Williams County, Ohio
CT Consultants provided site engineering services for the construction of two new service plazas to replace the existing facilities in Williams County. Each service plaza consists of a service plaza building, a truck maintenance facility, a gas service station, and parking for automobiles, truck and travel trailers.
The layout of program elements on the existing site was based on the Turnpike’s prototype service plaza design. CT Consultants provided an evaluation to revise the prototype design to give consideration to the interrelationship of vehicular and pedestrian patterns throughout facility. A change from the prototype included a shift of emphasis for pedestrian traffic from the main entrance door to the shared emphasis with the food vendor’s entrance by developing visual cues and reconfiguring the parking lot traffic patterns. Pedestrian routing was also emphasized through pavement types, signage, and plantings.
Off-site utilities needed to service both proposed plazas were also studied and a preliminary determination of the drainage plan for both proposed sites was determined in order to define the space requirements for storm water detention and storm water quality requirements. Utilities included a waterline, a water storage tank, a sanitary pump station, natural gas service and electrical service. Many of these utilities required extending existing systems a significant distance (miles) to the Service Plaza sites.
The storm water management system for the new service plazas included approximately 13,200 feet of new storm sewers and four detention basins to control the discharge of both the water quantity and quality to the adjacent receiving streams. The construction of the detention basins will require significant earthwork. The excavation from the detention basins will be placed on the site as embankment to create a balanced site with minimal soil import or export. The two sites require approximately 400,000 cubic yards of excavation and embankment. The detention basins are dry basins with inlet/outlet structures and low flow swales. The water quality treatment for the parking lot runoff was addressed with the implementation of four hydrodynamic separators located ahead of the four detention basins to remove sediment, oil, debris and other stormwater pollutants.