The Role of Headwater Wetlands in Altering Streamflow and Chemistry in a Maine, USA Catchment

TitleThe Role of Headwater Wetlands in Altering Streamflow and Chemistry in a Maine, USA Catchment
Publication TypeJournal Article
Year of Publication2011
AuthorsMorley T.R, Reeve A.S, Calhoun A.JK
JournalJournal of the American Water Resources Association
Volume47
Pagination337-349
Date PublishedApr
ISBN Number1093-474X
Accession NumberWOS:000288865100009
Keywordscatskill mountains, dissolved organic-carbon, first-order streams, groundwater discharge, groundwater slope wetlands, new-york, nitrate, nitrogen, riparian zone, runoff processes, seeps, storm runoff, surface-water, wetland functions
Abstract

Headwater wetlands, including hillside seeps, may contribute to downstream systems disproportionately to their relatively small size. We quantified the hydrology and chemistry of headwater wetlands in a central Maine, USA, catchment from 2003 to 2005 to determine their role in maintaining headwater streamflow and in affecting stream chemistry. A few of these headwater wetlands, commonly referred to as "seeps," were characterized by relatively high groundwater discharge. During summer base flow, seeps were the primary source of surface water to the stream, contributing between 40 and 80% of stream water. Comparisons of groundwater and surface water dominant ion chemistry revealed only slight differences at the bedrock interface; however, significant changes occurred at the shallow groundwater-surface water interface where we found decreases in total and individual cation concentrations with decreasing depth. Seep outflows significantly increased total cation and calcium concentrations in streams. Outflows at two seeps produced relatively high nitrate concentrations (88 +/- 15 and 93 +/- 15 mu g/l respectively), yet did not correspond to higher nitrate in stream water below seep outflows (2 +/- 1 mu g/l). We demonstrate that small wetlands (< 1,335 m2) can contribute to headwater stream processes by linking groundwater and surface-water systems, increasing the duration and magnitude of stream discharge, and by affecting stream chemistry, particularly during periods of base flow.

Short TitleJ Am Water Resour AsJ Am Water Resour As
Alternate JournalJ Am Water Resour As