St. Croix Secrets


When looking at the St. Croix River, do you ever wonder where all that water came from?  The river is primarily fed by the rain and snow that falls on its watershed and flows overland to small streams that eventually find the St. Croix.  The river also receives smaller contributions of water from groundwater discharge, which is water from underground aquifers or rainfall that soaked into the soil and stayed close to the surface. The total amount of water you see at one time in the St. Croix River is a combination of surface runoff and groundwater discharge from the upstream watershed.

When you see water go down the drain in your bath tub, do you ever wonder where it goes?  The wastewater typically goes through a Subsurface Sewage Treatment System, commonly known as septic system, or through a municipal sanitary sewer pipe on its way to a wastewater treatment plant.  Generally in cities, all of the wastewater from our toilets, sinks, showers, and washing machines travels via a municipal sanitary sewer pipe to be treated at a wastewater treatment plant before being released into the local water body.  There is a wastewater treatment plant in Oak Park Heights along the St. Croix River that treats an average of 3.5 million gallons of wastewater per day.  Conserving water at your home or business will help the wastewater treatment plant be more effective and return cleaner water to the river.

When you look at a storm sewer drain in the street, do you ever wonder where that water goes?   Storm drains run directly to the nearest body of water and are not connected to a wastewater treatment plant.  The path of the runoff is often completely hidden from public view.  The stormwater runoff flows through a series of interconnected pipes and outlets into a waterbody, bringing with it a smorgasbord of pollutants that are hazardous to our health and safety.  In some cases the water is directed to a stormwater pond for additional cleansing, which is good, but stormwater ponds only remove a portion of the chemicals present in stormwater runoff before entering the river.  Stormwater runoff is the number one source of pollution to our lakes, streams and rivers.

Since discovery of this problem, we have learned new ways to address it.  There are several strategies or best management practices (BMP’s) for landscaping and land management that can contribute to helping keep our water clean.  Three common and effective BMP options are building raingardens, replacing turf with native plantings, and creating a native plant buffer along your shoreline.  Raingardens are shallow, planted depressions designed to collect rainwater runoff from impervious surfaces and allow the water to soak into the ground within 24-48 hours.  Replacing turf with native plantings will reduce your weekly yard maintenance and will reduce runoff from your property. Shoreline and stream buffers ranging, at least 10 feet wide, help capture runoff and filter pollutants before entering the lake, stream, or river.  Planting native buffers along your shore also provides habitat diversity and prevents erosion of your shoreline.  With slight changes to how we manage our land and the water that falls on it we can greatly improve the quality of our lakes, streams, and rivers.

How do I learn more about improving the water quality in my local lakes and rivers?  Here are a few simple things you can do at home to help clean and conserve water:

  • Collect rainwater in a rainbarrel for watering gardens and landscaping
  • Throw old medicine in the garbage rather than flushing down the toilet
  • Set irrigation timers to water in the early morning, not during the heat of the day, along with adjusting sprinklers to not water the driveway or street

Also there are 3 free workshops offered this spring to teach you about raingardens, native plantings, and shoreline stabilization.

         Blue Thumb – Planting for Clean Water Workshops

  • Tuesday February 28th 6-8pm, All Saints Lutheran Church (8100 Belden Blvd Cottage Grove, MN 55016)
  • Tuesday March 13th 6-8pm, Gander Mountain (14640 W. Freeway Drive Forest Lake, MN 55025).
  • Thursday April 12th 7-8:30pm, Afton City Hall (3033 St. Croix Trail, Afton, MN)

All workshops require R.S.V.P. email: or phone:651-275-1136 ext. 24.  Registration deadline is a day before the workshop begins. To learn more go to or

Guest Writer: Tara Kline is a Natural Resource BMP Technician for the Washington Conservation District. Contact her at 651-275-1136 x.28 or