Monday, August 15, 2016
Edie Adams, Marketing
The owners of RT Ranch — which is a self-supporting, off-grid custom home that generates its own electricity through solar power and propane generators — desired to supplement their electrical portfolio with hydroelectricity. The ranch is located four miles from the nearest county road on a private, unpaved road below the summit of Mount Sopris. It’s adjacent to United States Forest Service (USFS) land and does not have any nearby utilities, requiring a unique setup that is the largest residential off-grid power system in the state of Colorado.
Olsson Associates was initially contracted to evaluate the water delivery system at RT Ranch. The system diverts water from East Sopris Creek into a ditch for irrigation and two ponds. The ditch descended a steep slope and was continuously eroding the hillside, resulting in a high sediment load being delivered into the ponds. This sediment was being dredged from the ponds on a regular basis, and the ditch was not stabilizing. Given the existing conditions and the severity of the down cutting along the existing ditch alignment, Olsson designed a buried pipe system along with intake and energy dissipation structures to eliminate the erosion and reduce sediment deposition in the ponds.
The pipe system design included a headgate at the top of the slope to divert water into the buried pipeline (keeping the ditch available as a diversion option for pipe maintenance) and a concrete impact basin energy-dissipation structure at the outlet of the pipeline. The Olsson team adapted an existing headgate to be used as intake works for a hydroelectric penstock. The team also recommended upgrades to the existing turbine and electrical system to accommodate the new pipeline, which the client made.
Olsson also assisted in analyzing potential environmental impacts of the pipeline corridor. These impacts were minimal because of the timing of the project and the resilience of the local flora. After the pipeline was in place, the client tasked Olsson with providing electrical engineering services and working with other contractors to site and design a hydroelectric power plant at the terminus of the pipeline in order to take advantage of the alignment. Other design services provided by Olsson included:
Olsson also provided full turn-key environmental permitting and compliance services. Related to the hydroelectric project, Olsson’s environmental team developed a stream and wetland restoration plan to restore approximately 500 feet of a downcut and eroding stream and wetland complex. This plan included methods to stop the stream from continuing to downcut and to raise the area water table to support adjacent wetlands, strategically using dredged material from nearby ponds.
“It was great seeing a product evolve that was custom made for this unique situation, and it was great seeing the ranch staff and our electrical and water engineering teams engaged to make this happen,” says Eric Petterson, Olsson senior biologist.