The majority of water that broke the riverbanks came from the hillsides around the city. This rough diagram shows how that rainwater could be channeled in gulley-sluices to river dams upstream. Locals are talking about eyesore like sluices but by using the natural shape of the hill large concrete sluices cut inward at an angle could ferry the water down to dams further upstream. Largely unseen until close up they'd preserve the natural aesthetic too. http://s30.postimg.org/z4s8jt9kx/img001.jpg