Sunday, January 20, 2013

Trail Maintenance Causes Erosion

I did my usual Sunday run on Silverado Motorway. My legs were pretty dead last weekend but were ok today. I noticed that someone did trail maintenance sometime during the week. This consisted of the usual cutting brush and putting in water diversion dams. They also installed some of these metal drain pipes like those installed on Harding Truck Trail after the big fire.

While running and thinking about these actions, I decided both these actions would exacerbate water caused erosion rather than limiting it.

  • Cutting brush is obvious. If you remove brush and especially if you kill the plant, you take away brush that slows the flow of rain and you kill roots that would help hold soil in place.
  • The idea behind water diversion dams is that if rain runs down the trail and causes erosion, a water diversion dam will divert water off the trail before the water picks up too much speed. However there is little erosion of the trail due to rain. The only water related erosion on this trail is where water is diverted off the trail down the side of the mountain. One of the gullies that results is about 15 to 20 feet deep. So by diverting water off the trail, they'll just cause more of the same erosion. The drain gutters that they put in will just speed up the water and focus it on a particular spot on the hillside, causing even worse erosion. If you want a good indication of what this will do, look at what has happened on Harding Truck Trail.
This shows one gully off Silverado Motorway caused by the diversion of water off the trail.
This link shows pretty severe erosion at about the 3 mile mark of Harding Truck Trail, pretty obviously caused by one of the rain gutters installed since the fire

Enough of that negativity. I was back down to 138 pounds this week and had a few days where my legs felt dead. I have a strategy though and the main idea is to get complete protein, for instance by mixing peanut butter with my oatmeal.

Mon Tue Wed Thu Fri Sat Sun
10 miles on Oxford track in about 1:33 5x1k 9.1 mile Irvine trail loop 3xRose Hills Road climb - foot was tight Nothing (went to Cirque Du Soleil with family 10.5 Trail loop in Rowland Heights. Stopped and rested on one climb Silverado Motorway in 1:43 - not bad

No comments: