A regular correspondent from Pukalani wrote in to suggest solutions to the perennial summer water shortages Upcountry and traffic congestion between the west side and the rest of the island. Neither are practical, or from my POV, desirable, the author either unaware of or unconcerned with issues of cost, geology, or ascetics.

Waikamoi Diversion Dam

Waikamoi Stream Diversion Dam (C. Holmberg)

Water: While most Maui residents get their drinking water from deep wells in Kahalewai (the West Maui Mountains), Upcountry Maui depends on rainfall on the northwest slopes of Haleakala, which is diverted by a system of ditches to water treatment plants. Rainfall and the collection system hasn’t kept up with the growing population, with the result that there is a long waiting list for new water meters, and calls for voluntary water conservation every summer.

The County Board of Water Supply is currently planning construction of a couple of new Upcountry water storage ponds totaling 300 million gallons, the $60 to $100 million cost to be shared by the County, State, and Federal Governments.

Kahakapao Reservoir

Kahakapao Reservoir, a 100mg water storage pond (C. Holmberg)

The correspondent, Mr. Vierra, suggested that the County should skip the reservoirs, and construct “some kind” of dam to catch the water currently running into the ocean.

Piiholo WTP

Piiholo Water Treatment Plant (C. Holmberg)

What he doesn’t realize is that very little surface water of the northwest water shed between Haiku and Nahiku reaches the ocean, because the East Maui Irrigation (EMI) and Maui County Waikamoi catchment systems intercept it. The problem is finding a place to store excess supply for use during the slack times. Attempting to dam one of the steep, narrow valleys carved into the northwest slopes of Haleakala for storage would result in a drawn out EIS fight, be at least as expensive as the proposed reservoirs, and leak like a sieve through the porous lava behind a dam.

Highway Tunnel: As the resident and visitor population of Maui has grown so has the volume of traffic on two lane Honoapiilani Highway linking west Maui with the rest of the island. Rush hour traffic is a daily chore, and forest fires or accidents along the Pali can leave the road closed for hours.

Mr. Vierra is also one of a number correspondents who have suggested creating a short cut by boring a tunnel through Kahalewai (West Maui Mountains). He suggests running one from Waikapu Valley to Olowalu. Others have suggested one from Iao Valley to Lahaina.

Tetsuo Harano Tunnels, H-3 freeway, Oahu, Hawai'i (Flickr, CC:)

Tetsuo Harano Tunnels, H-3 freeway, Oahu, Hawai'i (Flickr, CC:)

Regardless of the advances in tunnel boring technology over the last couple of decades, a tunnel from Central Maui to the west side would be a massive and hideously costly undertaking. It would require huge concrete viaducts at either end, almost certainly in the form of an H-3 Freeway-like, four-lane highway up a couple of valleys. It would be expensive to maintain, increase motor vehicle traffic on existing roads and spur added suburban sprawl.

H-3 Viaducts In Halawa Valley

H-3 Viaducts In Halawa Valley (Wikipedia)

Even if we to brush away those concerns, no one will be building tunnels much longer than the current Pali tunnel, unless someone has a lead on several billion dollars. To get the H-3 freeway through the Koolau Mountains on Oahu required two 5,000-foot-long, 50-foot-wide tunnels. To drill through Kahalewai would require at least double the length, in addition to massive raised viaducts at the approaches. The H-3 only needed to follow one valley. A similar effort on Maui would require a freeway along two narrow, undeveloped valleys, key parts of the West Maui watershed, ribbons of concrete which would contribute to spoiling the visual appeal of the island.

The H-3 cost about $160 million per mile in current dollars, excluding the tunnels, financed through Daniel Inouye’s power as a ranking U.S. senator, under the rationale of connecting a couple of major military installations. That kind of money could pay for six lanes around the pali – not that I’m pushing that idea – with money left to throw in a monorail.

I find myself rebutting this tunnel fantasy in letters to the editor every year, to the point where I think we need an FAQ. Anyone favoring the idea should start by informing themselves of the history and cost for the H-3, then decide if they want to proceed with the discussion.