Engineering:

Cost of constructing new bypass tunnels?

Let’s look at the cost of original bypass tunnels:

1955-1957 Cost Estimate:

• Diversion tunnels were 41 feet in diameter
• Right diversion tunnel was 2,749 feet long
• Left diversion tunnel was 3,011 feet long
• Total length would be 5,760 feet or 1.09 miles

“Excavation, in all classes, in open cut for diversion tunnels” – $950,370.00 (removal of 316,790.0 cubic yards of material)

“Excavation, all classes, in diversion tunnels” – $3,731,938.20 (removal of 186,596.91 cubic yards of material)

• 1957 USD =====> 2019 USD (1 to 9)
• $950,370.00 ====> $8,553,330
• $3,731,938.20 ===> $33,587,443.80

Total estimated excavation cost = $42,140,773 (in 2019 dollars)- without any mobilization cost. If we assume mobilization costs will double the estimate, the total would be $84,281,547

Cost of similar modern projects:

SNWA “Third Straw”: 24′ in diameter, 3 miles,

for $817 million, or $272 million per mile.

Ballpark average for tunneling projects in California:

30′ tunnel costing $20,000 per foot drilled, or $84.4 million per mile.

Rough Estimated Cost of Drilling New Bypass Tunnels around Glen Canyon Dam:

$80 – $275 million dollars