Streamflow and sediment transfer from a mountainous high Arctic watershed, northern Ellesmere Island, Canada

• Main Author: Hardy, Douglas R
• Language: ENG
• Published: ScholarWorks@UMass Amherst 1995
• Subjects: Geology|Hydrology|Geography
• Online Access: https://scholarworks.umass.edu/dissertations/AAI9541114

The Lake C2 watershed at Taconite Inlet (82$\sp\circ$50$\sp\prime$N; 78$\sp\circ$00$\sp\prime$W) was the site of a three year project (1990-92), to investigate hydrological processes in the context of contemporary climate. The watershed is 21 km$\sp2$ in area, and 9 percent glacierized. This study was done in conjunction with a larger research effort, aiming to reconstruct paleoclimate using laminated lake sediments. A continuous record of discharge, determined by stage-discharge relations, and short-interval sampling of suspended sediment concentration (SSC), permitted the production of hourly time series. In addition, two weather stations logged hourly temperature, humidity, wind and complete radiation data at 7 m and 520 m a.s.l. The upper station was located close to the median watershed elevation. Mean daily air temperatures were rarely higher than 5$\sp\circ$C during the study periods, and the two weather stations revealed frequent temperature inversions. Precipitation events were small in magnitude ($<$13 mm d$\sp{-1})$, and primarily in the form of snowfall. Streamflow began June 9, 4 and 22 for the three years, respectively. Discharge followed a pronounced diurnal rhythm, especially during the brief nival flood. Maximum discharge was 4.0 m$\sp3$ s$\sp{-1}$. SSC fluctuated in close correspondence with discharge, and the highest measured concentration was 555 mg L$\sp{-1}$. Each year, approximately 50 percent of the suspended sediment discharge (SSQ) occurred during only 10 percent of the field season. Daily SSQ was strongly associated with air temperature at the median watershed elevation (r = 0.70, 0.92; entire field seasons 1991, 1992). These results demonstrate that sediment transfer to Lake C2 is a response to snowmelt. Among meteorological variables measured at weather station Alert (ca. 225 km east), rawinsonde sounding temperatures at 600 m were most closely associated with daily SSQ into Lake C2. Accordingly, an exponential equation, based on pooled 1990 and 1992 data, was used to predict daily watershed SSQ for the period of record (1951-89). The series of annual predicted sediment loads were found to be in excellent agreement with a normalized varve thickness series. This study indicates that laminated sediments in Lake C2 contain a high-resolution record of regional summer temperature.