In coordination with GDOT’s GA-400 Express Lanes project, City of Atlanta Department of Watershed Management (DWM) agreed to relocate roughly 5200 LF of 48” water transmission main outside of the GA-400 right of way. Benchmark Management teamed up with Ruby-Collins for this design-build (DB) contract. The alignment follows Old Alabama Road in the City of Roswell beginning at the Chattahoochee River, which required extensive permitting.

The overall project delivery schedule was extremely aggressive so DWM ordered 70% of the material while writing the RFP to minimize material procurement time. Benchmark was responsible for figuring out where the material fit into the design, which added a level of difficulty. The project was also broken into phases to begin construction on the bulk of the pipeline while still working on design and permits for other phases.

The project was completed within the contract deadline, made possible by advanced material procurement, the design-build contract, and the phased approach to construction and permitting.

The rehabilitation and repair of approximately 6,500 linear feet of various size existing sanitary sewer pipes, ranging in diameter from 8 inches to 36 inches, located throughout the northern and central airfield within SIDA, as well as outside of SIDA at South Cargo. The rehabilitation is classified as either Grade 4 or Grade 5 based on the NASSCO PACP scale. The chosen method for rehabilitation is the Sekesui spiral wound liner repair method, which is expected to reduce the need for extensive bypass systems on the airfield, can be installed during low-flow, off-peak hours overnight, and minimizes impacts to regular airport operations.

The North Fork Peachtree Creek Tank and Pump Station Project will construct an off-line temporary 15-million-gallon storage tank for peak wet weather sewage flow, supported by a 75 MGD pump station. During significant wet weather events, peak flow will be diverted from the North Fork trunk sewer to the off-line storage tank. The stored flow will be returned to the trunk sewer after the wet weather event. The goal is to significantly reduce the number and volume of sewer overflows along the entire Peachtree Creek trunk sewer system, including eliminating sewer overflows during a 10-year, 4-hour storm and smaller back-to-back storms.

Benchmark Management is the engineer-of-record (EOR) for the 6 culvert replacement projects. Benchmark Management provided the Clayton County Water Authority with hydrological study, hydraulic modeling, and detailed engineering design. We also provided engineering support during construction.

Phase B & C of the Upper Proctor Creek Capacity Relief Project – Rodney Cook, Sr. Park in Historic Vine City has successfully completed the task of separating the combined sewer system to route stormwater down to the Cook Park retention pond (Phase A) within the Vine City neighborhood. The pond was designed to manage 150 acres draining down to Boone Blvd and Vine St, including parts of Georgia World Congress Center. With these phases now completed, the overall project is poised to reduce localized flooding and provide sewer capacity relief to benefit both Vine City and English Avenue neighborhoods. BenchMark Management played a crucial role in this achievement, providing the engineering, design, hydrologic and hydraulic modeling, as well as permitting for the installation of approximately 9,000 linear feet of large diameter storm pipe. This work also included the replacement of curb inlets, concrete curb and gutter, concrete sidewalk, pavement repair, and resurfacing. The engineering team utilized the latest versions of AutoCAD Civil 3D, Autodesk Storm and Sanitary Analysis, and ArcGIS in the process.

Honey Creek PS, Force Main and Gravity Sewer Improvements is a design-build project with a Guaranteed Maximum Price (GMP) of $24.4 million for DeKalb County Department of Watershed Management. The 7.5 MGD sewer pump station’s wet-well is 40’ deep with 2,154 gal/ft storage capacity. This pump station is a reinforced cast-in-place 24’ x 12’ rectangular structure which includes four (4) 1,800-gpm VFD-equipped submersible pumps operating at 272-feet of head, screening and screw conveyor system, odor control system, electrical building, pump valves in valve vault, site utility piping, and a 5-ton monorail hoist system. The work also includes the installation of 17,500 linear feet of 18-inch ductile iron pipe force main, site grading, erosion control, electrical & instrumentation work and the condition assessment of 14,500 linear feet of 24” – 48” gravity sewer trunk.

The Consent Decree Program Management Team (CDPMT) is comprised of technical, professional, and managerial staff that provide program management services to DeKalb County Department of Watershed Management. The CDPMT supports the County’s overall objective of reducing wastewater collection and transmission system sanitary sewer overflows (SSO). The key tasks the CDPMT are responsible for include Consent Decree monthly reporting; project status reporting; program development and management; implementing the Capacity, Management, Operations, and Maintenance (CMOM) Programs which consist of the Sewer Mapping Program, System-wide Flow and Rainfall Monitoring Program, System-wide Hydraulic Modeling Program, Priority Area and Ongoing Sewer Assessment and Rehabilitation Programs (PASARP and OSARP), Sanitary Sewer Overflow Rehabilitation Projects oversight including construction inspections, Contingency and Emergency Response Plan (CERP) Program, Fats, Oil, and Grease (FOG) Management Program, Maintenance Management System (MMS) Program, Collection and Transmission System Training Program, Infrastructure Acquisition Program, and the Financial Analysis Program.