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News Release

August 14, 2014


Contact: Georgia Parham 812-334-4261 x 1203


U.S. Fish and Wildlife Service Issues Assistance Letter to Northern Indiana Public Service Company for Endangered Tippecanoe River Mussels

PDF Version


The U.S. Fish and Wildlife Service today issued a technical assistance letter to Northern Indiana Public Service Company that addresses water flow and imperiled mussels in the Tippecanoe River downstream of NIPSCO’s Norway and Oakdale dams.  The letter outlines ways NIPSCO can avoid violation of the federal Endangered Species Act during dry periods when water flow in the river declines and protected mussels may be exposed and die. 


The technical assistance letter describes the Abnormal Low Flow or ALF Plan that, if implemented, will ensure NIPSCO is in compliance with the Endangered Species Act. The measures in the technical assistance letter, developed jointly by NIPSCO and the Service, go into effect immediately.


“The U.S. Fish and Wildlife Service is committed to its mission to conserve endangered mussels while helping companies such as NIPSCO meet its obligations to the people who share the resources of the Tippecanoe River,” said Scott Pruitt, field supervisor at the Service’s Bloomington, Indiana, office.  “Mussels depend on the same waterways that people value. Maintaining a healthy environment for mussels helps ensure these areas are available to people as well.”


The Service develops technical assistance letters for entities that are in danger of “taking” listed species in violation of the Endangered Species.  “Take” means to kill, harass or harm.  Take can occur during otherwise lawful actions, such as operation of a hydroelectric dam.  Operation of NIPSCO’s hydroelectric facility has resulted in mussel mortality in the river in past years. 


The Service and NIPSCO developed the ALF Plan in coordination with the Indiana Department of Natural Resources, Division of Fish and Wildlife.  Key components of the plan include:

  • procedures for monitoring water flow and taking action when conditions prevail that could result in take of federally listed mussels;
  • a more equitable distribution of water for users and natural resources along the Tippecanoe from Lake Shafer to the river’s confluence with the Wabash River;
  • an estimation of natural run-of-the-river based on flows upstream of the two reservoirs to calculate appropriate flows downstream of Oakdale Dam, as opposed to a set level regardless of natural water level.  This would eliminate NIPSCO’s liability for violating the Endangered Species Act when water is naturally limited;
  • a reduction in the rapid and drastic spikes in flow downstream of Oakdale Dam that disrupt mussels and their habitat, and;
  • formal mechanisms for compliance and reporting to the Service.

The ALF Plan represents a balanced approach to management of the water of the Tippecanoe River that “looks” downstream toward the human residents and natural resources of the 18 miles of River between Oakdale Dam and the Wabash River, as well as, upstream toward Lakes Freeman and Shafer.
The Tippecanoe River supports one of the most significant and diverse freshwater mussel populations in the United States.  Under the Endangered Species Act, it is the responsibility of the U.S. Fish and Wildlife Service to make sure endangered mussels – even individual ones – are not harmed or killed.  Protecting these mussels protects other aquatic life – fish, for example - and makes the Tippecanoe River a very special place for those who live along it or use it for recreation. 


For more information on the mussels of the Tippecanoe River, visit http://www.fws.gov/midwest/endangered/clams/index.html


The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people. We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals and commitment to public service. For more information on our work and the people who make it happen, visit www.fws.gov/.


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Last updated: September 21, 2016