Project Overview
The project consisted of rehabilitation design of approximately 16,700 feet of 36-inch diameter sanitary sewer. The sewer owner, OCWRC awarded the engineering design project to NTH.
The sewer runs through various residential and commercial zones along with regulated Woodland and Wetland areas. Development of a cost-effective lining plan to rehabilitate the sewer while still providing a reduced construction footprint in these sensitive areas was important to both the client and the local community.
Project Scope
The initial tasks included multiple field explorations to aid the rehabilitation design phase. These tasks included a basemap and easement survey, a geotechnical exploration consisting of soil borings at known infiltration locations and a groundwater analysis, an environmental study to identify potential environmental concerns (PECs) along or adjacent to the project corridor, a manhole condition assessment to verify the condition and configuration of the existing manholes, and a Wetland and Endangered / Threatened species study to identify the existing regulated Wetlands and to determine the existence of a Threatened or Endangered species and if conducive habitat within the project site exists.
The data from the field exploration phase was then used to develop a Basis of Design report. Also included in the Basis of Design was a liner alternatives study in which approximately 20 liners were evaluated for inclusion in this project. A hydraulics analysis was also conducted during the Basis of Design phase to assess the hydraulic effects and flow control considerations regarding impacts resulting from a reduction in diameter.
Upon completion of the Basis of Design report, rehabilitation design services were initiated to develop site civil plans, analyze and design sewer lining plans, geotechnical design of temporary earth retention system requirements, develop temporary bypass pumping sequencing and crossings, develop access path routes and details, design geotechnical instrumentation plans, design access structure details, design concrete repair and leak sealing details, and develop traffic control plans where necessary. These designs were utilized to develop Contract Documents (drawings and specifications) for the Bid Package, along with an Engineer’s estimate of probable cost and schedule.
NTH is currently in the final stages of preparing the Bid Package which includes the application for the EGLE Part 41 permit, and permits related to Floodplain (Part 31), Inland Lake and Stream (Part 301), and Wetland (Part 303). In addition to the EGLE permits, NTH has begun coordination and application for construction permits from various government and private agencies having jurisdiction for this project.
Client Benefit
NTH evaluated approximately 20 different lining manufacturers / trenchless sewer lining technologies to create a competitive bid proposal to drive down project costs while also developing low-impact access options to efficiently line approximately 3 miles of sewer running through the city of Novi. NTH is producing contract documents that are able to increase competition due to the inclusion of multiple types of lining technologies while limiting environmental impact due to the selection of key locations along the alignment for construction access.
