Until recently, it never occurred to most Minnesotan’s that water could be a finite resource. After a string of dry summers resulted in low water levels for White Bear and other area lakes, however, local communities have begun looking for innovative ways to reduce groundwater pumping. Reusing stormwater runoff for irrigation is a relatively new idea that is gaining popularity because it offers the elusive possibility of addressing two problems with one solution – reducing stormwater pollution and conserving groundwater resources.
In late 2014, the Rice Creek Watershed District completed a massive stormwater reuse project in partnership with the City of Hugo and Oneka Ridge Golf Course that will capture and reuse up to 32 million gallons of nutrient-rich stormwater that would otherwise flow into Bald Eagle Lake, contributing to excess algae growth and poor water quality. The project received additional funding from a $497,100 Clean Water Fund grant from the Minnesota Clean Water, Land, and Legacy Amendment.
The foundation of the Oneka Ridge project is a large stormwater pond near the 18th hole that collects runoff from about 1000 acres of land. The pond connects to an irrigation system that waters 116 acres of turf. Extra water not needed for irrigation is pumped into perforated pipes so that it can soak into the ground and recharge shallow groundwater supplies. According to estimates, the system will reduce the golf course’s groundwater pumping by up to 50%, though the actual amount will vary from year to year depending on how much rain there is. By reusing the water instead of letting it run off, Oneka Ridge will also keep 75 pounds of phosphorus per year out of Bald Eagle Lake.
Golf courses, athletic fields and homeowners associations are ideal locations for stormwater reuse projects because they have ample space for stormwater ponds and are usually using a lot of water to irrigate turf. The South Washington Watershed District recently worked with Prestwick Golf Club in Woodbury on a similar project that uses stormwater runoff from County Road 19 for irrigation. Meanwhile, in Minneapolis, the University of Minnesota has designed a new eco-friendly dormitory that uses stormwater runoff to fill and flush toilets. A similar system at the new Saints Stadium in St. Paul will use stormwater from the nearby Metro Transit facility to irrigate the ball field and fill 10% of the toilets.
Homeowners interested in using stormwater to water lawns and gardens can install underground cisterns to collect runoff from rooftops or driveways. Several years ago, Jackie Metelak, a Master Gardener in Mahtomedi, replaced her driveway with porous pavers and installed an underground cistern to collect water for her many gardens. Trinity Presbyterian, a church in Woodbury, installed a similar cistern on their property, along with raingardens and a porous paver patio. Washington Conservation District provided technical assistance for both projects, while the local watershed districts supplied cost-share funding.