Campina de Faro aquifer

Description

The Campina de Faro aquifer system, located in Algarve, has an area of around 86.4 km².

According to the last river basin management plan, the Campina de Faro aquifer system is classified as poor groundwater quality status in the East and poor quantity status in the West. The Easternmost system of the aquifer is an area of significant agricultural pressures which lead to high input of nitrates in the aquifer during the last 50 years. On the other hand, the Westernmost system of the aquifer is a highly touristic area, famous for its golf courses, and has shown decreasing trends on groundwater levels over the last 20 years, and consequently, seawater intrusion.

The role of groundwater discharge as a vector for nutrient transport to the protected coastal lagoon Ria Formosa has been well established. Initial estimates of the contribution of groundwater nitrogen (N), based on regional water balance and N loads for the entire catchment of the lagoon is in the order of 700 ton/year.

The Campina de Faro aquifer is limited to the North by the less permeable deposits of Cretaceous, to the East by Quelfes aquifer system and to the West by the Quarteira aquifer. Main flow direction is from North to South and main discharge from aquifer occurs at protected habitat coastal lagoon Ria Formosa.

Rainfall in the area is 550 mm and recharge rates vary between 15 – 20%, which results in a natural recharge of 10hm3/year.

The following pollutions sources are identified: International Faro Airport, several wastewater treatment plants, one landfill (point sources); several roads and highways, train lines, and a commercial port (mobile sources); agriculture, and septic tanks (diffuse); saltwater intrusion.

Location and extension

Campina de Faro aquifer system is  limited to the North by the less permeable deposits of Cretaceous, to the East by S. João da Venda – Quelfes aquifer system, to the West by the Quarteira aquifer. These aquifers are thought to be connected. 

Main flow direction is from North to South and main discharge from aquifer occurs at protected habitat coastal lagoon Ria Formosa (Natural Park).

Challengues

• Involving stakeholders in a co-production of solutions which is a new paradigm of research in this context. Cooperation among users, public authorities and researchers is limited. Yet, the solutions will necessarily involve varied sectors and public institutions.
• Co-create proximate nature-based solutions including the aquifer, together with stakeholders and using recent hydrogeological research. This is a challenge because it is against the dominant paradigm based on surface water and infrastructure building.
• Enhance information sharing on abstractions, and users’ practices.
• Uncertainty about some hydrogeological features related to the interconnection between contacting groundwater bodies, location of the saline front, localized water extractions,  and distributed water use by tourism, agriculture and disperse

Oportunities

• Increased perception of urgency among touristic agents and agriculture. A new drought episode is decreasing water levels, and is bringing forward the need to implement a structural solution to water scarcity.
• Increased costs of water abstractions are boosting user’s interest in the optimization of water use. Users are already interested in knowing more about the dynamics of the aquifer.
• The critical situation of water in Algarve, may trigger openness to innovative solutions by water managers 

Improvement in the understanding of the following points:

• Human pressures acting upon the aquifer system,
• Hydraulic behaviour
• Quantitative and qualitative state
• Relationships with connecting water bodies

The improved understanding opens an opportunity to explore the development of a new groundwater management model.

The project will also contribute to:

• Capacity building in the area.
• Improve data.
• Detect bottlenecks by building a framework for sustainable groundwater management
• Develop quantitative indicators for cyclic cause-effect relationships between driving forces.

These quantitative indicators will be constructed based on ICTs which will provide enhanced information systems combined with citizen science. Mathematical models can then be used to help quantify these indicators, which, which will be fed back to stakeholders. The impacts of different management alternatives will be discussed in participatory context. The involvement of stakeholders will greatly increase the likelihood its adoption

Legal framework

• In terms of water management, Campina de Faro is currently separated in two systems by the river administration basin. At the Eastern system, Sub-System Faro, with a recharge of 6.2 hm3/year, agriculture is the main water use, responsible for about 88% of total water abstraction (3.22 hm3/year).
• At the Western system, Sub-System Vale do Lobo, with a recharge of 4.6 hm3/year, the main sectors responsible for water abstraction are the Golf sector, responsible for 41 % (2.7 hm3/year) of total water abstraction and “others”, in which touristic sector is included, which account for 48% (2.55 hm3/year) of total water abstraction.
• Several wells are kept as reserve for tap water supply in the event of water shortage (at present the regional tap water supply utility uses an optimized share of surface and groundwater sources, but none from this aquifer).
• The Portuguese Environment Agency is responsible for the water resources management, including licensing of abstractions and land use.

Activities

1. Demonstrate the benefits of EIS for groundwater assessment and modelling, and more specifically to assess the impact of EIS on the reduction of uncertainty when estimating parameters and budgets.
2. Study the impact of conceptual groundwater flow model uncertainty. The objective is to confront the scientific vision with local lay knowledge in order to improve the conceptual models of the aquifers. Lumped and distributed groundwater models will be developed or updated and used to simulate the hydrogeological response of the aquifer under different conditions.
3. Study the impact of new data on conceptual uncertainty.The objective is the assessment of the impact of data collection methods on models’ conceptual uncertainty, and to provide guidelines to reduce uncertainty by collecting more cost-effective data.
4.  Study the impact of new data on parameter uncertainty. Methods such as the generalized likelihood uncertainty estimation will be used for dealing with parameter uncertainty.

5. Plan of adaptation to Covid restrictions: webinars and online discussion on pertinent themes related to the aquifer and its governance.

6. Improvement of groundwater monitoring with the installation of data loggers in chosen wells. In complement manual monitoring by stakeholders is planned for the near future.

7. Development/improvement of detailed numerical groundwater flow models for both the entire water body, as well as for particular areas where seawater intrusion into the aquifer is suspected.