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0.09

Rickmansworth

Chess ⚙ Structure
Colne (Upper) catchment • Rickmansworth • Hertfordshire • ID: 2859TH • Level
(1h ago) • 4 readings/hr • 170 views

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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
0.086 mASD
▬ Steady
24h Max
0.088 mASD
24h Min
0.084 mASD
Typical Range
0.06 - 0.34
mASD
Highest Recorded
0.37 mASD
EA official record
0.36 in our data (since Nov 1985)
Current level is 23% of this
🚽 Sewage overflows nearby

Recent Water Levels

🌍 floodradar.co.uk
1 day

Flood predictions aren't generated for lock / structure gauges — their levels are driven by gate operation, not by catchment rainfall, so the forecast models would have no skill here.

Recent Readings

Steady over 6h
08 Oct 01:30 ▬ steady 0.086 mASD
08 Oct 01:15 ▬ steady 0.086 mASD
08 Oct 01:00 ▬ steady 0.086 mASD
08 Oct 00:45 ▬ steady 0.085 mASD
08 Oct 00:30 ▬ steady 0.085 mASD
08 Oct 00:15 ▬ steady 0.086 mASD
08 Oct 00:00 ▬ steady 0.086 mASD
07 Oct 23:45 ▬ steady 0.085 mASD
07 Oct 23:30 ▬ steady 0.085 mASD
07 Oct 22:30 ▬ steady 0.085 mASD
07 Oct 22:15 ▬ steady 0.085 mASD
07 Oct 22:00 ▬ steady 0.085 mASD
07 Oct 21:45 ▬ steady 0.085 mASD
07 Oct 21:30 ▬ steady 0.085 mASD
07 Oct 21:15 ▬ steady 0.085 mASD
07 Oct 21:00 ▬ steady 0.085 mASD
07 Oct 20:45 ▬ steady 0.085 mASD
07 Oct 20:30 ▬ steady 0.085 mASD
07 Oct 20:15 ▬ steady 0.085 mASD
07 Oct 20:00 0.085 mASD

Station Details

  • Monitoring Station: Rickmansworth
  • Watercourse: River Chess
  • Nearest Town: Rickmansworth
  • County: Hertfordshire
  • Coordinates: 51°38'31"N 0°27'40"W (51.641989, -0.461250)
  • Open in: Google Maps · Apple Maps (opens your maps app)
  • Date Opened: 1 Jan 1985
  • Status: Active
  • Station Type: River level station (multi-sensor)
Technical details: references, datum, range, flow archive
  • Station Reference: 2859TH
  • RLOI id: 7190 (the EA's check-for-flooding station id)
  • EA Gauge ID: 2859TH-level-stage-i-15_min-mASD
  • Parameter: Level
  • Unit: mASD
  • Typical rise rate: 0 cm/hr (p95 sustained over 90 days)
  • Typical data delay: ~22 min (measured reading→publication lag)
  • Tidal: No
  • Lock / structure: ⚙ Yes — lock, weir, sluice or pump
  • Catchment Area: Colne (Upper)
  • Typical Range: 0.059 – 0.340 mASD
  • Drainage Area: 105 km² upstream of this gauge
  • Flow Data: Daily mean flow (m³/s) to 6 Oct (2 days behind — the EA publishes each day's mean a day or two after it ends; unchecked, provisional) via EA Hydrology
  • EA Cross-check: 0.00 mASD (EA at 8 Oct 01:45)
  • Flow Archive: National River Flow Archive ↗

Geographic coordinates may reflect the access point for the gauge, and not the precise location in the watercourse that it is taking readings from.

Nearby Stations

Gauges connected to this river, and others nearby. A distance “by river” follows the river on the map; any other is in a straight line.

Connected upstream

Connected downstream

Same river system, separate branch

Nearby

Distances by river: OS Open Rivers. Contains OS data © Crown copyright and database rights 2026.

💧 Storm overflows upstream of this gauge

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.

1 storm overflow is traced upstream of this gauge, the nearest 12.2 km away along the river. 0 report discharging now, 1 reports not discharging.

💧
Thames Water · into The River Chess · 12.2 km upstream along the river
7 spills · 58 hours in 2025
Not discharging now · last

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 →

Contains OS data © Crown copyright and database rights 2026.

Rainfall & Weather

Loading rainfall and weather data...

How often this river runs high

This gauge rarely reaches its typical high of 0.34 m: 3 days since 2017. This year so far: 0 days.

2026 0 days so far
2025 0 days
2024 3 days
2023 0 days
2022 0 days
2021 0 days
2020 0 days
2019 0 days
2018 0 days
2017 0 days

Counted from each day's highest reading. Days with missing or implausible readings are left out.

Flood history near this gauge

Official Environment Agency warnings issued since 2014 for the 7 flood areas linked to this gauge (nearest 0.6 km away).

1flood warning 13flood alerts

Most recent flood warning: 7 Feb 2014 — River Gade at Kings Langley and Croxley

Year by year
YearWarningsAlerts
2024 0 5
2021 0 5
2020 0 1
2016 0 1
2014 1 1

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 Rickmansworth 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.

Catchment Character

🌊 Groundwater-fed Slow 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
0.69
groundwater-fed — slow & steady
Avg Annual Rainfall
786 mm/yr
1991–2020 · +3% since 1941–70
Urban Extent
5.6%
partly urbanised
Median Annual Flood
1.14 m³/s
QMED — typical yearly peak flow
Highest Daily Mean Flow
2.81 m³/s
28 Apr 2024 · daily mean, not the instantaneous peak
Flow-Duration Curve
mean 0.5441.100.4890.1815% (high)% of days exceeded95% (low)
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 15%Grassland 50%Arable 24%Urban 12%
Arable 34% → 24% since 1990

Flow affected by: public water supply, groundwater abstraction, effluent returns.

Photos

Gauging-station photographs from the National River Flow Archive (UKCEH).

Photos © NRFA / UKCEH & the measuring authority — shown at web resolution. Full gallery on the NRFA ↗

About this gauge

The station is located in the lower catchment of the River Chess.

More detail

The catchment

The Chess is a Chalk stream draining the dip-slope of the Chilterns (significant Drift cover). Headwaters are rural with significant urban growth in the lower valley. Chesham is the largest town.

The station

A crump weir (6.0m broad) with downstream recorder for non-modularity adjustment. Used for both water resource and flood warning/forecasting purposes. The Chess is a chalk stream with intemittence in the upper catchment.

How it measures flow

Full range station but non-modular at high flows (tail levels monitored). Weir equation used since construction. Gravel accumulates above the weir. Protected flows derived from standard Crump weir equation using tail levels. A very small channel that is fed from a spring approximately 150m upstream, bypasses the weir and enters the river just downstream. The modular limit of the weir is head:tail ratio of 0.75 (~0.23m), extremely non-modular limit is head:tail ratio 0.92. All flows are adjusted for non-modularity, however, extremely non-modular flows are reduced too low, with deviations from the spot flow measurement of between 12 and 35% and resulting uncertainty in AMAX and POT series that is being investigated to improve flows.

Flow regime

Baseflow-dominated flow regime but artificial influences (primarily STW effluent) evident on the hydrograph. Abstractions are of a mainly low consumptive type with some groundwater abstractions for public water supply. There is a small net export from the catchment.

The flow record

Generally a very reliable record in all but extremely non-modular flows. Periods of extremely non-modular flows in Feb 2001 and winter 2022/2023. Tail level adjustments used but surrounding data suggests the reduction factor has underestimated the true flow (see Hydrometric description). Full period of record peak flow data reviewed and released in August 2021 (WINFAP Files v10).

Descriptions from the National River Flow Archive (UKCEH). NRFA station record ↗

Gauge Details

How this gauging station is built and how long it has measured (NRFA / UKCEH).

Gauge type
Crump weir
Operating since
1974
Station datum
47.1 mAOD
Flow record
1974–2024 · 50 yrs · 100% complete
Peak-flow record
since 1974
Hydrometric area
39
Measured by
Environment Agency

Frequently asked questions

Is the River Chess at Rickmansworth flooding today?

The current level is 0.09m, which is within the typical range of 0.06 to 0.34m. Flooding is unlikely at this level.

Is the river level rising or falling at Rickmansworth?

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 Chess at Rickmansworth?

The typical range at this station is 0.06m to 0.34m, based on Environment Agency historical data. Levels above 0.34m 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:

Check any UK postcode’s flood risk →

🏠 Buying or renting around here? Get the Property Flood-Risk Report for any English postcode — official risk band, recorded floods, warning history, river behaviour and nearby storm overflows. £19 one-off. Learn more →