This project develops new engineering approaches to address science questions about loading of nitrate to watersheds: how geologic setting, land use and terrain influence loading; the relationship between flow mixtures and nitrate loads; and the feasibility of using surrogate measures for estimating basin scale nitrate dynamics in space and time.  The engineering approaches are two-pronged.  (1) Commercially available nitrate, conductivity, temperature, and pressure sensors will be installed in an array that will sample at sub-daily frequencies and communicate via cell phone technology in real time to a central computer.  (2) Existing mission agency data will be used to develop a statistical algorithm based on information theory to identify minimum spatial and temporal spacing of sampling necessary to reduce uncertainty to a prescribed level. This algorithm will be validated with the newly collected data.