The shape of water.

Water is one of the most changing elements on the planet. It flows noisily in rivers and rests in lakes, falls silently when temperatures drop, changing the color of the landscape by enchantment, impregnates the air with its ephemeral presence just before the rain falls. A considerable volume of rainwater disappears from our eyes by infiltrating underground. If it is evident that the soils, sands and gravels that make up the valley bottoms or the undergrowth receive large quantities of water, we often forget that the mountain ranges also constitute vast reservoirs of water. The water is not absorbed by the rocks but percolates, flows, accumulates in fractures, ducts and cavities. Emilia-Romagna is also a land of mountains: in addition to the liquid state, it is therefore easy for us to think of water in a solid state, for example when it falls in the form of snow and feeds glaciers. Here, what happens to glaciers over time? Photographs, illustrations and stories testify that, until the beginning of the last century, glaciers descended to relatively low altitudes in the Apennine valleys. When they retreated upwards, colonization by plants and animals was particularly rapid and, in less than a century, where there was previously ice, rocky debris and species adapted to the cold, woods have appeared. When this happens quickly, as in the last two centuries, these ecological dynamics generate a sort of run-up, a sky-race of organisms that rise higher and higher, following the glacial microclimate and the vegetation that rises upstream. This process grants more space to low and medium altitude ecosystems and the conquest of new territories favors the evolution of new species, but at the same time condemns all cryophilic species to extinction, that is, those adapted to life near the glacier. It is the so-called summit trap, or summit-trap: when you have reached the top of a mountain, you have no other place that is colder or with more ice to take refuge. These are evolutionary stories that end at the foot of the summit crosses. Liquid water, solid water: there is another state in which water occurs and, moreover, has an equally fundamental role for life on Earth. In fact, even trees are an important piece of the hydrological cycle: a forest returns thousands of cubic meters of water into the atmosphere in the form of humidity and minute droplets. Evotranspiration, the quantity of water that evaporates from the surface of the soil and transpires through the foliar apparatus of plants, is a pivotal process in the terrestrial hydrological circulation, as well as in the regulation of winds and temperatures and therefore also in the distribution of organisms that these factors depend. Even on a local scale, the water that becomes vapor, due to the joint effect of the transpiration of plants and evaporation from the ground, is an important factor in characterizing climate and biodiversity. We could also venture another state, or dimension, of water: the time dimension. The water that imperceptibly modifies the landscape day after day; the water that explains the forms of the territory and justifies the presence of organisms that no longer exist today. The ancient Romans said "gutta cavat lapidem" (the drop pierces the stone), we could call it the "memory of water". The Apennine valleys show this clearly: it is the action of the rivers that dug deep ravines millions of years ago, it is the strength of the ice that shaped the slopes thousands of years ago, it was the lakes that characterized landscape shapes and typologies of vegetation of some valley bottoms occupied until a few decades ago. Finally we can also venture a fifth dimension of water, linked to the sounds it produces: the sound of water is even more the sound of the people who, thanks to the water, have given shape to territories and traditions and who, reciprocally , from the water have been culturally defined. Location: Lake Santo di Modena and Lake Baccio, Modena Apennines Soundtrack: Pink Floyd Ummagumma and Atom Earth Mother Drone: mini 2