Glaciers are key geomorphic agents in mountain landscape evolution. Cirque glaciers dominate present-day alpine environments, and may be important in creating relief at the highest elevations. Field measurements of cirque glacier dynamics can provide constraints on rates of subglacial erosion; measurements of suspended and bedload sediment in proglacial streams are relevant for quantifying supraglacial and subglacial transport. If the rates of headwall backwearing are known, sediment transport in streams can be used to determine rates of subglacial erosion. In summer 2006, we installed stream gages at West Washmawapta/Helmet Mountain Glacier, a small cirque glacier located 30 km east of Golden, British Columbia. Water and sediment monitoring was conducted as part of a larger study examining cirque glacier dynamics, headwall backwearing, and subglacial erosion.
Stream gages were installed at two locations along the complex proglacial stream network, which incorporated melt water from an adjacent glacier, several streams exiting the glacier terminus, and at least four small lake basins. Stage and pressure data, conductivity, water temperature, and water turbidity were recorded every 15 minutes between June 25 and September 10, 2006. Stage measurements at the stream gages were constrained using both the salt dilution method and velocity meter measurements, and used to construct a rating curve relating stage/pressure and discharge. Water discharge showed strong diurnal variability, and ranged from ~1-5 m3/s over the period of measurement. Peak discharge occurred at ~2100 hours, lagging peak glacier melt by several hours. Preliminary analyses suggest discharge is sensitive to air temperature and glacier snow cover. Suspended sediment samples collected twice daily provide constraints on turbidity measurements; these data show a complex spatial and temporal pattern of sediment flux from the glacier and in the proglacial zone. Additional suspended sediment profiles, along with bedload transport sampling, provide a more detailed picture of sediment flux in the system.