Monitoring Activities

Program Overview

The City of Chattanooga Water Quality Program is committed to the fundamental spirit of the Clean Water Act and has developed a variety of programs to effectively address water quality issues within the city limits. A monitoring program has been developed to identify water quality issues and gauge the effectiveness of the City's National Pollutant Discharge Elimination System (NPDES) program. Water Quality Staff utilize a mixture of assessment methodologies to monitor outfalls and in-stream biological, physical, and chemical characteristics of Chattanooga streams as well as the overall habitat. There are nine primary creeks within the city limits: North Chickamauga Creek, Mountain Creek, Black/Lookout Creek, Chattanooga Creek, Citico Creek, South Chickamauga Creek, Mackey Branch, Friar Branch and Wolftever Creek. Each primary creek ultimately drains to the Tennessee River and a variety of unnamed tributaries drain into each of the primary creeks. Water Quality Staff conducts some type of monitoring activity within each of the primary creeks.

Sample Locations Map

In-Stream Monitoring

Currently, the City has five automatic sampler stations permanently located in priority creeks. Permanent stations have been installed at Friar Branch, Poe Branch, Citico Creek, Dobbs Branch, and Black Creek. Each station is equipped to continuously measure flow rate and rainfall. Composite samples are collected and used to monitor base-line conditions within each watershed.

Outfall Monitoring

Water Quality Staff collect water samples from homogenous land use outfalls to quantify the types and concentrations of pollutants entering into the streams. Currently, the City collects samples from five different land uses: Commercial, Heavy Industrial, High Density Residential, Light Industrial and Low Density Residential. Grab samples are collected within the first thirty minutes of discharge (from the outfall) and composite samples are collected over a three hour time period to quantify pollutant loading throughout the intensity of the storm event. Different land uses contribute different types of pollution. Based on the land use and analytical results from the run-off, event mean concentrations of different types of pollutants can be quantified.

Benthic Monitoring

Each year, Water Quality Staff collect macro-invertebrate (bug) samples from two streams, within the city limits. Habitat assessment is conducted at the same time as macro-invertebrate samples area collected. Benthic sampling provides valuable data related to long-term stream health. The type and quantity of macro-invertebrates present within the stream provides an indicator as to the degree to which a particular water body has been impacted. Certain types of macro-invertebrates can only be found in high quality waters, whereas other types of macro-invertebrates are more tolerant and can be found in poorer quality waters.

Total Maximum Daily Load (TMDL) Monitoring

As part of Federal requirements, the Tennessee Department of Environment and Conservation (TDEC) has issued Total Maximum Daily Load (TMDL) limits for a number of streams within the city limits. TMDLs have been issued based on streams that were failing to meet their designated uses (303d listed streams) because of some particular type of pollutant. Currently, TMDLs have been issued for pathogens and habitat alteration. Water Quality Staff sample for e. coli and suspended solids as part of the TMDL implementation plan.