Planning with Vision

The Hawaiian island of Kauai is meeting the challenges of its geography, climate and remote location while revitalizing its aging water system.
Planning with Vision
Craig Shirai feeds 1-inch soft copper pipe through a hole bored by the Grundomat horizontal boring tool from TT Technologies.

Interested in Trucks?

Get Trucks articles, news and videos right in your inbox! Sign up now.

Trucks + Get Alerts

he County of Kauai Department of Water, charged with the task of supplying water across the island of Kauai, Hawaii, is working to unify and modernize its water system under its comprehensive Water Plan 2020. The plan, devised in 2000, aims to upgrade aging water infrastructure, unite separate water systems and ensure an abundant supply of quality water for the future on firm financial footing.

The department currently operates 11 unconnected water systems ranging from Haena in the north to Kekaha in the south. While the island covers more than 560 square miles, the water distribution system covers 68 square miles, primarily along the island’s coast.

The department monitors, operates and maintains 50 deep well pumping stations, 19 booster pumping stations, four tunnel sources, 58 storage tanks, 75 control valve stations and over 400 miles of pipeline serving approximately 66,000 residents. All department revenues are derived from water sales.

Unique supply challenges

“The island has unique challenges in securing its water supply,” says Bill Eddy, deputy manager and engineer with the department. “One side of the island receives 13 inches of rain per year, while the other is the wettest location on Earth, receiving 455 inches annually. This is also the oldest of the main Hawaiian islands and the most eroded. Fresh rock is more permeable, but old rock doesn’t offer good geology for wells, so we still need to practice water conservation despite the heavy rainfall in parts of the island. Our water supply relies 85 percent on groundwater and 15 percent on surface water.”

Water is pumped into storage tanks, then transmitted through a pipe system ranging from 3/4 inches in diameter for those lines serving just a few customers on isolated routes to 24-inch mains. The distribution system is comprised of everything from galvanized steel to asbestos cement, cast iron, ductile iron, concrete cylinder and PVC. Pipes range in age from brand new up to 90 years old.

A thorough survey of the system conducted in the late 1990s revealed deficiencies in pipe condition, along with concerns about system capacity, water supply levels, storage capacity and the financial needs of the system.

The survey rated the condition of the overall system as poor, noting the deterioration of pipelines and mapping a series of vulnerable mainlines located in remote areas with poor access that impeded repair and maintenance.

That study preceded Water Plan 2020, a thorough roadmap to revitalizing the water system.

“I was the director at the Maui Water Board at the time that Water Plan 2020 was being developed,” says David Craddick, current manager and chief engineer at Kauai. “I watched with some amazement at the number of community meetings that were held by manager Ernest Lau at the time. The community was heavily involved in developing the plan, and that’s why the plan has been implemented without much further debate in financing the projects.”

To date, $125 million of a proposed $600 million has been spent on the program with the department making good progress on its construction schedule.

Current work involves a continuing emphasis on replacing pipelines.

“Each of the old pipe materials continues to display its own weakness,” notes Eddy. “We’re seeing failures in the joints and rubber gaskets of asbestos cement pipe that have caused us a lot of trouble. Cast iron lines become brittle and are subject to full circle cracks, often due to tree roots or ground shifts. PVC reaching the end of its service life is subject to lateral cracks, particularly the thinner material installed decades ago.”

Ductile iron is faring much better, with occasional pinholes presenting the worst problems. Eddy notes that the island is fortunate to possess largely neutral soil. While aggressive soils in Oahu and Honolulu are notorious for attacking water infrastructure, the exterior of iron pipe fares well in Kauai, making ductile iron the replacement material of choice.

Mains buried deeper

The Kauai team is now burying new mains deeper than in the past. “Some of the older pipes were buried less than 3 feet deep, and we’re now adding 3 feet of cover to the top of the pipe,” Eddy says. “We’re enforcing the new standard to see if it has an effect on breakage.”

Sections of older pipelines are also being aligned with public roads as they are replaced. “From the 1920s to the 1950s, they were typically aligned along the shortest route, which caused them to be installed through pastures, forests and private property,” Eddy says. “Access and maintenance has been a problem with these pipelines.”

In-house crews tackle mainline replacement jobs up to 500 feet in length. The work is primarily dig-and-replace.

“We have also done several horizontal directional drilling (HDD) projects using both HDPE and fusible PVC C900,” Eddy says. “Most HDD work has been done at stream crossings, a few of them under emergency conditions when existing pipelines were damaged during severe winter storms. We did one slipline job on an old 27-inch steel pipe, sliplined with 16-inch HDPE.”

Outside contractors are engaged in larger projects, often shipping in workers and equipment by barge.

Switching to RFPs

During fiscal year 2011-12, the department switched from a traditional low bid process to a request for proposal system. While the major transition temporarily slowed the pace at which projects were advertised, the new approach is expected to provide higher-quality contractors that will assist the department in remaining on schedule and on budget.

The department currently has no leak detection program in place, because it has found it challenging to attract qualified technicians to the island. Kauai has already purchased SubSurface LD-12 listening devices, FCS Permaloggers and ZCorr correlators, but currently uses its SCADA system to detect most large leaks.

Repair crews are split into two teams, with field crews handling pipelines and distribution located along the coast, and plant crews handling wells and storage tanks located further inland toward the mountains.

“There are no direct roads to some of those tanks, so it could take an hour and a half by four-wheel drive,” says Eddy.

The department operates a fleet of Ford Rangers and F-150s, 250s, 350s and 450s to ply the island’s rough terrain.

Crews use a backhoe with a 4-in-1 bucket combo and a skid-steer loader to deal with 90 percent of leaks. The small size of the equipment works well on narrow residential roads and minimizes damage to asphalt, which comes at a premium price on the island. Pipelines are generally repaired with splices and stainless steel clamps.

“We also recently acquired an older Vactor truck and we’re rehabilitating it,” Eddy says. “We intend to use it for potholing, trench dewatering, and valve and meter vault cleaning.”

The department continues to work on a slate of pipeline and tank projects within the 2020 plan. One near-term goal involves interconnecting the individual water systems, which will not only provide redundancy, but also reduce pumping costs where the market price of electricity hovers around 45 cents per kWh.

Replacing experience

Maintaining the engineering, inspection and fiscal staff to implement Water Plan 2020 has also presented a challenge to its completion.

“A large number of longtime experienced staff members retired within the past 10 years and much of their knowledge and expertise went out the door with them,” Eddy says. “We’ve struggled to replace the institutional knowledge of the people who retired. We also struggle to recruit new professionals, especially young engineers. I suspect that the overall number of college students graduating with civil engineering degrees is relatively low nationwide. We’ve also had trouble recruiting new graduates who were born and raised on Kauai to return to Kauai. I suspect that young graduates prefer to go out and see the world before returning to their home base.”

A $60 million Build America Bond was recently issued for a combination of water system replacement and water system expansion projects. However, budgeting continues to pose a challenge.

“We conducted a water rate study over the past two years and found that the ratepayers are currently paying all that they can handle,” Eddy says.

Despite its challenges, the goals of Water Plan 2020 remain firmly in place.

“It’s been a valuable tool for us for the past 12 years,” Eddy says. “Each of the individual programs within the plan — the asset replacement program, the water system expansion program and the financial plan — have been updated several times since 2000. However, the original plan is the foundation and anchor that we continue to count on.”


Comments on this site are submitted by users and are not endorsed by nor do they reflect the views or opinions of COLE Publishing, Inc. Comments are moderated before being posted.