Jericho Beach is a sandy crescent beach on the southwest side of English Bay, west of Kitsilano and east of Spanish Banks. I'm not sure what the beaches along this side of the bay looked like before steam shovels arrived, although I would have expected substantial eastward drift from Point Grey and maybe a more continuous beach east towards Kitsilano. Groins and other historic modifications have segmented this shoreline into a series of pocket beaches - and left no beach at all in some places. Next trip I'll have to explore Locarno and Spanish Banks.
I once heard that it suggested that these beaches are supplied by the Fraser - maybe, though I suspect the eroding bluffs at Point Grey are the more likely source. Not that the Fraser doesn't loom just around the point to the southwest.
Spanish Banks shows up in 1898 original hydrogaphic surveys as one lobe of a pair of sand bars connected like a pair of lungs draped around the headland. The supply bar being another sand bar of similar dimension at the outlet of the shallow North Fraser river channel where it spilled over the tidal flats.... since that time the shallow connecting band that was the seasonal transport zone between the two sand bar lobes has been dissected with a dredged shipping channel, a rock jetty, and so forth.... wave action movement of tidal flat sediments is intercepted by the jetty or removed to mainatin log booming grounds, dredged river sands are either diverted or disposed to deep water to the designated Environment Canada ocean disposal site rather than feeding the historic transport regimes around to Spanish Banks....... the broad shallow surf zone over that sand pathway that historically dissipated storm waves against the headland has narrowed as the sediment supply has been cut off and the near shore depths have deepened... erosion rates have increased dramatically relative to historic... Vancouver Parks Board has elected to address dynamics of shoreline interface due by starting to rip rap the foreshore along the seawalk as it erodes.....there is no monitoring or the sand bank elevation profiles, there are about 6 jurisdictions involved... there is no sediment management plan for the Fraser Delta or Spanish Banks... ....the UBC Museum of Man and the University presidents house sit on top of the at risk bluff..... ironic that here is no UBC education or research on coastal management or engineering remaining with such a fascinating research topic at the front doorstep.... the last capital project solution was nourishing of the bluffs fringe beach with imported cobble.... sea level rise and increased storm events will add to the mix.... such is the state of coastal management and awareness in B.C.
ReplyDeleteThanks for the elaboration on the sand source. I know a little of the history of the UBC bluffs, but clearly should do some more homework on the Fraser material. Your explanation helps me understand a little better how Fraser sediment might get to the north side of the headland, which had puzzled me.
ReplyDeleteNow I need someone to send me a complete history of the English Bay beaches ... which I know must have a rich history, and a largely artificial one, I assume!