Big Walnut Creek Sanitary Sewer Trunk Extension

DLZ was responsible for providing a preliminary plan for an extension of the Big Walnut Creek Sanitary Interceptor Sewer in Northeast Franklin County, Columbus, Ohio. The preliminary design consisted of an alignment evaluation for approximately 30,000 LF of the sanitary extension trunk sewer. It also included conducting preliminary planning of several subtrunk sewers to outlying areas.

The Big Walnut Creek sanitary interceptor sewer project included several other tasks, some of which are stated below

• Tributary area delineation
• Population projection, alignment, and profile evaluation
• Hydraulic calculations
• Geotechnical and hydrogeological investigations
• Construction method evaluation including conventional tunnel, micro-tunnel, and open-cut options, as well as combinations thereof
• Risk Analysis, and cost estimations

Additionally, DLZ provided a detailed design for the trunk extension and two subtrunk extensions. Detailed design for the trunk extension included 15,000 LF of 72” finished diameter tunnel including 6 vertical shafts ranging from 40 VF to 180 VF, one connection structure, and approximately 600 LF of soft ground tunneling and hand mining. The detailed design for the subtrunk extensions includes 5,126 LF of 27” to 21” sewer and 1,905 LF of 24” sewer, both of which, constructed by open-cut methods.