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

Check for flood warnings in this area

Latest recorded level 0.11m at 9:45am Sunday 29 March 2020.

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
• Show highest recorded level

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Observed data

DateTime	Value	Error
2020-03-29T08:45Z	0.113	false
2020-03-29T08:30Z	0.114	false
2020-03-29T08:15Z	0.113	false
2020-03-29T08:00Z	0.113	false
2020-03-29T07:45Z	0.113	false
2020-03-29T07:30Z	0.113	false
2020-03-29T07:15Z	0.113	false
2020-03-29T07:00Z	0.113	false
2020-03-29T06:45Z	0.113	false
2020-03-29T06:30Z	0.113	false
2020-03-29T06:15Z	0.113	false
2020-03-29T06:00Z	0.113	false
2020-03-29T05:45Z	0.113	false
2020-03-29T05:30Z	0.114	false
2020-03-29T05:15Z	0.113	false
2020-03-29T05:00Z	0.113	false
2020-03-29T04:45Z	0.113	false
2020-03-29T04:30Z	0.113	false
2020-03-29T04:15Z	0.113	false
2020-03-29T04:00Z	0.113	false
2020-03-29T03:45Z	0.113	false
2020-03-29T03:30Z	0.113	false
2020-03-29T03:15Z	0.114	false
2020-03-29T03:00Z	0.113	false
2020-03-29T02:45Z	0.113	false
2020-03-29T02:30Z	0.113	false
2020-03-29T02:15Z	0.113	false
2020-03-29T02:00Z	0.114	false
2020-03-29T01:45Z	0.114	false
2020-03-29T01:30Z	0.113	false
2020-03-29T01:15Z	0.114	false
2020-03-29T01:00Z	0.114	false
2020-03-29T00:45Z	0.114	false
2020-03-29T00:30Z	0.114	false
2020-03-29T00:15Z	0.114	false
2020-03-29T00:00Z	0.114	false
2020-03-28T23:45Z	0.114	false
2020-03-28T23:30Z	0.114	false
2020-03-28T23:15Z	0.114	false
2020-03-28T23:00Z	0.114	false
2020-03-28T22:45Z	0.114	false
2020-03-28T22:30Z	0.114	false
2020-03-28T22:15Z	0.114	false
2020-03-28T22:00Z	0.114	false
2020-03-28T21:45Z	0.114	false
2020-03-28T21:30Z	0.114	false
2020-03-28T21:15Z	0.114	false
2020-03-28T21:00Z	0.114	false
2020-03-28T20:45Z	0.113	false
2020-03-28T20:30Z	0.113	false
2020-03-28T20:15Z	0.113	false
2020-03-28T20:00Z	0.113	false
2020-03-28T19:45Z	0.113	false
2020-03-28T19:30Z	0.113	false
2020-03-28T19:15Z	0.113	false
2020-03-28T19:00Z	0.113	false
2020-03-28T18:45Z	0.114	false
2020-03-28T18:30Z	0.114	false
2020-03-28T18:15Z	0.114	false
2020-03-28T18:00Z	0.114	false
2020-03-28T17:45Z	0.114	false
2020-03-28T17:30Z	0.114	false
2020-03-28T17:15Z	0.114	false
2020-03-28T17:00Z	0.114	false
2020-03-28T16:45Z	0.115	false
2020-03-28T16:30Z	0.114	false
2020-03-28T16:15Z	0.114	false
2020-03-28T16:00Z	0.113	false
2020-03-28T15:45Z	0.114	false
2020-03-28T15:30Z	0.115	false
2020-03-28T15:15Z	0.115	false
2020-03-28T15:00Z	0.115	false
2020-03-28T14:45Z	0.114	false
2020-03-28T14:30Z	0.114	false
2020-03-28T14:15Z	0.115	false
2020-03-28T14:00Z	0.114	false
2020-03-28T13:45Z	0.115	false
2020-03-28T13:30Z	0.115	false
2020-03-28T13:15Z	0.115	false
2020-03-28T13:00Z	0.115	false
2020-03-28T12:45Z	0.115	false
2020-03-28T12:30Z	0.115	false
2020-03-28T12:15Z	0.115	false
2020-03-28T12:00Z	0.115	false
2020-03-28T11:45Z	0.114	false
2020-03-28T11:30Z	0.115	false
2020-03-28T11:15Z	0.115	false
2020-03-28T11:00Z	0.114	false
2020-03-28T10:45Z	0.115	false
2020-03-28T10:30Z	0.115	false
2020-03-28T10:15Z	0.114	false
2020-03-28T10:00Z	0.114	false
2020-03-28T09:45Z	0.114	false
2020-03-28T09:30Z	0.113	false
2020-03-28T09:15Z	0.114	false
2020-03-28T09:00Z	0.114	false
2020-03-28T08:45Z	0.114	false
2020-03-28T08:30Z	0.113	false
2020-03-28T08:15Z	0.113	false
2020-03-28T08:00Z	0.113	false
2020-03-28T07:45Z	0.114	false
2020-03-28T07:30Z	0.113	false
2020-03-28T07:15Z	0.114	false
2020-03-28T07:00Z	0.113	false
2020-03-28T06:45Z	0.114	false
2020-03-28T06:30Z	0.113	false
2020-03-28T06:15Z	0.113	false
2020-03-28T06:00Z	0.113	false
2020-03-28T05:45Z	0.113	false
2020-03-28T05:30Z	0.113	false
2020-03-28T05:15Z	0.113	false
2020-03-28T05:00Z	0.114	false
2020-03-28T04:45Z	0.113	false
2020-03-28T04:30Z	0.113	false
2020-03-28T04:15Z	0.113	false
2020-03-28T04:00Z	0.114	false
2020-03-28T03:45Z	0.114	false
2020-03-28T03:30Z	0.114	false
2020-03-28T03:15Z	0.113	false
2020-03-28T03:00Z	0.114	false
2020-03-28T02:45Z	0.113	false
2020-03-28T02:30Z	0.113	false
2020-03-28T02:15Z	0.113	false
2020-03-28T02:00Z	0.114	false
2020-03-28T01:45Z	0.114	false
2020-03-28T01:30Z	0.114	false
2020-03-28T01:15Z	0.114	false
2020-03-28T01:00Z	0.114	false
2020-03-28T00:45Z	0.114	false
2020-03-28T00:30Z	0.114	false
2020-03-28T00:15Z	0.114	false
2020-03-28T00:00Z	0.114	false
2020-03-27T23:45Z	0.114	false
2020-03-27T23:30Z	0.114	false
2020-03-27T23:15Z	0.114	false
2020-03-27T23:00Z	0.114	false
2020-03-27T22:45Z	0.114	false
2020-03-27T22:30Z	0.114	false
2020-03-27T22:15Z	0.114	false
2020-03-27T22:00Z	0.114	false
2020-03-27T21:45Z	0.114	false
2020-03-27T21:30Z	0.114	false
2020-03-27T21:15Z	0.114	false
2020-03-27T21:00Z	0.114	false
2020-03-27T20:45Z	0.114	false
2020-03-27T20:30Z	0.114	false
2020-03-27T20:15Z	0.114	false
2020-03-27T20:00Z	0.114	false
2020-03-27T19:45Z	0.114	false
2020-03-27T19:30Z	0.114	false
2020-03-27T19:15Z	0.115	false
2020-03-27T19:00Z	0.115	false
2020-03-27T18:45Z	0.115	false
2020-03-27T18:30Z	0.115	false
2020-03-27T18:15Z	0.115	false
2020-03-27T18:00Z	0.115	false
2020-03-27T17:45Z	0.115	false
2020-03-27T17:30Z	0.115	false
2020-03-27T17:15Z	0.116	false
2020-03-27T17:00Z	0.116	false
2020-03-27T16:45Z	0.116	false
2020-03-27T16:30Z	0.117	false
2020-03-27T16:15Z	0.116	false
2020-03-27T16:00Z	0.116	false
2020-03-27T15:45Z	0.116	false
2020-03-27T15:30Z	0.117	false
2020-03-27T15:15Z	0.116	false
2020-03-27T15:00Z	0.117	false
2020-03-27T14:45Z	0.117	false
2020-03-27T14:30Z	0.117	false
2020-03-27T14:15Z	0.116	false
2020-03-27T14:00Z	0.117	false
2020-03-27T13:45Z	0.117	false
2020-03-27T13:30Z	0.117	false
2020-03-27T13:15Z	0.117	false
2020-03-27T13:00Z	0.117	false
2020-03-27T12:45Z	0.117	false
2020-03-27T12:30Z	0.118	false
2020-03-27T12:15Z	0.117	false
2020-03-27T12:00Z	0.116	false
2020-03-27T11:45Z	0.116	false
2020-03-27T11:30Z	0.116	false
2020-03-27T11:15Z	0.116	false
2020-03-27T11:00Z	0.115	false
2020-03-27T10:45Z	0.116	false
2020-03-27T10:30Z	0.115	false
2020-03-27T10:15Z	0.115	false
2020-03-27T10:00Z	0.115	false
2020-03-27T09:45Z	0.114	false
2020-03-27T09:30Z	0.114	false
2020-03-27T09:15Z	0.114	false
2020-03-27T09:00Z	0.114	false
2020-03-27T08:45Z	0.114	false
2020-03-27T08:30Z	0.114	false
2020-03-27T08:15Z	0.114	false
2020-03-27T08:00Z	0.114	false
2020-03-27T07:45Z	0.114	false
2020-03-27T07:30Z	0.114	false
2020-03-27T07:15Z	0.114	false
2020-03-27T07:00Z	0.114	false
2020-03-27T06:45Z	0.114	false
2020-03-27T06:30Z	0.114	false
2020-03-27T06:15Z	0.114	false
2020-03-27T06:00Z	0.114	false
2020-03-27T05:45Z	0.114	false
2020-03-27T05:30Z	0.114	false
2020-03-27T05:15Z	0.114	false
2020-03-27T05:00Z	0.114	false
2020-03-27T04:45Z	0.114	false
2020-03-27T04:30Z	0.114	false
2020-03-27T04:15Z	0.114	false
2020-03-27T04:00Z	0.114	false
2020-03-27T03:45Z	0.114	false
2020-03-27T03:30Z	0.114	false
2020-03-27T03:15Z	0.114	false
2020-03-27T03:00Z	0.114	false
2020-03-27T02:45Z	0.114	false
2020-03-27T02:30Z	0.114	false
2020-03-27T02:15Z	0.114	false
2020-03-27T02:00Z	0.114	false
2020-03-27T01:45Z	0.114	false
2020-03-27T01:30Z	0.114	false
2020-03-27T01:15Z	0.114	false
2020-03-27T01:00Z	0.114	false
2020-03-27T00:45Z	0.114	false
2020-03-27T00:30Z	0.114	false
2020-03-27T00:15Z	0.114	false
2020-03-27T00:00Z	0.114	false
2020-03-26T23:45Z	0.114	false
2020-03-26T23:30Z	0.114	false
2020-03-26T23:15Z	0.114	false
2020-03-26T23:00Z	0.114	false
2020-03-26T22:45Z	0.114	false
2020-03-26T22:30Z	0.114	false
2020-03-26T22:15Z	0.114	false
2020-03-26T22:00Z	0.114	false
2020-03-26T21:45Z	0.114	false
2020-03-26T21:30Z	0.114	false
2020-03-26T21:15Z	0.114	false
2020-03-26T21:00Z	0.114	false
2020-03-26T20:45Z	0.114	false
2020-03-26T20:30Z	0.115	false
2020-03-26T20:15Z	0.115	false
2020-03-26T20:00Z	0.115	false
2020-03-26T19:45Z	0.115	false
2020-03-26T19:30Z	0.115	false
2020-03-26T19:15Z	0.115	false
2020-03-26T19:00Z	0.115	false
2020-03-26T18:45Z	0.116	false
2020-03-26T18:30Z	0.116	false
2020-03-26T18:15Z	0.116	false
2020-03-26T18:00Z	0.116	false
2020-03-26T17:45Z	0.116	false
2020-03-26T17:30Z	0.117	false
2020-03-26T17:15Z	0.117	false
2020-03-26T17:00Z	0.117	false
2020-03-26T16:45Z	0.117	false
2020-03-26T16:30Z	0.117	false
2020-03-26T16:15Z	0.117	false
2020-03-26T16:00Z	0.117	false
2020-03-26T15:45Z	0.117	false
2020-03-26T15:30Z	0.117	false
2020-03-26T15:15Z	0.117	false
2020-03-26T15:00Z	0.117	false
2020-03-26T14:45Z	0.117	false
2020-03-26T14:30Z	0.117	false
2020-03-26T14:15Z	0.117	false
2020-03-26T14:00Z	0.117	false
2020-03-26T13:45Z	0.117	false
2020-03-26T13:30Z	0.117	false
2020-03-26T13:15Z	0.118	false
2020-03-26T13:00Z	0.117	false
2020-03-26T12:45Z	0.118	false
2020-03-26T12:30Z	0.118	false
2020-03-26T12:15Z	0.118	false
2020-03-26T12:00Z	0.118	false
2020-03-26T11:45Z	0.117	false
2020-03-26T11:30Z	0.118	false
2020-03-26T11:15Z	0.118	false
2020-03-26T11:00Z	0.118	false
2020-03-26T10:45Z	0.118	false
2020-03-26T10:30Z	0.117	false
2020-03-26T10:15Z	0.117	false
2020-03-26T10:00Z	0.117	false
2020-03-26T09:45Z	0.117	false
2020-03-26T09:30Z	0.117	false
2020-03-26T09:15Z	0.117	false
2020-03-26T09:00Z	0.117	false
2020-03-26T08:45Z	0.117	false
2020-03-26T08:30Z	0.118	false
2020-03-26T08:15Z	0.119	false
2020-03-26T08:00Z	0.119	false
2020-03-26T07:45Z	0.12	false
2020-03-26T07:30Z	0.12	false
2020-03-26T07:15Z	0.121	false
2020-03-26T07:00Z	0.121	false
2020-03-26T06:45Z	0.122	false
2020-03-26T06:30Z	0.122	false
2020-03-26T06:15Z	0.123	false
2020-03-26T06:00Z	0.123	false
2020-03-26T05:45Z	0.124	false
2020-03-26T05:30Z	0.125	false
2020-03-26T05:15Z	0.125	false
2020-03-26T05:00Z	0.127	false
2020-03-26T04:45Z	0.128	false
2020-03-26T04:30Z	0.129	false
2020-03-26T04:15Z	0.13	false
2020-03-26T04:00Z	0.132	false
2020-03-26T03:45Z	0.134	false
2020-03-26T03:30Z	0.135	false
2020-03-26T03:15Z	0.136	false
2020-03-26T03:00Z	0.138	false
2020-03-26T02:45Z	0.139	false
2020-03-26T02:30Z	0.141	false
2020-03-26T02:15Z	0.144	false
2020-03-26T02:00Z	0.15	false
2020-03-26T01:45Z	0.159	false
2020-03-26T01:30Z	0.173	false
2020-03-26T01:15Z	0.199	false
2020-03-26T01:00Z	0.265	false
2020-03-26T00:45Z	0.386	false
2020-03-26T00:30Z	0.399	false
2020-03-26T00:15Z	0.399	false
2020-03-26T00:00Z	0.4	false
2020-03-25T23:45Z	0.399	false
2020-03-25T23:30Z	0.399	false
2020-03-25T23:15Z	0.399	false
2020-03-25T23:00Z	0.399	false
2020-03-25T22:45Z	0.399	false
2020-03-25T22:30Z	0.399	false
2020-03-25T22:15Z	0.399	false
2020-03-25T22:00Z	0.399	false
2020-03-25T21:45Z	0.398	false
2020-03-25T21:30Z	0.399	false
2020-03-25T21:15Z	0.401	false
2020-03-25T21:00Z	0.4	false
2020-03-25T20:45Z	0.4	false
2020-03-25T20:30Z	0.401	false
2020-03-25T20:15Z	0.4	false
2020-03-25T20:00Z	0.4	false
2020-03-25T19:45Z	0.4	false
2020-03-25T19:30Z	0.4	false
2020-03-25T19:15Z	0.401	false
2020-03-25T19:00Z	0.401	false
2020-03-25T18:45Z	0.401	false
2020-03-25T18:30Z	0.401	false
2020-03-25T18:15Z	0.401	false
2020-03-25T18:00Z	0.402	false
2020-03-25T17:45Z	0.402	false
2020-03-25T17:30Z	0.403	false
2020-03-25T17:15Z	0.401	false
2020-03-25T17:00Z	0.402	false
2020-03-25T16:45Z	0.401	false
2020-03-25T16:30Z	0.401	false
2020-03-25T16:15Z	0.401	false
2020-03-25T16:00Z	0.401	false
2020-03-25T15:45Z	0.402	false
2020-03-25T15:30Z	0.402	false
2020-03-25T15:15Z	0.401	false
2020-03-25T15:00Z	0.401	false
2020-03-25T14:45Z	0.401	false
2020-03-25T14:30Z	0.402	false
2020-03-25T14:15Z	0.402	false
2020-03-25T14:00Z	0.402	false
2020-03-25T13:45Z	0.401	false
2020-03-25T13:30Z	0.402	false
2020-03-25T13:15Z	0.401	false
2020-03-25T13:00Z	0.401	false
2020-03-25T12:45Z	0.401	false
2020-03-25T12:30Z	0.401	false
2020-03-25T12:15Z	0.402	false
2020-03-25T12:00Z	0.4	false
2020-03-25T11:45Z	0.4	false
2020-03-25T11:30Z	0.4	false
2020-03-25T11:15Z	0.399	false
2020-03-25T11:00Z	0.4	false
2020-03-25T10:45Z	0.4	false
2020-03-25T10:30Z	0.401	false
2020-03-25T10:15Z	0.398	false
2020-03-25T10:00Z	0.399	false
2020-03-25T09:45Z	0.399	false
2020-03-25T09:30Z	0.399	false
2020-03-25T09:15Z	0.399	false
2020-03-25T09:00Z	0.399	false
2020-03-25T08:45Z	0.399	false
2020-03-25T08:30Z	0.398	false
2020-03-25T08:15Z	0.393	false
2020-03-25T08:00Z	0.393	false
2020-03-25T07:45Z	0.373	false
2020-03-25T07:30Z	0.26	false
2020-03-25T07:15Z	0.12	false
2020-03-25T07:00Z	0.121	false
2020-03-25T06:45Z	0.121	false
2020-03-25T06:30Z	0.122	false
2020-03-25T06:15Z	0.123	false
2020-03-25T06:00Z	0.124	false
2020-03-25T05:45Z	0.124	false
2020-03-25T05:30Z	0.125	false
2020-03-25T05:15Z	0.127	false
2020-03-25T05:00Z	0.128	false
2020-03-25T04:45Z	0.13	false
2020-03-25T04:30Z	0.132	false
2020-03-25T04:15Z	0.133	false
2020-03-25T04:00Z	0.135	false
2020-03-25T03:45Z	0.136	false
2020-03-25T03:30Z	0.138	false
2020-03-25T03:15Z	0.14	false
2020-03-25T03:00Z	0.144	false
2020-03-25T02:45Z	0.151	false
2020-03-25T02:30Z	0.161	false
2020-03-25T02:15Z	0.178	false
2020-03-25T02:00Z	0.211	false
2020-03-25T01:45Z	0.304	false
2020-03-25T01:30Z	0.4	false
2020-03-25T01:15Z	0.4	false
2020-03-25T01:00Z	0.401	false
2020-03-25T00:45Z	0.401	false
2020-03-25T00:30Z	0.4	false
2020-03-25T00:15Z	0.402	false
2020-03-25T00:00Z	0.401	false
2020-03-24T23:45Z	0.401	false
2020-03-24T23:30Z	0.401	false
2020-03-24T23:15Z	0.402	false
2020-03-24T23:00Z	0.401	false
2020-03-24T22:45Z	0.401	false
2020-03-24T22:30Z	0.401	false
2020-03-24T22:15Z	0.4	false
2020-03-24T22:00Z	0.401	false
2020-03-24T21:45Z	0.401	false
2020-03-24T21:30Z	0.401	false
2020-03-24T21:15Z	0.401	false
2020-03-24T21:00Z	0.401	false
2020-03-24T20:45Z	0.401	false
2020-03-24T20:30Z	0.402	false
2020-03-24T20:15Z	0.401	false
2020-03-24T20:00Z	0.402	false
2020-03-24T19:45Z	0.402	false
2020-03-24T19:30Z	0.402	false
2020-03-24T19:15Z	0.402	false
2020-03-24T19:00Z	0.403	false
2020-03-24T18:45Z	0.401	false
2020-03-24T18:30Z	0.402	false
2020-03-24T18:15Z	0.402	false
2020-03-24T18:00Z	0.401	false
2020-03-24T17:45Z	0.402	false
2020-03-24T17:30Z	0.402	false
2020-03-24T17:15Z	0.402	false
2020-03-24T17:00Z	0.401	false
2020-03-24T16:45Z	0.402	false
2020-03-24T16:30Z	0.402	false
2020-03-24T16:15Z	0.402	false
2020-03-24T16:00Z	0.402	false
2020-03-24T15:45Z	0.401	false
2020-03-24T15:30Z	0.4	false
2020-03-24T15:15Z	0.402	false
2020-03-24T15:00Z	0.402	false
2020-03-24T14:45Z	0.402	false
2020-03-24T14:30Z	0.403	false
2020-03-24T14:15Z	0.403	false
2020-03-24T14:00Z	0.402	false
2020-03-24T13:45Z	0.403	false
2020-03-24T13:30Z	0.402	false
2020-03-24T13:15Z	0.402	false
2020-03-24T13:00Z	0.402	false
2020-03-24T12:45Z	0.402	false
2020-03-24T12:30Z	0.401	false
2020-03-24T12:15Z	0.401	false
2020-03-24T12:00Z	0.403	false
2020-03-24T11:45Z	0.403	false
2020-03-24T11:30Z	0.402	false
2020-03-24T11:15Z	0.402	false
2020-03-24T11:00Z	0.402	false
2020-03-24T10:45Z	0.403	false
2020-03-24T10:30Z	0.401	false
2020-03-24T10:15Z	0.403	false
2020-03-24T10:00Z	0.401	false
2020-03-24T09:45Z	0.401	false
2020-03-24T09:30Z	0.402	false
2020-03-24T09:15Z	0.401	false
2020-03-24T09:00Z	0.399	false
2020-03-24T08:45Z	0.398	false
2020-03-24T08:30Z	0.385	false
2020-03-24T08:15Z	0.32	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
• View your property's long term risk of flooding

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