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Dec 19

Mankato Drinking Water

Posted on December 19, 2017 at 8:39 AM by Michael Stalberger


Drainage update 12/18/2017

Holidays Notice: Due to the Christmas and New Year's Holidays - the DrainageBlog is taking the next two weeks off.  Enjoy your holidays with family and friends and we in the Drainage Office look forward to starting another year of drainage update blogs January 8, 2018.
seasons greetings


Upcoming Drainage Hearings or Meetings:

·         No upcoming meetings scheduled at this time.


Project Updates:

  jd34 impr

  • JD34 (LeRay Twp.)  Crews were still working on installing new tile as of last Thursday, 12-14-17.  Not sure how long crews will continue with a change in the weather coming this week which includes measurable snow and very cold temps.  To my knowledge almost all, if not all, new pipe has been installed on the westerly side of County Road 27.  A small portion of new pipe was also started on the easterly side of the road.  At this time, this is the only project that is still going. 


Drainage Minutes:

Most of our projects are coming to a quick halt this week, with the pending change in weather.  As of last week, we just had the one project still going.  We are still making ditch cleaningrepairs and doing ditch cleanings at this point, but the ice in the open ditches is getting thicker by the day. That makes the cleaning projects all the more difficult to the point that we may have to stop ditch cleaning for the year.

We’ve had a busy last couple of weeks with landowner meetings and hearings.  There is a potential for more improvement projects based on these recent landowner meetings.  Next year will be another fairly busy year with two improvement projects scheduled so far.      One project will start early spring in the Eagle Lake and Madison Lake area.

I’m still trying to get televising completed on the few last systems for the year.  Our televising machine broke down a couple weeks ago.  Hopefully this week we can get back at it and complete some of the televising before the weather makes it unfit to continue.  Televising is always a great and relatively inexpensive way to get a glimpse into the existing condition of a tile system.


Drinking Water Battle:

Each day is a battle in the fight to supply 12 million gallons of clean drinkable water to Mankato residents.  In this battle for clean drinking water, Mankato is a leader in their use of technology to bring quality water that even exceeds federal standards.

The Mankato water plant uses a system from start to finish to make sure our drinking waters are safe.  The more important, and one of the final steps, in making safe drinking water is the use of ultrafiltration membranes.  These membranes are a system of 11,000 plastic tubes roughly the size of a cocktail straw, that are inside of an 8-inch pipe.  These tiny plastic tubes can trap out bacteria and some larger viruses down to about two-hundredths of a micron.  These filtration tubes may be small in size but are very long; if they were all strung together they would stretch 6,000 miles approximately. 

After almost ten years of use and repeated chemical cleansing treatments, these filtration tubes are getting worn out.  A ten-year life is about all that is expected from these filtration membranes.  Mankato water plant crews are now going through the task of changing the membranes out in a two-year project.  This project comes with a price of around $600,000 to change out all of the membranes. 
These filtration membranes do a great job of cleaning sediments and bacterial items, but nothing for nitrates or phosphates. Nitrates and phosphates are an increasingly large issue in many of the wells and drinking water supplies for many Minnesota communities.  These issues of nitrates and phosphates have to be handled separately in a different treatment process. 

One of the ways the City of Mankato is preparing for this possible issue in the future is to do a cost study on a reverse osmosis system which would keep nitrates and phosphates out of our drinking water.  These osmosis systems come at a heavy price tag, as the city of St. Peter just recently made the upgrade to their system.  For the time being, our drinking water is mostly sourced from wells 60 plus feet below our local rivers.  Our wells are at the moment still free from nitrates, but that can change in a hurry and a plan for the future sounds like it’s already in the works.  Mankato has and will continue to provide good, safe, quality drinking water to it’s residents for decades to come.

To read this full article for yourself click the link.


Recent Drainage Inspections – week of December 11 – December 15:


  • JD17 (Garden City Twp.)  We held a landowner meeting to discuss possible future repairs or improvements to this aging system.  The tough thing is the amount of tile in such a small area making for a very costly per acre project. 
  • CD56 (Garden City Twp) I received a report of a large sink hole area along a portion of county tile that dumps into our newly cleaned out open ditch.
  • JD45 (Mapleton Twp.)  We were unable to continue televising because of technical difficulties with the televising unit.  We should be back in business and hopefully finish this week, weather permitting.
  • JD23 (Sterling Twp.)  Inspection of sink hole / tile separation area on this all-tile system down by Amboy.  Picture shows sink hole damage.jd23


  • CD86 (Decoria Twp.)  More ongoing issues with beavers making dams.  We barely had the one beaver dam removed and the beavers built two new ones within a few days.  The two new ones are inside of cross culverts making the removal very tricky.  See cover photo of one of the beaver dams inside the culvert.

Please call with issues you observe on our public drainage system, as there is a lot of open ditch and tile in our county and only two of us in the drainage department.  We will do our absolute best to service your issues and concerns as we receive them.


We require that all repairs to a county drainage system (tile or open ditch) be authorized by one us in the drainage office, either Craig or myself, before any repairs are made.




Ryan Hiniker

Drainage Management Specialist