Area paesaggistica nel quartiere Neckarbogen a Heilbronn. Il nuovo lungofiume come motore di qualità urbana

In occasion of the biennial horticulture show in Heilbronn, a vast commercial and industrial zone west of the city centre was the object of an important requalification. In fact, BUGA 2019 represented an opportunity to redesign a once abandoned portion of the city, highly fragmented by the presence of infrastructural barriers. In 2005 the city acquired the areas of the historical port and prepared an intervention plan for a 40-hectare site. For the first time the Biennial hosted an architectural exhibition of 23 buildings for a planned further transformation on a 3-hectare site in parallel with the layout of the gardens. Plans called for the construction of the Neckarbogen at the end of the 173-day exhibition: a new residential quarter for roughly 3,500 inhabitants and the object of a design competition in 2008. In 2010 a general masterplan was adopted and a new competition organised for the design of the open spaces, awarded to the Berlin office Sinai in 2011. Beyond the pure programme of the exhibition, a more general objective at the urban scale focused on the inheritance of an urban spatiality with a highly recreational value, capable of permanently enriching the city. Mobility infrastructures and physical-visual barriers were removed to guarantee that the riverfront could function as a connective element at the scale of the city. With the aim of valorising water as a resource that drives widespread urban quality, two artificial lakes were created in the area of the former port: the Karlssee, the larger of the two, and the Floßhafen, at the heart of the residential complex under development. To maintain the level of water in the lakes, an innovative system was studied to treat and reuse rainwater. While the first was filled using water from the Neckar River, a dedicated mechanism implemented to collect surface runoff from the new quarter regulates the level and quality of water. The site was subdivided into five so-called “atmospheres” or landscape strips, each with a specific focus on the themes of the exhibition and a particular functional characterisation of open spaces. In direct relation with the river, the Neckaruferpark hosts seating and rest areas along terraced banks of the Neckar, which also function as buffer zones against flooding. Hafenpark, the “park of the port” on the Karlssee, is connected to the Neckar by “steps on the water”. Animated at night by spectacles and fountains, the park offers a suggestive lakeside landscape and a wood walkway suspended above the water. On the other side of the river, the Campuspark and Kraneninsel offer citizens new programmes and activities, directly related with the area’s principal urban functions: the campus of the University of Applied Sciences in Heilbronn and the “Experimenta” science museum. The Campuspark is the principal centre for sport, while the Kraneninsel is home to the so-called “Urban Jungle”. The master plan reinterpreted the existing fabric, reinforcing the continuum of riverside spaces in relation to the principal landscape strips identified along the riverbanks. At the same time, various functions essential to the quality of dwelling and the environment in the area were implemented and integrated in the general project

In occasione della mostra Biennale di orticoltura tenutasi a Heilbronn1, una vasta zona commerciale e industriale a ovest del centro città, tra il canale del Neckar e Altneckar, è stata considerevolmente riqualificata. Il BUGA 2019 ha infatti offerto l’opportunità di ridisegnare questa porzione urbana precedentemente abbandonata e fortemente frammentata dalla presenza di barriere infrastrutturali come strade e linee ferroviarie. Nel 2005 la città ha acquisito le aree degli storici bacini portuali e predisposto un piano di intervento su una superficie di circa 40 ettari. Per la prima volta nell’ambito della Biennale, parallelamente all’allestimento dei giardini è stata proposta una city exhibition, una mostra di architettura su tre ettari dell’area con 23 edifici realizzati in previsione di un’ulteriore trasformazione del sito. Successivamente ai 173 giorni dell’esposizione, è stata infatti prevista l’edificazione di Neckarbogen, un nuovo quartiere residenziale di circa 3.500 abitanti2 per il quale nel 2008 si è svolto un concorso di progettazione. Nel 2010 è stato poi adottato un masterplan generale e indetto un nuovo concorso per il progetto degli spazi aperti, di cui lo studio Sinai di Berlino è risultato vincitore nel 2011. Al di là del programma strettamente allestitivo, un più generale obiettivo alla scala urbana ha puntato all’eredità di una spazialità dal forte valore ricreativo, in grado di arricchire la città in modo permanente offrendo l’opportunità di passeggiare, fare jogging, andare in bicicletta, rilassarsi sulle rive del fiume a pochi minuti a piedi dal centro della città. Le infrastrutture per la mobilità e gli elementi di barriera fisico-visiva sono stati rimossi per garantire al lungofiume la funzione di elemento connettivo alla scala della città.