COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-07-11 09:05 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-07-11 00:00 | 1289.21 | 2026-07-11 17:00 | 1289.3 |
| 2026-07-10 00:00 | 1289.11 | 2026-07-11 23:00 | 1289.35 |
| 2026-07-09 00:00 | 1288.84 | 2026-07-12 05:00 | 1289.4 |
| 2026-07-08 00:00 | 1288.3 | 2026-07-12 11:00 | 1289.41 |
| 2026-07-07 00:00 | 1287.59 | 2026-07-12 17:00 | 1289.39 |
| 2026-07-06 00:00 | 1286.88 | 2026-07-12 23:00 | 1289.36 |
| 2026-07-05 00:00 | 1286.51 | 2026-07-13 05:00 | 1289.33 |
| 2026-07-04 00:00 | 1286.25 | 2026-07-13 11:00 | 1289.31 |
| 2026-07-03 00:00 | 1285.87 | 2026-07-13 17:00 | 1289.29 |
| 2026-07-02 00:00 | 1285.6 | 2026-07-13 23:00 | 1289.28 |
| 2026-07-01 00:00 | 1285.76 | 2026-07-14 05:00 | 1289.27 |
| 2026-07-14 11:00 | 1289.25 | ||
| 2026-07-14 17:00 | 1289.23 | ||
| 2026-07-14 23:00 | 1289.21 | ||
| 2026-07-15 05:00 | 1289.17 | ||
| 2026-07-15 11:00 | 1289.14 | ||
| 2026-07-15 17:00 | 1289.09 | ||
| 2026-07-15 23:00 | 1289.05 | ||
| 2026-07-16 05:00 | 1289 | ||
| 2026-07-16 11:00 | 1288.95 | ||
| 2026-07-16 17:00 | 1288.9 | ||
| 2026-07-16 23:00 | 1288.85 | ||
| 2026-07-17 05:00 | 1288.79 | ||
| 2026-07-17 11:00 | 1288.74 | ||
| 2026-07-17 17:00 | 1288.68 | ||
| 2026-07-17 23:00 | 1288.63 | ||
| 2026-07-18 05:00 | 1288.57 | ||
| 2026-07-18 11:00 | 1288.52 | ||
| 2026-07-18 17:00 | 1288.46 | ||
| 2026-07-18 23:00 | 1288.4 | ||
| 2026-07-19 05:00 | 1288.34 | ||
| 2026-07-19 11:00 | 1288.27 | ||
| 2026-07-19 17:00 | 1288.21 | ||
| 2026-07-19 23:00 | 1288.14 | ||
| 2026-07-20 05:00 | 1288.07 | ||
| 2026-07-20 11:00 | 1288 | ||
| 2026-07-20 17:00 | 1287.92 | ||
| 2026-07-20 23:00 | 1287.85 | ||
| 2026-07-21 05:00 | 1287.77 | ||