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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
0.022 m
▬ Steady
24h Max
0.022 m
24h Min
0.014 m
Typical Range
0.04 - 0.50
m
Highest Recorded
1.12 m
EA official record
A 1.88 reading (28 Feb 1980) sits in our unverified raw history and is not treated as the record
Current level is 2% 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.
2 storm overflows are traced upstream of this gauge, the nearest 3.0 km away along the river. 0 report discharging now, 2 report not discharging.
Anglian Water · into Unknown Trib. Nine Foot Drain · 3.9 km away in a straight line · no mapped watercourse close enough to be sure
4 spills · 6 hours in 2025
Not discharging now · last
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 →
In a typical year this gauge reaches its typical high of 0.50 m
on about 11 days.
This year so far: 16 days.
202616 days so far
20250 days
202428 days
202315 days
20220 days
202128 days
20200 days
201928 days
20180 days
20170 days
Counted from each day's highest reading. Days with missing or implausible readings are left out.
The darker part is days above 1.20 m, the level this gauge tops only a few days a year.
Flood history near this gauge
Official Environment Agency warnings issued since 2016 for the 7 flood
areas linked to this gauge (nearest 2.5 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 Evedon 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.
🌊 Groundwater-fedSlow and steady — fed largely by groundwater, so levels change gradually, not in sudden spikes.
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
0.81
groundwater-fed — slow & steady
Avg Annual Rainfall
614 mm/yr
1991–2020 · -2% since 1941–70
Urban Extent
3.9%
partly urbanised
Median Annual Flood
1.84 m³/s
QMED — typical yearly peak flow
Highest Daily Mean Flow
5.74 m³/s
7 Jan 2024 · 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.
Rectangular thin plate weir gauging a predominantly rural catchment with gw-dominated regime and very low or zero summer/autumn flows. Significant artificial influences.
More detail
The catchment
Predominantly l'st with some superficial deposits including river terrace deposits (sand and gravel) in valley. Rural catchment, mixed agriculture, some urban development in lower catchment u/s of station.
The station
Rectangular thin-plate weir 1.372m wide set in old gate site, modified in 1984.
How it measures flow
Weir does not drown - modular limit pre weir 3 cumecs and post weir 12 cumecs. Theoretical rating, with section above thin-plate treated as broad-crested weir. Gaugings taken at footbridge in Sleaford (below Carre Lane). Two peak flow ratings applied across period of record, pre- and post- modification of the weir, with post-1984 rating accounting for bypass flow.
Flow regime
Unresponsive, gw-dominated catchment with intermittent flow regime. Runoff influenced by groundwater abstraction/recharge, including abstraction for industry, and agriculture. Groundwater abstraction has potential for reducing summer low flows. Limestone spring flow rises and falls rapidly depending on groundwater level.
The flow record
Full period of record peak flow data reviewed and released in September 2022 (WINFAP Files v11).
How this gauging station is built and how long it has measured (NRFA / UKCEH).
Gauge type
Gauging structure
Operating since
1974
Station datum
12.3 mAOD
Flow record
1974–2024 · 50 yrs · 98% complete
Peak-flow record
since 1974
Hydrometric area
30
Measured by
Environment Agency
Nearby Groundwater
Soil Moisture
Possible storm-overflow correlation
Frequently asked questions
Is the River Slea at Leasingham Mill flooding today?
The current level is 0.02m, which is below the typical range. Flooding is very unlikely at this level.
Is the river level rising or falling at Leasingham 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.
What is a normal level for the River Slea at Leasingham Mill?
The typical range at this station is 0.04m to 0.50m, based on Environment Agency historical data. Levels above 0.50m 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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