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⤴Unusual rise — FloodRadar+Top 1% rise rate for this gauge.
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Drag the line on the chart, or type a value:mASD
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You'll be notified when this gauge is rising more than 0.10 mASD/hr — a sign of rapidly increasing water levels.
You'll be notified when a new storm-overflow (sewage) discharge starts within ~3 km of this gauge, based on the water companies' near-real-time feeds.
Get notified when recent rainfall near this gauge crosses its learnt rise trigger — an early "watch"
signal, typically hours before a rise. Experimental; not an official flood warning.
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EA/SEPA data and are best-efforts. Terms
Current Level
0.276 mASD
▬ Steady
24h Max
0.284 mASD
24h Min
0.275 mASD
Typical Range
0.31 - 0.90
mASD
Highest Recorded
1.98 mASD
EA official record
1.57 in our data (since Jan 1991)
Current level is 14% of this
Current Flow
Loading...
🚽Sewage overflows nearby
Recent Water Levels
🌍 floodradar.co.uk
1 day
Prediction V2
Prediction Eris
Nimbus beta
Experimental model fusing soil moisture, river flow, groundwater and catchment
character. Shown with its calibrated 10–90% confidence band. Under evaluation —
not yet promoted, so treat as a second opinion.
River Flow
90 days
Daily mean discharge (m³/s) with the daily min–max band, from the EA Hydrology API. Flow is the volume of water passing the gauge — often a more direct flood signal than level.
Long Term
🌍 floodradar.co.uk
—
Consecutive rainy days0 → 10+
Days Above Normal
This year vs 5-year monthly range
Recent Readings
Falling · -0.3 cm over 6h
24 Aug 00:00▲ +0.1 cm0.276 mASD
23 Aug 23:45▼ -0.1 cm0.275 mASD
23 Aug 23:30▬ steady0.276 mASD
23 Aug 23:15▬ steady0.276 mASD
23 Aug 23:00▼ -0.1 cm0.276 mASD
23 Aug 22:45▲ +0.1 cm0.277 mASD
23 Aug 21:30▲ +0.1 cm0.276 mASD
23 Aug 21:15▬ steady0.275 mASD
23 Aug 21:00▬ steady0.275 mASD
23 Aug 20:45▬ steady0.275 mASD
23 Aug 20:30▬ steady0.275 mASD
23 Aug 20:15▼ -0.1 cm0.275 mASD
23 Aug 20:00▬ steady0.276 mASD
23 Aug 19:45▼ -0.1 cm0.276 mASD
23 Aug 19:30▲ +0.1 cm0.277 mASD
23 Aug 19:15▼ -0.1 cm0.276 mASD
23 Aug 19:00▬ steady0.277 mASD
23 Aug 18:45▬ steady0.277 mASD
23 Aug 18:30▼ -0.2 cm0.277 mASD
23 Aug 18:150.279 mASD
Rainfall & Weather
Loading rainfall and weather data...
Flood history near this gauge
Official Environment Agency warnings issued since 2013 for the 8 flood
areas linked to this gauge (nearest 0.2 km away).
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 Addlestone flood history.
Geographic coordinates may reflect the access point for the gauge, and not the precise location in the watercourse that it is taking readings from.
Catchment Character
🌊 Urban & flashyHeavily built-up — rain runs off hard surfaces fast, so levels can spike within hours of heavy rain.
Your catchment is all the land that drains rainfall into the river above this gauge. Its character — how
steep, wet, wooded, urban or chalky that land is — decides how fast rain here turns into a rising river. A steep, bare or clay
catchment is “flashy” (rises and falls quickly, floods easily); a flat, chalk or well-wooded one is
slow and steady. The tiles below put numbers to that; the flow-duration curve reads left-to-right
from the river’s typical high flows (Q5) down to its low flows (Q95) — a steep curve means a flashy river.
The physical character of the land that drains to this gauge, and how it shapes its flood response — from the National River Flow Archive (UKCEH).
Baseflow Index
0.57
mixed response
Avg Annual Rainfall
700 mm/yr
1991–2020 · +2% since 1941–70
Urban Extent
15%
heavily urbanised
Highest Recorded Flow
9.90 m³/s
7 Nov 2000
Flow-Duration Curve
Daily flow (m³/s) exceeded each % of the time — a steep curve is flashy, a flat one is steady. Q5 high · Q50 median · Q95 low.
The geology is largely impermeable Bagshot Beds. Very mixed land use with woodland and heath plus significant urban development.
The station
Cross-path time-of-flight ultrasonic station installed in 2012/13. After becoming ultrasonic, a bund was added to promote head level at low flows. Prior to ultrasonic, this was a velocity area station - low level sharp-crested weir (rather insensitive with poor approach conditions).
How it measures flow
Control passes to road bridge at medium/high flows. Some confirmatory gaugings up to approx. 10 cumecs. Possible bypassing into R. Wey system (via canal) at very high flows. Rating change in Oct 1993 (earlier data may need reprocessing).
How this gauging station is built and how long it has measured (NRFA / UKCEH).
Gauge type
Ultrasonic
Operating since
1991
Station datum
10.9 mAOD
Flow record
1991–2024 · 33 yrs · 94% complete
Hydrometric area
39
Measured by
Environment Agency
Nearby Groundwater
Soil Moisture
Possible storm-overflow correlation
🚽 Storm overflows on this river
Frequently asked questions
Is the Addlestone Bourne at Addlestone flooding today?
The current level is 0.28m, which is below the typical range. Flooding is very unlikely at this level.
Is the river level rising or falling at Addlestone?
Based on the most recent readings, the level is currently steady. The chart above shows the last 7 days of measurements, updated roughly every 15 minutes.
What is a normal level for the Addlestone Bourne at Addlestone?
The typical range at this station is 0.31m to 0.90m, based on Environment Agency historical data. Levels above 0.90m are higher than usually seen and may indicate a flood risk.
How often is this river level data updated?
Readings are taken by the Environment Agency gauge roughly every 15 minutes and FloodRadar refreshes its data continuously, so the level shown is normally less than an hour old.
Embed this gauge on your website
Free live river-level widget — ideal for parish councils, angling clubs and local sites. Updates automatically.
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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:
