The Domes That Gave the Coast Back

The coast north of Carmen, on the island of Cebu, had been ugly for as long as anyone could remember. A quarry, opened in the years after the war, had stripped the mangrove fringe, compacted the slope, and left a raw shelf of degraded land running down to a sea that had, in the years of the quarry's operation, lost the fish that the mangrove had nursed. Maria, who is an environmental engineer, had spent fifteen years designing renewable energy and water systems for resorts on other islands — Palawan, Boracay, the coast of Vietnam — and had watched, in those years, the coastal degradation pattern repeat. She had come home, in her late thirties, because her grandmother's land — the degraded shelf above the quarry — had come to her, and because she was tired of building systems for buildings she had not chosen.

## The brownfield

The site was a brownfield. The soil was compacted. The mangrove was gone. The slope's natural drainage, which had fed the mangrove with the rainwater it needed, had been graded flat by the quarry's operators and now sheeted its runoff straight into the sea, carrying the sediment that had killed the coral below. An environmental engineer, walking the site for the first time, would have read it as a problem to be solved before any building could begin. Maria, walking it with us, read it that way too, and asked the question that defined the project.

"The resort has to heal the site," she said. "If it does not heal the site, I do not want to build it."

## What the dome does

The form we proposed was a cluster of domes — the great social dome at the highest point, the sleeping domes stepping down to the sea. The dome is not a stylistic choice. It is the most materially efficient way to enclose a tropical space — the minimum surface area for the maximum volume, which means the minimum solar exposure and the minimum material. The structure is bamboo — the giant tropical species, harvested from certified plantations on neighbouring islands, joined by Cebuano carpenters whose families have worked the material for generations. The sheathing is hempcrete — the hemp-lime composite, cast onto the bamboo frame in the great curved form. Hempcrete sequesters carbon. It regulates humidity. It insulates. It breathes. There is no concrete in the domes. There is no imported steel.

The bioclimatic logic of the dome is the reason the form was chosen, not its aesthetics. The great curve sheds the monsoon rain. The oculus at the crown vents the warm air. The hempcrete's mass holds the night's cool into the day. The deep terrace overhang shades the opening. The great dome has no mechanical cooling. In the Cebu climate, with the trade wind and the thermal mass, it does not need it.

## The regeneration

The mangrove was the first thing. We replanted it, in the first phase, with species native to the Cebu coast — the same species the quarry had stripped fifty years before. Three years in, the fringe is re-established. The juvenile fish are back. The coastline, which had been eroding, is holding. The slope, re-graded to its natural contour, drains the way it did before the quarry, and the runoff that reaches the sea is clear, not sediment-laden. The coral below, which had been smothered, is beginning to come back.

Maria told me, on the great dome's terrace one dawn, that the regeneration had been the part the engineers understood and the architects had not. "The building is the easy part," she said. "The building is geometry. The land is biology. Biology takes longer. But the land, if you give it what it needs, gives back more than you gave it. The building never does that. The building only takes."

## What the resort runs on

The resort operates off-grid. The photovoltaic plant, sited on the service canopy, sized to the load, provides the electricity. Solar thermal provides the hot water. The greywater runs through reed beds back to the slope's irrigation. The blackwater is processed in a sealed biodigester whose output fertilises the kitchen garden. Rainwater from the dome roofs is stored in stone cisterns beneath the terraces. In steady state, the resort produces no waste. The hempcrete domes, whose hemp absorbed more carbon than the lime in them emitted, make the construction itself carbon-negative. Over its life, the resort pulls more from the atmosphere than it releases.

This is the part Maria had been engineering for other people's resorts for fifteen years. The Cebu resort was the first time the engineering was her own, and the first time it was built into a building whose architecture had been designed to need the least of it.

## What Maria discovered

The resort opened with six domes. The reviews, in the way of tropical resorts, were favourable — the terraces, the sea, the temperature stability of the hempcrete, the quality of the silence. Maria does not read the reviews. She reads, instead, the quarterly mangrove report. Three years in, the fringe is a functioning ecosystem. Five years in, she expects, the coral below will be measurably recovered.

She told me, on the terrace, that the project had taught her the thing she had been missing in the fifteen years of engineering for other people. "I was always solving the building's problem," she said. "Take the building's energy, take its water, take its waste, and close the loops. I never asked whether the building should be there at all. This one — " she gestured at the domes, at the mangrove, at the sea — "this one earns its place. The land is better for it. That is the only standard I am interested in, now."

The best buildings are not the ones that take the least from the land. They are the ones that give back more than they took — and the dome, the mangrove, and the engineer who insisted on both are, finally, the same argument.