Nutrient retention in wetlands is controlled largely by water table dynamics, which can be inferred from watershed position and local topographic gradients.  Until recently, however, the resolution of the widely-available topographic data did not provide enough information to describe a wetland's setting in relation to the local contributing area and adjacent surface waters, and therefore to predict where these processes occurred.  We used high-resolution topographic data (1 m resolution, 15 cm vertical accuracy) obtained from Light Detection And Ranging (LiDAR) remote sensors to describe local topographic features along an entire stream network. 

Results/Conclusions

Geospatial analysis of a 350 km² watershed in central Pennsylvania indicated that nitrogen removal via denitrification and phosphorus retention due to sediment deposition, along with carbon accumulation, change predictably along stream networks and that these data can be used effectively to describe a wetland's landscape setting, predict wetness, and infer biogeochemical processes across entire watersheds.