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Hydropower developers learn scientific evaluation of EFlow

National Environment Commission Secretariat (NECS) provided training to hydropower developers to determine environmental flows (EFlow) of the rivers.

EFlow is the necessary quantity, timing, and quality of water flow required to sustain freshwater and estuarine ecosystems, human livelihoods and well-being dependent on these ecosystems.

As part of the project funded by Austrian Development Agency (ADA), NECS has trained individuals in the secretariat to conduct scientific evaluation of the EFlow of a river.

NECS’s environmental officer, Phuntsho Wangdi, said the project focused on EFlow evaluation on hydropower projects. “In hydropower projects there are about 5km to 15km length of dewatered areas. This is the place where EFlow is studied to determine the survival of the aquatic ecosystem.”

NECS has also bought field equipment and software to determine EFlow and has conducted EFlow on pilot sites at Wangchhu, Punatsangchhu, Parochhu, and Phochhu and has developed a draft guideline on EFlow under the project.

Phuntsho Wangdi said that the EFlow guideline contains information on collection of data, modeling, and analysis of field data. The guideline is yet to be implemented. “The guideline will be submitted to the commission for endorsement,” Phuntsho Wangdi said.

As part of the second phase of the project, NECS formed a taskforce with members from hydropower developers in April this year. About 20 members of the taskforce were trained in using the field equipment and in processing data. Following discussion with the taskforce, Mangdechhu site has been selected to study the EFlow with the taskforce members. “Until today EFlow study was vague and it wasn’t done scientifically. Detailed work with the new equipment is the first of its kind and there are not many who know this so we plan to teach them,” Phuntsho Wangdi said.

ADA supported the second phase of the project with €300,000.

The National Environment Protection Act of Bhutan 2007 states that reasonable amount of water for environmental flows to protect the fresh water biodiversity and maintain ecosystem functions should be ensured.

Phuntsho Wangdi said that Water Act of Bhutan 2011 also states that the commission shall in collaboration with competent authorities set minimum EFlow of water courses required to support and conserve the riverine habitats and its flora and fauna.

He added that until today EFlow was conducted roughly and didn’t have detailed information. “With the water regulation, if you don’t do a scientific EFlow assessment, then that will entail regulatory body such as NEC to make you let 30 percent of water to be kept at the dewatered area. Thirty percent water is too much and with the fish diversity it differs. It might not need water of that amount.”

The project began in October 2014 and will end on December 31, 2018.

Phurpa Lhamo

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