That is about where the underground pipe was under the old roadway before the ES was used i think
Could it just be rainfall water the collected on the opposite side of the rebuilt road hidden from view draining off?
If rain hits the ES ledge it would drain off it and perhaps get dammed up behind the road in that low spot..so perhaps they put a drainage pipe under that road????
Hi janetjanet998, they armored the full basin at the road just behind the ES Weir spillway. There are no dark streaks or dark areas showing a water pooling or collection (to go to a "pipe"). If they were to place a pipe that allows water penetration from an Emergency Spillway Overflow, this penetration could be a weak point (pipe)- if it fails. Installing a pipe in the upstream road bank risks allowing an erosion flow underneath the shotcrete armoring, thus creating an erosion collapse via voiding under the armoring. This failure could defeat a large section of the armoring fairly quickly, leading to a "back head cutting" failure mode that caused the emergency evacuation of 188,000 people. A fully armored basin at the road will force waterflow to topple over the road, thus indirectly acting as an energy dissipator. note: I could be wrong, but if someone decided to insert a "failure" source into all of that expensive rock emplacement and shotcrete blanketing, someone should be "shotcreted"…
Note: (KC Burke) - the video shows the trucks creeping very very slowly, only one at a time & centered on the spillway bridge. Notice the other trucks are waiting for their turn to cross. That bridge has to have been enduring a significant load flexure repeated stressing from all of the heavy loads of rock, concrete trucks, etc during this whole crisis. This pic gave me a chance to point out (image) what I had mentioned upthread on the bridge.
