Water and Wastewater Projects
LFA provides design recommendations for Cured In Place Pipe (CIPP) based upon evaluation of host pipe condition (fully or partially deteriorated), depth of groundwater, insitu soils, and pipe ovality. Additional important considerations for project success include bypass pumping plan, maintenance of traffic plan, independent laboratory testing, end seal use, and pre and post lining video inspection.
Since 2010, LFA has observed the installation of over 70,000 lineal feet (and counting) of CIPP Lining ranging in size from 8” to 42” with 20% being 24” or larger. These installations have included trunk sewers, force mains and river crossing siphon pipes. Accurate video inspection and problem resolution are an integral part of the lining process to ensure the desired final result. LFA specifications required leakage testing of the completed CIPP installations to help ensure quality. LFA inspectors have specialized NASSCO (National Association of Sewer Service Companies) CIPP Inspector training focusing on proper installation methods and post video inspection identifying possible concerns with the installation. This training has allowed us to accurately assess installation issues and pursue resolution. We review design criteria and calculations, and ultimate material test results to ensure the end product conforms with the specifications.
The condition of the existing large diameter, 36” northside interceptor was noted to be deteriorating and had significant groundwater infiltration. The 36” interceptor carries combined sewer flow from a large area south of the St. Joseph River. Failure could be catastrophic. Further investigation revealed that both the 18” contributing to the 36” interceptor and the interceptor itself (~3,700 feet) warranted rehabilitation. Structural Cured in Place Pipe (CIPP) lining was the chosen method to avoid an open cut repair due to a tight area with deep pipe located below the water table. Structural CIPP gives the pipe an additional estimated 50 years life and reduces or eliminates groundwater infiltration and root intrusion. Manhole rehabilitation and void remediation were also included in the project. Bypassing the flow, particularly in wet weather, to allow the work to be performed was an extreme challenge for the contractor. With the completion of this project, the City’s interceptor system from CSO 016 to CSO 009 has been rehabilitated protecting this key component of the City’s infrastructure.
LFA performed a comprehensive evaluation of the Whiting Equalization Basin that was originally constructed in the early 1970’s. The Basin is a key component of the City’s combined sewer collection system and helps protect the City from major sewer backups and flooding events. The Basin evaluation included estimating future flows and loads, processes and equipment, electrical systems, instrumentation and controls, operations, and maintenance. Recommendations included improvements to the electrical feed and emergency generator systems, process equipment improvements, building improvements, instrumentation/controls improvements, and basin piping modifications. Estimates were generated for both initial capital and annual operation and maintenance costs.
LFA designed and provided services during construction for this project. The project included installing 615 feet of 20-inch (DR 9) and 615 feet of 24-inch (DR 9) high density polyethylene (HDPE) force main pipes across the St. Joseph River utilizing horizontal directional drilling. Pre-cast concrete valve vault structures for the force main piping were also installed at both ends of the River Crossing.
This project was one of several projects the City of Mishawaka progressed to take advantage of construction in advance of the development. The River Crossing project is located in an upscale subdivision that was in its initial phase of build out. By constructing the project ahead of build out restoration costs, inconvenience, and potential issues with residents were minimized or avoided all together.