Grendon Brook Ryeholmes Bridge
EA name: GRENDON BK.RYEHOLMES BRIDGE
Environment Agency sampling point AN-GREN050R · 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
- 17 Sep 2026, 14:1614 days ago · time as the Environment Agency records it (UK clock time; the source gives no time zone)
- Samples banked
- 28 since 28 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) · results completed 19 Sep 2026
- Where
- National Grid 488305, 263305As published, to the nearest 1 m. Open in a map
- River, by its own name
- Grendon Brook
- River, by the map
- Grendon BrookPlaced on the river its name gives, 3 m from the line.
- Next gauge downstream
- Islip Sluice On the River Nene · 28 km along the river (the path rests on a repair to the map)
- Why it was sampled
- Environmental monitoring statutory (EU directives) (23 samples)
Monitoring (national agency policy) (5 samples)
Results here were completed a median of 9 days after the sample was taken (2 to 15 days, 13 samples).
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
87.1%
Sampled 17 Sep 2026, 14 days ago · 28 results banked
Every result (28)
| Sampled | Result as published | Reads as |
|---|---|---|
| 17 Sep 2026, 14:16 | 87.1 | 87.1% |
| 3 Aug 2026, 13:11 | 61.1 | 61.1% |
| 3 Jul 2026, 11:53 | 67 | 67% |
| 17 Jun 2026, 13:10 | 78.8 | 78.8% |
| 11 May 2026, 15:05 | 104.7 | 104.7% |
| 21 Apr 2026, 10:00 | 94.4 | 94.4% |
| 20 Mar 2026, 10:39 | 94.2 | 94.2% |
| 5 Feb 2026, 12:52 | 91.8 | 91.8% |
| 14 Jan 2026, 12:16 | 94.6 | 94.6% |
| 2 Dec 2025, 12:08 | 87.2 | 87.2% |
| 11 Nov 2025, 12:03 | 69.5 | 69.5% |
| 13 Oct 2025, 13:54 | 83.2 | 83.2% |
| 5 Sep 2025, 11:52 | 68.6 | 68.6% |
| 15 Aug 2025, 11:26 | 72.9 | 72.9% |
| 2 Jul 2025, 11:17 | 73.8 | 73.8% |
| 11 Jun 2025, 11:31 | 100.6 | 100.6% |
| 9 May 2025, 11:14 | 107.1 | 107.1% |
| 7 Apr 2025, 09:31 | 91.6 | 91.6% |
| 28 Mar 2025, 14:44 | 119.8 | 119.8% |
| 10 Mar 2025, 10:02 | 96.1 | 96.1% |
| 7 Feb 2025, 11:07 | 99.5 | 99.5% |
| 21 Jan 2025, 11:57 | 97.4 | 97.4% |
| 3 Dec 2024, 12:14 | 94 | 94% |
| 18 Nov 2024, 13:37 | 93.2 | 93.2% |
| 15 Oct 2024, 10:49 | 88.8 | 88.8% |
| 19 Aug 2024, 11:31 | 85.6 | 85.6% |
| 15 Jul 2024, 13:17 | 92.2 | 92.2% |
| 28 Jun 2024, 11:32 | 100.3 | 100.3% |
Dissolved oxygen
as O2 · code 9924 · mg/l
8.12 mg/l
Sampled 17 Sep 2026, 14 days ago · 28 results banked
Every result (28)
| Sampled | Result as published | Reads as |
|---|---|---|
| 17 Sep 2026, 14:16 | 8.12 | 8.12 mg/l |
| 3 Aug 2026, 13:11 | 5.85 | 5.85 mg/l |
| 3 Jul 2026, 11:53 | 6.54 | 6.54 mg/l |
| 17 Jun 2026, 13:10 | 7.6 | 7.6 mg/l |
| 11 May 2026, 15:05 | 11.5 | 11.5 mg/l |
| 21 Apr 2026, 10:00 | 10.8 | 10.8 mg/l |
| 20 Mar 2026, 10:39 | 10.5 | 10.5 mg/l |
| 5 Feb 2026, 12:52 | 11.4 | 11.4 mg/l |
| 14 Jan 2026, 12:16 | 12 | 12 mg/l |
| 2 Dec 2025, 12:08 | 10.2 | 10.2 mg/l |
| 11 Nov 2025, 12:03 | 7.7 | 7.7 mg/l |
| 13 Oct 2025, 13:54 | 9.05 | 9.05 mg/l |
| 5 Sep 2025, 11:52 | 6.99 | 6.99 mg/l |
| 15 Aug 2025, 11:26 | 6.88 | 6.88 mg/l |
| 2 Jul 2025, 11:17 | 6.9 | 6.9 mg/l |
| 11 Jun 2025, 11:31 | 9.88 | 9.88 mg/l |
| 9 May 2025, 11:14 | 11.6 | 11.6 mg/l |
| 7 Apr 2025, 09:31 | 10.9 | 10.9 mg/l |
| 28 Mar 2025, 14:44 | 13.2 | 13.2 mg/l |
| 10 Mar 2025, 10:02 | 11.4 | 11.4 mg/l |
| 7 Feb 2025, 11:07 | 12.9 | 12.9 mg/l |
| 21 Jan 2025, 11:57 | 12.3 | 12.3 mg/l |
| 3 Dec 2024, 12:14 | 11.1 | 11.1 mg/l |
| 18 Nov 2024, 13:37 | 10.9 | 10.9 mg/l |
| 15 Oct 2024, 10:49 | 9.77 | 9.77 mg/l |
| 19 Aug 2024, 11:31 | 8.63 | 8.63 mg/l |
| 15 Jul 2024, 13:17 | 9.29 | 9.29 mg/l |
| 28 Jun 2024, 11:32 | 9.67 | 9.67 mg/l |
Water temperature
code 0076 · °C
18.6 °C
Sampled 17 Sep 2026, 14 days ago · 28 results banked
Every result (28)
| Sampled | Result as published | Reads as |
|---|---|---|
| 17 Sep 2026, 14:16 | 18.6 | 18.6 °C |
| 3 Aug 2026, 13:11 | 17.3 | 17.3 °C |
| 3 Jul 2026, 11:53 | 16.4 | 16.4 °C |
| 17 Jun 2026, 13:10 | 17 | 17 °C |
| 11 May 2026, 15:05 | 11.1 | 11.1 °C |
| 21 Apr 2026, 10:00 | 9.4 | 9.4 °C |
| 20 Mar 2026, 10:39 | 10.3 | 10.3 °C |
| 5 Feb 2026, 12:52 | 6.2 | 6.2 °C |
| 14 Jan 2026, 12:16 | 5.2 | 5.2 °C |
| 2 Dec 2025, 12:08 | 8.6 | 8.6 °C |
| 11 Nov 2025, 12:03 | 10.7 | 10.7 °C |
| 13 Oct 2025, 13:54 | 11.5 | 11.5 °C |
| 5 Sep 2025, 11:52 | 14.4 | 14.4 °C |
| 15 Aug 2025, 11:26 | 18 | 18 °C |
| 2 Jul 2025, 11:17 | 18.5 | 18.5 °C |
| 11 Jun 2025, 11:31 | 16.1 | 16.1 °C |
| 9 May 2025, 11:14 | 11.6 | 11.6 °C |
| 7 Apr 2025, 09:31 | 7.9 | 7.9 °C |
| 28 Mar 2025, 14:44 | 11.1 | 11.1 °C |
| 10 Mar 2025, 10:02 | 7.7 | 7.7 °C |
| 7 Feb 2025, 11:07 | 4.5 | 4.5 °C |
| 21 Jan 2025, 11:57 | 5.3 | 5.3 °C |
| 3 Dec 2024, 12:14 | 8.1 | 8.1 °C |
| 18 Nov 2024, 13:37 | 8.3 | 8.3 °C |
| 15 Oct 2024, 10:49 | 11 | 11 °C |
| 19 Aug 2024, 11:31 | 14.9 | 14.9 °C |
| 15 Jul 2024, 13:17 | 14.9 | 14.9 °C |
| 28 Jun 2024, 11:32 | 17 | 17 °C |
pH
code 0061
7.59
Sampled 17 Sep 2026, 14 days ago · 28 results banked
Every result (28)
| Sampled | Result as published | Reads as |
|---|---|---|
| 17 Sep 2026, 14:16 | 7.59 | 7.59 |
| 3 Aug 2026, 13:11 | 7.67 | 7.67 |
| 3 Jul 2026, 11:53 | 7.75 | 7.75 |
| 17 Jun 2026, 13:10 | 7.85 | 7.85 |
| 11 May 2026, 15:05 | 8.15 | 8.15 |
| 21 Apr 2026, 10:00 | 8.11 | 8.11 |
| 20 Mar 2026, 10:39 | 8.09 | 8.09 |
| 5 Feb 2026, 12:52 | 8.03 | 8.03 |
| 14 Jan 2026, 12:16 | 8.09 | 8.09 |
| 2 Dec 2025, 12:08 | 7.89 | 7.89 |
| 11 Nov 2025, 12:03 | 7.74 | 7.74 |
| 13 Oct 2025, 13:54 | 7.9 | 7.9 |
| 5 Sep 2025, 11:52 | 7.67 | 7.67 |
| 15 Aug 2025, 11:26 | 7.59 | 7.59 |
| 2 Jul 2025, 11:17 | 7.97 | 7.97 |
| 11 Jun 2025, 11:31 | 8.05 | 8.05 |
| 9 May 2025, 11:14 | 8.22 | 8.22 |
| 7 Apr 2025, 09:31 | 8.24 | 8.24 |
| 28 Mar 2025, 14:44 | 8.31 | 8.31 |
| 10 Mar 2025, 10:02 | 8.19 | 8.19 |
| 7 Feb 2025, 11:07 | 8.25 | 8.25 |
| 21 Jan 2025, 11:57 | 8.32 | 8.32 |
| 3 Dec 2024, 12:14 | 8.25 | 8.25 |
| 18 Nov 2024, 13:37 | 8.18 | 8.18 |
| 15 Oct 2024, 10:49 | 7.98 | 7.98 |
| 19 Aug 2024, 11:31 | 7.98 | 7.98 |
| 15 Jul 2024, 13:17 | 8.09 | 8.09 |
| 28 Jun 2024, 11:32 | 8.39 | 8.39 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
below 0.03 mg/l (not detected above this)
Sampled 17 Sep 2026, 14 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 17 Sep 2026, 14:16 | <0.03 | below 0.03 mg/l (not detected above this) |
| 3 Aug 2026, 13:11 | <0.03 | below 0.03 mg/l (not detected above this) |
| 3 Jul 2026, 11:53 | <0.03 | below 0.03 mg/l (not detected above this) |
| 17 Jun 2026, 13:10 | <0.03 | below 0.03 mg/l (not detected above this) |
| 11 May 2026, 15:05 | <0.03 | below 0.03 mg/l (not detected above this) |
| 21 Apr 2026, 10:00 | 0.05 | 0.05 mg/l |
| 20 Mar 2026, 10:39 | 0.066 | 0.066 mg/l |
| 5 Feb 2026, 12:52 | 0.039 | 0.039 mg/l |
| 14 Jan 2026, 12:16 | <0.03 | below 0.03 mg/l (not detected above this) |
| 2 Dec 2025, 12:08 | 0.067 | 0.067 mg/l |
| 11 Nov 2025, 12:03 | <0.03 | below 0.03 mg/l (not detected above this) |
| 13 Oct 2025, 13:54 | <0.03 | below 0.03 mg/l (not detected above this) |
| 5 Sep 2025, 11:52 | <0.03 | below 0.03 mg/l (not detected above this) |
| 15 Aug 2025, 11:26 | <0.03 | below 0.03 mg/l (not detected above this) |
| 2 Jul 2025, 11:17 | 0.048 | 0.048 mg/l |
| 11 Jun 2025, 11:31 | <0.03 | below 0.03 mg/l (not detected above this) |
| 9 May 2025, 11:14 | <0.03 | below 0.03 mg/l (not detected above this) |
| 28 Mar 2025, 14:44 | 0.056 | 0.056 mg/l |
| 10 Mar 2025, 10:02 | <0.03 | below 0.03 mg/l (not detected above this) |
| 7 Feb 2025, 11:07 | 0.049 | 0.049 mg/l |
| 21 Jan 2025, 11:57 | 0.064 | 0.064 mg/l |
| 3 Dec 2024, 12:14 | 0.055 | 0.055 mg/l |
| 18 Nov 2024, 13:37 | 0.033 | 0.033 mg/l |
| 15 Oct 2024, 10:49 | 0.036 | 0.036 mg/l |
| 19 Aug 2024, 11:31 | <0.03 | below 0.03 mg/l (not detected above this) |
| 15 Jul 2024, 13:17 | <0.03 | below 0.03 mg/l (not detected above this) |
| 28 Jun 2024, 11:32 | <0.03 | below 0.03 mg/l (not detected above this) |
Nitrate
as nitrogen (N) · code 0117 · mg/l
16 mg/l
Sampled 17 Sep 2026, 14 days ago · 27 results banked
Every result (27)
| Sampled | Result as published | Reads as |
|---|---|---|
| 17 Sep 2026, 14:16 | 16 | 16 mg/l |
| 3 Aug 2026, 13:11 | 5.69 | 5.69 mg/l |
| 3 Jul 2026, 11:53 | 6.29 | 6.29 mg/l |
| 17 Jun 2026, 13:10 | 5.78 | 5.78 mg/l |
| 11 May 2026, 15:05 | 7.48 | 7.48 mg/l |
| 21 Apr 2026, 10:00 | 9.14 | 9.14 mg/l |
| 20 Mar 2026, 10:39 | 10.9 | 10.9 mg/l |
| 5 Feb 2026, 12:52 | 14 | 14 mg/l |
| 14 Jan 2026, 12:16 | 14.9 | 14.9 mg/l |
| 2 Dec 2025, 12:08 | 24.9 | 24.9 mg/l |
| 11 Nov 2025, 12:03 | 7.27 | 7.27 mg/l |
| 13 Oct 2025, 13:54 | 8.8 | 8.8 mg/l |
| 5 Sep 2025, 11:52 | 8.69 | 8.69 mg/l |
| 15 Aug 2025, 11:26 | 7.79 | 7.79 mg/l |
| 2 Jul 2025, 11:17 | 7.37 | 7.37 mg/l |
| 11 Jun 2025, 11:31 | 5.89 | 5.89 mg/l |
| 9 May 2025, 11:14 | 5.27 | 5.27 mg/l |
| 28 Mar 2025, 14:44 | 7.8 | 7.8 mg/l |
| 10 Mar 2025, 10:02 | 8.57 | 8.57 mg/l |
| 7 Feb 2025, 11:07 | 9.35 | 9.35 mg/l |
| 21 Jan 2025, 11:57 | 9.13 | 9.13 mg/l |
| 3 Dec 2024, 12:14 | 8.76 | 8.76 mg/l |
| 18 Nov 2024, 13:37 | 9.42 | 9.42 mg/l |
| 15 Oct 2024, 10:49 | 8.05 | 8.05 mg/l |
| 19 Aug 2024, 11:31 | 9.87 | 9.87 mg/l |
| 15 Jul 2024, 13:17 | 7.06 | 7.06 mg/l |
| 28 Jun 2024, 11:32 | 8.17 | 8.17 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.25 mg/l
Sampled 17 Sep 2026, 14 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 17 Sep 2026, 14:16 | 0.25 | 0.25 mg/l |
| 3 Aug 2026, 13:11 | 1.9 | 1.9 mg/l |
| 3 Jul 2026, 11:53 | 1.5 | 1.5 mg/l |
| 17 Jun 2026, 13:10 | 0.97 | 0.97 mg/l |
| 11 May 2026, 15:05 | 0.86 | 0.86 mg/l |
| 21 Apr 2026, 10:00 | 0.66 | 0.66 mg/l |
| 20 Mar 2026, 10:39 | 0.086 | 0.086 mg/l |
| 5 Feb 2026, 12:52 | 0.084 | 0.084 mg/l |
| 14 Jan 2026, 12:16 | 0.19 | 0.19 mg/l |
| 2 Dec 2025, 12:08 | 0.3 | 0.3 mg/l |
| 11 Nov 2025, 12:03 | 1.5 | 1.5 mg/l |
| 13 Oct 2025, 13:54 | 1.7 | 1.7 mg/l |
| 5 Sep 2025, 11:52 | 2.1 | 2.1 mg/l |
| 15 Aug 2025, 11:26 | 1.8 | 1.8 mg/l |
| 2 Jul 2025, 11:17 | 1.7 | 1.7 mg/l |
| 11 Jun 2025, 11:31 | 0.93 | 0.93 mg/l |
| 9 May 2025, 11:14 | 0.48 | 0.48 mg/l |
| 28 Mar 2025, 14:44 | 0.34 | 0.34 mg/l |
| 10 Mar 2025, 10:02 | 0.22 | 0.22 mg/l |
| 7 Feb 2025, 11:07 | 0.16 | 0.16 mg/l |
| 21 Jan 2025, 11:57 | 0.19 | 0.19 mg/l |
| 18 Nov 2024, 13:37 | 0.49 | 0.49 mg/l |
| 15 Oct 2024, 10:49 | 0.13 | 0.13 mg/l |
| 19 Aug 2024, 11:31 | 1.5 | 1.5 mg/l |
| 15 Jul 2024, 13:17 | 0.73 | 0.73 mg/l |
| 28 Jun 2024, 11:32 | 0.82 | 0.82 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
851 µS/cm
Sampled 17 Sep 2026, 14 days ago · 28 results banked
Every result (28)
| Sampled | Result as published | Reads as |
|---|---|---|
| 17 Sep 2026, 14:16 | 851 | 851 µS/cm |
| 3 Aug 2026, 13:11 | 1007 | 1007 µS/cm |
| 3 Jul 2026, 11:53 | 975 | 975 µS/cm |
| 17 Jun 2026, 13:10 | 863 | 863 µS/cm |
| 11 May 2026, 15:05 | 885 | 885 µS/cm |
| 21 Apr 2026, 10:00 | 871 | 871 µS/cm |
| 20 Mar 2026, 10:39 | 732 | 732 µS/cm |
| 5 Feb 2026, 12:52 | 683 | 683 µS/cm |
| 14 Jan 2026, 12:16 | 771 | 771 µS/cm |
| 2 Dec 2025, 12:08 | 761 | 761 µS/cm |
| 11 Nov 2025, 12:03 | 893 | 893 µS/cm |
| 13 Oct 2025, 13:54 | 954 | 954 µS/cm |
| 5 Sep 2025, 11:52 | 861 | 861 µS/cm |
| 15 Aug 2025, 11:26 | 985 | 985 µS/cm |
| 2 Jul 2025, 11:17 | 969 | 969 µS/cm |
| 11 Jun 2025, 11:31 | 819 | 819 µS/cm |
| 9 May 2025, 11:14 | 781 | 781 µS/cm |
| 7 Apr 2025, 09:31 | 836 | 836 µS/cm |
| 28 Mar 2025, 14:44 | 845 | 845 µS/cm |
| 10 Mar 2025, 10:02 | 812 | 812 µS/cm |
| 7 Feb 2025, 11:07 | 783 | 783 µS/cm |
| 21 Jan 2025, 11:57 | 797 | 797 µS/cm |
| 3 Dec 2024, 12:14 | 722 | 722 µS/cm |
| 18 Nov 2024, 13:37 | 864 | 864 µS/cm |
| 15 Oct 2024, 10:49 | 708 | 708 µS/cm |
| 19 Aug 2024, 11:31 | 936 | 936 µS/cm |
| 15 Jul 2024, 13:17 | 830 | 830 µS/cm |
| 28 Jun 2024, 11:32 | 901 | 901 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 | 28 | Jun 2024 – Sep 2026 | 87.1% 17 Sep 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 28 | Jun 2024 – Sep 2026 | 8.12 mg/l 17 Sep 2026 |
| Temperature of Water 0076 | River water | 28 | Jun 2024 – Sep 2026 | 18.6 °C 17 Sep 2026 |
| pH 0061 | River water | 28 | Jun 2024 – Sep 2026 | 7.59 17 Sep 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 27 | Jun 2024 – Sep 2026 | below 0.03 mg/l 17 Sep 2026 |
| Nitrate as N 0117 | River water | 27 | Jun 2024 – Sep 2026 | 16 mg/l 17 Sep 2026 |
| Orthophosphate, reactive as P 0180 | River water | 26 | Jun 2024 – Sep 2026 | 0.25 mg/l 17 Sep 2026 |
| Conductivity at 25 C 0077 | River water | 28 | Jun 2024 – Sep 2026 | 851 µS/cm 17 Sep 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 26 | Jun 2024 – Sep 2026 | 120 mg/l 17 Sep 2026 |
| Ammonia un-ionised as N 0119 | River water | 27 | Jun 2024 – Sep 2026 | below 0.00041 mg/l 17 Sep 2026 |
| BOD : 5 Day ATU 0085 | River water | 23 | Jun 2024 – May 2026 | 1.7 mg/l 11 May 2026 |
| Nitrite as N 0118 | River water | 27 | Jun 2024 – Sep 2026 | 0.037 mg/l 17 Sep 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 27 | Jun 2024 – Sep 2026 | 16 mg/l 17 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.