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0.33

Grants Bridge

Addlestone Bourne
Bournes catchment • Chobham • Surrey • ID: 2976TH • Level
(1h ago) • 1 reading/hr • 131 views

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⤴ Unusual rise — FloodRadar+Top 1% rise rate for this gauge.
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Not an emergency service — if in danger call 999. Alerts rely on EA/SEPA/NRW data and are best-efforts. Terms

Current Level
0.332 mASD
▬ Steady
24h Max
0.349 mASD
24h Min
0.332 mASD
Typical Range
0.33 - 1.55
mASD
Highest Recorded
2.50 mASD
EA official record
1.96 in our data (since Jan 1998)
Current level is 13% of this
🚽 Sewage overflows nearby

Recent Water Levels

🌍 floodradar.co.uk
1 day

Recent Readings

Falling · -0.9 cm over 9h
09 Oct 15:00 ▼ -0.8 cm 0.332 mASD
09 Oct 11:00 ▼ -0.1 cm 0.340 mASD
09 Oct 10:45 ▲ +0.1 cm 0.341 mASD
09 Oct 10:30 ▼ -0.1 cm 0.340 mASD
09 Oct 10:15 ▼ -0.2 cm 0.341 mASD
09 Oct 10:00 ▲ +0.1 cm 0.343 mASD
09 Oct 09:45 ▼ -0.2 cm 0.342 mASD
09 Oct 09:30 ▲ +0.2 cm 0.344 mASD
09 Oct 09:15 ▬ steady 0.342 mASD
09 Oct 09:00 ▬ steady 0.342 mASD
09 Oct 08:45 ▲ +0.1 cm 0.342 mASD
09 Oct 08:30 ▲ +0.1 cm 0.341 mASD
09 Oct 08:15 ▼ -0.1 cm 0.340 mASD
09 Oct 08:00 ▲ +0.1 cm 0.341 mASD
09 Oct 07:45 ▬ steady 0.340 mASD
09 Oct 07:30 ▼ -0.2 cm 0.340 mASD
09 Oct 07:15 ▲ +0.1 cm 0.342 mASD
09 Oct 07:00 ▬ steady 0.341 mASD
09 Oct 06:45 ▬ steady 0.341 mASD
09 Oct 06:30 0.341 mASD

Station Details

  • Monitoring Station: Grants Bridge
  • Watercourse: Addlestone Bourne
  • Nearest Town: Chobham
  • County: Surrey
  • Coordinates: 51°20'40"N 0°36'15"W (51.344527, -0.604091)
  • Open in: Google Maps · Apple Maps (opens your maps app)
  • Date Opened: 1 Jan 1997
  • Status: Active
  • Station Type: River level station
Technical details: references, datum, range, flow archive
  • Station Reference: 2976TH
  • RLOI id: 7224 (the EA's check-for-flooding station id)
  • EA Gauge ID: 2976TH-level-stage-i-15_min-mASD
  • Parameter: Level
  • Unit: mASD
  • Typical rise rate: 1 cm/hr (p95 sustained over 90 days)
  • Typical data delay: ~22 min (measured reading→publication lag)
  • Tidal: No
  • Lock / structure: No
  • Catchment Area: Bournes
  • Typical Range: 0.326 – 1.550 mASD
  • EA Cross-check: 0.33 mASD (EA at 9 Oct 15:00)

Geographic coordinates may reflect the access point for the gauge, and not the precise location in the watercourse that it is taking readings from.

Nearby Stations

Gauges connected to this river, and others nearby. A distance “by river” follows the river on the map; any other is in a straight line.

Connected downstream

Same river system, separate branch

Distances by river: OS Open Rivers. Contains OS data © Crown copyright and database rights 2026.

💧 Storm overflows upstream of this gauge

None of the storm overflows FloodRadar holds is traced upstream of this gauge on the mapped river network. That is not the same as none: the map leaves out many small streams and culverts, so an overflow it cannot place may still drain here, and not every company publishes every overflow. Those nearby are listed below.

Nearby, connection not known

Within 6 km in a straight line, but the river map cannot say whether their water passes this gauge.

💧
Thames Water · into Bourne - South · 660 m away in a straight line · no mapped watercourse close enough to be sure
20 spills · 288 hours in 2025
Not discharging now · last
💧
Thames Water · into Hale Bourne · 3.5 km away in a straight line · no mapped watercourse close enough to be sure
17 spills · 136 hours in 2025
Not discharging now · last

These are the water companies' monitor statuses; a spill does not by itself explain a change in the gauge level. River connections and distances are traced on OS Open Rivers (edition 2026-04), which leaves out many small channels. Explore the sewage map →

Contains OS data © Crown copyright and database rights 2026.

Rainfall & Weather

Loading rainfall and weather data...

How often this river runs high

This gauge rarely reaches its typical high of 1.55 m: 0 days since 2017. This year so far: 0 days.

2026 0 days so far
2025 0 days
2024 0 days
2023 0 days
2022 0 days
2021 0 days
2020 0 days
2019 0 days
2018 0 days
2017 0 days

Counted from each day's highest reading. Days with missing or implausible readings are left out.

Flood history near this gauge

Official Environment Agency warnings issued since 2012 for the 13 flood areas linked to this gauge (nearest 1.1 km away).

6flood warnings 105flood alerts

Most recent flood warning: 24 Feb 2025 — Hoe Stream at Woking

Year by year
YearWarningsAlerts
2026 0 6
2025 1 7
2024 2 18
2023 0 10
2022 0 9
2021 0 4
2020 1 5
2019 0 6
2018 0 7
2017 0 5
2016 1 7
2015 0 4
2014 1 9
2013 0 4
2012 0 4

Warnings apply to a whole flood area, not necessarily this exact spot. Years before 2006 aren't covered by the EA's historic record. See also the Chobham flood history.

Flood areas linked to this gauge

Flood warnings and alerts are issued for whole areas. These are the 13 areas linked to this gauge, nearest first.

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Frequently asked questions

Is the Addlestone Bourne at Grants Bridge flooding today?

The current level is 0.33m, which is within the typical range of 0.33 to 1.55m. Flooding is unlikely at this level.

Is the river level rising or falling at Grants Bridge?

Based on the most recent readings, the level is currently steady. The chart above shows the last 12 hours of measurements by default (up to 7 days), updated roughly every 15 minutes.

Why is the level slowly falling?

When little or no rain has fallen for a while, a river level gradually drops as the water stored in the ground and soil drains away with nothing to replace it. This is called baseflow recession and is normal in dry spells. Only about 7.7mm of rain has fallen nearby in the last 7 days, so the flow is being sustained mainly by groundwater. A gentle decline like this is expected and is not a sign of a problem — downstream gauges often recede a little faster than headwaters further upstream, and levels recover once rain returns.

What is a normal level for the Addlestone Bourne at Grants Bridge?

The typical range at this station is 0.33m to 1.55m, based on Environment Agency historical data. Levels above 1.55m are higher than usually seen and may indicate a flood risk.

How often is this river level data updated?

Readings are supplied by the Environment Agency gauge. FloodRadar checks for updates roughly every 15 minutes; the timestamp above shows how recent the latest available reading is.

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📮 Flood risk by postcode near this gauge

Postcodes within 5 km with properties in the Environment Agency’s rivers-and-sea flood-risk bands:

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🏠 Buying or renting around here? Get the Property Flood-Risk Report for any English postcode — official risk band, recorded floods, warning history, river behaviour and nearby storm overflows. £19 one-off. Learn more →