Prior to dam removal, the upper reaches below Iron Gate had the lowest water temperatures in 2022 and 2023 (Figure 7 and 8), reflecting the release of cold water from the bottom of Iron Gate Reservoir. Without this source of cold water, the upper reaches are now significantly warmer in late spring and summer. <\/p>\n\n\n\n
Because the water temperatures were similar in 2024 above and below the former Iron Gate Reservoir (see Figures 4 and 6), there seems to be little warming in the unforested former Iron Gate reservoir reach. The upper reach of river below Iron Gate Dam now generally reflects historic warm water characteristics of the 6-dam project reach between Klamath Lake and Iron Gate Dam. Future riparian forest restoration of the three former reservoir reaches may lead to some cooling of the upper river in the future.<\/p>\n\n\n\n
Finally, the drop in river flow in early July 2024 (see Figure 1) appears to have caused additional reservoir-footprint erosion and scouring, leading to high turbidity levels below Iron Gate (Figure 9). Such turbidities like the warm water are generally lethal to salmonids.<\/p>\n\n\n\n Figure 1.\u00a0 Upper Klamath River flow at Iron Gate gage in June and early July 2024.<\/p>\n\n\n\n Figure 2. Lower Klamath River gauging stations from Klamath Lake downstream to mouth. Blue marker denotes gage below JCBoyle Dam. Numbers in green and yellow circles denote multiple gage locations.<\/p>\n\n\n\n Figure 3. Water temperatures in lower Klamath River in June 2024. Iron Gate Dam is uppermost location and Turwar Gage is lower-most location near mouth. Note greatest water temperatures were recorded from the two uppermost reaches: Iron Gate and Walker Bridge.<\/p>\n\n\n\n Figure 4. Water temperature recorded at Iron Gate gage 6\/15-7\/7 2024.<\/p>\n\n\n\n Figure 5. Water temperature recorded at Walker Bridge gage 5\/20-7\/7 2024.<\/p>\n\n\n\n Figure 6. Water temperature recorded at Fall Creek gage 6\/1-7\/7 2024.<\/p>\n\n\n\n Figure 7. Water temperatures in lower Klamath River in June-July 2022. Iron Gate Dam is uppermost location and Turwar Gage is lower-most location near mouth. Note lowest water temperatures were recorded from the two uppermost reaches: Iron Gate and Walker Bridge.<\/p>\n\n\n\n Figure 8. \u00a0Water temperatures in lower Klamath River in June-July 2023.\u00a0 Iron Gate Dam is uppermost location and\u00a0Turwar\u00a0Gage is lower-most location near mouth.\u00a0 Note\u00a0lowest\u00a0water temperatures were recorded from uppermost reach: below Iron Gate.<\/p>\n\n\n\n Figure 9. Turbidity (suspended sediment) concentrations measured at Iron Gate Gage in 2024. Note original reservoir drawdown and subsequent reservoir sediment deposit erosion January-<\/p>\n","protected":false},"excerpt":{"rendered":" It is the first summer without the reservoirs on the Klamath River. Upper river flows at Iron Gate are now at summer lows (900 cfs, Figure 1). The flow, water temperature, and turbidity in the river without the reservoirs (the … Continue reading ![\"\"](\"https:\/\/calsport.org\/fisheriesblog\/wp-content\/uploads\/2024\/07\/image-22.png\")
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