Although, hydropower projects in the country are the main driving force behind the country’s economy growth, its impact on environment, particularly on aquatic life, has always been a concern.
Constructing a fish ladder in the dams is one of the ways to mitigate its impact on aquatic life, especially to the fish population.
Currently of the many hydropower projects that have been constructed and are coming up, only two hydropower projects have adopted this measure. Kurichhu Hydropower Plant is one of them.
A fish ladder is built in order to allow the migration of fish from downstream to the dam reservoir. The fish ladder in Kurichhu is a pool and weir type, which is one of the oldest styles of fish ladders, and has a depth of two meters.
|
|
|---|
“It was easier with Kurichu because it is a lower dam. It is just 35 meters high. So in low height dams it is always possible to have fish ladders,” said Druk Green Power Corporation’s Managing Director, Dasho Chhewang Rinzin.
Dasho said they also have a similar project in Dagachhu. Dagachhu Hyrdopower also has a low head dam.
“But, other projects like Tala and Punatsangchhu I and II and Mangdechhu have high dams and it is quite difficult to design a fish ladder,” said the Managing Director.
Given the stringent environmental laws in the country, The Managing Director says, there is pressure to adopt such measure in other hydropower projects.
Dasho admits that not enough has been done to preserve the aquatic life. But, since fish ladders are no feasible in the upcoming hydropower projects, he said other measures would be adopted in the future.
“Normally, when the dams are high and fish are not able to migrate, you normally breed fingerlings and you transport up and downstream depending on the season they migrate. But that’s an evolving art. Of course, in the western countries, they have fully evolved it. Fingerlings are bred in one place and they are moved to another place. But in Bhutan, we are now thinking of starting it in Punatsangchhu I and II dams.”
Chhewang Rinzin said it is important for Bhutan to see if there is a need to build new dams or if it should remain environmentally controlled society.
“As I see today, most of the revenues for Bhutan come from the Hydropower sector and we have plans into long term future using revenues generated by our hydropower sector that we are expecting to get by building more hydropower projects.
Dasho said this is how the whole process has been built. “I think the whole thought of at one time being self-reliant and being reasonably rich and a well off country, has been all planned along by using the hydropower resources that we have. But of course, on the other side, as we are saying, the environmental and social issues are there.”
The Kurichhu Dam fish ladder remains closed from November till February every year as studies suggests that fish do not migrate during those months.
