Jtd, if you are experiencing a lot of erosion, you may want to look into straw wattles (I believe that was what they were called). If you are not familiar with them, they are sort of like very skinny, burlap-wrapped, straw-type (maybe with a polymer?) bales or sausages that are about 8-12" in diameter and I think that the ones that we purchased were 50 feet long. You run them perpendicular to the runoff and they prevent the soil from slipping or cutting. They also help absorb a lot of the runoff and slow down the rest. They decompose over several years so you have protection long enough to get some type of binder planted if needed. The downside is that they do need to be staked in and, if I recall correctly, they are heavy. We used them on our hillside while waiting for the landscape to fill in and they worked well - effectively stopping the erosion until the ground cover, shrubs, tress, etc. could take hold. Because the hill is quite steep in areas and our area prohibits run-off onto community-owned trails, we also had a french drain installed at the very bottom of the hill that absorbed all of the remaining runoff. I believe that there are now mats that can be purchased which do much of the same thing.
