Masters Theses

Date of Award

8-2006

Degree Type

Thesis

Degree Name

Master of Science

Major

Environmental and Soil Sciences

Major Professor

Joanne Logan

Committee Members

Paul Ayers, John Schwartz

Abstract

The Little River (LR) originates in the Great Smoky Mountains National Park (GSMNP), providing drinking water to thousands of residents inBlountCountyas it makes its way to theTennessee River. The upper reaches of the LR watershed have excellent water quality, qualifying it as a hydrologic benchmark river and outstanding national resource. A large outdoor recreation economy has grown dependent on the pristine land and water resources, including whitewater kayaking and rafting, cold and warm water fisheries, hiking, swimming and camping. However, in recent years there has been a documented overall decline in the biological diversity of the LR in the lower reaches outside of the GSMNP boundary, although the reasons are unknown. Sediment is suspected, since high levels can adversely affect water quality, creating an unsuitable habitat for plants and animals. Sediment is a non point source (NPS) pollutant, and is considered the primary cause of water impairment in theUS, and especiallyTennessee. Most watershed restoration planning, including the development of Total Maximum Daily Loads (TMDL) must address sediment pollution.

The objectives for this study were to analyze sediment by measuring 1) Total Suspended Solids (TSS) and turbidity in water collected after storm events, 2) quantify the relationship between TSS and turbidity, 3) examine land use effects on measured TSS, and 4) evaluate long term trends in turbidity data collected at the Maryville (Tennessee) Water Treatment Plant, located near the mouth of the LR. Nineteen single stage samplers were installed in May 2003 at 6 sites on the main channel and near the mouths of 13 tributaries to collect storm event water samples. TSS was measured in mg L-1 using a filtration method, and turbidity in Nephelometric Turbidity Units (NTU) was measured with a turbidity meter. The drainage area of each sampling site was classified using a geographical information system (GIS) as either forest, urban, agriculture or mixed use, depending on the relative areas of each land use, and grouped according to percent imperviousness.

Results from 28 storm events from May 2003 to June 2004 showed a very wide range in TSS, from a low of less than 1 mg L-1 in the pristine upper reaches to a high of 11,108 mg L-1 in one of the more impacted tributaries. The 13 tributaries had higher TSS than the 6 sites on main channel, yet the upper 4 sites on the main channel did not differ significantly from the lower 2 sites. Forested drainage areas had lower TSS than those that were classified as either agriculture or urban. With the exception of one agricultural drainage area, urban areas had higher TSS than agricultural areas. Since it was shown in this study that TSS and turbidity were highly correlated, turbidity data from 1990 – 2004 analyzed at the Maryville Water Treatment Plant was used as evidence of increasing TSS in the LR Watershed, especially in recent years and almost doubling since 2000. Increased development in urbanizing areas of the lower reaches and poor agricultural practices in other tributaries will continue to threaten the water quality of the LR, and must be taken into consideration in any watershed restoration planning.

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