River Ouse Castle Mills
EA name: R.OUSE CASTLE MILLS
Environment Agency sampling point AN-12M05 · Freshwater - rivers · listed as open (“open” does not mean it is sampled now)
These are samples taken on a date, not live readings of the river. Results reach the Environment Agency's archive days to months after the sample is taken, so the newest here may be weeks or months old. FloodRadar does not grade them.
Where and when
- Last sampled
- 3 Aug 2026, 12:1259 days ago · time as the Environment Agency records it (UK clock time; the source gives no time zone)
- Samples banked
- 30 since 5 Oct 2023 Imported periods: 1 Oct 2023 – 30 Sep 2026. Samples outside them are not shown here.
- Latest sample
- River / running surface water Monitoring (national agency policy)
- Where
- National Grid 509200, 250900As published, to the nearest 100 m (so up to about 70 m out). Open in a map
- River, by its own name
- Its name does not give one
- River, by the map
- Not placedGrid reference only to 100 m and no line carries the name it gives, so position alone cannot choose. The river map cannot say which watercourse this is.
- Next gauge downstream
- Not known
- Why it was sampled
- Monitoring (national agency policy) (24 samples)
Environmental monitoring statutory (EU directives) (6 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
97.3%
Sampled 3 Aug 2026, 59 days ago · 5 results banked
Every result (5)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Aug 2026, 12:12 | 97.3 | 97.3% |
| 2 Jul 2026, 10:52 | 95.6 | 95.6% |
| 4 Jun 2026, 12:15 | 76.7 | 76.7% |
| 21 May 2026, 09:45 | 98.7 | 98.7% |
| 23 Apr 2026, 12:08 | 100.3 | 100.3% |
Dissolved oxygen
as O2 · code 9924 · mg/l
8.49 mg/l
Sampled 3 Aug 2026, 59 days ago · 5 results banked
Every result (5)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Aug 2026, 12:12 | 8.49 | 8.49 mg/l |
| 2 Jul 2026, 10:52 | 8.37 | 8.37 mg/l |
| 4 Jun 2026, 12:15 | 7.17 | 7.17 mg/l |
| 21 May 2026, 09:45 | 9.91 | 9.91 mg/l |
| 23 Apr 2026, 12:08 | 10.5 | 10.5 mg/l |
Water temperature
code 0076 · °C
22 °C
Sampled 3 Aug 2026, 59 days ago · 5 results banked
Every result (5)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Aug 2026, 12:12 | 22 | 22 °C |
| 2 Jul 2026, 10:52 | 21.8 | 21.8 °C |
| 4 Jun 2026, 12:15 | 18.5 | 18.5 °C |
| 21 May 2026, 09:45 | 15.1 | 15.1 °C |
| 23 Apr 2026, 12:08 | 13.3 | 13.3 °C |
pH
code 0061
7.76
Sampled 3 Aug 2026, 59 days ago · 5 results banked
Every result (5)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Aug 2026, 12:12 | 7.76 | 7.76 |
| 2 Jul 2026, 10:52 | 7.82 | 7.82 |
| 4 Jun 2026, 12:15 | 7.87 | 7.87 |
| 21 May 2026, 09:45 | 8.12 | 8.12 |
| 23 Apr 2026, 12:08 | 8.04 | 8.04 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
0.2 mg/l
Sampled 3 Aug 2026, 59 days ago · 5 results banked
Every result (5)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Aug 2026, 12:12 | 0.2 | 0.2 mg/l |
| 2 Jul 2026, 10:52 | 0.5 | 0.5 mg/l |
| 4 Jun 2026, 12:15 | 0.3 | 0.3 mg/l |
| 21 May 2026, 09:45 | 0.25 | 0.25 mg/l |
| 23 Apr 2026, 12:08 | 0.45 | 0.45 mg/l |
Nitrate
as nitrogen (N) · code 0117 · mg/l
7.57 mg/l
Sampled 3 Aug 2026, 59 days ago · 5 results banked
Every result (5)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Aug 2026, 12:12 | 7.57 | 7.57 mg/l |
| 2 Jul 2026, 10:52 | 4.88 | 4.88 mg/l |
| 4 Jun 2026, 12:15 | 4.21 | 4.21 mg/l |
| 21 May 2026, 09:45 | 5.13 | 5.13 mg/l |
| 23 Apr 2026, 12:08 | 6.73 | 6.73 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.29 mg/l
Sampled 3 Aug 2026, 59 days ago · 5 results banked
Every result (5)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Aug 2026, 12:12 | 0.29 | 0.29 mg/l |
| 2 Jul 2026, 10:52 | 0.25 | 0.25 mg/l |
| 4 Jun 2026, 12:15 | 0.19 | 0.19 mg/l |
| 21 May 2026, 09:45 | 0.19 | 0.19 mg/l |
| 23 Apr 2026, 12:08 | 0.099 | 0.099 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
1100 µS/cm
Sampled 3 Aug 2026, 59 days ago · 5 results banked
Every result (5)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Aug 2026, 12:12 | 1100 | 1100 µS/cm |
| 2 Jul 2026, 10:52 | 959 | 959 µS/cm |
| 4 Jun 2026, 12:15 | 868 | 868 µS/cm |
| 21 May 2026, 09:45 | 907 | 907 µS/cm |
| 23 Apr 2026, 12:08 | 879 | 879 µS/cm |
Everything measured here
14 determinands, each kept by its code, unit and sample material: results in different units or on different materials are never mixed. A “below” result is under the laboratory's detection limit, not zero.
Show all 14 rows
| Determinand | Material | Results | First – last | Latest result |
|---|---|---|---|---|
| Oxygen, Dissolved, % Saturation 9901 | River water | 5 | Apr 2026 – Aug 2026 | 97.3% 3 Aug 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 5 | Apr 2026 – Aug 2026 | 8.49 mg/l 3 Aug 2026 |
| Temperature of Water 0076 | River water | 5 | Apr 2026 – Aug 2026 | 22 °C 3 Aug 2026 |
| pH 0061 | River water | 5 | Apr 2026 – Aug 2026 | 7.76 3 Aug 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 5 | Apr 2026 – Aug 2026 | 0.2 mg/l 3 Aug 2026 |
| Nitrate as N 0117 | River water | 5 | Apr 2026 – Aug 2026 | 7.57 mg/l 3 Aug 2026 |
| Orthophosphate, reactive as P 0180 | River water | 5 | Apr 2026 – Aug 2026 | 0.29 mg/l 3 Aug 2026 |
| Conductivity at 25 C 0077 | River water | 5 | Apr 2026 – Aug 2026 | 1100 µS/cm 3 Aug 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 5 | Apr 2026 – Aug 2026 | 200 mg/l 3 Aug 2026 |
| Ammonia un-ionised as N 0119 | River water | 5 | Apr 2026 – Aug 2026 | 0.0051 mg/l 3 Aug 2026 |
| Cyanide : Free as CN 0174 | River water | 30 | Oct 2023 – Aug 2026 | below 0.005 mg/l 3 Aug 2026 |
| Cyanide as CN 0175 | River water | 30 | Oct 2023 – Aug 2026 | below 0.005 mg/l 3 Aug 2026 |
| Nitrite as N 0118 | River water | 5 | Apr 2026 – Aug 2026 | 0.13 mg/l 3 Aug 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 5 | Apr 2026 – Aug 2026 | 7.7 mg/l 3 Aug 2026 |
FloodRadar does not grade these results: there is no overall score, and official river classifications are a separate dataset. A sample taken downstream of an overflow does not by itself show where anything in it came from. River connections and distances are traced on OS Open Rivers (edition 2026-04), which leaves out many small channels.
Water samples: Environment Agency Water Quality Archive, © Environment Agency and/or database right 2026, Open Government Licence v3.0.
Contains OS data © Crown copyright and database rights 2026.