Holbrook Reservoir is an existing water storage reservoir owned by the Holbrook Mutual Irrigation Company. The reservoir is in a broad shallow basin formed in overburden soils overlying the Smokey Hill Member of the Niobrara Formation.
The reservoir is impounded by a 20-foot high earth dam embankment which stores approximately 6,200 acre-feet at the normal water level (NWL). The dam and appurtenant facilities are in poor condition and need to be rehabilitated.
Historically the reservoir has stored agricultural irrigation water for the Company members. The City of Aurora is in need of additional raw water storage in the Arkansas Valley and has partnered with the Irrigation Company to investigate reconstructing and raising the dam to increase the reservoir storage.
In the winter of 2006, Deere & Ault Consultants, Inc. was retained by the City to evaluate the feasibility of raising the dam. Following completion of the feasibility study and geotechnical investigation, Deere & Ault in conjunction with CDM was retained to complete additional investigations and prepare 30 percent design drawings for the project.
The designed enlargement will raise the existing dam embankment with an “upstream” raise of approximately 11 feet. The reservoir storage will be increased from 6,200 acre-feet to 16,000 acre-feet, a net increase of 9,800 acre-feet. The City of Aurora is considering the project in its future plans in the Arkansas Valley.
Client: City of Aurora