COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-08-10 10:29 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-08-10 00:00 | 1282.83 | 2026-08-11 05:00 | 1282.69 |
| 2026-08-09 00:00 | 1283 | 2026-08-11 11:00 | 1282.64 |
| 2026-08-08 00:00 | 1283.34 | 2026-08-11 17:00 | 1282.59 |
| 2026-08-07 00:00 | 1283.62 | 2026-08-11 23:00 | 1282.54 |
| 2026-08-06 00:00 | 1283.81 | 2026-08-12 05:00 | 1282.5 |
| 2026-08-05 00:00 | 1284.03 | 2026-08-12 11:00 | 1282.46 |
| 2026-08-04 00:00 | 1284.21 | 2026-08-12 17:00 | 1282.42 |
| 2026-08-03 00:00 | 1284.36 | 2026-08-12 23:00 | 1282.38 |
| 2026-08-02 00:00 | 1284.44 | 2026-08-13 05:00 | 1282.34 |
| 2026-08-01 00:00 | 1285.01 | 2026-08-13 11:00 | 1282.3 |
| 2026-07-31 00:00 | 1285.45 | 2026-08-13 17:00 | 1282.26 |
| 2026-08-13 23:00 | 1282.21 | ||
| 2026-08-14 05:00 | 1282.16 | ||
| 2026-08-14 11:00 | 1282.1 | ||
| 2026-08-14 17:00 | 1282.04 | ||
| 2026-08-14 23:00 | 1281.98 | ||
| 2026-08-15 05:00 | 1281.92 | ||
| 2026-08-15 11:00 | 1281.85 | ||
| 2026-08-15 17:00 | 1281.79 | ||
| 2026-08-15 23:00 | 1281.72 | ||
| 2026-08-16 05:00 | 1281.66 | ||
| 2026-08-16 11:00 | 1281.6 | ||
| 2026-08-16 17:00 | 1281.54 | ||
| 2026-08-16 23:00 | 1281.48 | ||
| 2026-08-17 05:00 | 1281.43 | ||
| 2026-08-17 11:00 | 1281.37 | ||
| 2026-08-17 17:00 | 1281.32 | ||
| 2026-08-17 23:00 | 1281.26 | ||
| 2026-08-18 05:00 | 1281.21 | ||
| 2026-08-18 11:00 | 1281.15 | ||
| 2026-08-18 17:00 | 1281.1 | ||
| 2026-08-18 23:00 | 1281.04 | ||
| 2026-08-19 05:00 | 1280.99 | ||
| 2026-08-19 11:00 | 1280.93 | ||
| 2026-08-19 17:00 | 1280.88 | ||
| 2026-08-19 23:00 | 1280.82 | ||
| 2026-08-20 05:00 | 1280.77 | ||