Extensive studies have identified numerous karst features, especially in the area west of Bloomington.  I-69 was routed to avoid the highest concentration of these features.

Where karst features could be impacted, the Indiana Karst Memorandum of Understanding (MOU - which is published as Appendix U in the I-69 Tier 1 Final Environmental Impact Statement) provides for the mitigation of impacts to karst features.  Experience with construction in other high-density karst areas in Indiana (and subsequent post-construction monitoring) indicates that compliance with the Karst MOU results in effective mitigation of karst impacts.  INDOT’s erosion and sedimentation measures have been comprehensively updated to incorporate the most current best management practices for controlling sediment during construction.  More detailed studies will be conducted in Tier 2 to provide an opportunity for further avoidance, minimization, and mitigation of impacts on karst features.  Also, Tier 2 Studies will include a detailed and thorough analysis of secondary (indirect) impacts to water quality for Tier 2 sections where karst features are found.  (Updated 11/14/07)

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