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PAWSD revises Dry Gulch raw water plan

On Oct. 27, the Pagosa Area Water and Sanitation District Board of Directors approved a revised approach to diverting raw water from the San Juan River to the proposed Dry Gulch Reservoir project.

According to engineers, the modified plan will reduce water treatment costs while meeting current and short-term future demands, preserve senior West Fork water rights and allow incremental system development as needed.

The change departs from a January 2008 recommendation, which suggested constructing new pumping and treatment plants on the river at the Dry Gulch site two miles northeast of town, then abandoning the existing (and aging) Snowball pipeline and treatment plant.

District board members say the new plan, known as Option 6A, reflects the necessary and inevitable evolution characteristic of any long-term project. They contend, as ongoing engineering studies are completed, updated information often points to more efficient, less expensive alternatives to original plans.

While the preferred January 2008 proposal — referred to as Option 6 — would also upgrade a “treated-water” pipeline from the Snowball plant to a standing storage tank near the Hilltop Cemetery, Option 6A will require a new treated-water pipeline from Dry Gulch to the cemetery tank.

Option 6A is the latest alternative to the January 2008 list of proposals describing various methods of providing potable water to District Two, or the downtown portion of PAWSD, until Dry Gulch becomes a reality. While the plan would cost about the same as either of the original options 5 and 6, it is actually a combination of the two. Current projections put the total cost at $28.5 million, with an annual cost of around $2.2 million.

As designed, Option 6A involves reconstruction of the Snowball pipeline from the West Fork diversion to a proposed treatment plant at Dry Gulch. Until development of the Dry Gulch plant is necessary, the Snowball treatment plant will be upgraded and expanded, while a segment of the Snowball pipeline (leading to the Snowball plant) is maintained. As the Dry Gulch plant is eventually built, workers will connect both plants with a new pipeline, and construct the pipeline from Dry Gulch to the cemetery tank.

Meanwhile, as engineers further scrutinized the original options, they also realized that the quality of water coming from the West Fork was notably superior to that found in the main stem of the San Juan. By continuing to utilize West Fork water, PAWSD could reduce projected water purification costs, while maintaining stringent water quality requirements.

Also, because the elevation of the West Fork diversion is hundreds of feet higher than the proposed Dry Gulch treatment plant, it will naturally pressurize the plant, thereby reducing the cost of building and operating expensive pumps.

Too, building a new diversion at the Dry Gulch site would require transfer of the Snowball water rights from the West Fork to the main stem, through a Colorado Water Conservation Board in-stream flow water right. Based on discussions with the CWCB, doing so would likely result in subordinating the Snowball rights to the CWCB right, thus removing them from priority much of the year. The end result would be a less-than-firm water supply for District Two.

According to PAWSD, Option 6A will allow system development in stages, as funding and demand dictates. An upgraded Snowball treatment plant and a newly-aligned Snowball pipeline segment around the Jackson Mountain slide area would come first, with an upgraded stretch between the slide area and the West Fork diversion next. Eventually, as the Dry Gulch treatment plant is built, an extended line would connect it and the Snowball treatment plant.

As always, PAWSD insists it will only develop whatever raw water storage and distribution systems it can afford, as area demand identifies the need. In the meantime, engineers will continue to fine-tune plans, with hope of improving efficiency and cutting costs.

Time will tell.

chuck@pagosasun.com