Conservation group sues over Chanthaburi reservoir plan
The Seub Nakhasathien Foundation has asked the Administrative Court to suspend use of the Khlong Wang Tanod reservoir EHIA
- The Seub Nakhasathien Foundation has filed a lawsuit against Thai state agencies over the Khlong Wang Tanod reservoir project in Chanthaburi.
- The lawsuit seeks to revoke the approval of the project's environmental and health impact assessment (EHIA), alleging it contains significant inaccuracies.
- The foundation argues the project will cause severe damage to ecosystems and wildlife habitats, particularly within the Khao Sip Ha Chan National Park.
- As part of the suit, the group is requesting a temporary court order to prevent the EHIA from being used to remove land from the national park for construction.
The Seub Nakhasathien Foundation has taken legal action against state agencies over the Khlong Wang Tanod reservoir project in Chanthaburi, asking the Central Administrative Court to revoke approvals for the project’s environmental and health impact assessment and temporarily block the report from being used to support the removal of national park land.
The lawsuit was filed at the Central Administrative Court on Chaeng Watthana Road at 10.30am on June 5, 2026, coinciding with World Environment Day.
The foundation’s secretary-general filed the case as an authorised representative.
The case names the National Environment Board, the expert committee responsible for reviewing environmental impact assessment reports for water resource development projects, and the Royal Irrigation Department.
At the heart of the lawsuit is the foundation’s challenge to the approval of the environmental and health impact assessment, or EHIA, for the reservoir project.
The foundation is also seeking temporary protection from the court to suspend the use of the approved report in any process to revoke land within Khao Sip Ha Chan National Park.
The foundation said it has opposed the Khlong Wang Tanod reservoir project since 2020 and has proposed reducing the project’s scale to avoid impacts on Khao Sip Ha Chan National Park, an important wildlife habitat.
It argues that a smaller project could still meet local water needs at an appropriate level.
The foundation said it had repeatedly challenged information contained in the EHIA report before relevant agencies.
Several conservation organisations and academic institutions also expressed opposition in 2021, while more than 10,000 people signed a Change.org petition calling for the report to be reviewed and for alternative water development options with lower impacts on natural resources, wildlife and the environment to be studied.
However, the foundation said the Royal Irrigation Department and related agencies had continued to move the project forward through legal procedures despite objections from several sectors over the accuracy and completeness of the EHIA.
The lawsuit centres on allegations that the project’s EHIA contains inaccuracies on key issues. The foundation argues that these alleged flaws could affect the assessment of damage to natural resources and the environment, while also making the proposed prevention and mitigation measures unrealistic or difficult to implement.
The foundation warned that if the project proceeds on the basis of the contested report, it could cause serious damage to ecosystems, biodiversity and wildlife habitat.
It also said the project could intensify human-wildlife conflict, particularly problems involving wild elephants whose habitat could be altered.
Three court requests
The foundation has submitted three main requests to the court.
First, it is asking the court to revoke the March 27, 2020 resolution of the expert committee reviewing environmental impact assessment reports for water resource development projects, as well as the June 21, 2021 resolution of the National Environment Board, both of which approved the EHIA for the project.
Second, it is asking the court to order the Royal Irrigation Department to suspend the use of the approved EHIA report in any process to revoke land within Khao Sip Ha Chan National Park for the project.
Third, it is seeking an order suspending use of the report in submissions to the Cabinet and other relevant agencies.
Protected forest at centre of dispute
The Khlong Wang Tanod reservoir project is located in Chanthaburi.
Its headworks and reservoir area cover a combined 11,982 rai, including 5,791 rai in Khun Song National Forest Reserve and 6,191 rai inside Khao Sip Ha Chan National Park.
Khao Sip Ha Chan National Park was declared Thailand’s 122nd national park on December 25, 2009.
It forms part of the Eastern Forest Complex and serves as an ecological corridor connecting Khao Ang Rue Nai Wildlife Sanctuary and Khao Soi Dao Wildlife Sanctuary.
Although the park covers only 73,729 rai and is one of the smaller national parks in the Eastern Forest Complex, it is considered important for wildlife movement, genetic exchange and the survival of large mammals, including wild elephants and gaur.
The case is now before the Central Administrative Court, which will decide both the foundation’s request for temporary protection and its petition to revoke the resolutions approving the EHIA for the Khlong Wang Tanod reservoir project.
