SCH Number 2025010509

Project Info

Title

Main Intake Canal Siphons Project

Description

The District is pursuing the construction of the two reinforced concrete pipe or box siphons, each connecting to the MIC. The Project proposes to install two new reinforced concrete pipe or box siphons adjacent and upstream of the existing siphons at each site. The new siphons will address the structural concerns of the existing siphons and will also enhance the maximum capacity to approximately 1,100 CFS. The Project will be completed in multiple construction phases. The initial phase will involve clearing and grubbing outside of the St. Johns and Kaweah River channels at the individual siphon sites, which could include minor vegetation removal. Upon completion of the first phase, the second phase of Project construction will be the excavation of the sending and receiving pits, one pit on either side of the Rivers at each siphon site. These pits are utilized for the jack and bore drilling installation method. In the sending pit, a boring machine and auger will drill into the earth beneath each river, installing pipe casing along the way to the receiving pit. It is anticipated the sending and receiving pits will be gravel or rock lined to stabilize the operation of the pipelines. This phase will also see the installation of head walls and wing walls on upstream and downstream sides as well as trash racks on the upstream side of the siphon intakes. The third phase of the Project will consist of reconditioning the water flow into the new siphons and into the MIC. The existing box culvert siphons will remain in place once construction of the new siphons is complete. A new bulkhead and control gate(s) will be installed to direct flow to the new siphons, unless high flows require the use of the existing siphon. Keeping the existing siphons in place in the riverbeds will provide added erosion protection for the new siphons in the Rivers by stabilizing the river bottom sediment in place. Benefits associated with the Project include: • Enhanced facility and system reliability • Increased facility capacity • Protection of functionality of the St. Johns River and Kaweah River • Surface water reliability for irrigation and groundwater service

2 documents in project