. >> woodruff: i'm going to interrupt one second and bring catharine dahl pino in. so just how much of this is man-made and how much of it is mother nature overwhelming what people can deal with? >> well, for the past several years there have been changes on the river, some starting in china with dams that they built through laos and on down. and thailand has become very recently sensitive to this. understanding that beyond their own national borders there are things that are happening. the simpson center here in washington has done some wonderful work on that. and recently thailand asked laos to suspend work on a dam that was being built by thai companies because it feared the im vool-- environmental impact. so there some awareness that there are things happening in terms of changing infrastructure. >> woodruff: so you are talking about a region wide set of issues rather than something within each country. >> well, also in thailand the past couple of decades there was severe logging. and in 1988 there were historic floods in southern thailand. and because of that t