You're absolutely right, it's not exactly $10 billion. The upper range estimate by the State of California Department of Water Resources and Department of Parks and Recreation is $9,824,000,000.00. San Francisco Public Utilities Commission rounded their estimate to $9,000,000,000.00.
Well, not exactly. The 9.8 Bil was not the estimate, it was the upper limit of the range of the State's estimate, which was 2.9 to 9.8 billion. And that btw was the highest of the three estimates the PUC looked at which actually started at half a billion. But the PUC essentially accepted the State estimate as the most complete. It established a range, not a single estimate, based on the following (quoted from the page on which the PUC's assessment appears)
"Without any defined project objectives, any cost estimate is conceptual at best. Different concepts of what the project should be lead to different estimates of cost. For example, an objective of draining the reservoir and leaving the dam in place would provide for a much lower cost than an objective to completely remove the dam. Therefore, the cost estimates provided in previous studies are not directly comparable due to the lack of defined and consistent objectives.""Conceptual at best". I like that. Much more polite than the expression I used, but the point is the same.
Defined and consistent objectives, BTW means formulating a plan, which is certainly NOT any path that has been walked before.
