Εκτίμηση Οικολογικής Παροχής στον Ταμιευτήρα του Μαραθώνα. Διαχείριση και Αξιοποίηση.

Περίληψη

Η οικολογική παροχή αποτελεί την ποσότητα ροής ύδατος που διατίθεται για την αποκατάσταση και συντήρηση των διεργασιών που συντελούνται σε ένα ποτάμιο σύστημα, προς όφελος της διατήρησης των υδρόβιων οικοσυστημάτων, όταν η ανθρώπινη παρέμβαση οδηγεί στη ραγδαία μεταβολή της υδρολογικής ροής. Αντικείμενο της παρούσας εργασίας είναι η μελέτη εκτίμησης της ελάχιστης οικολογικής παροχής που δύναται να διατεθεί από ένα φ ράγμα, κ αθώς κ αι ο ι δ υνατότητες δ ιαχείρισης κ αι α ξιοποίησης τ ης. Η μ ελέτη περίπτωσης που επιλέγεται είναι ο ταμιευτήρας του Μαραθώνα στην Ανατολική Αττική, για τον οποίο δεν είχε προβλεφθεί η διάθεση οικολογικής παροχής κατά την κατασκευή του. The environmental water flow represents the amount of water provided within a river system, with a view to maintaining the freshwater ecosystems and their functionality, when human intervention results to the vast regulation of the flow. The need to estimate and provide environmental flow is caused by the growing demand for water resources and the subsequent degradation of the downstream river systems. The purpose of this study is the assessment of the appropriate amount of environmental flow that can be provided from a dam as well as the sustainable management of the proposed flow. The case study, which is selected, is the Marathon dam located in the northeast of Athens in Greece, at the junction of Charadros river and Varnavas stream. During the construction of this dam (1926-1929) there was not any consideration over the need to establish ecological flow. The methodologies and tools, which are applied to address the environmental flow needs, are based on hydrological indices, using the historical monthly and daily flow records. By taking into account the current functions of the Marathon reservoir and the minimum requirements of the existing legislation, the methodologies used provide an estimation of the minimum required flow needed to preserve the downstream ecosystems. The second part of the study emphasizes the subject of the environmental flow implementation and discusses suitable proposals for the optimal exploitation of the estimated flow. It is believed that the water flow should be used for the augmentation of the underground resources due to the depletion of the ground-water aquifers. The method used, requires the evaluation of the land topography, the downstream hydrological network and the geological characteristics alongside the stream of the flow, in order to detect the appropriate positions for the effective application of the artificial recharge. At last, it is proposed that the excess of water is channeled to Schinias-Marathon National Park, utilizing the existing water network between the Park and the Marathon dam, thus contributing to the enhance of the water resources and the rejuvenation of the Park.