| 年度 | 大当別川橋(㎎／l) | 茂辺地川鮭見橋(㎎／l) | 流渓川橋(㎎／l) | 戸切地川戸切地橋(㎎／l) | 大野川有川橋(㎎／l) | 久根別川新久根別橋(㎎／l) | 常盤川臨港橋(㎎／l) |
| 2017 | 0.5 | 0.5 | 0.6 | 0.7 | 0.6 | 1.8 | 0.9 |
| 2018 | 0.5 | 0.5 | 0.5 | 0.6 | 0.9 | 1.2 | 1.4 |
| 2019 | 0.5 | 0.5 | 0.6 | 0.9 | 0.9 | 2 | 1.4 |
| 2020 | 0.5 | 0.6 | 0.6 | 0.6 | 0.7 | 2.1 | 2.1 |
| 2021 | 0.9 | 0.6 | 0.6 | 0.7 | 0.7 | 1.7 | 1.8 |
| 2022 | 0.7 | 0.7 | 0.6 | 0.9 | 0.9 | 2.8 | 1.5 |
| 2023 | 0.7 | 0.5 | 0.8 | 0.9 | 0.9 | 2.3 | 1.8 |