Little Bow Reservoir

The Little Bow Reservoir, located in southern Alberta, is one of three major reservoirs that make up the Carseland-Bow River Headworks (CBRH) system which supplies water to the Bow River Irrigation District. The CBRH system supplies water for irrigation and municipal and landowner water users, and provides opportunities for a variety of recreation activities.

Challenges

  • Increased storage capacity and improved flood handling capabilities required to meet dam safety guidelines
  • Old outlet structure needed to be replaced while continuing water supply for downstream users
  • Several challenging instream activities needed to be carried out, including replacement of riprap, construction of cofferdams, and tie in of inlet and outlet channels

Solutions

  • Dam raised by 3.5 m and extended from 1200 m to 3300 m in length
  • Outlet structure replaced with new structure and seamlessly transitioned while maintaining continuous water supply
  • Reservoir lowering was coordinated with construction activities to facilitate instream work
  • Earthfill cofferdams built upstream of new outlet structure to continue water supply during construction
  • Riprap protection upgraded on upstream dam slope

Successes

  • Minimized disturbance footprint with borrow areas situated in reservoir areas
  • Maintained uninterrupted passage of flow to BRID canal system
  • Increased water storage in the reservoir
  • Reduced maintenance requirements and improved dam safety, system performance and capacity
  • Constructed a New Provincial Recreation Area with camping facilities, 350 trees and shrubs planted, solar powered drip irrigation system, and a sheltered boat launch