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Thesis Presentation


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Thesis proposal, including background information and research methods

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Thesis Presentation

  1. 1. Post-Little Ice Age Fluvial Development Patterns in Southern British Columbia Coast Mountains Natasha Cowie April 14, 2010 Tiedemann Glacier
  2. 2. Outline Proglacial physical characterization Conceptual models of proglacial streams Research objectives Site selection Timeline Logistics and safety Opal Cone and glacial outwash, Garibaldi Provincial Park
  3. 3. Glacial systems: indicators for hydroecological response to climate change High climatic sensitivity, low human perturbation Implications for water resource management and hydroecology Unique hydrologic and geomorphic processes Remnants of moraine-dammed lake and channels, Bridge Glacier
  4. 4. Physical process characteristics of glacial systems High temporal variability Sharp downstream gradients Strong altitudinal controls Processes superimposed on historical template Glacier de Fleur des Neiges and stream channel, Garibaldi Provincial Park
  5. 5. Conceptual models of proglacial stream development Sidle and Milner 1989 (Glacier Bay, Alaska) Chronosequence study of five streams 30-100 years post-deglaciation Physical processes and riparian vegetation Gurnell et al. 1999 (European Alps) Major simplifying assumptions: Does not include downstream discharge and sediment regimes Only valid for relatively wide river corridors Smith et al. 2001 (French Pyrenees) Adds temporal scale to Gurnell model
  6. 6. Altitude and advance/retreat rates as proglacial influences (Gurnell et al. 1999) Rapidly retreating glaciers at high altitude have sediment-regime dominated proglacial zones (b) Rapidly retreating glaciers at low altitude have transitional, sediment regime- and vegetation-influenced zones (c) Many factors omitted, most significantly valley train slope and aspect From Gurnell et al. 1999
  7. 7. Hydrogeomorphological context for ecological processes (Smith et al. 2001) (A) Relationships between climate and glacial behaviour (B) Feedbacks and links between proglacial water sources and stores Physical processes underpinning suite of disturbance regimes with ecological implications Different processes dominate at different timescales From Smith et al. 2001
  8. 8. Research objectives To test and evaluate existing conceptual models of postglacial stream development Existing models are conceptually sound, but highly generalized and simplified (Gurnell) or site specific (Milner) To develop a regionally specific conceptual model of postglacial stream development for southern Coast Mountains Emphasizing geomorphology Frame in tectonic and glacial history of the landscape Predictions for future stream development patterns
  9. 9. Research expectations Significant impact of lakes Impound sediment Attenuate outwash floods Slope and aspect as major channel and vegetation controls Not included in previous models Stability of glacier terminus (mass balance) correlated with channel and riparian development
  10. 10. Research timeline April-June 2010: air photo and satellite image analysis Evaluating channel type and riparian zone condition of less accessible areas July-October 2010: site surveys October 2010-January 2011: data analysis Regression analysis, sediment rating curves Mapping of surveyed stream reaches and cross-sections January-May 2011: writing May-June 2011: expected completion
  11. 11. Site selection Southern British Columbia Coast Mountains Eliminating inter-regional variation but highlighting intra-regional variation Post-Little Ice Age stream reaches LIA represents the maximum Holocene extent of ice coverage (peak in 17th-19th centuries) Reliable event chronologies Site selection Dendrochronology and lichenometry studies Air photographs and satellite imagery
  12. 12. Study sites Field sites Garibaldi Provincial Park Strathcona Provincial Park Bridge Glacier (possible) Air and satellite image analysis Lillooet Glacier Bella Coola area (multiple small glaciers) Tzeetsaytsul Glacier (Tweedsmuir Provincial Park) Mount Waddington (air and satellite images) Lillooet Glacier
  13. 13. Helm Glacier in 1928 (top, BC Archives I-67145 and 67146) and 2002 (J. Koch) from Koch et al. 2009 Warren Glacier in 1912 (top, W.J. Gray), 1928 (middle, BC archives I-67560) and 2001 (J. Koch) from Koch et al. 2009
  14. 14. Lillooet Glacier Terminus and Forefield in 1965 British Columbia airphotos BC5149-052, BC5149-053. Copyright© 2003 Province of British Columbia. From Reyes and Clague 2004.
  15. 15. Lillooet Glacier Terminus and Forefield in 2010
  16. 16. Site surveys 10-12 field sites Longitudinal, latitudinal, altitudinal, and temporal variability Planimetric surveys along thalweg, channel cross-sections Mapping major fluvial features Riparian vegetation classification, functional wood in channel Substrate particle size estimates Water samples for suspended sediment analyses Stream discharge, diel variations in water temperature
  17. 17. Logistics and safety Budget Primary expenses transportation (gas), food Field assistant salary included Access Most sites accessible by trail, lightweight equipment Within provincial parks Safety Wilderness First Aid training Satellite phones Park staff notification
  18. 18. Questions? Garibaldi Provincial Park