Benchmark indicates spot to measure beach erosion

Question: I was walking around Kapiolani Park recently and saw a monument in the sidewalk that reads: “War Department Corps of Engineers U.S. Army/Traverse Station Honolulu District/Survey Position/Beach Erosion No. B Year /Lat. N. Waikiki/$250 Fine or Imprisonment for Disturbing This Mark.” It’s located mauka of the Dillingham Fountain on the makai side of Kapiolani Park, as you walk towards Waikiki. I was just wondering about the history of this kind of monument. Do you have any information?

Answer: It’s a vintage survey benchmark placed prior to 1949, the year the War Department became the Department of Defense, said Joseph Bonfiglio, chief of public affairs for the U.S. Army Corps of Engineers in Honolulu.

That particular benchmark “was placed in order to permanently mark a stable elevation point in order to scientifically measure beach erosion,” he explained. “It would be impossible to know how far a beach eroded without a permanent marker to measure it.”

Bonfiglio said such survey benchmarks also can be used to measure sea level changes and other vertical elevations.

Many of these benchmarks were installed around the state, not only by the Army Corps of Engineers, but also by the National Geodetic Survey and the U.S. Geological Survey, he said.

Bonfiglio explained that the term “benchmark” originates from chiseled horizontal marks that surveyors used to make in stone structures, into which an angle iron could be placed to form a “bench” for a leveling rod, ensuring that the rod could be accurately repositioned in the same place in the future.

These marks were usually indicated with a chiseled arrow below a horizontal line, he said.

“The term is applied to any item used to mark a scientifically verifiable stable point used as a horizontal and vertical (elevation) reference,” he said. “Frequently, bronze or aluminum disks are set in stone or concrete, or on rods driven deeply into the earth to provide this point.”

The Corps of Engineers uses benchmarks to assess its projects and assist itself and its partners in the state with important scientific survey information to protect the state’s valuable natural resources, Bonfiglio said.

“The Corps is totally committed to protecting the beautiful environment here in Hawaii.”

Time Change

The starting time for the first Wahiawa War Memorial ceremony on July 26 at the Wahiawa District Park Swimming Pool has been changed to 10 a.m. from 1 p.m.

Organizers are continuing to seek relatives of the 21 soldiers from Wahiawa killed in action during World War II whose names are memorialized on a plaque at the pool. (See bit.ly/1ehBNAg.)

Anyone related to those soldiers or who may have information is asked to contact Rene Mansho at 291-6151 or email renemansho@hawaii.rr.com.

Mahalo

To an ambulance driver and police officers who came to my aid last month, when a tire flew off my car as I was driving on the H-1 freeway toward Kahala. I pulled to the left shoulder lane and before I could even get out of my car to check the damage, an ambulance pulled in back of me and the driver got out and gave me an assessment. He then said it would be safer if I went over to the right shoulder, and he and his partner used their vehicle to stop traffic and guide me over. He then called police, who responded in a matter of minutes. Officer Okumoto and his partner stayed with me until I could secure roadside assistance. Officer Okumoto then took me to Kahala Mall to wait for the tow truck, saying it was not safe to wait on the shoulder. After this unnerving experience I have a newfound respect for first responders. They gave me reassurance and support in a frightening situation. Thanks very much to all of you! — Grateful Driver

Write to “Kokua Line” at Honolulu Star-Advertiser, 7 Waterfront Plaza, Suite 210, 500 Ala Moana Blvd., Honolulu 96813; call 529-4773; fax 529-4750; or email kokualine@staradvertiser.com.