- Geotechnical investigations
- Embankment design
- Spillway design
- Outlet works design
- Water conveyance pipeline design
- Water controls gates and valves
- Environmental permitting support
- Value engineering
- Construction documents
- Emergency Action Plan
- Resident engineering
- Constructions administration services
- Post-construction services
RJH was retained by Parker Water & Sanitation District (PWSD) to provide engineering and construction services for the largest dam (non-federal) to be constructed in Colorado in the last 30 years.
The initial dam (Phase 1) was designed to be 135 feet tall and impound 16,200 acre-feet (ac-ft). The project was intended to include an enlargement phase (Phase 2) several years in the future, in which the dam would be modified to a height of 196 feet and capable of storing 72,000 ac-ft. During Phase 1 construction and, due to looming storage demand from nearby communities, PWSD elected to modify the original design to accommodate the near-term enlargement and avoid building components, such as spillways and terminal facilities, that would no longer be needed after enlargement.
RJH staff led design of the dam, outlet works, emergency spillway, and other ancillary facilities. The engineering team worked closely with the Colorado Office of the State Engineer to obtain authorization to implement the significant design changes required for Phase 2 while construction of the Phase 1 design was in progress.
Final components of the project include a 14 million cubic yard, zoned earth embankment with a sloping clay core and sand filter, and soil-cement upstream slope protection; a multi-chamber intake tower with two 78- by 78-inch water control gates, five 48- by 48-inch water control gates, 78-inch-diameter outlet conduits, and an integral service spillway capable of passing the 100-year flood; an auxiliary spillway with a five-cycle reinforced concrete labyrinth weir, soil-cement approach and discharge aprons, and an unlined earthen discharge channel; and instrumentation and monitoring equipment.
The Phase 2 enlargement required raising the intake tower by 65 feet, extending the downstream conduits, construction of the terminal facilities, construction of an access bridge from the dam to the tower, construction of a 48-inch-diameter pipeline to a future water treatment plant, and construction of the auxiliary spillway.
RJH provided construction engineering services for both Phase 1 and Phase 2. This work included bidding and procurement services, field engineering by a team of six engineers and geologist, documenting and reporting on the contractors’ work, and performing contract administration.