Extreme Drought + Heavy Rain = Accelerated Erosion?

[dgw2jr]

I noticed the recent rains have caused some significant erosion at Sunderbruch. There's some typical Mtn Dew MTBer induced erosion as seen on Watermelon Pass but most of it seems to be natural, occurring around exposed roots and such. Some of the new erosion is pretty rough, almost like potholes in the trail.

So I'm wondering what the procedure is for repairing these eroded areas. I suspect we may need a better assessment of the damage before we can determine whether or not it's actually a problem, since I am just one opinion, and one dude's erosion is another dude's epic gnar.

[Russhole]

yeah that really sucks. there's like ten years worth of erosion done in one night. I would guess there needs to be some work done to some of the worst spots.

[jimithng23]

Braking bumps
Trails near the fall line
Years of abuse
Very dry summer

All adds up to accelerated erosion.

The Sunderbruch trail care crew will take care of the problem areas using the least intrusive methods possible in the coming months.

[DH001]

The drought in conjunction with user traffic have caused the soil to break down into individual particles which are easily transported by water. These are readily washed away by heavy rainfall when water cannot be shed off of the trail. Illiniwek had some major damage to the creekside switchback climb with the last high volume rainfall event as well and it was because the water was flowing down a section of overly steep trail. The ultimate fix is to keep the water from flowing down the trail and it can be accomplished by a number of methods (correcting outslope, installing grade reversals and knicks, realigning sections of trail which are too steep).

[dgw2jr]

Very clear and concise explanation, Drew. That's what I thought was going on. The dirt is getting pulverized. More so near hard surfaces like roots and rocks which explains the potholing near them.

[DH001]

The reasons you are seeing the pothole like features on the downhill side of roots or small ledges is because water gains energy as it free-falls off of the edge of these features and the angle at which the falling water hits the soil goes directly into dislodging soil particles. If the drop is large enough and the soil weak enough, the water will start to dig a hole as it dissipates energy. When water flows down or across a trail most of the energy is absorbed by the water itself trying to flow around and over things.

I have seen this phenomenon even during non drought conditions so I don't think the drought is the single biggest factor. However, it obviously doesn't make the situation better.