Beneficial Use Impairment 6:
Degradation of Benthos

The numbers, health and diversity of macroinvertebrates inhabiting the stream beds in our watersheds are inseparable from the health of fish populations.

The graph above shows the status of the HUC12 subwatersheds relative to the delisting target for the particular stream type.

Yes, it's too small to read. So...either click here to download a pdf that'll be easier to see, or scroll down to see the line graphs for each individual subwatershed.

What the delisting guidance says -

In the riverine areas upstream from the lake affected waters (lacustuary or fresh water estuary), the average of the Invertebrate Community Index (ICI) values within the assessment unit do not significantly diverge from state biological criteria;


In lake affected waters (lacustuary or fresh water estuary), the average of the L-ICI values do not diverge from state guidelines.

1Ohio EPA has determined the non-significant departure value for riverine ICIs to be 4 points and the targets presented in this table reflect the non-significant departure from Ohio WQS.

2Non-significant departure for the lacustuary ICI value has not yet been determined.  A study is currently underway in to determine lacustuary criteria in Ohio.  Once the study is complete, Ohio EPA will review the results and determine if the current target should be revised.

3Targets for Limited Resource Waters (LRW) are based on benchmarks as there are no criteria in Ohio WQS.

4 The ICI target for lacustuaries is based on an Ohio EPA study in 1994 that identified 34 as a value considered an attainable goal for the Lake Erie lacustuaries given the current altered habitat conditions in the absence of excessive sedimentation and water column enrichment or toxicity.


  • Assessment units are the 12-digit HU, Large River Assessment Unit (LRAU) or other agreed upon stream segment or subwatershed.
  • If waters have more than one designated use (i.e., Lacustuary and LRW or MWH) then the lowest target applies.
  • This BUI will not be evaluated for ICI in waters that are routinely dredged as it is unrealistic for a healthy benthos community to be restored under these conditions.

Progress toward delisting


Of the subwatersheds that we currently have credible data for, 73% of them, or 8 of the 11, are above the target scores for this BUI.

However, there are many subwatersheds with no data or very few sampling sites. We have developed a plan to fill the sampling gaps, which would allow us to have a more realistic assessment of conditions.

The currently-sampled subwatersheds with the lowest average habitat scores the Little Cuyahoga River and Doan Brook (note that the Doan Brook HUC12 includes Dugway Brook.)

With targeted efforts, this BUI could be delisted within 5 years.

Status by 12-digit Hydrologic Unit Code (HUC12)

In the Cuyahoga River Area of Concern, these geographic boundaries are sometimes different than the boundaries defined by topography.

The following graphs show the target scores (dotted lines) and the scores of the most recent sampling.

Click here to download the tables showing the data and sources on which the graphs are based.

Click here to download the graphs as a pdf file.

This product or publication was financed in part or totally through a grant from the Ohio Environmental Protection Agency and the United States Environmental Protection Agency, with funds from the Great Lakes Restoration Initiative. The contents and views, including any opinions, findings, or conclusions or recommendations, contained in this product or publication are those of the authors and have not been subject to any U.S. EPA or Ohio EPA peer or administrative review and may not necessarily reflect the views of either Agency, and no official endorsement should be inferred.

 Cuyahoga River Restoration
formerly Cuyahoga River Community Planning

is the local 501c3 facilitating organization that raises funds, manages programs and projects, including this website, and coordinates, staffs, and assists the Advisory Committee.

1299 Superior Ave. E • Cleveland, OH 44114
216-241-2414 •