Water as Leverage, Cartagena

The Marbella–Crespo coast, from the walls of the historic centre to La Bocana. The task is coastal pressure: flooding from the sea, erosion of the beach and a seafront with no good place to walk or cycle. The project makes the coast a park-promenade. The beach road becomes a boulevard with new development behind it, and the promenade runs on into the city. The first step is an elevated cycle route and drainage collectors, within eighteen months. Then the waterfront park and a sand motor that feeds the beach from the sea.

La Boquilla, the fishing community on the narrow strip between the Caribbean and the Ciénaga de la Virgen. The task is to keep the bond between the community and the mangrove intact while both come under pressure: floods from lagoon and sea, eroding banks, roads that go under. The project restores the hydrological connection between sea and lagoon at La Bocana and Punta Canalete, protects and replants the mangrove, renaturalises the beach, adds sustainable drainage and opens training centres run by the community. Later come seagrass and coastal ecosystems, urban tidal canals and raised access roads.

The canal zone of San Martín, Líbano and Salim Bechara, whose canals drain into the Ciénaga. The task is the canals themselves and the water they carry: stormwater and pollution running to the lagoon, and the lagoon flooding back into the streets. The project keeps the canals working as water, social and ecological space at once. Canals are cleaned and renaturalised, streets rebuilt as climate streets with drainage, and water plazas, water playgrounds and water towers become the neighbourhood's meeting points. In the long term a freshwater reservoir inside the Ciénaga regulates sea-level rise while keeping the lagoon's balance.

The arroyos Calicanto Nuevo, San José, La Princesa, Isla de León and El Limón, the Calicanto canal and its tributaries. The task is runoff: rain that falls on the high, partly rural parts of the basin and discharges into dense, low-lying neighbourhoods with no room for it. The project holds the water up high. Temporary storage and infiltration in the elevated areas, helped by limestone soils that drain well, sponge principles in El Triángulo, and the streams that feed the Ciénaga kept open and maintained. Canals cleaned, climate streets, reforestation, bioretention and floodable wetlands first, with training centres alongside. Later sponge neighbourhoods and parks, NbS on buildings, urban farming and a local treatment plant.

The Caños and Lakes: two sub-basins in San Pedro, Petares and Daniel Lemaitre, on the steep slopes of Cerro de la Popa, running down to the Juan Angola channel. The task is water that races off the hill and erodes the channel banks below. The project starts high: reforestation and bioretention on the slopes, streets redesigned to slow the water on its way down, protected banks and mangrove along the channel. Along the canals a floodable Eco-Park is the pilot and the long-term axis: a tidal ecosystem where public functions and new development adapt to a floating environment. Later come the tidal park, flood gates and drainage pumps.

The basins of the Puerta de Hierro, Arroz Barato and Policarpa streams, running through the port and industrial zone into the Bahía de Cartagena. The task is connection: catching runoff upstream, bringing the streams through the harbour as one drainage network and protecting what stands downstream. The project restores and connects the natural drainage network, reforests wasteland, protects ecologically valuable banks and islands and gives port and industry local protection. Floodable areas in the neighbourhoods serve recreation. The remaining ecological space beside the port becomes a natural filter: mangrove that cleans the outflow, holds sediment, breeds commercial fish species and rises with the sea.