COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend |
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2022-07-02 23:59 | 1285.29 | 2022-07-03 17:00 | 1285.81 |
| 2022-06-30 23:59 | 1285.24 | 2022-07-03 23:00 | 1285.92 |
| 2022-06-29 23:59 | 1285.32 | 2022-07-04 05:00 | 1286.02 |
| 2022-06-28 23:59 | 1285.16 | 2022-07-04 11:00 | 1286.13 |
| 2022-06-27 23:59 | 1285.15 | 2022-07-04 17:00 | 1286.23 |
| 2022-06-26 23:59 | 1285.26 | 2022-07-04 23:00 | 1286.34 |
| 2022-06-25 23:59 | 1285.27 | 2022-07-05 05:00 | 1286.47 |
| 2022-06-24 23:59 | 1285.25 | 2022-07-05 11:00 | 1286.6 |
| 2022-06-23 23:59 | 1285 | 2022-07-05 17:00 | 1286.73 |
| 2022-06-22 23:59 | 1284.68 | 2022-07-05 23:00 | 1286.87 |
| | | 2022-07-06 05:00 | 1287 |
| | | 2022-07-06 11:00 | 1287.13 |
| | | 2022-07-06 17:00 | 1287.26 |
| | | 2022-07-06 23:00 | 1287.39 |
| | | 2022-07-07 05:00 | 1287.52 |
| | | 2022-07-07 11:00 | 1287.66 |
| | | 2022-07-07 17:00 | 1287.79 |
| | | 2022-07-07 23:00 | 1287.92 |
| | | 2022-07-08 05:00 | 1288.05 |
| | | 2022-07-08 11:00 | 1288.18 |
| | | 2022-07-08 17:00 | 1288.32 |
| | | 2022-07-08 23:00 | 1288.45 |
| | | 2022-07-09 05:00 | 1288.58 |
| | | 2022-07-09 11:00 | 1288.71 |
| | | 2022-07-09 17:00 | 1288.84 |
| | | 2022-07-09 23:00 | 1288.97 |
| | | 2022-07-10 05:00 | 1289.11 |
| | | 2022-07-10 11:00 | 1289.24 |
| | | 2022-07-10 17:00 | 1289.37 |
| | | 2022-07-10 23:00 | 1289.5 |
| | | 2022-07-11 05:00 | 1289.5 |
| | | 2022-07-11 11:00 | 1289.5 |
| | | 2022-07-11 17:00 | 1289.5 |
| | | 2022-07-11 23:00 | 1289.5 |
| | | 2022-07-12 05:00 | 1289.5 |
| | | 2022-07-12 11:00 | 1289.5 |
| | | 2022-07-12 17:00 | 1289.5 |
| | | 2022-07-12 23:00 | 1289.5 |
| | | 2022-07-13 05:00 | 1289.5 |