The hydroecology of selected vegetative species in the Tierra del Sol watershed, in San Diego County, California, will be studied. The selected species are blue elderberry (Sambucus Mexicana) and red shank (Adenostoma sparsifolium). The Tierra del Sol watershed is a 2.75 square-mile watershed located immediately north of the U.S.-Mexican border in the San Diego backcountry. The Tierra del Sol watershed features many vegetative lineaments, which are an indication of the presence of rock fractures. Specimens of blue elderberry and red shank are significantly represented along these lineaments. The study will seek to explain the peculiar alignment of these specimens in terms of a sustained moisture source. While the hydroecologies of blue elderberry and red shank are known from a conceptual standpoint, no studies have been found which document the seasonal variations of moisture at the root level. Thus, this study will be the first to connect the water affinities of blue elderberry and red shank to the presence of a sustained moisture source attributable to the rock fractures. Soil moisture measurements will be taken at each of twelve (12) sites, twice a month, for a period of 18 months. The findings will seek to support the hypothesis that the study sites have a sustained moisture source, which being fed from groundwater, is weakly dependent on the season. On the other hand, the control site will rely only on rainfed soil moisture and, thus, be strongly dependent on the season.