Chalvey Ditch above Thames
EA name: CHALVEY DITCH ABOVE THAMES
Environment Agency sampling point TH-PTHR0014 · 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
- 16 Jul 2026, 09:363 months ago · time as the Environment Agency records it (UK clock time; the source gives no time zone)
- Samples banked
- 21 since 6 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 497010, 178350As published, to the nearest 10 m. Open in a map
- River, by its own name
- Chalvey Ditch
- River, by the map
- Chalvey DitchPlaced on the river its name gives, 199 m from the line.
- Next gauge downstream
- Windsor Park On the River Thames · 1.8 km along the river
- Why it was sampled
- Environmental monitoring statutory (EU directives) (21 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
77.8%
Sampled 16 Jul 2026, 3 months ago · 21 results banked
Every result (21)
| Sampled | Result as published | Reads as |
|---|---|---|
| 16 Jul 2026, 09:36 | 77.8 | 77.8% |
| 15 Jun 2026, 11:28 | 77.5 | 77.5% |
| 7 May 2026, 11:24 | 87.6 | 87.6% |
| 13 Apr 2026, 12:57 | 84.8 | 84.8% |
| 26 Mar 2026, 10:32 | 93.3 | 93.3% |
| 13 Feb 2026, 09:15 | 78 | 78% |
| 27 Jan 2026, 11:52 | 86.3 | 86.3% |
| 11 Dec 2025, 10:29 | 70.2 | 70.2% |
| 24 Nov 2025, 11:07 | 65.2 | 65.2% |
| 29 Oct 2025, 09:46 | 69.8 | 69.8% |
| 3 Apr 2025, 11:05 | 91.4 | 91.4% |
| 10 Mar 2025, 12:47 | 94.8 | 94.8% |
| 19 Feb 2025, 09:57 | 88.3 | 88.3% |
| 9 Jan 2025, 11:10 | 81.4 | 81.4% |
| 6 Dec 2024, 11:56 | 74.4 | 74.4% |
| 15 Nov 2024, 13:36 | 81.3 | 81.3% |
| 7 Oct 2024, 11:22 | 83.4 | 83.4% |
| 5 Sep 2024, 12:34 | 85.9 | 85.9% |
| 16 Aug 2024, 10:44 | 87.2 | 87.2% |
| 3 Jul 2024, 10:16 | 83.2 | 83.2% |
| 6 Jun 2024, 12:11 | 86.7 | 86.7% |
Dissolved oxygen
as O2 · code 9924 · mg/l
7.47 mg/l
Sampled 16 Jul 2026, 3 months ago · 21 results banked
Every result (21)
| Sampled | Result as published | Reads as |
|---|---|---|
| 16 Jul 2026, 09:36 | 7.47 | 7.47 mg/l |
| 15 Jun 2026, 11:28 | 7.85 | 7.85 mg/l |
| 7 May 2026, 11:24 | 9.4 | 9.4 mg/l |
| 13 Apr 2026, 12:57 | 9.42 | 9.42 mg/l |
| 26 Mar 2026, 10:32 | 10.7 | 10.7 mg/l |
| 13 Feb 2026, 09:15 | 8.96 | 8.96 mg/l |
| 27 Jan 2026, 11:52 | 10.1 | 10.1 mg/l |
| 11 Dec 2025, 10:29 | 7.93 | 7.93 mg/l |
| 24 Nov 2025, 11:07 | 7.43 | 7.43 mg/l |
| 29 Oct 2025, 09:46 | 7.44 | 7.44 mg/l |
| 3 Apr 2025, 11:05 | 10 | 10 mg/l |
| 10 Mar 2025, 12:47 | 10.4 | 10.4 mg/l |
| 19 Feb 2025, 09:57 | 10.7 | 10.7 mg/l |
| 9 Jan 2025, 11:10 | 10 | 10 mg/l |
| 6 Dec 2024, 11:56 | 8.38 | 8.38 mg/l |
| 15 Nov 2024, 13:36 | 8.8 | 8.8 mg/l |
| 7 Oct 2024, 11:22 | 8.57 | 8.57 mg/l |
| 5 Sep 2024, 12:34 | 8.62 | 8.62 mg/l |
| 16 Aug 2024, 10:44 | 8.46 | 8.46 mg/l |
| 3 Jul 2024, 10:16 | 8.57 | 8.57 mg/l |
| 6 Jun 2024, 12:11 | 8.99 | 8.99 mg/l |
Water temperature
code 0076 · °C
17.2 °C
Sampled 16 Jul 2026, 3 months ago · 21 results banked
Every result (21)
| Sampled | Result as published | Reads as |
|---|---|---|
| 16 Jul 2026, 09:36 | 17.2 | 17.2 °C |
| 15 Jun 2026, 11:28 | 14.7 | 14.7 °C |
| 7 May 2026, 11:24 | 12.1 | 12.1 °C |
| 13 Apr 2026, 12:57 | 10.6 | 10.6 °C |
| 26 Mar 2026, 10:32 | 9.4 | 9.4 °C |
| 13 Feb 2026, 09:15 | 9.2 | 9.2 °C |
| 27 Jan 2026, 11:52 | 8.4 | 8.4 °C |
| 11 Dec 2025, 10:29 | 9.9 | 9.9 °C |
| 24 Nov 2025, 11:07 | 9.5 | 9.5 °C |
| 29 Oct 2025, 09:46 | 12.4 | 12.4 °C |
| 3 Apr 2025, 11:05 | 11.1 | 11.1 °C |
| 10 Mar 2025, 12:47 | 11.3 | 11.3 °C |
| 19 Feb 2025, 09:57 | 7 | 7 °C |
| 9 Jan 2025, 11:10 | 6.4 | 6.4 °C |
| 6 Dec 2024, 11:56 | 10 | 10 °C |
| 15 Nov 2024, 13:36 | 11.7 | 11.7 °C |
| 7 Oct 2024, 11:22 | 14 | 14 °C |
| 5 Sep 2024, 12:34 | 15.1 | 15.1 °C |
| 16 Aug 2024, 10:44 | 16.7 | 16.7 °C |
| 3 Jul 2024, 10:16 | 13.9 | 13.9 °C |
| 6 Jun 2024, 12:11 | 13.6 | 13.6 °C |
pH
code 0061
7.75
Sampled 16 Jul 2026, 3 months ago · 21 results banked
Every result (21)
| Sampled | Result as published | Reads as |
|---|---|---|
| 16 Jul 2026, 09:36 | 7.75 | 7.75 |
| 15 Jun 2026, 11:28 | 7.67 | 7.67 |
| 7 May 2026, 11:24 | 7.71 | 7.71 |
| 13 Apr 2026, 12:57 | 7.72 | 7.72 |
| 26 Mar 2026, 10:32 | 7.84 | 7.84 |
| 13 Feb 2026, 09:15 | 7.49 | 7.49 |
| 27 Jan 2026, 11:52 | 7.76 | 7.76 |
| 11 Dec 2025, 10:29 | 7.84 | 7.84 |
| 24 Nov 2025, 11:07 | 7.51 | 7.51 |
| 29 Oct 2025, 09:46 | 7.16 | 7.16 |
| 3 Apr 2025, 11:05 | 7.94 | 7.94 |
| 10 Mar 2025, 12:47 | 7.9 | 7.9 |
| 19 Feb 2025, 09:57 | 7.75 | 7.75 |
| 9 Jan 2025, 11:10 | 7.43 | 7.43 |
| 6 Dec 2024, 11:56 | 7.66 | 7.66 |
| 15 Nov 2024, 13:36 | 7.82 | 7.82 |
| 7 Oct 2024, 11:22 | 7.63 | 7.63 |
| 5 Sep 2024, 12:34 | 7.9 | 7.9 |
| 16 Aug 2024, 10:44 | 7.9 | 7.9 |
| 3 Jul 2024, 10:16 | 8.03 | 8.03 |
| 6 Jun 2024, 12:11 | 7.79 | 7.79 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
below 0.03 mg/l (not detected above this)
Sampled 16 Jul 2026, 3 months ago · 19 results banked
Every result (19)
| Sampled | Result as published | Reads as |
|---|---|---|
| 16 Jul 2026, 09:36 | <0.03 | below 0.03 mg/l (not detected above this) |
| 15 Jun 2026, 11:28 | <0.03 | below 0.03 mg/l (not detected above this) |
| 7 May 2026, 11:24 | <0.03 | below 0.03 mg/l (not detected above this) |
| 13 Apr 2026, 12:57 | 0.054 | 0.054 mg/l |
| 26 Mar 2026, 10:32 | 0.11 | 0.11 mg/l |
| 13 Feb 2026, 09:15 | 0.046 | 0.046 mg/l |
| 27 Jan 2026, 11:52 | 0.096 | 0.096 mg/l |
| 11 Dec 2025, 10:29 | 0.052 | 0.052 mg/l |
| 24 Nov 2025, 11:07 | 0.18 | 0.18 mg/l |
| 29 Oct 2025, 09:46 | <0.03 | below 0.03 mg/l (not detected above this) |
| 10 Mar 2025, 12:47 | 0.034 | 0.034 mg/l |
| 19 Feb 2025, 09:57 | 0.056 | 0.056 mg/l |
| 9 Jan 2025, 11:10 | 0.21 | 0.21 mg/l |
| 15 Nov 2024, 13:36 | <0.03 | below 0.03 mg/l (not detected above this) |
| 7 Oct 2024, 11:22 | 0.031 | 0.031 mg/l |
| 5 Sep 2024, 12:34 | <0.03 | below 0.03 mg/l (not detected above this) |
| 16 Aug 2024, 10:44 | <0.03 | below 0.03 mg/l (not detected above this) |
| 3 Jul 2024, 10:16 | <0.03 | below 0.03 mg/l (not detected above this) |
| 6 Jun 2024, 12:11 | <0.03 | below 0.03 mg/l (not detected above this) |
Nitrate
as nitrogen (N) · code 0117 · mg/l
3.49 mg/l
Sampled 16 Jul 2026, 3 months ago · 19 results banked
Every result (19)
| Sampled | Result as published | Reads as |
|---|---|---|
| 16 Jul 2026, 09:36 | 3.49 | 3.49 mg/l |
| 15 Jun 2026, 11:28 | 3.48 | 3.48 mg/l |
| 7 May 2026, 11:24 | 3.58 | 3.58 mg/l |
| 13 Apr 2026, 12:57 | 2.98 | 2.98 mg/l |
| 26 Mar 2026, 10:32 | 3.27 | 3.27 mg/l |
| 13 Feb 2026, 09:15 | 2.58 | 2.58 mg/l |
| 27 Jan 2026, 11:52 | 1.56 | 1.56 mg/l |
| 11 Dec 2025, 10:29 | 3.25 | 3.25 mg/l |
| 24 Nov 2025, 11:07 | 2.46 | 2.46 mg/l |
| 29 Oct 2025, 09:46 | 2.99 | 2.99 mg/l |
| 10 Mar 2025, 12:47 | 3.58 | 3.58 mg/l |
| 19 Feb 2025, 09:57 | 3.48 | 3.48 mg/l |
| 9 Jan 2025, 11:10 | 2.96 | 2.96 mg/l |
| 15 Nov 2024, 13:36 | 3.58 | 3.58 mg/l |
| 7 Oct 2024, 11:22 | 3.67 | 3.67 mg/l |
| 5 Sep 2024, 12:34 | 3.69 | 3.69 mg/l |
| 16 Aug 2024, 10:44 | 3.59 | 3.59 mg/l |
| 3 Jul 2024, 10:16 | 3.99 | 3.99 mg/l |
| 6 Jun 2024, 12:11 | 4.68 | 4.68 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.22 mg/l
Sampled 16 Jul 2026, 3 months ago · 19 results banked
Every result (19)
| Sampled | Result as published | Reads as |
|---|---|---|
| 16 Jul 2026, 09:36 | 0.22 | 0.22 mg/l |
| 15 Jun 2026, 11:28 | 0.13 | 0.13 mg/l |
| 7 May 2026, 11:24 | 0.12 | 0.12 mg/l |
| 13 Apr 2026, 12:57 | 0.097 | 0.097 mg/l |
| 26 Mar 2026, 10:32 | 0.09 | 0.09 mg/l |
| 13 Feb 2026, 09:15 | 0.077 | 0.077 mg/l |
| 27 Jan 2026, 11:52 | 0.081 | 0.081 mg/l |
| 11 Dec 2025, 10:29 | 0.12 | 0.12 mg/l |
| 24 Nov 2025, 11:07 | 0.1 | 0.1 mg/l |
| 29 Oct 2025, 09:46 | 0.12 | 0.12 mg/l |
| 10 Mar 2025, 12:47 | 0.084 | 0.084 mg/l |
| 19 Feb 2025, 09:57 | 0.087 | 0.087 mg/l |
| 9 Jan 2025, 11:10 | 0.11 | 0.11 mg/l |
| 15 Nov 2024, 13:36 | 0.12 | 0.12 mg/l |
| 7 Oct 2024, 11:22 | 0.11 | 0.11 mg/l |
| 5 Sep 2024, 12:34 | 0.11 | 0.11 mg/l |
| 16 Aug 2024, 10:44 | 0.12 | 0.12 mg/l |
| 3 Jul 2024, 10:16 | 0.12 | 0.12 mg/l |
| 6 Jun 2024, 12:11 | 0.11 | 0.11 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
742 µS/cm
Sampled 16 Jul 2026, 3 months ago · 21 results banked
Every result (21)
| Sampled | Result as published | Reads as |
|---|---|---|
| 16 Jul 2026, 09:36 | 742 | 742 µS/cm |
| 15 Jun 2026, 11:28 | 747 | 747 µS/cm |
| 7 May 2026, 11:24 | 765 | 765 µS/cm |
| 13 Apr 2026, 12:57 | 627 | 627 µS/cm |
| 26 Mar 2026, 10:32 | 670 | 670 µS/cm |
| 13 Feb 2026, 09:15 | 532 | 532 µS/cm |
| 27 Jan 2026, 11:52 | 351 | 351 µS/cm |
| 11 Dec 2025, 10:29 | 686 | 686 µS/cm |
| 24 Nov 2025, 11:07 | 658 | 658 µS/cm |
| 29 Oct 2025, 09:46 | 731 | 731 µS/cm |
| 3 Apr 2025, 11:05 | 676 | 676 µS/cm |
| 10 Mar 2025, 12:47 | 630 | 630 µS/cm |
| 19 Feb 2025, 09:57 | 623 | 623 µS/cm |
| 9 Jan 2025, 11:10 | 598 | 598 µS/cm |
| 6 Dec 2024, 11:56 | 565 | 565 µS/cm |
| 15 Nov 2024, 13:36 | 692 | 692 µS/cm |
| 7 Oct 2024, 11:22 | 668 | 668 µS/cm |
| 5 Sep 2024, 12:34 | 701 | 701 µS/cm |
| 16 Aug 2024, 10:44 | 684 | 684 µS/cm |
| 3 Jul 2024, 10:16 | 707 | 707 µS/cm |
| 6 Jun 2024, 12:11 | 718 | 718 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 | 21 | Jun 2024 – Jul 2026 | 77.8% 16 Jul 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 21 | Jun 2024 – Jul 2026 | 7.47 mg/l 16 Jul 2026 |
| Temperature of Water 0076 | River water | 21 | Jun 2024 – Jul 2026 | 17.2 °C 16 Jul 2026 |
| pH 0061 | River water | 21 | Jun 2024 – Jul 2026 | 7.75 16 Jul 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 19 | Jun 2024 – Jul 2026 | below 0.03 mg/l 16 Jul 2026 |
| Nitrate as N 0117 | River water | 19 | Jun 2024 – Jul 2026 | 3.49 mg/l 16 Jul 2026 |
| Orthophosphate, reactive as P 0180 | River water | 19 | Jun 2024 – Jul 2026 | 0.22 mg/l 16 Jul 2026 |
| Conductivity at 25 C 0077 | River water | 21 | Jun 2024 – Jul 2026 | 742 µS/cm 16 Jul 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 19 | Jun 2024 – Jul 2026 | 220 mg/l 16 Jul 2026 |
| Ammonia un-ionised as N 0119 | River water | 19 | Jun 2024 – Jul 2026 | below 0.00053 mg/l 16 Jul 2026 |
| BOD : 5 Day ATU 0085 | River water | 19 | Jun 2024 – Jul 2026 | 3.9 mg/l 16 Jul 2026 |
| Nitrite as N 0118 | River water | 19 | Jun 2024 – Jul 2026 | 0.013 mg/l 16 Jul 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 19 | Jun 2024 – Jul 2026 | 3.5 mg/l 16 Jul 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.