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⤴Unusual rise — FloodRadar+Top 1% rise rate for this gauge.
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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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Current Level
0.232 mASD
▬ Steady
24h Max
0.275 mASD
24h Min
0.228 mASD
Typical Range
0.17 - 1.55
mASD
Highest Recorded
2.45 mASD
17 Oct 1998
Since Jan 1971
Current level is 9% of this
🚽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
Steady over 6h
24 Aug 00:15▬ steady0.232 mASD
24 Aug 00:00▲ +0.1 cm0.232 mASD
23 Aug 23:45▬ steady0.231 mASD
23 Aug 23:30▼ -0.1 cm0.231 mASD
23 Aug 23:15▬ steady0.232 mASD
23 Aug 23:00▬ steady0.232 mASD
23 Aug 22:45▼ -0.2 cm0.232 mASD
23 Aug 21:30▬ steady0.234 mASD
23 Aug 21:15▲ +0.1 cm0.234 mASD
23 Aug 21:00▬ steady0.233 mASD
23 Aug 20:45▬ steady0.233 mASD
23 Aug 20:30▬ steady0.233 mASD
23 Aug 20:15▬ steady0.233 mASD
23 Aug 20:00▬ steady0.233 mASD
23 Aug 19:45▬ steady0.233 mASD
23 Aug 19:30▲ +0.1 cm0.233 mASD
23 Aug 19:15▬ steady0.232 mASD
23 Aug 19:00▬ steady0.232 mASD
23 Aug 18:45▲ +0.1 cm0.232 mASD
23 Aug 18:300.231 mASD
Rainfall & Weather
Loading rainfall and weather data...
Flood history near this gauge
Official Environment Agency warnings issued since 2014 for the 3 flood
areas linked to this gauge (nearest 1.3 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 Hadlow 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
🌊 Mixed responseA balance of quick runoff and slower groundwater baseflow.
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
0.63
mixed response
Avg Annual Rainfall
755 mm/yr
1991–2020 · +3% since 1941–70
Urban Extent
3.6%
partly urbanised
Highest Recorded Flow
9.41 m³/s
1 Aug 1991
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.
Electromagnetic gauge installed July 2002, located in a formalised flume structure. Flow record often incomplete. Capable of flashy response. In July 2024 the EM was retired and replaced with a Cross Correlation gauge within EM section.
More detail
The catchment
A largely baseflow dominated regime, the River Bourne rises on Gault Clay below the scarp of the North Downs, forming a tributary to the River Medway. The river flows south cutting through Ragstone Ridge, an outcrop of Lower Greensand, before entering the Vale of Kent. It is fed by springs from the Lower Greensand but runoff is predominantly generated from the Weald Clays of the Vale of Kent. Area of the catchment naturally impervious and pervious (half-and-half), including Upper, Middle & Lower Chalk, Folkestone Beds, Atherfield Clay, Gault Clay, Sandgate Beds, Hythe Beds, Weald Clay. A mainly rural catchment, excluding Borough Green which occupies <1% of the total catchment area. Remainder is grazing and woodland with a substantial acreage devoted to orchards.
The station
Electromagnetic gauge installed July 2002, located in a formalised flume structure, situated on a 0.2 km straight reach of the River Bourne approx 100m d/s of the A26 bridge at Hadlow. At the end of the measurement reach the river passes under a farm bridge. Originally a trapezoidal (long throated) critical depth flume, with stated capacity 8.5m3/s, though drowned at high flows - variable modular limit and constant dredging needed downstream. Removed from peak flows dataset in February 2018 (WINFAP Files v6).
How it measures flow
Electromagnetic flume has significantly bigger cross-section (and thus flow capacity) than previous trapezoidal (long throated) flume. Long throated flume rating based on hydraulic calculations. Rated to bankfull and hydraulic modelling beyond. No high-flow or out-of-bank gaugings to confirm rating. Cross correlation gauge appears to perform better than EM for low-medium flows when compared to flow gaugings. However, overwide section is causing erratic velocities through measuring section at higher flows. Currently flows above 2.5m3/s (1mASD) have the most uncertainty. Continous work to improve the gauges performance is ongoing.
Flow regime
Capable of flashy response; rapid runoff from the Weald Clay. Some artificial regulation from a mill half a mile u/s, this effect causes differences of up to 3 cumecs. Significant spray irrigation. Runoff increased by effluent returns. Very substantial baseflow contribution but capable of flashy response. Some artificial regulation from mill upstream. Significant spray irrigation. Public water supply abstractions from groundwater.
The flow record
Flow estimates for both the original flume and EM gauge are poor, with a step change between the two records. 1968 peak flow estimated at 57 cumecs on basis of wrack marks.
How this gauging station is built and how long it has measured (NRFA / UKCEH).
Gauge type
Electromagnetic
Operating since
1959
Station datum
24.0 mAOD
Flow record
1959–2024 · 65 yrs · 86% complete
Hydrometric area
40
Measured by
Environment Agency
Nearby Groundwater
Soil Moisture
Possible storm-overflow correlation
🚽 Storm overflows on this river
Frequently asked questions
Is the Bourne Tributary Medway at Hadlow flooding today?
The current level is 0.23m, which is within the typical range of 0.17 to 1.55m. Flooding is unlikely at this level.
Is the river level rising or falling at Hadlow?
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.
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 0.0mm 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 Bourne Tributary Medway at Hadlow?
The typical range at this station is 0.17m 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 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.
Preview
📮 Flood risk by postcode near this gauge
Postcodes within 5 km with properties in the Environment Agency’s rivers-and-sea flood-risk bands:
18 Sep 2024 Cross correlation gauge - Looking upstream
18 Sep 2024 Cross correlation gauge - Looking downstream
4 Apr 2022 Looking downstream of station
4 Apr 2022 Looking upstream of station
View of weir looking upstream
