Every dam is different...but if a dam has a small reservoir capacity (perhaps partly due to lack of maintenance - so what looks like water behind the dam is mos

Every dam is different...but if a dam has a small reservoir capacity (perhaps partly due to lack of maintenance - so what looks like water behind the dam is mostly accumulated silt), a narrow range of control (the water level is not much different between "flood gates fully closed" and "flood gates fully open", local-only manual controls (vs. pushing a button at National Flood Control HQ), and other issues - then it's actually of little use for those.