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0.16

Bramshill

Hart ⚙ Structure
Loddon catchment • Hazeley • Hampshire • ID: 2458TH • Level
(26m ago) • 3 readings/hr • 144 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
0.162 mASD
▬ Steady
24h Max
0.191 mASD
24h Min
0.109 mASD
Typical Range
0.10 - 1.33
mASD
Highest Recorded
1.81 mASD
EA official record
A 4.39 reading (7 Apr 2016) sits in our unverified raw history and is not treated as the record
Current level is 9% 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

Falling · -0.8 cm over 5h
10 Oct 11:00 ▼ -0.2 cm 0.162 mASD
10 Oct 10:45 ▲ +0.1 cm 0.164 mASD
10 Oct 10:15 ▬ steady 0.163 mASD
10 Oct 10:00 ▼ -0.1 cm 0.163 mASD
10 Oct 09:45 ▼ -0.3 cm 0.164 mASD
10 Oct 09:30 ▼ -0.1 cm 0.167 mASD
10 Oct 09:15 ▼ -0.2 cm 0.168 mASD
10 Oct 09:00 ▲ +0.5 cm 0.170 mASD
10 Oct 08:45 ▼ -0.3 cm 0.165 mASD
10 Oct 08:30 ▼ -0.2 cm 0.168 mASD
10 Oct 08:00 ▼ -0.2 cm 0.170 mASD
10 Oct 07:45 ▼ -0.1 cm 0.172 mASD
10 Oct 07:30 ▲ +0.3 cm 0.173 mASD
10 Oct 07:15 ▼ -0.3 cm 0.170 mASD
10 Oct 07:00 ▼ -0.1 cm 0.173 mASD
10 Oct 06:45 ▲ +0.1 cm 0.174 mASD
10 Oct 06:30 ▲ +0.2 cm 0.173 mASD
10 Oct 06:15 ▲ +0.2 cm 0.171 mASD
10 Oct 06:00 ▼ -0.1 cm 0.169 mASD
10 Oct 05:45 0.170 mASD

Station Details

  • Monitoring Station: Bramshill
  • Watercourse: River Hart
  • Nearest Town: Hazeley
  • County: Hampshire
  • Coordinates: 51°19'36"N 0°55'3"W (51.326710, -0.917374)
  • 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: 2458TH
  • RLOI id: 7148 (the EA's check-for-flooding station id)
  • EA Gauge ID: 2458TH-level-stage-i-15_min-mASD
  • Parameter: Level
  • Unit: mASD
  • Typical rise rate: 8 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: 0.095 – 1.325 mASD
  • Drainage Area: 84 km² upstream of this gauge
  • 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
  • EA Cross-check: 0.16 mASD (EA at 10 Oct 10:45)
  • 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

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.

4 storm overflows are traced upstream of this gauge, the nearest 2.2 km away along the river. 0 report discharging now, 4 report not discharging.

💧
Thames Water · into Tributary Of The River Hart · 2.2 km upstream along the river
21 spills · 300 hours in 2025
Not discharging now · last
💧
Thames Water · into Fleet Brook · 7.6 km upstream along the river
39 spills · 525 hours in 2025
Not discharging now · last
💧
Thames Water · into Fleet Brook · 10.7 km upstream along the river
0 spills · 0 hours in 2025
Not discharging now
💧
Thames Water · into River Hart · 14.9 km upstream along the river
58 spills · 823 hours in 2025
Not discharging now · last

3 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 1.33 m on about 1 day. This year so far: 0 days.

2026 0 days so far
2025 2 days
2024 2 days
2023 0 days
2022 0 days
2021 1 day
2020 2 days
2019 1 day
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 2011 for the 8 flood areas linked to this gauge (nearest 1.8 km away).

0flood warnings 124flood alerts

Most recent flood alert: 21 Jan 2026 — River Blackwater and The Cove Brook

Year by year
YearWarningsAlerts
2026 0 2
2025 0 7
2024 0 15
2023 0 10
2022 0 5
2021 0 8
2020 0 9
2019 0 6
2018 0 7
2017 0 5
2016 0 13
2015 0 10
2014 0 15
2013 0 5
2012 0 6
2011 0 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 Hazeley flood history.

Flood areas linked to this gauge

Flood warnings and alerts are issued for whole areas. These are the 8 areas linked to this gauge, nearest first.

Catchment Character

🌊 Mixed response A 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
0.59
mixed response
Avg Annual Rainfall
751 mm/yr
1991–2020 · +7% since 1941–70
Urban Extent
8.4%
partly urbanised
Highest Daily Mean Flow
10.10 m³/s
16 Feb 2020 · daily mean, not the instantaneous peak
Flow-Duration Curve
mean 0.8142.180.5910.2335% (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 26%Grassland 35%Arable 18%Heath/scrub 3%Urban 18%Other 1%
Urban 11% → 18% since 1990

Flow affected by: 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 on the River Hart above the confluence with the River Whitewater.

More detail

The catchment

Chalk headwaters but a mainly impermeable (Eocene formations with a limited overburden of glacial deposits) catchment. Mixed land use. Rural tracts with considerable woodland but also includes growing urban development in the headwaters including Camberley and Farnborough.

The station

Crump weir, 4.0m broad. Removed from peak flows dataset in September 2023 (WINFAP Files v12).

How it measures flow

Standard Crump weir calculation with non-modular corrections. Weir is non-modular throughout most of the range, requiring considerable adjustments to flows. Crest tapping used until 2014 for non-modular corrections, replaced by tail water level recording. Banks overtopped in extreme floods.

Flow regime

Flows augmented by effluent derived from outside the catchment.

The flow record

Weir is drowned during majority of peak flow events, and flow is often out of bank. Also poor low flow record due to weed-induced drowning.

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
1972
Station datum
49.8 mAOD
Flow record
1972–2024 · 52 yrs · 100% complete
Hydrometric area
39
Measured by
Environment Agency

Frequently asked questions

Is the River Hart at Bramshill flooding today?

The current level is 0.16m, which is within the typical range of 0.10 to 1.33m. Flooding is unlikely at this level.

Is the river level rising or falling at Bramshill?

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. 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 Hart at Bramshill?

The typical range at this station is 0.10m to 1.33m, based on Environment Agency historical data. Levels above 1.33m 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 →