Case study 3
The Kifissos basin and the underlying Aquifer system in Athens metropolitan area faces complex environmental challenges, primarily due to : (a) intermittent stream flows resulting from infrequent rainfall; (b) human interventions further complicate the hydrographic network and the flood generation mechanism; (c) stormwater runoff during storms and flash floods along with urban land use degrades the urban aquifer system, impacting both ecosystems and coastal environments; (d) elevated contaminant levels that pose a significant water quality issue ; and (e) a heavy contaminant load into the marine environment though diffuse and point ground/surface water discharge into the Mediterranean Sea. In the UPWATER project, we aim to enhance understanding of pollutant sources as well as their fate and transport, improve surface and groundwater quality, and identify new water uses dependent on local groundwater resources. Innovative, nature-based solutions will be explored in Athens, focusing on monitoring, mitigation, and prevention methods.
- National Technical University of Athens (NTUA), Greece
- Athens Water Supply and Sewerage Company (EYDAP), Greece
Environmental characteristics
In Athens metropolitan area, Kifissos river stands as the primary surface watercourse discharging into the sea. The river has ephemeral flow due to sporadic precipitation, a characteristic commonly observed in arid and semi-arid regions. The intricate hydrographic network has evolved through substantial human interventions, including channel modifications and the construction of underground waterways. These artificial alterations intricately interconnect with the broader natural waterworks system, ultimately leading to the Mediterranean Sea. Underneath the urban landscape of the metropolitan city, the geophysical system is a complex, multi-layered, unconsolidated and sedimentary aquifer. Additionally, the hydro-system encompasses various karstic aquifers encircling the urban area, contributing to the unconsolidated aquifer through lateral recharge.
Main challenges
One of the main challenges associated with the water quality in Athens is the presence of elevated concentrations of Contaminants of Emerging Concern (CEC), nitrogen compounds, and heavy metals. This issue is further compounded by the predominant use of water for urban landscaping irrigation, necessitating the reduction of pollutants in the water. Additionally, during storms and flash floods, stormwater runoff of compromised quality serves as a contaminant source for various ecosystems, resulting in the degradation of the urban aquifer system and the unsaturated zone. Furthermore, this water discharge negatively impacts the coastal marine environment at the Kifissos estuary.
What we aim to achieve
In the UPWATER project, Athens aims to identify and quantify various pollutants (contaminants of emerging concern) in groundwater that mainly originate from several sources related to urban land use , similar to the other two case studies in Stengaarden and Barcelona. Enhancing the knowledge of those pollutant sources and their pathways will help to avoid the contamination of the groundwater.
Collaboration between the project partners and stakeholders is very important to achieve this goal. Together, they will provide feasible and sustainable solutions on groundwater and surface water deterioration management. The stakeholders will support groundwater modelling scenarios generation through a participatory approach, along with UPWATER researchers.
Last, the project partners will identify all existing and possible new water uses that depend on the local groundwater resources. Examples of water used are the irrigation of municipal landscaping, private wells and industrial needs. This is necessary in order to validate Nature-Based Solutions (NBS) that improve the water quality to the required standards. Solutions that preferably integrate seamlessly with the natural area itself. When solutions have proven to be useful, they could be scaled up in the Athens region and other areas facing similar water challenges.
Innovative methods in this case study
- Passive sampling methods
– Ceramic passive sampler (CPS)
– Viral passive samplers (VPS)
– Diffusive gradients in thin films (DGT) - Natural Based Solutions (NBS) on CECs and other pollutants treatment
– Floating wetlands
– Biochar treatment technologies
– Soil Aquifer Treatment (SAT) technologies
Are you interested in delving deeper into the methodologies employed in the Athens case study, or the methods employed in the other UPWATER case studies? For more detailed information, please continue reading on the dedicated methods page.