In the past, Paulding County, Georgia has relied on the Cobb County-Marietta Water Authority to supply safe drinking water to its residents. With the county's population expected to double over the next 25 years, an independent water supply was critically needed. In 1999, the effort began when citizens approved the development of a new water supply reservoir. Finally, in October 2015, after years of effort involving numerous federal and state governmental agencies, including the U.S. Army Corps of Engineers, the county was granted a 404 permit allowing for construction of the Richland Creek Reservoir Water Supply Program. Once completed, the 305-acre Richland Creek Reservoir will store 3.43 billion gallons of drinking water for its residents.
Construction of an access road to the new reservoir required the installation of a structure able to cross a live stream without impacting the waterway and while providing support for the new roadway above. A 26' x 13' MULTI-PLATE® single radius arch, 184' in length, was selected from Contech Engineered Solutions as the best bottomless solution. Brad Cole Construction selected Pinnacle Design/Build to provide the turnkey design and the project commenced. EXPRESS® Foundations, also from Contech, were utilized on the project to provide support for the bridge structure. The precast foundation system blended the speed of precast with the economy of cast-in-place, while further expediting the speed of installation.
"The original concept required construction of a double barreled culvert for the crossing which would have required obtaining a flood easement on the adjacent property as well as requiring purchase of additional stream mitigation credits," stated John Dean, Project Engineer, with Arcadis. "By selecting the bottomless MULTI-PLATE arch, the County was able to avoid both."
Once the MULTI-PLATE structure was assembled on-site, the soil was compacted first around the sides, and then over the top of the structure. The compacted soil interacts with the structure providing maximum stability and support for construction of the roadway above.
"With the MULTI-PLATE structure's ability to be assembled in the field, it provided an efficient alternative to traditional cast-in-place concrete structures and was assembled in a condensed time frame," stated Judd Murphy, Vice President of Sales and Marketing with Pinnacle Design/Build Group.
More than $80 million in low-interest loans and grants was secured from the State of Georgia to fund this project, the largest in the county’s history. The entire project, consisting of a new dam, a reservoir, a water treatment plant, two major pump stations, 20 miles of pipeline, and other distribution system improvements, is expected to be completed by the end of 2019.
"This reservoir project will secure an independent and sustainable water supply source for the County," concluded Murphy.