Conservationists have opposed a plan to build seven dams in Nakhon Nayok and Prachin Buri, saying the project will devastate 16,000 rai of land in the Dong Phaya Yen-Khao Yai forest area.
Ornyupa Sangkaman, secretary-general of Seub Nakhasathien Foundation, expressed grave concern that many trees in the forest would be lost if the dam projects proceed.
Many national parks are within the area that covers Nakhon Nayok and Prachin Buri, including Khao Yai, Thap Lan, Ta Phraya and Pang Sida national parks, as well as the Dong Yai Wildlife Sanctuary, which was listed as national heritage in 2005.
Ms Ornyupa questioned whether the government can be relied upon to manage water resources effectively and address tough environmental issues in an environmentally respectful manner.
Sophanat Kingpha, a member of the Sarika Tambon Administrative Organisation (TAO) and the Ban Khlong Maduea community leader, said each time there is a meeting regarding the environment impact assessment (EIA) with the Royal Irrigation Department, the consulting firm takes photos of villagers who oppose the project but make it look like the villagers support it.
Mr Sophanat alleged that certain figures cited in the EIA report were embellished, such as a claim that 75% of local residents favoured a dam in Klong Maduea, and only 5% were against it.
But he said the number of people in the survey included those from other areas unaffected by the planned dam construction. Among those who voted for the project stood to benefit from it, he said.
"It's not fair to us. We are in danger of losing our properties, our homes, our farmland, and our forests," he said.
When residents filed a complaint with the National Human Rights Commission, he said, they were called on to provide a multitude of evidence to support their petition.
Protected trees, like the golden jasmine tree, are among those in the threatened forest, Mr Sophanat said.
"The important thing is Klong Maduea watercourse does not have water all year long. So, where will the dam with an 80-metre-tall crest get water to fill it all year round from, water needed to push out salt water [intrusion]?" he said.
"I do not think the project will be worth the budget."
Also opposing the dam projects are Ratana Srivorakul from the Prachinburi Organic Farming Network, Thap Lan Friends Group coordinator Chandranon Chayaninsivakul and Bang Pakong River Basin Network coordinator Kan Tattiyakul.
They said the project would supply water to factories at the cost of a potential environmental disaster.