Gravity Sewer System Rehabilitation, Replacement, and Construction – Package 3

In 2014, DeKalb County, Georgia, was issued a consent decree from the U.S. Environmental Protection Agency (EPA) due to the high level of sanitary sewer overflows that had occurred in the previous 10 years. The Gravity Sewer System Rehabilitation, Replacement, and Construction – Package 3 was identified as a project under the $1.3 billion capital improvements. The County selected Garney and local engineering firm River to Tap, Inc. as their progressive design-build team to perform the gravity sewer system replacements and rehabilitations. 

The scope of work consisted of 29,000 linear feet (LF) of pipe replacement ranging from 8-inch to 30-inch in diameter, 14,000 LF of cured-in-place pipe (CIPP) lining for 8-inch and 18-inch sewer lines, and 112-point repairs with multiple existing pipe materials. There were seven different sub-projects within the overall project with locations throughout the County. Rock excavation using hoe ramming was necessary throughout the project, totaling more than 3,000 cubic yards. The project also included multiple stream crossings, 126 manholes, jack and bore installations, pipe bursting, aerial crossings, stream crossings, and pipe encasements. 

After 60% design, the County made the decision to increase pipe size from 30-inch to 36-inch in certain areas due to capacity modeling updates in the system. Garney worked with the County to provide value engineering (VE) ideas to help meet their budget constraints. This included switching to PVC in areas where ductile iron was originally specified—this VE solution saved the County approximately $450,000, which allowed them to increase to 36-inch diameter pipe in critical areas.  

The project was in an urban area with more than 8,000 LF of the pipeline in the immediate roadway. This required substantial traffic control and bypass setups, including road ramps.

As a result of this project, Garney has established itself as a trusted partner with DeKalb County. The team has worked through multiple challenges, including design changes, hydraulic modeling changes, community outreach, material escalations, and the COVID-19 pandemic.