Northern pike (Esox lucius), a non-native predatory fish species, had negatively impacted trout populations in Lake Davis.
Cardno prepared an EIR/EIS for the California Department of Fish and Game to evaluate eradication of the invasive species from the reservoir and control of discharges to Big Grizzly Creek, including modifications to instream flows for the drawdown.
The EIR/EIS evaluated the environmental effects of a proposed project and five other project/action alternatives involving the drawdown of Lake Davis and the application of liquid or powder rotenone formulations, a piscicide. One alternative was for the complete dewatering of the reservoir without chemical treatment.
Cardno examined the potential economic, biological, and physical impacts resulting from the implementation of any given alternative and developed feasible mitigation recommendations. The EIR/EIS was finalised with no legal challenges.