Arctic hydrology: a water balance study of Imnavait Creek and Kuparuk River watersheds, Alaska

Increasing air temperatures are expected to change streamflow patterns in Arctic watersheds. However, the hydro-meteorological datasets necessary to evaluate these changes remain limited in the Arctic. We revised and updated a unique hydrologic dataset from Arctic Alaska with field measurements of continuous streamflow, precipitation, and evapotranspiration to identify changes in the hydrologic cycle. We analyzed water balance components and peak streamflow in Imnavait Creek, Upper Kuparuk River, and Kuparuk River during snowmelt and summer periods. Field measurements show that summer streamflow (mid-June to late-September) has increased in volume and magnitude. While snowmelt runoff still constitutes a sizable portion of annual runoff (28%–58%), the relative proportion of summer runoff is notably increasing. High interannual and spatial variability is observed for both rainfall and summer runoff, whereas comparatively lower interannual variability is observed for snowmelt runoff. This paper compares streamflow changes occurring at three watersheds of varying sizes and identifies reasons for observed changes using snow, rainfall, and evapotranspiration measurements. We also provide hydrologic analysis for design considerations at Arctic Alaska communities, the Dalton Highway, and the oil pipeline; as this infrastructure may be at risk of increased erosional damage due to more frequent and higher magnitude summer flow events.