The Region of Central Macedonia (Figure 5) is one of the thirteen administrative districts of Greece. It is situated in Central Northern Greece. It is divided in seven prefectures (Prefecture of Thessaloniki, Imathia, Kilkis, Pieria, Serres, Pella and Chalkidiki). It covers an area of 19,147 km2 (14.51% of the country), thus being the largest district in the country.
The borders of the Region of Central Macedonia are the Region of Western Macedonia in the west, the Region of Eastern Macedonia in the east and the Aegean Sea in the south and FYROM Republic and Bulgaria in the north.
The population of the Region of Central Macedonia is 1,710,513 inhabitants [population census of 1991, National Statistical Service of Greece], and is equal to 16.67% of the Greek population, putting Central Macedonia in the second place among the districts of Greece, regarding population numbers. Population density is thus 89 inhabitants per Km2.
The city of Thessaloniki is the center of the Region of Central Macedonia. The Urban Agglomeration of Thessaloniki is the second biggest and densely populated agglomeration in Greece, with more than one million inhabitants.
Central Macedonia Region comprises two Water districts the central Macedonia and eastern Macedonia water districts.
This district is characterised by extended planes lying at the western part of the district. These areas cover 4000 Km2, which is the 36% of the Region. At the borders of the area occur also low mountains. Only the 15% of the district is over the 1000 m. There occur 9 mountain chains; the higher of these are Kerkini (2031m) to the east and Athos (2033 m) to the south. The most important planes are those of Gianitsa, Thessaloniki, Langada and Chalkidiki. The mean altitude of the district is 195 m.
Landscape in this district is more flat due to the great extend of valleys. Mountainous areas occur to the north, east, west and central areas. The higher mountains are Kerkini (2031 m) to the west, Orvilos (2212 m) at the centre and Falakro (2111 m) to the east. West of the district lies the plaen area of Strymonas river and Serres basin, whereas to the east the Drama basin.
The mean altitude of the district is 166 m.
From the geotectonic point of view at the district the Servo-Macedonian and Circum Rhodopic zones, as well as the Axios Ophiolitic zone are outcropped in a northwest – southeast direction.
More specific the geological formations occurring at the district are:
At the district rocks of Rhodope massif and Servo-Macedonian zone develop at the northwest – southeast direction separated by the Strymonas River valley.
Pageon and Sidironero units constitute Rhodope massif, whereas Kerdilia and Vertiskos units the Servo-Macedonian zone.
Petrologicaly, these units mainly comprise of amphibolites, gneisses, mica schists and marbles (old basement), whereas, metamorphic rocks of the Ohpiolitic massif as well as Mesozoic (Vertiskos) and Tertiary (Vrontou) igneous rocks are also present. Eocene- Oligocene mollase sediments, Miocene – Pliocene – Pleistocene sediments and alluvium deposits occur at the Strymonas valley and Phillipoi area.
In central Macedonia Region many important ecotops, wetlands and other sensitive areas occur protected by International, European and National laws and agreements. The most important wetlands of the Region are: