infrastructure.
• Moving a pond underground: The site was home to a large pond that collected runoff for the surrounding 20 acres. This water continued to flow into the job site during the project, presenting an additional challenge of keeping the site dry.
• Deep covers and weak soil: The base was reinforced with layers of rock, geogrid, and more rock to create a solid base to support the deep cover application.
• 24-hour plan revision: When the team encountered an unmarked water main, Prinsco engineers quickly revised the plans to keep the project on track and on time.

See how the site went from pond to parking lot:

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