KAILUA-KONA — Hawaii County Department of Water Supply is planning to overhaul its testing and inspection processes of incoming deep well equipment in the wake of several premature failures that have led to a water crisis in North Kona.
Keith Okamoto, DWS manager and chief engineer, noted the plans in remarks given at a Water Board meeting in Kailua-Kona Tuesday morning.
“We’re going to have to require these contractors, suppliers or distributors (of deep well equipment) to prove to us before we accept shipment and accept the item that they do this thorough checklist of items in the proper position,” Okamoto said. “Somebody, a third-party licensed engineer or somebody, is going to have to certify that all that was done before we make acceptances. So that’s what we plan to do moving forward.”
DWS does stipulate in some of its contracts that certain types of third-party inspections be conducted, and all recent contracts have included that language, Okamoto said.
But those inspections are more general, testing basic pump efficiency and running full-string tests, which measure equipment function at full speed handling the expected workload.
The department is currently comprising a more comprehensive list of equipment functions it will require tested and certified by an independent third party in future contracts — the checklist Okamoto mentioned in his comments to the Water Board.
That list will include tests of critical dimensions, or specific and unique tasks and strains the equipment will face once installed in Big Island deep wells.
“In the past, we were able to rely on the pump manufacturer’s certification that the pump and motor is good to go,” Okamoto said. “In this particular case, of course, (that was not so).”
When he said “this particular case,” Okamoto was referring to the deep well equipment set for Waimea that DWS decided to divert as a back-up for the Honokohau Deep Well.
Honokohau failed Aug. 13 after being repaired roughly two years before. The replacement motor had never been used and had only been in storage for a month before proving defective.
DWS typically requires such equipment to be vacuum sealed during shipping and while in storage on the island to ensure it’s protected from the elements, which can cause corrosion.
However, this only allows DWS to inspect its hardware visually, a process that is substantially limited in its investigative potential to identify possible equipment deficiencies.
Pre-installation tests are administered immediately before the equipment is to be put to use. Such tests require the equipment be unsealed and placed in a vertical position, the same position in which it will function once installed.
But if a problem is noted, at that point, it’s too late to do anything about it. Equipment must then be returned to the manufacturer for a rebuild or new equipment has to be ordered. This can result in wells remaining offline for months longer than planned.
Several such incidents involving well equipment at multiple sites in North Kona over the last year have been the primary cause of the water crisis the region must now endure.
The most recent instance of this involved the replacement pump and motor diverted from Waimea and meant to spare the North Kona system more hardship. The motor failed a test administered on Hawaii Island by a Centrilift technician only days before it was to be installed at the Honokohau site.
Centrilift manufactured the equipment in question.
The specifics of the technician’s test — which proved the motor unfit for installation, albeit far too late to remedy the situation — are what DWS plans to write into future contracts as a requirement before equipment is ever shipped to Hawaii.
Another potential change Okamoto said the department is considering involves removing equipment from vacuum sealed packaging while still in storage and rotating it, despite the potential of opening the equipment up to corrosion by doing so.
“We need to look at weighing the pros and cons of keeping that in the sealed package,” he said. “We can not store them for too long in that one position, so at some point we need to spin them. If it sits too long in that one position the shaft (ends up bent).”
Not all deep well equipment shipped to the island is vacuum sealed, lending to the idea that periodic rotation is more important than storage methods that keep equipment impervious to environmental factors.
DWS will confer with pump and motor manufacturers to get a sense of how frequently equipment should be spun.
Okamoto said he doesn’t believe DWS storage practices have contributed to the recent rash of equipment failures in North Kona, as the motor diverted from Waimea for Honokohau was vacuum sealed and in storage for merely a month before it was unsealed and found to be defective.
That is only one instance, so while it doesn’t serve as definitive proof DWS storage policies have played no role in malfunctioning deep well equipment, Okamoto believes it a solid indicator.
The precise source of the widespread equipment failures remains unclear.