Shell Lake Flow Control Feasibility Assessment

Cook Inlet Aquaculture Association (CIAA), in partnership with HDR Engineering, Inc., completed a feasibility assessment to evaluate whether a flow control structure at the outlet of Shell Lake could be used to control water levels for the suppression of invasive northern pike. The final report was completed in December 2025 and assesses design options, permitting considerations, cost, and potential ecological effects. Project activities included background data review, hydrologic data collection, installation of a water level pressure transducer, aerial imagery collection, and public outreach. HDR evaluated multiple flow control designs and identified two feasible options: a buried pipeline at the outlet of Shell Lake and a flow control structure within Shell Creek. Results of the study provide CIAA and other agencies with another potential management tool for invasive northern pike control.

Conducting a flow control feasibility assessment at Shell Lake has the potential to change the way resource managers approach pike suppression efforts within the Susitna River watershed. Although a flow control structure would be a large initial investment, over time it would be a more cost-effective approach to suppress or to possibly even eradicate northern pike in suitable lake systems while also benefiting the movement of native fish species. In the long run, this project could benefit sockeye, coho, Chinook, and pink salmon as well as resident fish species in Shell Lake through adding a tool to our toolbox for reduction in northern pike predation. Increased salmon runs into Shell Lake would also benefit terrestrial, avian, and marine mammal species that feed on salmon and will increase the transfer of marine-derived nutrients through decaying salmon carcasses to further boost the productivity of the ecosystem.