voters in the TID and MID service areas and San Francisco approved bond issues to finance the construction of a new dam. The irrigation districts hoped to complete the dam by 1966, but concerns that the dam would further impact decreasing populations of king salmon in the Tuolumne put a temporary stop to the project. In fact, it was not until that year that the Federal Power Commission (now Federal Energy Regulatory Commission) licensed the irrigation districts to go ahead on New Don Pedro. The $49.7 million primary construction contract for the dam was awarded to Guy F. Atkinson Company on August 22, 1967. When he first saw the dam site, chief engineer John Goodier was reported to have said "[it'd be a] tough nut to crack". Clearing the dam site began immediately afterwards, in addition to the construction of access roads and a camp for construction workers. Construction of the dam's service spillway began a week later on August 29. On September 22, 1967, work began on the diversion tunnel that would allow the river to bypass the construction site. The tunnel was fully excavated by March 13 of the following year and lined with reinforced concrete by August. On September 7, a cofferdam was constructed and the diversion tunnel began to carry the flow of the Tuolumne. As the dam site dried out, the foundations were excavated down to bedrock; cracks in the rock were injected with so-called "dental concrete" to stabilize the foundation. Construction of the embankment began on September 16, 1968 using the hydraulic fill method. The dam's massive concrete emergency spillway was completed on January 19, 1969. However, severe flooding on January 26 destroyed the cofferdam and all of the construction site's bridges, putting work a month behind schedule. Cleanup proceeded at a rapid pace and placing of impervious material for the dam's core commenced on February 27. For the next fifteen months, a fleet of massive 125-ton (113 t) dump trucks delivered an almost constant stream of dirt and rock to the site, and the dam wall rose at an average rate of per day. The workforce peaked at 500 men in mid-1969 and on December 10, the service spillway was completed. On May 28, 1970, the embankment was finally topped out with the last of over 250,000 truckloads of material. After the clearing of over of the future reservoir site and the relocation