Parrett, Brue and West Somerset Streams catchment
• Yeovil • Somerset • ID: 52117 • Level
(31m ago) • 4 readings/hr • 143 views
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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 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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Current Level
0.120 mASD
▬ Steady
24h Max
0.129 mASD
24h Min
0.120 mASD
Typical Range
0.12 - 3.10
mASD
Highest Recorded
4.57 mASD
EA official record
4.49 in our data (since Nov 1963)
Current level is 3% 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.
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.
Flow Data: Daily mean flow (m³/s) to 7 Oct (2 days behind — the EA publishes each day's mean a day or two after it ends; unchecked, provisional)via EA Hydrology
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.
19 storm overflows are traced upstream of this gauge, the nearest 1.2 km away along the river. 0 report discharging now, 19 report not discharging.
Wessex Water · into A Tributary Of The River Yeo · 2.7 km away in a straight line · its watercourse is not on the river map
1 spill · 1 hours in 2025
Not discharging now · last
6 more within 6 km whose connection is not known.
1 other overflow within 6 km is downstream of this gauge or on another branch of the river network, so it is 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 Yeovil flood history.
Flood areas linked to this gauge
Flood warnings and alerts are issued for whole areas. These are the 11 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
0.57
mixed response
Avg Annual Rainfall
933 mm/yr
1991–2020 · +3% since 1941–70
Urban Extent
2.9%
largely rural
Median Annual Flood
49.22 m³/s
QMED — typical yearly peak flow
Highest Daily Mean Flow
113 m³/s
5 Nov 1966 · 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.
Land Cover (2023)
Woodland 8%Grassland 65%Arable 19%Urban 8%
Arable 28% → 19% since 1990
Flow affected by: surface-water abstraction, public water supply, groundwater abstraction.
Photos
Gauging-station photographs from the National River Flow Archive (UKCEH).
Crump profile weir for low flows, set within trapezoidal concrete flanks and topped with the natural banks, becomes velocity-area station at high flows. Sutton Bingham Reservoir in headwaters.
More detail
The catchment
Fairly responsive catchment with Oxford Clay and Great Oolite in the upper catchment, Yeovil Sands and Inferior Oolite in the lower catchment. Land use is predominantly rural. No major catchment changes.
The station
Station was installed in November 1963 and is located next to a sewage treatment works. Crump profile weir for low flows, set within trapezoidal concrete flanks and topped with the natural banks, becomes velocity-area station at high flows. Station moved slightly in 1989, due to stilling-well problems; bank repairs undertaken in 1997/98.
How it measures flow
Two peak levels recorded before weir finished but flows can be calculated from rating as station becomes velocity area at high flows. Velocity area station (affected by downstream weed growth) used to measure flows >1.55 m3/s. Flows >2m are less reliable. All but highest floods contained. Some out of bank events on right bank but modelled so these flows are included. Highest flows can be gauged at upstream bridge. Cableway cannot be used above 3.8 m, in which case road bridge is used, up to 4.25 m. Floodplain water does not flow appreciably, though may extend 200 m from river. Rating reviewed in Jan 2001. One rating applied across period of record. Bank repairs 1997/98 might have affected the rating and may influence cableway gaugings. Issues with silt build up.
Flow regime
Sutton Bingham Reservoir in headwaters. Abstraction for public water supply. Medium & low flows influenced by variable abstractions & compensation.
The flow record
Full period of record peak flow data reviewed and released in September 2019 (WINFAP Files v8) and August 2025 (WINFAP Files v14). Peak flows from 30/12/1977 to 04/01/1979 are rejected as only 2 stages per day are available back calculated from the daily mean flow.
Timing, not cause. Gauges can move together simply because the same rain fell on both.
Frequently asked questions
Is the River Yeo at Pen Mill flooding today?
The current level is 0.12m, which is within the typical range of 0.12 to 3.10m. Flooding is unlikely at this level.
Is the river level rising or falling at Pen Mill?
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 9.8mm 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 River Yeo at Pen Mill?
The typical range at this station is 0.12m to 3.10m, based on Environment Agency historical data. Levels above 3.10m 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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