Old Padre Dam / Old Mission Dam in a dry state in 1937. The dam is a national historic landmark located along Father Junipero Serra Trail in Mission Trails Regional Park. To solve a water shortage after a drought, construction began in 1803 by Spanish colonists and Kumeyaay Nation converts from Mission San Diego de Alcala, founded in 1769 by Fr. Serra, the first of 21 California missions. The dam's five-mile-long aqueduct provided the mission with water. It was the first major irrigation project on the Pacific coast. (Photo by Hammond)