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Water Level Rising Slightly
Up 0.07 m since 20:15, rising slightly
0.26

Swallowfield Side Channel

Blackwater ⚙ Structure
Loddon catchment • Swallowfield • Wokingham • ID: 2469_w2TH • Level
(32m ago) • 4 readings/hr • 126 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
0.255 mASD
▲ Rising slightly
24h Max
0.255 mASD
24h Min
0.179 mASD
Typical Range
0.19 - 0.73
mASD
Highest Recorded
1.69 mASD
EA official record
A 2.26 reading (11 Jun 2025) sits in our unverified raw history and is not treated as the record
Current level is 15% 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

Rising · +2 cm over 5h
08 Oct 05:15 ▬ steady 0.255 mASD
08 Oct 05:00 ▬ steady 0.255 mASD
08 Oct 04:45 ▬ steady 0.255 mASD
08 Oct 04:30 ▬ steady 0.255 mASD
08 Oct 04:00 ▬ steady 0.255 mASD
08 Oct 03:45 ▬ steady 0.255 mASD
08 Oct 03:30 ▲ +0.1 cm 0.255 mASD
08 Oct 03:15 ▼ -0.1 cm 0.254 mASD
08 Oct 03:00 ▲ +0.1 cm 0.255 mASD
08 Oct 02:45 ▲ +0.1 cm 0.254 mASD
08 Oct 02:30 ▲ +0.1 cm 0.253 mASD
08 Oct 02:15 ▲ +0.1 cm 0.252 mASD
08 Oct 02:00 ▲ +0.1 cm 0.251 mASD
08 Oct 01:45 ▲ +0.2 cm 0.250 mASD
08 Oct 01:30 ▲ +0.2 cm 0.248 mASD
08 Oct 01:15 ▲ +0.1 cm 0.246 mASD
08 Oct 01:00 ▲ +0.2 cm 0.245 mASD
08 Oct 00:45 ▲ +0.3 cm 0.243 mASD
08 Oct 00:30 ▲ +0.3 cm 0.240 mASD
08 Oct 00:15 0.237 mASD

Station Details

  • Monitoring Station: Swallowfield Side Channel
  • Watercourse: River Blackwater
  • Nearest Town: Swallowfield
  • County: Wokingham
  • Coordinates: 51°22'39"N 0°57'9"W (51.377564, -0.952526)
  • Open in: Google Maps · Apple Maps (opens your maps app)
  • Date Opened: 1 Jan 1986
  • Status: Active
  • Station Type: River level station
Technical details: references, datum, range, flow archive
  • Station Reference: 2469_w2TH
  • Also at this site: Swallowfield (2469_w1TH, level, reporting)
  • RLOI id: 7150 (the EA's check-for-flooding station id)
  • EA Gauge ID: 2469_w2TH-level-stage-i-15_min-mASD
  • Parameter: Level
  • Unit: mASD
  • Typical rise rate: 1 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: Loddon
  • Typical Range: 0.189 – 0.728 mASD
  • EA Cross-check: 0.26 mASD (EA at 8 Oct 05:15)

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

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.

12 storm overflows are traced upstream of this gauge, the nearest 4.4 km away along the river. 0 report discharging now, 11 report not discharging, and for 1 the monitor is offline or has not reported, so their status is not known.

💧
Thames Water · into Tributary Of River Blackwater · 4.4 km upstream along the river
27 spills · 325 hours in 2025
Not discharging now · last
💧
Thames Water · into Tributary Of The River Hart · 10.3 km upstream along the river
21 spills · 300 hours in 2025
Not discharging now · last
💧
Thames Water · into Rotherwick Brook · 11.3 km upstream along the river
8 spills · 74 hours in 2025
Not discharging now · last
Placed on the river by its position alone.
💧
Thames Water · into River Whitewater · 14.0 km upstream along the river
7 spills · 13 hours in 2025
Not discharging now · last
💧
Thames Water · into Blackwater · 14.2 km upstream along the river
10 spills · 115 hours in 2025
Not discharging now · last
💧
Thames Water · into Fleet Brook · 15.7 km upstream along the river
39 spills · 525 hours in 2025
Not discharging now · last
💧
Thames Water · into Blackwater · 17.7 km upstream along the river
7 spills · 69 hours in 2025
Not discharging now · last
💧
Thames Water · into Fleet Brook · 18.8 km upstream along the river
0 spills · 0 hours in 2025
Monitor offline: it cannot say whether it is discharging

4 more further upstream, up to 28.7 km away along the river.

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 →

Contains OS data © Crown copyright and database rights 2026.

Rainfall & Weather

Loading rainfall and weather data...

How often this river runs high

In a typical year this gauge reaches its typical high of 0.73 m on about 44 days. This year so far: 41 days.

2026 41 days, 7 of them high · 7 high so far
2025 33 days, 8 of them high · 8 high
2024 76 days, 14 of them high · 14 high
2023 66 days, 8 of them high · 8 high
2022 34 days, 1 of them high · 1 high
2021 45 days, 7 of them high · 7 high
2020 26 days, 2 of them high · 2 high patchy data
2019 8 days patchy data
2018 37 days
2017 15 days

Counted from each day's highest reading. Days with missing or implausible readings are left out, so a year marked patchy may have run high more often than shown. The darker part is days above 1.31 m, the level this gauge tops only a few days a year.

Flood history near this gauge

Official Environment Agency warnings issued since 2011 for the 10 flood areas linked to this gauge (nearest 0.8 km away).

12flood warnings 202flood alerts

Most recent flood warning: 27 Jan 2025 — River Loddon and River Blackwater at Swallowfield

Year by year
YearWarningsAlerts
2026 0 8
2025 1 11
2024 1 21
2023 2 15
2022 0 6
2021 1 12
2020 1 14
2019 2 10
2018 0 12
2017 0 10
2016 0 19
2015 0 10
2014 3 22
2013 1 10
2012 0 19
2011 0 3

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 Swallowfield flood history.

Flood areas linked to this gauge

Flood warnings and alerts are issued for whole areas. These are the 10 areas linked to this gauge, nearest first.

Show 2 more

Frequently asked questions

Is the River Blackwater at Swallowfield Side Channel flooding today?

The current level is 0.26m, which is within the typical range of 0.19 to 0.73m. Flooding is unlikely at this level.

Is the river level rising or falling at Swallowfield Side Channel?

Based on the most recent readings, the level is currently rising slightly. 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 Blackwater at Swallowfield Side Channel?

The typical range at this station is 0.19m to 0.73m, based on Environment Agency historical data. Levels above 0.73m 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 →