Lorca Case study

Lorca and tools to map risk and information flow in flood emergencies

The Lorca case study aims to improve the internal capacity in the dissemination of crucial information during disaster events. In particular the focus is on how culture can become an asset to enhance a more efficient and wider transmission of information and thus improve disaster risk reduction to extreme events such as earthquakes, forest fires near populated areas or flash floods. Another key aim is raising awareness of the potential benefits of incorporating culture in DRR, especially focusing on regional and local authorities, as well as emergency practitioners and land and water use planners. Regarding both aims, the Lorca case study plans to investigate the potential benefits for strengthening and increased utilization of the socio-cultural networks and also focuses on better understanding of the dynamic nature of socio-cultural networks, making it useful in the different phases of DRR.

Introduction to Lorca and information flow during flash flood extreme events

The case study will take place over an area covering the administrative boundaries (see figure 1) of two municipalities: Lorca (91,759 inhabitants, as of 2014) and Puerto Lumbreras (14,742; as of 2012). For practical issues, hereon we will refer to the case study as Lorca case study. Settlements in Lorca have been identified coming from 5,000 years ago. It was a Roman city and even gained importance during the Middle Ages, first under Muslim occupation and later as a defence frontier between Christians and Muslims. Thus, it possesses a valuable historic heritage, with Lorca castle arising as the most notable landmark.

Figure 1: Location of the cities of Lorca and Puerto Lumbreras within Murcia region in South-East Spain

Lorca is the third city within Murcia region and the main one in the shire of Alto Guadalentín, a large valley which has turned into one of the most important agricultural areas in Spain. Paradoxically, the area characterises by a semi-arid climate. Indeed, the Guadalentín river was named after the Arabic words “mud river”. In fact, agriculture heavily depends on groundwater abstractions and water diverted from the neighbour Tagus river basin. The livestock sector is also very relevant in this area, in particular pig breeding.
The area has historically suffered serious disaster episodes. A major one was the flooding of town in 1802 as a consequence of the collapse of the walls of the main water reservoir of the city, with casualties estimated at over 700 people. The area also has historically faced recurrent droughts, even forcing massive migration episodes due to famine. More recently, on May 2011, the town was struck and seriously damaged by an earthquake with a magnitude of 5.1o in Richter scale, with an epicentre so close to the surface that made it equivalent to an 8o normal earthquake, which killed 9 people.

A very relevant issue regarding EDUCEN is social structure of the population. In the past 15 years, the area has experienced a very significant population growth, mainly because of immigration of rural workers mainly coming from Morocco and Ecuador. In addition the population of European retired people, who come to live to the area after retirement attracted by the nice weather and lifestyle, has become significant. The foreign population is estimated as a 20% of total, with a strong bias of male population (the male population is a 50% higher than female).

Lorca area is affected by large climatic contrasts: it suffers frequent droughts, but also torrential rains which provoke recurrent floods; very high temperatures happen along the summer and heavy frosts are usual in winter.

In example, the study area -i.e. administrative municipalities of Lorca and Puerto Lumbreras- has been recently affected by several disaster events, which constitute a relevant sample of the high exposure of this region to catastrophes:

  • In 2011, it was struck by one of the most intense earthquakes produced in Spain in the last decades
  • In 2012, an especially intense flash flood episode happened which also caused flooding in some areas for several weeks
  • In 2015, recurrent heat waves hit the area, favouring a forest fire episode which affected low-density populated areas.

The most adequate example to show the rationale of the case study can be the flash flood episode, in particular because of most direct involvement of SEGURA and its value to depict the importance of prompt and effective communication in these episodes.

As shown by the graph of water flow in Nogalte wadi, a tributary to Guadalentín river, and the tow images of figure 2, in less than 20 minutes and due to an extreme event of heavy rain, the situation changed from an dry riverbed to a wide and fast-flowing river.

Figure 2: Flash-flood episode in Puerto Lumbreras (September 2012)

A very illustrative video showing the effects of this combined episode of flash flood and local heavy rain can be watched here: INUNDACIONES LORCA 28 DE SEPTIEMBRE DE 2012

Some lessons were learnt after the internal analysis of this episode:

  1. There is a need to formulate an action protocol between the river basin Authority and local authorities to improve communication in these crisis events in order to bring together in a more efficient manner all parties working on the same issues with a common goal: DRR. Existing protocols can be improved by better definition of ways to approach and communicate with local stakeholders and population concerning warnings, alarms and specific measures. One of the lessons extracted was that the river basin Authority is not adequately involved in emergency planning and management even though this organization produces and holds very valuable information. For example, the Segura river basin Authority manages a system – named SAIH- that takes real time data about rainfall and flows, but this information is not shared in real time.
  2. Immigrants and foreigner tourists were much more affected by the floods. This evidence shows the room for making use of formal/informal networks for an improved flow of information in these or other minority groups. An increased role of soft infrastructure is definitely required for a better preparedness and management of these catastrophes.

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