Knowledge about optimizing use of rain water under different systems is crucial for overcoming water stress and maximizing crop yield. In this regard, rain-water harvesting is one option that increases the amount of water per unit cropping area, reduces drought, and enables use of run-off. In this study, the importance of filters in rainwater catchment systems for increasing crop yields on steep lands of Khosbijan Natural Resources Research Station was investigated. Rain Water Catchment (RWC) systems with two treatments including: eliminating vegetation and pebble with a gravel filter, and eliminating vegetation and pebble without a gravel filter were created in almond seedling pits. Each year collar diameter, height, and canopy cover were measured at the end of the growing season. The results showed that over a three-year period, the changes in collar diameter, height and canopy cover were greater for filter treated plants. In other words, the presence of filters increased soil moisture storage in the root zone of the plant.