The final conclusions of the LIFE MEDACC project, conducted by the Catalan Office for Climate Change (OCCC) of the Ministry of Territory and Sustainability, CREAF, IPE-CSIC and IRTA, draw attention to the need to adapt forest, agriculture and water management strategies to the new arid conditions expected as a result of climate change. Since 1973, the water flow at the headwaters of the Muga and Ter rivers has dropped by almost half, and the volume of the middle and lower sections of the Segre has decreased by as much as 60%.

The LIFE MEDACC project has come to an end after five years, during which three Catalan river basins were analysed:  the Muga, the Segre and the Ter. The final results and the strategies that must be undertaken to prepare the Mediterranean for climate change will be presented on 24 April in Barcelona. And Catalonia still has a long way to go.

A barely acceptable starting point

In 2014, the Catalan Office for Climate Change (OCCC) established a global indicator of climate change adaptation for Catalonia. The result was barely a pass: the rating was just five out of 10. The OCCC’s working methodology was subsequently adapted as part of the LIFE MEDACC project, and 22 indicators were used to quantify the degree of adaptation in agriculture, water management and forests. Gabriel Borràs, head of the OCCC, the body that coordinated the project along with CREAF, explained, “Of the three basins, the Ter basin was found to be most resilient in terms of the three aspects analysed, especially following the agreement reached in the summer of 2017 with the Taula del Ter. The state of the Muga basin is highly worrying in terms of water management, especially in the summer, and there are concerns for the Segre basin in terms of agriculture, which requires a thorough reassessment”. The model predictions carried out by the Pyrenean Ecology Institute (IPE-CSIC) revealed a positive relationship between forest management and water flow in the rivers of the three basins: “The different projections for the year 2050 show that the reductions in river flow can be minimized if adaptive forest management is carried out. Therefore, forestry policies are hugely important in the field of water management.”.

REDUCED AVAILABILITY OF WATER: LET’S REVIEW AND REBUILD THE MANAGEMENT STRATEGY 

Water is becoming scarcer, not only in the three basins, but throughout the Mediterranean. The LIFE MEDACC project has confirmed a reduction in rainfall, especially in summer, with more frequent and intense droughts and increased evaporation of water into the atmosphere.

The three basins analysed have seen reductions in river flow, a trend that is set to continue in the future if measures are not implemented. However, each of the basins has its own special features that should be highlighted separately.

The Muga: high water demand in summer that cannot be remedied with the enlargement of the Boadella reservoir

The Muga has the smallest basin (just 758 km²), but it presents the greatest concern, since it is the most vulnerable of the three. Between 1973 and 2013, summer rainfall decreased by 60% and the water flow at the headwaters was nearly halved. This was caused by a drier, more arid climate, as well as land use changes.

“A detailed study of the relationship between forest growth and flow reduction in Mediterranean rivers such as the Muga is required”, explained Sergio Vicente-Serrano, a researcher at IPE-CSIC..

The basin has very high water demand pressures in summer due to the major influx of tourism in coastal areas and irrigation campaigns. According to Javier Zabalza, a researcher at IPE-CSIC, “The simulations that were run as part of the project show that the solution definitely does not lie in the proposed enlargement of the Boadella reservoir in Darnius”. In fact, the findings show that there is no management strategy to ensure that future demands are met and environmental flows are guaranteed.

Gabriel Borràs went on to say, “Efforts must focus on reducing water demand, improving water-use efficiency and implementing desalination plants and wastewater treatment plants on the coast. The tourism sector must be willing to invest in such infrastructure if it wants to keep visitor numbers strong”. Recharging local aquifers is another adaptation measure to be implemented and improved to address the high vulnerability of the Muga basin.

Reducing water transfer to Barcelona in the Ter basin is a priority

The studies carried out as part of the LIFE MEDACC project show that a reduction in the volume of water transferred from the Ter to Barcelona would result in major improvements in the river’s flow.

The Ter has seen a flow reduction of almost 42% at its headwaters and 66% in its lower section since 1971. Again, these have been caused by the drier climate, land use changes and, above all, the large amount of water transferred to the Metropolitan Area of Barcelona. These situations must be remedied soon to minimize the reduction in water flow in the future.

This would involve fully deploying existing desalination plants, an effective solution for this basin.

In this regard, the LIFE MEDACC project considers it extremely positive that the volume of water transferred from the Ter to the Metropolitan Area of Barcelona during the first quarter of 2018 was 27.5 hm³, a historical low according to the Catalan Water Agency. This figure, which was achieved within the framework of the Taula del Ter, has given rise to a series of measures to gradually reduce the water transfer from the Ter to Barcelona by almost 50% over the next 10 years, thereby enhancing the river’s environmental flows and restoring it to good ecological status.

In the Segre, water concessions need to be redefined and the Segarra-Garrigues canal reassessed

The Segre basin presents some distinctive, well-known features. It is the largest basin (13,000 km²) and is greatly affected by agriculture. The construction of the Segarra-Garrigues canal is having an impact on the management strategy to be followed. Projections indicate that it is unlikely that current agricultural production can be maintained. For this reason, the project proposes a series of measures to reconsider water management and usage in the Segre basin.

On the one hand, the volume of water required in the Segarra-Garrigues canal must be revised. If the volume anticipated in the approved concession of 342 hm³/year goes ahead, the Camarasa and Rialb reservoirs will be affected. In fact, the Rialb reservoir could be empty for one month a year by 2027. “It is also absolutely essential to redefine water concessions for irrigation and adjust them to needs and actual availability: what needs to be irrigated, who needs the water and why?” said Borràs.

In addition, it is important to bear in mind that the environmental flow regime in the Segre basin is also largely determined by the water management strategies used by hydroelectric plants at the headwaters of rivers. “It is imperative to align the environmental flow of rivers, the needs of agriculture and the interests of hydroelectric plants”, said Gemma Cantos, a technician at the OCCC.

LET’S MANAGE OUR FORESTS TO COPE WITH DROUGHTS

With respect to forests, a similar trend affects all three basins. As seen across Catalonia, forest cover has increased at the expense of crops and scrubland. In the Muga basin, which has undergone the most extreme change, forest cover has grown by 20% in just 35 years (from 1970 to 2005). These new forests are very dense and usually unmanaged, a situation that leads to strong competition for water. In fact, the results show that these forests are increasingly vulnerable to droughts and fires, especially in the Muga basin.

If this trend continues, the forests in the three basins, and in Catalonia in general, will face a greater fire risk and become more vulnerable to droughts, infestations and other disturbances. “In the Muga basin, for example, the number of days a year with an extreme risk of fire will double in some areas”, said Eduard Pla, a researcher at CREAF. In addition, some plant species will not be able to withstand the increasingly intense and frequent droughts and will be replaced by more drought-tolerant species. All this will reduce the productivity and carbon-storage capacity of forests, especially those located in wetlands. However, according to the model predictions carried out in the three basins, proper forest management can help minimize reductions in river flows.

To reduce this tendency, the LIFE MEDACC project tested a series of forest management measures, which could easily be extrapolated to other Mediterranean forests, to improve their capacity to withstand severe drought conditions. The results are clear: “Forest management has substantially reduced the risk of fire and tree death caused by the summer droughts of 2016 and 2017. This effect was particularly pronounced in the holm oak forests of the Muga basin, the red pine forests of the Ter basin and, to a lesser extent, the pine forests of the Segre basin. On the other hand, in areas where no action was taken, forests have suffered from more tree death and the risk of fire has risen in all three basins due to the water shortage”, explained Diana Pascual, a researcher at CREAF.

LET’S IRRIGATE BETTER, OPTIMIZE CROPS AND MANAGE DRYLANDS

As with forests, agriculture presents similar trends across all three basins and throughout Catalonia. Firstly, phenological changes were detected in the crops of the three basins. For example, some crops, such as apple trees, were found to start their phenological activity early due to the high temperatures in winter and spring; in addition, their flowering was jeopardized due to the lack of cold weather, and the quality of the fruit was affected by heat waves.

Secondly, the reduction in rainfall and increased water demand have led to a decrease in water availability in terms of both quantity and quality; this is particularly pronounced in the coastal plains of the Muga and the Ter. This makes it crucial to adapt crops, especially given that 70% of Catalonia’s crops are grown using dryland farming techniques, and to improve water usage. “It will be essential to choose the most drought-resistant species and varieties, apply crop rotation and fallow methods, and adopt more sustainable farming systems”, noted Robert Savé, an IRTA researcher who led the part of the project related to agriculture.

Although these are broad trends, the predominant crop grown in each area is different. The Segre is the only basin included in the study where vine growing is prominent. In this case, the project tested and proved that, based on the irrigation system used, which involves mulching (a technique in which the soil is covered with a layer of organic or plastic material to reduce erosion and retain more water), vines grow better despite increased water use efficiency.

Some vine varieties can be grown at higher altitudes, and although this would lead to production losses, they would be offset by the organoleptic properties of the wines produced.

In the Muga and Ter basins, substantial water savings have been achieved in maize fields and apple trees by following recommendations for the amount of irrigation water required at each stage, starting from the crop growth phase, and monitoring weekly weather forecasts and information obtained from humidity sensors installed in the fields. These savings were achieved thanks to studies carried out by IRTA – Mas Badia (GIROREG) on different current and potential future crops that analysed water needs and seasonality due to phenological changes. “Farmers who have followed the irrigation recommendations of the GIROREG system have managed to reduce the amount of water used for maize by 20% to 30%. In addition, the economic profitability of the apple orchards was 4.2% higher than those in which traditional farming criteria were applied”, explained Francesc Camps and Inma Funes from IRTA. “We have a serious problem, because the current water management framework does not encourage savings. Efforts are needed to integrate different strategies that involve as many stakeholders as possible (farmers, technicians, irrigation communities, land planners, etc.) with a view to managing water efficiently and sustainably”, added Carme Biel and Xavier Aranda, researchers at IRTA.

A PARTICIPATORY PROCESS: LET’S GET INVOLVED

During project development, a permanent network of local stakeholders involved in the three river basins and cross-cutting stakeholders from throughout the territory was set up to work alongside those responsible for the project. This meant that the teamwork was multidisciplinary at all times and took the needs and interests of the river basins into account. During the regular meetings held, stakeholders from government, natural areas, businesses, agriculture, NGOs, universities and research centres, as well as citizens, worked together.

One of the objectives of these participatory activities was to develop action plans in the three basins agreed by all stakeholders. The other goals were to decide where to carry out pilot forest management tests, to identify the adaptation measures and initiatives already under way in the territory (improvements in irrigation, forest-related measures to make forests more resistant to fire, etc.), and to decide on new measures to be implemented. This collaborative work led to a series of recommendations to generate changes in the development and application of climate change adaptation policies.

This project was led by the Catalan Office for Climate Change (OCCC) and coordinated by CREAF. It also benefited from the participation of two partners: IRTA and the Pyrenean Ecology Institute (IPE-CSIC)

Informative report of the project (in Catalan):  http://www.creaf.uab.cat/fotosprensa/medacc.pdf