Representation of the operation of ancient hydraulic works in Kopais area

The drainage of Lake Copais (in the centre of Boeotia, Greece) has always been an issue of great importance for the inhabitants of the surrounding area, as if this was accomplished about 25.000 ha of fertile land would be available for cultivation. The Modern Greek Nation achieved to complete this project in 1931, after more than 100 years of efforts. The first documented successful attempt to drain Lake Copais is attributed to the Minyans (the Mycenaean inhabitants of Orchomenos) during the 2nd millennium BC. The Minyans led the main rivers that flooded Copais (Boeotian Kephisos and Melanas) to the natural sinkholes of the northeast edge of the basin, building large levees and strong retaining walls with a total length of about 20 km. The water was sunk into the sinkholes (underground crevices and tunnels in limestone) and reappeared at the North Euboean Gulf. These works had an instant impact on Copais, converting it to a large plain whose cultivation made the Minyans one of the wealthiest ancient civilizations. Although the impressive ancient drainage system of Copais has been extensively studied by archaeologists and engineers (such as Knauss, Kambanis, Kenney etc) many questions still remain unanswered regarding the way it worked. The scope of this diploma thesis is to provide some reliable possible answers to these questions by studying several aspects of the ancient Minyan works from the view of a hydraulics engineer. In order to achieve this, we try to quantify the most important hydraulic components of Copais area (discharge of the main rivers and torrents, precipitation, evaporation) and its hydrogeological characteristics (discharge of the katavothres) while we also try to estimate approximately the water needs of Minyans (urban water use, water for crops irrigation). The results of the hydraulic analysis combined with the archaeological findings (positions and dimensions of flood protection works, materials that were used by the Minyans, construction techniques) and the information that is provided by relevant existing studies, allow us to draw some important conclusions about the ancient hydraulic works of Copais and develop a fairly complete scenario about the purposes they served and the way they worked.