Environmental recovery of the river Llobregat in the comarca of Baix LllobregatEdit profile
PREVIOUS SITUATION • Urban metropolises are the product of superposing uses and infrastructures over the original territory, building up a non-compact urban continuum that includes many empty spaces that tend to correspond to natural features such as mountains or rivers. • Despite the conventional city’s constant attempts to erase the physical elements that predate its development, some of them refuse to disappear and account for many of the empty spaces on which the city turns its back. But the city is underlain by geography with its physical phenomena that do not disappear, which we can transform into public spaces for the metropolis, environmental reserves that promote biodiversity in urban settings. • The river Llobregat runs through the metropolis of Barcelona, but it has historically been maltreated. At one point, it was like an open sewer, its flow was reduced to a minimum and all the infrastructures the metropolis needed were laid out beside it, making access to its embankments impossible. For a resident of Sant Boi del Llobregat, it was practically impossible to get to the river, as it was separated from the town by an expressway, a railway line and an irrigation canal. AIM OF THE INTERVENTION Two complementary viewpoints were used to address the environmental recovery of the river Llobregat: The river as a natural space The river is a living, changing entity that is full of life, with its own dynamics of functioning. The river as a public space The river can be a leisure space, with routes along the riverbanks and easy access from the city and surrounding towns and villages. The completed stretch extends 6 km between El Prat de Llobregat and Sant Boi de Llobregat. DESCRIPTION The river as a natural space. Stream deflectors Interventions on the embankments concentrate on addressing specific points that will allow the river to react in terms of hydraulics and associated plant life. This is a proposal for the mid- and long term, and results will not be very visible at first. A process of naturalization of the river is implemented to allow it to gradually advance without the hand of man being apparent. The introduction of small elements to alter the course of the river (stream deflectors) serves to reconfigure its meanders at low water levels. At certain points, all the introduced species were removed and replaced with selected species to create patches of native flora that should gradually expand and colonize the embankments. The river as public space. Embankment paths Both banks have levees to provide protection at high-water level and to separate the river from nearby farmland and urban spaces. Running along the top of the levee was a service road with no logical approaches that was sometimes cut off by the various infrastructures across the river. The proposal aims to restore continuity to these paths, thereby creating a layout of routes along both embankments allowing resident access to the whole of the new system. This involves removing the various obstacles and providing the necessary access. Different points are created to cross the levee from both the river and the town sides, the surface of the track is improved and waterside vegetation is planted. Once the interventions to the tracks are complete, a network of riverside paths will join all the adjoining municipalities from El Prat (near the sea) to Martorell, on both banks, representing uninterrupted routes of over 30 km. The river as public space. The car park at El Prat de Llobregat The landscape proposal envisions the river as a green space connected to the town and its surroundings. It addresses the relation of the various towns with the river, transforming what is currently a boundary into a more urban connective element, interrelating the two sides of the river, drawing together the existing networks of paths and proposing suitable vegetation for the available water resources. The car park at El Prat provides access to the river from the road network. From this point, visitors will be able to get onto the embankment and follow the paths along the river. The project brings the same formal treatment to all the necessary elements, introducing a single geometric system that unifies such varied elements as a stream deflector, a sector for plants to colonize, a crossroads, a car park or a bridge. The river as public space. The town limits of Sant Boi de Llobregat The project aims to make the river easily accessible from the centre of the town of Sant Boi de Llobregat. A small bridge over the expressway becomes a vantage point overlooking the river and a gateway to a previously unimaginable open space. This bridge links up with the system of riverside paths that leads downstream to the sea, along a barrier-free path of over 10 km, or upstream to Martorell, with over 20 km of paths. This place is the former site of illegal vegetable allotments that had to be eliminated as they came within the river’s flood plain. At the same time, the embankment walk was cut off by the existence of two culverts that drain into the Llobregat. The project ensures the continuity of the riverbank with the construction of two bridges over the existing culverts. The operation is completed by a hardwood plantation that occupies the available area. The bridges are built of concrete to withstand flooding, with the same formal treatment as other new elements, and become landmarks on the new paths, their mottled markings reminding us that we are walking through a system made up of drops of water. ASSESSMENT • The Llobregat becomes a new public space for the metropolis. • It is a public intervention at the service of residents. • The intervention facilitates resident access to this new public space. • The project overcomes existing physical barriers. • Work begins on the environmental recovery of the river. • High potential of use by residents who leave the city to enjoy the river. • An interdisciplinary approach: environment, ecology, engineering, urbanism, architecture and landscape.