Filling the ponds of Hattuşa - a geohydrological approach to determine inflows by time and volume

Abstract In the ruins of Hattuşa, the capital of the Hittite Empire more than 3,000 years ago, large, sedimented water storage ponds have been uncovered since 1998. An investigation based on time series of measured groundwater levels, showed that the ponds were supplied from layered aquifers which were opened at their source horizons directly at the uphill edge of the pond. When the groundwater level at the pond exceeds a threshold given by the geology at that edge, water pours into the pond. The principles and the path of filling become clear, but not the volumes and time distribution of the transfers. These results of the previous studies were amply published and are shortly summarized. The present investigation is also based on the time series of groundwater levels and of the discharge of a modern fountain as well as the local hydrogeological properties. The approach is simple but shows the effect of storage in the aquifer which delays the outflow into the pond, so that water from the rainy season was available in the dry season. Also, the annual outflow values are determined. Besides gaining knowledge it is an aim of the article to encourage interdisciplinary and process-oriented thinking.