IMPORTANCE OF WETLAND DRAINAGE IN A HIGH-ELEVATION, SNOWMELT-DOMINATED CATCHMENT, SENATOR BECK BASIN, SAN JUAN MOUNTAINS, SW COLORADO

Snowmelt is a major contributor to streamflow in high-elevation headwater basins. Drainage from wetlands in these basins may be crucial to maintain baseflow following snowmelt, which is integral for late-season downstream flow. Climate change may affect the timing, amount, and form of precipitation that falls in these basins, potentially impacting wetland hydrology. This talk will examine streamflow characteristics in the Senator Beck Basin (SBB), San Juan Mountains, SW Colorado, to study how the timing of peak snow water equivalent (SWE) and snowmelt influences when baseflow due to wetland drainage becomes significant, determined when baseflow composes 15% or more of post-peak streamflow. It has been observed that when the stream is dry above the wetlands in the SBB, a downstream gauge still recorded flow. Daily stream discharge and specific conductance have been recorded at the SBB gauge since 2005. These data were used to estimate baseflow contribution to streamflow via the Conductivity Mass Balance method. SWE values are recorded at a nearby NRCS snow telemetry (SNOTEL) station. The timing of peak SWE and snow all gone (SAG) are compared to total streamflow and to baseflow discharge. Three years of snowmelt and streamflow data are examined: dry, average, and wet. Results for the three years indicate that the timing of significant baseflow for the wet year occurs approximately 30 days later than for the dry year. The stream from the SBB is a headwater tributary to the Colorado River. Therefore, it is imperative to quantify wetland discharge. High-elevation wetlands are known to occur throughout many of the world’s mountains. These wetlands may provide significant baseflow to maintain streamflow during the latter part of the year. Changes in hydrologic processes can have compounding effects on downstream flow. This work will provide a better understanding of the connection between snowmelt, wetland discharge and recharge, and baseflow in high-elevation headwater streams. Future climate variability may influence the timing, amount, and form of precipitation, thus modifying the local water budget and subsequent baseflow discharge.