Total Maximum Daily Load

Keeping Residents & Visitors to Michigan Safe
Keeping residents and visitors to Michigan safe while pursuing their recreational interests in Michigan’s waters is a Michigan Department of Environment, Great Lakes and Energy (MDEGLE) priority.  To help attain the goal of enhancing recreational waters, Michigan continues to expand its efforts to reduce E.coli contamination of its surface waters through the establishment of the Total Maximum Daily Loading (TMDL) for E.coli.  The TMDL represents the maximum loading that can be assimilated by a water body while still achieving its designated Water Quality Standard (WQS).
Escherichia coli (E.coli) is used as an indicator for fecal contamination. Sources of E.coli can include untreated human sewage, failing septic tanks, livestock, pets, wildlife and illegal connections from home sewer systems to surface waters. As the level of E.coli increase, so does the risk of illness upon contact or incidental ingestion of the affected waters.

The TMDL requirements established for the City of East Lansing’s water bodies are the same as those established for all other surface waters in the State of Michigan that are impaired by E.coli.  The ultimate goal of the TMDL as established in Michigan is to identify problem areas, address sources of E.coli statewide, and provide guidance to restore these waters.  

A TMDL establishes the allowable level of pollutants for a water body based on the relationship between pollution sources and in-stream water quality conditions.  TMDLs provide a basis for determining the pollutant reductions necessary from both point and nonpoint sources to restore and maintain the quality of water resources.

Currently the E.coli TMDL only applies to the Red Cedar River Watershed (RCRW) area within the City of East Lansing.  However, it is likely that the TMDL requirement for E.coli will someday be extended to the Looking Glass River Watershed portions of the City of East Lansing.

Established E.coli Limits
Water bodies are evaluated for the Total Body Contact (TBC) and Partial Body Contact (PBC) recreation designated uses using E.coli as an indicator for other harmful pathogens.  This is consistent with USEPA recommendations for fresh water recreational water quality criteria for protecting human health.

The State of Michigan has officially established the limits for its E.coli TMDL to be a concentration based standard as follows: “For this TMDL, the WQS of 130 E.coli per 100mL as a 30-day geometric mean and 300 E.coli per 100mL as a daily maximum to protect the TBC use are the target levels for the TMDL reaches for May 1 through October 31, and 1,000 E.coli per 100mL as a daily maximum year-round to protect the PBC use.”

City of East Lansing TMDL Implementation Plan
The City of East Lansing submitted the E.coli TMDL implementation plan (PDF) dated January 2019 as part of its NPDES Permit Application.

The plan evaluated the potential sources and causes of E.coli contributions from within the City’s borders and determined that wildlife, pet wastes, and illicit connections were the most likely sources of discharge.  Furthermore, the highest potential for and likelihood of E.coli being discharged into the Red Cedar River Watershed and Looking Glass River Watershed are from pet wastes and wildlife.

The City evaluated and identified specific BMPs to address the identification, evaluation and elimination of the various sources of E.coli that could potentially discharge into the Red Cedar River Watershed and Looking Glass River Watershed

The City then drafted a monitoring plan with a two stage approach to meeting the City’s TMDL goals.  First the City will continue to work with other communities and entities within the Red Cedar River Watershed to monitor the overall health of the entire watershed.  Second, the City of East Lansing will implement a plan to analyze and track the actual contribution of E.coli from the City to the Red Cedar River by means of end of pipe sampling.  The City will also endeavor to undertake an informal plan to analyze and track the contribution of E.coli from the City to the Looking Glass River if and where practical.