Myriad Engineering provided sewer design services for a 10,000 LF sewer pipeline project in the historic downtown area of Mariposa to increase reliability for impacted businesses and residents. Based on video survey, we determined the VCP joints failed due to extensive root intrusion that also caused displacement. Additionally, a review of the original as-built drawings showed that the pipes in many areas were very shallow based on the depth of hard rock. Operations staff shared that the pipe bedding had eroded over time, and in many places the pipe was resting on the hard rock. We analyzed trenchless methods for replacement, including lining and pipe bursting.
We developed a replacement analysis report based on conditions and cost and determined that open trench replacement was the best solution due to the number of pipe displacements, root intrusions, and the need to address pipe bedding. As part of the design, we prepared a desktop hydraulic analysis to ensure minimum velocities to prevent debris buildup along the pipe, developed pipe crossing details to identify utility conflicts and minimum separation requirements, and provided several bid schedules for construction phasing and to address future increase in pricing due to economic conditions.
Scope of services:
- Engineering design
- Hydraulic calculations
- Design details & specifications