Dicromantispa interrupta

Dicromantispa interrupta

Tuesday, June 16, 2015

From Ditch to Creek

I previously posted two reports about erosion control measures taken on my North Carolina house lot driveway. One was to this blog on September 12, 2010, about the stream crossing culvert (tinyurl.com/pt82u5r) and the other to my On Rappel blog on October 29, 2013, about the driveway ditch efforts (tinyurl.com/omgb8ve). The goals were to control erosion while simultaneously creating potential landscaping water features. I really won’t have time to do any serious landscaping until the house is built, but my efforts seem to have paid off. I hope this is apparent in the following before-and-after photos.

This is what the stream culvert crossing looks like now:

But this is what it started out looking like:

Ugly! You can see a lot of dirt exposed, with stream banks cut nearly vertical. I used a shovel to “bevel” the sides a little by removing the loose dirt and taking the overhanging root mat back away from the stream a foot or so on each side to reduce erosion. (Incidentally, there were a couple of ringneck snakes in the undersides of the root mat). I then placed small logs along both banks in the hope that not only would they retard the tendency to wash out the culvert but also provide a substrate upon which ferns, mosses, liverworts, and other plants could take root in and armor the ground:

The idea was that plants would grow on and between the rotting logs and form a web of roots extending back into the creek bank dirt. Indeed, the first photo shows that the plants readily took root in the logs.

Driveway ditch erosion was of equal concern, and since the driveway runs straight up the hill, so do its flanking ditches. This is part of the west ditch right after I added short split logs to create riffles and pools (and after a rain):

And this is what it looks like today:

You cannot hardly even see the ditch anymore, as it has silted in and the split logs are completely buried. Much of the initial storm water now sinks into the grassy, sediments in and beside the ditch, and what does runs off will sheet flow until reaching an open-top culvert (bottom of photo).

This is the east ditch right after construction:

After several years of vegetative growth, the east ditch looks even better. It gets more runoff than the west ditch, which keeps silt from clogging the ditch, although leaf litter sometimes has to be cleaned out as is evident in the foreground:

Overall, I’m pretty happy with the results. 

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