In 1948 SSJID and OID jointly founded the Tri-Dam Project. Tri-Dam had two functions: to increase water storage to meet irrigation obligations and to add hydropower production at a low cost and substantial benefit. Construction on the Tri-Dam reservoirs — Donnells, Beardsley and Tulloch — began in 1955 and became operational in just two years. The Tri-Dam Project was completed in 1957.