Paper No. JAWRA-08-0214-P of the Journal of the American Water Resources Association (JAWRA) Discussions are open until six months from print publication.
Sediment Source Assessment in a Lowland Watershed Using Nitrogen Stable Isotopes1
Article first published online: 6 OCT 2010
© 2010 American Water Resources Association
JAWRA Journal of the American Water Resources Association
Volume 46, Issue 6, pages 1192–1204, December 2010
How to Cite
Fox, J. F., Davis, C. M. and Martin, D. K. (2010), Sediment Source Assessment in a Lowland Watershed Using Nitrogen Stable Isotopes. JAWRA Journal of the American Water Resources Association, 46: 1192–1204. doi: 10.1111/j.1752-1688.2010.00485.x
- Issue published online: 30 NOV 2010
- Article first published online: 6 OCT 2010
- Received November 17, 2008; accepted August 11, 2010.
- sediment transport;
- streambed storage
Fox, James F., Charles M. Davis, and Darren K. Martin, 2010. Sediment Source Assessment in a Lowland Watershed Using Nitrogen Stable Isotopes. Journal of the American Water Resources Association (JAWRA) 46(6):1192–1204. DOI: 10.1111/j.1752-1688.2010.00485.x
Abstract: Sediment sources and transported sediments were sampled in a lowland watershed with pronounced fine sediment storage in the streambed. Sediments were analyzed for carbon and nitrogen content and stable nitrogen isotopic composition. Analysis of the data shows that temporarily stored streambed sediments dominate the sediment load during moderate- and low-flow hydrologic events. Modeling of sediment transport and nitrogen elemental and isotopic mass balance was performed for the watershed for a 12-month time period using a continuous, conceptual-based model. The model results show that during moderate- and low-flow hydrologic events, the streambed is slowly downcutting. During very high-flow hydrologic events, deposition is pronounced in the streambed and sediment is replenished to the bed. Nitrogen model results show that elemental and isotopic nitrogen of streambed sediments vary substantially over the simulation period. In this manner, the streambed in a lowland watershed functions as a temporary storage zone that, in turn, can impact the nitrogen elemental and isotopic signature of sediments. The variation could significantly impact estimates of sediment provenance using nitrogen tracer-based methods. Future work should consider both hydrologic and biogeochemical control on the nitrogen isotopic signature of sediments in small lowland watersheds and streams where a significant portion of deposited fines are temporarily stored.