Masters Theses

Date of Award

12-1985

Degree Type

Thesis

Degree Name

Master of Science

Major

Environmental Engineering

Major Professor

Bruce A. Tschantz

Abstract

A small stream near Huntsville, Alabama contains considerable amounts of DDT contaminated sediments.{1)(2)(3) This stream, called Huntsville Spring Branch, flows into the Indian Creek which in turn flows into the Tennessee River. Ten miles of stream is contaminated with varying degrees of DDT. The erosion of these contaminated soils cause higher than normal concentrations of DDT in the water column of the stream. This has caused elevated concentrations of DDT in the local fish population.

In order to reduce the DDT content of the fish, the stream morphology was studied so that methods to reduce erosion of the contaminated soils could be examined. A literature search was conducted and only a few studies involving contaminated sediment were found. However, some computer programs for calculating sediment erosion were found to be applicable to the project and were investigated.

A computer program called HEC-5 (4) was used to identify potential scour and depositional areas of the stream. The potential amount of sediment erosion from the areas of potential scour was quantified with the respective DDT content at each site. In this way, a relative ranking of potential sources of DDT to the water column was made. The modeling results showed that a small section of the stream was identified as being the major source of DDT due to a combination of stream morphology causing high degree scouring and the high DDT concentrations in these soils. Rerouting the stream around this mile long reach should substantially reduce DDT in water concentrations.

Other remedial measures were evaluated for their effectiveness in reducing DDT water concentrations. A difference in DDT erosion between high pool and low pool conditions was predicted by the model and confirmed with field data. Although current sediment transport theory cannot accurately predict the amounts of sediment that can erode from a stream, computer modeling was found useful in studying and understanding stream morphology, and in ranking the relative effectiveness of possible remedial measures.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS