Sunday, December 15, 2019

Reworking a downspout after drainpipe clog

In 2005, I lined the gully from the outflow
 pipe with rocks to stop the erosion. 

Handling stormwater

When we moved into tour house in 2004, the downspout off our back porch was attached to a flexible 20-foot long drainpipe that had been buried. The stormwater was released onto a slope in the woods. This house was about 2 years old when we moved in and during that time, the stormwater had caused significant erosion in the woods.

Since this wooded area is a shallow ravine which serves to drain our front pond back into the lake. Eroded soil washing into this ravine could be carried into the lake during heavy storms, so I wanted to reduce the erosion.

My solution was to fill in the large hole right under the pipe and to line the gully with rocks. I wrote about this project in my first rain garden article: Rain lilies for my rain gardens.

The new configuration of the downspout.

15 year later...

The drainpipe had become totally clogged with tree roots. During heavy rainstorms the water backed up and created a burbling fountain at the point where the downspout connected to the underground drainpipe. It was so forceful that it sprayed water onto the porch. 

It was time to rework that arrangement. We separated the downspout from the underground pipe, cut off the top of the plastic drainpipe, and mashed the remainder into the ground. We had several plastic drainage trays to direct the flow away from the house. I made sure that the tray was tilted away from the house and used some of those fake river rocks to protect the soil under the lip of the tray.
I dug a slight swale and built a low berm to direct the water into the ferns.
I dug a shallow swale that sloped away from the house and built a gentle berm so the areas could be easily mowed. I also replanted the grass in the bottom of the swale and over the top of the berm. At this point, the ferns were higher than my swale, so I dug out a wide hole so that stormwater would drain into the wooded area and not back up around the house. I transplanted those ferns, which are netted chain ferns (Woodwardia areolata), to either side of the downspout and planted some other low-growing plants such as elephants foot (Elephantopus elatus).Then I covered the hole in the woods with woodchips.

Looking across the short span of lawn. 
I've watched how this new arrangement works during a couple of heavy rains, and as planned, the stormwater disappears into the woods.

Oh, and all those fake river rocks I'd used to line that gully... Most are still there, but buried deep in 15 year's worth of roots and soil build up. I should probably dig them up to use for another project and smooth out that gully now that it's no longer a drainage ditch.

Now that winter is upon us, I hope you're working on some projects around your landscape.

Green Gardening Matters,
Ginny Stibolt

No comments:

Post a Comment