Re: Alistair Taylor’s column of April 29, 2016: “Rip Rap is Crap.”
I’m here to give you an example of when Rip Rap is not, as your apparent narrow view of it states, “crap.”
I live on the banks of the Campbell River where in 1990 some riverfront properties had large portions of their yards stripped away by a BC Hydro knee-jerk decision made when a light flashed miles away in Burnaby on a billboard-size display of our province’s electrical grid. History shows that as well as the irreparable damage done to these properties, the spawning channel adjacent to the Gold River highway was flushed out.
The federal government proceeded to repair the riverbanks with – you guessed it – large boulder rip rap to protect the banks from the North end of 20th avenue downstream to the old log dump. The boulders are at street height from 20th Avenue to just downstream from Maple St., then they continue all the way down to the old log dump at a lower height. This section of rip rap is at a lower level for a very practical, beneficial reason; that is, it forms a “riparian bench” that allows nutrients and soil washed down from the Quinsam River to be trapped when the tide recedes thus allowing natural river bank intertidal vegetation to be established.
If this rip-rap wasn’t here we would have continually eroding yards and the river would, in following it’s natural course, erode through the Myrt Thompson trail . There would be no riparian bench and scant vegetation. In their infinite wisdom, the engineers that designed the river bank rip-rap repair missed one very key element called geo-textile. Had this been considered here and at the foreshore, the process of infiltration could have been mitigated. Geo-textile allows water to seep through as the tide floods and when it recedes the fines are trapped behind it thus preventing continual erosion.
At the foreshore another oversight not providing geo-textile in design of the new “natural slope” beach will result in the same process of infiltrating water drawing fine soil back out as the tide recedes. Just to close…the former natural foreshore prior to infilling of that shoreline was not the sandy expanse we usually associate with the word “beach.” It was semi-estuarine habitat .