COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-07-20 10:41 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-07-20 00:00 | 1288.58 | 2026-07-20 23:00 | 1288.34 |
| 2026-07-19 00:00 | 1288.69 | 2026-07-21 05:00 | 1288.29 |
| 2026-07-18 00:00 | 1288.76 | 2026-07-21 11:00 | 1288.23 |
| 2026-07-17 00:00 | 1288.57 | 2026-07-21 17:00 | 1288.18 |
| 2026-07-16 00:00 | 1288.56 | 2026-07-21 23:00 | 1288.13 |
| 2026-07-15 00:00 | 1288.55 | 2026-07-22 05:00 | 1288.07 |
| 2026-07-14 00:00 | 1288.74 | 2026-07-22 11:00 | 1288.02 |
| 2026-07-13 00:00 | 1288.98 | 2026-07-22 17:00 | 1287.97 |
| 2026-07-12 00:00 | 1289.15 | 2026-07-22 23:00 | 1287.91 |
| 2026-07-11 00:00 | 1289.21 | 2026-07-23 05:00 | 1287.86 |
| 2026-07-10 00:00 | 1289.11 | 2026-07-23 11:00 | 1287.8 |
| 2026-07-23 17:00 | 1287.75 | ||
| 2026-07-23 23:00 | 1287.69 | ||
| 2026-07-24 05:00 | 1287.63 | ||
| 2026-07-24 11:00 | 1287.58 | ||
| 2026-07-24 17:00 | 1287.52 | ||
| 2026-07-24 23:00 | 1287.46 | ||
| 2026-07-25 05:00 | 1287.41 | ||
| 2026-07-25 11:00 | 1287.35 | ||
| 2026-07-25 17:00 | 1287.29 | ||
| 2026-07-25 23:00 | 1287.23 | ||
| 2026-07-26 05:00 | 1287.18 | ||
| 2026-07-26 11:00 | 1287.12 | ||
| 2026-07-26 17:00 | 1287.05 | ||
| 2026-07-26 23:00 | 1286.99 | ||
| 2026-07-27 05:00 | 1286.93 | ||
| 2026-07-27 11:00 | 1286.86 | ||
| 2026-07-27 17:00 | 1286.8 | ||
| 2026-07-27 23:00 | 1286.73 | ||
| 2026-07-28 05:00 | 1286.66 | ||
| 2026-07-28 11:00 | 1286.59 | ||
| 2026-07-28 17:00 | 1286.52 | ||
| 2026-07-28 23:00 | 1286.45 | ||
| 2026-07-29 05:00 | 1286.38 | ||
| 2026-07-29 11:00 | 1286.31 | ||
| 2026-07-29 17:00 | 1286.24 | ||
| 2026-07-29 23:00 | 1286.17 | ||
| 2026-07-30 05:00 | 1286.1 | ||