COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-07-26 12:51 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-07-26 00:00 | 1286.83 | 2026-07-26 23:00 | 1286.73 |
| 2026-07-25 00:00 | 1287.5 | 2026-07-27 05:00 | 1286.65 |
| 2026-07-24 00:00 | 1287.9 | 2026-07-27 11:00 | 1286.57 |
| 2026-07-23 00:00 | 1288.07 | 2026-07-27 17:00 | 1286.49 |
| 2026-07-22 00:00 | 1288.42 | 2026-07-27 23:00 | 1286.41 |
| 2026-07-21 00:00 | 1288.46 | 2026-07-28 05:00 | 1286.33 |
| 2026-07-20 00:00 | 1288.58 | 2026-07-28 11:00 | 1286.25 |
| 2026-07-19 00:00 | 1288.69 | 2026-07-28 17:00 | 1286.16 |
| 2026-07-18 00:00 | 1288.76 | 2026-07-28 23:00 | 1286.08 |
| 2026-07-17 00:00 | 1288.57 | 2026-07-29 05:00 | 1286 |
| 2026-07-16 00:00 | 1288.56 | 2026-07-29 11:00 | 1285.92 |
| 2026-07-29 17:00 | 1285.84 | ||
| 2026-07-29 23:00 | 1285.75 | ||
| 2026-07-30 05:00 | 1285.67 | ||
| 2026-07-30 11:00 | 1285.59 | ||
| 2026-07-30 17:00 | 1285.51 | ||
| 2026-07-30 23:00 | 1285.43 | ||
| 2026-07-31 05:00 | 1285.35 | ||
| 2026-07-31 11:00 | 1285.27 | ||
| 2026-07-31 17:00 | 1285.2 | ||
| 2026-07-31 23:00 | 1285.1 | ||
| 2026-08-01 05:00 | 1285 | ||
| 2026-08-01 11:00 | 1284.89 | ||
| 2026-08-01 17:00 | 1284.79 | ||
| 2026-08-01 23:00 | 1284.69 | ||
| 2026-08-02 05:00 | 1284.59 | ||
| 2026-08-02 11:00 | 1284.49 | ||
| 2026-08-02 17:00 | 1284.39 | ||
| 2026-08-02 23:00 | 1284.29 | ||
| 2026-08-03 05:00 | 1284.19 | ||
| 2026-08-03 11:00 | 1284.09 | ||
| 2026-08-03 17:00 | 1283.98 | ||
| 2026-08-03 23:00 | 1283.88 | ||
| 2026-08-04 05:00 | 1283.78 | ||
| 2026-08-04 11:00 | 1283.67 | ||
| 2026-08-04 17:00 | 1283.57 | ||
| 2026-08-04 23:00 | 1283.46 | ||
| 2026-08-05 05:00 | 1283.35 | ||