COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-07-23 09:24 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-07-23 00:00 | 1288.07 | 2026-07-23 23:00 | 1287.69 |
| 2026-07-22 00:00 | 1288.42 | 2026-07-24 05:00 | 1287.62 |
| 2026-07-21 00:00 | 1288.46 | 2026-07-24 11:00 | 1287.55 |
| 2026-07-20 00:00 | 1288.58 | 2026-07-24 17:00 | 1287.47 |
| 2026-07-19 00:00 | 1288.69 | 2026-07-24 23:00 | 1287.39 |
| 2026-07-18 00:00 | 1288.76 | 2026-07-25 05:00 | 1287.3 |
| 2026-07-17 00:00 | 1288.57 | 2026-07-25 11:00 | 1287.22 |
| 2026-07-16 00:00 | 1288.56 | 2026-07-25 17:00 | 1287.15 |
| 2026-07-15 00:00 | 1288.55 | 2026-07-25 23:00 | 1287.08 |
| 2026-07-14 00:00 | 1288.74 | 2026-07-26 05:00 | 1287.02 |
| 2026-07-13 00:00 | 1288.98 | 2026-07-26 11:00 | 1286.96 |
| 2026-07-26 17:00 | 1286.9 | ||
| 2026-07-26 23:00 | 1286.83 | ||
| 2026-07-27 05:00 | 1286.76 | ||
| 2026-07-27 11:00 | 1286.69 | ||
| 2026-07-27 17:00 | 1286.61 | ||
| 2026-07-27 23:00 | 1286.53 | ||
| 2026-07-28 05:00 | 1286.45 | ||
| 2026-07-28 11:00 | 1286.37 | ||
| 2026-07-28 17:00 | 1286.29 | ||
| 2026-07-28 23:00 | 1286.21 | ||
| 2026-07-29 05:00 | 1286.13 | ||
| 2026-07-29 11:00 | 1286.05 | ||
| 2026-07-29 17:00 | 1285.97 | ||
| 2026-07-29 23:00 | 1285.89 | ||
| 2026-07-30 05:00 | 1285.81 | ||
| 2026-07-30 11:00 | 1285.73 | ||
| 2026-07-30 17:00 | 1285.65 | ||
| 2026-07-30 23:00 | 1285.57 | ||
| 2026-07-31 05:00 | 1285.49 | ||
| 2026-07-31 11:00 | 1285.41 | ||
| 2026-07-31 17:00 | 1285.33 | ||
| 2026-07-31 23:00 | 1285.25 | ||
| 2026-08-01 05:00 | 1285.18 | ||
| 2026-08-01 11:00 | 1285.11 | ||
| 2026-08-01 17:00 | 1285.05 | ||
| 2026-08-01 23:00 | 1284.99 | ||
| 2026-08-02 05:00 | 1284.93 | ||