My partner Tiffani Harrison and I ventured out to Glendon Campus on an overcast Wednesday afternoon on November 16th, 2016 in search of assigned stretch #6. Using the map shown below in Figure 1, we discerned the location our our 100 m riverbank stretch was blissfully located near the bridge (and the parking lot) meaning no crazy far hikes into the wilderness was in store for us!
Photographs – Interpretation and Explanation
Our photography started from the perspective on the bridge of the SE, SW, and NW view (shown below in Figures 2, 3, and 5). Figure 2 showcases evidence of previous river bank stabilization efforts of stone masonry. Unfortunately, further slumping of the bank has compromised the integrity of the masonry work and has resulted in the layered stones to crumble into the river.
Figure 3 illustrates further efforts of previous river bank stabilization, this time with the addition of wire cage around the stone masonry to prevent spillage into the river if further slumping occurs. This strategy has been more successful in stabilizing the bank and counteracting the natural slumping.
Below is an image cartooning the mechanics of stone masonry on a river bank1. While keeping the vegetation from spilling into the river, the stones provide a barrier at the perimeter edges of the river keeping the water body narrower and deeper while preventing sediment collapse which causes the river to be wider and shallower during times of high flow.
As shown in Figure 5, the NW side of the river had no previous efforts of bank stabilization so there was clear slumping of sediment and vegetation into the river water. Thus, making this side of the river more wide and shallow.
Next, we photographed from the NW side of the river to capture the view of the SE bank. This perspective is shown in Figures 6, 7, and 8.
Figure 8 depicts the slumping of a tree into the river, bypassing the efforts of the previous bank stabilization. Figures 9 and 10 shows the mechanism of slumping sediment containing vegetation2,3.
Lastly, we photographed the NW side of the river from the viewpoint of the SE side. As there was no previous bank stabilization effort, the sediment and vegetation had slumped into the river, exposing tree roots and fresh soil as shown in Figure 11 and 13.
At the very beginning of the river after the bridge on the NW side, there is some old bank stabilization efforts spanning only 10 m or so. The is shown in Figure 12 below
In conclusion, we witnessed some previous bank stabilization efforts on portions of our assigned river stretch #6, but not enough that the effects of sediment slumping were countered and prevented. Further efforts and investment into this area is required to avoid future bank slumping in order to maintain a healthy river system.