Water Distribution and Sewer Collection
Pakpour Consulting Group provides a full range of water distribution and sewer collection engineering services including conceptual analysis, final design, and construction support services. With our experience as District Engineers for three water and sewer districts, we have developed innovative and practical solutions to meet various design challenges. Our staff maintains the hydraulic model for our districts using WaterCAD®
Tank Retrofit and Recoating
Town of Hillsborough | Hillsborough, CA
Situation: In the early 2010s, the Town of Hillsborough conducted a comprehensive seismic and coating analysis of their water storage tanks. The study indicated their tanks needed extensive rehabilitation and, in some cases, complete reconstruction. The Town turned to Pakpour Consulting Group (PCG), a trusted partner with decades of experience rehabilitating water tanks.
Special Challenges: PCG worked closely with Town’s operation staff to ensure the tank improvements met the Towns operational needs. In addition, PCG retained a structural engineer to analyze each tank site’s seismic vulnerabilities and to propose improvements.
Service Overview: Since 2014, PCG has served as on-call engineers for the Town of Hillsborough and prepared plans, specifications, and cost estimates for multiple water tank rehabilitation projects throughout the Town. The existing tank coatings on all of the tanks were beyond their useful service life in addition to requiring appurtenance upgrades and rafter replacement due to severe corrosion. Appurtenance upgrades included guardrails, roof hatches, level indicators, ladders, overflows, center vents, sampling stations, and landing areas. Projects included:
Skyfarm III Tanks Recoating and Retrofit: Recoating and appurtenance retrofit of two 700,000-gallon water tanks. Completed in 2016.
Tournament Tanks Recoating and Retrofit: Recoating and appurtenance retrofit of two 600,000-gallon water tanks and rafter replacement. Completed in 2017.
Skyfarm II Tanks Improvements: Recoating and appurtenance retrofit of two 65,000-gallon water tanks. Completed in 2018
Marlborough Tanks Improvements: Recoating and appurtenance retrofit of two 225,000-gallon water tanks along with roof replacement. Completed in 2020.
About the Town of Hillsborough: Located on the San Francisco Peninsula, Hillsborough is home to some of the most exclusive residences in the Bay Area. The water distribution system consists of 4,200 service connections, 107 miles of distribution system, 18 storage tanks, 14 pump stations, and 16 pressure zones.
Taaffe/Elena/Moody Roads Water Main Replacement
Purissima Hills Water District | Los Altos Hills, CA
Situation: The water main along Taaffe Road was one the last remaining Asbestos Cement (AC) water mains within Purissima Hills Water District (PHWD) along with the last remaining section of its backbone infrastructure to be upgraded. AC water mains are brittle and subject to severe damage during seismic events. PHWD’s backbone infrastructure is designed to be able to move water North to South throughout the district after a major seismic event. The existing water mains consisted of 6- to 8-inch asbestos cement and cast-iron pipe. In some instances, the water mains were more than 7 feet deep creating challenging maintenance situations. In addition, the design incorporated transferring water from an adjacent water purveyor which would enter just downhill of these improvements.
Special Challenges: To improve water movement between Zone 2 and Zone 3, Pakpour Consulting Group (PCG) conducted extensive hydraulic modeling to determine appropriate pipe sizes while considering fire protection needs. The new water mains were located primarily along highly-travelled thoroughfares used by local residents and cyclists. This triggered extensive community outreach to residents, bicycle shops, and forums, in order to generate detailed traffic detours to ensure public safety. Portions of the site were also located near known cultural resource sites requiring specialized monitoring and construction worker training.
Services Overview: Since 2004, PCG has served as PHWD’s District Engineers responsible for comprehensive all-inclusive services including planning, financial analysis, design, construction management, and final commissioning. Upon project completion, PCG collaborates closely with District maintenance staff to ensure the project meets its design intent and goals. For the Taaffe/Elena/Moody Road Water Main Replacement, PCG provided start-to-finish services for the installation of approximately 5,600 LF of 12-inch DIP, 3,700 LF of 8-inch DIP, all associated appurtenances, fire hydrants, and pavement restoration.
About Purissima Hills Water District: Located on the San Francisco Peninsula, PHWD is a Special District serving 6,400 residents and 10 institutional customers in Los Altos Hills.
Meadowlark Sewer Siphon Project
City of Pleasanton | Pleasanton, CA
Situation: As a part of the City of Pleasanton’s annual sewer improvement projects, the City required the installation of approximately 800 LF of 8-inch fusible polyvinyl chloride (FPVC) sanitary sewer to facilitate maintenance on a “parallel” existing 8-inch vitrified clay pipe (VCP) sewer.
Special Challenges: The existing 8-inch VCP sewer crosses under I-680 and an adjacent creek (Arroyo De La Laguna) and operates as a siphon due to the depth of the crossing. The new 8-inch FPVC sewer alignment began at an existing 20-inch VCP sewer, crossed under the creek and freeway, and connected to the existing 8-inch VCP sewer. The connections at each end required the construction of a new 8-foot manhole structure at a depth of approximately 15 feet. The City required a maximum sewer length of 825 LF between the manhole structures to allow use of their existing cleaning equipment. The creek and freeway crossings required agreements and encroachment permits from the California Department of Fish and Wildlife, Caltrans, and Alameda County Flood Control and Water Conservation District Zone 7, each of which added constraints to the project. In addition, the existing sewer serves a large residential area and was required to remain in continuous operation throughout the construction. PCG selected horizontal directional drilling (HDD) for the installation of the 8-inch FPVC sewer to allow continuous operation of the highway and to avoid the need to enter the creek area.
Services Overview: Since 2013, PCG has served as on-call engineers for the City of Pleasanton. For the Meadowlark Sewer Siphon Project, PCG provided design and construction support services for the installation of approximately 800 LF of 8-inch FPVC sewer and 12-inch FPVC casing by horizontal direction drill and approximately 75 LF of 10-inch HDPE sewer by pipe bursting. PCG prepared the various agreement and permit applications and coordinated with processes with the agencies. PCG also provided bid assistance and construction support.
About City of Pleasanton: Incorporated in 1894, Pleasanton has a population of more than 70,000. In 2005 and 2007, Pleasanton was ranked the wealthiest middle-sized city in the United States by the US Census Bureau.
San Jose Water Company As-Needed Engineering Services
San Jose Water Company | Santa Clara County, CA
Situation: After a thorough evaluation of their underground infrastructure, San Jose Water Company (SJWC) determined that it must accelerate the replacement of its water main to provide safe and reliable service. Consisting of approximately 2,400 miles of water main throughout the heart of Silicon Valley, SJWC committed to replacing 1% (or 24 miles) of its entire system annually at a cost of $50 million. Constructed of ductile iron (DI), the newly installed pipes would be in service for the next 100 years.
Services Overview: Since 2018, Pakpour Consulting Group (PCG) has served as on-call engineers for SJWC. PCG is responsible for the preparation of plans and bid item quantity estimates in conformance with SJWC standards. PCG’s services also included preparation of water main shutdown plan and coordination with the State Water Resources Control Board’s (SWRCB) Division of Drinking Water and jurisdictions where the projects are located including Caltrans.
Notable Projects:
La Mar Drive Water Main Replacement: Replaced 3,600 LF of existing pipe. Project was located in the City of Cupertino. Completed in 2019
Mt. Hamilton Water Main Replacement: Replaced 2,600 LF of existing pipe. The project was located entirely within Caltrans’ right-of-way in unincorporated Santa Clara County. Anticipated to be completed in 2024.
Maya Way Water Main Replacement: Replaced 2,900 LF of existing pipe. Project was located in precipitous area of the Town of Los Gatos.Completed in 2021.
Pacifica Drive Water Main Replacement: Replaced 3,500 LF of existing pipe. Project was located in the City of Cupertino. Completed in 2022.
About San Jose Water Company: Founded in 1866, SJWC is an investor-owned public utility and serves water to more than 1 million people in San Jose, Campbell, Cupertino, Los Gatos, Monte Sereno, and Saratoga.
