Stream Habitat Assessment

B. Water Quality Data

5. Stream Habitat Assessment

The fourth index listed in the example on Big Darby is labeled QHEI (Qualitative Habitat Evaluation Index). This index evaluates the quality of a stream segment’s bed material (sand, silt, cobbles), the buffer area, stream gradient, the presence of pools, rifles and runs among other things. The QHEI is used to help determine the aquatic life use designation as included in the equation for aquatic life use designations.

Figure 90: Ohio Aquatic Life Use Designations
Designation	Typical Characteristics of each Designation
Excellent Warmwater Habitat (EWH)	Streams capable of displaying an unusually diverse amount of natural habitat and unique or rare organisms.
Warmwater Habitat (WWH)	Typical Stream in Ohio that exhibits natural stream features and supports diverse and healthy fish, bugs, and vegetation
Modified Warmwater Habitat (MWH)	A stream that is essentially in a permanent state of modification such as a county maintained ditch or channel impacted by urbanization
Limited Resource Water (LRW)	Very small streams that typically dry up during the year that have a very limited biological potential

General or Typical Scores

· MWH – less than 45

· Potential WWH greater than 45 but less than 60 (requires closer analysis of attributes)

· WWH – 60

· EWH – 75 or greater

In the example of Big Darby Creek, the QHEI score is a 74.5 which places it the EWH range.

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Last updated: November 18, 2008.