New Plymouth Water System Rehabilitation Project

This project was designed to achieve compliance with reduced arsenic contaminant levels and correct other system deficiencies including low pressure problems in sections of the distribution system, increased fire flows, and replacement of undersized and deficient piping.  HECO was contracted by the City in 2007 to study their system and develop a water master plan.  The results of this planning effort were used as the basis for the water system project consisting of multiple phases and construction contracts.  New Plymouth Well 9 is a new municipal well providing an additional supply with low levels of arsenic that can be blended with the current system of Wells 7 and 8.  This blending will assure that the arsenic MCL of 10 parts per billion (ppb) can be met.  The aquifer tests conducted on the well shows that it is capable of producing 1300 gpm, but the well is equipped with a 450 gpm pump according to the water rights associated with the well.  Analysis of the aquifer tests shows that the well is 85% efficient which is very good.

Project Included:

• new municipal well
• 250,000 gallon bolted steel storage tank
• tank mixing systems
• online arsenic concentration analyzer
• upgrades to a municipal booster pump station, replacing of pumps and motors
• piping and valving; variable frequency drives
• control system upgrades
• emergency generators
• approximately 20,500 feet of distribution and transmission system piping

Services Provided by HECO Engineers:

• Preliminary Engineering
• Condition Assement
• Project Management
• Construction Documents
• Construction Management
• Survey
• Civil Engineering