River level Cannon Brook at Howletts Lane, Ruislip (TEMP)

Check for flood warnings in this area

Latest recorded level 0.14m at 9:45am Wednesday 28 July 2021.

River levels at this location in the last 5 days

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• Measured level
• When the water level reaches 0.82m here, minor flooding is possible in this area
• Highest recorded level. Hide
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Observed data

DateTime	Value	Error
2021-07-28T08:45Z	0.138	false
2021-07-28T08:30Z	0.139	false
2021-07-28T08:15Z	0.139	false
2021-07-28T08:00Z	0.139	false
2021-07-28T07:45Z	0.139	false
2021-07-28T07:30Z	0.139	false
2021-07-28T07:15Z	0.139	false
2021-07-28T07:00Z	0.139	false
2021-07-28T06:45Z	0.139	false
2021-07-28T06:30Z	0.139	false
2021-07-28T06:15Z	0.14	false
2021-07-28T06:00Z	0.14	false
2021-07-28T05:45Z	0.139	false
2021-07-28T05:30Z	0.139	false
2021-07-28T05:15Z	0.139	false
2021-07-28T05:00Z	0.139	false
2021-07-28T04:45Z	0.139	false
2021-07-28T04:30Z	0.139	false
2021-07-28T04:15Z	0.139	false
2021-07-28T04:00Z	0.139	false
2021-07-28T03:45Z	0.14	false
2021-07-28T03:30Z	0.14	false
2021-07-28T03:15Z	0.14	false
2021-07-28T03:00Z	0.14	false
2021-07-28T02:45Z	0.14	false
2021-07-28T02:30Z	0.14	false
2021-07-28T02:15Z	0.14	false
2021-07-28T02:00Z	0.14	false
2021-07-28T01:45Z	0.14	false
2021-07-28T01:30Z	0.141	false
2021-07-28T01:15Z	0.141	false
2021-07-28T01:00Z	0.141	false
2021-07-28T00:45Z	0.141	false
2021-07-28T00:30Z	0.141	false
2021-07-28T00:15Z	0.141	false
2021-07-28T00:00Z	0.141	false
2021-07-27T23:45Z	0.142	false
2021-07-27T23:30Z	0.142	false
2021-07-27T23:15Z	0.142	false
2021-07-27T23:00Z	0.143	false
2021-07-27T22:45Z	0.143	false
2021-07-27T22:30Z	0.143	false
2021-07-27T22:15Z	0.143	false
2021-07-27T22:00Z	0.143	false
2021-07-27T21:45Z	0.144	false
2021-07-27T21:30Z	0.144	false
2021-07-27T21:15Z	0.145	false
2021-07-27T21:00Z	0.146	false
2021-07-27T20:45Z	0.147	false
2021-07-27T20:30Z	0.148	false
2021-07-27T20:15Z	0.149	false
2021-07-27T20:00Z	0.149	false
2021-07-27T19:45Z	0.15	false
2021-07-27T19:30Z	0.151	false
2021-07-27T19:15Z	0.152	false
2021-07-27T19:00Z	0.154	false
2021-07-27T18:45Z	0.156	false
2021-07-27T18:30Z	0.157	false
2021-07-27T18:15Z	0.16	false
2021-07-27T18:00Z	0.164	false
2021-07-27T17:45Z	0.169	false
2021-07-27T17:30Z	0.176	false
2021-07-27T17:15Z	0.184	false
2021-07-27T17:00Z	0.198	false
2021-07-27T16:45Z	0.227	false
2021-07-27T16:30Z	0.262	false
2021-07-27T16:15Z	0.271	false
2021-07-27T16:00Z	0.418	false
2021-07-27T15:45Z	0.163	false
2021-07-27T15:30Z	0.133	false
2021-07-27T15:15Z	0.133	false
2021-07-27T15:00Z	0.133	false
2021-07-27T14:45Z	0.133	false
2021-07-27T14:30Z	0.133	false
2021-07-27T14:15Z	0.133	false
2021-07-27T14:00Z	0.133	false
2021-07-27T13:45Z	0.133	false
2021-07-27T13:30Z	0.134	false
2021-07-27T13:15Z	0.134	false
2021-07-27T13:00Z	0.134	false
2021-07-27T12:45Z	0.135	false
2021-07-27T12:30Z	0.135	false
2021-07-27T12:15Z	0.134	false
2021-07-27T12:00Z	0.134	false
2021-07-27T11:45Z	0.135	false
2021-07-27T11:30Z	0.134	false
2021-07-27T11:15Z	0.134	false
2021-07-27T11:00Z	0.134	false
2021-07-27T10:45Z	0.134	false
2021-07-27T10:30Z	0.135	false
2021-07-27T10:15Z	0.135	false
2021-07-27T10:00Z	0.134	false
2021-07-27T09:45Z	0.134	false
2021-07-27T09:30Z	0.134	false
2021-07-27T09:15Z	0.134	false
2021-07-27T09:00Z	0.133	false
2021-07-27T08:45Z	0.133	false
2021-07-27T08:30Z	0.134	false
2021-07-27T08:15Z	0.134	false
2021-07-27T08:00Z	0.134	false
2021-07-27T07:45Z	0.134	false
2021-07-27T07:30Z	0.134	false
2021-07-27T07:15Z	0.134	false
2021-07-27T07:00Z	0.134	false
2021-07-27T06:45Z	0.134	false
2021-07-27T06:30Z	0.135	false
2021-07-27T06:15Z	0.135	false
2021-07-27T06:00Z	0.134	false
2021-07-27T05:45Z	0.133	false
2021-07-27T05:30Z	0.134	false
2021-07-27T05:15Z	0.134	false
2021-07-27T05:00Z	0.134	false
2021-07-27T04:45Z	0.134	false
2021-07-27T04:30Z	0.134	false
2021-07-27T04:15Z	0.134	false
2021-07-27T04:00Z	0.134	false
2021-07-27T03:45Z	0.134	false
2021-07-27T03:30Z	0.134	false
2021-07-27T03:15Z	0.134	false
2021-07-27T03:00Z	0.134	false
2021-07-27T02:45Z	0.134	false
2021-07-27T02:30Z	0.134	false
2021-07-27T02:15Z	0.134	false
2021-07-27T02:00Z	0.134	false
2021-07-27T01:45Z	0.134	false
2021-07-27T01:30Z	0.134	false
2021-07-27T01:15Z	0.135	false
2021-07-27T01:00Z	0.135	false
2021-07-27T00:45Z	0.135	false
2021-07-27T00:30Z	0.136	false
2021-07-27T00:15Z	0.135	false
2021-07-27T00:00Z	0.135	false
2021-07-26T23:45Z	0.135	false
2021-07-26T23:30Z	0.136	false
2021-07-26T23:15Z	0.136	false
2021-07-26T23:00Z	0.136	false
2021-07-26T22:45Z	0.136	false
2021-07-26T22:30Z	0.136	false
2021-07-26T22:15Z	0.136	false
2021-07-26T22:00Z	0.136	false
2021-07-26T21:45Z	0.136	false
2021-07-26T21:30Z	0.136	false
2021-07-26T21:15Z	0.137	false
2021-07-26T21:00Z	0.137	false
2021-07-26T20:45Z	0.136	false
2021-07-26T20:30Z	0.136	false
2021-07-26T20:15Z	0.136	false
2021-07-26T20:00Z	0.136	false
2021-07-26T19:45Z	0.136	false
2021-07-26T19:30Z	0.136	false
2021-07-26T19:15Z	0.137	false
2021-07-26T19:00Z	0.137	false
2021-07-26T18:45Z	0.137	false
2021-07-26T18:30Z	0.138	false
2021-07-26T18:15Z	0.138	false
2021-07-26T18:00Z	0.138	false
2021-07-26T17:45Z	0.138	false
2021-07-26T17:30Z	0.138	false
2021-07-26T17:15Z	0.138	false
2021-07-26T17:00Z	0.138	false
2021-07-26T16:45Z	0.138	false
2021-07-26T16:30Z	0.138	false
2021-07-26T16:15Z	0.138	false
2021-07-26T16:00Z	0.138	false
2021-07-26T15:45Z	0.138	false
2021-07-26T15:30Z	0.138	false
2021-07-26T15:15Z	0.138	false
2021-07-26T15:00Z	0.138	false
2021-07-26T14:45Z	0.137	false
2021-07-26T14:30Z	0.137	false
2021-07-26T14:15Z	0.137	false
2021-07-26T14:00Z	0.137	false
2021-07-26T13:45Z	0.138	false
2021-07-26T13:30Z	0.138	false
2021-07-26T13:15Z	0.138	false
2021-07-26T13:00Z	0.138	false
2021-07-26T12:45Z	0.139	false
2021-07-26T12:30Z	0.139	false
2021-07-26T12:15Z	0.138	false
2021-07-26T12:00Z	0.139	false
2021-07-26T11:45Z	0.139	false
2021-07-26T11:30Z	0.139	false
2021-07-26T11:15Z	0.139	false
2021-07-26T11:00Z	0.139	false
2021-07-26T10:45Z	0.139	false
2021-07-26T10:30Z	0.139	false
2021-07-26T10:15Z	0.14	false
2021-07-26T10:00Z	0.14	false
2021-07-26T09:45Z	0.14	false
2021-07-26T09:30Z	0.14	false
2021-07-26T09:15Z	0.14	false
2021-07-26T09:00Z	0.14	false
2021-07-26T08:45Z	0.14	false
2021-07-26T08:30Z	0.14	false
2021-07-26T08:15Z	0.14	false
2021-07-26T08:00Z	0.14	false
2021-07-26T07:45Z	0.141	false
2021-07-26T07:30Z	0.141	false
2021-07-26T07:15Z	0.141	false
2021-07-26T07:00Z	0.141	false
2021-07-26T06:45Z	0.141	false
2021-07-26T06:30Z	0.142	false
2021-07-26T06:15Z	0.142	false
2021-07-26T06:00Z	0.142	false
2021-07-26T05:45Z	0.142	false
2021-07-26T05:30Z	0.142	false
2021-07-26T05:15Z	0.142	false
2021-07-26T05:00Z	0.143	false
2021-07-26T04:45Z	0.143	false
2021-07-26T04:30Z	0.143	false
2021-07-26T04:15Z	0.143	false
2021-07-26T04:00Z	0.144	false
2021-07-26T03:45Z	0.144	false
2021-07-26T03:30Z	0.144	false
2021-07-26T03:15Z	0.145	false
2021-07-26T03:00Z	0.145	false
2021-07-26T02:45Z	0.146	false
2021-07-26T02:30Z	0.146	false
2021-07-26T02:15Z	0.146	false
2021-07-26T02:00Z	0.147	false
2021-07-26T01:45Z	0.148	false
2021-07-26T01:30Z	0.148	false
2021-07-26T01:15Z	0.149	false
2021-07-26T01:00Z	0.15	false
2021-07-26T00:45Z	0.15	false
2021-07-26T00:30Z	0.151	false
2021-07-26T00:15Z	0.152	false
2021-07-26T00:00Z	0.153	false
2021-07-25T23:45Z	0.154	false
2021-07-25T23:30Z	0.155	false
2021-07-25T23:15Z	0.156	false
2021-07-25T23:00Z	0.157	false
2021-07-25T22:45Z	0.159	false
2021-07-25T22:30Z	0.161	false
2021-07-25T22:15Z	0.162	false
2021-07-25T22:00Z	0.164	false
2021-07-25T21:45Z	0.167	false
2021-07-25T21:30Z	0.171	false
2021-07-25T21:15Z	0.175	false
2021-07-25T21:00Z	0.179	false
2021-07-25T20:45Z	0.187	false
2021-07-25T20:30Z	0.197	false
2021-07-25T20:15Z	0.21	false
2021-07-25T20:00Z	0.226	false
2021-07-25T19:45Z	0.244	false
2021-07-25T19:30Z	0.258	false
2021-07-25T19:15Z	0.272	false
2021-07-25T19:00Z	0.271	false
2021-07-25T18:45Z	0.268	false
2021-07-25T18:30Z	0.268	false
2021-07-25T18:15Z	0.256	false
2021-07-25T18:00Z	0.25	false
2021-07-25T17:45Z	0.223	false
2021-07-25T17:30Z	0.221	false
2021-07-25T17:15Z	0.162	false
2021-07-25T17:00Z	0.139	false
2021-07-25T16:45Z	0.138	false
2021-07-25T16:30Z	0.138	false
2021-07-25T16:15Z	0.138	false
2021-07-25T16:00Z	0.138	false
2021-07-25T15:45Z	0.138	false
2021-07-25T15:30Z	0.138	false
2021-07-25T15:15Z	0.138	false
2021-07-25T15:00Z	0.138	false
2021-07-25T14:45Z	0.138	false
2021-07-25T14:30Z	0.138	false
2021-07-25T14:15Z	0.139	false
2021-07-25T14:00Z	0.139	false
2021-07-25T13:45Z	0.139	false
2021-07-25T13:30Z	0.139	false
2021-07-25T13:15Z	0.138	false
2021-07-25T13:00Z	0.139	false
2021-07-25T12:45Z	0.138	false
2021-07-25T12:30Z	0.139	false
2021-07-25T12:15Z	0.139	false
2021-07-25T12:00Z	0.139	false
2021-07-25T11:45Z	0.139	false
2021-07-25T11:30Z	0.14	false
2021-07-25T11:15Z	0.14	false
2021-07-25T11:00Z	0.14	false
2021-07-25T10:45Z	0.14	false
2021-07-25T10:30Z	0.14	false
2021-07-25T10:15Z	0.14	false
2021-07-25T10:00Z	0.139	false
2021-07-25T09:45Z	0.139	false
2021-07-25T09:30Z	0.138	false
2021-07-25T09:15Z	0.137	false
2021-07-25T09:00Z	0.136	false
2021-07-25T08:45Z	0.136	false
2021-07-25T08:30Z	0.136	false
2021-07-25T08:15Z	0.136	false
2021-07-25T08:00Z	0.136	false
2021-07-25T07:45Z	0.136	false
2021-07-25T07:30Z	0.135	false
2021-07-25T07:15Z	0.135	false
2021-07-25T07:00Z	0.135	false
2021-07-25T06:45Z	0.135	false
2021-07-25T06:30Z	0.135	false
2021-07-25T06:15Z	0.135	false
2021-07-25T06:00Z	0.134	false
2021-07-25T05:45Z	0.134	false
2021-07-25T05:30Z	0.134	false
2021-07-25T05:15Z	0.134	false
2021-07-25T05:00Z	0.134	false
2021-07-25T04:45Z	0.134	false
2021-07-25T04:30Z	0.134	false
2021-07-25T04:15Z	0.134	false
2021-07-25T04:00Z	0.134	false
2021-07-25T03:45Z	0.134	false
2021-07-25T03:30Z	0.134	false
2021-07-25T03:15Z	0.134	false
2021-07-25T03:00Z	0.134	false
2021-07-25T02:45Z	0.134	false
2021-07-25T02:30Z	0.135	false
2021-07-25T02:15Z	0.135	false
2021-07-25T02:00Z	0.135	false
2021-07-25T01:45Z	0.135	false
2021-07-25T01:30Z	0.135	false
2021-07-25T01:15Z	0.135	false
2021-07-25T01:00Z	0.136	false
2021-07-25T00:45Z	0.136	false
2021-07-25T00:30Z	0.136	false
2021-07-25T00:15Z	0.135	false
2021-07-25T00:00Z	0.136	false
2021-07-24T23:45Z	0.136	false
2021-07-24T23:30Z	0.136	false
2021-07-24T23:15Z	0.136	false
2021-07-24T23:00Z	0.136	false
2021-07-24T22:45Z	0.136	false
2021-07-24T22:30Z	0.135	false
2021-07-24T22:15Z	0.135	false
2021-07-24T22:00Z	0.135	false
2021-07-24T21:45Z	0.135	false
2021-07-24T21:30Z	0.135	false
2021-07-24T21:15Z	0.135	false
2021-07-24T21:00Z	0.135	false
2021-07-24T20:45Z	0.135	false
2021-07-24T20:30Z	0.135	false
2021-07-24T20:15Z	0.135	false
2021-07-24T20:00Z	0.135	false
2021-07-24T19:45Z	0.135	false
2021-07-24T19:30Z	0.135	false
2021-07-24T19:15Z	0.134	false
2021-07-24T19:00Z	0.134	false
2021-07-24T18:45Z	0.134	false
2021-07-24T18:30Z	0.134	false
2021-07-24T18:15Z	0.134	false
2021-07-24T18:00Z	0.134	false
2021-07-24T17:45Z	0.134	false
2021-07-24T17:30Z	0.134	false
2021-07-24T17:15Z	0.134	false
2021-07-24T17:00Z	0.134	false
2021-07-24T16:45Z	0.134	false
2021-07-24T16:30Z	0.133	false
2021-07-24T16:15Z	0.133	false
2021-07-24T16:00Z	0.133	false
2021-07-24T15:45Z	0.134	false
2021-07-24T15:30Z	0.133	false
2021-07-24T15:15Z	0.133	false
2021-07-24T15:00Z	0.134	false
2021-07-24T14:45Z	0.134	false
2021-07-24T14:30Z	0.134	false
2021-07-24T14:15Z	0.134	false
2021-07-24T14:00Z	0.134	false
2021-07-24T13:45Z	0.134	false
2021-07-24T13:30Z	0.133	false
2021-07-24T13:15Z	0.134	false
2021-07-24T13:00Z	0.134	false
2021-07-24T12:45Z	0.134	false
2021-07-24T12:30Z	0.134	false
2021-07-24T12:15Z	0.134	false
2021-07-24T12:00Z	0.135	false
2021-07-24T11:45Z	0.134	false
2021-07-24T11:30Z	0.134	false
2021-07-24T11:15Z	0.135	false
2021-07-24T11:00Z	0.135	false
2021-07-24T10:45Z	0.135	false
2021-07-24T10:30Z	0.135	false
2021-07-24T10:15Z	0.136	false
2021-07-24T10:00Z	0.136	false
2021-07-24T09:45Z	0.136	false
2021-07-24T09:30Z	0.136	false
2021-07-24T09:15Z	0.137	false
2021-07-24T09:00Z	0.137	false

Forecast data

Key information

• Station name: Howletts Lane, Ruislip (TEMP)
• Station ID: 9307
• River name: Cannon Brook
• Typical range: 0.02m to 0.82m
• Highest level on record: 1.05m on 15 October 2018
• Site datum: 40.98mAOD (what does this mean?)

How are river levels measured?

The Environment agency uses a network of monitoring stations across the country. Each one has its own datum - a height in metres fixed relative to mean sea level. This height is expressed as metres above ordnance datum (mAOD). The river levels we provide for each monitoring station are all relative to its site datum.

If we didn't do this, we'd show some very high measurements, which could cause confusion. By using a local site datum, the river levels are easier to understand, especially by users familiar with the data from a particular monitoring station.

A river's height above ordnance datum can be seen by adding the site datum to the river level.

How often are river levels measured?

We use measuring stations like this one to collect water level data, usually once or twice a day. We collect data more frequently when there's a greater risk of flooding. That's why the graph might show a short time lag since the last measurement.

How might river levels affect flood risk?

Typical range

This is the usual range of river levels at this station, based on historical data.

Above typical

This means that flooding is possible because river levels at this station are currently higher than usual.
Many factors can influence the possibility of flooding - river levels are only one indicator. Always check if there's a flood warning in place at a particular location.

Below typical

This means that river levels at this station are currently lower than usual.
Drought or water management measures may be in place. Please check for the latest information on water resources and restrictions in your area.

• View nearby measuring stations

• View the flood information service for England
• Check the long term flood risk for an area in England.

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