Heavy rain storms often result in a strong surge of water to the river. Some rain falls directly into the river, but more significantly, it runs across the land, picking up pollutants and sediment, especially around areas that have been altered by people. Wil Wolheim, a researcher at UNH, is studying how storm events mobilize nutrients. Nitrogen and phosphorus concentrations seem to increase with heavy rain. Weekly or monthly samples miss a lot of data, so he has installed in-site sensors to provide continuous tracking of several key water quality measurements. The equipment must endure strong currents and collisions with debris. The information gathered, however, will provide valuable insights into when nutrient concentrations change and how long the nutrients are retained in the river.