The objective of this task is to quantify with depth the density and type of bottom and subbottom sediments up to depths of 15 ft below the bottom surface along the Clinch River and Poplar Creek, TN. The Clinch River study area extends from River Mile (RM) 0 at the confluence with the Tennessee River to RM 21.7 at the Highway 95 Bridge. The Poplar Creek study area begins at the confluence with Clinch River (RM 0) and extends 2.2 miles upstream to the first highway bridge. The results will supplement sediment core samples previously taken in each study area by providing continuous profile line coverage along the entire length of the study area. This information will facilitate the accurate positioning of any future sediment samples as may be required by the Clinch River Environmental Restoration Program.
An array of geophysical instruments will be utilized to meet the objectives of the investigation. The basic suite of systems include:
This equipment will be used to produce the necessary seismic energy to obtain reflection signatures from the bottom and subbottom lacustrine sediments. Primary channels of acoustic data will be acquired with a digital data acquisition system. Data are collected in near real-time during the survey allowing continual data quality control. Data analysis and processing will be performed post-survey at the WES. Acquisition and interpretation of traditional 'shades-of-gray' analog reflection records will be performed concurrently with the digital acoustic impedance techniques.
A dual frequency side scan sonar will be towed during the survey to provide increased areal bottom coverage and detect any possible dredging or navigation hazards. Although entirely qualitative, the side scan sonar data can be interpreted to differentiate bottom sediments in terms of material types, such as sands versus clays, in a rapid, continuous manner.
Proposed Survey. The proposed survey along the Clinch River and Poplar Creek are outlined as follows:
