Barcelona Field Studies Centre

River Llobregat Water Reclamation Project

A Visitors Centre has been opened in May 2007 that provides access to the new delta wetlands created by the River Llobregat water reclamation project.

Advertising the new Llobregat Delta Visitors' Centre
Advertising the new Llobregat Delta Visitors' Centre

The delta of the river Llobregat lies to the south of Barcelona and covers about 100 square kilometres. In spite of its very close proximity to the city, it constitutes one of the most valuable natural areas of the region. The wetlands are of international importance for wildlife and form a valuable wintering ground for many migratory species of birds. The delta aquifer is one of the most important fresh water resources of the Barcelona area,  forming an underground source with a capacity of 100 million cubic metres of water. Numerous industries, agriculture and the population of the delta town of Prat de Llobregat use its water, extracting it through wells. The fertile delta farmland supports intensive agriculture to supply the local markets and as protected Green Belt land, helps restrict urban sprawl.

Since the 1960s, the delta and associated traditional land uses such as market gardening have been under constant attack from Barcelona's urban and industrial expansion. Catalonia’s most important logistics and transportation infrastructures have become concentrated in the area: port, airport, motorway network and railways. Less than 5% of the original wetlands remain and in some municipalities half of the agricultural land has been lost in the last decade.

By the end of the 1980s, the Llobregat was one of the most polluted and degraded rivers in Western Europe. Over-exploitation of the underground water had led to salinisation of the aquifer, with 30% now being unusable. The most recent city projects that affect the area are summarised in the Plan for the Llobregat Delta below. Future threats include the impact of rising sea levels.

Plan for the Llobregat Delta
The Plan for the Llobregat Delta consists of a set of coordinated projects and investments in transportation, logistics and environmental infrastructures to be carried out until approximately 2010. This will enable Barcelona to become one of the gateways of Europe as well as a bridge to Latin America and the Mediterranean.
Total surface area
1,000 ha
Main projects
The Plan includes the following projects:
1. Diversion of the Llobregat river and environmental improvements.
2. Expansion of the Port and creation of a Logistics Activities Zone.
3. Expansion of the Airport.
4. Road and railway infrastructures

Since 1991 and after the European directive on urban wastewater, a comprehensive programme of water treatment plants has been implemented along the river and the situation has improved dramatically. For example, the beach at Prat de Llobregat, near the mouth of the river, was a principal pollution black spot along the Catalan coast. It has been open now for bathing since 2002.

The objective of the new water reclamation project is to maintain the ecological flow of the Llobregat river which runs through Barcelona by partly closing its access to the sea. The reclaimed water that was previously lost to the sea is pumped upstream to increase the natural flow of the river as well as to provide capacity for agricultural and golf irrigation and the recharge of wetlands. The reclaimed water receives additional reverse osmosis treatment for aquifer recharge to control seawater incursion and salinisation.

This is an innovative water scarcity solution that is applicable to all large coastal cities. The project not only preserves the habitat along the length of the river and the marshlands at its delta, but also supports the tourism business by helping Barcelona to maintain its reputation as one of the most beautiful cities in Europe. In addition, the scheme has low carbon impact as the process works by gravity. It is one of the largest wastewater reclamation projects in the world and the first major tertiary water treatment facility (eliminating nitrogen and phosphorus nutrients) that saves approximately 80% of the energy used in conventional plants.

The water purifier has a capacity of 50 million cubic metres of water per year and cost 260 million euros, with an 85% contribution from the EU Cohesion fund. “It is the largest investment in cleaning and purification of water in Spain”, said the Environment minister, Elvira Rodriguez, during the opening of the plant.


River Llobregat water reclamation scheme
River Llobregat water reclamation scheme


New wetland created at the mouth of the River Llobregat
New wetlands created at the river mouth


A submerged breakwater at the river's mouth has helped create a wide artificial channel
A submerged breakwater at the river's mouth has helped create a wide artificial channel


Llobregat river diversion
Diversion of the river to create the new channel

River Llobregat immediately upstream of the managed channel
River Llobregat immediately upstream of the managed channel

Glossary

Green Belt

A green belt is undeveloped or agricultural land surrounding an urban area where development is heavily restricted by law. The purpose is to protect natural environments and wildlife, improve air quality, ensure that urban dwellers have access to countryside and protect the character of rural communities which might otherwise be absorbed by expanding suburbs.
Barcelona's Green Belt

Logistics

Logistics is the management and control of the flow of goods and services from the source of production to the market. It involves knowledge, communication, transport and warehousing.

Reverse Osmosis

Reverse Osmosis involves forcing water through a porous semi-permeable membrane. The small pores of the membrane block salt and other natural minerals, which generally have larger molecules than water. These pores also block bacteria. Thus, reverse osmosis is very effective at desalinating water and providing mineral-free, clean water.

Salinisation of the Aquifer

An aquifer is an underground layer of permeable rock from which water can be extracted using a well. Water in an aquifer is called ground water. The Llobregat delta aquifer has a layer of fresh water near the surface and denser salt water under the fresh water. Salt water penetrates the aquifer by moving in from the sea. The thickness of fresh water on top of the salt water is normally about 40 metres of fresh water for every metre of salt water above sea level. Too much ground water in the delta has been pumped from wells for agriculture, domestic use and industry, leading to salt water intruding into the upper layers of the aquifer causing contamination of freshwater supplies.

Urban Sprawl

The unplanned and uncontrolled growth of urban areas into the surrounding countryside.
Barcelona's Urban Sprawl

 

Impact of rising sea levels on the Llobregat Delta