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⤴Unusual rise — FloodRadar+Top 1% rise rate for this gauge.
Height for "Above a height"
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.
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Current Level
0.099 mASD
▬ Steady
24h Max
0.100 mASD
24h Min
0.098 mASD
Typical Range
0.03 - 1.04
mASD
Highest Recorded
2.21 mASD
9 Feb 2014
Since Nov 2012
Current level is 4% 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 00:00▬ steady0.099 mASD
23 Aug 23:45▬ steady0.099 mASD
23 Aug 23:30▬ steady0.099 mASD
23 Aug 23:15▬ steady0.099 mASD
23 Aug 23:00▬ steady0.099 mASD
23 Aug 22:45▲ +0.1 cm0.099 mASD
23 Aug 21:30▬ steady0.098 mASD
23 Aug 21:15▬ steady0.098 mASD
23 Aug 21:00▬ steady0.098 mASD
23 Aug 20:45▬ steady0.098 mASD
23 Aug 20:30▬ steady0.098 mASD
23 Aug 20:15▬ steady0.098 mASD
23 Aug 20:00▬ steady0.098 mASD
23 Aug 19:45▬ steady0.098 mASD
23 Aug 19:30▬ steady0.098 mASD
23 Aug 19:15▬ steady0.098 mASD
23 Aug 19:00▬ steady0.098 mASD
23 Aug 18:45▬ steady0.098 mASD
23 Aug 18:30▬ steady0.098 mASD
23 Aug 18:150.098 mASD
Rainfall & Weather
Loading rainfall and weather data...
Flood history near this gauge
Official Environment Agency warnings issued since 2012 for the 8 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 Ewell 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
0.88
groundwater-fed — slow & steady
Avg Annual Rainfall
700 mm/yr
1991–2020 · -1% since 1941–70
Urban Extent
37%
heavily urbanised
Highest Recorded Flow
0.247 m³/s
17 May 2001
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.
Land Cover (2023)
Woodland 3%Grassland 30%Urban 66%
About this gauge
Rectangular flume; stage-discharge relation confirmed by c/m gaugings.
More detail
The catchment
A largely suburban catchment developed mostly on Chalk (dip-slope of North Downs). Mean runoff suggests that topographical catchment greatly exceeds the contributing area.
The station
Rectangular flume; Modular. Overfall u/s. Frequently vandalised. Station downgraded in 2010 to level only.
How it measures flow
Grounding of float (stilling well floor corresponds to throat level of flume) can affect low flow accuracy. Debris on u/s grill can influence levels.
How this gauging station is built and how long it has measured (NRFA / UKCEH).
Gauge type
Gauging structure
Operating since
1988–2010
Station datum
28.6 mAOD
Flow record
1988–2010 · 22 yrs · 84% 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 Hogsmill River at Ewell flooding today?
The current level is 0.10m, which is within the typical range of 0.03 to 1.04m. Flooding is unlikely at this level.
Is the river level rising or falling at Ewell?
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 Hogsmill River at Ewell?
The typical range at this station is 0.03m to 1.04m, based on Environment Agency historical data. Levels above 1.04m 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:
