Spatial and temporal patterns of break‐up and ice‐jam flooding in the Mackenzie Delta, NWT

The Mackenzie Delta is covered in freshwater lakes that provide habitat for a myriad of species. The hydrology and ecology of these delta lakes are dominated by cryospheric processes, specifically spring break-up ice jams, which typically produce the largest hydrologic event of the year. Despite the importance of ice-induced flooding in the delta, the patterns and processes characterizing these events are poorly understood. In this paper, archived records at a dozen hydrometric stations in the delta for the period from 1974 to 2006, improved with information from remotely sensed imagery, are used to assemble a break-up chronology for the delta, and examine the spatial and temporal patterns of break-up flooding. Analysis of backwater level and discharge at the Mackenzie River at Arctic Red River (MARR) station are used to explain the physical rationale of the resulting patterns. Results highlight years of extensive delta flooding, and within the subset of significant flood years, two event types are identified: (1) ice-driven events, with high backwater levels at MARR associated with high levels in the southern and eastern/western delta, and (2) discharge-driven events, with extensive high-water levels in the mid/outer delta and along Middle Channel, despite lower upstream peak water levels. Temporally, the break-up initiation during ice- (discharge-) driven events occurs earlier (later) than the delta average. These occur later (earlier) in the time-series that is trending toward earlier break-ups. The MARR station is determined to be a suitable index of delta peak water levels for continued investigation into the hydroclimatic controls on extreme hydrological events in the Mackenzie Delta.

[1]  S. Bigras.  Hydrological regime of lakes in the Mackenzie Delta, Northwest Territories, Canada. , 1990 .

[2]  P. Sen.  Estimates of the Regression Coefficient Based on Kendall's Tau , 1968 .

[3]  F. Hicks,et al.  Modelling thermal breakup on the Mackenzie River at the outlet of Great Slave Lake, N.W.T. , 1997 .

[4]  B. Bonsal,et al.  Trends and Variability in Spring and Autumn 0 °C-Isotherm Dates over Canada , 2003 .

[5]  P. Marsh,et al.  Analysis of Spring High Water Events in the Mackenzie Delta and Implications for Lake and Terrestrial Flooding , 1994 .

[6]  Ming-ko Woo,et al.  Streamflow in the Mackenzie Basin, Canada , 2003 .

[7]  S. Beltaos.  Onset of river ice breakup , 1997 .

[8]  T. Prowse,et al.  Ice regime of the lower Peace River and ice‐jam flooding of the Peace‐Athabasca Delta , 2006 .

[9]  J. Magnuson,et al.  Historical trends in lake and river ice cover in the northern hemisphere , 2000, Science.

[10]  T. Prowse.  Environmental significance of ice to streamflow in cold regions , 1994 .

[11]  P. Marsh,et al.  The Flooding Hydrology of Mackenzie Delta Lakes near Inuvik, N.W.T., Canada , 1989 .

[12]  Philip Marsh,et al.  Lake abundance, potential water storage, and habitat distribution in the Mackenzie River Delta, western Canadian Arctic , 2007 .

[13]  Terry D. Prowse,et al.  RIVER-ICE ECOLOGY. II: BIOLOGICAL ASPECTS , 2001 .

[14]  T. D. Prowse,et al.  Effects of climatic variability and flow regulation on ice‐jam flooding of a northern delta , 1998 .

[15]  P. Pelletier.  A review of techniques used by Canada and other northern countries for measurement and computation of streamflow under ice conditions , 1990 .

[16]  Steven R. Fassnacht,et al.  Persistence of a scour hole on the East Channel of the Mackenzie Delta, N.W.T. , 2000 .

[17]  Joseph M. Culp,et al.  Ice breakup: a neglected factor in river ecology , 2003 .

[18]  V. Lalonde,et al.  Open-Water and Ice-Jam Flooding of a Northern Delta , 1996 .

[19]  T. Prowse,et al.  Strength Variability of Major River-Ice Types , 1993 .

[20]  T. Prowse.  River-ice ecology. I : Hydrologic, geomorphic, and water-quality aspects , 2001 .

[21]  Philip Marsh,et al.  The hydrologic regime of perched lakes in the Mackenzie Delta: Potential responses to climate change , 1996 .

[22]  W. D. Hogg,et al.  Trends in Canadian streamflow , 2000 .

[23]  Terry D. Prowse,et al.  Climatic control of river‐ice hydrology: a review , 2002 .

[24]  S. Beltaos.  River ice breakup processes : recent advances and future directions , 2007 .

[25]  Michael G. Ferrick,et al.  Analysis of river ice motion near a breaking front , 1991 .

[26]  Philip Marsh,et al.  EFFECTS OF CLIMATE CHANGE ON THE FRESHWATERS OF ARCTIC AND SUBARCTIC NORTH AMERICA , 1997 .

[27]  W. Rannie.  Breakup and freezeup of the Red River at Winnipeg, Manitoba Canada in the 19th century and some climatic implications , 1983 .

[28]  Terry D. Prowse,et al.  Temporal variations in river-ice break-up over the Mackenzie River Basin, Canada , 2008 .

[29]  H. B. Mann.  Nonparametric Tests Against Trend , 1945 .

[30]  J. Culp,et al.  Ecological effects of river ice break-up: a review and perspective , 1994 .

[31]  Terry D. Prowse,et al.  Thermal budget of river ice covers during breakup , 1989 .

[32]  Terry D. Prowse,et al.  Persistence of Water within Perched Basins of the Peace-Athabasca Delta, Northern Canada , 2006, Wetlands Ecology and Management.

[33]  D. Peters,et al.  Generation of streamflow to seasonal high waters in a freshwater delta, northwestern Canada , 2006 .

[34]  T. Prowse,et al.  The deterioration of freshwater ice due to radiation decay , 1990 .

[35]  J. Hobbie,et al.  General Features of the Arctic Relevant to Climate Change in Freshwater Ecosystems , 2006, Ambio.

[36]  W. Weibull.  A Statistical Distribution Function of Wide Applicability , 1951 .

[37]  T. Prowse,et al.  Assessment of annual high‐water events for the Mackenzie River basin, Canada , 2008 .

[38]  John E Hobbie,et al.  Climate Change Effects on Hydroecology of Arctic Freshwater Ecosystems , 2006, Ambio.