Tresillian River at Tresowgar Bridge
EA name: TRESILLIAN RIVER AT TRESOWGAR BRIDGE
Environment Agency sampling point SW-81940185 · 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
- 4 Sep 2026, 13:5534 days ago · time as the Environment Agency records it (UK clock time; the source gives no time zone)
- Samples banked
- 18 since 7 Apr 2025 Imported periods: 1 Oct 2023 – 8 Oct 2026. Samples outside them are not shown here.
- Latest sample
- River / running surface water Planned investigation (local monitoring) · results completed 8 Sep 2026
- Where
- National Grid 188550, 48100As published, to the nearest 10 m. Open in a map
- River, by its own name
- Tresillian
- River, by the map
- Tresillian RiverPlaced on the river its name gives, 16 m from the line.
- Next gauge downstream
- None tracedIts water reaches the sea without passing a gauge.
- Nearest gauge upstream
- Ladock On the Tresillian River · 3.4 km along the river
- Why it was sampled
- Planned investigation (local monitoring) (18 samples)
Results here were completed a median of 4 days after the sample was taken (2 to 5 days, 4 samples).
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
91.1%
Sampled 4 Sep 2026, 34 days ago · 18 results banked
Every result (18)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Sep 2026, 13:55 | 91.1 | 91.1% |
| 11 Aug 2026, 10:18 | 90.2 | 90.2% |
| 14 Jul 2026, 12:59 | 91.6 | 91.6% |
| 16 Jun 2026, 11:19 | 94.6 | 94.6% |
| 13 May 2026, 15:15 | 97.5 | 97.5% |
| 10 Apr 2026, 11:44 | 98 | 98% |
| 6 Mar 2026, 12:09 | 96.9 | 96.9% |
| 4 Feb 2026, 10:28 | 98.3 | 98.3% |
| 5 Jan 2026, 12:05 | 95.5 | 95.5% |
| 9 Dec 2025, 10:37 | 92.8 | 92.8% |
| 14 Nov 2025, 13:49 | 89.8 | 89.8% |
| 21 Oct 2025, 14:25 | 91.2 | 91.2% |
| 3 Sep 2025, 11:13 | 92.2 | 92.2% |
| 7 Aug 2025, 10:18 | 96 | 96% |
| 8 Jul 2025, 09:00 | 95.8 | 95.8% |
| 9 Jun 2025, 11:57 | 95.4 | 95.4% |
| 14 May 2025, 10:43 | 98.4 | 98.4% |
| 7 Apr 2025, 11:22 | 99.7 | 99.7% |
Dissolved oxygen
as O2 · code 9924 · mg/l
8.71 mg/l
Sampled 4 Sep 2026, 34 days ago · 18 results banked
Every result (18)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Sep 2026, 13:55 | 8.71 | 8.71 mg/l |
| 11 Aug 2026, 10:18 | 8.88 | 8.88 mg/l |
| 14 Jul 2026, 12:59 | 8.49 | 8.49 mg/l |
| 16 Jun 2026, 11:19 | 9.68 | 9.68 mg/l |
| 13 May 2026, 15:15 | 10.5 | 10.5 mg/l |
| 10 Apr 2026, 11:44 | 11.1 | 11.1 mg/l |
| 6 Mar 2026, 12:09 | 11 | 11 mg/l |
| 4 Feb 2026, 10:28 | 11.2 | 11.2 mg/l |
| 5 Jan 2026, 12:05 | 11.7 | 11.7 mg/l |
| 9 Dec 2025, 10:37 | 9.93 | 9.93 mg/l |
| 14 Nov 2025, 13:49 | 9.33 | 9.33 mg/l |
| 21 Oct 2025, 14:25 | 9.59 | 9.59 mg/l |
| 3 Sep 2025, 11:13 | 9.19 | 9.19 mg/l |
| 7 Aug 2025, 10:18 | 9.61 | 9.61 mg/l |
| 8 Jul 2025, 09:00 | 9.74 | 9.74 mg/l |
| 9 Jun 2025, 11:57 | 9.94 | 9.94 mg/l |
| 14 May 2025, 10:43 | 10.5 | 10.5 mg/l |
| 7 Apr 2025, 11:22 | 11.5 | 11.5 mg/l |
Water temperature
code 0076 · °C
17.4 °C
Sampled 4 Sep 2026, 34 days ago · 18 results banked
Every result (18)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Sep 2026, 13:55 | 17.4 | 17.4 °C |
| 11 Aug 2026, 10:18 | 16 | 16 °C |
| 14 Jul 2026, 12:59 | 18.9 | 18.9 °C |
| 16 Jun 2026, 11:19 | 14.2 | 14.2 °C |
| 13 May 2026, 15:15 | 12 | 12 °C |
| 10 Apr 2026, 11:44 | 9.6 | 9.6 °C |
| 6 Mar 2026, 12:09 | 9.7 | 9.7 °C |
| 4 Feb 2026, 10:28 | 9.6 | 9.6 °C |
| 5 Jan 2026, 12:05 | 6.7 | 6.7 °C |
| 9 Dec 2025, 10:37 | 12.2 | 12.2 °C |
| 14 Nov 2025, 13:49 | 13.5 | 13.5 °C |
| 21 Oct 2025, 14:25 | 13 | 13 °C |
| 3 Sep 2025, 11:13 | 15.4 | 15.4 °C |
| 7 Aug 2025, 10:18 | 15.2 | 15.2 °C |
| 8 Jul 2025, 09:00 | 14.5 | 14.5 °C |
| 9 Jun 2025, 11:57 | 13.4 | 13.4 °C |
| 14 May 2025, 10:43 | 12.2 | 12.2 °C |
| 7 Apr 2025, 11:22 | 9 | 9 °C |
pH
code 0061
7.43
Sampled 4 Sep 2026, 34 days ago · 18 results banked
Every result (18)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Sep 2026, 13:55 | 7.43 | 7.43 |
| 11 Aug 2026, 10:18 | 7.38 | 7.38 |
| 14 Jul 2026, 12:59 | 7.35 | 7.35 |
| 16 Jun 2026, 11:19 | 7.57 | 7.57 |
| 13 May 2026, 15:15 | 7.46 | 7.46 |
| 10 Apr 2026, 11:44 | 7.5 | 7.5 |
| 6 Mar 2026, 12:09 | 7.47 | 7.47 |
| 4 Feb 2026, 10:28 | 7.23 | 7.23 |
| 5 Jan 2026, 12:05 | 7.35 | 7.35 |
| 9 Dec 2025, 10:37 | 7.07 | 7.07 |
| 14 Nov 2025, 13:49 | 7.3 | 7.3 |
| 21 Oct 2025, 14:25 | 7.57 | 7.57 |
| 3 Sep 2025, 11:13 | 7.59 | 7.59 |
| 7 Aug 2025, 10:18 | 7.54 | 7.54 |
| 8 Jul 2025, 09:00 | 7.66 | 7.66 |
| 9 Jun 2025, 11:57 | 7.52 | 7.52 |
| 14 May 2025, 10:43 | 7.59 | 7.59 |
| 7 Apr 2025, 11:22 | 7.73 | 7.73 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
below 0.03 mg/l (not detected above this)
Sampled 11 Aug 2026, 58 days ago · 17 results banked
Every result (17)
| Sampled | Result as published | Reads as |
|---|---|---|
| 11 Aug 2026, 10:18 | <0.03 | below 0.03 mg/l (not detected above this) |
| 14 Jul 2026, 12:59 | <0.03 | below 0.03 mg/l (not detected above this) |
| 16 Jun 2026, 11:19 | 0.035 | 0.035 mg/l |
| 13 May 2026, 15:15 | 0.085 | 0.085 mg/l |
| 10 Apr 2026, 11:44 | <0.03 | below 0.03 mg/l (not detected above this) |
| 6 Mar 2026, 12:09 | <0.03 | below 0.03 mg/l (not detected above this) |
| 4 Feb 2026, 10:28 | 0.032 | 0.032 mg/l |
| 5 Jan 2026, 12:05 | 0.088 | 0.088 mg/l |
| 9 Dec 2025, 10:37 | <0.03 | below 0.03 mg/l (not detected above this) |
| 14 Nov 2025, 13:49 | <0.03 | below 0.03 mg/l (not detected above this) |
| 21 Oct 2025, 14:25 | <0.03 | below 0.03 mg/l (not detected above this) |
| 3 Sep 2025, 11:13 | 0.033 | 0.033 mg/l |
| 7 Aug 2025, 10:18 | <0.03 | below 0.03 mg/l (not detected above this) |
| 8 Jul 2025, 09:00 | <0.03 | below 0.03 mg/l (not detected above this) |
| 9 Jun 2025, 11:57 | 0.17 | 0.17 mg/l |
| 14 May 2025, 10:43 | <0.03 | below 0.03 mg/l (not detected above this) |
| 7 Apr 2025, 11:22 | <0.03 | below 0.03 mg/l (not detected above this) |
Nitrate
as nitrogen (N) · code 0117 · mg/l
3.4 mg/l
Sampled 11 Aug 2026, 58 days ago · 17 results banked
Every result (17)
| Sampled | Result as published | Reads as |
|---|---|---|
| 11 Aug 2026, 10:18 | 3.4 | 3.4 mg/l |
| 14 Jul 2026, 12:59 | 3.69 | 3.69 mg/l |
| 16 Jun 2026, 11:19 | 4.07 | 4.07 mg/l |
| 13 May 2026, 15:15 | 4.58 | 4.58 mg/l |
| 10 Apr 2026, 11:44 | 4.89 | 4.89 mg/l |
| 6 Mar 2026, 12:09 | 5.4 | 5.4 mg/l |
| 4 Feb 2026, 10:28 | 5.29 | 5.29 mg/l |
| 5 Jan 2026, 12:05 | 4.38 | 4.38 mg/l |
| 9 Dec 2025, 10:37 | 3.3 | 3.3 mg/l |
| 14 Nov 2025, 13:49 | 3.67 | 3.67 mg/l |
| 21 Oct 2025, 14:25 | 2.2 | 2.2 mg/l |
| 3 Sep 2025, 11:13 | 1.99 | 1.99 mg/l |
| 7 Aug 2025, 10:18 | 3.89 | 3.89 mg/l |
| 8 Jul 2025, 09:00 | 4.49 | 4.49 mg/l |
| 9 Jun 2025, 11:57 | 4.28 | 4.28 mg/l |
| 14 May 2025, 10:43 | 5.09 | 5.09 mg/l |
| 7 Apr 2025, 11:22 | 4.89 | 4.89 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.028 mg/l
Sampled 11 Aug 2026, 58 days ago · 17 results banked
Every result (17)
| Sampled | Result as published | Reads as |
|---|---|---|
| 11 Aug 2026, 10:18 | 0.028 | 0.028 mg/l |
| 14 Jul 2026, 12:59 | 0.035 | 0.035 mg/l |
| 16 Jun 2026, 11:19 | 0.034 | 0.034 mg/l |
| 13 May 2026, 15:15 | <0.01 | below 0.01 mg/l (not detected above this) |
| 10 Apr 2026, 11:44 | 0.013 | 0.013 mg/l |
| 6 Mar 2026, 12:09 | 0.016 | 0.016 mg/l |
| 4 Feb 2026, 10:28 | 0.02 | 0.02 mg/l |
| 5 Jan 2026, 12:05 | 0.03 | 0.03 mg/l |
| 9 Dec 2025, 10:37 | 0.039 | 0.039 mg/l |
| 14 Nov 2025, 13:49 | 0.046 | 0.046 mg/l |
| 21 Oct 2025, 14:25 | 0.036 | 0.036 mg/l |
| 3 Sep 2025, 11:13 | 0.11 | 0.11 mg/l |
| 7 Aug 2025, 10:18 | 0.045 | 0.045 mg/l |
| 8 Jul 2025, 09:00 | 0.03 | 0.03 mg/l |
| 9 Jun 2025, 11:57 | 0.047 | 0.047 mg/l |
| 14 May 2025, 10:43 | 0.015 | 0.015 mg/l |
| 7 Apr 2025, 11:22 | 0.01 | 0.01 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
263 µS/cm
Sampled 4 Sep 2026, 34 days ago · 18 results banked
Every result (18)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Sep 2026, 13:55 | 263 | 263 µS/cm |
| 11 Aug 2026, 10:18 | 245 | 245 µS/cm |
| 14 Jul 2026, 12:59 | 252 | 252 µS/cm |
| 16 Jun 2026, 11:19 | 253 | 253 µS/cm |
| 13 May 2026, 15:15 | 251 | 251 µS/cm |
| 10 Apr 2026, 11:44 | 246 | 246 µS/cm |
| 6 Mar 2026, 12:09 | 243 | 243 µS/cm |
| 4 Feb 2026, 10:28 | 249 | 249 µS/cm |
| 5 Jan 2026, 12:05 | 459 | 459 µS/cm |
| 9 Dec 2025, 10:37 | 210 | 210 µS/cm |
| 14 Nov 2025, 13:49 | 255 | 255 µS/cm |
| 21 Oct 2025, 14:25 | 271 | 271 µS/cm |
| 3 Sep 2025, 11:13 | 297 | 297 µS/cm |
| 7 Aug 2025, 10:18 | 258 | 258 µS/cm |
| 8 Jul 2025, 09:00 | 259 | 259 µS/cm |
| 9 Jun 2025, 11:57 | 251 | 251 µS/cm |
| 14 May 2025, 10:43 | 256 | 256 µS/cm |
| 7 Apr 2025, 11:22 | 252 | 252 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 | 18 | Apr 2025 – Sep 2026 | 91.1% 4 Sep 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 18 | Apr 2025 – Sep 2026 | 8.71 mg/l 4 Sep 2026 |
| Temperature of Water 0076 | River water | 18 | Apr 2025 – Sep 2026 | 17.4 °C 4 Sep 2026 |
| pH 0061 | River water | 18 | Apr 2025 – Sep 2026 | 7.43 4 Sep 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 17 | Apr 2025 – Aug 2026 | below 0.03 mg/l 11 Aug 2026 |
| Nitrate as N 0117 | River water | 17 | Apr 2025 – Aug 2026 | 3.4 mg/l 11 Aug 2026 |
| Orthophosphate, reactive as P 0180 | River water | 17 | Apr 2025 – Aug 2026 | 0.028 mg/l 11 Aug 2026 |
| Conductivity at 25 C 0077 | River water | 18 | Apr 2025 – Sep 2026 | 263 µS/cm 4 Sep 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 17 | Apr 2025 – Aug 2026 | 42 mg/l 11 Aug 2026 |
| Ammonia un-ionised as N 0119 | River water | 17 | Apr 2025 – Aug 2026 | below 0.00021 mg/l 11 Aug 2026 |
| Nitrite as N 0118 | River water | 17 | Apr 2025 – Aug 2026 | 0.0047 mg/l 11 Aug 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 17 | Apr 2025 – Aug 2026 | 3.4 mg/l 11 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.