THORNTON — The city of Thornton is in the first stages of a two-year redevelopment project that will turn the West Sprat Reservoir into a raw water storage facility, effectively consolidating all the city’s water runoff resources.
The reservoir will be closed to public starting at the end of September, ending fishing season a few weeks early this year.
The South Platte regional trail will also be diverted (and elongated three times its normal route) around the construction area until the reopening in fall 2015.
“We’ve wanted to do this project for about 15 years — basically since the city acquired the reservoirs back in the late ’90s,” said Emily Hunt, Thornton water resources manager.
Hunt said that including West Sprat, the city owns a string of about nine reservoirs along the South Platte River near 100th Avenue and McKay Road. The problem is, none of the flooded gravel pits feed into one another, mainly because of the design of the middle reservoir — West Sprat.
“The ultimate objective is to get (the reservoirs) to be all interconnected and operate like one big storage bucket,” Hunt said. “The project is going to allow … that string of reservoirs to operate much more efficiently.”
Cost projections for the development are $12 million, said project manager Eduardo Moreno. It will be completed in three phases, starting with the nine-month construction of a slurry wall to isolate West Sprat from groundwater that the city does not have the rights to use.
Moreno and his team will move all the fish to other reservoirs and drain the water from West Sprat during phase two.
The final stage includes all improvements and additions to the facility — the construction of a spillway between the South Platte River and the reservoir, piping to join all nine reservoirs and brand new fishing piers. The fish will be returned home, and the regional trail will be set back to normal at this time.
The overall expansion of the reservoir required the acquisition of property easements along the perimeter of the grounds. Moreno said the city successfully gained five permanent easements in Adams County prior to starting construction.
“Right now, we need to make some additions to our water supply system in order to keep up with demand. We have to stay ahead of the growth curve,” Hunt said. “We’ve had it in the books for awhile and this is the year that we are bringing it online.”
Megan Mitchell: 303-954-2650, or mmitchell@denverpost.com
