Overflow history upstream of River Avon at Queen Elizabeth Gardens
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 | 14 | 750 | 6,892 | 304 |
| 2022 | 16 | 556 | 4,200 | 103 |
| 2023 | 18 | 1,181 | 14,237 | 1,133 |
| 2024 | 18 | 1,376 | 17,638 | 1,662 |
| 2025 | 19 | 617 | 6,616 | 437 |
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 21, 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 |
|---|---|---|---|---|---|---|---|---|---|
| Wishford Wilton Road storm tank overflow Wishford Wilton Road Storm Tank · WXW00481 | Wessex Water | 9.0 | 5 | 28% | 122 | 109 | 10 | 190 | 100% |
| Barford St Martin Burcombe storm tank overflow Barford ST Martin Burcombe Storm Tank · WXW00104 | Wessex Water | 11.5 | 6 | 20% | 122 | 185 | 81 | 1,551 | 100% |
| Barford ST Martin WXW00103 | Wessex Water | 11.9 | 7 | 18% | 11 | 23 | 4 | 42 | 100% |
| Hanging Langford WXW00498 | Wessex Water | 16.8 | 9 | 14% | 170 | 191 | 84 | 242 | 100% |
| Tisbury Nadder Close Playing Fields WXW01139 | Wessex Water | 28.6 | 16 | 4% | 52 | 56 | 36 | 71 | 100% |
| Amesbury Off Church Street storm tank overflow Amesbury OFF Church Street Storm Tank · WXW00081 | Wessex Water | 18.4 | 10 | 2% | 3 | 2 | 1 | 2 | 100% |
| Warminster storm tank overflow Warminster Storm Tank · WXW01192 | Wessex Water | 41.1 | 23 | 1% | 38 | 33 | 18 | 238 | 100% |
| WSX10174 WSX10174 | Wessex Water | 35.1 | 20 | 1% | – | – | – | – | – |
| Amesbury Flower Lane WXW00434 | Wessex Water | 19.7 | 11 | 1% | 0 | 0 | 0 | 0 | 100% |
| Fovant storm tank overflow Fovant Storm Tank · WXW00443 | Wessex Water | 20.8 | 12 | 1% | 139 | 193 | 81 | 1,252 | 100% |
| Shrewton storm tank overflow Shrewton Storm Tank · WXW00993 | Wessex Water | 22.7 | 13 | 1% | 262 | 235 | 116 | 2,679 | 100% |
| Warminster Calveswater WXW00224 | Wessex Water | 40.0 | 22 | 1% | 45 | 54 | 22 | 51 | 100% |
| Chilmark WXW00273 | Wessex Water | 25.4 | 14 | 1% | 0 | 27 | 7 | 101 | 100% |
| Warminster Weymouth Street R/O 23 IN Pleasure Gardens Near Swimming Pool WXW00610 | Wessex Water | 41.2 | 23 | 1% | 75 | 66 | 45 | 55 | 100% |
| Warminster, Weymouth Street R/O 23 storm overflow Warminster - Weymouth Street R/O 23 - Combined Sewer Overflow · WXW01354 | Wessex Water | 41.2 | 23 | 1% | – | – | 14 | 5 | 100% |
| Warminster George ST WXW00460 | Wessex Water | 41.3 | 23 | 1% | 0 | 8 | 3 | 1 | 100% |
| Hindon Inlet WXW00545 | Wessex Water | 32.6 | 18 | <1% | 113 | 129 | 74 | 97 | 100% |
| Semley Inlet WXW00974 | Wessex Water | 39.7 | 22 | <1% | 15 | 24 | 17 | 39 | 100% |
| Hindon THE Dene WXW00544 | Wessex Water | 32.6 | 18 | <1% | 14 | 41 | 4 | 2 | 100% |
| WSX10086 WSX10086 | Wessex Water | 49.1 | 27 | <1% | – | – | – | – | – |
| Monkton Deverill Hindon Road storm tank overflow Monkton Deverill Hindon Road Storm Tank · WXW00748 | Wessex Water | 49.3 | 27 | <1% | 0 | 0 | 0 | 0 | 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.