Apple Gate

Ridges Basin Dam & Lake Nighthorse, Photo by Richard Stenzel
Ridges Basin Dam & Lake Nighthorse, Photo by Richard Stenzel

Dams and Reservoirs

We provide the necessary services for the evaluation of new water storage projects that require dams. These services range from determining their feasibility at a conceptual level to completing permitting, final design, bid documents, and construction administration. We also offer continuing services including annual inspections, review and update of emergency preparedness plans, and dam safety monitoring.

Specific Project Experience

Broomfield Reservoir

Applegate Group served as part of a team of consultants to design a new raw water storage reservoir for the City of Broomfield. An off channel site, owned by the city, was selected as the reservoir location due to a minimal amount of environmental constraints and the close proximity to the cities service area. The proposed Broomfield Reservoir will be a Large, High Hazard dam with a structural height of approximately 90 ft and a storage capacity of 5,000 acre ft. Applegate Group was retained to perform the hydrology analysis for the drainage basin, the hydraulic design of a spillway and multi-level outlet tower. Construction is expected to start in 2010 and Applegate Group staff will perform construction observation during construction of the spillway, outlet works and other appurtenant structures.

Fortune Reservoir (Welton Dam)—Design and Construction Management

Consolidated Mutual Water Company retained us in 1995 to assist in finding an economically feasible dam site.  In 1996, the Welton Dam site was identified as an ideal off-channel reservoir site having minimal environmental constraints and requiring no Federal permits.  Existing on-site clay shale materials were used to build a conservative embankment dam incorporating a grout curtain, chimney and blanket drains, and pressure relief wells.  The dam is 120’ high, a crest length of 5,200’, has storage capacity of 10,000 acre-feet, and an embankment volume of 5,000,000 cubic yards. The total construction value of the project is approximately $15,000,000.  Applegate Group is the Engineer of Record and completed this project on time and under budget.

Clear Creek County Reservoir Feasibility Study

Applegate Group has been providing ongoing engineering services for Clear Creek County with the development of their water bank.  Nine potential reservoir sites that Clear Creek County previously filed conditional water rights on (with the assistance of Applegate Group) were investigated for site access, existing land use, geologic hazards, environmental risks, and constructability issues. After the investigation phase, the nine sites were ranked using a Multi-Criterion Decision Analysis tool. To help fund this project, Applegate Group prepared the application material for grant funding through the House Bill 1177 Basin Roundtable and CWCB process. This grant was approved for $52,000 for this phase of the feasibility work and the next phase will be to create a plan for development of these reservoir sites.

Empire Reservoir Rehabilitation

Applegate Group was retained by the Bijou Irrigation District to design a rehabilitation program for the East Embankment Dam of Empire Reservoir. The dam had experienced severe erosion along the east Embankment including failure of an existing parapet wall, and heavy erosion near existing cottonwood trees located on the upstream face of the dam. Applegate Group prepared an alternatives analysis for the repair including a study of soil cement, articulating concrete blocks and conventional riprap. A submittal package was prepared for the review by the Colorado State Engineer’s Office (SEO) and approval was granted within 2 weeks.  Applegate Group also assisted Bijou Irrigation District obtaining a low interest loan from the CWCB to pay for the project.

Martin Lake Reservoir

Applegate Group was retained by the owner of Martin Lake Reservoir to formulate a rehabilitation plan that would address the State Engineer Office concerns regarding the nearly inoperable outlet works. This high hazard dam is located west of Walsenburg, CO. The reservoir outlet works had become increasingly difficult to operate in recent years and had significant valve leakage. Applegate Group, Inc. worked with a video inspection company and performed an internal inspection of the outlet. The inspection revealed the outlet pipe to be in very poor condition and the outlet valve leaking at multiple locations. Our design recommendations included a complete outlet replacement with new intake structure, discharge structure, service spillway, guard gate, service gate and dual outlet pipes. The project was approved by the State Engineer’s Office with construction scheduled to begin in January, 2009.