Local flood alert system, a complement to watershed monitoring tools

Euskalmet classified November 2021 as the rainiest month of the 21st century in the northwest of Euskadi. These heavy rainfall events resulted in an increased river flow and flooding in various areas.

One of the affected areas was the neighborhood of Zorroza in Bilbao, where the tunnel on Clara Campoamor Street was flooded, impacting a dozen parked vehicles. This location is prone to flooding as it is at the same level as the Nervion River estuary and is affected by tides, being in close proximity to the Kadagua River. However, emergency services were quickly deployed once the incident was reported, and within a few hours, the water was pumped out.

Now, would the consequences have been less severe if the tunnel had a local flood alert system in place?

Hydrological prediction and alert systems, a fundamental tool for protecting cities

Urban areas, as highlighted by the Food and Agriculture Organization (FAO) of the United Nations, cover less than 0.5% of the Earth’s surface. However, they currently concentrate over 55% of the world’s population. Projections indicate that this percentage will increase to 68% by the year 2050.

When coupled with the fact that cities have contributed to changes in land use, altering natural drainage patterns and extensively sealing surfaces, it is undeniable that events such as flooding can pose a serious problem.

One of the main “weapons” to address this threat is hydrological prediction and alert systems. These solutions rely on data from flow measurement stations, hydro-meteorological monitoring networks, satellites, and more. Their contribution is essential. In fact, thanks to advancements in recent decades, floods, while still causing significant economic losses, no longer claim as many lives as they used to. The functioning of these systems allows for the activation of emergency protocols and the prompt mobilization of necessary resources to respond to potential flooding events. Some examples of such systems include UHATE, managed by the Basque Water Agency (URA), and INUNCAT, which coordinates flood response in Catalonia.

Hydrometeorological monitoring station network of Euskadi. Source: Basque Government / GeoEuskadi.

Urban floods: Identifying critical and problematic areas

In the previous section, we have made it clear about the usefulness of surveillance systems with their current scope. However, are these tools sufficient?

Given the context of climate change where precipitation patterns are frequently altered, Arantec believes it is necessary to advance towards local flood alert systems that complement existing systems and provide more detailed information. We believe that monitoring critical or potentially problematic areas can be key to increasing resilience against urban floods. In this way, affected citizens can have more information to make decisions such as moving their vehicles to safer areas.

These areas consist of locations that are prone to flooding due to factors such as their location, characteristics of the surrounding terrain, or soil drainage capacity. A typical example would be tunnels. However, we can also include other types of infrastructure such as bridges or stormwater collection systems that may be unable to handle large volumes of water, creating stagnant pools that hinder traffic.

The identification of these problematic areas can be done in various ways. Kansal, Osheen & Tyagi (1), for example, propose the following methodology:

  • Digitization of the drainage network in the study area.
  • Identification of key locations based on their drainage capacity and importance.
  • Collection of precipitation data.
  • Evaluation of runoff.
  • Identification of critical points.
  • Analysis of the vulnerability of critical points in terms of impact (social, economic, and environmental consequences).
  • Prioritization of critical points.

    As can be seen, defining these areas is crucial for deploying an efficient monitoring network and focusing attention on the areas that require the most attention.

    Local flood alert systems, street-level technology

    This is not the first time we have shown you the benefits of early warning systems, and it won’t be the last. In fact, we have no doubt that installations like Smarty River provide the solution to monitor those critical points that may escape current monitoring systems.

    These non-structural local flood alert solutions are gaining more supporters as events like flash floods sow uncertainty and unease.

    The technologies used by these systems vary, although the most common ones are ultrasound and radar-based, which are employed in the solution we installed on the Garonne River. However, radar techniques have been gaining ground in recent years, as they offer high reliability and require minimal maintenance.

    [pdf-embedder url=”https://www.arantec.com/wp-content/uploads/2017/12/SP69.-Radar-nivel-agua.pdf”]

    These equipment can also be equipped with cameras that provide real-time vision of the monitored area’s conditions, which can be of great assistance.

    What strengths do solutions like Smarty River offer?

    Our Smarty River local flood alert system, in addition to providing comprehensive hydrometeorological monitoring consisting of sensors, wireless communication, and a cloud-based management, prediction, and modeling platform, has the following strengths:

    • Easy installation (plug & play) without the need for any civil works
    • Built with open-source standards that allow data exchange and integration with third-party systems
    • Excellent cost-benefit ratio
    • Flexible wireless communications (3G/4G, LoRaWAN, Wi-Fi, etc.)
    • Autonomous operation with solar power supply
    • Resilient equipment designed for harsh conditions
    • Low maintenance requirements


    Urban areas are compelled to adapt to an increasingly extreme climate, manifested through phenomena such as floods.

    Advancing and utilizing technologies that provide a comprehensive understanding of river, stream, or critical point conditions is therefore essential. Local flood alert solutions are undoubtedly part of the answer.

    Sources consulted

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