The 49-year-old is one of hundreds of residents opposed to a new artificial lake that would feed the vital interoceanic waterway at the center of diplomatic tensions with the United States.

"I feel sick about this threat we're facing," said Martinez, who shares her wooden house with a metal roof with her husband and five of her 13 children in Boca de Uracillo.

"We don't know where we're going to go," she told AFP.

Martinez's entire family was born in the small village surrounded by lush mountains, whose residents earn a living growing crops including cassava and corn and raising animals.

The community says it is determined to prevent its homes being sacrificed to help the world's multi-billion dollar global shipping industry.

"We have to fight to the end," said 44-year-old resident Yturbide Sanchez.

Last week, hundreds of flag-waving villagers in motorized canoes navigated the Indio River to protest the planned dam, which would force thousands of families to relocate.

"We don't want them to take away the river water -- we need it," 48-year-old farmer Ariel Troya told AFP.

"If the project goes ahead, it will take away our entire future," Troya added.

- 'The future' -

The Panama Canal Authority (ACP), the autonomous public entity that operates the waterway, decided to build the reservoir to cope with severe droughts like the one seen in 2023, which forced a drastic reduction in ship traffic.

The century-old shortcut between the Atlantic and Pacific oceans relies on once-abundant rainwater stored in two artificial lakes that also supply drinking water.

Used mainly by customers from the United States, China and Japan, the canal has a system of locks to raise and lower ships and releases millions of liters of fresh water for each vessel that passes.

The planned new reservoir covering around 4,600 hectares (11,400 acres) would supply water through a nine-kilometer (5.6-mile) tunnel to one of the existing lakes.

The project "meets a need identified a long time ago: it's the water of the future," Karina Vergara, an environmental and social manager at the ACP, told AFP.

Work is expected to begin in 2027 and be completed by 2032, with an investment of approximately $1.6 billion.

Of that, $400 million is earmarked to compensate and relocate around 2,500 people from several villages.

"We have a firm commitment to dialogue and reaching agreements" with those affected, Vergara said.

If the reservoir isn't built, "we'll regret it in 15 years," she said.

- 'Give our lives' -

Civil society groups warn that in total around 12,000 people could be affected by the project -- which has the backing of President Jose Raul Mulino -- since it would affect the entire Indio River basin.

The 80-kilometer-long Panama Canal handles six percent of global maritime trade and is the engine of the Panamanian economy.

It is also at the center of a diplomatic row due to US President Donald Trump's repeated threats to "take back" the waterway -- which was handed over to Panama in 1999 -- from alleged Chinese control.

In the village of Limon, about 15 minutes from Boca de Uracillo by motorized canoe, residents also refuse to abandon their homes.

"We're not going to leave. They'll have to remove us by force," said Maricel Sanchez, a 25-year-old university student.

Villagers are relying on their lands to see them through retirement, farmer Olegario Cedeno said in the house where he lives with his wife and three children, surrounded by chickens, hens and parrots.

"We will give our lives in this fight."