River Monnow at Clodock Mill
EA name: RIVER MONNOW AT CLODOCK MILL (also listed as “RIVER MONNOW AL CLODOCK MILL”)
Environment Agency sampling point MD-H0000004 · 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
- 28 Mar 2025, 10:1819 months ago · time as the Environment Agency records it (UK clock time; the source gives no time zone). Not sampled since, as far as the archive shows: the Environment Agency was asked up to 27 Oct 2026 and had nothing newer.
- Samples banked
- 16 since 4 Oct 2023 Imported periods: 1 Oct 2023 – 27 Oct 2026. Samples outside them are not shown here.
- Latest sample
- River / running surface water Environmental monitoring statutory (EU directives)
- Where
- National Grid 332689, 227434As published, to the nearest 1 m. Open in a map
- River, by its own name
- Monnow
- River, by the map
- Afon MynwyPlaced on the river its name gives, 5 m from the line.
- Next gauge downstream
- Grosmont Rhosllwyn River Station On the Monnow · 19 km along the river
- Why it was sampled
- Environmental monitoring statutory (EU directives) (16 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
106.5%
Sampled 28 Mar 2025, 19 months ago · 16 results banked
Every result (16)
| Sampled | Result as published | Reads as |
|---|---|---|
| 28 Mar 2025, 10:18 | 106.5 | 106.5% |
| 12 Feb 2025, 11:34 | 102.3 | 102.3% |
| 6 Jan 2025, 13:47 | 101.2 | 101.2% |
| 4 Dec 2024, 11:12 | 100.7 | 100.7% |
| 7 Nov 2024, 11:16 | 98 | 98% |
| 8 Oct 2024, 11:03 | 102.4 | 102.4% |
| 6 Sep 2024, 11:37 | 96.7 | 96.7% |
| 9 Aug 2024, 10:59 | 98.6 | 98.6% |
| 3 Jul 2024, 11:42 | 99.8 | 99.8% |
| 5 Jun 2024, 11:14 | 100.4 | 100.4% |
| 7 Mar 2024, 11:00 | 100.8 | 100.8% |
| 8 Feb 2024, 11:34 | 100.8 | 100.8% |
| 26 Jan 2024, 12:31 | 102.1 | 102.1% |
| 8 Dec 2023, 12:49 | 100.8 | 100.8% |
| 9 Nov 2023, 11:20 | 101.4 | 101.4% |
| 4 Oct 2023, 07:36 | 97.8 | 97.8% |
Dissolved oxygen
as O2 · code 9924 · mg/l
12.1 mg/l
Sampled 28 Mar 2025, 19 months ago · 16 results banked
Every result (16)
| Sampled | Result as published | Reads as |
|---|---|---|
| 28 Mar 2025, 10:18 | 12.1 | 12.1 mg/l |
| 12 Feb 2025, 11:34 | 13.1 | 13.1 mg/l |
| 6 Jan 2025, 13:47 | 12.9 | 12.9 mg/l |
| 4 Dec 2024, 11:12 | 12.2 | 12.2 mg/l |
| 7 Nov 2024, 11:16 | 10.8 | 10.8 mg/l |
| 8 Oct 2024, 11:03 | 11 | 11 mg/l |
| 6 Sep 2024, 11:37 | 9.81 | 9.81 mg/l |
| 9 Aug 2024, 10:59 | 9.69 | 9.69 mg/l |
| 3 Jul 2024, 11:42 | 10.4 | 10.4 mg/l |
| 5 Jun 2024, 11:14 | 11.2 | 11.2 mg/l |
| 7 Mar 2024, 11:00 | 12.6 | 12.6 mg/l |
| 8 Feb 2024, 11:34 | 12.5 | 12.5 mg/l |
| 26 Jan 2024, 12:31 | 12.4 | 12.4 mg/l |
| 8 Dec 2023, 12:49 | 12 | 12 mg/l |
| 9 Nov 2023, 11:20 | 11.7 | 11.7 mg/l |
| 4 Oct 2023, 07:36 | 10.5 | 10.5 mg/l |
Water temperature
code 0076 · °C
9.7 °C
Sampled 28 Mar 2025, 19 months ago · 16 results banked
Every result (16)
| Sampled | Result as published | Reads as |
|---|---|---|
| 28 Mar 2025, 10:18 | 9.7 | 9.7 °C |
| 12 Feb 2025, 11:34 | 4.9 | 4.9 °C |
| 6 Jan 2025, 13:47 | 4.9 | 4.9 °C |
| 4 Dec 2024, 11:12 | 7.1 | 7.1 °C |
| 7 Nov 2024, 11:16 | 11 | 11 °C |
| 8 Oct 2024, 11:03 | 11.9 | 11.9 °C |
| 6 Sep 2024, 11:37 | 14.6 | 14.6 °C |
| 9 Aug 2024, 10:59 | 16.1 | 16.1 °C |
| 3 Jul 2024, 11:42 | 13.4 | 13.4 °C |
| 5 Jun 2024, 11:14 | 10.3 | 10.3 °C |
| 7 Mar 2024, 11:00 | 5.7 | 5.7 °C |
| 8 Feb 2024, 11:34 | 6 | 6 °C |
| 26 Jan 2024, 12:31 | 7 | 7 °C |
| 8 Dec 2023, 12:49 | 7.8 | 7.8 °C |
| 9 Nov 2023, 11:20 | 8.9 | 8.9 °C |
| 4 Oct 2023, 07:36 | 12 | 12 °C |
pH
code 0061
8.27
Sampled 28 Mar 2025, 19 months ago · 16 results banked
Every result (16)
| Sampled | Result as published | Reads as |
|---|---|---|
| 28 Mar 2025, 10:18 | 8.27 | 8.27 |
| 12 Feb 2025, 11:34 | 8.3 | 8.3 |
| 6 Jan 2025, 13:47 | 7.96 | 7.96 |
| 4 Dec 2024, 11:12 | 8.17 | 8.17 |
| 7 Nov 2024, 11:16 | 8.24 | 8.24 |
| 8 Oct 2024, 11:03 | 8.08 | 8.08 |
| 6 Sep 2024, 11:37 | 8.09 | 8.09 |
| 9 Aug 2024, 10:59 | 8.18 | 8.18 |
| 3 Jul 2024, 11:42 | 8.28 | 8.28 |
| 5 Jun 2024, 11:14 | 8.37 | 8.37 |
| 7 Mar 2024, 11:00 | 8.23 | 8.23 |
| 8 Feb 2024, 11:34 | 7.62 | 7.62 |
| 26 Jan 2024, 12:31 | 7.85 | 7.85 |
| 8 Dec 2023, 12:49 | 7.99 | 7.99 |
| 9 Nov 2023, 11:20 | 8.22 | 8.22 |
| 4 Oct 2023, 07:36 | 8.06 | 8.06 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
below 0.03 mg/l (not detected above this)
Sampled 28 Mar 2025, 19 months ago · 15 results banked
Every result (15)
| Sampled | Result as published | Reads as |
|---|---|---|
| 28 Mar 2025, 10:18 | <0.03 | below 0.03 mg/l (not detected above this) |
| 12 Feb 2025, 11:34 | <0.03 | below 0.03 mg/l (not detected above this) |
| 6 Jan 2025, 13:47 | <0.03 | below 0.03 mg/l (not detected above this) |
| 4 Dec 2024, 11:12 | <0.03 | below 0.03 mg/l (not detected above this) |
| 7 Nov 2024, 11:16 | <0.03 | below 0.03 mg/l (not detected above this) |
| 8 Oct 2024, 11:03 | <0.03 | below 0.03 mg/l (not detected above this) |
| 6 Sep 2024, 11:37 | <0.03 | below 0.03 mg/l (not detected above this) |
| 9 Aug 2024, 10:59 | <0.03 | below 0.03 mg/l (not detected above this) |
| 3 Jul 2024, 11:42 | <0.03 | below 0.03 mg/l (not detected above this) |
| 5 Jun 2024, 11:14 | <0.03 | below 0.03 mg/l (not detected above this) |
| 7 Mar 2024, 11:00 | <0.03 | below 0.03 mg/l (not detected above this) |
| 8 Feb 2024, 11:34 | 0.042 | 0.042 mg/l |
| 26 Jan 2024, 12:31 | <0.03 | below 0.03 mg/l (not detected above this) |
| 8 Dec 2023, 12:49 | <0.03 | below 0.03 mg/l (not detected above this) |
| 9 Nov 2023, 11:20 | <0.03 | below 0.03 mg/l (not detected above this) |
Nitrate
as nitrogen (N) · code 0117 · mg/l
0.366 mg/l
Sampled 28 Mar 2025, 19 months ago · 15 results banked
Every result (15)
| Sampled | Result as published | Reads as |
|---|---|---|
| 28 Mar 2025, 10:18 | 0.366 | 0.366 mg/l |
| 12 Feb 2025, 11:34 | 0.886 | 0.886 mg/l |
| 6 Jan 2025, 13:47 | 0.996 | 0.996 mg/l |
| 4 Dec 2024, 11:12 | 0.716 | 0.716 mg/l |
| 7 Nov 2024, 11:16 | 0.636 | 0.636 mg/l |
| 8 Oct 2024, 11:03 | 0.516 | 0.516 mg/l |
| 6 Sep 2024, 11:37 | 0.646 | 0.646 mg/l |
| 9 Aug 2024, 10:59 | 0.656 | 0.656 mg/l |
| 3 Jul 2024, 11:42 | 0.866 | 0.866 mg/l |
| 5 Jun 2024, 11:14 | 0.806 | 0.806 mg/l |
| 7 Mar 2024, 11:00 | 0.836 | 0.836 mg/l |
| 8 Feb 2024, 11:34 | 0.626 | 0.626 mg/l |
| 26 Jan 2024, 12:31 | 0.816 | 0.816 mg/l |
| 8 Dec 2023, 12:49 | 0.996 | 0.996 mg/l |
| 9 Nov 2023, 11:20 | 0.706 | 0.706 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
1.1 mg/l
Sampled 28 Mar 2025, 19 months ago · 15 results banked
Every result (15)
| Sampled | Result as published | Reads as |
|---|---|---|
| 28 Mar 2025, 10:18 | 1.1 | 1.1 mg/l |
| 12 Feb 2025, 11:34 | 0.018 | 0.018 mg/l |
| 6 Jan 2025, 13:47 | 0.043 | 0.043 mg/l |
| 4 Dec 2024, 11:12 | 0.017 | 0.017 mg/l |
| 7 Nov 2024, 11:16 | 0.012 | 0.012 mg/l |
| 8 Oct 2024, 11:03 | 0.039 | 0.039 mg/l |
| 6 Sep 2024, 11:37 | 0.042 | 0.042 mg/l |
| 9 Aug 2024, 10:59 | 0.043 | 0.043 mg/l |
| 3 Jul 2024, 11:42 | 0.043 | 0.043 mg/l |
| 5 Jun 2024, 11:14 | 0.034 | 0.034 mg/l |
| 7 Mar 2024, 11:00 | 0.016 | 0.016 mg/l |
| 8 Feb 2024, 11:34 | 0.069 | 0.069 mg/l |
| 26 Jan 2024, 12:31 | 0.038 | 0.038 mg/l |
| 8 Dec 2023, 12:49 | 0.03 | 0.03 mg/l |
| 9 Nov 2023, 11:20 | <0.01 | below 0.01 mg/l (not detected above this) |
Conductivity
at 25 °C · code 0077 · µS/cm
353 µS/cm
Sampled 28 Mar 2025, 19 months ago · 16 results banked
Every result (16)
| Sampled | Result as published | Reads as |
|---|---|---|
| 28 Mar 2025, 10:18 | 353 | 353 µS/cm |
| 12 Feb 2025, 11:34 | 267 | 267 µS/cm |
| 6 Jan 2025, 13:47 | 130 | 130 µS/cm |
| 4 Dec 2024, 11:12 | 237 | 237 µS/cm |
| 7 Nov 2024, 11:16 | 330 | 330 µS/cm |
| 8 Oct 2024, 11:03 | 202 | 202 µS/cm |
| 6 Sep 2024, 11:37 | 358 | 358 µS/cm |
| 9 Aug 2024, 10:59 | 383 | 383 µS/cm |
| 3 Jul 2024, 11:42 | 391 | 391 µS/cm |
| 5 Jun 2024, 11:14 | 354 | 354 µS/cm |
| 7 Mar 2024, 11:00 | 239 | 239 µS/cm |
| 8 Feb 2024, 11:34 | 136 | 136 µS/cm |
| 26 Jan 2024, 12:31 | 187 | 187 µS/cm |
| 8 Dec 2023, 12:49 | 189 | 189 µS/cm |
| 9 Nov 2023, 11:20 | 249 | 249 µS/cm |
| 4 Oct 2023, 07:36 | 297 | 297 µS/cm |
Everything measured here
12 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 12 rows
| Determinand | Material | Results | First – last | Latest result |
|---|---|---|---|---|
| Oxygen, Dissolved, % Saturation 9901 | River water | 16 | Oct 2023 – Mar 2025 | 106.5% 28 Mar 2025 |
| Oxygen, Dissolved as O2 9924 | River water | 16 | Oct 2023 – Mar 2025 | 12.1 mg/l 28 Mar 2025 |
| Temperature of Water 0076 | River water | 16 | Oct 2023 – Mar 2025 | 9.7 °C 28 Mar 2025 |
| pH 0061 | River water | 16 | Oct 2023 – Mar 2025 | 8.27 28 Mar 2025 |
| Ammoniacal Nitrogen as N 0111 | River water | 15 | Nov 2023 – Mar 2025 | below 0.03 mg/l 28 Mar 2025 |
| Nitrate as N 0117 | River water | 15 | Nov 2023 – Mar 2025 | 0.366 mg/l 28 Mar 2025 |
| Orthophosphate, reactive as P 0180 | River water | 15 | Nov 2023 – Mar 2025 | 1.1 mg/l 28 Mar 2025 |
| Conductivity at 25 C 0077 | River water | 16 | Oct 2023 – Mar 2025 | 353 µS/cm 28 Mar 2025 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 15 | Nov 2023 – Mar 2025 | 170 mg/l 28 Mar 2025 |
| Ammonia un-ionised as N 0119 | River water | 15 | Nov 2023 – Mar 2025 | below 0.00054 mg/l 28 Mar 2025 |
| Nitrite as N 0118 | River water | 15 | Nov 2023 – Mar 2025 | below 0.004 mg/l 28 Mar 2025 |
| Nitrogen, Total Oxidised as N 0116 | River water | 15 | Nov 2023 – Mar 2025 | 0.37 mg/l 28 Mar 2025 |
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.