COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-03-27 08:40 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-03-27 00:00 | 1251.61 | 2026-03-27 23:00 | 1251.65 |
| 2026-03-26 00:00 | 1251.53 | 2026-03-28 05:00 | 1251.66 |
| 2026-03-25 00:00 | 1251.74 | 2026-03-28 11:00 | 1251.68 |
| 2026-03-24 00:00 | 1251.73 | 2026-03-28 17:00 | 1251.69 |
| 2026-03-23 00:00 | 1251.93 | 2026-03-28 23:00 | 1251.71 |
| 2026-03-22 00:00 | 1251.82 | 2026-03-29 05:00 | 1251.72 |
| 2026-03-21 00:00 | 1251.96 | 2026-03-29 11:00 | 1251.74 |
| 2026-03-20 00:00 | 1252.4 | 2026-03-29 17:00 | 1251.75 |
| 2026-03-19 00:00 | 1252.69 | 2026-03-29 23:00 | 1251.77 |
| 2026-03-18 00:00 | 1252.73 | 2026-03-30 05:00 | 1251.78 |
| 2026-03-17 00:00 | 1252.78 | 2026-03-30 11:00 | 1251.8 |
| 2026-03-30 17:00 | 1251.81 | ||
| 2026-03-30 23:00 | 1251.83 | ||
| 2026-03-31 05:00 | 1251.84 | ||
| 2026-03-31 11:00 | 1251.86 | ||
| 2026-03-31 17:00 | 1251.87 | ||
| 2026-03-31 23:00 | 1251.89 | ||
| 2026-04-01 05:00 | 1251.9 | ||
| 2026-04-01 11:00 | 1251.92 | ||
| 2026-04-01 17:00 | 1251.93 | ||
| 2026-04-01 23:00 | 1251.95 | ||
| 2026-04-02 05:00 | 1251.97 | ||
| 2026-04-02 11:00 | 1251.98 | ||
| 2026-04-02 17:00 | 1252 | ||
| 2026-04-02 23:00 | 1252.01 | ||
| 2026-04-03 05:00 | 1252.03 | ||
| 2026-04-03 11:00 | 1252.04 | ||
| 2026-04-03 17:00 | 1252.06 | ||
| 2026-04-03 23:00 | 1252.07 | ||
| 2026-04-04 05:00 | 1252.09 | ||
| 2026-04-04 11:00 | 1252.1 | ||
| 2026-04-04 17:00 | 1252.12 | ||
| 2026-04-04 23:00 | 1252.13 | ||
| 2026-04-05 05:00 | 1252.15 | ||
| 2026-04-05 11:00 | 1252.16 | ||
| 2026-04-05 17:00 | 1252.18 | ||
| 2026-04-05 23:00 | 1252.19 | ||
| 2026-04-06 05:00 | 1252.21 | ||