River Avill Dunster Castle
EA name: RIVER AVILL DUNSTER CASTLE (also listed as “RSN0679 RIVER AVILL DUNSTER CASTLE”)
Environment Agency sampling point SW-RSN0679 · 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
- 2 Sep 2026, 15:0229 days ago · time as the Environment Agency records it (UK clock time; the source gives no time zone)
- Samples banked
- 9 since 14 Jan 2026 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 299506, 143698As published, to the nearest 1 m. Open in a map
- River, by its own name
- Avill
- River, by the map
- River AvillPlaced on the river its name gives, 4 m from the line.
- Next gauge downstream
- None tracedThe map stops before any gauge.
- Why it was sampled
- Monitoring (national agency policy) (9 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
99.7%
Sampled 2 Sep 2026, 29 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 2 Sep 2026, 15:02 | 99.7 | 99.7% |
| 12 Aug 2026, 10:47 | 102.2 | 102.2% |
| 6 Jul 2026, 14:46 | 102.2 | 102.2% |
| 9 Jun 2026, 13:00 | 102.3 | 102.3% |
| 7 May 2026, 12:12 | 101.2 | 101.2% |
| 21 Apr 2026, 12:06 | 103.5 | 103.5% |
| 27 Mar 2026, 13:21 | 104.1 | 104.1% |
| 11 Feb 2026, 10:14 | 103.1 | 103.1% |
| 14 Jan 2026, 12:27 | 102 | 102% |
Dissolved oxygen
as O2 · code 9924 · mg/l
9.59 mg/l
Sampled 2 Sep 2026, 29 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 2 Sep 2026, 15:02 | 9.59 | 9.59 mg/l |
| 12 Aug 2026, 10:47 | 10 | 10 mg/l |
| 6 Jul 2026, 14:46 | 9.63 | 9.63 mg/l |
| 9 Jun 2026, 13:00 | 10.6 | 10.6 mg/l |
| 7 May 2026, 12:12 | 11 | 11 mg/l |
| 21 Apr 2026, 12:06 | 12 | 12 mg/l |
| 27 Mar 2026, 13:21 | 11.4 | 11.4 mg/l |
| 11 Feb 2026, 10:14 | 11.6 | 11.6 mg/l |
| 14 Jan 2026, 12:27 | 12.6 | 12.6 mg/l |
Water temperature
code 0076 · °C
17.1 °C
Sampled 2 Sep 2026, 29 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 2 Sep 2026, 15:02 | 17.1 | 17.1 °C |
| 12 Aug 2026, 10:47 | 16.2 | 16.2 °C |
| 6 Jul 2026, 14:46 | 18.1 | 18.1 °C |
| 9 Jun 2026, 13:00 | 13.5 | 13.5 °C |
| 7 May 2026, 12:12 | 11.5 | 11.5 °C |
| 21 Apr 2026, 12:06 | 8.9 | 8.9 °C |
| 27 Mar 2026, 13:21 | 11.1 | 11.1 °C |
| 11 Feb 2026, 10:14 | 10.1 | 10.1 °C |
| 14 Jan 2026, 12:27 | 6.2 | 6.2 °C |
pH
code 0061
8.16
Sampled 2 Sep 2026, 29 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 2 Sep 2026, 15:02 | 8.16 | 8.16 |
| 12 Aug 2026, 10:47 | 8.22 | 8.22 |
| 6 Jul 2026, 14:46 | 8.27 | 8.27 |
| 9 Jun 2026, 13:00 | 8.26 | 8.26 |
| 7 May 2026, 12:12 | 8.32 | 8.32 |
| 21 Apr 2026, 12:06 | 8.4 | 8.4 |
| 27 Mar 2026, 13:21 | 8.45 | 8.45 |
| 11 Feb 2026, 10:14 | 8.26 | 8.26 |
| 14 Jan 2026, 12:27 | 8.15 | 8.15 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
0.0033 mg/l
Sampled 2 Sep 2026, 29 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 2 Sep 2026, 15:02 | 0.0033 | 0.0033 mg/l |
| 12 Aug 2026, 10:47 | 0.0036 | 0.0036 mg/l |
| 6 Jul 2026, 14:46 | 0.0038 | 0.0038 mg/l |
| 9 Jun 2026, 13:00 | <0.002 | below 0.002 mg/l (not detected above this) |
| 7 May 2026, 12:12 | 0.0046 | 0.0046 mg/l |
| 21 Apr 2026, 12:06 | 0.011 | 0.011 mg/l |
| 27 Mar 2026, 13:21 | <0.002 | below 0.002 mg/l (not detected above this) |
| 11 Feb 2026, 10:14 | 0.004 | 0.004 mg/l |
| 14 Jan 2026, 12:27 | 0.0022 | 0.0022 mg/l |
Nitrate
as nitrogen (N) · code 0117 · mg/l
1.1 mg/l
Sampled 2 Sep 2026, 29 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 2 Sep 2026, 15:02 | 1.1 | 1.1 mg/l |
| 12 Aug 2026, 10:47 | 0.958 | 0.958 mg/l |
| 6 Jul 2026, 14:46 | 1.3 | 1.3 mg/l |
| 9 Jun 2026, 13:00 | 1.3 | 1.3 mg/l |
| 7 May 2026, 12:12 | 1.4 | 1.4 mg/l |
| 21 Apr 2026, 12:06 | 1.4 | 1.4 mg/l |
| 27 Mar 2026, 13:21 | 1.5 | 1.5 mg/l |
| 11 Feb 2026, 10:14 | 1.7 | 1.7 mg/l |
| 14 Jan 2026, 12:27 | 1.7 | 1.7 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.047 mg/l
Sampled 2 Sep 2026, 29 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 2 Sep 2026, 15:02 | 0.047 | 0.047 mg/l |
| 12 Aug 2026, 10:47 | 0.047 | 0.047 mg/l |
| 6 Jul 2026, 14:46 | 0.048 | 0.048 mg/l |
| 9 Jun 2026, 13:00 | 0.046 | 0.046 mg/l |
| 7 May 2026, 12:12 | 0.041 | 0.041 mg/l |
| 21 Apr 2026, 12:06 | 0.037 | 0.037 mg/l |
| 27 Mar 2026, 13:21 | 0.033 | 0.033 mg/l |
| 11 Feb 2026, 10:14 | 0.044 | 0.044 mg/l |
| 14 Jan 2026, 12:27 | 0.038 | 0.038 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
307 µS/cm
Sampled 2 Sep 2026, 29 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 2 Sep 2026, 15:02 | 307 | 307 µS/cm |
| 12 Aug 2026, 10:47 | 306 | 306 µS/cm |
| 6 Jul 2026, 14:46 | 287 | 287 µS/cm |
| 9 Jun 2026, 13:00 | 269 | 269 µS/cm |
| 7 May 2026, 12:12 | 270 | 270 µS/cm |
| 21 Apr 2026, 12:06 | 255 | 255 µS/cm |
| 27 Mar 2026, 13:21 | 238 | 238 µS/cm |
| 11 Feb 2026, 10:14 | 208 | 208 µS/cm |
| 14 Jan 2026, 12:27 | 232 | 232 µS/cm |
Everything measured here
18 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 18 rows
| Determinand | Material | Results | First – last | Latest result |
|---|---|---|---|---|
| Oxygen, Dissolved, % Saturation 9901 | River water | 9 | Jan 2026 – Sep 2026 | 99.7% 2 Sep 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 9 | Jan 2026 – Sep 2026 | 9.59 mg/l 2 Sep 2026 |
| Temperature of Water 0076 | River water | 9 | Jan 2026 – Sep 2026 | 17.1 °C 2 Sep 2026 |
| pH 0061 | River water | 9 | Jan 2026 – Sep 2026 | 8.16 2 Sep 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 9 | Jan 2026 – Sep 2026 | 0.0033 mg/l 2 Sep 2026 |
| Nitrate as N 0117 | River water | 9 | Jan 2026 – Sep 2026 | 1.1 mg/l 2 Sep 2026 |
| Orthophosphate, reactive as P 0180 | River water | 9 | Jan 2026 – Sep 2026 | 0.047 mg/l 2 Sep 2026 |
| Conductivity at 25 C 0077 | River water | 9 | Jan 2026 – Sep 2026 | 307 µS/cm 2 Sep 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 9 | Jan 2026 – Sep 2026 | 130 mg/l 2 Sep 2026 |
| Ammonia un-ionised as N 0119 | River water | 9 | Jan 2026 – Sep 2026 | 0.0001 mg/l 2 Sep 2026 |
| Carbon, Organic, Dissolved as C :- {DOC} 0301 | River water | 9 | Jan 2026 – Sep 2026 | 1.3 mg/l 2 Sep 2026 |
| Chloride 0172 | River water | 9 | Jan 2026 – Sep 2026 | 19 mg/l 2 Sep 2026 |
| Flow Type 2896 | River water | 9 | Jan 2026 – Sep 2026 | Moderate Flow 2 Sep 2026 |
| Nitrite as N 0118 | River water | 9 | Jan 2026 – Sep 2026 | 0.0022 mg/l 2 Sep 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 9 | Jan 2026 – Sep 2026 | 1.1 mg/l 2 Sep 2026 |
| Phosphorus, Total as P 0348 | River water | 9 | Jan 2026 – Sep 2026 | 0.089 mg/l 2 Sep 2026 |
| Silica, reactive as SiO2 0182 | River water | 9 | Jan 2026 – Sep 2026 | 5.7 mg/l 2 Sep 2026 |
| Solids, Suspended at 105 C 0135 | River water | 9 | Jan 2026 – Sep 2026 | 13 mg/l 2 Sep 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.