Issue 15.3: June/July 2012

Shifting Sands

Story by Dawn Southard

Photos by Matt Mallams  

 

A few hundred yards off Waikiki Beach, an old Healy Tibbitts dredger barge, HT 538, is anchored in a gap in the reef. She’s a big, slab-sided vessel, and it takes five anchors and a spider’s web of steel cable to keep her in place. A small tug is tied up alongside, its big prop ticking over slowly to help hold HT 538 steady. Even so, the ungainly World War II barge rolls fitfully in the five-foot swells.

 

Cranston Kamaka, superintendent of the barge, barely notices. Kamaka runs the dredging operation from the cab of the barge’s crane, never taking his eyes off of the suction dredge that’s suspended from the jib boom. It’s Kamaka’s job to keep the dredge buried in place on the ocean bottom. He’s been doing this job for more than twenty years, and he’s an expert at it; with each passing wave, his hands and feet tap rhythmically at the crane’s controls: hoist, swing; hoist, swing; hoist, swing.

 

Kamaka and his crew are working on an elaborate project to replenish Waikiki Beach by tapping an enormous reservoir of sand on the ocean floor just offshore. The plan is simple in concept—suck the sand up and pipe it ashore—but ambitious in execution. It involves a lot of tense engineering: assembling 2,700 feet of pipe and towing it out to sea, constructing an enormous catch basin on shore to hold the sand and then spreading all that sand along 1,700 feet of beach. Even more tensely, it involves mucking around with the most famous beach in the world.

 


 

“This beach,” says Sam Lemmo, gesturing toward Waikiki, “is almost completely manufactured.” As the administrator of coastal lands for the Department of Land and Natural Resources, Lemmo is the state’s point man for the current renewal. He sees the project as the key to preserving Waikiki Beach, but it’s only the latest chapter in the long engineering history of this fabled waterfront. For nearly a hundred years, landowners have studded the shoreline with sea walls, groins (stone jetties extending from the beach) and crib basins in a futile attempt to hold onto their little bit of sand. Between 1927 and 1930 alone, eleven groins were built along the beach. That temporary solution, though, is part of the ongoing problem at Waikiki.

 

Chip Fletcher, a coastal geologist at the University of Hawai‘i, points out that the name “Waikiki Beach” is misleading. That makes it sound like a single, contiguous entity, but the shoreline has in fact been divided into sections over the last century. Tara Owens, one of Fletcher’s grad students, has identified seven current compartments: Kaimana Beach, Queen’s Beach, Kapi‘olani Beach, Kuhio Beach, Royal Hawaiian Beach, Gray’s Beach and Fort DeRussy Beach. The names might conjure all kinds of romantic associations, but this segmentation lies at the root of Waikiki’s sand problems. To understand why, you have to imagine Waikiki as it once was, without its groins and sea walls.

 

Old drawings of Waikiki Beach depict a low, narrow dune backed by marshes and ponds—a kind of thin barrier island. This architecture represents the dynamic relationship between sand and waves. Without human intervention, beaches wax and wane with the seasons. They narrow and expand, move inshore and off, heap up in dunes and spread out in shoals. On a natural beach this ebb and flow is fluid and continuous.

 

“High waves tend to be seasonal or storm-related,” Fletcher explains. “The waves come in and erode the sand, and the sand will migrate off the beach.” Often this forms a sandbar, which makes the sea floor shallower, causing the waves to break farther offshore, which protects the beach. “Then when the high waves are done,” says Fletcher, “the low, fair-weather waves gradually migrate the sand back onto the beach, and the winds pick it up and rebuild the dunes. Beaches are built by waves; you cannot isolate a beach from waves and expect it to do very well.”

 

But of course, that’s precisely what all the groins and sea walls along Waikiki Beach have done. “Whatever natural processes that used to exist there have been interrupted,” Fletcher says. Groins are designed to reach out into the sea and interrupt the natural long-shore movement of the sand, but even as sand accretes on the upstream side of the groin, it erodes on the downstream side. So instead of a single long beach stretching from Kaimana to Fort DeRussy, we’re left with a scalloped coast of small, artificial beaches, each slowly starving its neighbor.

 

The groins, however, might not be the worst of the problem. During storms, when a natural beach erodes, large waves can reach up and take additional sand from the dunes. Fletcher likens this to a bank. “The beach is a sort of checking account, with lots of withdrawals and deposits. But when you have truly massive waves, you need a withdrawal from your savings account: the dune field.” From the very beginning, though, Waikiki’s hotels have been built atop the dunes. Like the groins, the hotels and their sea walls starve the beach of sand.

 

And there really wasn’t that much sand to begin with; the original barrier island at Waikiki was relatively anemic. Even more astonishing is how little sand there is offshore in Hawai‘i as a whole. There are some exceptions—there are pockets of deep sand at Waimea Bay and Kailua Bay, for example—but typically, most of the sand is sitting right there on the beach. That’s why the reservoir of sand off Waikiki is so valuable.

 

As Fletcher points out, much of the sand on Waikiki Beach isn’t from Waikiki at all. Over the years, the beach has been renewed countless times with imported sand. A fair amount of that sand, he says, is from Päpohaku, on the west side of Moloka‘i, and some might also have come from Maui. Most of the imported sand, though, was trucked in from other parts of O‘ahu. “Some came from Kahuku,” Fletcher says. “They mined the dunes there up until fifteen or twenty years ago. There was also a lot of sand mining in Waimea Bay in the 1940s, but we’re not sure if any of that went to Waikiki. Most of it went to make lime that they put on the cane fields as fertilizer. But if you go to the Los Angeles area, they have a stretch of beaches there called the Grand Strand. There’s a long bikeway that goes through Venice Beach, Marina Del Rey and Manhattan Beach, and apparently there’s a plaque there that says, ‘Sand from this beach was used to build Waikiki.’”

 


 

The current $2.3 million project, which aims to restore Waikiki Beach between the Kuhio swimming basin and the Royal Hawaiian groin to its 1985 widths (an average of thirty-seven feet, nearly twice its current average), isn’t the first attempt. Indeed, Lemmo points out, just five years ago the state had a similar renewal project on neighboring Kuhio Beach—a sort of dress rehearsal for the current effort. But there are a couple of important differences, Lemmo says. “On Kuhio Beach we only nourished the protected crib basins; now we’re nourishing open beach.” The crib basin at Kuhio Beach is basically the enclosed swimming area. “The other difference is the quantity of sand. At Kuhio we put down 10,000 cubic yards; this one is 24,000.” Further, the project isn’t going to just widen the beach; it’s going to raise it as well. “The elevation is going to be about six feet, so we’re going to inflate the beach both vertically and horizontally,” says Lemmo.

 

Although this project is dwarfed by some Mainland beach renewals, which sometimes exceed 200,000 cubic feet of sand, it’s still the largest in Hawai‘i’s history. That creates complications. Royal Hawaiian Beach is almost 1,700 feet long, and for much of that length, beachfront hotels block access. This is also one of the most heavily used stretches of Waikiki Beach, the epicenter of Hawai‘i’s tourism industry. Closing the entire beach for the duration of the renewal project would be a logistical nightmare, but without closure, says Lemmo, “It would be almost impossible to load the sand in trucks and move it down the beach.”

 

Healy Tibbitts proposed an alternative. Sand would be pumped ashore and piled high in the Kuhio crib basin to dewater. Then the dry sand would be spread, one 200-foot section of beach at a time, using a low-pressure blower. That way, Lemmo says, most of the beach could be kept open at any given time. The whole project was to be finished before May.

 

Things didn’t turn out that way. In the end the sand blowers didn’t work, and so sand had to be trucked up the beach the oldfashioned way. That meant closing Royal Hawaiian Beach to visitors every morning from 7 a.m. until noon— a “nightmare,” says Lemmo, but one that Hawai‘i tourism officials are convinced will be worth it.  

 


 

Not surprisingly, the quality of a beach is closely tied to the nature of its sand. Compared with the talcum-soft strand of Lanikai, Waikiki feels a bit gravelly. Except for the occasional black or green sand, most of Hawai‘i’s beaches are calcium carbonate. But not all carbonate beaches are alike. We tend to think of beaches like Waikiki as coral sand, which is produced by our offshore reefs, but Fletcher says that our sandy beaches aren’t predominately coral; they’re mostly composed of crushed-up hard algae. “There are two kinds of hard algae,” he explains. “There’s encrusting or coralline algae, and the other one is Halimeda, a green plant. When it dies its photosynthetic material goes away and a white sort of disk remains. These are the dominant components of most of our beaches.”

 

Fletcher and his graduate students have studied the composition of Hawai‘i’s sands closely, and what they’ve found gets right to the heart of Hawai‘i’s apparent poverty of sand. “Kailua sand,” says Fletcher, by way of example, “is 90 percent reefderived carbonate sand. It’s dominated by up to 50 percent coralline algae, which would be that encrusting algae. That’s followed by about 30 percent Halimeda.” The rest is made up of coral fragments, plankton, bits of mollusk shells and tiny amounts of lava. Much of the pulverization of this material is the action of fish and urchins, which points to a painstakingly slow rate of accumulation. “We radiocarbon-dated the sand on Kailua Beach,” Fletcher says, “and found that very little of it is modern. The youngest sand was about five hundred years old; most of it is two to four thousand years old.”

 

“Figuratively,” he adds, “we see the ‘sand factory’ as sort of adding a teacup of sand a year.” In other words, the sand that we have now is pretty much the same sand we’ve had for millennia. This is why it’s so important to husband the sands of Waikiki.

 

For Sam Lemmo, all this means that the renewal of Royal Hawaiian Beach is going to be just one episode in an ongoing drama. “The problem is long-term erosion,” he says. “On average we’ve lost about a foot of beach a year for thirty years.” Left unchecked, much of the beach would wash away entirely, much like the section in front of the Halekulani Hotel known as Gray’s Beach.  

 

To keep up with that pace of erosion, experts like Chip Fletcher will have to continue monitoring the flow of sand in Waikiki. The state and the hotels along the beach will have to continue to invest in replenishment, especially in light of rising sea level. Already, Starwood Hotels, the owner of the Moana Surfrider, plans to raise the level of its Diamond Head wing as part of new development. It’s probably too late to move the grand hotels off their dunes, though. And although it might help a bit to remove the groins, Fletcher says that the damage has been done. After all, some of the engineering mistakes in Waikiki are a century old. So to hold onto the beach we have now, every eight or ten years you’ll see someone like Cranston Kamaka mooring a barge out on the reef to dredge for sand.