COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-09-28 09:50 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-09-29 00:00 | 1285.69 | 2026-09-29 05:00 | 1285.56 |
| 2026-09-28 00:00 | 1285.48 | 2026-09-29 11:00 | 1285.55 |
| 2026-09-27 00:00 | 1285.44 | 2026-09-29 17:00 | 1285.54 |
| 2026-09-26 00:00 | 1285.18 | 2026-09-29 23:00 | 1285.54 |
| 2026-09-25 00:00 | 1284.81 | 2026-09-30 05:00 | 1285.53 |
| 2026-09-24 00:00 | 1284.55 | 2026-09-30 11:00 | 1285.52 |
| 2026-09-23 00:00 | 1284.08 | 2026-09-30 17:00 | 1285.51 |
| 2026-09-22 00:00 | 1283.63 | 2026-09-30 23:00 | 1285.5 |
| 2026-09-21 00:00 | 1283.33 | 2026-10-01 05:00 | 1285.52 |
| 2026-09-20 00:00 | 1283.11 | 2026-10-01 11:00 | 1285.54 |
| 2026-09-19 00:00 | 1282.65 | 2026-10-01 17:00 | 1285.56 |
| 2026-10-01 23:00 | 1285.58 | ||
| 2026-10-02 05:00 | 1285.6 | ||
| 2026-10-02 11:00 | 1285.62 | ||
| 2026-10-02 17:00 | 1285.64 | ||
| 2026-10-02 23:00 | 1285.66 | ||
| 2026-10-03 05:00 | 1285.68 | ||
| 2026-10-03 11:00 | 1285.7 | ||
| 2026-10-03 17:00 | 1285.72 | ||
| 2026-10-03 23:00 | 1285.74 | ||
| 2026-10-04 05:00 | 1285.76 | ||
| 2026-10-04 11:00 | 1285.78 | ||
| 2026-10-04 17:00 | 1285.8 | ||
| 2026-10-04 23:00 | 1285.82 | ||
| 2026-10-05 05:00 | 1285.84 | ||
| 2026-10-05 11:00 | 1285.86 | ||
| 2026-10-05 17:00 | 1285.88 | ||
| 2026-10-05 23:00 | 1285.9 | ||
| 2026-10-06 05:00 | 1285.92 | ||
| 2026-10-06 11:00 | 1285.94 | ||
| 2026-10-06 17:00 | 1285.96 | ||
| 2026-10-06 23:00 | 1285.98 | ||
| 2026-10-07 05:00 | 1286 | ||
| 2026-10-07 11:00 | 1286.02 | ||
| 2026-10-07 17:00 | 1286.04 | ||
| 2026-10-07 23:00 | 1286.06 | ||
| 2026-10-08 05:00 | 1286.08 | ||