Early one morning in 1990, conservationist Seub Nakhasathien shot himself dead in his office in the Huai Kha Khaeng Wildlife Sanctuary.
The untimely death of the renowned conservationist, who played a vital role in stopping the Nam Chon dam that would have endangered Kanchanaburi's Thungyai Naresuan Wildlife Sanctuary, was a shock to the country.
The loss of Seub appeared to trigger public awareness about environmental protection.
And after his death, the Seub Nakasathien Foundation was established and Huai Kha Khaeng became a World Heritage site.
But just four years after Seub's death, the Royal Irrigation Department began to conduct an environmental impact assessment (EIA) study for a dam in Mae Wong National Park in Nakhon Sawan, one of our most pristine forests, which serves as the Huai Kha Khaeng's buffer zone.
The dam proposal faced resistance from conservationists, who joined forces with the foundation to oppose it. The EIA studies were eventually rejected by the National Environmental Board and the project was shelved in 2002. But that was not the end of the matter.
The Yingluck Shinawatra government is now attempting to revive the Mae Wong dam project as part of its 350-billion-baht water management plan, presumably in response to the massive flood of 2011.
In its attempt to justify the proposal, the government claimed only 2% of the nearly 900 sq km of fertile forest in which it will be built would be affected. But conservationists have argued that this 2% is the heart of the Mae Wong National Park that serves as a habitat for tigers and other wildlife. They are also critical of the environment and health impact assessment (EHIA) study, conducted by the Irrigation Department.
The study bypassed a public hearing _ a public participation process is required under the constitution _ and failed to include important data about the forest's fertility. Suspicions were also raised by the change in the head of the experts committee, who believed the EHIA study employed underhand tactics to gain approval for the project.
However, Deputy Prime Minister Plodprasop Suraswadi has dismissed the conservationists' concern, insisting the government will complete the project in eight years. "I choose the lives and safety of Thai people. A forest can be constructed, wildlife bred. But if there is another flood, there won't be Thai people," he said this week.
On the opposition front lines is Sasin Chalermlarp, secretary-general of the Seub Nakasathien Foundation. He questioned the project's transparency _ or lack of it. In getting his message across to the public as well as the government, Mr Sasin, accompanied by a small group of fellow conservationists, embarked on a 388km-long march from Kamphaeng Phet to Bangkok on Sept 10.
While most of the mainstream media treated Mr Sasin's march as a non-event, the walk attracted huge attention in social media with thousands of "shares" and "likes" on Facebook and other channels.
Upon his arrival at the Bangkok Art and Cultural Centre on Sunday, Mr Sasin was given a warm welcome by several thousand people who share his environmental concerns and turned out to welcome the marchers to the city.
"No Dam" banners were everywhere and many participants wore white T-shirts emblazoned with the anti-dam logo.
The huge public turnout against the Mae Wong dam must have stunned the government which, I believe, has underestimated the people's power. Their message is loud and clear: "Listen to the people."
Foundation president Rataya Chantien said she fears the conservationists will not be able to stop the dam project this time.
"Khun Seub has been dead for 23 years. [If the Mae Wong dam is constructed], his actions will have been in vain. Do we need to sacrifice another life?" she said.
But the march's success on Sunday might well persuade the government to think again.
No one need sacrifice his life. The government has no choice but to listen to the people.
Paritta Wangkiat is a reporter covering the environment and social issues, Bangkok Post.