QUALITATIVE HABITAT EVALUATION INDEX

Brief Summery:

Regulatory activities under the Federal Water Pollution Control Act of 1972 and its 1977 and 1987 amendments require knowledge of the potential fish or biological community that can be supported in a stream or river. A procedure for relating stream potential to habitat quality would provide some insight into how habitat might affect biological expectations in a given water body. The QHEI is designed to do just that by providing a measure of the qualitative habitat corresponding to the physical features that affect fish and invertebrate communities. In other words, the monitor is to take the fish's point of view and decide "would I like to live here?"

The presence of organisms in a stream is strongly related to the physical and chemical characteristics of the stream. The habitat provides shelter for organisms, attachment sites to grow on, turbulent areas for mixing with oxygen, and areas to hunt or graze on algae. Shifts in the make-up of the community are responses to nutrient availability and habitat changes. Organisms intolerant of pollution (natural or man-made) tend to be found in habitat having a lot of cover, a variety of flows, lots of different substrates that are clear of silt and sand, and low levels of toxic material in the water. Generally, pollution tolerant organisms are very specific in their life needs and do not have the versatility to adapt to a wide range of environmental conditions. On the other hand pollution tolerant organisms tend to be associated with slow moving water, live much of their life in silt and sediment and tend to exhibit an adaptability to a wide range of environmental conditions.

The QHEI data sheets are divided into several metrics, and each of the metrics is broken down into individual components. For each component, you will assess the status of your river and assign a score based on that status. The score for each component is shown in square brackets for each state of the stream. When you enter data into the data form, the computer will assign the correct score and add it up in the appropriate fashion. This program was created to help explain what these individual components are and to help you identify them in the field.

METRICS WITHIN THE QHEI:

1. SUBSTRATE



1. Type
2. Substrate Origin
3. Substrate Quality: Silt
4. Substrate Quality: Embeddedness


2. IN-STREAM COVER



1. Type
2. Amount


3. CHANNEL MORPHOLOGY



1. Sinuosity
2. Development
3. Channelization
4. Stability


4. RIPARIAN ZONE AND BANK EROSION



1. Riparian Width
2. Flood Plain Quality
3. Bank Erosion


5. POOL/GLIDE AND RIFFLE/RUN QUALITY



1. Max. Depth
2. Morphology
3. Current Velocity
4. Riffle Run Depth
5. Riffle/Run Substrate
6. Riffle/Run Embeddedness


6. GRADIENT



1. Gradient and Stream Size



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INTERPRETING THE QHEI

The Qualitative Habitat Evaluation Index gives an estimate of the suitability of a stream segment to meet warmwater habitat for aquatic organisms. This is the usual "natural" habitat type in Ohio. When each metric is scored, and the scores are added up, you will calculate an aggregate QHEI. It is interpreted as follows:


• QHEI > 60: Stream segment suitable for Warmwater Habitat without use impairment.
• QHEI between 45 and 60: Stream segment may meet Warmwater Habitat in some circumstances, but it may show a level of impairment that requires classification as Modified Warmwater Habitat.
• QHEI between 32 and 45: Stream segment meets Modified Warmwater Habitat.
• QHEI < 32: Stream segment may be suitable for Modified Warmwater Habitat only if the watershed is greater than 3 square miles. Even then, this may not be possible. Where Modified Warmwater Habitat is not possible, the stream segment is classified as a Limited Resource Water.



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