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Flash floods, warned in the minutes they allow.

A flash flood or a flooded street gives minutes, not hours. Rain gauges, depth sensors in streets and culverts and cameras at known flood points report to one record the city and the emergency services act on, and warnings go out through the authority’s own channels.

Industry

Public safety

Measurements

5

Sources cited

5

1. Public safety · Flash and urban floods

   Minutes, not hours

   A storm cell parks over a city and an underpass fills before the drains can take the water. A small stream rises faster than any river forecast can follow. Depth sensors at the places that flood, and rain gauges above them, give the minutes a road closure or a warning needs.

2. What is measured

   Rain, depth and levels

   Rain gauges across the city measure intensity. Ultrasonic or radar sensors on poles measure water depth at underpasses and dips, level sensors watch culvert inlets and small streams, and cameras confirm what the numbers show when an alarm sounds. Every reading names its street and point.

   Instruments

   Rain gauges · Street depth sensors · Culvert levels · Cameras

3. The base node

   Faster as the water rises

   Each endpoint sleeps between readings until water appears, then reports faster. The gateway’s node compares depths with the city’s thresholds, raises alarms with images at once and keeps every value signed, so the review after the storm has the whole event.

4. Radio and links

   LoRaWAN on the streets

   Battery sensors on street poles reach a gateway on a high building over LoRaWAN, with no cabling and years on a battery. Gateways reach the operations centre over cellular, with a satellite path at the centre for when terrestrial networks fail.

   Links

   LoRaWAN · Public cellular · Satellite

5. How it works

   From water in an underpass to a closed road

   A depth sensor sees water in an underpass and starts reporting faster. The gateway’s node sees the depth cross the closure threshold, raises the alarm with an image to the operations centre, and the road is closed. The authority warns, and the record keeps every step.

6. From order to operation · Order

   Scope the flood points and the warning

   The scope reads the flood risk plan, the history of flooded streets and underpasses, existing gauges and the city’s warning procedures. Nexus Observatory Inc. returns the flood point plan, the radio design, the integration with operations and warning systems and a price per point and per service.

   Plan a deployment

7. From order to operation · Survey

   Walk the low points

   Crews walk known flood points with the city’s engineers: underpasses, dips, culvert inlets and streams. They choose poles above the highest recorded water, check gateway coverage from high buildings and note where cameras can see the water without filming homes.

8. From order to operation · Permits

   Poles, streets and privacy

   Sensors on street poles need the owner’s consent; cameras follow the city’s privacy rules. Warning roles are agreed in writing, so the authority that warns decides. Every consent is kept with the point it covers. Residents near cameras are told what is measured and why.

9. From order to operation · Build

   Build for the street

   Depth and level sensors, endpoints, gauges and gateways are built, tested together and enrolled with their identities. Thresholds come from the city’s warning plan, and every part is labelled with the street and the point it serves. Spares are kept at the depot for quick swaps after storms.

   Open the Station Builder

10. From order to operation · Install

    Install between storms

    Crews mount sensors on poles above the flood level and set their reference to the road surface, install rain gauges on rooftops clear of obstructions and gateways on high buildings. Every point is photographed and located for the record. Each sensor’s height above the road is measured and kept.

11. From order to operation · Commission

    Test thresholds with the city

    Each endpoint proves its identity. Depth readings are checked against a measured reference, rain gauges with a measured volume, and alarms are tested to the operations centre and the warning authority with a staged threshold crossing. Each point joins the live map only when its checks pass.

12. From order to operation · Operate

    Close, clear and warn on evidence

    Operators see rain and water depth across the city as a storm arrives. Underpasses are closed when depth crosses the threshold, crews clear blocked culverts, and the authority issues warnings through its own channels. Every event is reviewed afterwards with the record.

13. From order to operation · Maintain

    Check after every storm

    After each storm, points are checked for debris and damage; references are rechecked yearly and after road works; batteries are changed on plan. Every change is recorded, so thresholds stay true to the street. Sensors damaged in a flood are replaced first, because the next storm may come soon.

    Book field services

14. Data products

    For operators, crews and planners

    City operations and road authorities receive depth alarms; meteorological services and engineers receive rain intensity; drainage teams receive culvert and stream levels; flood risk planners and insurers receive event records. Each product carries its reference and siting. Event records are kept for the review after every storm.

    See the data products

15. Evidence

    Every storm reviewed

    Every reading, alarm, closure and warning is signed and kept. Measurements follow WMO practice, flood management follows the floods directive, warnings follow the multi-hazard early warning checklist and travel in the Common Alerting Protocol, so each event can be reviewed and thresholds improved.

    Drawn against

    WMO-No. 8 · Directive 2007/60/EC · WMO early warning checklist · Common Alerting Protocol

16. What you get

    Hydrometeorological and flood observing networks

    Stream gauges, rain gauges, weather radar and automatic weather stations built to WMO practice, reporting through WIS 2.0 where the agency requires it. Delivered as hardware + software, managed service and build-operate-transfer, for national meteorological and hydrological services, river-basin agencies, utilities.

    Talk to sales

17. Next step

    Plan flash and urban floods with us

    Tell us the site, the measurements and the rules it answers to. We reply with a survey proposal, a design and a scope for flash and urban floods. An engineer replies with a survey proposal and a scope, and the plan grows from one site to the network you need, at your pace.

    Plan a deploymentOpen the Station BuilderOpen the Studio

01The place and its hazards

Where it runs, and what can go wrong.

Operating contextIntense rain on steep small catchments and on paved cities floods streets, underpasses and streams within minutes, faster than river forecasting can follow. Cities, road authorities and emergency services close roads, open drains and warn people, and flood risk plans set out who does what.

Hazards

• Underpasses and streets flooding within minutes
• Vehicles and people swept away in small streams
• Blocked culverts and drains
• Sensor loss in the flood itself
• Warnings that arrive after the water

02What must be measured

What, where, how often, and under which rules.

Each measurement names where it is taken, how often, and the public standard or regulation behind it. Numbers in the sources column open the cited source below.

03The observation stack

From one base unit to a network.

The same blocks at every scale: instruments and a base node, a site with its radio, a fleet run as one, and a network federated on the open protocol.

1. 01

   Base unit

   A flood point: a depth or level sensor on a LoRaWAN endpoint that signs every value, on a street pole above the water.

   Build a station →
2. 02

   Site

   A district: flood points, rain gauges and a gateway on a high building with a cellular link.

   Plan a site →
3. 03

   Fleet

   Every flood point of a city run as one fleet, with one record.

   Managed offers →
4. 04

   Network

   Cities, road authorities, emergency services and meteorological services exchange levels and warnings through open standards.

   The open protocol →

• 01Water level gauge
• 02Compact weather station
• 03LPWAN endpoint
• 04LoRaWAN gateway
• 05Cellular modem/router
• 06Battery case
• 07Pole

Radio and links

LoRaWAN

Battery sensors on street poles reach a gateway on a high building, with no cabling and years on a battery.

Radio and links

Public cellular

Gateways reach the operations centre over cellular, with a second operator where the city requires it.

Radio and links

Satellite

A satellite path at the operations centre’s gateway keeps alarms moving when terrestrial networks fail.

Edge computeEach sensor reports faster when water appears; the gateway’s node compares depths with thresholds set by the city and raises alarms with images at once.

PowerFlood points run on long-life batteries; gateways on building power with a battery.

04How it works

From the instrument to the product.

One observation’s path, tier by tier, with the interface on every link and a bill of materials below; then how the one node grows to a site, a fleet and federated networks.

05From order to operation

Every step, from the first call to a running site.

The same crew and the same record carry the work from scope to maintenance.

1. 01 Order

   Scope the flood points and the warning

   The scope reads the flood risk plan, the history of flooded streets and underpasses, existing gauges and the city’s warning procedures. Nexus Observatory Inc. returns the flood point plan, the radio design, the integration with operations and warning systems and a price per point and per service. 2

2. 02 Survey

   Walk the low points

   Crews walk known flood points with the city’s engineers: underpasses, dips, culvert inlets and streams. They choose poles above the highest recorded water, check gateway coverage from high buildings and note where cameras can see the water without filming homes.

3. 03 Permits

   Poles, streets and privacy

   Sensors on street poles need the owner’s consent; cameras follow the city’s privacy rules. Warning roles are agreed in writing, so the authority that warns decides. Every consent is kept with the point it covers. Residents near cameras are told what is measured and why.

4. 04 Build

   Build for the street

   Depth and level sensors, endpoints, gauges and gateways are built, tested together and enrolled with their identities. Thresholds come from the city’s warning plan, and every part is labelled with the street and the point it serves. Spares are kept at the depot for quick swaps after storms.

5. 05 Install

   Install between storms

   Crews mount sensors on poles above the flood level and set their reference to the road surface, install rain gauges on rooftops clear of obstructions and gateways on high buildings. Every point is photographed and located for the record. Each sensor’s height above the road is measured and kept. 1

6. 06 Commission

   Test thresholds with the city

   Each endpoint proves its identity. Depth readings are checked against a measured reference, rain gauges with a measured volume, and alarms are tested to the operations centre and the warning authority with a staged threshold crossing. Each point joins the live map only when its checks pass. 4

7. 07 Operate

   Close, clear and warn on evidence

   Operators see rain and water depth across the city as a storm arrives. Underpasses are closed when depth crosses the threshold, crews clear blocked culverts, and the authority issues warnings through its own channels. Every event is reviewed afterwards with the record. 5

8. 08 Maintain

   Check after every storm

   After each storm, points are checked for debris and damage; references are rechecked yearly and after road works; batteries are changed on plan. Every change is recorded, so thresholds stay true to the street. Sensors damaged in a flood are replaced first, because the next storm may come soon.

06Data products and integration

What it delivers, to whom, and into which systems.

Data products

• Street and underpass depth alarmsCity operations and road authorities
• Rain intensity across the cityMeteorological services and engineers
• Culvert and stream levelsDrainage teams
• Event recordsFlood risk planners and insurers

Integration

• City operationsAlarms with images reach the operations centre’s screens and road closure procedures.
• Warning systemsThe authority issues warnings in the Common Alerting Protocol from its own system.
• Drainage asset managementCulvert events open work orders for clearing.

Exchanged through Common Alerting Protocol, OGC SensorThings API, LoRaWAN.

07Questions buyers ask

Before you scope it.

Who warns the public?

The warning authority, through its own channels; the network supplies the evidence.

Will sensors survive the flood?

They are mounted above recorded water and keep their data through any lost link.

Do cameras film people?

Cameras are aimed at the water and follow the city’s privacy rules.

How fast are alarms?

Sensors report faster as water rises, and alarms are raised by the gateway at once.

08Resources

The sources behind this page.

Public standards, regulations and guidance, cited where they apply. Each applies only where its jurisdiction or scope does.

1. 1Guide to Instruments and Methods of Observation (WMO-No. 8)World Meteorological Organization
2. 2Directive 2007/60/EC on the assessment and management of flood risksEuropean Union · 2007
3. 3Guide to Hydrological Practices (WMO-No. 168)World Meteorological Organization
4. 4Common Alerting Protocol Version 1.2OASIS
5. 5Multi-hazard Early Warning Systems: A ChecklistWorld Meteorological Organization · 2018

09Related

Use cases and solutions.

10Public safety: specialized fields

Other fields of this industry.

Bring us the site.

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