At any rate check out the new part of the website for the expansion Gross Reservoir, part of Denver Water’s Moffat Collection System. They write:
If approved, the project would produce 18,000 acre-feet of new supply by expanding an existing reservoir rather than building a new one. The current dam height would increase from 340 feet to approximately 465 feet. The proposed project would increase Gross Reservoir from its current storage capacity of 41,811 acre-feet to approximately 114,000 acre-feet – an increase of 72,000 acre-feet. (Denver Water has determined four acre-feet of storage are needed for every one acre-foot of supply.)
Because Gross Reservoir was originally designed to be this larger size, other facilities, such as the Moffat Tunnel and South Boulder Canal, do not need to be modified and no additional water rights are needed. The additional water would be carried through the existing Moffat Tunnel from the Fraser River basin and Williams Fork River basin in Grand County, as well as from South Boulder Creek basin. Streamflow in the Fraser and Williams Fork rivers and South Boulder Creek would only be decreased by this project during wet and average years during the runoff months.
Denver Water officials anticipate that the Corps of Engineers draft environmental impact statement for the project will be released in the next few weeks.