Water Stewardship Information Sources
| Citation | Millard, T. 2003. Schmidt Creek Sediment Sources and the Johnstone Strait Killer Whale Rubbing Beach. Forest Research Technical Report, TR-025. Vancouver Forest Region. |
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| Organization | FLNRO |
| URL | https://www.for.gov.bc.ca/rco/research/georeports/tr025.pdf |
| Abstract/Description or Keywords | The Robson Bight Ecological Reserve was established in the early 1980’s to protect killer whale habitat. Killer whales frequently use the area in the summer months, and in particular rub themselves on well rounded pebbles on a beach to the east of Robson Bight. Two reports identified Schmidt Creek as the probable source of sediment for the beach (Peel Creek is the local name for Schmidt Creek used by Western Forest Products). A monitoring program supported by both the Vancouver Forest Region and Western Forest Products investigated: • Whether sediment sources within Schmidt Creek were affected by forestry; • Whether changes to the rubbing beach were likely should sediment output from the watershed change. Large natural landslides in Schmidt watershed that occurred between 1934 and 1977 suggest that in decades past there have been large introductions of sediment to the beach system. These episodic natural sediment inputs in the past have been larger than logging-related sediment inputs. However, short term sediment input to Schmidt Creek has been significantly affected by forestry, with an approximate doubling of the amount of sediment delivered to Schmidt Creek since 1987. The rubbing beach is composed primarily of a poorly sorted sandy gravel similar to sandy gravels found on beaches closer to Schmidt Creek. This indicates that longshore transport of sediment from Schmidt Creek delivers similar material to each beach. Although the original material delivered to each beach is similar, the appearance of the rubbing beach is very different since it has the well sorted pebble wedge on top of the sandy gravel sediment. This wedge is the result of a wave sorting process that removes the sand from the surface of the sandy gravel sediment, resulting in a lag deposit of pebbles. The rubbing beach is exposed to the dominant easterly wave energy, and it is likely that this higher energy wave environment produces the better sorting present on the rubbing beach. The beach profile and sediment characteristics of the killer whale rubbing beach depend on many factors. The amount and type of sediment delivered to the beach are undoubtedly fundamental in determining beach characteristics. However, it appears that wave transport and the resultant sorting of sediment are the critical factors in determining the nature of sediment on the rubbing beach. Forestry activities appear unlikely to affect the rubbing beach, but given the nearly unique use of the beach by killer whales, management of the area should be cautious. Robson Bight Ecological Reserve, Tsitika, wildlife habitat, killer whales, sediment, Peel Creek, Schmidt Creek, beach processes, longshore transport. |
| Information Type | report |
| Regional Watershed | Vancouver Island North |
| Sub-watershed if known | |
| Aquifer # | |
| Comments | |
| Project status | complete |
| Contact Name | Tom Millard |
| Contact Email | [email protected] |