River Tamar upstream of Gunnislake Weir
EA name: RIVER TAMAR U/S GUNNISLAKE WEIR
Environment Agency sampling point SW-81250142 · 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
- 24 Mar 2026, 12:486 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 30 Sep 2026 and had nothing newer.
- Samples banked
- 20 since 19 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 243683, 71149As published, to the nearest 1 m. Open in a map
- River, by its own name
- Tamar
- River, by the map
- River TamarPlaced on the river its name gives, 17 m from the line.
- Next gauge downstream
- None tracedIts water reaches the sea without passing a gauge.
- Nearest gauge upstream
- Gunnislake On the River Tamar · 3.1 km along the river
- Why it was sampled
- Monitoring (national agency policy) (12 samples)
Planned investigation (local monitoring) (8 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
90.4%
Sampled 24 Mar 2026, 6 months ago · 20 results banked
Every result (20)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 90.4 | 90.4% |
| 6 Feb 2026, 14:18 | 99 | 99% |
| 19 Jan 2026, 12:59 | 99.9 | 99.9% |
| 9 Dec 2025, 11:36 | 93.6 | 93.6% |
| 6 Nov 2025, 11:34 | 98.5 | 98.5% |
| 2 Oct 2025, 10:54 | 94.8 | 94.8% |
| 4 Sep 2025, 11:52 | 94.5 | 94.5% |
| 12 Aug 2025, 10:35 | 91.2 | 91.2% |
| 23 Jul 2025, 10:58 | 90 | 90% |
| 9 Jun 2025, 11:04 | 90 | 90% |
| 12 May 2025, 12:15 | 95.9 | 95.9% |
| 11 Apr 2025, 14:00 | 99.5 | 99.5% |
| 6 Mar 2024, 13:52 | 99.9 | 99.9% |
| 16 Feb 2024, 11:06 | 96.7 | 96.7% |
| 23 Jan 2024, 13:43 | 92.3 | 92.3% |
| 16 Jan 2024, 12:47 | 99.5 | 99.5% |
| 13 Dec 2023, 10:17 | 97.3 | 97.3% |
| 1 Dec 2023, 11:47 | 98.8 | 98.8% |
| 15 Nov 2023, 12:27 | 97.6 | 97.6% |
| 19 Oct 2023, 12:38 | 101.5 | 101.5% |
Dissolved oxygen
as O2 · code 9924 · mg/l
10.1 mg/l
Sampled 24 Mar 2026, 6 months ago · 20 results banked
Every result (20)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 10.1 | 10.1 mg/l |
| 6 Feb 2026, 14:18 | 11.3 | 11.3 mg/l |
| 19 Jan 2026, 12:59 | 12 | 12 mg/l |
| 9 Dec 2025, 11:36 | 10.1 | 10.1 mg/l |
| 6 Nov 2025, 11:34 | 10.3 | 10.3 mg/l |
| 2 Oct 2025, 10:54 | 10.1 | 10.1 mg/l |
| 4 Sep 2025, 11:52 | 9.24 | 9.24 mg/l |
| 12 Aug 2025, 10:35 | 8.35 | 8.35 mg/l |
| 23 Jul 2025, 10:58 | 8.24 | 8.24 mg/l |
| 9 Jun 2025, 11:04 | 9.23 | 9.23 mg/l |
| 12 May 2025, 12:15 | 9.83 | 9.83 mg/l |
| 11 Apr 2025, 14:00 | 10.5 | 10.5 mg/l |
| 6 Mar 2024, 13:52 | 11.9 | 11.9 mg/l |
| 16 Feb 2024, 11:06 | 10.8 | 10.8 mg/l |
| 23 Jan 2024, 13:43 | 10.8 | 10.8 mg/l |
| 16 Jan 2024, 12:47 | 12.8 | 12.8 mg/l |
| 13 Dec 2023, 10:17 | 11 | 11 mg/l |
| 1 Dec 2023, 11:47 | 12.2 | 12.2 mg/l |
| 15 Nov 2023, 12:27 | 10.7 | 10.7 mg/l |
| 19 Oct 2023, 12:38 | 10.5 | 10.5 mg/l |
Water temperature
code 0076 · °C
10.4 °C
Sampled 24 Mar 2026, 6 months ago · 20 results banked
Every result (20)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 10.4 | 10.4 °C |
| 6 Feb 2026, 14:18 | 9.5 | 9.5 °C |
| 19 Jan 2026, 12:59 | 7.4 | 7.4 °C |
| 9 Dec 2025, 11:36 | 11.8 | 11.8 °C |
| 6 Nov 2025, 11:34 | 13.3 | 13.3 °C |
| 2 Oct 2025, 10:54 | 12.5 | 12.5 °C |
| 4 Sep 2025, 11:52 | 16.3 | 16.3 °C |
| 12 Aug 2025, 10:35 | 19.5 | 19.5 °C |
| 23 Jul 2025, 10:58 | 19.5 | 19.5 °C |
| 9 Jun 2025, 11:04 | 14.1 | 14.1 °C |
| 12 May 2025, 12:15 | 14.1 | 14.1 °C |
| 11 Apr 2025, 14:00 | 13 | 13 °C |
| 6 Mar 2024, 13:52 | 7.8 | 7.8 °C |
| 16 Feb 2024, 11:06 | 10.5 | 10.5 °C |
| 23 Jan 2024, 13:43 | 8.5 | 8.5 °C |
| 16 Jan 2024, 12:47 | 4.7 | 4.7 °C |
| 13 Dec 2023, 10:17 | 9.9 | 9.9 °C |
| 1 Dec 2023, 11:47 | 6.3 | 6.3 °C |
| 15 Nov 2023, 12:27 | 11.1 | 11.1 °C |
| 19 Oct 2023, 12:38 | 13.7 | 13.7 °C |
pH
code 0061
7.36
Sampled 24 Mar 2026, 6 months ago · 20 results banked
Every result (20)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 7.36 | 7.36 |
| 6 Feb 2026, 14:18 | 7.49 | 7.49 |
| 19 Jan 2026, 12:59 | 7.46 | 7.46 |
| 9 Dec 2025, 11:36 | 7.01 | 7.01 |
| 6 Nov 2025, 11:34 | 7.36 | 7.36 |
| 2 Oct 2025, 10:54 | 7.52 | 7.52 |
| 4 Sep 2025, 11:52 | 7.69 | 7.69 |
| 12 Aug 2025, 10:35 | 7.57 | 7.57 |
| 23 Jul 2025, 10:58 | 7.71 | 7.71 |
| 9 Jun 2025, 11:04 | 7.45 | 7.45 |
| 12 May 2025, 12:15 | 7.59 | 7.59 |
| 11 Apr 2025, 14:00 | 8.09 | 8.09 |
| 6 Mar 2024, 13:52 | 7.46 | 7.46 |
| 16 Feb 2024, 11:06 | 7.29 | 7.29 |
| 23 Jan 2024, 13:43 | 7.18 | 7.18 |
| 16 Jan 2024, 12:47 | 7.45 | 7.45 |
| 13 Dec 2023, 10:17 | 7.37 | 7.37 |
| 1 Dec 2023, 11:47 | 7.53 | 7.53 |
| 15 Nov 2023, 12:27 | 7.34 | 7.34 |
| 19 Oct 2023, 12:38 | 7.35 | 7.35 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
0.082 mg/l
Sampled 24 Mar 2026, 6 months ago · 20 results banked
Every result (20)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 0.082 | 0.082 mg/l |
| 6 Feb 2026, 14:18 | 0.067 | 0.067 mg/l |
| 19 Jan 2026, 12:59 | <0.03 | below 0.03 mg/l (not detected above this) |
| 9 Dec 2025, 11:36 | 0.056 | 0.056 mg/l |
| 6 Nov 2025, 11:34 | <0.03 | below 0.03 mg/l (not detected above this) |
| 2 Oct 2025, 10:54 | <0.03 | below 0.03 mg/l (not detected above this) |
| 4 Sep 2025, 11:52 | <0.03 | below 0.03 mg/l (not detected above this) |
| 12 Aug 2025, 10:35 | 0.042 | 0.042 mg/l |
| 23 Jul 2025, 10:58 | 0.044 | 0.044 mg/l |
| 9 Jun 2025, 11:04 | 0.055 | 0.055 mg/l |
| 12 May 2025, 12:15 | 0.033 | 0.033 mg/l |
| 11 Apr 2025, 14:00 | <0.03 | below 0.03 mg/l (not detected above this) |
| 6 Mar 2024, 13:52 | <0.03 | below 0.03 mg/l (not detected above this) |
| 16 Feb 2024, 11:06 | 0.088 | 0.088 mg/l |
| 23 Jan 2024, 13:43 | 0.069 | 0.069 mg/l |
| 16 Jan 2024, 12:47 | <0.03 | below 0.03 mg/l (not detected above this) |
| 13 Dec 2023, 10:17 | 0.046 | 0.046 mg/l |
| 1 Dec 2023, 11:47 | <0.03 | below 0.03 mg/l (not detected above this) |
| 15 Nov 2023, 12:27 | 0.035 | 0.035 mg/l |
| 19 Oct 2023, 12:38 | <0.03 | below 0.03 mg/l (not detected above this) |
Nitrate
as nitrogen (N) · code 0117 · mg/l
1.89 mg/l
Sampled 24 Mar 2026, 6 months ago · 20 results banked
Every result (20)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 1.89 | 1.89 mg/l |
| 6 Feb 2026, 14:18 | 1.79 | 1.79 mg/l |
| 19 Jan 2026, 12:59 | 2.69 | 2.69 mg/l |
| 9 Dec 2025, 11:36 | 1.5 | 1.5 mg/l |
| 6 Nov 2025, 11:34 | 2.5 | 2.5 mg/l |
| 2 Oct 2025, 10:54 | 1.7 | 1.7 mg/l |
| 4 Sep 2025, 11:52 | 1.1 | 1.1 mg/l |
| 12 Aug 2025, 10:35 | 1.1 | 1.1 mg/l |
| 23 Jul 2025, 10:58 | 1.19 | 1.19 mg/l |
| 9 Jun 2025, 11:04 | 1.29 | 1.29 mg/l |
| 12 May 2025, 12:15 | 1.9 | 1.9 mg/l |
| 11 Apr 2025, 14:00 | 1.5 | 1.5 mg/l |
| 6 Mar 2024, 13:52 | 2.59 | 2.59 mg/l |
| 16 Feb 2024, 11:06 | 1.49 | 1.49 mg/l |
| 23 Jan 2024, 13:43 | 2.09 | 2.09 mg/l |
| 16 Jan 2024, 12:47 | 2.79 | 2.79 mg/l |
| 13 Dec 2023, 10:17 | 2.39 | 2.39 mg/l |
| 1 Dec 2023, 11:47 | 2.59 | 2.59 mg/l |
| 15 Nov 2023, 12:27 | 2.39 | 2.39 mg/l |
| 19 Oct 2023, 12:38 | 2.5 | 2.5 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.022 mg/l
Sampled 24 Mar 2026, 6 months ago · 20 results banked
Every result (20)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 0.022 | 0.022 mg/l |
| 6 Feb 2026, 14:18 | 0.034 | 0.034 mg/l |
| 19 Jan 2026, 12:59 | 0.022 | 0.022 mg/l |
| 9 Dec 2025, 11:36 | 0.052 | 0.052 mg/l |
| 6 Nov 2025, 11:34 | 0.04 | 0.04 mg/l |
| 2 Oct 2025, 10:54 | 0.02 | 0.02 mg/l |
| 4 Sep 2025, 11:52 | 0.025 | 0.025 mg/l |
| 12 Aug 2025, 10:35 | <0.01 | below 0.01 mg/l (not detected above this) |
| 23 Jul 2025, 10:58 | 0.02 | 0.02 mg/l |
| 9 Jun 2025, 11:04 | 0.04 | 0.04 mg/l |
| 12 May 2025, 12:15 | 0.012 | 0.012 mg/l |
| 11 Apr 2025, 14:00 | <0.01 | below 0.01 mg/l (not detected above this) |
| 6 Mar 2024, 13:52 | 0.021 | 0.021 mg/l |
| 16 Feb 2024, 11:06 | 0.036 | 0.036 mg/l |
| 23 Jan 2024, 13:43 | 0.035 | 0.035 mg/l |
| 16 Jan 2024, 12:47 | 0.021 | 0.021 mg/l |
| 13 Dec 2023, 10:17 | 0.024 | 0.024 mg/l |
| 1 Dec 2023, 11:47 | 0.022 | 0.022 mg/l |
| 15 Nov 2023, 12:27 | 0.025 | 0.025 mg/l |
| 19 Oct 2023, 12:38 | 0.021 | 0.021 mg/l |
Turbidity
code 6396 · NTU
6.4 NTU
Sampled 24 Mar 2026, 6 months ago · 19 results banked
Every result (19)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 6.4 | 6.4 NTU |
| 6 Feb 2026, 14:18 | 43 | 43 NTU |
| 19 Jan 2026, 12:59 | 5 | 5 NTU |
| 9 Dec 2025, 11:36 | 80 | 80 NTU |
| 6 Nov 2025, 11:34 | 12 | 12 NTU |
| 2 Oct 2025, 10:54 | 4.2 | 4.2 NTU |
| 12 Aug 2025, 10:35 | 2.6 | 2.6 NTU |
| 23 Jul 2025, 10:58 | 5.6 | 5.6 NTU |
| 9 Jun 2025, 11:04 | 19 | 19 NTU |
| 12 May 2025, 12:15 | 3.3 | 3.3 NTU |
| 11 Apr 2025, 14:00 | 1.2 | 1.2 NTU |
| 6 Mar 2024, 13:52 | 6.3 | 6.3 NTU |
| 16 Feb 2024, 11:06 | 98 | 98 NTU |
| 23 Jan 2024, 13:43 | 23 | 23 NTU |
| 16 Jan 2024, 12:47 | 3.8 | 3.8 NTU |
| 13 Dec 2023, 10:17 | 25 | 25 NTU |
| 1 Dec 2023, 11:47 | 5.1 | 5.1 NTU |
| 15 Nov 2023, 12:27 | 20 | 20 NTU |
| 19 Oct 2023, 12:38 | 5.2 | 5.2 NTU |
Conductivity
at 25 °C · code 0077 · µS/cm
200 µS/cm
Sampled 24 Mar 2026, 6 months ago · 19 results banked
Every result (19)
| Sampled | Result as published | Reads as |
|---|---|---|
| 24 Mar 2026, 12:48 | 200 | 200 µS/cm |
| 6 Feb 2026, 14:18 | 150 | 150 µS/cm |
| 19 Jan 2026, 12:59 | 190 | 190 µS/cm |
| 9 Dec 2025, 11:36 | 130 | 130 µS/cm |
| 6 Nov 2025, 11:34 | 180 | 180 µS/cm |
| 2 Oct 2025, 10:54 | 220 | 220 µS/cm |
| 12 Aug 2025, 10:35 | 310 | 310 µS/cm |
| 23 Jul 2025, 10:58 | 350 | 350 µS/cm |
| 9 Jun 2025, 11:04 | 200 | 200 µS/cm |
| 12 May 2025, 12:15 | 280 | 280 µS/cm |
| 11 Apr 2025, 14:00 | 310 | 310 µS/cm |
| 6 Mar 2024, 13:52 | 180 | 180 µS/cm |
| 16 Feb 2024, 11:06 | 140 | 140 µS/cm |
| 23 Jan 2024, 13:43 | 200 | 200 µS/cm |
| 16 Jan 2024, 12:47 | 220 | 220 µS/cm |
| 13 Dec 2023, 10:17 | 180 | 180 µS/cm |
| 1 Dec 2023, 11:47 | 200 | 200 µS/cm |
| 15 Nov 2023, 12:27 | 190 | 190 µS/cm |
| 19 Oct 2023, 12:38 | 210 | 210 µS/cm |
Everything measured here
21 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 21 rows
| Determinand | Material | Results | First – last | Latest result |
|---|---|---|---|---|
| Oxygen, Dissolved, % Saturation 9901 | River water | 20 | Oct 2023 – Mar 2026 | 90.4% 24 Mar 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 20 | Oct 2023 – Mar 2026 | 10.1 mg/l 24 Mar 2026 |
| Temperature of Water 0076 | River water | 20 | Oct 2023 – Mar 2026 | 10.4 °C 24 Mar 2026 |
| pH 0061 | River water | 20 | Oct 2023 – Mar 2026 | 7.36 24 Mar 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 20 | Oct 2023 – Mar 2026 | 0.082 mg/l 24 Mar 2026 |
| Nitrate as N 0117 | River water | 20 | Oct 2023 – Mar 2026 | 1.89 mg/l 24 Mar 2026 |
| Orthophosphate, reactive as P 0180 | River water | 20 | Oct 2023 – Mar 2026 | 0.022 mg/l 24 Mar 2026 |
| Turbidity 6396 | River water | 19 | Oct 2023 – Mar 2026 | 6.4 NTU 24 Mar 2026 |
| Conductivity at 25 C 0077 | River water | 19 | Oct 2023 – Mar 2026 | 200 µS/cm 24 Mar 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 20 | Oct 2023 – Mar 2026 | 39 mg/l 24 Mar 2026 |
| Ammonia un-ionised as N 0119 | River water | 20 | Oct 2023 – Mar 2026 | 0.00036 mg/l 24 Mar 2026 |
| BOD : 5 Day ATU 0085 | River water | 19 | Oct 2023 – Mar 2026 | 1.1 mg/l 24 Mar 2026 |
| Chloride 0172 | River water | 20 | Oct 2023 – Mar 2026 | 19 mg/l 24 Mar 2026 |
| Chlorophyll : Acetone Extract 7887 | River water | 18 | Oct 2023 – Mar 2026 | 3 µg/l 24 Mar 2026 |
| Nitrite as N 0118 | River water | 20 | Oct 2023 – Mar 2026 | 0.0051 mg/l 24 Mar 2026 |
| Nitrogen, Total Inorganic : (Calculated) 3683 | River water | 20 | Oct 2023 – Mar 2026 | 1.98 mg/l 24 Mar 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 20 | Oct 2023 – Mar 2026 | 1.9 mg/l 24 Mar 2026 |
| Phosphate :- {TIP} 0192 | River water | 20 | Oct 2023 – Mar 2026 | 0.026 mg/l 24 Mar 2026 |
| Phosphorus, Total as P 0348 | River water | 20 | Oct 2023 – Mar 2026 | 0.04 mg/l 24 Mar 2026 |
| Solids, Suspended at 105 C 0135 | River water | 20 | Oct 2023 – Mar 2026 | 8.6 mg/l 24 Mar 2026 |
| Weather : Precipitation 1183 | River water | 20 | Oct 2023 – Mar 2026 | Light rain 24 Mar 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.