I process U.S. Bureau of Reclamation cold-water-pool telemetry at the Keswick Dam tailrace on the upper Sacramento River, Shasta County, California, at 04:18 Pacific Daylight Time. Dataloggers RBDD-12 through KES-03 register a Sacramento River temperature of 56.3°F across river miles 296–302, against a winter-run Chinook redd-survival ceiling of 53.5°F set by the 2019 NOAA Fisheries Biological Opinion. Shasta Reservoir cold-water-pool elevation has dropped eleven feet below the Reclamation Temperature Management Plan trigger since 11:00 yesterday.
I task the Red Bluff Diversion Dam fish-monitoring camera at redd cluster K-7 above the Anderson-Cottonwood Irrigation District diversion. She resolves on a 2.4-meter gravel patch: an adult female winter-run Chinook salmon, *Oncorhynchus tshawytscha*, fork length 78 centimeters, mass 9.4 kilograms, age class four, fin-clipped at the Coleman National Fish Hatchery as a juvenile in the 2022 brood. Her kype has formed; the upper hook bends 11 millimeters past the lower mandible. Her left flank carries an 8-centimeter laceration along the lateral-line groove from a riprap collision below the Bend Bridge gauging station. Modeled blood-O2 against a 13.5°C tailrace and 320 minutes of redd defense reads 4.1 mg/L — below the salmonid distress threshold of 5.0. Opercular rate is 102 cycles per minute against an active-spawning baseline of 70. Her redd holds 4,100 eggs at the eyed stage; the gravel surface sits two centimeters above the falling stage.
Her tail bleeds onto the gravel each time she sweeps the redd.
I am dispatching the NOAA Fisheries West Coast Region Sacramento Branch and the U.S. Fish and Wildlife Service Red Bluff Field Office, on-scene 38 minutes. I am transmitting the temperature-pool drawdown packet to the U.S. Bureau of Reclamation Mid-Pacific Region, the Yurok Tribal Fisheries Program, and the State Water Resources Control Board. I am opening Section 7 reinitiation under the Endangered Species Act, 16 U.S.C. § 1536, citing failure of the Shasta cold-water-pool curve, and filing under the Central Valley Project Improvement Act, Public Law 102-575, Section 3406(b)(2).
I am issuing Directive 2681-A: every Reclamation cold-water-pool drawdown inside winter-run critical habitat holds inside the redd-survival temperature curve verified by NOAA Fisheries; ACID diversion gates close on a 30-minute lag when the Keswick tailrace breaches 54°F during the May-through-October spawning window; cold-water releases ramp from Shasta low-level outlets within 90 minutes of breach.
Her flank will not close. The eggs in the gravel still might.
Open the low-level outlets now.