Lake Pepin Watershed TMDL
Eutrophication and Turbidity Impairments: Project Overview
Lake Pepin has been placed on the 2004 list of impaired waters for two types of water quality problems. As a lake, it is impaired by excess nutrients that cause algae blooms, particularly severe during lower-flow periods. As part of the Mississippi River reach extending from the St. Croix River to the Chippewa River, Lake Pepin is also turbidity impaired.
TMDL Background
In accordance with the Clean Water Act, states are required to submit a list of impaired waters to the U .S. Environmental Protection Agency every two years. Minnesota’s 2006 303 (d) List of Impaired Waters includes 1,008 lakes and 296 rivers, some of which are listed for multiple contaminants. Approximately 10 percent of the streams and 16 percent of the lakes in Minnesota have been assessed for impairments.
In addition to submitting the list, states must evaluate impaired waters to determine progress toward cleaning up or restoring listed waters. A Total Maximum Daily Load (TMDL) study must be conducted for each pollutant affecting an impaired water. The study identifies all pollutant sources and determines the amount of reduction needed by each source to effectively restore water quality. State agencies, local organizations and other stakeholders work together using water sampling data, computer modeling and public input to develop TMDLs.
Description of Water Body
Lake Pepin is a natural lake on the Mississippi River. It has a surface area of about 40 square miles and a mean depth of 18 feet. Its watershed is about 48,634 square miles (approximately half of Minnesota’s total land area plus a portion of Wisconsin) including the Upper Mississippi, St. Croix and Minnesota Rivers.
Source: Minnesota Pollution Control Agency - www.pca.state.mn.us
Eutrophication and Turbidity Impairments: Project Overview
Lake Pepin has been placed on the 2004 list of impaired waters for two types of water quality problems. As a lake, it is impaired by excess nutrients that cause algae blooms, particularly severe during lower-flow periods. As part of the Mississippi River reach extending from the St. Croix River to the Chippewa River, Lake Pepin is also turbidity impaired.
TMDL Background
In accordance with the Clean Water Act, states are required to submit a list of impaired waters to the U .S. Environmental Protection Agency every two years. Minnesota’s 2006 303 (d) List of Impaired Waters includes 1,008 lakes and 296 rivers, some of which are listed for multiple contaminants. Approximately 10 percent of the streams and 16 percent of the lakes in Minnesota have been assessed for impairments.
In addition to submitting the list, states must evaluate impaired waters to determine progress toward cleaning up or restoring listed waters. A Total Maximum Daily Load (TMDL) study must be conducted for each pollutant affecting an impaired water. The study identifies all pollutant sources and determines the amount of reduction needed by each source to effectively restore water quality. State agencies, local organizations and other stakeholders work together using water sampling data, computer modeling and public input to develop TMDLs.
Description of Water Body
Lake Pepin is a natural lake on the Mississippi River. It has a surface area of about 40 square miles and a mean depth of 18 feet. Its watershed is about 48,634 square miles (approximately half of Minnesota’s total land area plus a portion of Wisconsin) including the Upper Mississippi, St. Croix and Minnesota Rivers.
Source: Minnesota Pollution Control Agency - www.pca.state.mn.us
Eutrophication
Aging process of lakes (natural or cultural); high level of nutrients causing excess algae production.
Aging process of lakes (natural or cultural); high level of nutrients causing excess algae production.
Turbidity
Measures water clarity; related to particles in water (sediment and algae)
Measures water clarity; related to particles in water (sediment and algae)
TMDL
The total amount of a pollutant that a water body can carry without violating water quality standards.
The total amount of a pollutant that a water body can carry without violating water quality standards.
