Much of our research points to the significant interactions between wetlands, hydrology and water quality. Wetlands alter surface runoff via their shape which slows and extends the delivery of runoff to a river network, especially critical for extreme events. In addition, wetlands transform and remove contaminants in surface runoff via assimilation by aquatic plants and transformations by associated microbes. Using field measurements we are quantifying the spatial heterogeneity of water chemistry and denitrification within constructed agricultural treatment wetlands. We are also considering the effect of changes in hydrology on riparian wetlands by modeling long-term patterns in flooding and local flow characteristics to predict changes in wetland vegetation.