Runoff Hydrology of a Low Arctic Drainage Basin

Abstract

<p>This is a study of the hydrology of a low Arctic drainage basin in the continuous permafrost region. The basin has a varied surface cover of upland tundra, wetlands and lakes. A water balance computed at the basin in scale determines the relative importance of various hydrological components including snowmelt, rainfall, inflow, evaporation and outflow. Studies conducted at the sites representative of uplands, wetlands and lakes quantify the magnitude and temporal variability of runoff. By combining the process and water balance studies results, an explanatory framework is developed for the spring and summer hydrology.</p> <p>Snowmelt is the largest input of water to the basin and runoff is one thirds greater than evaporation as a loss. Peak discharges occurs during snowmelt when the meltwater exceeds the storage capacity available in the basin. Snowmelt contribution is greater from the wetlands areas, but, because of a larger area extent, upland meltwater contribution is also significant. The wetlands areas provide a route through which lake and channel overbank flow and meltwater are conveyed to the basin output. Surface flow is the primary runoff process during snowmelt in both wetland an upland areas.</p> <p>In summer, evaporation is the major process through which water is lost from the basin. Upland areas become dry, but wetlands have enough stored water to sustain evaporation at potential rates. Runoff response to a rainstorm is negligible when the basin is dry, but is significant of previous storms have saturated the upland and the wetland areas. Storm runoff is produced first from hummocky areas at the base of hillslopes, then from uplands and finally from the wetlands. When all the parts of the basin contribute storm runoff the basin response will be both large and rapid. Stormflow recession is long for all storms.</p> <p>The upland-wetland-lake hydrological system examined in this study is typical of the North American low Arctic environment. Through an understanding of both the hydrological processes with each subsystem and the linkages between subsystems an explanation of the runoff regime of a low Arctic drainage basin is obtained.</p>