Water Quality and Hydromorphological Variability in Greek Rivers: A Nationwide Assessment with Implications for Management

Stefanidis Stefanidis,Markogianni Markogianni,Dimitriou Dimitriou,Papaioannou Papaioannou

doi:10.3390/w11081680

Stefanidis Stefanidis, Markogianni Markogianni + Show 2 more

Open Access

https://doi.org/10.3390/w11081680

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Journal: Water	Publication Date: Aug 13, 2019
Citations: 22	License type: CC BY 4.0

Affiliation: Hellenic Centre for Marine Research

Abstract

European rivers are under ecological threat by a variety of stressors. Nutrient pollution, soil erosion, and alteration in hydrology are considered the most common problems that riverine ecosystems are facing today. Not surprisingly, river monitoring activities in Europe have been intensified during the last few years to fulfil the Water Framework Directive (WFD) requirements. With this article, we present a nationwide assessment of the water quality and hydromorphological variability in Greek Rivers based on the results of the national monitoring program under the WFD. Water quality and hydromorphological data from 352 sites belonging to 221 rivers were explored with principal component analysis (PCA) to identify main environmental gradients and the variables that contribute the most to the total variance. Nitrate, phosphate, ammonium and electrical conductivity were identified as the most important water chemistry parameters, and typical vector-based spatial data analysis was applied to map their spatial distribution at sub-basin scale. In addition, we conducted simple linear models between the aforementioned parameters and the share of land uses within the basin of each sampling site in order to identify significant relationships. Agriculture was the most important land use affecting the nitrate and electrical conductivity, while artificial surfaces were the best predictor for phosphate and ammonium. Concerning the hydromorphological variability, fine types of substrate and discharge were the variables with the highest contribution to the total variance. Overall, the results of this article can be used for the preliminary assessment of susceptible areas/rivers to high levels of nutrient pollution that can aid water managers to formulate recommendations for improvement of further monitoring activities. Furthermore, our findings implicate the need for enhancement of agri-environmental measures and reduction of point-source pollution in disturbed areas to avert the risk of further environmental degradation under the anticipated global change.

Highlights

The Directive 2000/60/EC established a framework for Community action in the field of water policy and set the objectives to prevent further status deterioration of all Community waters—rivers, lakes, coastal waters, and groundwaters—in order to achieve and maintain their good status by2015 [1,2], which was extended from 2015 to 2021 and from 2021 to 2027 [3]
The coverage of the sampling network extends to the whole national territory and is distributed among fourteen Water Framework Directive (WFD) River Basin Districts (RBDs) (Table 1, Figure 1)
Concerning the hydromorphological variability, our results showed that the first component represents a gradient of substrates that are related with higher cover of channel vegetation, while PC2 indicates a gradient of deeper, larger river reaches with larger quantity of water

Summary

Introduction

The Directive 2000/60/EC established a framework for Community action in the field of water policy and set the objectives to prevent further status deterioration of all Community waters—rivers, lakes, coastal waters, and groundwaters—in order to achieve and maintain their good status by2015 [1,2], which was extended from 2015 to 2021 and from 2021 to 2027 [3]. The Directive 2000/60/EC established a framework for Community action in the field of water policy and set the objectives to prevent further status deterioration of all Community waters—rivers, lakes, coastal waters, and groundwaters—in order to achieve and maintain their good status by. Some of the main objectives of the Water Framework Directive (WFD), except for the achievement of good status, include the provision of an integrated water management system based on hydrological catchments, bringing together economic and ecological perspectives (Art. 3) [3], the involvement of active stakeholders and the public (Art. 14), and the introduction of a combined approach to pollution control (Art. 10) [2]. The implementation of the WFD relies on the measures proposed by the River Basin Management.

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