Hydrological research of Hadrianic Aqueduct

The Hadrianic aqueduct is a monumental waterwork constructed during the period AD 125-140 by the Roman Emperor Hadrian and his successor Antoninus Pius. Hadrian, after conquering Athens, in order to meet the needs of the new Roman residents and to assimilate the Athenian population decided to build the aqueduct. The backbone of the aqueduct is 17,8 km long tunnel, the northern part of which is located in the foothills of Mount Parnitha, and ends near Saint Demetrius church at Ampelokipoi district. From this point on and beyond the next 2,2 km, the aqueduct continues as a underground closed conduit up to Lykavitos hill near the city of Athens, where the water ends up at a reservoir. The tunnel was constructed using the shafts and gallery technique. Every 35-40 m wells were dug along the aqueduct’s route, and when the digging reached the desired depth the worker started digging upstream to find the next well uphill and eventually connect the two wells. The water flowed down the tunnel and conduit by gravity up to the reservoir, in front of which a monumental façade was added. In antiquity and early 1900s lateral underground branches or streams supplied the aqueduct with additional water. In addition, the aqueduct is enriched by groundwater. Due to the physical attributes and characteristics of the rocks the tunnel penetrates, and the fact that the biggest part of the tunnel is under the water table, along its course the aqueduct collects underground water. The purpose of this diploma thesis is the hydrologic and hydrogeological research of Hadrianic aqueduct. More specifically it investigates the ground and underground water system of Kifisos basin, which is the aqueduct’s broader area of study, and the water basins of the lateral branches and streams. The aim is the understanding and representation of the functions of the aqueduct's underground aquatic system by quantifying the inputs and outputs of the system. The research is accomplished by analyzing and processing the geological and hydrological parameters of each water basin. Initially, the soil formations of each water basin were identified and then their physical attributes and characteristics were described extensively.The aim was to understand their hydrological behavior and ultimately to estimate the parameters of the program Zygos, which we would use to simulate the water basins. Following, from the rainfall network of the area, precipitation and potential evapotranspiration data were collected. In order to achieve the most realistic simulation possible, multiple runs were carried out using the Zygos model, testing different parameter values. Because the input variables are non-controlled by in situ measurements, for the final selection of the ´best estimate´ of the parameter values, the qualitative characteristics of the simulation concerning the plausibility of the parameters were taken into account. Six sets of parameters were selected from the results, and for each set, the values of surface runoff , real evapotranspiration, and underground flow were estimated for each water basin. Finally, conclusions are being made about the hydrological research, following recommendations for further research on the Hadrian Aqueduct.