Cotton Valley Water Recycling Ctr

Storm overflow run by Anglian Water, discharging into River Great Ouse/river Ouzel.

Storm tank at sewage treatment works Milton Keynes North constituency
Right now
No live feed
Anglian Water does not publish a live status for this overflow; only the annual figures below are available.

"Not discharging" means the company's monitor reports no discharge right now — not that the water is clean. The feed publishes status only; no discharge volume is measured.

2026 so far
1spill
0 h discharging on 1 day · counted by us, not yet official
2025 official
2spills
16 h · −93% on 2024
Rank in Anglian Water
#952
of 1,428 overflows by 2025 spills (1 = most)
Monitor in 2025
100% working
Long-term average 10.2 spills a year

Year by year

The Environment Agency's official annual returns, counted the EA's way (12/24-hour spills). 2026 is our own running count, the same way, from Anglian Water's monitor log. The official figure is published next spring.

2021
10 spills · 69 hmonitor 100%
2022
1 spill · 0.5 hmonitor 100%
2023
8 spills · 75 hmonitor 100%
2024
30 spills · 362 hmonitor 100%
2025
2 spills · 16 hmonitor 100%
2026so far
1 spill · 0 h

A spill is the EA's 12/24-hour count: the first 12 hours of a discharge count as one, each further 24 hours with discharge as one more. "Monitor" is the share of that year the monitor was working, so a 0 beside a working monitor is a real zero; "no data" means the monitor produced no usable data that year — not zero. Years before 2024 are matched to this site by name and location, because the EA's site IDs changed that year; a monitor figure beside one of them means the outlet's permit confirms the match.

Downstream of this overflow

The next gauge downstream that the river map places is Olney (River Great Ouse), 11.2 km along the river.

Water-sampling points downstream

The nearest Environment Agency sampling points the river map places below Olney. Points between this overflow and that gauge cannot be put in order with it on the map, so they are not listed.

A sample is dated: it is not the river now, and its results are on its own page. A sample taken after a discharge does not show that the discharge caused what was measured. Samples: Environment Agency Water Quality Archive, © Environment Agency and/or database right 2026, Open Government Licence v3.0.

A river gauge measures the level of the river; it does not measure this overflow's discharge, and a spill does not by itself explain a change there. Traced on OS Open Rivers (edition 2026-04), which leaves out many small channels.

Contains OS data © Crown copyright and database rights 2026.

What the 2025 return says

From Anglian Water's annual return to the Environment Agency for this overflow.

High-spill review
High spill threshold not met
Investigation
Env Act (SODRP) investigation ongoing
Improvement work
No improvement action in reporting period
Monitored since
2020
Water body
Ouse (Newport Pagnell to Roxton)

"High spill threshold not met" means this overflow did not spill often enough to trigger the EA's formal high-spill review for that year. It is not a statement that the spills were harmless.

Discharges we have recorded

26 discharge periods since 1 Jan 2024. 26 of them come from Anglian Water's own event-duration-monitoring records (published on Stream, Jan 2024 – Jan 2026); this overflow has no live feed, so nothing after that log is held. The official annual count is the figure to quote.

Show 16 earlier
StartedEndedDischarge time
13 h 15 min
1 d 11 h
2 d 17 h
1 h 0 min
4 h 0 min
1 d 5 h
10 h 15 min
12 h 15 min
20 h 15 min
14 h 0 min
1 d 20 h
4 h 0 min
1 d 7 h
21 h 15 min
8 h 0 min
6 h 30 min

The year figures above use the EA's 12/24-hour counting method, so they are comparable with the official figures; the monitor log's 46 raw blocks were merged into 26 continuous discharge periods (gaps under 15 min joined).

Rain nearby last 30 days

Nearest live rain gauge: Rainfall gauge nr Olney, 7.4 km away. Brown shading = when this overflow was discharging; ▼ = a discharge start.

Overflow shading is a timing match, not proof of cause — heavy rain and spills share a trigger. Times come from the water company’s event-duration monitor (site status only; no discharge volume is published).

Where it is

Nearest river gauge
Newport Pagnell (River Great Ouse) · 1.2 km
Nearest rain gauge
Council area
Milton Keynes (B)
Anglian Water's own name for it
Cotton Valley STW
Site reference
AWS00284 · permit AWCNF10296
Coordinates
52.09823, -0.71076

Concerned about this overflow?

Report pollution you can see or smell to the regulator straight away; the company handles complaints about the overflow itself.

Write to the MP

The Environment Agency's return places this overflow in the Milton Keynes North constituency. An MP can ask the company and the regulator questions on a constituent's behalf. These words carry the official figures; change them as you like.

The link opens Parliament's own "Find your MP", which gives the MP's name and how to write to them. FloodRadar sends nothing and keeps nothing you write. Check the constituency against your own address: an MP acts only for people who live in it.

Annual spill figures: Environment Agency Event Duration Monitoring return, © Environment Agency copyright and/or database right, Open Government Licence (OGL) v3.0. Storm-overflow spill events: © the respective water company, published on Stream (data.streamwaterdata.co.uk) under CC BY 4.0. Discharges marked "EA start/stop data": Environment Agency Event Duration Monitoring storm overflow start/stop detailed data, © Environment Agency copyright and/or database right 2026, Open Government Licence v3.0; the companies' monitor records as the EA received them, not verified by the EA. Times are shown in UK local time. FloodRadar republishes the monitor's status and the EA's figures; it does not measure discharges itself. Constituency and council area from the EA's return: contains OS data © Crown copyright and database right 2026.