Does anyone have ideas on using on contour swales/berms and brush dams to slow down water while building up large gully? Area is about 100' across, 15' deep in the center at head, and perhaps 200' long head to tail. It's below a larger hill with a 10' retaining wall made of ties, which has a 2' wall below.
Eventually the wall is going to go. Thought is that the swales with berms down hill will help spread water out to prevent gully from getting deeper, large brush dams would capture organic material in center where water moves fastest. Both together will allow me to build up the soil.
If there wasn't the retaining wall (and my house) above it, this would make a perfect pond.
Key would be to spread out water from surrounding hill sides too by extending swales on contour to stop gully from getting deeper. There is a thin forest canopy with about 4 hours of light during the day, so I may be grow herbs, berries, and lettuce in that area. One hillside has a good supply of puffball mushrooms. Already started on trench and berm up the watershed to reduce how much water gets down there.
Contractors suggest several large rock walls in wire baskets (gabions) built then filled in between to terrace. No prices were mentioned, but I'm sure I'll need to budget that kind of infrastructure. What have been your experiences? Any suggestions because it will take a lot of leaves to fill it.
We have two large gullies/arroyos on our place and are slowly trying to repair them with brush dams. Brush dams and various rock structures are a gradual way to fill the channel with silt. It may also be advantageous to work on repairing the watershed that feeds the gully.
Many different strategies are detailed in Brad Lancaster's book "Rainwater Harvesting for Drylands Volume 2"
Great links and useful information. I'm using wicker-weirs (didn't know they were called that) on banks in watershed area up hill with leaves packed behind them. Also brush dams between house and garage which has improved the channel forming there. On-off contour swales on another area of watershed.
Looks like I could continue those types of things in deep of gully but add beds in front of them for berry bushes once sediment starts building, shade tolerant cover cropping till then. Couple of those links had combinations of structure and brush growth.
My original plan had on contour level trench/berm to spread water out but may want to straw bale on contour head cut or use mulch bags like the one-rock dam on them to build up the hill side. These would be in multiple rows every starting from the top because slope is low.
I'm currently reading "Mycelium Running" by Paul Stamets, incorporating burlap bags full of inoculated shredded hardwood may add some exciting flavor to this project. I can build up brush fences on these contour walls, later turning them into beds when enough material can be accumulated.
More watershed work happening on orchard side, rain water collection to reduce what comes from the house, and garden beds up hill to slow/use up that water. May invest in a professional or structural engineer to look at the situation so I know where the retaining wall stands (or doesn't.)
Will try to get my hands on Brad Lancaster's book -- his videos are great. Thanks for the resources.
Ever considered planting a willow tree or two at the gully?
"DAVID HOLMGREN: We've got a situation where large amounts of public money are being spent with no full evaluation of the environmental impact and the benefits.
TIM LEE: Holmgren, the co-originator of the permaculture movement, argues that willows help restore degraded waterways by filtering out pollution and trapping sediment. For 25 years he has studied his local creek, once badly degraded by goldmining. Now it mostly carries stormwater and urban runoff from the central Victorian towns of Hepburn and Daylesford.
DAVID HOLMGREN: That growth of blackberries and, most strongly, the willows have captured so much sediment, we're actually standing on a beautiful alluvial loam captured by the willow trees from upstream erosion, essentially. This, what I'm standing on here that looks like a rock shelf is actually a willow root mat and it's composed of all the fibrous roots of the willow which feeds from the water, and it's full of sediment that the willow root mat has captured. It's also incredibly efficient at stripping dissolved nutrients out of the water that would otherwise be pollution and absorbing that into the biomass of the tree.
TIM LEE: Holmgren's study showed the drop of nutrients from deciduous willow leaves is similar to that of a native forest, and he argues the willow's dense canopies curb other pest plants such as blackberries. "
Excellent idea, I'm looking at using gabion baskets to retain deep area beyond retention wall. Could just as easily have a cavity built for a root clear around a steel frame.
Been playing around with growing mushrooms. Might even have enough space for a mushroom cave if I can find a professional engineer to get out here to help me with the design. At least there is room for a root cellar.
The only challenge with planting willows is that they won't keep my house from sliding down the hill if the current retention wall made of wood ties fails.
I did follow Tyler's idea with slowing down the problem with brush dams. I could plant willows near the check damns I'm planning for a creek far behind the house later.
It turns out willows are easy to propagate so I'll get my hands on some from cuttings down the street this coming June when they trim the one hanging near the road.
You are right, mushrooms do need light. So now I have an excuse to have power down there. More likely it would only be used when mycelium is just getting started (rather than my basement) and for root cellar. Might have to go on my long term plans list because the more I think about it, the more it might cost.
At least till then I've been building brush wattle on contour and brush dams in troubled areas. Will be using James' idea about willows towards stream in back and on sides. Will do rows of Jerusalem Artichoke, Comfrey, Blackberry, and Blueberry as I can get the soil built up outside where a retaining wall might go.
So far brush structures have cleaned things up a bit. At least they are holding the piles of leaves I've spread out there for beds.