Prairie Waters Pipeline Relocation

Challenge: Built in 2010, the Prairie Waters Pipeline (PWP) was designed to be an indirect potable reuse system. It delivers 10 MGD of raw water from the South Platte River, pumping the water 34 miles south, with a 1000-ft elevation gain, toward the Peter D. Binney Water Purification Facility. The alignment of the PWP parallels E-470, the major loop corridor, one of the hottest development corridors in the Denver Metro area. Development within the corridor required additional interchanges that would disrupt the current alignment of the PWP.

The 60” steel PWP required an approximate ½ mile realignment for the future interchange to accommodate the proposed bridge structure and highway access ramps. Directly adjacent to this section of the PWP, three major residential and commercial developments were in planning or construction. The section of the relocated PWP was going to cross a FEMA floodplain, where the Tributary T drainage way and regional pedestrian trail were also being relocated to make room for the interchange. The relocation of the PWP impacted two Jurisdictions and three Districts. Design development occurred during COVID, affecting the schedule of critical supply chain components necessary for the system.

Solution: By working closely with the City of Aurora to determine an alignment that was hydraulically feasible, accessible, and that could be constructed during the shutdown season, as well as allowing for a future parallel line, we were then able to put the plan in action and coordinate with surrounding stakeholders. HR Green began by working with the funding district, AARTA, to coordinate 16 stakeholders and engineers whom the relocation would directly impact.

The early stages of coordination consisted of working with the overseeing engineer for the PWP system and the interchange engineer to develop a horizontal and vertical alignment that would not impact the overall water model. Once the general alignment was determined, intense coordination commenced to bring all the parties together for a solution that would not impact their individual interests. Bringing on the contractor in the early stages provided insight into construction feasibility and put solidifying material for construction into motion. Lead times for the steel pipe ballooned from 12 weeks to 20 weeks during the COVID period.

The design was expedited so that the parallel line could be constructed by spring and tested before the one-month shutdown period and final tie-ins could be achieved. HR Green and AARTA worked together to finalize land acquisition areas and required temporary easements with the adjacent property owners and the ultimate multi-use easement necessary for the PWP.

HR Green and JHL (contractor) worked closely during the final stages of design and into construction, coordinating final trail locations, floodplain crossing stabilization methods, fiber line communication routing, corrosion protection, embankment stockpiling, pipe casing installations for a future road crossing, field changes due to unforeseen conditions and revegetation in time for the interchange to start construction.

Benefit: The PWP is a main contributor to one of two treatment trains at the Binney Water Purification Facility, directly providing safe, reliable drinking water for the citizens of Aurora that it serves with its 50MGD capacity. Rerouting the PWP provides Aurora direct access to manways, butterfly valves and communication to safely maintain the system, ensuring constant reliability.

In addition, when maintenance is required on the PWP, disruptions to residents and commercial commerce along the E-470 corridor will be eliminated. The complexities of this project exemplified HR Green’s ability to foster communication between jurisdictions, collaborate with other engineers, and work with the construction team to create a successful project.