Parker's Reuter-Hess reservoir might quadruple in size if the Army Corps of Engineers approves an expansion proposal.
About three miles southwest of downtown Parker, the Reuter-Hess Reservoir originally was designed to provide the Parker Water and Sanitation District with about 16,000 acre-feet of water storage.
Construction is already under way, but now Castle Rock, and perhaps as many as four other water districts, also want to use the reservoir to store water.
If approved, the expanded reservoir will provide about 70,000 acre-feet of water storage.
Ron Redd, Castle Rock's utilities director, said it takes several years to find and develop storage solutions, so it made sense for Castle Rock to join a project already well on its way to completion.
The town gave Parker Water and Sanitation District $100,000 in earnest money, but that money will be returned if the Corps of Engineers doesn't approve the expansion.
"We're not guaranteed anything yet," Redd said.
Frank Jeager, district director for the Parker Water and Sanitation District, said the expansion would make Reuter-Hess about 300 surface acres larger than the Cherry Creek Reservoir.
Originally, the reservoir was expected to be completed by the end of 2007, Jeager said. If the expansion is approved, it probably won't be done until around 2010, Jeager said.
The approval process for expansion is a complicated one, Jeager said, because the U.S. Army Corps of Engineers has numerous requirements.
"They follow them to the letter, and that takes time," Jeager said.
When Jeager initiated the process to build the reservoir, some of the area's water district officials were skeptical he would get approval and therefore did not sign on as partners, Jeager said.
Now that the reservoir is becoming a reality, water district officials are more interested, Jeager said.
The reservoir is one of a handful of water projects under way in the south metro area, which relies heavily on nonrenewable underground water supplies.
Some experts have warned that those resources are being drained, so water district officials are trying to find other, renewable water sources.
The Army Corps of Engineers is also being asked to approve an expansion of Chatfield Reservoir. In addition, several water districts are participating in a pipeline project, which will carry water from the lower South Platte River as far as Castle Rock.