v>EPA

FACT SHEET

CWA Section 404(c) Final Determination
for the Pebble Deposit Area of the Bristol Bay Watershed

January 2023

The U.S. Environmental Protection Agency is limiting the use of certain waters in the Bristol Bay watershed as
disposal sites for certain discharges of dredged or fill material associated with development of a mine at the
Pebble deposit, a large ore body in southwest Alaska.

After extensive review of scientific and technical research spanning two decades, and robust stakeholder
engagement, EPA has determined that certain discharges associated with developing the Pebble deposit will
have unacceptable adverse effects on certain salmon fishery areas in the Bristol Bay watershed. This Final
Determination is exercising EPA's authority under Section 404(c) of the Clean Water Act1 (CWA). In the 50-year
history of the CWA, EPA has used its Section 404(c) authority judiciously. This action marks the third time in 30
years, and only the fourteenth time in the history of the CWA, that EPA has used this authority. This action does
not apply to any other resource development projects in the State of Alaska.

The Bristol Bay Watershed—A Critical Resource

Alaska's Bristol Bay watershed, home to 25 Alaska Native villages and communities, is an area of unparalleled
ecological value, with salmon diversity and productivity unrivaled anywhere in North America. The region provides
high-quality, diverse, and connected aquatic habitats, from headwaters to ocean, that support abundant,
genetically diverse wild Pacific salmon populations. These salmon populations have supported Alaska Native
cultures for thousands of years and continue to support one of the last intact salmon-based cultures in the world.
The Bristol Bay watershed produces approximately half of the world's Sockeye Salmon, and salmon fisheries are a
huge economic driver in the region, supporting approximately 15,000 jobs annually and generating an estimated
$2.2 billion in 2019 alone. These salmon populations also help to maintain the productivity of the entire
ecosystem, including numerous other fish and wildlife species. Together, the Bristol Bay watershed's diverse and
largely undisturbed aquatic habitats and productive salmon populations form the foundation of this globally
significant ecological and cultural resource.

Pebble Mine

The Pebble deposit, a large, low-grade deposit containing copper-, gold-, and molybdenum-bearing minerals, is
located at the headwaters of the pristine Bristol Bay watershed. The Pebble deposit underlies portions of the
South Fork Koktuli River (SFK), North Fork Koktuli River (NFK,), and Upper Talarik Creek (UTC ) watersheds, which
drain to two of the largest rivers in the Bristol Bay watershed, the Nushagak and Kvichak Rivers.

Development of a mine at the Pebble deposit has been the subject of study for nearly two decades. EPA's Final
Determination is based on this extensive record of scientific and technical information and applies only to
certain discharges of dredged or fill material associated with developing the Pebble deposit.

1 Section 404(c) of the CWA authorizes the EPA: to (1) prohibit or withdraw the specification of any defined area as a
disposal site, and (2) deny, restrict, or withdraw the use of any defined area for specification as a disposal site, whenever it
determines, after notice and opportunity for public hearings, that the discharge of dredged or fill material into the area will
have an unacceptable adverse effect on municipal water supplies, shellfish beds and fishery areas (including spawning and
breeding areas), wildlife, or recreational areas.

-------
EPA's Final Determination

EPA has determined that the large-scale loss of, and damage to, headwater streams, wetlands, and
other aquatic resources that support salmon populations in the SFK, NFK, and UTC watersheds from
the discharge of dredged or fill material for the construction and routine operation of the 2020 Mine
Plan described in Pebble Limited Partnership's June 8, 2020 CWA Section 404 permit application, as
well as future proposals that would have the same, similar, or greater levels of aquatic resource loss or
damage will have unacceptable adverse effects on anadromous2 fishery areas in the these watersheds.

Discharges of dredged or fill material to construct and operate the proposed mine site alone would
result in the permanent loss of approximately 8.5 miles (13.7 km) of anadromous fish streams, 91 miles
(147 km) of additional streams that support anadromous fish streams, and approximately 2,108 acres
(8.5 km2) of wetlands and other waters in the SFK and NFK watersheds that support anadromous fish
streams. These discharges would also result in streamflow alterations that would adversely affect
approximately 29 miles (46.7 km) of additional anadromous fish streams downstream of the mine site
due to greater than 20 percent changes in average monthly streamflow. The aquatic resources that
would be lost or damaged play an important role in supporting salmon populations in the SFK, NFK,
and UTC watersheds.

EPA's Final Determination specifically:

•	Prohibits the specification of certain waters of the United States in the SFK and NFK watersheds as disposal
sites for the discharge of dredged or fill material for the construction and routine operation of the 2020
Mine Plan. This includes future proposals to construct and operate a mine to develop the Pebble deposit
with discharges of dredged or fill material into waters of the United States anywhere at the mine site that
would result in the same or greater levels of aquatic resource loss or streamflow changes as the 2020 Mine
Plan; and

•	Restricts the use for specification of certain waters of the United States in the SFK, NFK, and UTC watersheds
as disposal sites for the discharge of dredged or fill material associated with future proposals to construct
and operate a mine to develop the Pebble deposit with discharges of dredged or fill material into waters of
the United States that would result in adverse effects similar or greater in nature and magnitude to the
adverse effects of the 2020 Mine Plan.

Why This Action Matters

By prohibiting and restricting the discharge of dredged or fill materials associated with developing the Pebble
deposit in certain areas of the Bristol Bay watershed, EPA prevents unacceptable adverse effects on important wild
salmon habitat, and in doing so also helps safeguard the critical Bristol Bay ecosystem. The region's salmon
resources have supported Alaska Native cultures for thousands of years and continue to support one of the last
intact salmon-based cultures in the world. Together, the Bristol Bay watershed's largely undisturbed aquatic
habitats and productive salmon populations create this globally significant ecological and cultural resource. The
streams, wetlands, and other aquatic resources of the Bristol Bay watershed also provide the foundation for
world-class, economically important, commercial and sport fisheries for salmon and other fishes.

2 Anadromous fishes hatch in freshwater habitats, migrate to sea for a period of relatively rapid growth, and then return to
freshwater habitats to spawn. For the purposes of this Final Determination, "anadromous fishes" refers only to Coho or
Silver salmon (Oncorhynchus kisutch), Chinook or King salmon (O. tshawytscha), Sockeye or Red salmon (O. nerka), Chum or
Dog salmon (O. keta), and Pink or Humpback salmon (O. gorbuscha).

-------