By Todd Hubmer, P.E.
The state of Minnesota is blessed with an abundant amount of water. We are the land of 10,000 lakes, numerous aquifers, and miles upon miles of streams and rivers. We are also home to the largest fresh water lake on the planet—Lake Superior. Over the last couple of decades, the way we think about all of this water has drastically changed.
In decades gone by, we looked at stormwater runoff that comes from the sky and lands on our rooftops, streets, yards, and fields as a waste product that needs to be whisked away to the nearest lake, stream, or wetland as quickly as possible to prevent flooding of our fields, homes, and businesses. Today we must think about stormwater in a new way, as a resource to help preserve limited groundwater supplies.
An integrated approach
We can no longer manage water as separate silos of drinking water, ground water, surface water, and wastewater; rather, we must consider all of the components of water into one approach—an integrated water management approach.
Today’s water quality toolbox has expanded, and municipalities have a variety of tools that can be used to develop an integrated approach to water management. These tools deal both with the removal of pollutants contained in water and the quantity of stormwater we discharge from individual sites.
Keeping stormwater as close to the source as possible is the most advantageous way to maintain quality, reduce flooding, and recharge groundwater aquifers. In the past, because of Minnesota’s abundant water resources, these tools have not been fully implemented. Today, Minnesota is at the forefront of stormwater reuse and water technologies. It is the home of world-renowned companies that are researching micro-membranes that may someday be used in stormwater along with other techniques yet to be used.
A few examples of integrated water management and stormwater reuse can be seen at the recently constructed local stadiums—TCF Bank Stadium, Target Field, and CHS Field. These facilities are using collected stormwater from impervious surfaces and recycling it either to wash the stadiums or internally for flushing toilets. In other areas, we’re collecting stormwater for the purposes of replacing groundwater for irrigating ball fields or agricultural lands and for washing vehicles.
Another recent example of a unique and integrated water management project in Minnesota is located in the City of St. Anthony Village. A research project was developed through a collaboration involving the University of Minnesota, Hennepin County, the cities of Minneapolis and St. Anthony Village, and the Mississippi Watershed Management Organization.
As part of this project, a facility was developed to treat the stormwater runoff from 600 acres of urban developed land before it discharges to the Mississippi River. This unique facility was also established to test emerging stormwater treatment technologies, which will benefit the region far into the future.
More ways to manage water
Other examples of integrated water management tools include iron sand filters and special catch basin structures or underground treatment chambers. Iron sand filters can capture dissolved phosphorus and sediment from stormwater runoff.
Catch basin structures and underground treatment chambers can remove oils, trash, and sediment from stormwater before it’s discharged downstream. Stormwater can be harvested and held in underground chambers or surface reservoirs, allowing the water enough time to infiltrate back into the ground and into our aquifers.
We can use stormwater to create streams or creeks that meander through our parks and provide aesthetic and wildlife habitat value. These amenities can help maintain the vegetation in our local parks.
As municipalities in Minnesota embrace the concept of integrated water management, water resource professionals will rise to the occasion. The number of tools in our water quality toolbox will multiply as new technologies are discovered and deployed throughout Minnesota cities, ensuring a legacy of water quality is preserved for future generations to enjoy.
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