It makes sense to use what you have available locally before looking for water outside the Town. This is why Castle Rock Water has firmed up existing local water rights in Plum Creek that go back to the 1860s. We also have the opportunity in the near future to reuse the deep groundwater we pump from the Denver Basin aquifer. To use all of these local renewable water resources, we needed a special treatment facility.
Plum Creek Water Purification Facility
The Plum Creek Water Purification Facility (PCWPF) is Castle Rock Water's crowning jewel and one of the largest pieces in the Town's renewable water puzzle completed to date. The facility, along with our first access points to renewable surface water in Plum Creek, was completed in 2013, and expanded in 2017, for the capacity to treat all the water the Town needs on a typical winter day, up to 6 million gallons of renewable surface water or groundwater per day. Advanced Treatment processes were added in 2021 to purify multiple raw water sources to meet drinking water standards, including renewable indirect reuse water and direct reuse water. The Plum Creek diversion and pump station were completed in 2021 allowing Castle Rock Water access to the water rights and imported water within East Plum Creek.
Further planned improvements at the purification facility will expand capacity to 12 million gallons a day. These expansions are projected to take place over the course of the next several decades as needed to reach our long-term goal.
Alluvial well construction
As part of the Plum Creek Water Purification Facility project, six new alluvial wells were constructed along East Plum Creek. These wells supplement the Town's three existing alluvial wells by supplying renewable water for treatment.
The creek alluvium consists of sand layers that have been deposited by the stream channel over many years. Water is naturally stored in the pore spaces between the sand grains underground. These wells have been completed 50- to 60-feet deep in the saturated alluvium, tapping the subsurface aquifer that is then replenished by natural flows in East Plum Creek. Because the source of water is from surface runoff flowing into the creek, this water supply is considered renewable.
The fourteen alluvial wells provide anywhere from 10 to 20% of the Town's water supply needs depending on overall system demands. Water from these alluvial wells is also processed through the Plum Creek Water Purification Facility. The amount of water produced by the alluvial wells depends on a number of factors, including the efficiency of the wells, the amount of stream flows available for recharging the aquifer, and the priority of the Town's surface water rights.
Central Well Field
The Central Well Field consists of seven alluvial wells located in The Meadows development near East Plum Creek. As part of the Plum Creek Water Purification Facility project, seven well sites were identified for construction in two areas of the Central Well Field. The northern cluster of four wells near Atrium Drive were constructed in 2013 and 2014. The Plum Creek Alluvial Well Field Project constructed three alluvial wells in the Central Well Field, near the Meadows Parkway bridge.
Alluvial wells are simply defined as wells constructed in the alluvium deposits of a stream. Since the water source for the alluvial wells is an alluvial aquifer recharged, in this case by East Plum Creek, the wells are classified as a renewable water source.
A need for a sustainable long-term water supply was identified in the Town's Water Resources Strategic Master Plan. One of the major goals of that plan is to establish renewable, sustainable water supplies that account for 75% of the annual demand for water in Castle Rock by 2050.