James E. Quarles WTP Reservoir Dam Improvements
Hazen is providing dam rehabilitation design, permitting, and construction services for the James E. Quarles Water Treatment Plant (WTP) Reservoir Dam Improvements project. Upon completion of the initial scope, which included drainage basin analysis, spillway capacity evaluation, field inspections, and 2D breach modeling, the Cobb County Marietta Water Authority requested that Hazen develop a cost-effective option for rehabilitating the dam.
The dam was originally constructed in the early 1950s to serve as the raw water storage reservoir for the James E. Quarles WTP in southeast Cobb County, Georgia. The structure is a ring-shaped earthen embankment that ranges from 10-ft to 35-ft tall, and receives inflow from a pump station on the Chattahoochee River. The dam was classified as a High Hazard structure by the Georgia Safe Dams Program (GSDP) in September 2012. Dam improvements are required to bring the structure into compliance with the GSDP guidelines.
Upgrading the Dam
Working closely with the client, we developed construction drawings and technical specifications, along with an Emergency Action Plan (EAP) and Operation and Maintenance (O&M) Manual.
Working closely with the client, Hazen developed construction drawings and technical specifications, along with an Emergency Action Plan (EAP) and Operation and Maintenance (O&M) Manual, which were submitted to the GSDP in 2016. The final rehabilitation design included adding an articulated concrete block (ACB) overtopping auxiliary spillway to safely pass the Design Storm event, raising a portion of the crest to provide appropriate freeboard, repairing subsidence, and rehabilitating the east corner of the embankment. Subsequent services included developing contract documents and bidding the construction. Hazen will also provide construction administration and oversight.
Project Outcomes and Benefits
- Cost-effective upgrade of spillway capacity through the use of ACB brings the dam into compliance with GSDP regulations.
- Development of an EAP involving 2D breach modeling to better simulate a breach wave for a ring-shaped dam.
- Correspondence with GSDP to ensure the design conforms to all applicable permits and regulations.