I had a very steep hill that the previous owners had almost completely cut down, but for a very few evergreen trees. I made brush rows on contour, and filled them in over time with weeds, chicken poop, grass clippings, wood chips, etc. (Hauling wood chips up that hill became too exhausting once the summer heat arrived.). This slowed the water considerably. I also planted deep-taproot plants, including comfrey and dandelion. It was hard to keep the comfrey alive for a year or two, but then it took off. I encouraged the black raspberries and other "weedy" plants. I also planted wildflowers, including lupine, obedient plant, Black-eyed Susan, and a lot of red clover. New trees began to sprout, and the plant life filled out.
I didn't have the problem of litter and broken glass. My chickens spent time up there dust-bathing, to my distress! But it kind of terraced a little section.
I was back there two years later, and it was a lovely hill! You can't really see the rows of brush unless you're hunting for them, and the whole hill is covered in plants and small trees. The comfrey looks good!