PROJECT EXECUTIVE SUMMARY INARY FINAL ENVIRONMENTAL IMPACT STATEMENT of magnitude, duration, extent, and likelihood, road construction, maintenance, and use esult in short- and long-term impacts to streams and drainages from increased surface and deposition of fine sediments; alteration of water temperature; delays or barriers to igration at culverts; changes in streamflow and hydrologic processes; and introduction of invasive plant species. The duration of construction-related sedimentation would be temporary and short-term, due mitigation and control measures, State of Alaska permit stipulations, and timing windows. Additional monitoring, BMPs, and maintenance standards may be required by ROW lease stipulations from state and local governments. Operations are expected to require 359 truck round trips per day, which would result in dust impacts in proximity to roads, including at stream crossings. Implementation of dust suppression and enforcement of slow speed limits at all stream crossings would minimize dust-related impacts to aquatic ecosystems. Potential impacts to fish values at the Amakdedori port site under the Applicant?s Preferred Alternative include direct loss of marine habitat; fish displacement, injury, and mortality; changes to marine productivity; increased sedimentation and turbidity; and impacts to fish migration. In terms of magnitude and extent, placement of the caisson dock at the port site would permanently impact 2.1 acres of marine benthic habitat. These impacts would be certain to occur if the project is permitted and the Amakdedori port is built. Alternative 1 and Variants The magnitude, duration, extent, and likelihood of direct and indirect impacts to fish, aquatic habitat, streamflow, productivity, sedimentation and turbidity, and fish migration due to construction and operations at the mine site under Alternative 1 would be same as those described for the Applicant?s Preferred Alternative. Potential impacts to fish values along the transportation and natural gas pipeline corridors under Alternative 1 are similar to those described for the Applicant?s Preferred Alternative. Other impacts include fish displacement, injury, and mortality at these locations; changes in stream surface water flows; increased sedimentation and turbidity at crossings and terminal sites; and potential impacts to fish migration. In terms of magnitude and extent, the road and onshore pipeline corridors would cross 52 anadromous and resident fish streams (41 fish stream crossings for the Kokhanok East Ferry Terminal Variant), compared to 55 fish stream crossings for the Applicant?s Preferred Alternative. These crossings would directly impact 6.5 acres of riverine wetland habitat (6.4 acres of riverine wetlands for the Kokhanok East Ferry Terminal Variant), compared to 3.5 acres of riverine wetland habitat for the Applicant?s Preferred Alternative. The impacts on fish values due to the loss of this aquatic habitat would be greater in magnitude due to loss of riverine wetlands as those described for the Applicant?s Preferred Alternative. Docking facilities for the ice-breaking ferry at the north and south ferry terminals under Alternative 1 would include rock and gravel ramps extending approximately 105 feet and 155 feet, respectively, into lliamna Lake. The magnitude and extent of impacts to aquatic lake habitat are such that the ramps would cover approximately 0.1 acre of shallow lake aquatic habitat and 185 feet of shoreline habitat at the north terminal, and 0.7 acre and 738 feet, respectively, at the south terminal, compared to 1.66 acres for the Applicant?s Preferred Alternative. The magnitude and extent of loss of aquatic habitat from construction, operations, and closure of the Cook Inlet natural gas pipeline under Alternative 1 would not differ from those described for the Applicant?s Preferred Alternative. The lliamna Lake pipeline route crossing the lake under Alternative 1 is shorter than that for the Applicant?s Preferred Alternative. Therefore, direct impacts of displacement, injury, or FEBRUARY 2020 PAGE 71