Bassano Dam Emergency Spillway Project

Following the June 2013 flood in southern Alberta, an emergency spillway was identified as a requirement to adequately protect the existing works of the Bassano Dam and ensure the delivery of water to the Eastern Irrigation District. NGLP was awarded this contract that consisted of the construction of an emergency spillway adjacent to the existing Bassano Dam in Bassano, AB and site preparation work. Stages of work for this project included: site preparation; the excavation of the spillway area; the construction of the spillway; the setting of bridge girders, radial gates, and hoist deck panels; and the completion of the control room and electrical scopes of work.

The Bassano Dam Emergency Spillway Structure includes: 12,500m³ of cast-in-place structural concrete, 235,400m³ of excavation, 210,400m³ of backfill and embankments, the supply and installation of a 120m of precast bridge deck, the installation of 10 structural steel radial gates (10.5m x 8m) complete with hoists, 10 structural steel stop logs completed with hoist truss, and twin 5-ton hoists. The concrete scopes of work are being completed with one of NGLP’s owned batch plants. The general scope of work included in the Bassano Dam Emergency Spillway Project included:

The site preparation phase of this project was executed with over 60% of the workforce demonstrating the successful partnership between Siksika Nation and Graham (NGLP). The project involved close cooperation between both partners and significant input from the majority partner Siksika Nation. Additionally, given the location of the project near the Bow River, this project involved significant environmental management considerations and planning. From a technical standpoint, the Bassano Dam project had very few issues. Any issues were small constructability issues which NGLP and the client were able to work through together to ultimately deliver the project on time and on budget.

A major lesson learned on the Bassano Dam project was regarding labour relations. NGLP was responsible for integrating workers from the Siksika Nation into a union-based building-trades workforce. Non-union employees within The Siksika Nation needed letters to work on the project which took time more time than was initially anticipated. Ultimately, NGLP was successful in creating a unified workforce by ensuring that all parties were aligned in their focus and ensuring Siksika members employed were given sufficient opportunities to get on the job training and grow their skill sets. NGLP was able to engage the design team in discussions about small design changes throughout the project. Minor constructability changes were made in agreement with the owner such as eliminating slab construction joints, the cut and fill mapping/sequencing and allowing for prefabrication of the electrical control building to be completed offsite. The common theme throughout this project – which allowed the on-time, on-budget completion of the work– was excellence in collaboration. NGLP successfully engaged the client and design team in discussions throughout the project regarding small design changes, such as those discussed in deviations; eliminating slab construction joints, the cut and fill mapping/sequencing and allowing for prefabrication of the electrical control building to be completed offsite. Furthermore, NGLP’s success in collaboration also extended to the lasting relationships built with members of the Siksika Nation. Another major success of the project was the work sequencing, which aligned to allow synergy between scopes. Through this well thought out sequencing, NGLP was able to have earthworks equipment operators operate mixer trucks during concrete pours, thus ensuring manpower was used efficiently and eliminated any duplications of manpower.