Penticton - Ellis #4 Dam Upgrade

completed

The City of Penticton is located in the Okanagan Valley in the Southern Interior of British Columbia with a population of 34,000. Ellis #4 Dam is situated at the head of the north fork of Ellis Creek, approximately 16 km from Penticton. The existing embankment dam is approximately 10 m in height and about 550 m in length. Discharge infrastructure at the dam includes a low-level outlet and a concrete spillway near the right abutment. Assessments of the dam have identified deficiencies in the structure’s ability to safely pass design flows as well as structural stability issues. The purpose of the Ellis #4 project is to rehabilitate the existing dam to mitigate the potential for dam failure resulting from more extreme weather events resulting from climate change and other natural disasters in turn mitigating downstream flood risks as well as satisfying CDA Guidelines and BC Dam Safety Regulations. The consequences of dam failure are considered extreme and the rehabilitation will protect human life as well as industrial and commercial properties downstream within the City. The rehabilitation of the dam will involve: • Installation of a gabion armoured spillway to supplement the existing concrete spillway and increase overall discharge capacity, • Stabilization of the structure through the removal and replacement of liquefaction susceptible fill over ±180m of the dam, • Replacement of the low-level outlet structure. • Replacement of the debris boom