Green filters and wetlands of the Mar Menor: what the EIA approves and who it affects in 2026

Key data

Two natural purification facilities receive environmental approval on September 17, 2026. The Resolution from the General Directorate of Quality and Environmental Assessment (reference BOE-A-2026-19403) issues a favorable EIA for the basic projects of green filters and semi-natural wetlands in El Albujón and Los Alcázares, two of the actions included in the Framework of Priority Actions for the Mar Menor. This is not a final construction authorization: the EIA is the prior environmental step, but the promoter must still obtain the remaining sectoral authorizations before executing the works.

What does this regulation establish?

The EIA environmentally approves two differentiated actions within the Framework of Priority Actions for the Mar Menor. Each has its own characteristics:

The system works by extracting water from the quaternary aquifer of the Campo de Cartagena through continuous pumping at 35 liters per second. That water first passes through organic wood chip filters and then through subsurface flow wetlands planted with reed, achieving 97.5% efficiency in nitrate removal.

In addition to water treatment, the resolution includes two additional environmental commitments:

• Revegetation with native species in the action areas.
• Recovery of the priority habitat 1510* salt steppes, classified as a priority habitat of community interest according to the Habitats Directive.

The energy supply for the facilities will be mixed: photovoltaic and grid electricity, which reduces the operational carbon footprint of the system.

The EIA establishes two important limits that the promoter must keep in mind:

• It does not exempt obtaining the remaining sectoral authorizations necessary to execute the project.
• It does not cover future decommissioning of the facilities, which will require a specific environmental assessment at that time.

Economic and operational impact

For MITECO as promoter, the favorable EIA is a critical milestone in the project timeline, but not the last. From now on, procedures must be activated for pending sectoral authorizations (water concession, urban planning licenses, authorizations from the Segura River Basin Authority, among others). Each pending authorization represents additional time and cost before construction can begin.

For farmers in the Campo de Cartagena, the continuous extraction of 35 l/s from the quaternary aquifer is the most relevant operational data: it implies a sustained reduction in the nitrate load reaching the Mar Menor, which can influence restrictions on the use of nitrogen fertilizers affecting the area under the vulnerable zone regulations for nitrate pollution.

For the municipalities of Cartagena and Los Alcázares, the approval of the EIA opens the door to the execution of infrastructure that will improve the water quality of the Mar Menor, with direct impact on the tourism sector and the image of the lagoon as a destination.

The mixed energy model (photovoltaic + grid) reduces long-term operational costs compared to a facility 100% dependent on the electrical grid, although the detail of energy investment is not broken down in the resolution.

Who does it affect?

• MITECO: project promoter, responsible for obtaining pending sectoral authorizations and implementing EIA conditions.
• Cartagena City Council: municipality where the El Albujón action is located (33.44 ha), must coordinate licenses and land use.
• Los Alcázares City Council: municipality where the homonymous action is located (11.41 ha), same coordination required.
• Farmers in the Campo de Cartagena: aquifer extraction and nitrate reduction can influence conditions for agricultural use of groundwater and fertilization restrictions.
• Segura River Basin Authority: must grant the water concession for continuous pumping of 35 l/s.
• Mar Menor tourism sector: improved water quality has direct impact on the economic activity of the lagoon.
• Construction and environmental engineering companies: the favorable EIA opens the way to bidding for works.

Practical example

Imagine an agricultural company with operations in the Campo de Cartagena that draws water from the quaternary aquifer for irrigation. With continuous pumping of 35 l/s destined for the green filters, pressure on the aquifer increases. If the company has its own extraction concessions, it must verify with the Segura River Basin Authority that its extraction rights are not affected by the new concession that MITECO must request.

At the same time, if the system's efficiency reaches 97.5% in nitrate removal, the nitrate load reaching the Mar Menor from El Albujón will be drastically reduced. This could translate into a review of fertilization restrictions in the vulnerable zone, which in the medium term could benefit farmers with greater flexibility in the use of nitrogen fertilizers, although that process depends on subsequent administrative decisions not covered in this resolution.

What should companies do now?

1. MITECO and project teams: immediately activate procedures for pending sectoral authorizations (water concession with the Segura River Basin Authority, urban planning licenses in Cartagena and Los Alcázares, photovoltaic facility authorizations). The EIA is favorable but does not replace any of these.
2. Farmers with concessions in the quaternary aquifer: review their concession titles and consult with the Segura River Basin Authority if the new pumping of 35 l/s may affect their extraction rights.
3. Cartagena and Los Alcázares city councils: prepare urban planning license procedures and coordination with MITECO to expedite execution once sectoral authorizations are obtained.
4. Construction and environmental engineering companies: monitor the publication of bids associated with the project, as the favorable EIA is the step prior to contracting works.
5. All affected parties: keep in mind that future decommissioning of the facilities will require a specific environmental assessment, so any long-term planning must contemplate that additional procedure.

Official source

Consult complete regulation at official source

Notice: This article is purely informational in nature and does not constitute legal advice. For specific decisions, consult a qualified professional. Source: https://www.boe.es/diario_boe/txt.php?id=BOE-A-2026-19403