The official "typical high" for this gauge is routinely exceeded (often the case on
regulated rivers), so FloodRadar uses a threshold computed from this station's own data.
(43m ago) • 2 readings/hr • 185 views
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You'll be notified when this gauge is rising more than 0.10 m/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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Not an emergency service — if in danger call 999. Alerts rely on
EA/SEPA/NRW data and are best-efforts. Terms
Current Level
0.257 m
▬ Steady
24h Max
0.262 m
24h Min
0.255 m
Typical Range
0.24 - 1.43
m
Highest Recorded
1.45 m
EA official record
A 1.76 reading (27 Jan 2026) sits in our unverified raw history and is not treated as the record
Current level is 18% of this
🚽Sewage overflows nearby
Recent Water Levels
🌍 floodradar.co.uk
1 day
EA forecast (official)
Prediction V2
Prediction Eris
Nimbus beta
Experimental model fusing soil moisture, river flow, groundwater and catchment
character. The shaded band is its 10–90% range, widened so that about 80% of recent outcomes fall inside it.
Under evaluation — not yet promoted, so treat as a second opinion.
Storm overflows whose water reaches this gauge on the mapped river network, nearest first by distance along the river. The status is each water company's monitor: it says whether an overflow is discharging, not how much or what it contains.
2 storm overflows are traced upstream of this gauge, the nearest 3.1 km away along the river. 0 report discharging now, 2 report not discharging.
South West Water · into Carnon River · 4.0 km away in a straight line · its watercourse is not on the river map
38 spills · 423 hours in 2025
Not discharging now · last
9 more within 6 km whose connection is not known.
2 other overflows within 6 km are downstream of this gauge or on another branch of the river network, so they are not listed.
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 →
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 Bissoe flood history.
Flood areas linked to this gauge
Flood warnings and alerts are issued for whole areas. These are the 7 areas linked to this gauge, nearest first.
🌊 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
0.62
mixed response
Avg Annual Rainfall
1,250 mm/yr
1991–2020 · +7% since 1941–70
Urban Extent
2.6%
largely rural
Median Annual Flood
4.84 m³/s
QMED — typical yearly peak flow
Highest Daily Mean Flow
7.11 m³/s
1 Jan 2003 · daily mean, not the instantaneous peak
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.
Flat V weir opened in 1994 gauging a mainly rural catchment.
More detail
The catchment
The catchment consists mostly of Devonian slates and sandstones and Granite. Also with some areas of alluvium, Greenstones and Quartz Porphyry. Land use mostly rural with some urbanisation. No major changes in catchment.
The station
Station opened in 1994. Flat V weir, crest length approximately 4.0m wide.
How it measures flow
Relatively straight approach. High sediment loads. Bankfull at 2.5m. Three peak flow ratings across period of record. Change in downstream maintenance regime has resulted in gradual infilling of channel and drowning of the weir from an increasingly lower level (0.33m). Early drowning and In addition impacts from backing up from Bissoe bridge has resulted in a rating change from October 2011 based on extensive gauging. Acoustic Time of Flight was installed in 2013 due to the unstable stage discharge relationship. Therefore good confidence in data from 2011 onwards.
Flow regime
No major influences to flow regime.
The flow record
Data removed from 2020 temporarily due to reliability issues.
How this gauging station is built and how long it has measured (NRFA / UKCEH).
Gauge type
Flat-V weir
Operating since
1994
Flow record
1994–2020 · 26 yrs · 100% complete
Peak-flow record
since 1994
Hydrometric area
48
Measured by
Environment Agency
Nearby Groundwater
Soil Moisture
Possible storm-overflow correlation
Rain upstream
This gauge has no rain model of its own, but it usually follows Ponsanooth: when about 10mm of rain falls near Ponsanooth in 6h, this gauge usually starts rising about 45 minutes later.
Timing, not cause. Gauges can move together simply because the same rain fell on both.
Frequently asked questions
Is the Carnon River at Bissoe flooding today?
The current level is 0.26m, which is within the typical range of 0.24 to 1.43m. Flooding is unlikely at this level.
Is the river level rising or falling at Bissoe?
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.
What is a normal level for the Carnon River at Bissoe?
The typical range at this station is 0.24m to 1.43m, based on Environment Agency historical data. Levels above 1.43m 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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