Kate Dwire

Kate Dwire is a Research Riparian Ecologist at the USDA Forest Service Rocky Mountain Research Station. She earned an undergraduate degree in biology from the University of California, Santa Barbara, a M.S. degree in Plant Ecology from the University of California, Davis, and a PhD in Riparian Ecology from Oregon State University. Her research interests include (1) the distribution of wetlands and riparian plant species and communities in relation to hydrologic and geomorphic variables and disturbance (natural and anthropogenic); (2) the influence of prescribed and natural fire on riparian plant species and communities; (3) organic matter dynamics (surface and subsurface) in stream-riparian ecosystems.

Presentation Abstract:

The Contribution of Individual Springs to the Chemistry of Fool Creek, Fraser Experimental Forest.

Kate Dwire, Chuck Rhoades, Natalie Quiet and Mark Dixon

We examined spatial patterns in dissolved oxygen, temperature and inorganic and organic chemistry of water emerging from fifty springs in the Fool Creek watershed at the Fraser Experimental Forest, Colorado. The springs extend from above treeline at 3500m to 3000m within subalpine forest. Conductivity, pH and ANC of spring water average 42 µS / cm, 7.0, and 360 meq/ L, respectively. In general, spring water was less chemically dilute than streamwater though spring chemistry differed with elevation and proximity to the stream channel. Concentrations of most dissolved inorganic ions were lowest in springs near treeline, and both spring water and streamwater chemical concentrations increased at lower elevation. Spring water contained higher concentrations of sodium, potassium, chloride and sulfate than streamwater. Nitrate was also higher, but DOC was lower and DON did not differ compared to streamwater. In general, spring water was well oxygenated, and DO was highest in the coldest and most vigorously flowing springs. Spring water remained 3 deg C cooler than streamwater during summer months. The more dilute chemical composition of the treeline springs suggests that they are fed by recent snowmelt. In contrast, springs with the highest ion concentrations emerge from faulted portions of the watershed where groundwater may follow deeper flowpaths and contact weatherable materials. The chemical composition of streamwater was most similar to spring water emerging near the channel. The high discharge and their relative abundance suggests that these springs may have a predominant influence on basin-scale aqueous chemistry.