Rocky Mountain News
Colorado to double water supply
By Mike Patty, Rocky Mountain News
In the coming months, Aurora officials will choose a plan designed to bring another 80,000 acre-feet of water into its system, doubling the city's supply by the year 2050.
One proposal under study, the Lower South Platte Project, would be among the largest public works projects ever undertaken by Aurora."We are looking at several alternative projects - expanding our groundwater system, developing conditional water rights we have for more transmountain diversion, more leasing, another water reuse treatment plant and the Lower South Platte Project," said Peter Binney, Aurora director of utilities. "These aren't singular projects that are mutually exclusive. Ultimately, the city will do all of them."
The most costly and ambitious of the alternatives is the Lower South Platte Project. If approved, the project would remove water downstream near Brighton and pump it back to Aurora via a 35-mile pipeline to a newly built reservoir. There the water would be treated and reused.
The project could cost between $250 million and $650 million.
Without the pipeline, the water would continue downstream and be lost to the city.
Under Colorado law, water native to a basin is usually used once, treated and returned to the stream. But water transferred from another watershed basin may be reused until it is gone.
About half of Aurora's water supply comes from the Colorado and Arkansas river basins through transmountain diversion.
That water can be be reused again and again, minus calculated losses from evaporation and seepage, if it can be retrieved, stored and eventually pumped back upstream.
"The majority of the South Platte water in our system could be used to extinction," Binney said. "So the beauty of the Lower South Platte Project is it allows us to fully reclaim water we already have and make multiple uses of it."
Last year, Aurora filed a request with the State Water Court to store the water. A ruling by the court isn't expected until next summer.
If approved, the project would be built in phases. The first would return 10,000 acre-feet of water by 2009. The next phase would make available a total of 15,000 acre-feet by 2012.
An acre-foot is roughly 326,000 gallons of water, enough to supply two households for a year.
Those goals can be met without the city having to secure additional water rights.
Eleven alternatives have been selected from a group of 30 for further study. They include various combinations of ditches and canals, gravel pits, pumping stations, pipeline and storage facilities.
Those 11 alternatives will be narrowed to two by August and to one by November.
The utilities department has identified 2,700 acres east of Aurora Reservoir as the preferred site for a 44,000 acre-foot terminal reservoir for the South Platte Project.
"We will be talking with State Land Board officials over the next 60 days to see if there is the potential to move forward," Binney said.
Aurora also is negotiating with other entities, including Douglas County, the East Cherry Creek Valley Water and Sanitation District, and the United Water and Sanitation District about cooperating on the project.
Whatever plan is chosen, construction would be paid for by both current and future water users and those developing land in Aurora.
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