Larry Weber, director of IIHR—Hydroscience and Engineering, says this winter has been unique, marked by early heavy snowfall and cold temperatures followed by a warm stretch. This has led to unseasonably high nitrate concentrations in waterways across the state.

Articles:

• Lack of frost in the ground leads to higher nitrate levels in Iowa waterways | Radio Iowa
• Warm weather, lack of frost partly why there’s high nitrate levels this winter | WHO-TV