Everyone in that region will benefit from infrastructure investment, in the form of a boom in agricultural output and energy. Even neighbouring countries will get a more regular flow of water, preventing drought in the summer and floods in the winter months. It is daft to claim that building a dam would lead to war. Even though there may be some interruptions during the filling phase, after filling the reservoir Iraq will get the same water as usual.
Opposing investment in Eastern Turkey is tantamount to defending an archaic economic and social structure. We Turks feel we have an obligation to bring that backward part of our country into the 21st century. Environmental and archaeological concerns should of course be met. But that requires working hand in hand, not opposing the whole scheme.