La Emilia is a small village in the North of Buenos Aires, Argentina. Its location next to the “Arroyo del Medio” river has been subject to several flood alerts throughout its history. In 1966, La Emilia was hit by a massive flood after a period of heavy rain, leaving more than 400 liters per squared meter and causing two deaths. Local authorities suggested the construction of retaining dikes to avoid future flooding.

Unfortunately, these infrastructures were neither high nor strong enough to dam the “Arroyo del Medio” water during the heavy rains of the austral summer of 2017. On the 16^th of January, 75% of the population of La Emilia was forced to evacuate, one person died, and more than 3,000 people were moved to several evacuation centers. The dikes collapsed and flooded the village, creating a “swimming pool effect” that cut off roads and railways for days.

The local government rapidly implemented a plan to manage flooding and prevent future tragedies. Ideally, the best solution was to regulate the flow rate by constructing a dam upstream. This solution was very costly and would have also affected other areas that would be submerged, so it was automatically dismissed. Local authorities finally decided to increase the height of the dikes and implement an early detection and warning system for flood prevention in the river basin.

Rack2, Libelium’s distributor in Argentina, has implemented the early detection and warning system. This corporation has specialized in IT and telecommunications solutions for more than 15 years and is growing interested in the Internet of Things sector. Rack2 offers complete IoT solutions thanks to the combination of its Sense2Cloud software platform with Libelium’s wireless sensor platform technology.

Deployment of the project

Specialists carried out a preliminary study to determine which locations were most relevant for sensors to be installed along the Parana River, from the source to the mouth, with special emphasis on the riverside municipalities.

The main target of this project was the deployment of an early flood detection and warning system, a reliable and stable structure in terms of communications and reading accuracy. The Water Authority of the Province of Buenos Aires required a permanent water monitoring system, not only for risk alerts but also to produce a satisfactory water flow and control and record its behavior.

The Libelium wireless sensor platform has been installed in four different locations to monitor the river:

• La Emilia (Province of Buenos Aires)
• Puente Figueredo (Province of Buenos Aires)
• Conesa (Province of Buenos Aires)
• Peyrano (Province of Santa Fe)

The main parameters to be studied are the river water level and the weather forecast and observation using Waspmote Plug & Sense! Smart Agriculture PRO. For that purpose, four units were installed in the area, including the following sensors:

• Ultrasound sensor.
• Temperature, relative humidity and air pressure.
• Pluviometer.
• Wind speed.
• Wind direction

The ultrasound sensor measures the distance between itself and the surface of water. This sensor is frequently used in similar applications, such as measuring liquid level or detecting presence. The sensor emits ultrasonic waves which rebound in the water and offers the system the distance between the node and the water. The water level of the river can be known by applying simple calculations.

The system included double telecommunication technology base due to the requirements of the area. Rack2 deployed and implemented a private LoRaWAN network as the principal communication protocol for those municipalities where telecommunication infrastructure was not stable enough and 4G as a redundant communication protocol.

The data gathered by the sensors was sent to the Rack2’s Sense2Cloud platform where it can be visualized and analyzed. The Sense2Cloud dashboard allows the end user to check the status of the sensors every 30 minutes and receive warning alerts in case the parameters’ thresholds are exceeded.