Water Stewardship Information Sources
| Citation | Tunnicliffe, J. F. and Church, M. (2011), Scale variation of post-glacial sediment yield in Chilliwack Valley, British Columbia. Earth Surf. Process. Landforms, 36: 229–243. doi: 10.1002/esp.2093 |
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| Organization | UBC |
| URL | http://onlinelibrary.wiley.com/doi/10.1002/esp.2093/abstract |
| Abstract/Description or Keywords | drainage basin;Holocene Epoch;para-glacial;sediment budget;sediment yield Abstract The Holocene volumetric sediment budget is estimated for coarse textured sediments (sand and gravel) in a large, formerly glaciated valley in southwest British Columbia. Erosion is estimated by compiling volumetric loss estimated in digital elevation models (DEMs) of gullied topography and by applying a non-linear diffusion model on planar, undissected hillslopes. Estimates of steepland yield are based on estimates of post-glacial deposition volumes in fans, cones and deltas at the outlets of low-order tributary catchments. Erosion of post-glacial fans and tributary valley fills is estimated by reconstructing formerly continuous surfaces. Results are classed by catchment order and compared across scales of contributing area, revealing declining specific sediment yield (in m3 km−2 a−1) with catchment area for the smaller tributaries (<10 km2) and increasing specific sediment yield for larger tributaries and Chilliwack Valley itself. Approximately 60% of mobilized sediment is redeposited in first- to third-order catchments, with lesser proportions stored at the outlets of higher order catchments. A simple network routing model emphasizes the significant sediment flux contributions from colluvium, drift blankets and gullies in steeper terrain. As this material is deposited at junctions within the lower drainage network, an increasing proportion of material is derived from remnant valley fills and para-glacial fans in the major valleys. Yield from lower-order, steepland catchments tends to remain in storage, indefinitely sequestered on footslopes. These observations have implications for modelling the post-glacial sediment balance amongst catchments of varying size. After 104 years, the system remains in disequilibrium. The critical linkage lies between low-order, hillslope catchments ( |
| Information Type | article |
| Regional Watershed | Lower Fraser |
| Sub-watershed if known | Chilliwack River |
| Aquifer # | |
| Comments | |
| Project status | complete |
| Contact Name | Jon Tunnicliffe |
| Contact Email | [email protected] |