Country & City Focus

The retreat of the Llobregat delta

Translation into English of an article from the Taula del Llobregat

The Llobregat delta has retreated 800 metres in a century. A study by the Universitat Politècnica de Catalunya reveals that the width of the river at its mouth was 275 metres in 1846 and is currently 36 metres.

Scientists from the Universitat Politècnica de Catalunya reveal surprising data on the Llobregat river and its delta, in a study published in the journal Natural Hazards and Earth System Sciences. The most significant data is the quantification of the delta's retreat in just over 100 years. Using geolocated historical maps, they determined that the Llobregat delta, at its mouth, retreated 800 metres between 1891 and 2000, before the diversion of the mouth for the expansion of the Port of Barcelona.

These data are relevant because it has never been calculated with this level of precision. "This retreat is very important. We knew that sand was being added to the Llobregat delta because it was retreating, but the extent of this retreat was unknown," explains Arnau Prats, a researcher at the UPC and one of the co-authors of the study.

The scientists started with a hypothesis that was not subsequently confirmed. "The hypothesis we put forward was that infrastructures, civil engineering works, the AVE railway, dams, but above all the motorway and the expressway, were responsible for this modification of the lower course of the Llobregat", explains Carles Ferrer, professor and researcher at the UPC and one of the three authors of the study.

Les universitaires ont eu une surprise : "La voie rapide et l'autoroute ont été construites il y a 50 ans et l'échelle de temps du recul du delta est de plus d'un siècle", souligne Juan P. Martín Vide, également enseignant et chercheur à l'UPC et troisième co-auteur de l'étude. Il fallait donc chercher les causes ailleurs.

The Llobregat lock dams and the erosive action of the sea, main causes of the delta's retreat

The authors of the study consider that the reservoir dams of La Baells, La Llosa del Caballo and Santo Ponç are not the main cause of the delta's retreat because they are located several kilometres from the mouth and "the transport of sediment is slow", according to researcher Arnau Prats. He explains that "the transport of coarse sediments from the bottom of the river can take decades to arrive from Baells to the mouth".

The three authors of the study -Juan P. Martín Vide, Carles Ferrer and Arnau Prats- point to the lock dams as the main cause of the delta's retreat. They were built throughout the 19th century with the aim of exploiting hydraulic energy. These infrastructures, as well as the different channels in the last river section, have reduced the contribution of coarse sediments to Prat de Llobregat, which are the ones that make the delta move forward. In addition, the action of the waves has eroded the land that the river had gained on the sea.

On the other hand, the researchers found that when there is a flood at the headwaters of the river, the marshes reduce the supply of sediment because they reduce the water flow by 20%. And this reduction has an effect on the transport of sand and gravel. "We have found that the reservoir dams cause, on average, a 20% reduction in the peak flow of the Llobregat at the river mouth, and that this 20% reduction leads to a 40% reduction in the transport of sediments from the river. Nevertheless, the impact of this inertia is still limited in the delta. According to Professor Juan P. Martin Vide, the effect "will be more important in a few decades".

Eliminating channelling to reverse the trend

Scientists do not foresee miracle solutions but a change in the trend. "We can't talk about solutions like in other areas of life or engineering, where everything is solved once the remedy is known and applied. Here, we should rather think of changes in trends", explains Juan P. Martín Vide.

They believe that the measures that can be taken will take a long time to become visible. "We have to keep in mind that these lock dams are located several kilometres upstream from the delta. Therefore, any action taken now would take a long time to be noticed," adds Carles Ferrer. He suggests: "In addition to the lock dams, we could also think about the small streams, tributaries, etc. that are channelled through concrete dikes, which also limit the sediment supply to the delta and are closer to the mouth. We could think about removing these channels which, in the long term, could help to increase the sediment supply from the Llobregat to the delta.

The removal of these channels and lock dams is the long-term solution proposed by the study, while the traditional provision of sand on the beaches of the delta is a short-term and ephemeral measure.

The new river mouth, a sediment trap

The Llobregat is one of the rivers that have been intensively exploited since the industrial revolution in Catalonia.

From its source in Castellar de n'Hug to its mouth in Prat de Llobregat, there are 170 kilometres of reservoir dams at La Baells, La Llosa del Caballo and Santo Ponç, as well as numerous lock dams and channels.

In 2004, the diversion of the mouth 2 km further south than the original mouth was inaugurated, due to the expansion of the port of Barcelona. However, the infrastructure did not foresee what would happen to the sediment. "The new mouth is twice as wide as the old one. And this poses a problem for the transport of sediment from the river to the beach. During floods, when there is more sediment transport, the riverbed is wider and the water velocity is therefore lower. As a result, the material transported by the river is trapped at the bottom and reaches the coast less. And this fact is not without consequences: "What happens is that this bottom increases because of the accumulation of sand that comes from upstream and is not deposited on the coast. And this, in the long term, can be a problem because the hydraulic capacity of this channel can decrease due to the rise in the bottom," concludes researcher Arnau Prats.

The "hardest working" river

Since the beginning of the 19th century, the Llobregat River has been equipped with lock dams and channels to supply the textile factories born of the industrial revolution. So much so that the French geographer Pierre Deffontaines (1894-1978) said: "Perhaps no river in the world has been so intensively exploited as the indigent Llobregat".

Sources :

https://beteve.cat/medi-ambient/retroces-delta-riu-llobregat/

https://www.sostenible.cat/reportatge/el-preu-de-la-revolucio-industrial-al-llobregat

Attack on the president of the Kruščica local community is an attack on all activists as well as an attack on the legal and constitutional order of BiH!

Tahira Tibold

The Coalition for the Protection of Rivers of Bosnia and Herzegovina strongly condemns the stoning of the house of Tahira Tibold, president of the Kruščica Local Community and one of the Brave Women of Kruščica, which took place by unknown perpetrators on Wednesday morning, November 25th.

“It is a cowardly attack by people who do not know how to deal with a woman who is not affected by blackmail, bribery or threats. Since she became president of the local community, there has been continuous pressure on her and her family. Hate speech and heinous lies were written on social networks, live threats were subtly made, and now they have switched to physical assault. We must not tolerate violence, this is not just an attack on a woman, a fellow citizen, but also on the legal and constitutional order of BiH, given that Ms. Tibold represents all residents of the Kruščica local community who elected her and gave her legitimacy,” said the Coalition for River Protection.

The attack came after the FBiH government announced it was preparing several regulation amendments that would prevent the negative impact of small hydropower plants to the environment, and after confirming that there would be no subsidy for the construction of these plants after this year.

”This is not the first attack on people who are activists in Kruščica. So far, the police have been silent, but we believe that they are in the service of citizens and will find the perpetrator or perpetrators of this unfortunate attack! We want their names to be revealed and published. I regret the breakdown of interpersonal relations in Kruščica, but small hydroelectric power plants will not be built here for sure!”, said Maida Bilal, president of the Association of Citizens Ecological Society “Bistro” from Kruščica and one of the Brave Women of Kruščica.

Turin : a new stop to the long march towards water remunicipalization

On June 5th, 2020, at the end of a three months “de facto” suspension of constitutional rights, taking advantage of the inability of the Italian citizen to express themselves at the time, a blocking minority of small and medium municipalities of the Turin metropolitan city has rejected the proposal of the city of Turin to remunicipalize SMAT S.p.A. the local water company owned by them but ruled under Italian commercial law as private profit making company, thus stating that water is not a commons but a commodity. As a matter of fact, SMAT tariffs and water bills not only recover full operation and investment costs, but also the return on invested capital, i.e. profit.

The long march of the Italian Water Movement towards implementation of the Referendum of 2011 outcome is stopped once again by a political centre-right coalition led by the Democratic Party, disregarding popular will expressed by 25.609.701 i.e. 96,32% voters, to exclude any profit from water management and provision.

The only way to comply with the pronouncement of Italian people is the transformation of SMAT stock company into a non-profit company governed by public law whose mission is not profit but just the full cost recovery to guarantee to everyone the human right to water and sanitation services.

The Municipality of Naples achieved the former ARIN SpA remunicipalisation into ABC Naples soon after the Referendum of 2011, thus putting the accounts right, improving the quality of water supply and keeping water bills below the national average. Conversely, small and medium municipalities of the Turin metropolitan city, imbued by the mercantile culture of “profit über alles”, have constantly refused to follow the Naples example.

Despite the stop they have presently imposed to water remunicipalization, the Water Movement does not take a step back : it is committed to the coming renovation of local City councils where values and principles of water as a commons could finally prevail.

Forum Italiano dei Movimenti per l’Acqua
Comitato provinciale Acqua Pubblica Torino

http://www.acquabenecomunetorino.org
acquapubblicatorino (at) gmail.com
+39 388 8597492

12 and 13 June 2011: the yeses win the referendum! 9 years have passed or 9 centuries ?

12 and 13 June 2011. Twenty-seven million Italians repeal article 23 bis of Law Decree no. 112 of 2008 which obliged the privatization of public services, including water management.

An act of direct democracy that is immediately put down by the technical government of Prof. Monti, with the assignment of the SII’s management (Integrated Water Service) to ARERA (Market Regulation Authority) which adopts a tariff system with structural profit margins and other protection systems for the private operator that make a big leap forward to the neoliberal policies in Italy, against the popular will.

In June 2020, thanks to the COVID-19 emergency, the rule of law is completely abolished.

The simplest constitutional rights have collapsed: education, justice, health (except for intensive care for COVID-19), restraining the free movement of people, the economy and, of course, collapse of the right to work.

After the lockdown, phase 2 begins, which mainly concerns measures for the reopening of economic and commercial activities, decided after long negotiations with Confindustria, while the implementation of the pandemic plan remains on paper, as well as the exercise of constitutional rights, including the free movement of people which will arrive only in June on the national territory.

Manure pollution from the Osona and Lluçanès springs in 2020

The Grup de Defensa del Ter has been analysing the nitrate concentration in springs located in the counties of Osona and Lluçanès for 19 years and this year the historical record for nitrate concentration was broken in one of these springs. The analysis was made possible thanks to 53 volunteers from the Grup de Defensa del Ter who visited 164 springs, 13 of which were not flowing. The average nitrate concentration was 72 mg/l, while the WHO has set the limit for the drinking water purification at a nitrate concentration of 50 mg/l. The average value this year is slightly lower than in 2019, which was 76 mg/l, although the difference is not significant enough to assume that there has been a real decrease in pollution. We still have almost half of the contaminated springs, about 45%.

The Gana spring in Calldetenes with 492.2 mg/l of nitrates was the most polluted this year, beating the historical record since the beginning of the analyses in 2002, followed by two springs usually on the podium, the Gallisans spring in Santa Cecília de Voltregà, with 465.8 mg/l, and in third place, the Cassanell spring in Taradell, with 344.80 mg/l. Last year, the first prize was awarded to the latter source, with 456.8 mg/l. This year, however, the Gana spring is at nearly 500 mg/l of nitrate, a value 10 times higher than what the WHO allows for the drinking water purification. This is undoubtedly the highest value we have found in 19 years of source analysis.

Read more in Catalan on the website of the Grup de Defensa del Ter

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