rock drainage, effects of roads and bridges on fish (roads supporting the Pebble mine could cross 20 known salmon streams), and general water pollution-related concerns. The U.S. Environmental Protection Agency (EPA) began conducting a scientific review of the Bristol Bay watershed in 2011 focused on the Nushagak and Kvichak river drainages, in response to petitions from tribes, commercial fishing organizations, and other organizations opposed to Pebble. The agency completed the review in 2014. See Legal challenges. The U.S. Army Corps of Engineers (USACE) released its final Environmental impact statement (EIS) for the Pebble Mine project in July 2020, concluding that the project would not lead to "long-term changes in the health of the commercial fisheries in Bristol Bay," under normal conditions. After a preliminary draft of this final statement was sent to federal and state agencies, many other scientific and administrative groups critiqued this conclusion. The U.S. Fish and Wildlife Service stated that the EIS did not consider habitat destruction that could lead to destruction of salmon stocks in Bristol Bay. The legal director of Trustees for Alaska, a nonprofit public interest law firm, indicated that the report was "lacking and thoroughly inadequate." Possible mining plan The mine itself would be an open-pit mine a mile square in area and a third of a mile deep. Ponds would be dammed to contain tailing, including some toxic materials. A 165-mile natural gas pipeline would be constructed to provide power for the operation, as well as 80 miles of road and pipeline to transport the mined concentrate to Cook Inlet. Operating the mine would use and impound large amounts of surface water. The roads would carry fuel, industrial chemicals and supplies. Pebble East would most likely be an underground mine. Pebble would be similar to existing large copper porphyry mines such as Chuquicamata, Bingham Canyon and Ok Tedi, although the environmental setting and various technical considerations of Pebble distinguish it from these desert and tropical examples. Development and construction would consume years and cost billions of dollars. Required infrastructure includes miles of roads, bridges and power lines with pipelines for fuel and rock slurries. Design possibilities include: construction of a port on Iniskin Bay of Cook Inlet with a two-lane freight road roughly long built along the north side of Lake Iliamna between the mine and the new port; trucks hauling ore concentrate to the port; pipelines along the road to carry