Engineers recommend new boat ramp for lower Puna after eruption

Local News

Honolulu –  While it’s technically possible to remove sand and create a channel to the Pohoiki Small Boat Ramp on Hawai‘i Island’s lower Puna coast, an engineering study commissioned by the DLNR Division of Boating and Ocean Recreation (DOBOR) finds that it would be very expensive and full of uncertainties associated with sand movement and costal processes continuing in and around Pohoiki Bay.

Representatives from Sea Engineering Inc. visited Pohoiki on May 1, 2019 and then produced a 32-page-long report which states, “The recent volcanic activity and lava flow has resulted in the formation of hundreds of thousands of cubic yards of black sand and cobbles at the lava-ocean interface, which has been carried southward by coastal currents and now completely fills Pohoiki Bay, rendering the existing Pohoiki boat ramp land-locked and useless.”

In order to re-open the Pohoiki Boat Ramp a channel would have to be excavated through the new beach and maintained open by shore-perpendicular jetties. Given the continuing production of volcanic sand, and the dynamic and variable waves and currents along the coast, a jetty on both sides of the channel is considered necessary to insure the continued navigability of a channel through the beach. Sea Engineering estimates it would cost approximately $37.9 million to restore the Pohoiki ramp.

The estimated cost for a new facility at Mālama Flats is estimated at $14.5 million and would include:

  • A 295-foot long, 100-foot wide, and 6-foot deep entrance channel excavated inland.
  • A 0.6 acre launching and turning basin, 6 feet deep.
  • 830 linear feet of rock wave absorber along the entrance channel and basin.
  • A single lane concrete boat launch ramp, 18 feet wide and 128 feet long.
  • A 24-foot wide, 60-foot long concrete ramp approach pad. • A 30-foot long, 5-foot wide concrete loading dock, complete with fenders and mooring hardware.
  • A 100-foot long, 5-foot wide, ADA compliant loading dock approach walkway.
  • Approximately 1,330 linear feet of lava rock (CRM) retaining wall, 2 to 4 feet high, to permit raising the ground elevation in the ramp vicinity. 
  • Material excavated from the channel and basin would be used as compacted fill to create a uniform +10-foot elevation backshore support area.  This is necessary to prevent occasional flooding of the ramp facility by wave runup.
  • A two-lane, 24-foot wide, asphalt access roadway approximately 680 feet long.

DOBOR will need to work with the Federal Emergency Management Agency (FEMA) to secure appropriate funding to build a new ramp and associated facilities and when and if that happens will have to obtain appropriate permits and hold public hearings or informational meetings with local boaters and the community.

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