The five Bureau of Reclamation storage reservoirs on the Yakima River held 264 million cubic metres on 29 September 2026, 20.1% of capacity — about 214,000 acre-feet. On 29 September 2025 the same five held 115 million cubic metres, 8.8%. On 29 September 2022 they held 533 million cubic metres, 40.5%.
Key takeaways
- The five Yakima reservoirs are 20.1% full. They hold 264 million cubic metres, 2.3 times the volume of 29 September 2025 and half the volume of 29 September 2022.
- Rimrock and Kachess hold the gain. Together they stored 204 million cubic metres, against 73 million a year ago. Rimrock, at 43.5%, is close to its 2022 level of 46.9%.
- Cle Elum is the largest reservoir, and it is at 6.4%. It held 34 million cubic metres of a 539 million cubic metre capacity. Keechelus was at 7.5%.
- Drawdown ran through the last two weeks of the month. From 14 to 29 September the five lost 75 million cubic metres. Rimrock lost 40 million of that.
Same day, six years
Keechelus, Kachess and Cle Elum store the upper Yakima. Bumping Lake stores the Bumping River, and Rimrock, behind Tieton Dam, stores the Tieton. Those two rivers meet the Naches, which meets the Yakima. Each figure below is the reading nearest 29 September. In 2026, Keechelus is 28 September and the other four are 29 September. The series begins on 1 October 2021, so that year is two days later.
| Late September |
Stored |
Fill |
| 2026 |
264 MCM |
20.1% |
| 2025 |
115 MCM |
8.8% |
| 2024 |
145 MCM |
11.1% |
| 2023 |
168 MCM |
12.8% |
| 2022 |
533 MCM |
40.5% |
| 2021 (1 Oct) |
433 MCM |
33.0% |
From 2022 to 2023 the five lost 365 million cubic metres. The next three Septembers stayed between 115 and 168. This year puts back 149 million cubic metres of the 2022 storage. The gap that remains is 269 million cubic metres.
| Reservoir |
Capacity |
29 Sep 2026 |
29 Sep 2025 |
29 Sep 2022 |
| Cle Elum |
539 MCM |
6.4% |
3.8% |
31.4% |
| Kachess |
295 MCM |
33.1% |
12.3% |
58.1% |
| Rimrock |
244 MCM |
43.5% |
15.2% |
46.9% |
| Keechelus |
195 MCM |
7.5% |
6.4% |
31.7% |
| Bumping |
42 MCM |
27.0% |
22.1% |
39.0% |
| Five reservoirs |
1,315 MCM |
20.1% |
8.8% |
40.5% |
Capacities are rounded to the nearest million cubic metres. Fill is storage divided by the unrounded capacity, so the total row is capacity-weighted. Keechelus's 2026 figure is its 28 September reading.
Where the extra water sits
Rimrock held 106 million cubic metres and Kachess 98 million. A year ago those two held 37 million and 36 million. Of the 149 million cubic metres added since September 2025, 131 million are in these two lakes.
Rimrock is the reservoir that has come back to its 2022 late-September level: 43.5%, against 46.9%. Kachess has risen from 12.3% to 33.1%, and 33.1% is still 25 points under the 58.1% of 2022.
Cle Elum held 34 million cubic metres, against 20 million a year ago and 169 million in 2022. Of the 269 million cubic metres that separate this September from 2022, 135 million are water Cle Elum is not holding. Keechelus held 15 million cubic metres, against 12 million last year and 62 million in 2022. Bumping held 11 million. A reservoir of 42 million cubic metres of capacity does not move the five-lake total.
On 11 August, Cle Elum was at 25.2%. The summer movers roundup left it off the list of unusual swings because that level sat on its August norm. The reading that places 2026 is the one six weeks later. At 6.4% on 29 September, Cle Elum matches the 3.8% to 4.5% range of late September 2023, 2024 and 2025. On this date in 2022 it was at 31.4%, and on 1 October 2021 it was at 21.4%.
The last two weeks were still a release
On 14 September the five held 339 million cubic metres. By 29 September they held 264 million. Rimrock went from 60% to 43.5%, a loss of 40 million cubic metres. Kachess went from 41.8% to 33.1%, a loss of 26 million. Cle Elum, Keechelus and Bumping together lost about 9 million.
The water year ends on 30 September. These figures are the storage at the end of a season that was still releasing water in its last fortnight. Carryover is what remains once those releases stop, and it is the balance the next irrigation season starts from. At 264 million cubic metres the starting balance is higher than in 2023, 2024 or 2025. It is half the balance of September 2022, and the empty capacity is concentrated in Cle Elum.
Refill on this river comes from snow in the Cascades. A late-September percentage does not describe the winter ahead. It describes the water already in the reservoirs.
A monthly average would blur that. These lakes drop inside September: Rimrock alone went from 60% to 43.5% in fifteen days. The comparison here is the same day of the year, within three days, for every year we hold. The source is the Bureau of Reclamation's daily storage record. The five reservoirs above are the Yakima storage lakes in that record. Live charts are on each reservoir page and on the Washington map.
The US September comparison put Washington 0.6 points from its recent September norm, across 13 reservoirs measured earlier in the month. That state figure takes in more than this basin. The Yakima number is the table above. How the Bureau feed is ingested is set out in How we get our data: United States, and US data openness is scored in the Reservoir Transparency Index.
