Lake Pepin has two water quality impairments: turbidity & excess phosphorus.
Turbidity or water “cloudiness” is a problem in upper Lake Pepin where sediment flows into the lake and is easily resuspended by wind and waves. The turbid or “cloudy” water acts like a shield, blocking light penetration and initiating a cascade of impacts, from reduced vegetation to loss of fish and wildlife habitat.
All of Lake Pepin is impaired for excess phosphorus, but lower Lake Pepin is most susceptible to impacts because light penetration is available to support vegetative growth. When conditions are right, excess phosphorus causes algae blooms that reduce light and oxygen necessary for animal and plant survival. It also makes water unsuitable for recreation. The last major algae bloom in Lake Pepin occurred in 2014 during a period of low water flow (Minnesota Department of Natural Resources).
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This blog post was published in the Red Wing Republican Eagle as “Our River, Our Lake”, a weekly column provided by Lake Pepin Legacy Alliance. Publication date: February 2-3.