Large stretches of salmon-spawning streams and thousands of acres of wetlands would be wiped out if a large-scale mining project were to be built in southwestern Alaska\'s copper-rich Bristol Bay region, according to a report issued Friday by the Environmental Protection Agency. The report, while not directly addressing it, is a potential blow to the massive Pebble copper and gold mine operation proposed by an international alliance of mining interests, and opposed by environmentalists and local native groups. Risks from building and operating such a big mine, or series of mines, range from the near-certain loss of wetlands and streams and chronic water pollution to a remote possibility of a catastrophic breach in a tailings dam planned to be taller than the Washington Monument, the report said. The report uses elements of the Pebble plan and other information about modern mining practices to project a future scenario, an EPA manager said Friday, but the agency made it clear it is not pre-judging the Pebble mine issue. \"EPA\'s draft study does not provide an in-depth assessment of any specific mining project, but instead assesses the potential environmental impacts associated with mining activities,\" the EPA wrote in a statement on its website. \"The draft study in no way prejudges future consideration of proposed mining activities.\" The Bristol Bay watershed assessment, now subject to public comment and scientific peer review, was initiated more than a year ago at the request of Alaska Native groups in the region. Those and several fishing and environmental groups have asked the EPA to invoke its authorities under the Clean Water Act to preemptively block development of the Pebble mine. \"What is most directly identified is what you would expect -- where there is a mine footprint, you would be losing streams and wetlands and habitat areas,\" Dennis McLerran, the EPA\'s Pacific Region director, said on a telephone conference call with media after releasing the report. McLerran said the EPA is far from making any decision to stop development of the mine. \"This document itself will inform future decisions, but we\'re not ready or at the point to make any of the future decisions yet,\" he said. The Bristol Bay region is famous for its huge runs of salmon. All five species of Alaska salmon are native to the area, which produces nearly half of the world\'s sockeye salmon, the EPA study said. Salmon fisheries and related natural resources support 14,000 jobs and have an average annual value of $480 million, the report said. The Bristol Bay region is also famous for its abundant wildlife, including migratory birds and salmon-eating brown bears, as well as parks and wildlife refuges. But the wild region\'s mineral resources have inspired Britain\'s Anglo American Plc and Canada\'s Northern Dynasty Minerals Ltd to form a partnership to pursue what would be one of the world\'s largest open-pit copper mines at Pebble. Earlier this week, Northern Dynasty announced that the companies\' jointly owned Pebble Limited Partnership would be spending $107 million this year to start securing development permits. Mine supporters and the administration of Alaska Governor Sean Parnell have objected to the EPA study. They argue that it is a prelude to development-stopping action by the EPA. The president of the Pebble Limited Partnership on Friday called EPA\'s draft \"rushed\" and said it lacked \"the level of rigor and completeness required for a scientific assessment.\" \"We believe it would be unprecedented and entirely inappropriate for the EPA to take steps to stop our project before it has been fully designed, before we have presented an environmental mitigation strategy designed to protect the fish and water resources of the area, before we have completed an economic benefits study and before we have submitted a permit application and started the rigorous permitting process,\" Pebble Partnership President John Shively said in a statement. Pebble Mine opponents applauded EPA\'s efforts. \"What we have read so far suggests that EPA\'s draft findings regarding mining the Pebble deposit largely align with our own,\" said Jason Metrokin, chief executive of Bristol Bay Native Corp, in a statement. \"The science exists now to show that the proposed Pebble mine does not fit with a sustainable future for Bristol Bay, and should not be allowed to proceed.\"