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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.
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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Not an emergency service — if in danger call 999. Alerts rely on
EA/SEPA/NRW data and are best-efforts. Terms
Current Level
0.105 mASD
▬ Steady
24h Max
0.105 mASD
24h Min
0.104 mASD
Typical Range
0.10 - 0.80
mASD
Highest Recorded
1.61 mASD
EA official record
1.43 in our data (since Oct 1981)
Current level is 7% 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 8 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 3.8 km away along the river. 0 report discharging now, 2 report not discharging.
Thames Water · into Toll House Stream · 4.4 km away in a straight line · no mapped watercourse close enough to be sure
5 spills · 38 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 →
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 Wareside flood history.
Flood areas linked to this gauge
Flood warnings and alerts are issued for whole areas. These are the 12 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
0.51
mixed response
Avg Annual Rainfall
652 mm/yr
1991–2020 · +4% since 1941–70
Urban Extent
1.4%
largely rural
Median Annual Flood
6.74 m³/s
QMED — typical yearly peak flow
Highest Daily Mean Flow
11.30 m³/s
21 Oct 2001 · 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 that is located in the lower Ash catchment.
More detail
The catchment
Solid geology of Upper Chalk extensively overlain by boulder clay, glacial sands & gravel and alluvium in the valleys. Rural catchment in character.
The station
Flat V weir (1:10 cross-slope) 3.9m wide, constructed in 1979. The current station replaced the original hump flume weir that was built in 1939. The old station was not good due to the obstruction caused by the old gate at the mill bypass channel. It was insensitive, subject to bypassing and was inaccurate at low flows. Hence discharges was assessed at the d/s station at Easneye (38005).
How it measures flow
No rating available for original hump flume weir. Remains modular and is virtually full range. Rating is valid from 1981 - theoretical standard Flat V calculation, extended in January 2012, using modelled flow to account for stages 0.9mASD to 3mASD. Peak flow rating is reasonably accurate. Some bypassing is known to occur at extreme flows. One peak flow rating across period of record which takes account of bypassing.
Flow regime
Baseflow dominated regime but significant runoff generated from the clays in the headwaters. U/s lake storage, sluice activity and gw abstractions for industry/agriculture have a minor effect on flows.
The flow record
Full period of record peak flow data reviewed and released in August 2024 (WINFAP Files v13).
Timing, not cause. Gauges can move together simply because the same rain fell on both.
Frequently asked questions
Is the River Ash at Mardock flooding today?
The current level is 0.11m, which is within the typical range of 0.10 to 0.80m. Flooding is unlikely at this level.
Is the river level rising or falling at Mardock?
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 Ash at Mardock?
The typical range at this station is 0.10m to 0.80m, based on Environment Agency historical data. Levels above 0.80m 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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