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Water Quality

The effort to protect Lac Courte Oreilles is backed by the best science available. COLA has partnered with established, independent experts in the fields of limnology, water conservation, and land and soil impacts. A few examples follow.


Protecting Two-Story Lakes: A Battle Against Phosphorus and Climate Change

Hans Holmberg

Hans Holmberg

Hans Holmberg, a Senior Engineer and Associate Vice President with LimnoTech, gave this presentation at the 2017 Minnesota Water Resources Conference held at the Saint Paul River Centre in Saint Paul, Minnesota, on October 17-18, 2017. This conference is one of the largest conferences of its type in the country - attendance in 2017 was probably in the 7-8 thousand range - and it drew scientists from around the world.  

Hans presented the work undertaken by LimnoTech at COLA's and the LCO Tribe's direction to establish the link between phosphorus concentration and oxythermal habitat for two-story lakes. This is the cutting edge research underpinning the need to list all of LCO as an impaired water and to assist the WDNR's rule-making process establishing a protective site specific phosphorus criterion for LCO ... to say nothing about helping out the cisco and whitefish in the lake.


Total Maximum Daily Load Study, Site Specific Criterion Proposal & More

Click on the photos at the bottom of the page to learn more about:

  • COLA's and the LCO Tribe's Total Maximum Daily Load study and Site Specific Phosphus Criterion proposal, which detail how COLA has worked with the LCO Tribe and LimnoTec, to compile and assess water quality data over many years.

  • How phosphorus pollution coming from Musky Bay is now affecting all of the West Basin of LCO.

  • Why COLA's science led to the listing of Musky Bay as an impaired water in 2014 and the likely listing for the entire lake in 2018.

  • How rare and precious is LCO's two-story cold-water fishery.

  • The historical timeline detailing the challenges facing LCO.

Please take a look at our highest-priority initiatives and accomplishments.

recent threats

Blue-green algae bloom

When a lake looks like pea soup, that’s the effect of a blue-green algae bloom. A first-ever bloom of this kind developed on Stuckey Bay on or about Sunday, November 6, 2016 and lasted for five days.

Fish die-off

In October 2016 there was a massive die-off of whitefish and cisco in LCO. Poor water conditions choked off the rare habitat. See a comprehensive report here.



Issue 2  Saving the lake

Issue 3  COLA takes another giant step in stewardship

Issue 8  'Lac Courte Oreilles - a rare gem'

Issue 13  ‘Death by a thousand cuts,’ Chairman Mic Isham’s focus on water quality, environment'

Issue 31 ‘The Painted turtle: Now we know’