Overflow history upstream of River Wye, Bishop's Meadow, Hereford
The spot's forecast · For event organisers
This page lists the monitored storm overflows upstream of this spot and how often each spilled in each year. It is not a water test, and it does not say whether the water is fit to swim in. It does not include farm runoff, misconnected drains, treated sewage effluent, wildlife or overflows without a monitor. A year's count depends on how long the monitor worked, shown as monitor uptime.
Each year, all overflows upstream
| Year | Overflows with a return | Spills | Spill hours | Spill hours, weighted by reach |
|---|---|---|---|---|
| 2021 | 11 | 289 | 1,735 | 496 |
| 2022 | 11 | 304 | 1,731 | 510 |
| 2023 | 11 | 233 | 2,314 | 576 |
| 2024 | 14 | 429 | 4,711 | 743 |
| 2025 | 14 | 214 | 1,060 | 197 |
Reach is the share of a spill's bacteria SwimSignal's model expects to arrive here, after die-off on the way and dilution by the river. Weighting by it counts an hour of spilling just upstream for far more than one 40 km away. Spills are counted by the Environment Agency's 12/24 method: any discharge in the first 12 hours counts as one spill, then one more for each 24 hours with any discharge. How reach is worked out.
The overflows, by reach
All 14, the one whose spills matter most here first. Hours away is how long sewage takes to arrive at the model's river speed.
| Overflow and id | Company | km upstream | Hours away | Reach | Spills 2023 | Spills 2024 | Spills 2025 | Spill hours 2025 | Monitor uptime 2025 |
|---|---|---|---|---|---|---|---|---|---|
| Hereford Beneath Greyfriars Bridge DCW00055 | Dwr Cymru Welsh Water | 0.2 | under 1 | 90% | – | 41 | 15 | 32 | 93% |
| St Martins Allotments Hereford storm overflow St Martins Allotments CSO Hereford · DCW00109 | Dwr Cymru Welsh Water | 0.2 | under 1 | 90% | 30 | 43 | 31 | 96 | 100% |
| Hereford Belmont Roundabout DCW00016 | Dwr Cymru Welsh Water | 0.2 | under 1 | 90% | 39 | 28 | 9 | 51 | 94% |
| Hereford Cycle Track, Hereford storm overflow Hereford Cycle Track CSO, Hereford · DCW00128 | Dwr Cymru Welsh Water | 0.3 | under 1 | 90% | 15 | 2 | 1 | 4 | 100% |
| Whitecross Road storm overflow Whitecross Road CSO · DCW00122 | Dwr Cymru Welsh Water | 0.6 | under 1 | 89% | 1 | 8 | 2 | 1 | 100% |
| Hereford Broomy Hill/Belvedere Lane DCW00005 | Dwr Cymru Welsh Water | 0.7 | under 1 | 88% | 2 | 1 | 1 | 0 | 100% |
| Plough Lane Hereford storm overflow Plough Lane Hereford CSO · DCW00031 | Dwr Cymru Welsh Water | 1.2 | under 1 | 86% | – | 12 | 40 | 19 | 99% |
| Barton Road, Hereford storm overflow Barton Road CSO, Hereford · DCW00015 | Dwr Cymru Welsh Water | 0.3 | under 1 | 8% | – | 23 | 6 | 4 | 100% |
| Widemarsh Common Road, Hereford storm overflow Widemarsh Common Road CSO, Hereford · DCW00081 | Dwr Cymru Welsh Water | 1.1 | under 1 | 8% | 6 | 4 | 2 | 1 | 100% |
| Hereford Three Elms Road/Ferndale Road DCW00010 | Dwr Cymru Welsh Water | 2.1 | 1 | 8% | 8 | 10 | 24 | 12 | 98% |
| Hereford Three Elms Road/Oatfield Close DCW00118 | Dwr Cymru Welsh Water | 2.2 | 1 | 8% | 13 | 24 | 14 | 6 | 100% |
| Hereford Grandstand Road DCW00052 | Dwr Cymru Welsh Water | 2.7 | 2 | 7% | 9 | 10 | 11 | 4 | 99% |
| Eardisley sewage works overflow Eardisley WwTW · DCW00107 | Dwr Cymru Welsh Water | 33.2 | 18 | 2% | 78 | 108 | 37 | 530 | 94% |
| Moccas sewage works overflow Moccas WwTW · DCW00094 | Dwr Cymru Welsh Water | 21.8 | 12 | 1% | 32 | 115 | 21 | 301 | 100% |
A dash: no annual return for that overflow in that year.
Sources and credits
Storm overflow annual returns: © Environment Agency copyright and/or database right 2025, Open Government Licence v3.0. Overflow positions: the water companies via the National Storm Overflow Hub, CC BY 4.0. River network: contains OS data © Crown copyright and database right 2026 (OS Open Rivers). Traced and weighted by SwimSignal (swimsignal.co.uk), whose method is at swimsignal.co.uk/methods.html. All credits and licences.