Critical Water Supply Improvements for Pajaro
Details
Client
Pajaro/Sunny Mesa Community Services District
Project Name
Critical Water Supply Improvements
Services
Civil Engineering
Land Survey
Construction Management
Awards
APWA Monterey Bay Chapter, Project of the Year Award, Environment
Overview
The Pajaro/Sunny Mesa Community Services District (District) currently provides potable water service and other public services to the disadvantaged community of Pajaro, California, as well as potable water for eight additional public water systems in surrounding communities. The Pajaro water system serves approximately 450 customers. The water system consists of a single 1,500 gallon per minute (gpm) well; an above-ground, 600,000-gallon welded steel storage tank; and a booster pump system utilizing hydropneumatic tanks.
This system had severely limited operational flexibility. If the existing tank was taken out of service for repairs or if there was an emergency, there was no backup storage for the distribution system. The existing water storage tank is over 35 years old, has degraded and is in severe need of rehabilitation. It was the only potable water storage in the distribution system.
An in-service inspection recommended blasting and recoating of the tank. However, to make these repairs, the existing storage tank would need to be out of service for 6 to 12 weeks, which was not acceptable as the only tank serving the community.
A preliminary design report analyzed the existing tank and provided recommendations for additional storage. Based upon the recommendations, an additional 600,000-gallon water storage tank at the existing tank site was determined the best option to provide additional storage and redundancy for the system.
The goal of the project was to meet requirements for a public water supply system, improve public health and safety, improve water supply reliability, and enhance water system resilience.
The new tank was constructed in the undeveloped area adjacent to the existing water storage tank without taking the existing tank and system offline. The community of Pajaro’s water supply was uninterrupted during construction. The existing tank can be taken out of service for rehabilitation as part of a future project.
The new tank feeds an existing pump station, including two hydropneumatic tanks at the site.
MNS provided civil engineering services, which included engineering planning study development of complete engineered construction plans, and complete construction management services for the construction of the new tank.
