County Highway 19 Stormwater Re-Use Project

HR Green was contracted by Washington County to complete the conceptual, preliminary, and final design of two stormwater re-use designs associated with a proposed two-mile-long County road expansion project. The intent of the project was to provide nutrient and suspended solid load reductions to downstream water bodies.

In addition to addressing transportation-related elements, this project required innovative stormwater management designs to achieve the multi-disciplinary project goals. The specified water resource goals included addressing TMDL nutrient reduction requirements, meeting the City of Woodbury and South Washington Watershed District infiltration and peak flow requirements, while preserving several wetlands adjacent to the road corridor and not acquiring new right-of-way. HR Green found a solution through an innovative stormwater reuse plan, which captures roadway stormwater in two existing ponds and is used as irrigation water for two golf courses adjacent to the roadway corridor. The systems are estimated to reduce potable water usage by over 40 million gallons annually. The re-use pumping networks will be integrated into two existing golf course irrigation systems and provide water for new water amenities within the public golf course.

The stormwater re-use project resolved multiple concerns including:

1. 40 MG/Year of irrigation water for the golf courses being sourced from stormwater in place of the previous source demand from the local aquifer.
2. 100 lbs. /year reduction in phosphorus loading to Colby Lake – exceeding TMDL reduction requirements.
3. Capital Costs for the re-use system were entirely paid for by State Grants and Local Watershed Grants. HR Green was tasked with identifying funding opportunities and submitting funding applications.
4. Limiting wetland impacts and no permanent right of way required.