Strategies to tackle water shortages

View of the Besòs riverbed, from the Molinet bridge. © Imatges Barcelona / Àlex Losada

As the well-known song by Raimon goes, “in my country rain doesn’t know how to rain: it either rains too little or it rains too much; if it rains too little, it’s a drought; if it rains too much, it’s a disaster (...)”. The spell of drought we have seen this year is a characteristic and common occurrence in Mediterranean areas. Climate change and the delay in investments in reuse and desalination infrastructures have exacerbated the situation we are facing this year.

Water scarcity constitutes both a global and local problem, particularly in big cities and their surrounding areas. It has worsened in recent decades as a result of climate change, rampant urbanisation, population growth and social inequalities. In fact, one third of the world’s population is affected by spells of annual drought that hit the poorest and most vulnerable people hardest.

A study recently published in Nature Sustainability shows how the climate crisis and the lack of rainfall have triggered a drought alert in eighty cities around the world, including Barcelona. The study, which focuses on Cape Town (South Africa), reveals the existence of a water divide in big cities. In this particular city, the richest households represent less than 14% of the population and consume more than 51% of the city’s water resources. In contrast, low-income households account for 62% of the population and use 27% of the available water in the metropolis.

Just as postcode is a noteworthy factor when it comes to health, it is too when it comes to water consumption: urban elites consume more water for personal leisure. In the case of Barcelona, for example, in Sarrià - Sant Gervasi, the district with the highest per capita income, average domestic consumption is 128 litres per person per day. In Nou Barris, the lowest income district, it is 92 litres. These figures are largely explained by the water footprint of activities such as watering private gardens or filling swimming pools in more affluent households.

However, Barcelona is one of the European cities in Europe with the lowest water consumption: approximately 106 litres per person per day. There are two explanations for this. Firstly, blocks of flats are the typical type of housing in Barcelona, where, despite the high population density, water consumption is not as high as in other residential models. Secondly, the great drought of 2008 had a profound impact on citizen awareness: a certain water conservation culture has been consolidated. The pricing policy – the price per litre of water increases the more litres we consume – has also played a part.

Supply of reclaimed water to the Llobregat River. © Agència Catalana de l’Aigua Supply of reclaimed water to the Llobregat River. © Agència Catalana de l’Aigua

However, there is still room for improvement to achieve Barcelona City Council’s consumption target of less than 100 litres per person per day by 2030. Improving household efficiency, by installing grey water systems or using drinking water just for drinking and not for other municipal uses, would reduce consumption to below 100 litres in the medium term. In fact, in Barcelona, 80% of street cleaning is carried out with groundwater, which is also used to water green areas and to fill ornamental fountains. The city as a whole has roughly thirty groundwater tanks, distributed over a network of 78 kilometres, which the municipal services use for these tasks.

In terms of drinking water, Barcelona’s total consumption in 2021 amounted to 88.04 hm3 (since 1999, it has fallen by 26.4 hm3). Domestic consumption accounted for 72%, industry and commerce for 22% and municipal services for 6%.

Barcelona and its metropolitan area, at least, have a water-saving culture, but in the current climate scenario, it may not be enough to guarantee future water supply, which would force the government to adopt radical measures. The meteorological drought in recent months is not a new occurrence, and it will recur. It is worth recalling the dry spells of 2000, 2005 and, in particular, the aforementioned drought of 2008. The onset of drought in 2012 and 2018 did not ultimately put the system in a worrying situation, but it did point to a rise in this type of event, such as the one we have experienced this year.

What is the reason for the growing scarcity of water and the fact that droughts are more common in our environment, beyond the characteristics of the Mediterranean climate that Raimon mentions? Is climate change the main cause of the worsening of drought occurrences, or has the Government of Catalonia not done its part when it needed to? Well, both.

Climate change and forest management

Anthropocentric climate change is leading to a rise in global temperatures, more acute in the Mediterranean, according to climate models. Whether it rains more or less, the rise in temperature affects the evapotranspiration of forests and, therefore, determines the rainwater that ends up in rivers. In the case of Catalonia, the huge growth in forest surface area due to the loss, in recent years, of the land devoted to crops and pastures, as well as the lack of management of these forests – more than 80% are in private hands – leads to high levels of evapotranspiration, which is the sum of evaporation and plant transpiration from the surface of the soil to the earth’s atmosphere. Evapotranspiration is central to the water cycle. Therefore, the condition of Catalonia’s wooded area partly explains the hydrological drought of its rivers. If forest management is not improved to facilitate the infiltration of rainwater into aquifers, Mediterranean rivers will end up running dry in the future.

Aerial view of the El Prat de Llobregat desalination plant. © Agència Catalana de l’Aigua Aerial view of the El Prat de Llobregat desalination plant. © Agència Catalana de l’Aigua

The expansion of the forest mass in recent decades and urban growth that ignores the scarcity of water resources and the dynamics of natural systems exacerbate the climate emergency. In the lower stretch of the Llobregat River alone there are currently more than a hundred new urban development projects. This combination of factors, as indicated in the Strategic Plan for Barcelona Metropolitan Area’s Integral Water Cycle (2023), foresees a 12% reduction in surface water resources and a 9% reduction in groundwater resources in the metropolitan area by 2050.

Climate change is also affecting mountain glaciers: studies reveal that all glaciers in the Pyrenees will have disappeared by 2050. And, without snow, reservoirs will see a drop in water. Therefore, according to the data reported by science, we are heading towards a scenario of declining and highly variable availability of water resources.

The shift in water culture

The approach to water management policies changed at the outset of the 21st century. The traditional model consisted of delivering water to any location, satisfying demand without regard for environmental objectives, planning without listening to citizens, based on a philosophy of supposedly technical enlightened despotism.

Warnings about the effects of climate change, the conflict over the Ebro water transfer project and the European Union’s Water Framework Directive (2000) changed the ground rules. The new approach to this issue focused on water demand management and rational water consumption, on the achievement of a satisfactory ecological status of water systems, and on citizen participation in decision-making.

In 2003, Catalonia’s water management policies underwent a radical change. The Ministry of the Environment and Housing, under Catalan Minister Salvador Milà, commissioned the study Aigua i canvi climàtic (Water and Climate Change), coordinated by Narcís Prat and Andreu Manzano, with the participation of the country’s leading experts. The study accurately foresaw the impacts that we have subsequently witnessed.

In 2009, the Catalan Ministry and the Catalan Water Agency (ACA) approved the Catalan Water Management Plan, which specified the measures and investments to be executed to guarantee the supply and ecological quality of bodies of water. However, the crisis hit and cutbacks ensued, and the plan ran dry, lacking the envisaged resources. Thus, between 2009 and 2017, the necessary investments to cope with drought scenarios such as the current one were not made. Therefore, the water cycle management policy in Catalonia is almost a decade behind schedule. And now we are suffering the consequences, although investments were resumed in 2017. The ACA has planned an investment of 2.4 billion between now and 2027 to adapt to new periods of scarcity and drought. Also in place is the River Basin District Management Plan for Catalonia, which was set in motion in response to this situation we are facing this year.

Strategies to address water scarcity

In light of the growing scarcity of water, the strategy is to become increasingly less dependent on rainwater and to focus efforts on technological investments and a water-saving culture. The ACA, Barcelona’s various authorities and the metropolitan area are clearly committed to this strategy. Today, 58% of the water resources consumed by Barcelona is generated from desalination or reuse, while 42% comes from rivers and wells, a percentage that will have to be reduced, partly as a result of the effects of and adaptation to climate change.

In terms of desalination, Catalonia is equipped with plants in El Prat de Llobregat and La Tordera, which are instrumental in tackling the current drought. In the coming years, La Tordera plant is due to be extended and a new one is to be built in the Foix basin, which would already be up and running had it not been for the cuts made in 2009. This technology has been used sparingly, given the high energy costs involved.

Reuse is the great hope for the future. In Catalonia, 490 hm3/year are discharged into the sea, i.e. 15,770 litres per second, produced by wastewater treatment plants. There is therefore a long road ahead, while taking the limitations laid down by legislation in the health and environmental domains into account. There are inspiring initiatives, such as the one in the city of Singapore, where treated water is fed directly, like drinking water, into the distribution network. In fact, in recent months, the reclaimed water from the Llobregat plant, which can reuse up to 2,000 litres per second, has been used to feed the final stretch of the river, for agricultural uses and, more recently, to supply the metropolitan area.

The major project planned, which is strategic for guaranteeing supply in the metropolitan area, is to regenerate the water from the Besòs River, replicating the initiative being implemented in the Llobregat River. The Government of Catalonia also plans to build 25 reclaimed water production stations in the internal basins. Wastewater treatment systems in buildings and households, as well as rainwater collection facilities, would also constitute an effective water reduction and reuse strategy.

Individual actions within the home are also crucial: during the 2008 crisis, they led to savings of 20%. In addition, reclaimed water is a great opportunity for industries, which, in recent years, have already undertaken efforts to reduce their water consumption.

Supplying water to cities and towns has always proven to be a challenge. The Greeks invented wells, cisterns and fountains. The Romans were trailblazers in water transport and invented arched aqueducts. Innovation and technology have meant that we can turn on the tap at home and water comes out. If we want to guarantee future supplies, we must invest in technology – desalination and regeneration – but still be mindful of the fact that water is a scarce resource. We can preserve wellbeing without over-consuming resources. The alternative is that the water scarcity will drown us.

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