ZARZAMORA CREEK. Zarzamora (Salsamora) Creek rises in northwest San Antonio in northern Bexar County (at 29° 31' N, 98° 34' W) and runs southeast for eight miles, through the western portion of the city to its mouth on San Pedro Creek, two miles west of downtown (at 29° 26' N, 98° 33' W). It traverses rolling terrain surfaced by clay loam soil that supports mesquite, live oak, and grasses.