UK Culvert Register · Risk Scoring · Terrain Screening

Every culvert.
Scored. Prioritised.

We map every culvert in your authority area, score each one for flood risk and blockage likelihood, and turn it into a prioritised register your team can work down, so you know where to look before the next storm, not after.

See your authority area How it works

Risk-scored culvert map: real data, live platform

27,000+road–watercourse crossings mapped nationally
4-tierrisk classification, every culvert
152Lead Local Flood Authorities in England
The Problem

Small culverts.
Big consequences.

Most culvert blockages aren't found until water is already on the road. Inspections happen on a two-yearly reactive cycle, if at all, and there's no continuous record between visits. When a major event hits, Section 19 of the Flood and Water Management Act 2010 obliges Lead Local Flood Authorities to investigate; without a register of known assets, that investigation starts from scratch. Storm Babet in October 2023 made the gap visible across Yorkshire, Lincolnshire and the East Midlands.

S.19

Required after significant flood events. Continuous data supports your statutory duty.

2-yearly

Typical reactive inspection cycle. Blocked inlets fill silently between visits.

£2,500

Typical cost of one gully clean and road closure after a culvert blockage.

152

Lead Local Flood Authorities in England, each with a statutory duty for ordinary watercourses and culverts.

The Register

Your culvert register.
Pre-built and risk-scored.

Two tiers. A national open-data baseline you can view today, and a deeper, enhanced pass when you work with us.

National baseline

Available today

27,000+ road–watercourse crossings already identified across England from OS and Environment Agency open data, each risk-scored by flood probability, infrastructure proximity, and flood history. Your authority area is ready to view today.

Detailed analysis

When you work with us

We run your area through the full detection pipeline using the OS NGD Water Network, including the buried and culverted sections free data misses. Pilot councils typically see significantly more crossings detected, each classified as culvert, bridge or ford from OS survey data.

How crossings are classified
Confirmed culvert

OS NGD Underground classification + surveyed entrance points.

Likely culvert

NGD Underground crossing without surveyed points.

Bridge or ford

NGD Surface Level crossing.

Surveyed buried

OS-surveyed culvert entrance with no road–water intersection: urban and Victorian assets that intersection-based detection misses.

See the register for your authority area
Risk Scoring

Every culvert classified.
Likelihood × Consequence.

Every culvert in your register is scored on two independent axes (how likely it is to fail, and how bad the consequences would be if it did), then combined into a single number you can sort and prioritise by.

Blockage likelihood

How likely to fail

We analyse upstream land cover, channel gradient, vegetation canopy, inlet aspect, watercourse size, pipe gradient, and historical flood evidence to estimate how likely each culvert is to block.

Flood consequence

How bad if it fails

EA surface water flood probability, proximity to housing, schools, hospitals, emergency services, road classification, and flood history, combined to estimate the impact of a failure.

Likelihood × Consequence = a risk classification for every culvert (Critical, High, Moderate, or Low), with the contributing factors visible so your team understands exactly why each culvert was flagged.

Critical
Risk classification

Likelihood: High  ×  Consequence: High

Woodland upstream Steep gradient South-facing inlet Housing ≤ 50m Surface water: High
Terrain Screening

LiDAR terrain analysis
at every crossing.

Using Environment Agency 1m LiDAR data, we analyse the terrain at each culvert crossing to estimate channel depth, embankment height, and pipe gradient, identifying potential structural issues without a site visit.

Longitudinal cross-section of Macon Way / unnamed watercourse, Cheshire East: elevation profile sampled along the NGD waterlink centreline at 1m intervals over 60m, with red upstream and green downstream segments and a grey road-crossing zone at d=0.

Channel depression depthEstimates how deep the watercourse cuts below the surrounding terrain.

Embankment heightMeasures how high the road sits above the channel, approximating the available space for a culvert pipe.

Adverse gradient detectionFlags culverts where the outlet appears higher than the inlet, indicating siltation risk or structural settlement.

Ponding indicatorsIdentifies upstream depressions where water may pool against the road embankment.

Terrain screening is indicative, not measured: it identifies sites worth investigating. Field verification confirms the findings.

Return on Investment

The cost of one flood event
dwarfs the register that prevents it.

One culvert blockage at Eel Brook, Church Minshull generated £476,000 in insurance claims, triggered an MP inquiry and a formal Section 19 investigation. A year of CulvertSense across an entire authority is a fraction of the cost of one event like this.

£476k

insurance claims from a single blocked culvert (Eel Brook, Church Minshull)

839,000

homes at high risk of surface water flooding in England (NHF/EA, 2026)

Pilot Programme

Low risk.
Measurable outcomes.

We're working with our first cohort of Lead Local Flood Authorities. Three stages, each evidence-gated before you commit to the next, and nothing to install at any point.

1 Register
Detect & prioritise

Your authority's full culvert register: every crossing detected, classified, risk-scored 0–100, and mapped. Review with your team, prioritise, and layer in your local knowledge. Browser-based, nothing to install.

2 Inspect
Ground-truth the priorities

Your team inspects the highest-scored crossings first. Field findings feed back into the register, sharpening the scores and building the evidence base behind every maintenance decision.

3 Refresh
A register that stays current

Annual re-screening against the latest lidar and inspection records. New crossings detected, scores updated, and a defensible audit trail for section 21 duties, year after year.

Request a pilot

Tell us about your council and the culverts that worry you most. We'll confirm whether it's a good fit and walk you through what comes next. No commitment.

Or email directly: james@culvertsense.com

Built on Ordnance Survey NGD Water Network · Environment Agency LiDAR & flood risk data · OpenStreetMap