ScienceNews: Residents of Louisiana, take note: If engineers don’t divert sediment-rich waters from the Mississippi River to help replenish a sinking river delta, about 10 percent of your state will slip beneath the waves by the end of this century. However, even if the engineers do try to abate the subsidence, the Mississippi doesn’t carry enough sediment to offset more than a small fraction of that loss, a new analysis suggests. Over the past few centuries, about a quarter of the wetlands in the …