COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-09-06 08:13 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-09-07 00:00 | 1277.76 | 2026-09-07 11:00 | 1277.94 |
| 2026-09-06 00:00 | 1277.43 | 2026-09-07 17:00 | 1278.01 |
| 2026-09-05 00:00 | 1277.17 | 2026-09-07 23:00 | 1278.09 |
| 2026-09-04 00:00 | 1276.76 | 2026-09-08 05:00 | 1278.17 |
| 2026-09-03 00:00 | 1276.64 | 2026-09-08 11:00 | 1278.25 |
| 2026-09-02 00:00 | 1276.78 | 2026-09-08 17:00 | 1278.33 |
| 2026-09-01 00:00 | 1277.43 | 2026-09-08 23:00 | 1278.41 |
| 2026-08-31 00:00 | 1277.5 | 2026-09-09 05:00 | 1278.49 |
| 2026-08-30 00:00 | 1277.4 | 2026-09-09 11:00 | 1278.57 |
| 2026-08-29 00:00 | 1277.27 | 2026-09-09 17:00 | 1278.65 |
| 2026-08-28 00:00 | 1277.34 | 2026-09-09 23:00 | 1278.74 |
| 2026-09-10 05:00 | 1278.82 | ||
| 2026-09-10 11:00 | 1278.9 | ||
| 2026-09-10 17:00 | 1278.98 | ||
| 2026-09-10 23:00 | 1279.05 | ||
| 2026-09-11 05:00 | 1279.13 | ||
| 2026-09-11 11:00 | 1279.2 | ||
| 2026-09-11 17:00 | 1279.26 | ||
| 2026-09-11 23:00 | 1279.32 | ||
| 2026-09-12 05:00 | 1279.37 | ||
| 2026-09-12 11:00 | 1279.42 | ||
| 2026-09-12 17:00 | 1279.47 | ||
| 2026-09-12 23:00 | 1279.51 | ||
| 2026-09-13 05:00 | 1279.56 | ||
| 2026-09-13 11:00 | 1279.61 | ||
| 2026-09-13 17:00 | 1279.65 | ||
| 2026-09-13 23:00 | 1279.7 | ||
| 2026-09-14 05:00 | 1279.76 | ||
| 2026-09-14 11:00 | 1279.83 | ||
| 2026-09-14 17:00 | 1279.9 | ||
| 2026-09-14 23:00 | 1279.98 | ||
| 2026-09-15 05:00 | 1280.05 | ||
| 2026-09-15 11:00 | 1280.11 | ||
| 2026-09-15 17:00 | 1280.18 | ||
| 2026-09-15 23:00 | 1280.24 | ||
| 2026-09-16 05:00 | 1280.31 | ||