Hillcrest Knoll Park

Prinsco Develops Award-Winning Customized Retention System for Hillcrest Knoll Park

Quick Details

Product Type(s):

Application Type(s):
Underground Retention/Detention

City of St. Paul, Minnesota

Eureka Construction, Inc.

WSB & Associates, Inc.

Installation Date:

St. Paul, Minnesota USA


Hillcrest Knoll Park is part of the Hillcrest neighborhood in east St. Paul, Minnesota. This area of the city was a swamp in the early 1900s, but was developed in the 1950s during the post-World War II housing boom. After troubleshooting ongoing flooding problems, including the flash floods of 1997, St. Paul created the park as a public green space.

In 2012, the City of St. Paul determined that additional water management was needed to mitigate flooding issues with the park and bordering homes. They brought in WSB & Associates to determine the best solution to fit their unique situation. Considering the flooding history of the region and the large geographic area involved, a very substantial BMP drainage retention system was needed.

Originally, the proposed retention system filled the entire footprint of Hillcrest Knoll Park. WSB & Associates called Prinsco’s expertise to help develop a practical and creative solution using HDPE pipe. Prinsco’s engineering department worked very closely with WSB to develop a system design of maximum efficiency using corrugated HDPE pipe. The use of HDPE allowed for the system to be tailored specifically to the project while meeting the high volume storage requirements, saving material and labor costs and providing a solution with maximum service life. We also addressed their unique maintenance concerns by providing a custom designed clean-out system.

Our cost effective, highly customized final project solution enabled the storage of 85,220 cubic feet of water while maintaining the outstanding service life that corrugated polyethylene provides.


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Project Brief

With any system of this size, the investment of time and financial resources is very substantial. Prinsco was able to contribute to the overall efficient use of resources in a number of critical ways.

First, our engineering department was instrumental in helping to reduce the footprint of the retention system being proposed. Prinsco’s engineering team reviewed the plans and, in collaboration with the WSB team, found that the overall project footprint could be reduced by upsizing pipe in certain areas and eliminating pipe in other areas. The final system was designed entirely out of 60 GOLDFLO WT, eliminating the need to excavate and additional 3,500 square feet of land space and install several hundred feet of 48pipe. Prinsco worked through these design changes with the WSB team over a period of two months, arriving at a final solution which not only reduced the product needs, but decreased the excavation footprint, the amount of imported backfill needed and the overall installation time.

Second, the City of St. Paul had some unique system management concerns. Prinsco worked closely with the entire team to create a custom-designed clean-out solution that allowed for convenient and ongoing maintenance.

Third, this large scale Prinsco retention project was installed by the contractor in just three days despite their relative inexperience with systems of this type. The efficient installation timeline was attributed to the ease of product handling, convenience of our GOLDFLO WT bell/spigot joint system and ongoing sales/engineering support.

HDPE pipe was the ideal product solution for this retention system because it offers an unmatched service life. In addition, plastic pipe system configuration is highly flexible, allowing for unique, custom-designed solutions that can maximize the efficiency of each project saving valuable time and money.