COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-07-17 09:54 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-07-17 00:00 | 1288.57 | 2026-07-17 23:00 | 1288.56 |
| 2026-07-16 00:00 | 1288.56 | 2026-07-18 05:00 | 1288.47 |
| 2026-07-15 00:00 | 1288.55 | 2026-07-18 11:00 | 1288.38 |
| 2026-07-14 00:00 | 1288.74 | 2026-07-18 17:00 | 1288.28 |
| 2026-07-13 00:00 | 1288.98 | 2026-07-18 23:00 | 1288.19 |
| 2026-07-12 00:00 | 1289.15 | 2026-07-19 05:00 | 1288.09 |
| 2026-07-11 00:00 | 1289.21 | 2026-07-19 11:00 | 1288 |
| 2026-07-10 00:00 | 1289.11 | 2026-07-19 17:00 | 1287.9 |
| 2026-07-09 00:00 | 1288.84 | 2026-07-19 23:00 | 1287.81 |
| 2026-07-08 00:00 | 1288.3 | 2026-07-20 05:00 | 1287.72 |
| 2026-07-07 00:00 | 1287.59 | 2026-07-20 11:00 | 1287.62 |
| 2026-07-20 17:00 | 1287.53 | ||
| 2026-07-20 23:00 | 1287.44 | ||
| 2026-07-21 05:00 | 1287.34 | ||
| 2026-07-21 11:00 | 1287.24 | ||
| 2026-07-21 17:00 | 1287.15 | ||
| 2026-07-21 23:00 | 1287.05 | ||
| 2026-07-22 05:00 | 1286.95 | ||
| 2026-07-22 11:00 | 1286.85 | ||
| 2026-07-22 17:00 | 1286.75 | ||
| 2026-07-22 23:00 | 1286.65 | ||
| 2026-07-23 05:00 | 1286.54 | ||
| 2026-07-23 11:00 | 1286.44 | ||
| 2026-07-23 17:00 | 1286.34 | ||
| 2026-07-23 23:00 | 1286.23 | ||
| 2026-07-24 05:00 | 1286.13 | ||
| 2026-07-24 11:00 | 1286.02 | ||
| 2026-07-24 17:00 | 1285.91 | ||
| 2026-07-24 23:00 | 1285.81 | ||
| 2026-07-25 05:00 | 1285.7 | ||
| 2026-07-25 11:00 | 1285.59 | ||
| 2026-07-25 17:00 | 1285.48 | ||
| 2026-07-25 23:00 | 1285.37 | ||
| 2026-07-26 05:00 | 1285.26 | ||
| 2026-07-26 11:00 | 1285.15 | ||
| 2026-07-26 17:00 | 1285.04 | ||
| 2026-07-26 23:00 | 1284.93 | ||
| 2026-07-27 05:00 | 1284.81 | ||