COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-07-08 09:19 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-07-08 00:00 | 1288.3 | 2026-07-08 17:00 | 1288.85 |
| 2026-07-07 00:00 | 1287.59 | 2026-07-08 23:00 | 1288.87 |
| 2026-07-06 00:00 | 1286.88 | 2026-07-09 05:00 | 1288.89 |
| 2026-07-05 00:00 | 1286.51 | 2026-07-09 11:00 | 1288.91 |
| 2026-07-04 00:00 | 1286.25 | 2026-07-09 17:00 | 1288.93 |
| 2026-07-03 00:00 | 1285.87 | 2026-07-09 23:00 | 1288.96 |
| 2026-07-02 00:00 | 1285.6 | 2026-07-10 05:00 | 1288.98 |
| 2026-07-01 00:00 | 1285.76 | 2026-07-10 11:00 | 1289 |
| 2026-06-30 00:00 | 1285.92 | 2026-07-10 17:00 | 1289.06 |
| 2026-06-29 00:00 | 1285.92 | 2026-07-10 23:00 | 1289.11 |
| 2026-06-28 00:00 | 1285.37 | 2026-07-11 05:00 | 1289.17 |
| 2026-07-11 11:00 | 1289.23 | ||
| 2026-07-11 17:00 | 1289.29 | ||
| 2026-07-11 23:00 | 1289.34 | ||
| 2026-07-12 05:00 | 1289.4 | ||
| 2026-07-12 11:00 | 1289.45 | ||
| 2026-07-12 17:00 | 1289.49 | ||
| 2026-07-12 23:00 | 1289.52 | ||
| 2026-07-13 05:00 | 1289.55 | ||
| 2026-07-13 11:00 | 1289.58 | ||
| 2026-07-13 17:00 | 1289.59 | ||
| 2026-07-13 23:00 | 1289.59 | ||
| 2026-07-14 05:00 | 1289.59 | ||
| 2026-07-14 11:00 | 1289.58 | ||
| 2026-07-14 17:00 | 1289.56 | ||
| 2026-07-14 23:00 | 1289.54 | ||
| 2026-07-15 05:00 | 1289.52 | ||
| 2026-07-15 11:00 | 1289.49 | ||
| 2026-07-15 17:00 | 1289.46 | ||
| 2026-07-15 23:00 | 1289.42 | ||
| 2026-07-16 05:00 | 1289.38 | ||
| 2026-07-16 11:00 | 1289.34 | ||
| 2026-07-16 17:00 | 1289.3 | ||
| 2026-07-16 23:00 | 1289.25 | ||
| 2026-07-17 05:00 | 1289.19 | ||
| 2026-07-17 11:00 | 1289.14 | ||
| 2026-07-17 17:00 | 1289.08 | ||
| 2026-07-17 23:00 | 1289.01 | ||
| 2026-07-18 05:00 | 1288.95 | ||