Several years ago I bought a split level home overlooking a lake on a steep hillside in Northwest Arkansas. The only access to the lake was via 114 rotten wooden steps. Attempting to walk down the hillside without the steps was next to impossible due to the grade. The soil was white, powdery, and full of limestone rock. Between the soil quality and the needles from several pine trees, nothing grew outside of some stunted bushes.
Things were OK until I cut down all of the trees and removed the steps to open up the view. After doing that I ran into a erosion problem. Bad enough that after a particularly heavy rain storm I found a newly formed ditch a couple of feet deep. After a lot of trials and errors that involved bringing in several square yards of dirt to fix, I’ve finally hit upon some methods that work.
Trials and Errors
Surprisingly the Internet isn’t a good resource for erosion control. Most of what I could find related to erosion control in desert environments, such as southern California, or temporary control related to construction run off. Neither of which would help me build a permanent solution in my humid subtropical northwest Arkansas home that receives sixty inches of rain a year.
Spreading hay: In theory if you spread hay over bare dirt with some seed laid down the hay will hold in moisture, stop the rain from washing everything away, and keep birds away from the seeds. Three years after spreading hay I still find it random places. To say its messy is an understatement. The first windy day will spread your hay to every nook and cranny around. On a steep hill rain will wash the hay away along with whatever is under it.
Planting grass: During the first fall I planted some winter rye grass. As far as erosion control it worked pretty well. It grew quickly and held the dirt down well. The problem with grass is that it grows tall. You either have to mow it or knock it down with a string trimmer. Mowing on a steep hill side sits somewhere between pain in the ass and impossible.
Gravel: If you lay down a couple inch thick layer of 3-4 inch gravel, erosion stops. This works, but I don’t like the way it looks. I want some green.
Concrete: I had a concrete walking path built. It only served to stop the water in places it shouldn’t, and then speed up the water everywhere else. I wish I could jackhammer the whole thing up and get rid of it.
Control water at the top of the hill so you don’t have to worry about it at the bottom: I built two large drains that collect all of the water at the start of the slope and carry it all the way down to the lake, bypassing my backyard entirely. This stopped the majority of the problem all by itself. Once the drains were built the only water I had to deal with is what actually fell in the backyard. These drains were both hand dug, no way to get machinery where I needed it because of the slope.
Swales: The best way I can describe a swale is a drainage ditch that doesn’t go anywhere. You dig a ditch that is level to the grade. It fills up with water and holds it there until it naturally percolates down into the soil below.
Walking Trails: I had a zig zag of walking tails built down the slope. It took about a day for a guy with a small skid loader to do the job. The trails are covered in compost. The grade of the trails is slight enough and the compost absorbent enough that they act like swales.
Clover and Vetch: Clover and vetch are two low growing legumes. Clover looks just like you think. Vetch looks something like a fern. Both plants fix nitrogen into the soil improving the quality. Both look nice, stay green all year, have pretty flowers most of the summer, and grow low enough you never have to mow. Animals love it, I have deer, rabbits, and geese that hang out all day. Use white clover, other clover species can get tall.
Compost, compost everywhere: The city I live in sells compost by the yard so cheaply they almost give it away. Originally I used the compost to cover the walking paths I built down to the lake. Pretty quickly grass began to grow on the paths. It grew so well that I couldn’t keep it knocked down. I then ran with the idea and put down compost everywhere. I raked the soil a bit, dropped the clover and vetch seed, and then spread compost. Wash, rinse, repeat, for the entire back yard.
In my opinion what really worked to control erosion were three things, use drains/trenches to control water at the top of the hill, cover any bare dirt with compost, seed heavily with clover and vetch.