Mar 22, 2015

Snow-melting in Canadian Prairies

Figure- Prairie Ecozone boundary (Source: Esri Canada)
Snowmelt is one of the most significant hydrologic process in the Prairies. In hydrology, snowmelt refers to the melting and subsequent processes regarding snow. It is generally occurs at the end of winter, but mid-winter thaws and melt are not rare phenomena. Snowmelt freshet recharges soil moisture and groundwater and replenishes lakes, reservoir and river in Prairie region (Norum et al., 1976). Solar radiation energy flux plays a vital role for Prairie snowmelt (Male & Gray, 1981). Shortwave radiation is the dominant part of solar radiation energy and snow surface albedo controls the incoming radiation flux. Granger & Gray (1990) observed that albedo decrease of 0.0061 per day during pre-melt period and 0.071 per day during melt period in the prairies. The major features of snow melting in Prairies are-
  1. Energy budget
  2. Turbulent heat exchange
  3. Snowmelt rate
  4. Infiltration and percolation in frozen soil
  5. Depressional storages in Prairie potholes
The Great Plains in the Canadian provinces of Alberta, Saskatchewan and Manitoba are known as Canadian prairie region. The hydrology of the Canadian Prairie region consists of long winter of 4-5 months, snowmelt runoff events to generate river flow, low baseflow, high seasonal and annual streamflow variability, and climatic variability. Runoff from snowmelt freshet in mid to late April is normally the largest runoff event of a year. The impact of rainfall in summer is modest and high evaporation rate consume the excess rainfall (Fang & Pomeroy, 2008; Pomeroy et al., 2007). The topography of prairie is the result of historic glacial movement. Moraines, flutings, outwash plains, glacial outburst valley, sand dunes, glacially dammed lakes are some topographic features of the prairies. Prairie potholes are the remnant of glacier existence (Shook et al., 2013).


Reference:
Norum, D. I., Gray, D. M., & Male, D. H. (1976). Melt of Shallow Prairie Snowpacks. Canadian Agricultural Engineering, 18(1), 2–6.

Male, D. H., & Gray, D. . (1981). Snowcover ablation and runoff. In D. M. Gray & D. H. Male (Eds.), Handbook of Snow: principles, processes, management & use (pp. 360–436). Ontario: Pergamon Press Canada Ltd.

Granger, R. J., & Gray, D. M. (1990). A net radiation model for calculating daily snowmelt in open environment. In Paper presented in 8th Northern Res. Basins Symposium (Vol. 21, pp. 217–234). Abisko, Sweden: Nordic Hydrology.

Fang, X., & Pomeroy, J. W. (2008). Drought impacts on Canadian prairie wetland snow hydrology. Hydrological Processes, 22(15), 2858–2873. doi:10.1002/hyp.7074

Pomeroy, J. W., Gray, D. M., Brown, T., Hedstrom, N. R., Quinton, W. L., Granger, R. J., & Carey, S. K. (2007). The cold regions hydrological model: A platform for basing process representation and model structure on physical evidence. In Hydrological Processes (Vol. 21, pp. 2650–2667). doi:10.1002/hyp.6787

Shook, K., Pomeroy, J. W., Spence, C., & Boychuk, L. (2013). Storage dynamics simulations in prairie wetland hydrology models: Evaluation and parameterization. Hydrological Processes, 27, 1875–1889. doi:10.1002/hyp.9867