People Called Them Crazy for Rebuilding Hawaii’s 800-Year-Old Rock Wall — Then 2,000 Showed Up.

Beaches, palm trees, paradise. But this island imports between 85% and 90% of its food. If ships stopped arriving tomorrow, there'd be a serious problem within days. About 800 years ago, and I say about because nobody knows the exact date, Hawaiians built something that solved that problem. A wall over 2 kilometers long, made of basalt and coral stacked by hand, stone by stone, With no mortar, no cement, not a single machine. They built it on top of a reef, encircling a piece of the bay. What for? To trap fish. And it worked for centuries. Until it didn't. This is the story of how 2,000 people showed up on a Saturday in December to finish rebuilding it. Of the woman who dedicated her entire life to making that happen. And of why, even now that the wall is complete, the real problem still isn't solved. It's called a loko iʻa, a fish pond. But it's not what you're picturing. Not a garden pond, not a giant fish tank. Think of a ranch, but in the water. They built a massive wall on the reef, along the coast. This wall has seven gates, called makaha, with wooden grates. Four face the ocean and let salt water in. Three face the stream and let fresh water in. The gaps between the grates are wide enough for baby fish, the pua, to swim in from the sea. They enter, eat, grow. But once they're adults, they no longer fit through the grates. And nobody feeds them. When freshwater mixes with saltwater, phytoplankton and algae appear naturally. Herbivorous fish feed on that, just like cattle grazing a field that grows on its own. Kavika Winter, director of the Estuarine Reserve, has a word for this – eco-mimicry. Instead of forcing the environment the way industrial aquaculture does, they mimic and amplify it. The two main species are amaama and awa. But inside, there also live moray eels, shrimp, and crabs. The Samoan crab, which is invasive, gets harvested and sold at $10 a pound. Even the problems generate something. One researcher measured that a single makaha can exchange a million gallons of water per day. has seven a million each but that's just the concept the actual pond has a name and address and dimensions it sits in Kaneohe Bay on Oahu nobody knows who commissioned it according to the organization that maintains it it is unknown who ordered the construction it probably took hundreds maybe thousands of people passing and stacking rock and coral over two or three years the result Basalt – 88 acres of brackish water, roughly 36 hectares, barely a meter deep, enclosed by a wall over 7,000 feet long, something like 20 football fields laid end to end. Two parallel walls of basalt separated by about 4 meters, with coral fill between them. Just stones holding each other up by their own weight. The word kuapa, the name of the wall, comes from kuwa, back, spine. What makes He'ea special is that it's the only Hawaiian fishpond whose wall forms a complete circle. Most kuapa run in a straight line or a semicircle from one point of the coast to another. This one wraps around the entire inner bay. It's possibly the longest wall in the archipelago. But the wall is just one piece. To understand why it worked, you have to go up the mountain. Hawaiians divided the land into strips running from the mountain top down to the sea, the Ahupuaʻa. Up high, rainwater flows down through the streams. Along the way, it irrigates taro terraces and carries sediment and nutrients. Those nutrients reach the pond, feed the plankton, algae grow, fish eat. A local administrator, the Konohiki, controlled fishing rights and directed construction. The historical yield was between 400 and 600 pounds of fish per acre per year. For He'ea, that meant at some point around 44,000 pounds annually, enough to help feed about 6,000 people. It's not a verified number. It's an estimate that varies by source, but it gives a sense of the scale. Ki'ile Kavelo, the woman who's spent over 20 years restoring this pond, puts it this way. of the fish pond is a direct reflection of the health of the entire system. Remember that line, because what comes next is exactly what happens when the system breaks. Before European contact, researchers estimate there were about 488 fish ponds across all of Hawaii. Together, they produced around 2 million pounds of fish per year. In the 1901 survey, 360 were counted, but only 99 were still active. Those 99 yielded about 680,000 pounds annually, 486,000 of amaama and 194,000 of awa. In Kaneohe Bay, where He'ea sits, of 30 walled ponds, only 12 remain today. Nine were filled in between 1946 and 1948 to build houses. The causes piled up. Epidemics of foreign diseases dismantled the communities that maintained the ponds. After the Great Mahele of 1848, much of the land passed to foreigners and corporations. Streams were diverted for sugarcane plantations. Cattle degraded the watersheds. The case that best illustrates what was lost is another pond on the same island, Keahupua o Mauna Lua. It was the largest on Oahu, 523 acres. In 1961, Kaiser Etna leased it from the Bishop Estate and turned it into the residential marina of Hawaii Kai. Today, families live where fish once swam. And the Bishop Estate, now Kamehameha Schools, is the same owner that today supports He'ea's restoration. He'ea was spared from being filled in not because someone protected it, but because after 1965, it was simply abandoned. And that wasn't exactly lucky, because what happened to it was worse. A slow death. At He'ea, the destruction wasn't an event. It was slow. From 1880 to 1910, the wall was still well-maintained. Taro, sugarcane, banana, pineapple, and rice were cultivated around it. Then the blows came, one on top of another. In 1902, red mangrove was planted for the first time in Hawaii, on Molokai. By 1922, it had been brought to He'eia to slow erosion. The mangrove didn't slow erosion, it devoured the wall. In 1927, stream pressure broke a section of the wall. Nobody repaired it. Meanwhile, in the bay, the U.S. Navy dredged over 15 million cubic yards of reef to build the Mokapu base. Between 1951 and 1979, sewage was dumped into the bay. Up to 8 million gallons per day in the 60s. Coral coverage dropped 70%. But none of that killed the pond. What killed it happened in 1940, miles away, up the mountain. The Haiku Tunnel was dug to drain the mountain water dikes and irrigate sugarcane. Federal gauges recorded what happened. He'eia Stream lost 1.4 million gallons per day. The tunnel severed the Ahupua'a connection. It took away half the pond's essential ingredient, fresh water. Today, that water supplies homes on the windward side, the Marine Corps base, the largest water consumer on Oahu, and four golf courses. Together, they consume over 1.9 million gallons daily. And not far from the pond, in the same watershed, the organization Kakuo Oivi manages some 400 acres of land. How many can they cultivate with taro? 15. If they had water, they could cultivate 150 more. There's no shortage of water in the mountain. The shortage is in the stream. On May 2nd, 1965, a flood tore open a breach over 60 meters wide on the seaward side. The pond was open to the ocean. And a pond open to the ocean is just... ocean. The mangrove covered everything. For 25 years, He'eia was a forgotten swamp. Cavello describes it. You couldn't see the horizon. It was a wall of mangroves surrounding the entire pond. So now you've got a destroyed wall, a dry stream, a mangrove swamp, and zero people interested. Who looks at that and says, I'll fix it? Between 1988 and 1990, a tenant named Brooks patched the breach provisionally and raised Amaama, Moi, Tilapia, and Ogo. It was the first real attempt to do something with the pond in decades. In 2000, Brooks partnered with the University of Hawaii to teach the first Malama Loko'ia class, fishpond management. From that class came a group of seven young Hawaiians who looked at He'eia and saw something no one else did. In 2001, they founded Paepae o He'eia, the foundation of He'eia. Coelho explained why. We saw a void, a lack of community involvement. Their plan was to rebuild the kuapa. The problem? Nobody alive knew how. The technique, uhau humu pohaku, Hawaiian dry stone masonry, wasn't taught at any university. There was no manual. People thought we were crazy, Coelho said. So they applied a Hawaiian principle, makahana ka ike, you learn by doing. For several years they worked for free, alongside their regular jobs. What they did have were the niho, the foundation stones placed by the original builders 800 years ago. The team followed that layout like a map. Kotubete put it this way. The wall was designed by our kupuna, who left this treasure for us to maintain. Seven people with no manual following stones from eight centuries ago. And they started cutting mangrove. They started with handsaws and pruning shears, then moved to chainsaws. In 2019, they removed a mangrove island over 160 feet in diameter and 70 feet tall that had formed from the debris of the 1965 flood. Water quality improved dramatically. Coelho explained it more directly. Removing the mangrove increases oxygen levels almost immediately. By 2014, they had cleared over 3,000 feet of wall. Today, more than and 60 loko iʻa and waiopai sites across various islands are in some stage of restoration. Before 2015, restoring a fishpond required meeting 17 federal, state, and county regulations, and permits took decades. Since the state streamlined the process with the Hoala Loko Ia permit, 23 have been approved across six islands. He'eia paved the way for the rest. And then came the moment they'd been waiting for over a decade. closing the largest breach. In 2014, they launched the Panika Puka campaign. Close the gap. 80 feet of destroyed wall. They raised $100,000. On December 12, 2015, they called for volunteers. They expected 1,000. 2,000 came. A study published in Sustainability in 2019 confirmed that repair changed the pond's water balance. Before the closure, during spring tides, water flowed in and out uncontrolled. After, the pond worked as designed again. But there were still 300 feet left, and they had to wait 10 more years. On December 13, 2025, the final closure was set. Mo'okuapa. People parked at King Intermediate School. School buses took them to the pond. Organizers asked for five-gallon buckets with handles. Kamehameha schools announced that 160 tons of coral would be moved. The method was the same one the kupuna used 800 years before, hali-hali. People form lines and pass buckets of coral hand-to-hand from the piles to their place in the wall. The rallying call was, Hulikalima ilalo, turn your hands downward to work. Nearly 2,000 volunteers came from all the islands, and even from outside the Pacific. The lead mason was Keahi Piohia. That day, 380 feet of wall were built. 380 long, 14 wide, 4 high. Pi'iohia This historic event allowed us to stand in the footsteps of our ancestors, as they did 800 years ago. There were traditional chants, mele and oli. The lei the volunteers brought were enough to circle the pond three times. A lunch was served made entirely from He'eia products. Fish from the pond, taro, cassava, and ulu. An elder in the community said he never thought he'd live to see this. The He'eia Wall, the only complete circular kuapa in Hawaii, was finished. But remember the freshwater that the tunnel took in 1940? It never came back. The National Estuarine Research Reserve put it plainly. Although the restoration may be technically complete, the work is far from over. There are still invasive algae, invasive jellyfish, predatory fish eating the species the pond needs. But above all, the water from the 1940 tunnel never came back. The pond's salinity today sits between 27 and 32 parts per thousand, when the ideal would be between 18 and 23. Coelho How are we even going to come close to what our ancestors cultivated if we only have half the freshwater? In 2021, the Commission on Water Resource Management determined that stream flow needed to be restored, and the diversion was cut in half, to about 300,000 gallons per day. But that didn't translate into more water for the stream. According to a USGS report, ceasing extraction from the Haiku well would increase the stream's base flow by just 26% of the volume no longer pumped. Ceasing extraction from the tunnel would increase it by 20%. The preferred option would cost $7.3 million and take 18 to 21 months, but it depends on a seepage study that's running behind schedule. The Honolulu Board of Water Supplies position. Full restoration to what it was before contact, or before the tunnel, is not possible. In Hawaii, water is a public trust resource. The state must balance paying users with resource protection and indigenous rights. It's not a simple question. And while that fight plays out, science is proving something that makes the decision even harder. A study published in Ecosphere in 2024 modeled Kaneohe Bay and found that a restored fish pond produces surplus fish that disperse into the bay. The pond functions as a nursery for the surrounding ecosystem. The authors say it's the first formal demonstration of that idea in the academic literature, although Hawaiian practitioners have known it for generations. A second study, published in NPJ Ocean Sustainability in 2025, found that under global warming scenarios, fish in the pond decline less than those in the bay, thanks to the cooling effect of freshwater. But there's a less optimistic finding. A 12-year data series published in PLOS One recorded two massive fish kills in the pond when trade winds weakened for weeks and water temperature rose 2 to 3 degrees. level rise is also a real concern the 2022 state report projects three to four feet of rise by 2100 as a mid-range scenario and Kotubete already warns that during extreme tides waves wash over the top of the wall so the pond needs more fresh water to survive warming but that same fresh water is what someone else is using and meanwhile how much does it actually produce Cavello has no illusions I don't think we're going to feed 6,000 people. Her immediate goal is to feed the volunteers. During the pandemic, they managed it. Meals made 100% from pond products. But there's no public figure for annual production. All of Hawaii's aquaculture produces about 20,000 pounds per year, less than 1% of the 70 million pounds of seafood consumed statewide. Paepae Ohe'ea operates on a budget of around 1.1 million dollars a year, of which 73% to 96% comes from donations. The permanent staff is eight people plus summer interns. Cavello earns about $93,000 a year. With those numbers, the food the pond can produce will never pay for the budget. But that's not what the pond is. The pond is a classroom, a laboratory, a monument and a source of protein all at once over 150,000 volunteers and students have come through in 25 years every second and fourth Saturday of the month anyone can show up but to work not to watch and between April and September there are family fishing days the la holo holo assigned by lottery because demand exceeds capacity they asked Cavello if all of this was just nostalgia it's not nostalgia it's learning from our ancestors ingenuity to face today's crises someone asked her if she was done everyone wants you to be finished but this has no end 2,000 people showed up on a Saturday to pass coral hand to hand nobody paid them nobody made them if 2,000 people do that what does it say about what we're missing the wall is complete the system still isn't. But He'ea isn't the only place where someone looked at a broken ecosystem and decided to fix it with rocks and patience. In New Mexico, a biologist named Bill Zedike did something similar with streams that were dying, not from lack of water, but because they were choking on sediment. What he pulled off with a few well-placed rocks and how many native trout came back is the video waiting at the end of this one. If you want more stories where the fix was a pile of rock and the wait was longer than anyone hoped? Subscribe!