The Project proposes to construct a new lift station at the MHP, a new force main from the MHP to the MCWD Sphere of Influence (SOI) boundary at American Ave and Chestnut Ave, and a gravity sewer main as master planned to the point of connection with the existing MCWD sewer collection system. This includes extending the 15-inch sewer main in Maple Avenue from the WWTF to Malaga Avenue, a 12-inch sewer main in Malaga Avenue from Maple to Chestnut, then south in Chestnut to American Avenue. Extension of the gravity sewer line would allow for service of the area without the requirement for existing private lift stations which serve a few properties along the proposed pipeline route. Extension of the new 12-inch pipeline in Malaga Avenue would include the abandoning the existing 6-inch sewer main in Malaga Avenue and connection of the existing services to the new sewer main. Extension of the 12-inch diameter pipeline in Malaga Avenue would also allow for the connection of several properties that are presently served by septic tanks and leach fields. Similarly, extension of the new 12-inch sewer main in Chestnut Avenue south of Malaga would include the elimination of the existing 6-inch pipeline and relocation of the existing services to the new sewer main. The Project would also include improvements to the existing MCWD WWTF. This includes demolishing the equipment in the Dissolved Air Flotation (DAF) basin, installing one recirculating pump in the 3rd aeration basin, installing oil and grease removal in grit chamber, modifying the air piping, installing recirculation flow meter and sludge flow meters, removal of berms between disposal pond 1, 2 and 5, replacing one influent pump, replacing one blower, and constructing new circular clarifiers. Once the connection to the MCWD is completed, the existing MHP WWTF would need to be properly demolished.
The proposed force main would be four (4) inches in diameter and approximately 4,000 linear feet (LF) long. The force main will include crossing of two Fresno Irrigation District Canals (Oleander Canal and Washington Colony Canal) by either jack and bore or directional drilling. The 15-inch gravity sewer main would be approximately 2,300 LF. The 12-inch gravity sewer main would be approximately 5,300 LF. The design includes twenty (20), 4-ft diameter manholes along the gravity sewer main alignment.
Consolidation Process
The Project would not require MCWD to update its SOI and annex the MHP. While the MHP is outside of the MCWD SOI and service area, MCWD would be willing to enter into an Outside Agency Service Agreement (Agreement) pursuant to Government Code Section 56133.
Operations during Construction
Impacts to both treatment plants operations would need to be minimized during construction. This would be primarily accomplished by effective scheduling of work activities, with some temporary bypass of flows.
Installation of pipelines, absent the final connections to the existing systems and discharges to the MCWD WWTF, would be completed concurrently with other tasks. Traffic control, dust control, and worker protection would be accomplished throughout the duration of construction so as to minimize impacts to the MHP, MCWD, and the public. Detours of traffic and exclusion of pedestrians from the work area are routinely managed by construction contractors and would be coordinated with the MHP and MCWD for work affecting the respective facilities.
It is a basic requirement that each downstream portion of the improvements be completed prior to upstream components being placed into service:
MCWD WWTF disposal ponds must be ready to receive treated wastewater for
disposal prior to the MCWD WWTF discharge pipeline being placed in service.
MCWD WWTF process improvements must be complete to ensure wastewater
discharges meet WDRs prior to receiving flows from the MHP.
The MCWD gravity pipeline needs to be completed and ready to receive flows
prior to the MHP force main receiving flows from the MHP lift station. Diversion of
the MHP collection system to the new lift station can only take place after all prior
portions of the project are complete.
The MHP collection system must be connected to the new lift station prior to
decommissioning and demolition of MHP WWTF and ponds.
The MHP lift station would be sited in a manner such that it can be completed offline from the collection system without impacting the operation of the existing plant. On completion of the lift station, a manhole would be constructed to intercept the collection system upstream of the MHP WWTF. When all downstream components are complete, flows would be diverted and the MHP collection system connection to the MHP WWTF would be severed. Decommissioning of the MHP WWTF would then proceed.
The effluent disposal facilities improvements at the MCWD WWTF, consisting of the pond modifications, can take place concurrently with work at the MHP and other areas in the Fresno County right-of-way (ROW).
Improvements and repairs within the plant, such as replacement of an influent screw pump, replacement of a blower, addition of a recirculation pump, modifications to the anoxic basin, and installation of clarifiers can be accomplished by utilizing existing redundancy in the facilities to isolate work areas or installation of temporary bypass piping and pumping.
The new circular clarifiers would need to be sited outside the footprint of the existing plant and connection of piping coordinated with the treatment plant operator to minimize disruption to the operation of the rectangular clarifiers, at least one of which would need to remain in service throughout.
Construction Schedule
Construction is anticipated over approximately 24 months. Generally, construction would occur between the hours of 6 am and 6 pm, Monday through Saturday, excluding holidays. Construction would require temporary staging and storage of materials and equipment onsite.
Equipment
Construction equipment would likely include excavators, backhoes, graders, loaders, saws, compactors, hauling trucks, and water trucks.
Operation and Maintenance
The newly installed gravity sewers and all infrastructure within the MCWD existing boundaries would be owned, operated, and maintained by MCWD. The MHP sewer collection system upstream of the lift station would remain the responsibility of the MHP. The lift station would be situated on MHP property, leaving the MHP responsible for its operation and maintenance.
