Natural setting shapes repair approach

Originally Published 8/26/2015

Goal is limiting environmental impact

DAVIDSON COUNTY'S SURROUNDING environment is an ever-present factor in how the Clean Water Nashville Program plans construction repairs on aged and defective wastewater infrastructure.

The Westchester Drive Rehabilitation project, located in the Belshire community between Belshire Drive and Dickerson Road in northern Nashville, is a prime example of the efforts to minimize construction impacts and limit environmental disturbances.

This project will rehabilitate approximately 3,850 linear feet of sewer pipe that runs along and crosses underneath the North Fork of Ewing Creek, a Whites Creek tributary. Cracked 10-, 15- and 18-inch diameter pipes within this local system have been allowing rainfall, creek water, and groundwater to seep in and take up capacity in the sewer system. This kind of infiltration may result in flow rates that exceed the capacity of the sewer system, resulting in sanitary sewer system overflows.

The program team evaluated two options to update the infrastructure in the project area. One option was to dig out the extensive pipe system and install new infrastructure, an approach that could cause considerable disturbance to the creek, including removal of established vegetation along the waterway.

The second alternative, which was selected, was to rehabilitate the current sewer system through a method known as “cured in-place pipe lining.” In this trenchless rehabilitation method, a pipe lining is placed in the existing sewer and is cured to form a rigid pipe within the existing sewer that effectively seals cracks and prevents water infiltration.

Rehabilitating the existing sewer pipe infrastructure rather that replacing it with new pipes will achieve the same outcome while minimizing impact to the North Fork of Ewing Creek.

Westchester Drive Rehabilitation construction began in June and is scheduled to be complete in November 2015.