Onyar River

In Mediterranean regions like ours, riparian forests—or gallery forests—are highly productive ecosystems. They grow on both sides of river courses, so they rarely lack water and their soils are very rich in nutrients. They are therefore home to a great diversity of flora and fauna.

Its vegetation plays a very important role for the ecosystem, as it serves as a refuge for flora and fauna, functions as a biological corridor (very important in areas highly fragmented by human infrastructure), acts as a filter for river water, functions as a flood buffer, improves the recharge of aquifers, etc.

The Onyar River, which rises between the municipalities of Brunyola and Vilobí d’Onyar , makes its way through the Selva plain towards Girona, where it joins the Ter River. The flat morphology of the Selva depression, through which the Onyar flows, has led to a great development of human activities, which is why it is vital to preserve all the riverside forests that are associated with it. Among these forests, the vernedes, dominated by alders (Alnus glutinosa), displaced by timber plantations of poplars, bananas, etc., stand out.

In the Onyar groves you can see, in full bloom, at the end of winter or the beginning of spring, when the sun still penetrates the forest before the alders shed their leaves, herbaceous species such as boxwood (Anemone nemorosa), snowdrop (Galanthus nivalis), liverwort (Anemone hepatica), buttercups (Ranunculus spp.), martagon lily (Lilium martagon) and a long list of others. And, associated with all this vegetation, there is a long list of fauna, ranging from mammals such as the badger (Meles meles) and amphibians such as the salamander (Salamandra salamandra) to a long list of birds, such as the moorhen (Gallinula chloropus), among many others, which find oases in the riverside forests in the middle of highly transformed areas.

You can discover the values ​​of the riverside forests on the various hiking or cycling routes in the municipality. Always do so respecting the environment and behaving in a civic manner, so as not to disturb these fragile and, at the same time, necessary ecosystems.

The floods of the Onyar River

Riudellots , located on the plain of La Selva, about 100 meters above sea level, is a town of rivers and streams located in an area where all the waters coming from the Gavarres, the Cadiretes massif and part of the Guilleries come together. The rivers, which can sometimes be seen completely dry, suddenly swell at certain times of the year, greatly increasing their flow and flooding the surrounding lands. Therefore, it is an area prone to flooding, swampy, full of fens and river arms with stagnant water. This situation has been preserved in the toponym of the town: riu de llots!

Riudellots had to change location in 1340 due to frequent floods, documented since 1322, as the town was located in the middle of two streams: the Cric and the Riudevilla. The promoter of this change was the cleric Joan Nadal, lord owner of the new land on which the current town was built, who had hidden economic interests.

But, despite the relocation , the floods continued. The Onyar has overflowed on several occasions. The most famous flood was in 1884: the water reached 2.5 meters at the lowest point of the town. Although efforts have been made to combat floods, the phenomenon of flooding is not something that has been happening in the distant past. Proof of this is the flood that flooded the town in 1962.

In 1977, drainage works were carried out on the river and a new bridge was built, as the existing one often blocked the waters of the Onyar and caused floods.