On their first trip to Île-à-Vache (Cow Island) in Haiti nearly two years ago, Nat and Pam Benjamin fell in love with the 20-square-mile island and its people. About 12,000 islanders live a simple life of subsistence farming and fishing about seven miles off Haiti’s southwest coast — the same distance as that between the Vineyard and Cape Cod. Sailing from Vineyard Haven aboard his 50-foot schooner Charlotte in December 2014, Mr. Benjamin and his crew brought a cargo of donated clothing, sails, rigging and boatbuilding equipment as well as supplies for the local orphanage and school. Ms. Benjamin flew down after Christmas to join her husband and meet the islanders.

“They have no electricity, no running water, no cars,” Ms. Benjamin told the Gazette. “They’re living from their gardens and by fishing,” from boats with patchwork sails. “On the whole island there are no stores,” she continued. “People sell things out of their houses from time to time, but you can’t just go into town and get vegetables or toilet paper: You have to take a boat to Les Cayes, which is on the mainland.”

The Benjamins returned to the Haitian island by air in January 2016 with more donations, and deepened their friendships with the orphanage director and others in the Île-à-Vache community. Now, they’re working to aid the people of Île-à-Vache after Hurricane Matthew smashed through southwestern Haiti last week.

“This is the worst storm that has ever hit them,” said Ms. Benjamin, who keeps in contact with Île-à-Vache through an English-speaking islander and locally-based aid workers. “They were not expecting this at all.”

A report forwarded by Ms. Benjamin from the Irish non-governmental organization Haven, which works exclusively in Haiti, detailed Matthew’s toll on Île-à-Vache: nearly 1,500 houses damaged, flooded or flattened, 135 fishing boats lost, more than 3,000 lobster pots and fishing nets swept away.

Almost miraculously, no humans on Île-à-Vache died during the hurricane’s fury. But disease is a serious risk because the storm and flooding overwhelmed and contaminated the island’s cisterns and wells.

“With the threat of cholera they really need clean water,” Ms. Benjamin said. Île-à-Vache is also in urgent need of fresh food, since Haven reports more than 1,650 gardens destroyed and 820 livestock animals killed. The gardens at nearby port Les Cayes were also swept away by the hurricane, although Ms. Benjamin said there are vegetables to purchase on the eastern part of the mainland as soon as funds are available.

International donations have provided some of the islanders with packets of pasta, oil, flour, rice and beans, but “they really need to have this fresh water and food, because of the pollution from all the flooding,” said Ms. Benjamin. Before the hurricane she had been raising funds to start a music program for Île-à-Vache.

Now she’s seeking donations to help the islanders with their most basic needs: clean water and fresh food. With more than $4,000 donated so far, Ms. Benjamin is preparing to send money to Samuel Altema, an English-speaking Île-à-Vache resident who is assistant director of the community center there. While Mr. Altema said by email Wednesday that he is still looking for a good source of fresh vegetables, the islanders can immediately use disposable filters to decontaminate their drinking water, according to Canadian aid worker Bruce Leeming of Friends of Île-à-Vache.

Ms. Benjamin’s nonprofit art foundation, Sense of Wonder Creations, is accepting donations to its Haiti fund via PayPal at senseofwondercreations.org and by mail at P.O. Box 1558, Vineyard Haven, MA 02568. The tax identification number is 80-0024610, and Ms. Benjamin said her organization takes no administrative fees for helping the Île-à-Vache islanders.

“The money is going directly to them,” she said. “They’re beautiful people and human beings who don’t deserve what’s happening to them.”