Of you have no trees and bushes; just barren ground, cover the bare soil with a tarp when it rains next.
Get busy planting new ground cover. Grasses grow fast, but they have shallow roots. Plant yew trees, mint, salal, sdogwood, creosote bush, etc.
School was 15 years ago and I don't remember all the scrub in the California chapparral ecosystem. Not my state.