|Williams, Mark -|
Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 25, 2011
Publication Date: N/A
Interpretive Summary: An interpretive summary is not required.
Technical Abstract: In many headwater catchments, streamflow originates from surface seeps and springs. The objective of this study was to determine the influence of seeps on nitrogen (N) dynamics within the stream and at the outlet of two adjacent mixed land use watersheds. Nitrogen concentrations in stream water were measured every 10 m along each stream. Samples were collected five times a year starting in April 2009 during baseflow and following storm events. Surface water at the seep top (i.e., emergence point) and seep bottom were sampled biweekly. Preliminary results suggest that seeps significantly contribute to and regulate stream N dynamics in both watersheds. Seep bottom N concentrations appear to be highly correlated to stream water concentrations throughout the year. Seep N concentrations could explain 74% of the seasonal variability in watershed outlet stream N concentrations. Seeps generally were N sinks; however, individual seeps function differently in terms of N retention. Some seeps had N removal rates of greater than 80%, while others acted as a source of N with removal rates of -10%. The results of this research suggest that although seeps are a very small part of the watershed, they potentially exert major controls on streamflow chemistry and hydrology.