By Laura Pierce, Sarah Magness, and Morgan Black

Located in Central Ohio, Bokes Creek, Mill Creek, and the Scioto River run through Marysville, Logan, Union, Marion, Delaware, and Franklin Counties.

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We chose this watershed because Northwestern Franklin County, and 30% of Columbus get their drinking water from the Scioto River.

The Scioto River has moderate water quality, that is easily affected by stressors such as pollution.

Upper Scioto Bokes/Mill Creek (Poor) (Good) Source:

What factors are causing changes in the biotic measures in the Upper Scioto River?

When the quality of the habitat (QHEI) of the river is lower, then the fish community (IBI) and the macroinvertebrate diversity (ICI) of that area of the river are reduced.

Chart 1 shows how the quality of the habitat, the fish community, and the macroinvertebrate diversity relate in each sub-watershed.

Based on our data, we found that our first hypothesis was supported. When the QHEI of the river is lower due to poorer habitat quality then the IBI and ICI of that area of the river are reduced.

Siltation is caused by erosion during construction. When silt covers the bottom of the stream the substrate becomes poor. A substrate is the bottom area of the stream. A good stream usually has a rocky bottom, but when the bottom is covered it takes away organisms’ homes.

When the quality of the substrate in an area of the river is poorer, it lacks habitat for macroinvertabrates and fish, then the IBI and ICI are reduced.

Chart 2 shows the relationship between the health of the substrate, and the fish and macroinvertebrate communities.

Our second hypothesis was also supported. When the substrate in an area of the river is poorer, it doesn’t have a rocky bottom. Therefore, it lacks habitat for macroinvertabrates and fish, and the IBI and ICI are reduced.

Land use in the watershed- which includes large tracts of residential, commercial, industrial, and transportation-can adversely affect the QHEI of the river.

The main causes of impairment are nutrient enrichment, habitat alterations, and siltation. This is caused by the human impact from residential, industrial, commercial, and agricultural development.

Nutrient enrichment is the increase of chemicals, for example, nitrates and phosphorous. Nutrient enrichment can be caused by excessive fertilizer runoff from residential yards and agriculture.

Habitat alterations can be caused by development near the riparian zone. This is the forested area along the river that shades the river and provides habitat in order to maintain biodiversity.

Channelization causes streams to be widened,deepened, or straightened by human development. Environmental consequences associated with channelization include bank erosion, increased sedimentation, flooding, and decreased biodiversity.

According to our research, our third hypothesis was supported. Land use in the watershed – which includes large tracts of residential, commercial, industrial and transportation use – can adversely affect the QHEI of the river.

We conclude that the reduction of biotic diversity in the Upper Scioto River and Bokes/Mill Creek is due to human impact. Land development results in the destruction of the riparian zone, erosion, and stream alteration, reducing the quality of the habitat.

We would like to thank the staff at YWSI and OSC. And a special thanks to our group leader, Karen Bachmann. Steve Gordon Kathryn Kelley Leslie Southern Julie Burns Amy Sheaffer Paula Williams