In the New Crossing project, great importance was always given to environmental issues. A commitment was made to ensure that the project would have as little impact on the environment as possible. Given that the Vasco da Gama Bridge is located at an environmentally sensitive site - the Tagus estuary - it was immediately agreed upon that the project would be located approximately 4km south of the Nature Reserve of the Tagus Estuary (RNET) in order not to directly affect this area.
It should be noted on the other hand that the Special Protection Zone (ZPE) of the Tagus Estuary was increased (D.L 280/94, November 5) by 12,000 hectares as a way to environmentally compensate the construction of the new crossing.
The preliminary Environment Impact Studies and the work carried out by the technical teams for the Environment Area were considered from the onset of the project thus attempting to guarantee that appropriate measures would be taken to minimize the impacts that a development of this scale would inevitably have on the area.
This area of the environment was very rigorously developed and monitored in terms of costs. Costs resulting from the implementation of the mitigating measures and the adoption of an environmental assessment methodology which was not confined to the licensing phase of the project and continued into both the construction and operation phases. For this purpose a Project Monitoring Committee (CAO) comprising representatives from the Ministry of the Environment, the Municipalities involved in the project, representatives o of local and national NGO's and the Environmental Monitoring Research Centre (CEMA) under the responsibility of LUSOPONTE was created.
This circumstance is especially relevant because in addition to helping monitor the evolution of environmental impacts, it also helped check whether the compensatory and mitigating measures foreseen were being properly implemented.
During the first quarter of 1994 an Environmental Impact Study was conducted for the new Road Crossing over the Tagus. This study was submitted to public opinion and was approved by the government and by the European Commission in October of the same year.
One of the objectives of this study was to recommend measures to minimize and monitor the reduction of environmental impacts of the Vasco da Gama Bridge during construction and its operation.
Lusoponte, Concessionária para a Travessia do Tejo, S.A., engaged in the commitment to implement these recommendations expressed in the EIS and for this purpose set up the Environmental Study Monitoring Centre - CEMA, its main objectives being to:
- Implement the monitoring programmes.
- Establish a chronological record of environmental indicators, parameters and values.
- Monitor and assess impacts effectively caused by the new Crossing during the construction and operation phases
- Contribute to the assessment of the efficiency of the established mitigating measures.
- Record and supply information applicable to the drafting of EIS for future similar projects.
The diversity of the zones occupied by the New Crossing implied the adoption of mitigating measures appropriate to the specificity of the impacts.
CEMA relies on the support of independent consultants experienced in the environmental monitoring of the different descriptors. In the current phase of operation of the Vasco da Gama bridge the water quality, bio-indicators and macrozoobentonic descriptors are monitored by IPAMAR - Fisheries and Sea Research Institute, the bird fauna and flora vegetation descriptors are monitored by Naturibérica, the air quality descriptor is monitored by ISQ - the Welding and Quality and finally the sound component is monitored by Sound and Environment Engineering.
During the construction phase of the bridge other descriptors were monitored but were meanwhile abandoned as they were no longer related to the impacts associated with the operation of this New Crossing. These descriptors were hydrodynamics, the quality of sediment on the river bed, icthyofauna, herpethofauna and archaeology.
During this phase interesting studies were also conducted on local socio-economic aspects.
Some of the permanent measures to mitigate impacts implemented by the concessionaire Lusoponte included the renovation of the Nossa Senhora da Conceição dos Matos Chapel in Samouco, the installation of close to 5000m2 of sound barriers and in Samouco the construction of three decantation tanks and the collection of oil coming from the rainwater run-off from the bridge.