Providing Adult Fish Passage and Improving Juvenile Fish Passage at McIntyre Dam on the Okanagan River, BC

McIntyre Dam is located between the cities of Oliver and Okanagan Falls, British Columbia. Its two primary functions are to control water levels on the Okanagan River between Vaseux and Osyoyoos lakes and provide irrigation water for agriculture and municipality purposes.  When this dam was constructed in 1954, no upstream fish passage provisions were included. McIntyre Dam has been the upstream fish migration barrier for Okanagan sockeye (Oncorhynchus nerka), steelhead (O. mykiss) and Chinook (O. tshawytscha).

In 2009, the McIntyre Dam Project refitted the dam with fish friendly gates in order to provide adult salmon passage upstream and improve juvenile salmon migration downstream by: 1) Replacing the existing five undershot gates with five overshot gates; 2) Building a riffle and pool configuration downstream of the dam to provide adult salmonids additional water depth for jumping over the gates; 3) Monitoring the impacts on sockeye salmon migration (juvenile and adults); and 4) Installing a permanent fish screen on the city irrigation canal to prevent accidental entrainment.

The completion of this project provides an additional 8 km of spawning and rearing habitat in the Okanagan River and Vaseux Lake, historic habitat which has not been utilized by anadromous fish within the last  six decades. In the two years after retrofitting the overshot gates, spawner enumeration surveys have shown thousands of adult sockeye ascending McIntyre Dam, swimming past Vaseux Lake and arriving at the next passage barrier (Skaha Dam) at the outlet of Skaha Lake in Okanagan Falls. Redd surveys have shown that spawning sockeye and Chinook utilized the available habitat located between McIntyre Dam and Skaha Dam. Acoustic surveys provided information on migration timing in the area. Biosampling surveys have shown no morphological variation, in term of fish size or population structure, between adult sockeye spawning above and below McIntyre Dam.

As part of a re-introduction experimental study, Skaha Lake has received over 7 million hatchery sockeye fry over the past eight years. Preliminary juvenile downstream migration monitoring results indicate a decrease in the rate of injury, such as de-scaling, after retrofitting the overshot gates.

The positive results to date has led to agency and community support to continue identifying other passage barriers that could prove to be successful in providing  fish passage opportunities which could potentially open up nursery lakes for juvenile sockeye in the future.