Water Resources Project Profiles

Dam Design & Rehabilitation

New Dam Design and Construction

New Cache La Poudre Irrigating Company, Weld County, Colorado

Engineering Analytics staff designed the Cornish Plains Reservoir to help The New Cache La Poudre Irrigating Company better control their down system water needs. The new zoned earth embankment dam is used as a storage and augmentation reservoir with a storage capacity of 3,500 acre-feet. EA staff completed the geotechnical investigation, material testing, design report, construction drawings, construction specifications, and construction permits as required by the Colorado State Engineer. EA staff also prepared all bid documents, coordinated the construction contract with the selected contractor, conducted the construction oversight, and certified that construction was completed to the construction specifications.

Existing Dam Rehabilitation

Henrylyn Irrigation District, Weld County, Colorado

Engineering Analytics managed the rehabilitation of Prospect Reservoir Dam. Prospect Reservoir Dam is a 45 foot tall earthfill dam that impounds approximately 6,500 acre-feet of water. Upon investigation, EA determined that the dam face and outlet conduit were significantly deteriorated and required repair. EA staff conducted a feasibility study to determine the most cost efficient repair methods and provided all geotechnical investigations, hydrologic and hydraulic analysis, structural calculations, bid and construction drawings, specifications, and contract documents for the project. EA bid the project for the owner and provided all resident project inspection, QC testing, and contract administration during construction.

Demolition and Repair

Sanchez Ditch & Reservoir Company, Costilla County, Colorado

Located near the town of San Luis, Colorado Sanchez reservoir dam is a 135-ft high earthfill dam which impounds 110,000 acre-feet of water.  Engineering Analytics staff have worked on this dam from 1992 through 2014.  The outlet control gates in the gate tower were rehabilitated in 1997.  Some gates were repaired, some replaced, and a new cone valve was installed at the bottom of the tower to regulate discharges.  A new gate control system was also designed and implemented that allowed remote control of the system which can only be accessed by a gondola.  The third phase began with a structural investigation of the outlet tunnel and tower.  Our team concluded that in order to maintain the serviceability of the tower and outlet tunnel, modifications to the tower were needed and the tunnel would need to be reinforced with rebar and shotcrete.  The repairs included removing the top 100-ft of the tower, installing a new gate control slab with hydraulically operated gates at the lower tower level, and lining the 8-ft x 10-ft outlet conduit with concrete and shotcrete.

Existing Dam Rehabilitation

Highland Ditch Company, Boulder, Colorado

Foothills Reservoir impounds approximately 5,000 acre-feet of water and has a dam height of 60 feet. The dam had been under restriction by the State Engineer due to excessive seepage through the dam embankment and due to an inadequate spillway. Engineering Analytics conducted the Feasibility Study required to obtain funding for the rehabilitation through the Colorado Water Conservation Board; provided all geotechnical investigations and design; and conducted all hydrologic and hydraulic analysis required for the design of the spillway. EA also provided all construction drawings, specifications, and contract documents for the project and provided all resident inspection, QC testing and contract administration during construction.

The rehabilitation included the construction of a new spillway, placement of a sand drainage blanket over most of the downstream face of the dam embankment, and the placement of a toe drain system. An emergency spillway was designed and constructed to pass a 75% "Probable Maximum Precipitation" storm event.

New Dam Design and Construction

City of Greeley, Weld County, Colorado

Engineering Analytics designed a Roller Compacted Concrete (RCC) dam for Peterson Reservoir to replace an existing earthfill dam constructed in the 1930s. Peterson Reservoir is located in Larimer County at an elevation of 9,500 feet. The original dam was removed and a 75 foot high RCC dam was constructed in approximately the same location as the earthfill dam. EA provided all geotechnical investigations, materials testing, RCC mix designs, and the structural design for the dam. EA also provided construction QC services and resident inspection during construction.

Existing Dam Rehabilitation

Colorado Division of Parks & Wildlife, Jefferson, Colorado

Engineering Analytics was the Engineer of Record for the design and construction services for rehabilitation and reconstruction of Davis Dams #2 and 3 at Staunton State Park.  EA conducted all subsurface investigations; provided the geotechnical and structural design; the hydrologic and hydraulic design of the spillway and outlet works; and the construction inspection and quality assurance testing.  The rehabilitation included the installation of an upstream seepage cutoff and clay face blanket; downstream seepage control with toe drains; new outlet works including new intake structure, control gate, conduit, and energy dissipater; and, new spillways.

Existing Dam Rehabilitation

Tongue River Dam, Decker Montana

Tongue River Dam was originally constructed in the 1940s and impounds a 49,000 acre-foot reservoir.  The 93-foot high dam is a zoned earth fill embankment.  The reservoir provides water for irrigation, industrial uses and a fish hatchery.  Tongue River State Park is located on the west shore of the reservoir.  This high hazard dam was in need of rehabilitation by the early 1990s.  Engineering Analytics staff proved the design for the rehabilitation of the dam, spillway and outlet works.  The design included replacing the principal spillway and raising the crest elevation of the spillway 4 feet to provide an additional 14,000 acre feet of storage.  The embankment required a new toe drain system to address seepage.  The low level outlet was upgraded with new gates.  The access and maintenance roads were also upgraded.