Observations of Washington State Landscapes, Geology, Geography, Ecology, History and Land Use
Wednesday, June 16, 2010
As an engineering geologist I on occasion work on retaining wall designs. I am rather proud of my own retaining wall work. I used rocks from an old wall. The cut slope that the rocks front is a mix of soil and highly weathered weak siltstone and sandstone bedrock of the Chuckanut Formation at one end and a mix of bricks and soil and rocks at the other end. The cut slope was created when the City of Bellingham regraded the alley in the 1930s.
I had to rebuild part of the wall after I took it down as part of a sewer line replacement. The old garage could not be accessed due to the steepness of the new slope between the alley and the garage. So the "driveway" was no more than a wide path that was plant covered. When we dismantled our chimney about 10 years ago, the good bricks were mostly given away to friends that built patios with them. The broken bricks then were used to partially fill the driveway and I used the old wall rocks that lined the sides of the driveway to build the retaining wall. (Just a note - as much as I like fire places as a geologist I have a fear of brick chimneys)
Since then I have selectively pushed various drought tolerant plant seeds into the spaces between the rocks. The wall has put on a nice display in the alley this past spring.
Dan McShane is an engineering geologist with Stratum Group, a geology and environmental consulting company based in Bellingham, Washington. Dan has been reading Washington State landscapes since driving across the Horse Heaven Hills with his father and brother in 1970. Dan's wife has started painting Washington landscapes. The intent of this blog is to help all Washington travelers better understand the landscapes we see and share field observations.