River Menalhyl at Mawgan Porth Bridge
EA name: RIVER MENALHYL AT MAWGAN PORTH BRIDGE
Environment Agency sampling point SW-82511104 · 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
- 13 Aug 2026, 10:0549 days ago · time as the Environment Agency records it (UK clock time; the source gives no time zone)
- Samples banked
- 27 since 25 Jun 2024 Imported periods: 1 Oct 2023 – 30 Sep 2026. Samples outside them are not shown here.
- Latest sample
- River / running surface water Environmental monitoring statutory (EU directives)
- Where
- National Grid 184949, 67160As published, to the nearest 1 m. Open in a map
- River, by its own name
- Menalhyl
- River, by the map
- River MenalhylPlaced on the river its name gives, 10 m from the line.
- Next gauge downstream
- None tracedIts water reaches the sea without passing a gauge.
- Why it was sampled
- Monitoring (national agency policy) (22 samples)
Environmental monitoring statutory (EU directives) (5 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
95.9%
Sampled 13 Aug 2026, 49 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 13 Aug 2026, 10:05 | 95.9 | 95.9% |
| 10 Jul 2026, 13:44 | 103.4 | 103.4% |
| 8 Jun 2026, 10:12 | 97.2 | 97.2% |
| 12 May 2026, 09:36 | 105.9 | 105.9% |
| 20 Apr 2026, 10:52 | 104.5 | 104.5% |
| 17 Mar 2026, 09:32 | 94.2 | 94.2% |
| 3 Feb 2026, 09:58 | 97 | 97% |
| 2 Jan 2026, 10:08 | 94.6 | 94.6% |
| 11 Dec 2025, 09:27 | 94.1 | 94.1% |
| 10 Nov 2025, 08:36 | 93 | 93% |
| 7 Oct 2025, 09:53 | 95.2 | 95.2% |
| 3 Sep 2025, 12:14 | 89.2 | 89.2% |
| 12 Aug 2025, 09:04 | 91.3 | 91.3% |
| 22 Jul 2025, 10:32 | 90.7 | 90.7% |
| 26 Jun 2025, 14:05 | 103.3 | 103.3% |
| 29 May 2025, 10:04 | 97.7 | 97.7% |
| 11 Apr 2025, 08:08 | 95.3 | 95.3% |
| 28 Mar 2025, 09:37 | 96 | 96% |
| 5 Feb 2025, 09:15 | 96.8 | 96.8% |
| 21 Jan 2025, 10:27 | 98 | 98% |
| 4 Dec 2024, 09:26 | 97.6 | 97.6% |
| 19 Nov 2024, 10:30 | 94.4 | 94.4% |
| 21 Oct 2024, 12:53 | 94 | 94% |
| 30 Sep 2024, 10:25 | 97.9 | 97.9% |
| 23 Aug 2024, 08:36 | 92 | 92% |
| 17 Jul 2024, 10:42 | 96.4 | 96.4% |
| 25 Jun 2024, 12:28 | 100 | 100% |
Dissolved oxygen
as O2 · code 9924 · mg/l
9.09 mg/l
Sampled 13 Aug 2026, 49 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 13 Aug 2026, 10:05 | 9.09 | 9.09 mg/l |
| 10 Jul 2026, 13:44 | 9.14 | 9.14 mg/l |
| 8 Jun 2026, 10:12 | 10.1 | 10.1 mg/l |
| 12 May 2026, 09:36 | 11.5 | 11.5 mg/l |
| 20 Apr 2026, 10:52 | 11.7 | 11.7 mg/l |
| 17 Mar 2026, 09:32 | 10.7 | 10.7 mg/l |
| 3 Feb 2026, 09:58 | 11 | 11 mg/l |
| 2 Jan 2026, 10:08 | 11.3 | 11.3 mg/l |
| 11 Dec 2025, 09:27 | 10.4 | 10.4 mg/l |
| 10 Nov 2025, 08:36 | 10.1 | 10.1 mg/l |
| 7 Oct 2025, 09:53 | 9.94 | 9.94 mg/l |
| 3 Sep 2025, 12:14 | 8.69 | 8.69 mg/l |
| 12 Aug 2025, 09:04 | 8.93 | 8.93 mg/l |
| 22 Jul 2025, 10:32 | 8.95 | 8.95 mg/l |
| 26 Jun 2025, 14:05 | 9.67 | 9.67 mg/l |
| 29 May 2025, 10:04 | 9.78 | 9.78 mg/l |
| 11 Apr 2025, 08:08 | 11.3 | 11.3 mg/l |
| 28 Mar 2025, 09:37 | 10.7 | 10.7 mg/l |
| 5 Feb 2025, 09:15 | 11.5 | 11.5 mg/l |
| 21 Jan 2025, 10:27 | 11.9 | 11.9 mg/l |
| 4 Dec 2024, 09:26 | 11.2 | 11.2 mg/l |
| 19 Nov 2024, 10:30 | 10.3 | 10.3 mg/l |
| 21 Oct 2024, 12:53 | 9.93 | 9.93 mg/l |
| 30 Sep 2024, 10:25 | 10.2 | 10.2 mg/l |
| 23 Aug 2024, 08:36 | 9.13 | 9.13 mg/l |
| 17 Jul 2024, 10:42 | 9.61 | 9.61 mg/l |
| 25 Jun 2024, 12:28 | 9.87 | 9.87 mg/l |
Water temperature
code 0076 · °C
17.8 °C
Sampled 13 Aug 2026, 49 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 13 Aug 2026, 10:05 | 17.8 | 17.8 °C |
| 10 Jul 2026, 13:44 | 21.3 | 21.3 °C |
| 8 Jun 2026, 10:12 | 13.6 | 13.6 °C |
| 12 May 2026, 09:36 | 11.4 | 11.4 °C |
| 20 Apr 2026, 10:52 | 10.2 | 10.2 °C |
| 17 Mar 2026, 09:32 | 9.6 | 9.6 °C |
| 3 Feb 2026, 09:58 | 9.9 | 9.9 °C |
| 2 Jan 2026, 10:08 | 7.7 | 7.7 °C |
| 11 Dec 2025, 09:27 | 10.9 | 10.9 °C |
| 10 Nov 2025, 08:36 | 11.5 | 11.5 °C |
| 7 Oct 2025, 09:53 | 13.3 | 13.3 °C |
| 3 Sep 2025, 12:14 | 16.5 | 16.5 °C |
| 12 Aug 2025, 09:04 | 16.3 | 16.3 °C |
| 22 Jul 2025, 10:32 | 15.9 | 15.9 °C |
| 26 Jun 2025, 14:05 | 18.4 | 18.4 °C |
| 29 May 2025, 10:04 | 15.2 | 15.2 °C |
| 11 Apr 2025, 08:08 | 7.9 | 7.9 °C |
| 28 Mar 2025, 09:37 | 10.5 | 10.5 °C |
| 5 Feb 2025, 09:15 | 7.7 | 7.7 °C |
| 21 Jan 2025, 10:27 | 6.8 | 6.8 °C |
| 4 Dec 2024, 09:26 | 9.2 | 9.2 °C |
| 19 Nov 2024, 10:30 | 11.2 | 11.2 °C |
| 21 Oct 2024, 12:53 | 12.8 | 12.8 °C |
| 30 Sep 2024, 10:25 | 13.3 | 13.3 °C |
| 23 Aug 2024, 08:36 | 15.6 | 15.6 °C |
| 17 Jul 2024, 10:42 | 15.4 | 15.4 °C |
| 25 Jun 2024, 12:28 | 15.9 | 15.9 °C |
pH
code 0061
7.61
Sampled 13 Aug 2026, 49 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 13 Aug 2026, 10:05 | 7.61 | 7.61 |
| 10 Jul 2026, 13:44 | 7.63 | 7.63 |
| 8 Jun 2026, 10:12 | 7.58 | 7.58 |
| 12 May 2026, 09:36 | 7.9 | 7.9 |
| 20 Apr 2026, 10:52 | 7.93 | 7.93 |
| 17 Mar 2026, 09:32 | 7.63 | 7.63 |
| 3 Feb 2026, 09:58 | 7.88 | 7.88 |
| 2 Jan 2026, 10:08 | 7.66 | 7.66 |
| 11 Dec 2025, 09:27 | 7.42 | 7.42 |
| 10 Nov 2025, 08:36 | 7.5 | 7.5 |
| 7 Oct 2025, 09:53 | 7.45 | 7.45 |
| 3 Sep 2025, 12:14 | 7.64 | 7.64 |
| 12 Aug 2025, 09:04 | 7.61 | 7.61 |
| 22 Jul 2025, 10:32 | 7.49 | 7.49 |
| 26 Jun 2025, 14:05 | 8.22 | 8.22 |
| 29 May 2025, 10:04 | 7.73 | 7.73 |
| 11 Apr 2025, 08:08 | 7.65 | 7.65 |
| 28 Mar 2025, 09:37 | 7.78 | 7.78 |
| 5 Feb 2025, 09:15 | 7.67 | 7.67 |
| 21 Jan 2025, 10:27 | 7.78 | 7.78 |
| 4 Dec 2024, 09:26 | 7.5 | 7.5 |
| 19 Nov 2024, 10:30 | 7.53 | 7.53 |
| 21 Oct 2024, 12:53 | 7.51 | 7.51 |
| 30 Sep 2024, 10:25 | 7.45 | 7.45 |
| 23 Aug 2024, 08:36 | 7.88 | 7.88 |
| 17 Jul 2024, 10:42 | 7.52 | 7.52 |
| 25 Jun 2024, 12:28 | 8.2 | 8.2 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
0.032 mg/l
Sampled 13 Aug 2026, 49 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 13 Aug 2026, 10:05 | 0.032 | 0.032 mg/l |
| 10 Jul 2026, 13:44 | <0.03 | below 0.03 mg/l (not detected above this) |
| 8 Jun 2026, 10:12 | <0.03 | below 0.03 mg/l (not detected above this) |
| 12 May 2026, 09:36 | <0.03 | below 0.03 mg/l (not detected above this) |
| 20 Apr 2026, 10:52 | <0.03 | below 0.03 mg/l (not detected above this) |
| 17 Mar 2026, 09:32 | <0.03 | below 0.03 mg/l (not detected above this) |
| 3 Feb 2026, 09:58 | 0.049 | 0.049 mg/l |
| 2 Jan 2026, 10:08 | <0.03 | below 0.03 mg/l (not detected above this) |
| 11 Dec 2025, 09:27 | <0.03 | below 0.03 mg/l (not detected above this) |
| 10 Nov 2025, 08:36 | <0.03 | below 0.03 mg/l (not detected above this) |
| 7 Oct 2025, 09:53 | 0.03 | 0.03 mg/l |
| 3 Sep 2025, 12:14 | <0.03 | below 0.03 mg/l (not detected above this) |
| 12 Aug 2025, 09:04 | <0.03 | below 0.03 mg/l (not detected above this) |
| 22 Jul 2025, 10:32 | <0.03 | below 0.03 mg/l (not detected above this) |
| 26 Jun 2025, 14:05 | <0.03 | below 0.03 mg/l (not detected above this) |
| 29 May 2025, 10:04 | 0.048 | 0.048 mg/l |
| 11 Apr 2025, 08:08 | <0.03 | below 0.03 mg/l (not detected above this) |
| 28 Mar 2025, 09:37 | 0.47 | 0.47 mg/l |
| 5 Feb 2025, 09:15 | <0.03 | below 0.03 mg/l (not detected above this) |
| 21 Jan 2025, 10:27 | 0.11 | 0.11 mg/l |
| 4 Dec 2024, 09:26 | <0.03 | below 0.03 mg/l (not detected above this) |
| 19 Nov 2024, 10:30 | 0.045 | 0.045 mg/l |
| 21 Oct 2024, 12:53 | <0.03 | below 0.03 mg/l (not detected above this) |
| 30 Sep 2024, 10:25 | <0.03 | below 0.03 mg/l (not detected above this) |
| 23 Aug 2024, 08:36 | <0.03 | below 0.03 mg/l (not detected above this) |
| 17 Jul 2024, 10:42 | <0.03 | below 0.03 mg/l (not detected above this) |
| 25 Jun 2024, 12:28 | <0.03 | below 0.03 mg/l (not detected above this) |
Nitrate
as nitrogen (N) · code 0117 · mg/l
13 mg/l
Sampled 13 Aug 2026, 49 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 13 Aug 2026, 10:05 | 13 | 13 mg/l |
| 10 Jul 2026, 13:44 | 11 | 11 mg/l |
| 8 Jun 2026, 10:12 | 4.78 | 4.78 mg/l |
| 12 May 2026, 09:36 | 7.39 | 7.39 mg/l |
| 20 Apr 2026, 10:52 | 5.29 | 5.29 mg/l |
| 17 Mar 2026, 09:32 | 5.29 | 5.29 mg/l |
| 3 Feb 2026, 09:58 | 5.09 | 5.09 mg/l |
| 2 Jan 2026, 10:08 | 5.69 | 5.69 mg/l |
| 11 Dec 2025, 09:27 | 5.39 | 5.39 mg/l |
| 10 Nov 2025, 08:36 | 3.99 | 3.99 mg/l |
| 7 Oct 2025, 09:53 | 5.59 | 5.59 mg/l |
| 3 Sep 2025, 12:14 | 5.09 | 5.09 mg/l |
| 12 Aug 2025, 09:04 | 11 | 11 mg/l |
| 22 Jul 2025, 10:32 | 7.29 | 7.29 mg/l |
| 26 Jun 2025, 14:05 | 6.19 | 6.19 mg/l |
| 29 May 2025, 10:04 | 6.35 | 6.35 mg/l |
| 11 Apr 2025, 08:08 | 7.99 | 7.99 mg/l |
| 28 Mar 2025, 09:37 | 5.97 | 5.97 mg/l |
| 5 Feb 2025, 09:15 | 5.49 | 5.49 mg/l |
| 21 Jan 2025, 10:27 | 5.07 | 5.07 mg/l |
| 4 Dec 2024, 09:26 | 4.89 | 4.89 mg/l |
| 19 Nov 2024, 10:30 | 3.39 | 3.39 mg/l |
| 21 Oct 2024, 12:53 | 4.49 | 4.49 mg/l |
| 30 Sep 2024, 10:25 | 2.09 | 2.09 mg/l |
| 23 Aug 2024, 08:36 | 9.98 | 9.98 mg/l |
| 17 Jul 2024, 10:42 | 5.99 | 5.99 mg/l |
| 25 Jun 2024, 12:28 | 6.89 | 6.89 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.085 mg/l
Sampled 10 Jul 2026, 3 months ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 10 Jul 2026, 13:44 | 0.085 | 0.085 mg/l |
| 8 Jun 2026, 10:12 | 0.05 | 0.05 mg/l |
| 12 May 2026, 09:36 | 0.059 | 0.059 mg/l |
| 20 Apr 2026, 10:52 | 0.027 | 0.027 mg/l |
| 17 Mar 2026, 09:32 | 0.028 | 0.028 mg/l |
| 3 Feb 2026, 09:58 | 0.034 | 0.034 mg/l |
| 2 Jan 2026, 10:08 | 0.054 | 0.054 mg/l |
| 11 Dec 2025, 09:27 | 0.032 | 0.032 mg/l |
| 10 Nov 2025, 08:36 | 0.03 | 0.03 mg/l |
| 7 Oct 2025, 09:53 | 0.053 | 0.053 mg/l |
| 3 Sep 2025, 12:14 | 0.084 | 0.084 mg/l |
| 12 Aug 2025, 09:04 | 0.085 | 0.085 mg/l |
| 22 Jul 2025, 10:32 | 0.061 | 0.061 mg/l |
| 26 Jun 2025, 14:05 | 0.054 | 0.054 mg/l |
| 29 May 2025, 10:04 | 0.049 | 0.049 mg/l |
| 11 Apr 2025, 08:08 | 0.042 | 0.042 mg/l |
| 28 Mar 2025, 09:37 | 0.082 | 0.082 mg/l |
| 5 Feb 2025, 09:15 | 0.029 | 0.029 mg/l |
| 21 Jan 2025, 10:27 | 0.037 | 0.037 mg/l |
| 4 Dec 2024, 09:26 | 0.025 | 0.025 mg/l |
| 19 Nov 2024, 10:30 | 0.043 | 0.043 mg/l |
| 21 Oct 2024, 12:53 | 0.024 | 0.024 mg/l |
| 30 Sep 2024, 10:25 | 0.058 | 0.058 mg/l |
| 23 Aug 2024, 08:36 | 0.11 | 0.11 mg/l |
| 17 Jul 2024, 10:42 | 0.042 | 0.042 mg/l |
| 25 Jun 2024, 12:28 | 0.053 | 0.053 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
448 µS/cm
Sampled 13 Aug 2026, 49 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 13 Aug 2026, 10:05 | 448 | 448 µS/cm |
| 10 Jul 2026, 13:44 | 393 | 393 µS/cm |
| 8 Jun 2026, 10:12 | 283 | 283 µS/cm |
| 12 May 2026, 09:36 | 325 | 325 µS/cm |
| 20 Apr 2026, 10:52 | 307 | 307 µS/cm |
| 17 Mar 2026, 09:32 | 280 | 280 µS/cm |
| 3 Feb 2026, 09:58 | 341 | 341 µS/cm |
| 2 Jan 2026, 10:08 | 285 | 285 µS/cm |
| 11 Dec 2025, 09:27 | 278 | 278 µS/cm |
| 10 Nov 2025, 08:36 | 316 | 316 µS/cm |
| 7 Oct 2025, 09:53 | 341 | 341 µS/cm |
| 3 Sep 2025, 12:14 | 316 | 316 µS/cm |
| 12 Aug 2025, 09:04 | 402 | 402 µS/cm |
| 22 Jul 2025, 10:32 | 351 | 351 µS/cm |
| 26 Jun 2025, 14:05 | 331 | 331 µS/cm |
| 29 May 2025, 10:04 | 316 | 316 µS/cm |
| 11 Apr 2025, 08:08 | 342 | 342 µS/cm |
| 28 Mar 2025, 09:37 | 309 | 309 µS/cm |
| 5 Feb 2025, 09:15 | 282 | 282 µS/cm |
| 21 Jan 2025, 10:27 | 281 | 281 µS/cm |
| 4 Dec 2024, 09:26 | 278 | 278 µS/cm |
| 19 Nov 2024, 10:30 | 257 | 257 µS/cm |
| 21 Oct 2024, 12:53 | 277 | 277 µS/cm |
| 30 Sep 2024, 10:25 | 239 | 239 µS/cm |
| 23 Aug 2024, 08:36 | 432 | 432 µS/cm |
| 17 Jul 2024, 10:42 | 329 | 329 µS/cm |
| 25 Jun 2024, 12:28 | 332 | 332 µS/cm |
Everything measured here
13 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 13 rows
| Determinand | Material | Results | First – last | Latest result |
|---|---|---|---|---|
| Oxygen, Dissolved, % Saturation 9901 | River water | 27 | Jun 2024 – Aug 2026 | 95.9% 13 Aug 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 27 | Jun 2024 – Aug 2026 | 9.09 mg/l 13 Aug 2026 |
| Temperature of Water 0076 | River water | 27 | Jun 2024 – Aug 2026 | 17.8 °C 13 Aug 2026 |
| pH 0061 | River water | 27 | Jun 2024 – Aug 2026 | 7.61 13 Aug 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 27 | Jun 2024 – Aug 2026 | 0.032 mg/l 13 Aug 2026 |
| Nitrate as N 0117 | River water | 27 | Jun 2024 – Aug 2026 | 13 mg/l 13 Aug 2026 |
| Orthophosphate, reactive as P 0180 | River water | 26 | Jun 2024 – Jul 2026 | 0.085 mg/l 10 Jul 2026 |
| Conductivity at 25 C 0077 | River water | 27 | Jun 2024 – Aug 2026 | 448 µS/cm 13 Aug 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 27 | Jun 2024 – Aug 2026 | 63 mg/l 13 Aug 2026 |
| Ammonia un-ionised as N 0119 | River water | 27 | Jun 2024 – Aug 2026 | 0.00043 mg/l 13 Aug 2026 |
| BOD : 5 Day ATU 0085 | River water | 22 | Jun 2024 – May 2026 | below 3 mg/l 12 May 2026 |
| Nitrite as N 0118 | River water | 27 | Jun 2024 – Aug 2026 | 0.016 mg/l 13 Aug 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 27 | Jun 2024 – Aug 2026 | 13 mg/l 13 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.