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Maria Creek Watershed

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The Maria Creek Watershed covers approximately 97 square miles in southwestern Indiana and is located in Sullivan and Knox counties. The four subwatersheds included in the Total Maximum Daily Load (TMDL) report are Marsh Creek, Headwaters Maria Creek, Tilley Ditch, and Cotton Branch.


Past surveys of the Maria Creek Watershed were conducted in 1993, 1999, 2004, and 2009 which included monitoring for fish communities, macroinvertebrate communities, and water chemistry through several IDEM monitoring programs. Impairments currently identified in the watershed include E. coli, dissolved oxygen (DO), and impaired biotic communities (IBC). Potential pollution sources contributing to these impairments include nonpoint sources from agricultural lands and pastures, rural run-off, wildlife, as well as point sources from straight pipe discharges and home sewage treatment systems.

Parameters To Be Addressed

IDEM will complete a comprehensive sampling program in the watershed that will be based on the current impairments. A total of 18 sites will be assessed for general chemistry, nutrients, habitat, and fish and macroinvertebrate communities. A comprehensive list of all parameters will be referenced in the approved work plan.


A public kickoff meeting was held to introduce the project and solicit input on December 10, 2019 from 5:00 PM - 7:00 PM at the Sullivan County Fairgrounds, 1301 E County Road 75 North, Sullivan, IN 47882.

A Water Monitoring Demonstration Field Day is scheduled for October 14, 2020 from 4:00 PM – 6:00 PM at the Emison Mill County Park in Bruceville, IN. The park is located approximately 0.5 mile south of the intersection of SR 550 and N Emison Mill Road. Due to the COVID-19 pandemic, masks are required at all IDEM events. In the event that a participant refuses to wear a mask, the event will be canceled.

A draft TMDL public meeting will be held in the summer of 2021 once the comprehensive sampling program is complete.

The TMDL Report

  • The TMDL Report is to be completed by Autumn 2021.

Watershed Characterization Monitoring 2019-2020

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