So some history on this project. Rich had been out to see this years in advance, there had always been problems with this one location and erosion. It was after the big Marshall fire right in that area that they started noticing more problems than normal. This was due to the fire wiping out everything that would have usually taken in some of the water. They had created a plan that involved removing the 18 inch culvert for a 3 foot one with another pipe leading down the slope. All of this was to be at a certain angle with 10 inch rock preventing it from eroding. What was in fact done was two 3 foot culverts side by side, without a long enough rock area to prevent erosion, and without a critical dip in case of an overflow.
On the intake side, there was definitely some erosion showing that the pipes were possibly put too low and was allowing the stream to erode the surface. The big problems were on the downstream side. Next to the culverts was a huge gash in the sides where they had fallen into the stream. The rocks were not 10 inches but rather giant boulders which had now also fallen in from the ravine. Most shocking was the fact that two trees were currently lying over the ravine since their root ball had fallen out of the hillside.
The problem with this location is that no one was there to see it. Trying ot figure out what happened so we could avoid it in the future was like attempting to figure out a crime scene. What we seemed to have decided was that because the culvert didn't have a pipe leading down the slope, that the water had moved under the rocks to eat away at the soil. This continued to cut under the rocks leading to a destabilization of the hillsides. This led to them falling into the stream. Another thing we noticed was a large amount of water was not flowing through the culverts. They were actually flowing under the left culvert and out of the cuts where the streambank sides had fallen in. The fact that they water was seeping out showed that it was possible the water was percolating to the clay layer and then moving above the clay layer. This would encourage the land slide we saw.
Another contribution to the flow was actually something I noticed. Being a bit of a scaredy cat, I didn't particularly want to get under the culverts which had so recently had a boulder slide. It didn't seem like a good way to go considering I was only there as an intern. So while they were all looking closely at the culverts, I was looking at the road. The road had originally been pure sand and since Rich's first visit, they had managed to grow some grass on it so that it would have less erosion. They had also installed water bars to direct the water off the road. The exact spot we were also had a layer of hay on it. I was looking at the erosion on the upstream side and was trying to figure out if maybe more water on the upstream was having an effect. It was then that I noticed all the hay was pointing the same direction from the road to the upstream side. I felt just like Aragorn in Lord of the Rings when he's tracking the hobbits (geeky I know). I had managed to figure out something I had not seen from clues shown on the land. It was really exciting to know that I had found a clue in the larger mystery of what happened at those culverts on the 26th.
There was a lot of discussion of next steps on this project. The RCD did have funds for road improvement, but they believed this would be a much larger scale than they usually did. There was also an issue of that this was not the first time everyone had been out to see this. The fact that Fish and Game had ignored the first time NRCS had supplied them with a plan was not working in their favor. However, there was also a discussion that a lot of the materials were already available since they used the same products, just didn't install them correctly. The following are some of the pictures from the location. You can truly see how bad the damage was.
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