The Mill Creek study was conducted in 2011, and a study report, titled the Biological and Water Quality Study of Mill Creek and Tributaries 2011, was published in 2012 by MSD’s consultant, the Midwest Biodiversity Institute.
The study included the entire mainstem of the Mill Creek from the border of Butler and Hamilton counties to the Ohio River, the West Fork of the Mill Creek, the East Fork of the Mill Creek, and tributaries to each. This watershed encompasses a drainage area of 170 square miles in a highly urban and industrial landscape.
As part of the study, standardized biological, chemical and physical monitoring and assessment techniques were employed using Ohio EPA methods and criteria. Sampling was conducted at 92 sites between June and October. The biological sampling and analysis was performed by Level 3 qualified data collectors and under a study plan approved by Ohio EPA. Seventy-six of the 92 sampling locations were evaluated against the warmwater habitat (WWH) or modified warmwater habitat (MWH) designation, while 16 of the sampling locations were evaluated against the Primary Headwater Habitat (PHWH) designation.
Highlighted findings of the study, as compared to a 1992 Ohio EPA study of the Mill Creek, are as follows:
Click here for an interactive webmap showing the Aquatic Life Use classifications and attainment status for the sample locations.
A body of water is in "attainment" if its chemical, biological and physical (habitat) integrity is maintained (as evaluated against water quality standards). Attainment means that a body of water capable of supporting a particular biological community is in fact supporting that biological community (e.g., trout in a cold water stream).
A body of water is in "partial attainment" or "non-attainment" when chemical, biological or physical indicators only partial attain the required condition for that parameter or are below the required condition.
A body of water is considered impaired if it is not in attainment or is in partial attainment.
Causes for impaired sites include sedimentation, habitat alterations, elevated polycyclic aromatic hydrocarbon (PAH) compounds, chlorides, nutrients, ammonia, metals, low flow and low dissolved oxygen (DO). The sources include urban runoff, altered hydrology, combined sewer overflows (CSOs), leaks in the sewer system, Wastewater Treatment Plants, storm sewers, Ohio River backwater and hydromodification.
Click here for an interactive webmap showing the Recreational Use classifications and attainment status for the sample locations.
E. coli (primary contact 30-day geometric mean criterion) was exceeded at 43 of 45 sites sampled. For the E. coli sampling results, download the Biological and Water Quality Study of Mill Creek and Tributaries 2011 report.
Sources of fecal bacteria in the Mill Creek are likely related to CSOs, sanitary sewer overflows (SSOs), urban runoff, and deteriorating sewage collection systems in the older urban areas.
MSD's Customer Call Center:
1600 Gest St.
Cincinnati, Ohio 45204
The free Adobe Reader is required for some downloads.