Supervisors info:
Δρ. Χαρίκλεια Σκυλοδήμου, ΕΔΙΠ, Τμήμα Γεωλογίας, Πανεπιστήμιο Πατρών
Summary:
A hydrological network is a network for transporting the surface water and sediments of a defined topographic unit, the catchment, i.e. the surface of the bare land draining it. Land use is the term representing areas used for residential, industrial, commercial, agricultural, forestry, and recreational or conservation purposes.
The study area of the thesis is the wider area of Nea Makri, where the settlements of Neos Voutzas, Mati, Kokkinos Limanaki, Agia Marina, Vithinia, Agios Andreas and Zouberi are included, in which the seasonal flow hydrographic network will be studied. The aim of this thesis is to map and analyse the hydrographic network and draw conclusions taking into account land use changes.
The topographic charts 6447/5, 6447/6, 6447/7, 6447/8 at a scale of 1:5.000 of the Geographical Service of the Army as well as the geological map at a scale of 1:50.000, Kifissia of the Institute of Geological and Mineral Exploration (IGME) were used for the mapping of the hydrographic network. The total length of the hydrographic networks of the study area have a magnitude of 53 km length. Geotagged photographs were taken, while using GPS for verification as well as observations in the field. A division of the study area into watersheds was carried out and these were numbered in sequential order North to South. Using Geographic Information Systems (GIS), the hydrographic networks of the study area were digitized. The categorization of hydrographic networks into I, II, II and IV classes of order (Strahler 1956). By using and processing the database "Urban Atlas" of the European Copernicus service, conclusions were drawn on land use changes in the study area for the years 2006, 2012 and 2018. This database also includes the major fire in Matti, Attica in the year 2018. These factors were intercorrelated and the following results were extracted:
A total of 12 catchments with their respective hydrographic networks were recorded in the study area. In the whole study area, 129 first order sectors, 33 second order sectors, 7 third order sectors and one fourth order sector were measured. In the study area 48.5% of the valleys in the hydrographic network are free, 20.5% show some form of settlement and 31% are completely covered.
In the first catchment area it is observed that the impact of the fire was the smallest of all the others in terms of area as it burned an area of 347,008 square meters which corresponds to 11.6% of the total area of the catchment area. In the second watershed the 2006 and 2012 land use records for forests and natural areas captured areas of 785,102 square meters, with the 2018 fire destroying areas corresponding to 274,155 square meters.
The fourth and sixth watersheds show the greatest land use changes, while the fifth and sixth watersheds show the greatest coverage of the hydrographic network.
In the third watershed it is observed that the impact of fire was the most notable as it is the largest land use in 2018. This can be observed as an area of 1.97 square kilometers was burnt which corresponds to 72.7% of the total area of the watershed.
In the fourth watershed it can be observed that the effect of fire was the most devastating as areas of 1.59 square kilometers which corresponds to 92% of the total area of the watershed were burnt.
In the fifth catchment the low-density urban tissue with land sealing less than 50% in the 2006 and 2012 records remains unchanged with the 2018 fire destroying more than 2/3 of the area of this land use.
In the sixth and seventh catchments, areas of 1.2 and 0.1 square kilometers respectively were burnt, significantly reducing the urban fabric.
In the eighth catchment area, three quarters of the urban fabric was destroyed, with a burnt area of 1.2 square kilometers.
In the ninth, tenth, eleventh and twelfth catchments the dominant land use is the burnt areas of the 2018 fire which destroyed 2/3 of the urban fabric while sports and recreation facilities were completely destroyed.
The hydrographic network of the sixth catchment is the one with the highest percentage of coverage by human intervention, it is the only one with a class IV hydrographic network branch as well as 86% of its total area is dominated by burnt land. In the study area, it is observed that the residential fabric and the infrastructure that has been rebuilt on most of the land interferes with the natural flow of the hydrographic networks.
