Here is an interesting photo of the diversion tunnel at El Capitan Dam. In 1932 Tom Connelly and Wilhelm Rohl formed the Rohl-Connolly Company to bid on the construction of El Capitan Dam. After successfully winning the contract, the new joint venture completed the project in 1934. After that, the El Capitan Reservoir was created and connected to the City's water system via the El Capitan Pipeline. Located approximately 30 miles northeast of San Diego on the San Diego River, it has the largest capacity in the City's reservoir system.