Twinned Watersheds Project:

Fish Habitats

Salmon are a good measure of watershed health.

This project enabled robust research, lead by Geomorphic Consulting in collaboration with local scientists and field crews, to determine the necessary water levels and habitat conditions for salmon and other species to thrive, or at least survive, in the Koksilah and Chemainus Rivers.

Throughout the summer of 2021, as water levels dropped, field crews walked the two rivers to monitor how various habitats were impacted by declining flow rates. Pool, riffle, and glide habitats were inventoried to see if there was enough water for fish – specifically juvenile Coho and Steelhead fry, and returning adult Chinook.

See the Documents section on this page to download the peer reviewed study results or an Executive Summary.

Access the full Habitat Atlas that was generated by this project here, or see the map-sets on this page.

Photo Gallery

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Khowutzun Forestry Service crew on day one of training for aquatic research in the Koksilah River. CWB photo by Chloe Mitchell.

Posted on August 18, 2022

Video: Biologist Cheri Ayers describes the Koksilah-Chemainus "Twinned Watersheds" Project

Cheri Ayers is a local fish biologist who grew up on the Koksilah River, and is now serving as the Fish Habitat and Flows Assessment Project Manager for the Twinned Watersheds project. She describes this important partnership effort to better understand climate and other impacts on fish habitats in the Koksilah and Chemainus Rivers so

Posted on August 3, 2022

Video: Why Fish Need Water

Cowichan Watershed Board’s Tim Kulchyski and Tom Rutherford answer common questions about the why, when, where and how much fish need water in the Cowichan/Koksilah watershed.

Posted on April 15, 2022

Twinned Watershed Project: Executive Summary – Koksilah River Environmental Flow Assessment

Water holds a prominent place in culture, science, policy, community values and recreational pursuits. Yet, it remains undervalued in comparison to the role that it plays in society and in the cycle of life in the Cowichan Valley, British Columbia. To explore the importance of water in the Xwulqw’selu Sto’lo (Koksilah River), an Environmental Flow