2003 Fairfax County Regional Science and Engineering Fair

The abstract below was written by the student. The Northern Virginia Soil and Water Conservation District made no editorial changes.

Abstract

The project's purpose is to confirm that Dyke Marsh, a freshwater tidal wetland, can support and sustain a healthy population of aquatic or semi-aquatic plants and animals. With all of the short-term highway construction and large-scale development projects as well as the number of potential long-term pollution sources such as wastewater treatment facilities, power plants, and drainage systems that could impact the preserve, I am concerned that the water and soil quality in Dyke Marsh will deteriorate and the plant and animal life found there will be adversely affected. I hypothesize if water and soil samples are of good quality, the Marsh can support a healthy wetland habitat.

Over a three-month period, water samples from six locations were tested using a standard mercury thermometer, titrimetric, colorimetric, and visual analysis for temperature, pH, nitrate-N, phosphate, ammonia-nitrogen, dissolved oxygen, salinity, alkalinity, chloride, carbon dioxide, and turbidity. These tests indicate the presence of waste materials, decomposing matter, fertilizer and detergent runoff, hydrogen levels, and other conditions that could seriously affect marsh life. Soil samples from three sites were tested using colorimetric chemical reactions for pH, phosphorous, nitrogen, and potassium.

Water test results compared favorably to standards published by the Environmental Protection Agency and the Fish and Wildlife Service. Soil test results indicated healthy soil for marsh plants. My conclusion is the current water and soil conditions will continue to support a healthy wetland. However, continued monitoring is recommended due to the surrounding environmental influences that have the potential to threaten the preserve's health.