Thursday, 14 February 2013

Gully erosion

This video looks at gully erosion, how it forms, how it can drain the land and kill vegetation, and how it could be managed.

Col Stanton, long time soil conservation officer with the NT Government in Alice Springs, explains below how gullies can be avoided.
"If you go for a walk in any eroded area you will find the starting point of a gully (the initial nick point). Normally the cause is a fenceline or access track cut below natural surface level that has allowed water to drop down an incline, scour the base and cause a headwall to form, which continually collapses and moves upslope."   

So we need to be careful about leaving cuts in the landscape. Putting a grader blade deep into the soil is a common cause of scarps.

“A lot of people that maintain cleared fencelines with graders think they have to have a full blade of dirt, because otherwise they aren’t working their machine. But that approach can cause erosion. I think we would be better off sweeping the surface instead.

‘With sweeping you don’t get a full blade of dirt. You just sweep like a comb. The secret to sweeping is that you’ve gotta have the track established first without gouging. Scrape first them maintain by sweeping. And you need to maintain it. If you don’t maintain it and it becomes overgrown, the first thing you want to do is dig deep with the grader and get rid of all the shrubs. If you maintain regularly, all you need to do is sweep. Also, if you spread your load when driving along tracks, you are maintaining your fenceline with your vehicle and won’t need to use machinery as often.

“Location is another part of avoiding erosion. Fence to the terrain. Follow ridges and contours. If you do that you will reduce the need for maintenance.”
For more information click here and see links to technical notes and fact sheets. Also, you can order more detailed videos and manuals though the Victoria River District Conservation Association. To contact them, click here.

1 comment:

  1. This is really good! Many people think gullies form from too much flow, but this is not nearly as important as nickpoints because gullies eat their way into soil UPslope, not downslope.

    And major increases in woody plants like coolibahs and mulga tell you the system is already unplugged down slope somewhere. Go find the nick point?

    The problem with gully heads is that they aggressively dehydrate the landscape hinterland of both surface and in-ground water.

    Gullies are primarily water thieves. If you live in an arid environment, can you let them expand and get better at thieving?


Note: only a member of this blog may post a comment.