TRIP REPORT State of Alaska Department of Fish and Game Field Date(s): October 14, 2019 Location(s): Ikalukrok Creek Near Red Dog Mine Objective(s): Document Sources of Turbid Water into Ikalukrok Creek Participant(s): Chad Bear Weather: 20°F to 30°F, 35 mph wind, clear skies Access: Jet Ranger II Helicopter provided by Red Dog Mine On October 14, 2019, Chad Bear flew to the Red Dog Mine and performed a survey of the Ikalukrok Creek drainage to document the sources of turbidity in the drainage (Figure 1). Ikalukrok Creek became noticeably turbid in late August or early September of 2019. Twelve tributaries and seeps were found to be visually contributing turbidity, with nine of the tributaries upriver from Red Dog Creek. The annual aerial surveys for chum salmon and Dolly Varden in the Wulik River and Ikalukrok Creek could not be conducted in 2019 due to the reduced visibility from turbid waters in Ikalukrok Creek (see ADF&G Trip Report 10-14-19).

Figure 1. Sources of Turbidity (Red) into Ikalukrok Creek near Red Dog Mine, Oct. 14, 2019.

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The survey began at the confluence of the Wulik River and Ikalukrok Creek and followed the turbid water upriver to its sources. Just downriver from this confluence is typically where large concentrations of Dolly Varden overwinter. In late fall, before freeze-up, the entire Wulik River is usually clear with no turbidity. During this survey, turbid water from Ikalukrok Creek mixed with the clear water of the Wulik River at their confluence (Figure 2). The Wulik River upriver from Ikalukrok Creek had very low levels of turbidity.

Figure 2. Confluence of Ikalukrok Creek (turbid) and the Wulik River (clear), October 14, 2019.

Following Ikalukrok Creek upriver from its confluence with the Wulik River all tributaries entering the drainage from the east and west sides were clear until Mainstem Red Dog Creek. This includes Dudd Creek (Figure 3) which is fed by Anxiety Ridge, Buddy and Bons Creek drainages.

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Figure 3. Confluence of Dudd Creek (clear) with Ikalukrok Creek (turbid), October 14, 2019.

Bonn’s Pond had turbidity entering from a creek on the north side of the reservoir, but it did not discolor the flowing waters of Buddy and Dudd Creek (Figure 4). This creek is not near any disturbed land or mining activity.

Figure 4. Unnamed Creek on north side of Bonn’s Pond on October 2, 2019.

Low levels of turbidity were present at the confluence of Mainstem Red Dog Creek and Ikalukrok Creek (Figure 5). Following Mainstem Red Dog Creek upriver, two sources were turbid. The first one was Middle Fork Red Dog Creek that includes water from Red Dog Mine’s

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Tailing Water Discharge system (Figure 6) and the Kaviksaaq Seep. The second was from a tributary to North Fork Red Dog Creek originating from the hill side (Figure 7).

Figure 5. Confluence of Mainstem Red Dog Creek (bottom) and Ikalukrok Creek (left).

Figure 6. Confluence of Middle Fork Red Dog Creek (bottom) and North Fork Red Dog Creek (right).

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Figure 8. Figure 7. Tributary of North Fork Red Dog Creek (right) Contributing turbidity to North Fork Red Dog Creek (left).

Continuing upriver from the confluence of Mainstem,Red Dog Creek with Ikalukrok Creek, nine tributaries and seeps draining from both the east and west side contributed substantial amounts of turbidity. Moil Creek (Figure 8) and Noa Creek (Figure 9) originate from hills from the west side of the drainage and both were turbid. Grayling Junior Creek entering from the east side of Ikalukrok Creek also was turbid (Figure 10). Grayling Junior Creek had two tributaries near its headwaters that added discolored water into the drainage.

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Figure 8. Moil Creek (top) entering Ikalukrok Creek (bottom) from the West Side of Ikalukrok Creek.

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Figure 9. Noa Creek (top) Entering from the West Side of the Ikalukrok Creek Drainage (bottom).

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Figure 10. Grayling Junior Creek (top) confluence with Ikalukrok Creek (bottom).

Continuing up Ikalukrok Creek, clear water was flowing from the East Fork Ikalukrok Creek (Figure 11). Turbid water was still present in Ikalukrok Creek above its confluence with East Fork Ikalukrok Creek.

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Figure 11. Confluence of East Fork Ikalukrok Creek (bottom) and Ikalukrok Creek (top) and continuing down Ikalukrok Creek (left).

Continuing upriver past the confluence of the East Fork Ikalukrok Creek and Ikalukrok Creek several tributaries contributed turbid water, Cub Creek (Figure 12) from the east and the West Fork Ikalukrok (Figure 13) from the west side. Cub Creek has been documented as adding discolored water for many years, but the West Fork Ikalukrok Creek is typically clear.

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Figure 12. Cub Creek (bottom) entering Ikalukrok Creek (top), Oct 14, 2019.

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Figure 13. West Fork of Ikalukrok Creek (top) entering Ikalukrok Creek (bottom), Oct 14, 2019.

Past the confluence of the West Fork Ikalukrok Creek and Ikalukrok Creek, several very small tributaries from the west side of the drainage added turbid water. The furthest upriver source of turbidity found during this survey entered Ikalukrok Creek from the west at 68 11.498 N, -162 55.529 W (Figure 14).

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Figure 14. Furthest upriver source of turbidity entering Ikalukrok Creek from the west side on October 14, 2019.

Ikalukrok Creek was clear in all drainages entering from both the east and west sides upriver from the coordinates: 68 11.730 N, -162 55.331 W (Figure 15).

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Figure 15. Clear water in headwaters of Ikalukrok Creek. October 14, 2019.

The summer of 2019 had several high-water flow events recorded at the USGS Wulik River water gauge below the confluence with Ikalukrok Creek. The most recent high-water event before this trip was 5,000 CFS on October 1, 2019 (Figure 16). From June 1 to October 15, 2019 there were five high-water flow events (Figure 17). During the same summer months in 2018 there were three highwater events (Figure 18).

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Figure 16. USGS Wulik River Water Discharge (in CFS), Sept 28 – Oct 16, 2019.

Figure 17. USGS Wulik River Water Discharge (in CFS), June 8 – October 12, 2019.

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Figure 18. USGS Wulik River Water Discharge (in CFS), June 9 – October 13, 2018.

It is unknown why so many creeks were contributing turbid water to the Ikalukrok River this fall. It may be due to higher temperatures and melting permafrost, increased groundwater due to high precipitation (rain and snowfall), some combination of both, or some other factor.

Similar turbidity patterns have been observed in other drainages (Saviukviak, Kavik, Canning, and Hulahula rivers) in northern Alaska (Brendan Scanlon, ADF&G personal communication).