When I hike to the summit of Diamond Head I often look back into the crater and wish that the Hawaii National Guard would demolish the three ugly, Cold War-era buildings cluttering the crater floor.

Diamond Head is the most famous volcanic crater of its kind in the world.  It should look as natural as possible, not they way it appears today  — an industrial yard dotted with chain-link fences and outdated military buildings.

It is uplifting to report this change is about to happen. With little fanfare, the Hawaii Department of Defense began preliminary work on August 21 to take down two of the three buildings in the center of the crater.  The structures are known as Building 301 and 304.

Air National Guard Public Affairs Officer, Lt. Col. Charles Anthony stands in Kapahulu Tunnel on the mauka side of Diamond Head also known as 'Mule Tunnel'.
Lt. Col. Charles Anthony of the Hawaii Air National Guard stands in Kapahulu Tunnel, known as the “Mule Tunnel.” The tunnel will become a bike and foot path into Diamond Head. Cory Lum/Civil Beat

Tom Moore, a daily hiker at Diamond Head, called it “fantastic news.”

Moore , an adjunct professor at Kapiolani Community College, says “It will make the crater floor more natural.  It may take a while but in the long run, it’s worth it.”

The third building, known at 303, is to be removed eventually, but not now because it is a newly renovated office facility for the Hawaii Emergency Management Agency (Civil Defense).

The demolition and cleanup work is funded with a $1.8 million federal appropriation.

This represents the first time the military will give up any of its buildings inside Diamond Head.

The only other agency to demolish its buildings and move out was the Federal Aviation Administration, which transferred its Diamond Head operations in 2001 to a building at what is now Joint Base Pearl Harbor-Hickam.

The ground under Buildings 301 and 304 in Diamond Head will undergo an environmental clean up and be planted with grass before it’s turned over to the parks division of Hawaii Department of Land and Natural Resources by June 2018.

For now, the newly available open space will be used for an interim food concession lunch wagon operation, a gift shop and additional parking, according to parks officials. A permanent use for the area will be determined later.

Demolishing the two buildings is just the beginning, according to the defense department. It also intends transfer for park use a key historic structure called the Kapahulu Tunnel or Mule Tunnel. The tunnel on the north side of the crater has been largely off-limits to civilians for more than 100 years.

12-inch mortar structures built in 1910 along the mauka side of Diamond Head.
Battery Harlow, with its installations for 12-inch mortar shells, was built in 1910. It will become an interpretive center to highlight the history of U.S coastal defense networks. Cory Lum/Civil Beat

Col. Neal Mitsuyoshi,  the State DODʻs chief engineering officer, says the department also will eventually also turn over a pre-World War II coastal artillery installation known as Battery Harlow.

Diamond Head preservationists have been calling for the land transfers for the last 40 years.

“This is definitely a first giant step to give land back to the public. We have been hoping for this for decades,” says Michelle Spalding Matson.

Matson is a member of the Diamond Head Citizensʻ Advisory Committee, formed by state lawmakers in 1977 to create a master plan for the Diamond Head State Monument .

The master plan, completed in 1979, urged the military to remove its structures as soon as it could find the money and a place to relocate them.

Diamond Head Crater is co-managed by the state Department of Defense and the Department of Land and Natural Resources.

Wording in the Diamond Head master plan makes it clear that  “The appearance of the crater floor should change from one of a military installation to a park-like or semi wilderness character.”

The master plan calls the military’s buildings on the crater floor “block-like concrete structures with no distinguishing architectural value.”

Planner Vincent Shigekuni calls the upcoming demolition of Buildings 301 and 304, “huge.”

Shigekuni and Frank Brandt of PBR Hawaii have just started work on a $35,000 state contract to update sections of the Diamond Head Master Plan to better preserve and protect the state monument.

“The open space created by removing two buildings will be a huge help,” he said.

I am most excited by the planned transfer of the Kapahulu, or “Mule Tunnel.”  When I was writing a book on Diamond Head I was allowed to investigate many of the 20 off-limits tunnels drilled into the crater.  Kapahulu Tunnel became one of my favorites.

Earlier this month, I got a chance to tour it again with a group from the Historic Hawaii Foundation.

Historic Hawaii Foundation “Unseen Diamond Head” tour participants going into Kapahulu Tunnel. Denby Fawcett/Civil Beat


The Kapahulu Tunnel was excavated through the crater’s north wall in 1908.  At that time, it was the only way to get into Diamond Head.  Visitors to the crater today enter through the Kahala Tunnel, which was was not built until 1943.

In the Kapahulu Tunnel’s heyday, mules pulled railroad cars filled with construction materials on narrow-gage railroad tracks through the tunnel and into the crater.

The building materials were then hauled up the side of the crater to build the fire control station that hikers visit at the summit today. It is a bunker-like structure once used by soldiers for observing and targeting enemy ships.

What makes the Mule Tunnel particularly fascinating is its two sub-tunnels dug into its west wall.  The rooms have electric lighting so a person could live and work there during a military or natural disaster crisis.

When the tunnel is eventually opened it will be used as a pedestrian and bicycle entrance into the crater, according to the parks division.

In an email, state parks officials Curt Cottrell, Alan Carpenter and Yara Lamadrid-Rose wrote: “Significantly, it should reduce the congestion in the Kahala Tunnel by giving pedestrians and bikers a safer alternative into the crater.”

Currently, pedestrians in the Kahala Tunnel must sometimes squeeze dangerously on a narrow path to avoid getting hit by cars, buses and trolleys going through the tunnel on a narrow, two-lane road.

The Kapahulu Tunnel also will give visitors walking or biking to Diamond Head a shorter route into the crater.

“Tourists walking up from Waikiki will get a short cut and a chance to see more history, more drama, more beauty. And thatʻs a winner,” said hiker Tom Moore.

Battery Harlow, with its installations for 12-inch mortar shells, was built in 1910. Preservationists hope it will become an interpretive center highlighting the history of U.S coastal defense networks.

Battery Harlow is the first fortification of any kind built by the U.S. for its coastal defense system to protect Hawaii and the West Coast from attack by ship.  Its eight 12-inch mortars could fire out as far as far as Pearl Harbor.

It is one of the most intact installations of its kind still left in the United States and clearly underutilized as an important historic artifact.

A historic photo of a test firing at Battery Harlow in Diamond Head. Courtesy of U.S. Army Museum of Hawaii

The DOD currently uses Battery Harlowʻs three bunkers for storage. And it has occasionally rented it for filming, including episodes of Lost and Hawaii Five-O.  Most recently it was used as a setting in the Imax movie “The Inhumans.”

Even with the changes coming, it will be a long time before Diamond Head is completely demilitarized.

Hawaii National Guard spokesman Lt. Col. Chuck Anthony says the goal is to return as much military property as possible to the Diamond Head State Monument Park by 2029  — the 50th anniversary of the completion of the citizensʻ Master Plan.

State DOD says in the meantime, it needs to keep Battery Birkhimer, the longtime headquarters of Hawaii Emergency Management Agency (Civil Defense).

And it says it also needs to retain Battery 407, the two quarter-mile-long tunnels cut from the craterʻs interior wall to the southern, ocean side of the crater. The twin tunnels house the National Guard’s emergency operating center.

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