Bryson Kuwahara has pitched to the newly elected governor a plan for a “flexible, portable safe lava tube bridge” he says will ensure access to lower Puna once the lava crosses key arterial roads in the area.
Kuwahara is planning a $20 million shopping center on his nearly 10 acre lot near the intersection of Kahakai Boulevard and Pahoa Village Road. Construction commenced earlier this year after council members approved a commercial rezoning for Kuwahara’s property at 15-2714 Pahoa Village Road.
Since construction started, Pahoa has been threatened by lava flowing from the Pu’u O’o vent of the Kilauea volcano.
Kuwahara wrote the governor on Dec. 5 and submitted an open letter to Big Island Chronicle urging residents who support his idea to contact the governor and both state and county officials to encourage them to implement it.
“What we are trying to do is to ask the State of Hawaii to support and fund the idea to set up a bridge over the lava so the people of Pahoa would have access to Highway 130,” Kuwahara writes. “This bridge would be built mostly on private land with the approval signed by the property owners involved.”
His pitch offers scenarios for both a one-lane road and a two-lane road.
“After the flow has formed a thick enough crust,” which Kuwahara estimates to be about a week with no break outs, “bring in a large excavator that is able to level the road alignment and extend over the hardened surface.”
“Then, haul in coarse rough 6″ plus red cinder to crate a two feet thick leveled roadway surface, slowly reaching out with the excavator boom and building a road.” Kuwahara refers to Ken Hon, professor of geology and volcanology at UH Hilo, who maintains that rough red cinder has many air pockets and void that dissipates heat.
Kuwahara states that one of the most readily available pre-engineered platform flat rack frame is the 8′ x 40′ x 2′ thick Matson deck used for ocean transports.
“These frames can carry the weight of heavy truck traffic,” he notes, adding that they have been used for building bridges.
“Think how strong these frames must be to withstand the punishment of being stacked very high and all of the motions of a ship at rough seas,” Kuwahara writes.
He suggests attaching three lengths of the frames in a row with a heavy chain connection or a hinge system, creating a “120′ flexible two join deck for vehicle traffic.”
“Because lava can inflate and deflate with volume flowing underneath the surface, the joints can flex,” he writes.
He notes that according to Hon, the tube system will develop somewhere in the lava field within a month of the flow. “This is the most dangerous area to cross over,” Kuwahara writes. “Depending on the volume of lava coming down, the top area of the tube is very weak and unstable. This tube can be full or empty on the top part, creating a void that can collapse with weight.” He suggests that the tube’s location be identified through thermal imaging equipment, and then the three section deck he envisions can be placed and centers over the tube. “Install some kind of combination of thermal blankets, stainless pipe and water cooling system in this hot area,” he writes.
Kuwahara offers schematics to illustrate his vision.
He states that the cost for one flat rack frame is $10,000. Six frames would be needed for a single-land road, so the cost would be approximately $60,000. Twelve frames would be needed for a double-land road, so the cost would be about $120,000.
“Should the lava tube have a breakout above the bridge area, it is possible to lift and move the entire frame, using three bulldozers,” Kuwahara writes. “Attach two bulldozers with chains on the ripper, lift up, pull and using the third bulldozer to push from the rear, to after, away from oncoming lava. Let the lava pass and cool. Level roadbed and lay cinder base again. Then pull back and reuse the framework over the tube system again.”
Kuwahara maintains that his bridge idea will work because the deck will be very strong.
“Even if the ground does settle in the tube area, the bridge will not collapse. More sections can be added, if needed,” he states. “The deck frames are readily available from Matson or the mainland. Rough red cinder is also available eight miles away from the present lava flow.”
The length, width and roughness of the top surface terrain of the lava field will determine the cinder cost, but a 30-yard truckload costs $400, Kuwahara notes.
He also points out that the system is reusable when another layer of lava flows.
Kuwahara has been in contact with Hilo Councilman Dennis Onishi and Kevin Dayton, the executive assistant to Mayor Billy Kenoi. He says he and others are in the planning stages to build an experimental bridge over the lava inundated Cemetery Road in Pahoa.
With the advice and expertise of Hon, engineers with the County of Hawaii Public Works, and the Hawaii Island staff of the Department of Transportation, “we can learn, improve and come up with the best solution for the Puna Lava Bridge.”
Kuwahara hopes that if the experimental bridge proves successful, the state and the county will construct portable bridges on Pahoa Village Road, Highway 130 and Kahakai Boulevard in the event lava inundates those roads.
An excavation contractor for the past 39 years and a four-generation resident of Pahoa, Kuwahara is hopeful he can be part of a team “in saving access to Puna and its lifestyle.”
He notes that he and his crew assisted in the construction of the Railroad Avenue bypass, which is expected to be used once lava crosses Highway 130 and blocks access to lower Puna.
“With my fellow Puna contractors, we have enough excavators, bulldozers and dump trucks, to assist in whatever direction the county and state decide to take,” Kuwahara writes. “Saving access to Puna is vital to its recovery and well being for everyone who lives in the area.”
To weigh in on the matter, call Ige at (808)586-0034, or submit testimony via fax at (808)586-0006 or via mail to the Executive Chambers, State Capitol, 415 S. Beretania St., Honolulu, HI 96813.
Pooch Harrington is a writer in Puna.