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Watershed Study - Summary

The watershed ("Little Mouse Creek") on the north side of the Longview Campus of Metropolitan Community College has been studied since Fall Semester of 2003 by over 200 students in biology classes taught by Dr. Stephen Reinbold. The study is for the purpose of making recommendations about the best way to control environmental damage to a small, intermittent stream and to Longview Lake which receives water from the Little Blue River watershed impounded above the dam.

The general hypothesis being tested is that trees protect and improve water quality in watersheds. Water quality is examined in terms of abiotic and biotic components. The stream receives nitrates from fertilizers used throughout the watershed, which potentially cause eutrophication (over-enrichment) and consequent degradation to Longview Lake.

The stream catches leaves from trees in the immediate watershed, providing the main source of food for consumer organisms in the stream, ultimately broken down to simple inorganic molecules by aerobic and anaerobic metabolic processes. The study investigates the interactions among the inputs to the steam, their effects on organism abundance and diversity, and outputs to Longview Lake. The model being tested is based on scientific literature which contains the hypothesis that leaves are necessary for organism abundance and diversity and will remove nitrates from the stream.

The field experiment conducted yearly involves collecting leaves in the winter or previous fall, securing them by nets in the spring, and sampling abiotic and biotic data in the spring, and again in the summer when removing the nets.  Methods and data for the first eight years of the experiment are stored in the Archive.  A summary of trends showing graphs over nine years of the field study comparing experimental sites and control sites with regard to nitrate, oxygen, and number of organisms can be found at summary.htm.

Because of the vicissitudes of doing a field study, an amphipod laboratory experiment was conducted to simulate the field experiment. The enzyme Oxyrase® was used to decrease oxygen concentration and cause denitrification.

Both field and laboratory experiments will be repeated to further test the model of trees protecting watersheds, and it is hoped that more specific recommendations for protecting the watershed will be forthcoming.

Dr. Stephen Reinbold

Last Modified: 6/1/18