Knowle Green water level

Name: Knowle Green water level (Environment Agency)
Creator: Environment Agency
License: https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/

River gauge, River Ash, Surrey, United Kingdom

Directions

Within the normal range

Water level

0.51m Steady over the last 24 hours

Measured 17 Oct 2026, 22:30 BST (1 hour ago)

History

7 days 30 days

Water level Top of normal rangeBottom of normal range

What this means

The River Ash at Knowle Green is at 0.51 m, within its typical range.

The usual range here runs from 0.37 m to 0.81 m.

It has barely moved over the past 24 hours. In the last month it has stayed between 0.35 m and 0.76 m.

Autumn rain usually starts to lift rivers again after the summer low.

Compared with the normal range the agency publishes for this gauge. How to read levels

Key numbers

Normal range: 0.37 m – 0.81 m
Lowest and highest in 30 days: 0.35 m – 0.76 m
Highest on record: 1.16 mFebruary 12, 2014
Lowest on record: 0.28 mJanuary 4, 2003

Fishing and paddling

Paddlers and anglers can expect the river much as they know it, though a heavy shower upstream can change that within hours.

Flood alerts and warnings come from the Environment Agency.

About the River Ash

The River Ash is a small, shallow river in Surrey, England. Its course of 10 kilometres (6.2 mi) is just outside Greater London. Work has been carried out to re-align, clear and build up a small, Littleton head of water and create two backwaters. One backwater dates to the medieval period; the other to the 1990s. It flows as one of the six distributaries of the River Colne from the south of Staines Moor immediately south of the Staines Bypass eastwards through the rest of the borough of Spelthorne before meeting the River Thames.

Weather at the gauge

Rain in the last 3 days: 2.8 mm. Rain that falls upstream can take hours or days to show up at a river gauge.

17 Sat 14° 6° – Wind 26 km/h

18 Sun 14° 8° 1.4 mm, 66% Wind 23 km/h

19 Mon 14° 10° 1.2 mm, 75% Wind 12 km/h

20 Tue 13° 11° 2.9 mm, 45% Wind 11 km/h

21 Wed 14° 9° 0.9 mm, 56% Wind 19 km/h

22 Thu 15° 6° 2.1 mm, 43% Wind 18 km/h

23 Fri 14° 8° 15 mm, 74% Wind 36 km/h

Forecast: Open-Meteo

Sunrise 07:29 AM Sunset 06:07 PM Daylight 10 hr, 37 min First quarter 44%

Map

Other gauges on the River Ash

Gauge	Level	Compared with normal	24 hours	Distance
Staines AshRiver gauge, River Ash	0.10 m	Very high	±0	1.5 km
MardockRiver gauge, River Ash	0.10 m	Normal	±0	56 km
Little HadhamRiver gauge, River Ash	0.02 m	Normal	±0	65 km
Furneux PelhamRiver gauge, River Ash	0.07 m	Lowest on record	−0.01 m	69 km

Nearby gauges

Gauge	Level	Compared with normal	24 hours	Distance
StainesRiver gauge, River Thames	2.66 m	Low	−0.01 m	1.1 km
Staines Trading EstateRiver gauge, River Colne	1.18 m	Normal	±0	1.3 km
Pound Mill, StainesRiver gauge, Wraysbury River	0.09 m	Low	±0	1.4 km
Penton HookRiver gauge, River Thames	0.15 m	Normal	−0.01 m	1.8 km
Hythe EndRiver gauge, Colne Brook	0.44 m	Normal	−0.01 m	2.9 km
Bell WeirRiver gauge, River Thames	0.24 m	Very high	±0	2.9 km
Stanwell MillRiver gauge, River Colne	0.64 m	High	−0.02 m	3.9 km
Chertsey LockRiver gauge, River Thames	0.18 m	Normal	±0	4.5 km

Questions and answers

What is the typical range for the River Ash at Knowle Green?

The Environment Agency gives a typical range of 0.37 m to 0.81 m for this gauge.

Is the river level the same as the depth of the water?

No. The reading is measured from a fixed zero mark at the gauge, so 0.51 m on the gauge does not mean the water is that deep.

What is the water level of Knowle Green today?

On 17 Oct 2026, 22:30 BST, the water level was 0.51 m. Steady over the last 24 hours.

Is Knowle Green rising or falling?

Steady over the last 24 hours. Down 0.08 m over the last 7 days.

Is the level of Knowle Green normal?

Within the normal range. Compared with the normal range the agency publishes for this gauge.

What is the highest water level ever recorded at Knowle Green?

The highest level on record is 1.16 m on February 12, 2014. The lowest is 0.28 m on January 4, 2003.

How often is this data updated?

The Environment Agency publishes a new reading every 15 minutes. This page refreshes within minutes of each update.

For specialists

Station codes, datum, parameters, data quality and downloads

Operator: Environment Agency
Station code: ea:3115TH (Agency page)
Coordinates: 51.43093, -0.49662 (WGS84)
Vertical datum: station datum
Update interval: every 15 minutes
Licence: Open Government Licence v3.0. Contains Environment Agency data licensed under the Open Government Licence v3.0

Published series

Parameter	Last value	Time (UTC)	Quality
Water level	0.51 m	2026-10-17 21:30	Provisional

Download

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<iframe src="https://nivelmap.com/embed/1647?lang=en" width="360" height="230" style="border:0;max-width:100%" loading="lazy" title="Knowle Green water level"></iframe>

How to cite

Environment Agency: Knowle Green (ea:3115TH). Accessed October 17, 2026 via Nivelmap, https://nivelmap.com/en/united-kingdom/surrey/knowle-green

How we check values

Each reading is stored as published. We hold back values that jump faster than physically plausible and show the measurement time with every value.

Readings are provisional, can be delayed or wrong and are not a flood warning. Read the disclaimer