Rivers are an essential component for ecosystems

and the health and survival of billions of people. The increasing water demand for drinking, agricultural, industrial and recreational purposes, imposes significant stress on the available water resources and urges the need for sustainable management.

River waters are the result

of a mixing between a precipitation and a groundwater component, through baseflow, and the recipients of contaminants such as nitrate ions (NO3). The relative contribution of each component depends on the topographical, hydrological, and meteorological characteristics of the catchment and on local land-uses.

Isotope hydrology techniques

(e.g., δ18Ο and δ2Η of H2O) constitute a powerful tool to decipher the interactions between river water systems, the atmosphere and groundwater and quantify their relative contribution, to estimate the mean residence time of stream water in catchments, and eventually to better understand the conceptual model of catchment areas.

Moreover, nitrate isotope (δ15N and δ18O of NO3) techniques have been proved to be a reliable tool to identify the dominant pollution sources (e.g., fertilizers, inefficient urban waste treatment, disposal of industrial effluents and unsustainable livestock breeding) and the associated biogeochemical changes (e.g., nitrification, denitrification) over time and space, which is the first and most important step for understanding Nitrogen dynamics in river catchments.

Efficient and continuous monitoring of river catchments is a necessary task for designing and applying management and mitigation measures to ensure long-term protection of the water resources.

Actions

Monitoring of the National Network of Isotopes in Rivers in Greece

Understanding water dynamics and pollution stresses in river catchments is a necessary task for managing efficiently water resources and provide appropriate mitigation and remediation measures.

Assessment of water dynamics in Schinias-Marathon coastal wetland and its implications to the local ecosystem

Coastal wetlands are vital for provision of a wide range of ecosystem services, including the support of fauna biodiversity, and thus the protection and the proper management of water resources is crucial for their sustainability.

Tracing nitrate sources of pollution in the urbanized catchment of Kifissos River

River waters flowing in urban catchments are susceptible to water quality degradation due to multiple contamination sources. The Kifissos River is an urban river that belongs in a catchment in the western part of Athens metropolitan area.

Assessment of the ecological role, functioning and biodiversity values of rivers/streams that flow in Prespa Lakes

The Prespa Lakes (Great and Small Prespa Lakes) are a group of freshwater lakes located in the southwestern part of the Balkan Peninsula undergoing water level decrease since the 1990’s and thus understanding of the hydrological systems’ dynamics is of major importance.