I am getting 35 cement blocks from freecycle and I was thinking about using them to edge my herb garden (plan changed). I was going to bury them about 1/4 way deep all around bed and then fill holes with potting soil and plant something non-invasive and drape-y in the blocks (I was thinking moss rose) to have a pretty and solid border.

I'm using up some of the old bricks on my property, but most of my runoff problems are 'divert to the street' kind of things.

I'd say lay a drain (a ditch full of stones) at the fence line- but in clay soil, that's no small task at all.

Hay bales are a little much- but 'slices' of one laid on their side can be seeded and/or covered with mulch or compost- the wide footprint seems to do a good job of redirecting the water.