COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-08-01 08:44 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-08-02 00:00 | 1284.44 | 2026-08-02 05:00 | 1284.14 |
| 2026-08-01 00:00 | 1285.01 | 2026-08-02 11:00 | 1284.03 |
| 2026-07-31 00:00 | 1285.45 | 2026-08-02 17:00 | 1283.92 |
| 2026-07-30 00:00 | 1285.69 | 2026-08-02 23:00 | 1283.81 |
| 2026-07-29 00:00 | 1285.89 | 2026-08-03 05:00 | 1283.71 |
| 2026-07-28 00:00 | 1286.37 | 2026-08-03 11:00 | 1283.6 |
| 2026-07-27 00:00 | 1286.63 | 2026-08-03 17:00 | 1283.49 |
| 2026-07-26 00:00 | 1286.83 | 2026-08-03 23:00 | 1283.39 |
| 2026-07-25 00:00 | 1287.5 | 2026-08-04 05:00 | 1283.28 |
| 2026-07-24 00:00 | 1287.9 | 2026-08-04 11:00 | 1283.17 |
| 2026-07-23 00:00 | 1288.07 | 2026-08-04 17:00 | 1283.07 |
| 2026-08-04 23:00 | 1282.96 | ||
| 2026-08-05 05:00 | 1282.86 | ||
| 2026-08-05 11:00 | 1282.75 | ||
| 2026-08-05 17:00 | 1282.65 | ||
| 2026-08-05 23:00 | 1282.54 | ||
| 2026-08-06 05:00 | 1282.43 | ||
| 2026-08-06 11:00 | 1282.33 | ||
| 2026-08-06 17:00 | 1282.22 | ||
| 2026-08-06 23:00 | 1282.11 | ||
| 2026-08-07 05:00 | 1282.01 | ||
| 2026-08-07 11:00 | 1281.9 | ||
| 2026-08-07 17:00 | 1281.79 | ||
| 2026-08-07 23:00 | 1281.69 | ||
| 2026-08-08 05:00 | 1281.6 | ||
| 2026-08-08 11:00 | 1281.52 | ||
| 2026-08-08 17:00 | 1281.45 | ||
| 2026-08-08 23:00 | 1281.37 | ||
| 2026-08-09 05:00 | 1281.3 | ||
| 2026-08-09 11:00 | 1281.22 | ||
| 2026-08-09 17:00 | 1281.15 | ||
| 2026-08-09 23:00 | 1281.08 | ||
| 2026-08-10 05:00 | 1281 | ||
| 2026-08-10 11:00 | 1280.93 | ||
| 2026-08-10 17:00 | 1280.85 | ||
| 2026-08-10 23:00 | 1280.78 | ||
| 2026-08-11 05:00 | 1280.71 | ||