10 January 2012

Henny van Lanen: “Drought response capacity and prevention to reduce future Europe's water balance vulnerability”

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Droughts and water scarcity are increasingly being observed in many regions of Europe and, according to the EEA, in the coming decades the continent is likely to suffer more frequent meteorological droughts

Climate change predictions for Europe indicate considerable changes in the water balance throughout the continent, with an increased likelihood for summer droughts in the Mediterranean, Central and South Eastern Europe. Other regions are also likely to experience changes in the annual distribution of precipitation as well as in their energy and water balances, resulting in an increased likelihood for periods with reduced water availability as well as in a generally higher variability and in increased probabilities of extreme climatic events.

Persisting over months or years, droughts can affect large areas and may have serious environmental, social and economic impacts. Among the most affected areas are agriculture, energy, navigation, tourism and health (heat-waves related fatalities).

According to a study performed commonly by the European Commission and Member States, the drought of 2003 in Central and Western Europe was responsible for an estimated economic damage of more than 12 billion euros alone. ‘Fostering European Drought Research and Science-Policy Interfacing’ (EU-FP7 DROUGHT-R&SPI) is a three-year research project. Its goal is to reduce future Europe's vulnerability and risk to drought by combining investigations in six case study areas in water-stressed regions (Greece, Italy, Netherlands, Portugal, Spain and Switzerland)with drought analyses at the pan-European scale. DROUGHT-R&SPI aims at enhancing the understanding of drought as a natural hazard, its process and occurrences, environmental and socio-economic impacts and vulnerabilities, risks and policy responses. It will adopt Science-Policy Interfacing at the various scales and will try to foster a better understanding of past droughts, which will contribute to the assessment of drought hazards and potential vulnerabilities in the 21th century. The work will be linked with the European Drought Centre and with the UNESCO’s International Hydrological Programme so that the outcome will be consolidated beyond the project lifetime. Henny A.J. van Lanen, Associate Professor of Hydrogeology, Chair Group of the Hydrology and Quantitative Water Management, Centre for Water and Climate, Wageningen University (Netherlands) is both the European Drought Center and the project co-ordinator.


There are three kinds of drought. Meteorological (precipitation deficiency) soil water (soil decifiency causing plant water stress, reduced biomass and yield) and hydrological drought (lack of groundwater recharge, lower groundwater storage, lower streamflow). Does the project address the three kinds and is Europe supposed to see an increase also in soil water and hydrological droughts?
Yes, it does address the three. If you have more meteorological drought very likely you will also have soil water drought. Even if it is not directly linked to meteorological drought, depending on the storages very likely you will also have more hydrological drought, that constitute the main reason for the reduced stream flow, which has an impact on the wetlands.

What is the difference between drought and water scarcity?
The main one is that drought is typically the consequence of a natural process linked to climate variability while water scarcity is typically the consequence of human behaviour, that is that people are demanding and using more water than is available.

And between drought and desertification?
Desertification is a process the leads to degradation of land and water, it is closely linked to human activity and can be caused by a strong exploitation of land and water. The link with drought is that if you overexploit your land through too much irrigation for instance, then a drought will trigger the desertification process.

In the project presentation you highlight that vulnerability is context-specific. What is the most important context specific feature of each of the six case study countries?
The Netherlands have a high water demand but a very typical feature, that is that if we have a drought we will have troubles with salt water. It is a low lying country and we need the fresh water from the rivers to push the salt water coming from the North Sea back in the river mouth.

If we have insufficient water in the river Rhine we get too high salt water concentrations in the river mouth and therefore we have troubles with the inlet of fresh river water that is required to flush the polders (reclaimed land below sea level). Surface water levels and groundwater levels in the polders are lower than the sea level, which means that sea water is infiltrating trough the sea bottom into the groundwater system and then is flowing to the polders as groundwater where it ends up in the tube drains and ditches (surface water system) of the polders. If we do not flush the surface water system of the polders with fresh river water, then the salt concentration in the surface systems becomes too high (deterioration of the water quality) and can cause harm for the aquatic ecosystem for example.

Another problem is the cooling water of the energy plants. If we have a drought like the one we had in North Western Europe during last spring and early summer and the rivers continue to dry, the power plants are not allowed anymore to release cooling water into the river, which means they have to use other cooling ways and take energy from other energy plants.

Switzerland is currently not a water-stressed region and for instance the river Rhine even in dry periods usually has a lot of water coming from the snow and glaciers. Nevertheless in the future climate if you have less glaciers and snow melt that will change into a rain water-type of river, which means you will have lower river flows in the summer period, something that could have an impact particularly on European transnational rivers. In Europe, summer river flow comes from stored water (snow melt, glaciers, groundwater bodies, large lakes, bogland). In general, summer rain does not feed the rivers, but it is used for the replenishment of soil moisture and later for evapotranspiration (the sum of evaporation and plant transpiration from the soil to atmosphere) by vegetation/crops. Large, transboundary rivers have a substantial snow (early summer) and glacier component (whole summer). If this component reduces, then their river flow will become lower, which will affect the aquatic environment, but also many economic sectors (e.g. water-born transport, energy, supply of irrigation water for agriculture).

In the Mediterranean there are higher temperatures, which means higher evapotranspiration and therefore higher water demand for irrigation for instance, especially in Spain and in Italy, where the Júcar and the Po are strongly affected by irrigation practices. In Greece we have selected an island that should be representative for a lot of Mediterranean islands since they have troubles with fresh water. They clearly depend on the one coming from rain and of course with the increase in temperatures the evapotranspiration will be higher , which will have a negative impact on agriculture, irrigation and tourism. Another problem is forest-fires, especially in Portugal, a country now clearly above average temperatures and often hit by severe forest-fires, the last one of which was recently reported this fall.

Have you taken into account that the Disaster Risk Reduction measures to identify and implement might need to be gender-sensitive, that is both taking into account women’s specific vulnerabilities (e.g. women are generally not taught how to climb a tree, relevant in case of flood, might not have the same access to information etc) and their contribution to build disaster resilience?
It is interesting that you raise this point because if I go to Asia, Africa or Latin America this is a topic very high in the agenda but it seems not so in Europe. We did not make any distinction between males and females. We know from history that women played a really important role in reducing vulnerability and in building resilience through history, so of course if in the case studies it gets clear women groups and or women’s related activity play a specific role, this will be identified.

The presentation states ‘The project will adopt Science-Policy Interfacing at the various scales, by establishing Case Study Dialogue Fora at detailed scale and a pan-Europe Dialogue Forum at a large scale, which will ensure that the research will be well integrated into the policy-making from the start of the project onwards’. How are you going to do it and what actors will be involved?
We had already started with the Xerochore project (An Exercise to Assess Research Needs and Policy Choices in Areas of Drought, finalized last year, http://www.feem-project.net/xerochore/) but it is particularly in this project where we are producing since the beginning Science Policy Briefs, that is there are scientists trying to understand what politicians need for the decision-making process. The two scales approach is a challenge because in Europe those who really feel the drought are the local people, the farmers, those running tourist businesses, those on the rivers who load less cargo, but on the other hand the European Commission and Parliament need to come out with a legislation. We are really curious to find out how to bring these two different worlds together. The Case Study Dialogue Fora will involve the agricultural sector, tourism, irrigation on a local scale. On the pan-European level we have the first Drought Dialogue Platform meeting planned for next March in Valencia. We will meet the policy-makers, explain them the state of the art and what we can deliver to them and they will tell us what they need for their policy-making and the major vehicle for the policy making in this arena is the European Water Framework Directive. The pan-European forum will also involve the agricultural sector, tourism, navigation and the health sector, linked with the energy one.

What about energy?
Besides the cooling water the other major issue in Europe is hydropower, which in drought might be insufficient. This is particularly true in the Scandinavian countries but also in mountainous regions in Central Europe. Lack of hydropower is caused by lack of water in the reservoirs, which get the water from the rivers that get it from snow melt. If you have a very quick start of the winter and really cold winters, then you immediately have snow, so there can be plenty of water but it has snow. Also, sometimes the snow melt is late, the reservoirs get very low and therefore there is insufficient water to run the power plant, whose turbines are driven by water. This can bring to an energy lack; It is what we call a winter drought.

One of the aims of the project is to lead to ‘a more thorough implementation of the EU Water Framework Directive, particularly by further developing of methodologies for Drought Management Plans at different scales’.

Until now it is voluntary for river basins organizations to include drought in their management plan. This is one of the things we need to work on in the project because there are now a number of countries that have a drought management plan (e.g. Netherlands and Spain) and it is clear that the European Commission would like to have something in common since the European experiences and elaborations are different one from the other.

The main focus of the Water Framework Directive is the good ecological status so in the first eight, nine years there has been a lot of attention on water quality and how to improve it while the water quantity was not really specifically addressed. And then it was an initiative of some of the member states to come up with a Floods Directive (2007). Parallel to that some tried to come up with a Drought Directive and that was not accepted by a number of other member states, particularly those of the north. Now it’s coming up again a new consideration of the Drought Directive. In the second part of next year Cyprus has the presidency of the European Union and they will put it high in their agenda.

Why didn’t the northern member states like the Drought Directive?
Since they believe that in some parts of the Mediterranean people use more water than is available, they consider the southern member states should make a clear difference between water scarcity and drought, first adapt their water management and then there could be a discussion on a Drought Directive.


How could groundwater be recharged in a climate where the temperatures will be warmer, there will be more evaporation from the soils and less water to supply them?
Something that was discussed during the Workshop on Climate Change Impacts on Groundwater (October 2011, Warsaw, Poland, organized by the WFD-CIS, EU Water Framework Directive Common Implementation Strategy Group, Working Group on Groundwater, with the objective of integrating the EU Groundwater Directive in the next generation of River Basin Management Plans) is that groundwater aquifers within a certain river basin could be used to store water during wet periods and use it during dry periods.

At a very detailed scale other measures, e.g. the reuse of irrigation water, can of course be applied. At a national or pan-European level it is much more complicated since so is to transport water. Nevertheless if you look at the river Danube, it has large aquifers in Germany and Hungary. If you used them to store water in wet periods you could also use them during dry periods but I have never heard of anyone seriously thinking of doing it.

Does building construction influence groundwater recharging and is it a relevant factor?
At a local scale it is but if you look at a larger scale the major impact is land-use change, e.g. afforestation and deforestation.

One of the questions you posed at the workshop was ‘Are we seeing an increase in the scale, frequency and severity of drought?’ Is it possible to state that such an increase is due to climate change?
If you look at annual river stream flows you see that northern Europe has had an increase over the last 45 years while southern Europe a decrease, which confirms what the climate models predict in terms of a drier southern and a wetter northern Europe. If you look at a monthly basis, though, what it comes out is that a large area of Europe, even parts of the southern one, is getting wetter, so the streamflow in winter is becoming a bit higher also in some parts of the Mediterranean while in summer there is lower river flow not only in the Mediterranean but also in Northern Europe.
So, can the reduction in river flows in summer be linked to climate change? In these terms I would hesitate a bit… It is clearly global change but more has change that only climate. We have more people, more intensive land-use, less forests and all adds to changes in river flows.


Finally you say that EU’s wish to seek an optimal balance between drought response capacity and drought prevention and preparedness will benefit from more focus on groundwater in large-scale models, drought forecasting (at least multi-month), besides better Science-Policy Interfacing. How are you addressing the first two within the project? There is still a lot of work that needs to be done on the improvement of the models, both the climate and the global hydrological ones. For the climate you need a model that includes the whole globe, the ice on the poles, the oceans, the land, but on the other hand these models are too coarse for impact studies at the river basin scale. The cells in the climate models have sizes of one to three, four hundred kilometres, a scale where you cannot study aquifers and groundwater. Since we know from the river basin scales that these are important we need to
improve the models, something that will take definitely more than three years.

The other issue is that the physical conditions in Europe make it very complicated to do a multi-monthly drought forecast. Compared to Australia and some parts of America, where drought forecasting is more successful, in Europe there is a weak link between the sea surface temperatures at the Atlantic Ocean, associated weather circulation patterns and drought on the continent. Understanding these teleconnections is essential for long-term drought forecasting. For a more short-term one the link with soil moisture is promising, something that will be further elaborated in the project.

If we improved computers capacity to run the models on finer scales and to include more processes, learn from historical droughts (such as the 1976 and the 2003 ones) if there are specific physical conditions that we can use if we see these developments in a particular summer season, we might be able to improve our forecasting, which would really help both local farmers and policy makers to be better prepared. We will try to make advancements but it will be a much slower process than people would like them to be and it will also take undoubtedly more than three years.
 

 

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