Robious 2 MG Elevated Water Storage Tank. Chesterfield County, Virginia.
The Robious pressure zone provides water service and fire protection to approximately 30,000 people. The public water system in this area has an immediate need for additional water storage due to increasing demands and fire protection requirements. Chesterfield County selected WRA to design a new 2 MG elevated composite water tank to replace an existing 1 MG tank and provide an additional one million gallons of storage.
In conjunction with the tank design, an evaluation of tank mixing system technologies for the new Robious Tank was conducted. The inclusion of a mixing system with the tank construction is intended to prevent stratification and the loss of chlorine residual by homogenizing the stored water and disinfectants in the tank.
WRA developed the required plan set to achieve Site Plan approval for the development of the tank site. The required plan set includes a two-phase sediment and erosion control plan, site grading and drainage sheets, MS19 calculations, and a landscaping plan.
A geotechnical investigation was performed by WRA in accordance with the requirements of AWWA D-100 to describe the subsurface conditions, evaluate foundation alternatives and make recommendations for design. During construction, the installation of driven H-piles was monitored by WRA’s geotechnical group.
WRA coordinated with Dominion Virginia Power to extend electrical service to the site. Components of the electrical design include lighting layout, a grounding system, panelboard layout and a cathodic protection system.
Instrumentation and Controls
The I&C system includes a Modicon Momentum PLC and software to incorporate the Robious Tank I/O into the County’s SCADA system. WRA’s design included all components and panels at the tank, modifications at County’s control center, and coordination with the SCADA integrator.