COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-06-29 10:39 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-06-29 00:00 | 1285.92 | 2026-06-29 17:00 | 1286 |
| 2026-06-28 00:00 | 1285.37 | 2026-06-29 23:00 | 1286 |
| 2026-06-27 00:00 | 1285 | 2026-06-30 05:00 | 1286 |
| 2026-06-26 00:00 | 1285.19 | 2026-06-30 11:00 | 1286 |
| 2026-06-25 00:00 | 1285.39 | 2026-06-30 17:00 | 1286 |
| 2026-06-24 00:00 | 1285.23 | 2026-06-30 23:00 | 1286 |
| 2026-06-23 00:00 | 1285.1 | 2026-07-01 05:00 | 1286 |
| 2026-06-22 00:00 | 1284.66 | 2026-07-01 11:00 | 1286 |
| 2026-06-21 00:00 | 1283.69 | 2026-07-01 17:00 | 1286 |
| 2026-06-20 00:00 | 1282.98 | 2026-07-01 23:00 | 1286 |
| 2026-06-19 00:00 | 1282.95 | 2026-07-02 05:00 | 1286.06 |
| 2026-07-02 11:00 | 1286.13 | ||
| 2026-07-02 17:00 | 1286.19 | ||
| 2026-07-02 23:00 | 1286.25 | ||
| 2026-07-03 05:00 | 1286.31 | ||
| 2026-07-03 11:00 | 1286.38 | ||
| 2026-07-03 17:00 | 1286.44 | ||
| 2026-07-03 23:00 | 1286.5 | ||
| 2026-07-04 05:00 | 1286.56 | ||
| 2026-07-04 11:00 | 1286.63 | ||
| 2026-07-04 17:00 | 1286.69 | ||
| 2026-07-04 23:00 | 1286.75 | ||
| 2026-07-05 05:00 | 1286.81 | ||
| 2026-07-05 11:00 | 1286.88 | ||
| 2026-07-05 17:00 | 1286.94 | ||
| 2026-07-05 23:00 | 1287 | ||
| 2026-07-06 05:00 | 1287.09 | ||
| 2026-07-06 11:00 | 1287.2 | ||
| 2026-07-06 17:00 | 1287.29 | ||
| 2026-07-06 23:00 | 1287.38 | ||
| 2026-07-07 05:00 | 1287.46 | ||
| 2026-07-07 11:00 | 1287.54 | ||
| 2026-07-07 17:00 | 1287.61 | ||
| 2026-07-07 23:00 | 1287.68 | ||
| 2026-07-08 05:00 | 1287.74 | ||
| 2026-07-08 11:00 | 1287.8 | ||
| 2026-07-08 17:00 | 1287.85 | ||
| 2026-07-08 23:00 | 1287.9 | ||
| 2026-07-09 05:00 | 1287.95 | ||