Control of hillside seepage in avocado and citrus orchards

Many of the citrus and avocado orchards near the foothills of Ventura and Orange counties are damaged by root disease and excessive wetness from hillside seepage. The damage is most severe during wet years or when the adjacent hills are excessively irrigated (see fig. 1). Dense subsoil and steep topographical conditions cause excess water from rain or irrigation to seep underground downslope creating a drainage problem (see fig. 2).