UN treaty for water sharing states that any countries wishing to build dams etc in their country must speak with down flow countries, therefore before India does this, India must negotiate with Bangladesh, Though we know that's never worked out, however I'm confident that Modi can make things work. He's put forward the land boundary agreement, he's looked into the teesta deal, he's looked into help the North east of India etc, and all though discussion with BD. Also he's helped fight againt the commie Mamatama. Also it's kind of hypocritical of India saying that they're against the building of dam on the brahampurta because of no cooperation, when succesive indian govenments have done the same.
All in all, I'm for it, but their must be some cooperation between India and Bangladesh, we must know the SWOT of building dams too (Swot=strength, weakness, opportunaties and threats) Lie is Bangladesh going to benefit (and before indian say, oh it's going to mitigate floods, remember, bangladesh needs those revers and floods, it's what helps fertelize our crops etc.) Remeber this also, agriculture is one of the biggest sectors in Bangladesh, counting for 40 odd something percent of the GDP.