Investigation of groundwater inflow into dewatering tunnels. the case of Hadrianic aqueduct

Since antiquity, in areas with semi-arid climates which suffered from a lack of surface water, there has been a need to exploit groundwater aquifers. For this reason, in additions to wells, dewatering tunnels began to be built. The first to be constructed were the Qanat, which started in Persia and spread to many parts of the world, and the Puquios, located in the Rio Grande de Nazca River Basin in Peru. Their main function is to collect groundwater and transport it with the force of gravity to residential and irrigated areas downstream. The technique of dewatering tunnels has been widespread since antiquity in various parts of the world, but technical information on the operation and efficiency of these projects is limited. The present study investigates the issue of groundwater flow towards dewatering tunnels, examining the quantities that infiltrate in relation to the technical characteristics of the tunnel and the physiological characteristics of the aquifer. For this purpose, analytical solutions are used as well as the SEEP/W software, for various shapes and rates of filling of the cross section of the tunnel with water. The case of the Hadrian's Aqueduct of Athens is being considered as a case study. After presenting its current condition, an extensive description of the geology and hydrogeology of the area is conducted in order to assess the quantity of water that infiltrates. Finally, the field measurements carried out at the Hadrian's Aqueduct are presented in order to investigate its operation and to estimate the discharge in some sections of it.