Cedar Rapids Gazette: Mississippi River water quality has worsened in the last five years, spurred by agricultural runoff from Midwest states including Iowa, according to a new report from the America’s Watershed Initiative. The group gave the Mississippi River watershed a C-, up slightly from a D+ in 2015, when looking at four metrics: water quality and ecosystems, flood control and risk management; transportation; and water supply. But when focusing just on water quality, the river into which waters from 31 states flow and that makes up Iowa’s eastern border got a D. In Iowa, the amount of nitrogen flowing into the Mississippi River has doubled in the past 20 years, according to the report, which uses data from the Iowa Department of Natural Resources’ ambient stream monitoring.