The rain in Spain …

“… falls mainly on the plain! The rain in Spain falls mainly on the plain!”. I’ve never understood this lyric, commonly attributed to a key scene in the My Fair Lady musical. Actually, this turns out to be an incorrect version (“The rain in Spain stays mainly in the plain!” – see but even this lyric doesn’t make any sense in hydrometeorological terms. Atmospheric moisture in Spain falls mainly in the mountains, and especially along its Pyrenean border with France and Andorra. Here, there are summer and autumn thunderstorms, some of ferocious intensity (more than 100 mm of rainfall in 24 hours is not uncommon), but much moisture also falls as snow, releasing liquid water only during the spring melt. Rivers then carry some of this water south to the plains, but this supply doesn’t stay long in the typically hot, desiccating conditions.

Perhaps the different versions of the lyrics reflect wishful thinking in Spain. Outside the Pyrenees, many Spaniards – especially those in the fast-developing population centres farther south – wish that the rain would either fall on or stay in the plain. The lower lying lands are where the water is needed most; for agricultural, industrial, and domestic use, and over recent decades, for a spectacular number of tourist developments. Having long recognised this imbalance in water supply and demand, Spain has developed numerous major dam building and inter-basin water transfer schemes, many initiated under the mid-20th century Franco dictatorship. Spain is said to now have more dams than any other similar-sized country. But even in the post-Franco era, and despite some cities having made big strides in reducing their water footprints (, new water schemes continue to be proposed. Population growth and agricultural demands are one set of pressures. Creeping afforestation of abandoned farmland in the Pyrenees is another concern, for trees consume much water, reducing the supply to rivers and reservoirs. And climate change projections that almost universally paint a picture of an overall hotter, drier future Spain further add to the urgency.

As in many countries worldwide, many of these dam building and water transfer schemes are highly controversial. Social dislocation, spiralling economic costs, political and legislative wrangling, and severe environmental impacts (e.g. devastation of river ecosystems, declining water quality) create a toxic cocktail of issues that are not easy to untangle, let alone resolve. Should local and regional objections override national policies for addressing imbalances in water supply and demand? And regardless of the answer, should water be the overriding environmental management issue in Spain? What about soil erosion control and management of terrestrial carbon stocks?

Impacts on water supply aside, could the creeping afforestation of the Pyrenean slopes actually be a good thing? Forest canopies, leaf litter, and root networks reduce the impact of rainfall and surface runoff on the fragile land surface, helping to slow the nutrient-stripping soil erosion that ultimately reduces reservoir capacity. Forests do this while drawing down carbon dioxide from the atmosphere and storing it in their leaves and woody tissue, helping to mop up some of the emissions produced by other activities. And might not afforestation also benefit some forms of wildlife (perhaps deer and brown bears)? But – and when considering environmental processes there always seems to be a ‘but’ – increasing forest cover increases the risk of devastating wildfires, which are expected to increase in frequency and severity under a hotter, drier future climate.

So where do the priorities for environmental management in Spain lie? With water, soil, carbon or wildlife? Given obvious incompatibilities, can the necessary trade-offs be identified and negotiated? Spain is not unique in facing these kinds of questions but as one of the countries thought to be most sensitive to environmental change, how it tackles them may offer useful lessons that can be applied elsewhere.

As part of this ‘learning lessons’ theme, an Aberystwyth University colleague and I have just returned from a week-long student fieldtrip to northeast Spain where we examined these and other related topics. This fieldtrip forms the centrepiece of a new MSc in Environmental Change, Impact and Adaptation (see Judging by the smiling faces and positive vibes evident in twitter feeds, examples of which are provided below, the inaugural cohort of ten students all seemed to have enjoyed and benefitted from the experience.

jazz hands tweet cropped

Initially, we based ourselves in Jaca, located in the subhumid Pyrenean foothills, where the main discussion themes revolved around reconstructing long-term environmental changes (glacial dynamics, river activity, wildfire frequency), evaluating recent human impacts (land abandonment, dam building), assessing hazards (flash floods, debris flows), and the balancing of those competing environmental management priorities (water, soil, carbon, wildlife).

infiltration tweet cropped

Practical work involved estimating soil infiltration and runoff on different land cover types around the controversial Yesa reservoir (bare rock, ploughed land, natural shrubland, and forest plantation). The results of field experiments proved stubbornly difficult to describe and interpret, but this itself provided a valuable lesson in trying to match field reality with textbook theory.

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We then based ourselves in Alcañiz, located in the centre of the arid Ebro Basin, where we examined similar themes but with greater emphasis on dryland processes, reflecting the fact that here drought and wind erosion can be important drivers of environmental change.




soil CO2 tweet croppedPractical work involved quantifying soil carbon dioxide gains and losses from around the edge of one of the numerous saline depressions in the region. In this instance, the results seem to match more closely with textbook theory, and the main lesson is the need to consider the impact of future climate change on our below-ground carbon stores.




CSIC tweet cropped


At the tail end of the fieldtrip, we visited the Instituto Pirenaico de Ecología (IPE –, located on a small campus just north of Zaragoza, where we were shown around the facilities and treated to talks by some of the excellent staff present. Despite ever-present funding uncertainties, over the last decade, IPE personnel have produced numerous high-quality publications that have both advanced the earth and environmental sciences and also informed management of Spain’s changing environment. Using IPE’s lead, countries farther afield can certainly learn lessons about how to translate excellent science into sound policy.

So, overall, this was a highly successful fieldtrip. Even a gentle brush with the Catalonian police on the way back to Barcelona Airport seemed to add to the experience. Here, the lesson to be learned is to not ignore a fence – albeit a poorly maintained one – around a roadside Spanish Civil War site. All we really wanted was a better view of the surrounding hills with their impressive array of wind turbines, other symbols of Spain’s proactive management of environmental change. No harm done … all those hours that I spent in Spanish lessons paid off. A bowed head and three simple words defused the situation: “Lo siento mucho” (“I’m very sorry”). I think that even the police seemed to find my grovelling amusing.