A new Waikīkī Beach improvement project to help beach erosion is kicking off next week. The project includes construction of a 95-foot-long sandbag groin and the transfer of 700 cubic yards of beach sand from the Diamond Head swim basin of Kuhio Beach. The groin and beach sand will serve to stabilize the Diamond Head (South east) end of Kuhio Beach park fronting the Duke Kahanamoku statue. The purpose of the project is to fix an erosion hot spot in the far eastern corner of Royal Hawaiian Beach until such time a larger master planning effort for Waikīkī Beach can be completed.
The planned groin project consists of the placement of a 95-foot-long by 18-foot-wide by 4.3-foot-high sandbag groin extending seaward perpendicular to the beach at location 140 feet west of the Kuhio Ewa swim basin groin. Approximately 60% of groin will be buried within the beach face and extend into the ocean approximately 30-40 feet. The project includes the retrieval and transfer of 700 cubic yards of sand from the east (Diamond Head) swim basin area to nourish the eroded beach after construction of the groin is complete. A partial beach closure at Kuhio Beach for the construction staging area is required, but community access to and along the shoreline will be maintained always.
The groin will be constructed of 68 geotextile ElcoRockÒ sand bags, weighing about 10,000 pounds each when full of sand. The sandbags require 225 cubic yards of sand and the sandbags will be filled on the beach. These bags will be stacked to form a stable structure with sloping crest elevation sufficient to prevent sand transport past the structure and stabilize the sand fill between the Kuhio crib wall and the groin. With a crest elevation of +3.5 ft above mean sea level, and a toe elevation of -2.8 ft msl, the groin has been designed to the minimum size allowable that will still be an effective erosion control measure.
“This project is a much-needed erosion control measure with immediate impact to mitigate chronic beach erosion in Waikīkī. It is also an important first step towards more proactive and comprehensive beach management and maintenance in Waikīkī.” said Suzanne Case, DLNR Chair.
“The Waikīkī Beach Special Improvement District is excited to see this project get underway just in time for the Winter break, we are proud to be a partner in this important effort but also pleased to see the onset of a new era of proactive beach management plans and improvement projects get underway in Waikiki.” said Rick Egged, President of the Waikīkī Beach Special Improvement District Association (WBSIDA).
The $568,000 State project is supported through a public-private partnership with the Waikīkī Beach Special Improvement District, which is paying for 50% of the project through a special tax assessment from Waikīkī commercial properties. The City and County of Honolulu is also a project partner since the project falls within the Kuhio Beach Park boundaries and is providing access and staff support.
The project start date is Monday, November 4th, 2019 with a construction timeline estimated of 2-3 weeks for completion. The project consultant and engineering designer is Sea Engineering Inc and the contractor for construction is JS International, Inc.