Small River Lee below Windmill Lane- Small River Lee
EA name: SML R.LEE BELOW WINDMILL LANE- SML R.LEE (also listed as “RSN1689 SMALL RIVER LEE BELOW WINDMILL LANE- SMALL RIVER LEE”)
Environment Agency sampling point TH-RSN1689 · 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
- 1 Sep 2026, 06:5737 days ago · time as the Environment Agency records it (UK clock time; the source gives no time zone)
- Samples banked
- 10 since 16 Jan 2026 Imported periods: 1 Oct 2023 – 8 Oct 2026. Samples outside them are not shown here.
- Latest sample
- River / running surface water Monitoring (national agency policy)
- Where
- National Grid 536765, 202255As published, to the nearest 1 m. Open in a map
- River, by its own name
- Small Lee
- River, by the map
- Small River LeePlaced on the river its name gives, 2 m from the line.
- Next gauge downstream
- Enfield, Ordance Road On the Small River Lee · 4.1 km along the river
- Nearest gauge upstream
- Cheshunt, Windmill Lane On the Small River Lee · 0.1 km along the river
- Why it was sampled
- Monitoring (national agency policy) (10 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
35.3%
Sampled 1 Sep 2026, 37 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 1 Sep 2026, 06:57 | 35.3 | 35.3% |
| 13 Aug 2026, 09:53 | 43.9 | 43.9% |
| 7 Jul 2026, 12:39 | 73.2 | 73.2% |
| 5 Jun 2026, 12:04 | 56.2 | 56.2% |
| 14 May 2026, 08:04 | 51.7 | 51.7% |
| 15 Apr 2026, 07:54 | 59.1 | 59.1% |
| 3 Mar 2026, 07:55 | 84.2 | 84.2% |
| 3 Feb 2026, 08:01 | 91.4 | 91.4% |
| 16 Jan 2026, 07:52 | 92.2 | 92.2% |
Dissolved oxygen
as O2 · code 9924 · mg/l
3.52 mg/l
Sampled 1 Sep 2026, 37 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 1 Sep 2026, 06:57 | 3.52 | 3.52 mg/l |
| 13 Aug 2026, 09:53 | 4.1 | 4.1 mg/l |
| 7 Jul 2026, 12:39 | 6.56 | 6.56 mg/l |
| 5 Jun 2026, 12:04 | 5.59 | 5.59 mg/l |
| 14 May 2026, 08:04 | 5.94 | 5.94 mg/l |
| 15 Apr 2026, 07:54 | 6.41 | 6.41 mg/l |
| 3 Mar 2026, 07:55 | 10 | 10 mg/l |
| 3 Feb 2026, 08:01 | 11.2 | 11.2 mg/l |
| 16 Jan 2026, 07:52 | 11.5 | 11.5 mg/l |
Water temperature
code 0076 · °C
15.4 °C
Sampled 1 Sep 2026, 37 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 1 Sep 2026, 06:57 | 15.4 | 15.4 °C |
| 13 Aug 2026, 09:53 | 18.5 | 18.5 °C |
| 7 Jul 2026, 12:39 | 20.6 | 20.6 °C |
| 5 Jun 2026, 12:04 | 15.5 | 15.5 °C |
| 14 May 2026, 08:04 | 9.2 | 9.2 °C |
| 15 Apr 2026, 07:54 | 11.6 | 11.6 °C |
| 3 Mar 2026, 07:55 | 7.8 | 7.8 °C |
| 3 Feb 2026, 08:01 | 6.6 | 6.6 °C |
| 16 Jan 2026, 07:52 | 5.8 | 5.8 °C |
pH
code 0061
7.55
Sampled 1 Sep 2026, 37 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 1 Sep 2026, 06:57 | 7.55 | 7.55 |
| 13 Aug 2026, 09:53 | 7.49 | 7.49 |
| 7 Jul 2026, 12:39 | 7.71 | 7.71 |
| 5 Jun 2026, 12:04 | 7.68 | 7.68 |
| 14 May 2026, 08:04 | 7.6 | 7.6 |
| 15 Apr 2026, 07:54 | 7.75 | 7.75 |
| 3 Mar 2026, 07:55 | 7.77 | 7.77 |
| 3 Feb 2026, 08:01 | 7.88 | 7.88 |
| 16 Jan 2026, 07:52 | 7.86 | 7.86 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
0.39 mg/l
Sampled 1 Sep 2026, 37 days ago · 8 results banked
Every result (8)
| Sampled | Result as published | Reads as |
|---|---|---|
| 1 Sep 2026, 06:57 | 0.39 | 0.39 mg/l |
| 13 Aug 2026, 09:53 | 0.58 | 0.58 mg/l |
| 7 Jul 2026, 12:39 | <0.03 | below 0.03 mg/l (not detected above this) |
| 5 Jun 2026, 12:04 | 0.22 | 0.22 mg/l |
| 15 Apr 2026, 07:54 | 0.19 | 0.19 mg/l |
| 3 Mar 2026, 07:55 | 0.079 | 0.079 mg/l |
| 3 Feb 2026, 08:01 | 0.072 | 0.072 mg/l |
| 16 Jan 2026, 07:52 | 0.084 | 0.084 mg/l |
Nitrate
as nitrogen (N) · code 0117 · mg/l
0.98 mg/l
Sampled 1 Sep 2026, 37 days ago · 8 results banked
Every result (8)
| Sampled | Result as published | Reads as |
|---|---|---|
| 1 Sep 2026, 06:57 | 0.98 | 0.98 mg/l |
| 13 Aug 2026, 09:53 | 1.05 | 1.05 mg/l |
| 7 Jul 2026, 12:39 | 0.37 | 0.37 mg/l |
| 5 Jun 2026, 12:04 | 0.692 | 0.692 mg/l |
| 15 Apr 2026, 07:54 | 1.63 | 1.63 mg/l |
| 3 Mar 2026, 07:55 | 1.66 | 1.66 mg/l |
| 3 Feb 2026, 08:01 | 2.38 | 2.38 mg/l |
| 16 Jan 2026, 07:52 | 3.09 | 3.09 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.39 mg/l
Sampled 1 Sep 2026, 37 days ago · 8 results banked
Every result (8)
| Sampled | Result as published | Reads as |
|---|---|---|
| 1 Sep 2026, 06:57 | 0.39 | 0.39 mg/l |
| 13 Aug 2026, 09:53 | 0.5 | 0.5 mg/l |
| 7 Jul 2026, 12:39 | 0.4 | 0.4 mg/l |
| 5 Jun 2026, 12:04 | 0.42 | 0.42 mg/l |
| 15 Apr 2026, 07:54 | 0.26 | 0.26 mg/l |
| 3 Mar 2026, 07:55 | 0.15 | 0.15 mg/l |
| 3 Feb 2026, 08:01 | 0.16 | 0.16 mg/l |
| 16 Jan 2026, 07:52 | 0.17 | 0.17 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
656 µS/cm
Sampled 1 Sep 2026, 37 days ago · 9 results banked
Every result (9)
| Sampled | Result as published | Reads as |
|---|---|---|
| 1 Sep 2026, 06:57 | 656 | 656 µS/cm |
| 13 Aug 2026, 09:53 | 791 | 791 µS/cm |
| 7 Jul 2026, 12:39 | 804 | 804 µS/cm |
| 5 Jun 2026, 12:04 | 566 | 566 µS/cm |
| 14 May 2026, 08:04 | 538 | 538 µS/cm |
| 15 Apr 2026, 07:54 | 748 | 748 µS/cm |
| 3 Mar 2026, 07:55 | 624 | 624 µS/cm |
| 3 Feb 2026, 08:01 | 586 | 586 µS/cm |
| 16 Jan 2026, 07:52 | 503 | 503 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 | 9 | Jan 2026 – Sep 2026 | 35.3% 1 Sep 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 9 | Jan 2026 – Sep 2026 | 3.52 mg/l 1 Sep 2026 |
| Temperature of Water 0076 | River water | 9 | Jan 2026 – Sep 2026 | 15.4 °C 1 Sep 2026 |
| pH 0061 | River water | 9 | Jan 2026 – Sep 2026 | 7.55 1 Sep 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 8 | Jan 2026 – Sep 2026 | 0.39 mg/l 1 Sep 2026 |
| Nitrate as N 0117 | River water | 8 | Jan 2026 – Sep 2026 | 0.98 mg/l 1 Sep 2026 |
| Orthophosphate, reactive as P 0180 | River water | 8 | Jan 2026 – Sep 2026 | 0.39 mg/l 1 Sep 2026 |
| Conductivity at 25 C 0077 | River water | 9 | Jan 2026 – Sep 2026 | 656 µS/cm 1 Sep 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 8 | Jan 2026 – Sep 2026 | 190 mg/l 1 Sep 2026 |
| Ammonia un-ionised as N 0119 | River water | 8 | Jan 2026 – Sep 2026 | 0.00381 mg/l 1 Sep 2026 |
| Carbon, Organic, Dissolved as C :- {DOC} 0301 | River water | 8 | Jan 2026 – Sep 2026 | 7.7 mg/l 1 Sep 2026 |
| Chloride 0172 | River water | 8 | Jan 2026 – Sep 2026 | 50 mg/l 1 Sep 2026 |
| Flow Type 2896 | River water | 9 | Jan 2026 – Sep 2026 | Low Flow 1 Sep 2026 |
| GCMS Screen : Target Based multi-residue screening : Semi Quantitative 4994 | River water | 3 | Feb 2026 – Aug 2026 | 1 text result 13 Aug 2026 |
| LCMS Screen : Semi Quantitative 7299 | River water | 1 | Aug 2026 – Aug 2026 | 1 text result 13 Aug 2026 |
| Nitrite as N 0118 | River water | 8 | Jan 2026 – Sep 2026 | 0.12 mg/l 1 Sep 2026 |
| Nitrogen, Total as N 9686 | River water | 8 | Jan 2026 – Sep 2026 | 2.1 mg/l 1 Sep 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 8 | Jan 2026 – Sep 2026 | 1.1 mg/l 1 Sep 2026 |
| Phosphorus, Total as P 0348 | River water | 8 | Jan 2026 – Sep 2026 | 0.42 mg/l 1 Sep 2026 |
| Silica, reactive as SiO2 0182 | River water | 8 | Jan 2026 – Sep 2026 | 12 mg/l 1 Sep 2026 |
| Solids, Suspended at 105 C 0135 | River water | 8 | Jan 2026 – Sep 2026 | 8.8 mg/l 1 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.