Science on the Little Su: Protecting Groundwater Connections for Mat-Su Basin Salmon Habitat Resilience

by | Nov 17, 2025 | Clean Water, Climate Change, Salmon

The Little Susitna supports Chinook and Coho runs that are central to local economies, subsistence traditions, and the health of our watershed. By mapping these critical cold spots, we can help ensure that healthy habitat is protected and guide conservation efforts in the face of climate change and increasing development pressure.

Thanks to your support, Inletkeeper will be launching a new science project on the Little Susitna River in summer 2026. The Little Susitna has been identified by regional partners as a top priority watershed for managing salmon habitats and as one of the most productive salmon fisheries in the Mat-Su region. The Little Susitna supports Chinook and Coho runs that are central to local economies, subsistence traditions, and the health of our watershed. But it is also one of the warmest rivers in the basin, and rising summer stream temperatures are creating real challenges for migrating salmon.

This coming summer, Inletkeeper will conduct aerial thermal imaging along 25 miles of the lower Little Susitna to identify hidden groundwater inflows— cool-water refuges that salmon use to rest and recover during their upstream migration. By mapping these critical cold spots, we can help ensure that healthy habitat is protected; guiding conservation efforts in the face of climate change and increasing development pressure.

The project builds on earlier thermal imagery collected in the Big Lake and Deshka River watersheds, expanding our understanding of where groundwater and surface water interact to sustain fish. The resulting high-resolution maps will be made publicly available and shared with partners including Alaska Department of Fish & Game, the Mat-Su Borough, and local land trusts. These tools will inform land-use planning, outreach to landowners, and conservation strategies designed to keep cold, clean water flowing where salmon need it most.

This is the type of work your generosity makes possible. By investing in science today, you are helping build the knowledge and partnerships needed to safeguard salmon habitat for generations to come. As Inletkeeper continues to champion science-based solutions, we are grateful for your role in helping us attain the match to make this research—and the future it protects—possible.

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