Along a hollow southeast of the Southern Citadel the Hittites fashioned two small artificial lakes, the extent of which is indicated by the reinforced sloping banks which have been restored (and partially reconstructed) here. Pond 1 measures about 60 x 90 m. Although only the northern edges of Pond 2, lying behind it to the southeast, were excavated, the lay of the land here indicates that it could not have been much smaller. A dam, 16 m across at the base, separated the two, and similar constructions were used to reinforce the NE banks of both ponds and the NW bank of Pond 1.
The edges of the basins were formed by shallow sloping embankments cobbled with limestone. The bottom of the ponds, rather than being paved, were simply plastered with a watertight layer of clay; the underlying rock is serpentine, which permits only minimal seepage.
Insulating the paved embankments proved much more of a challenge, and here the Hittite engineers came up with a rather ingenious solution. Deep, narrow trenches were opened behind the embankments and filled with watertight clay, thus minimizing the seepage.
Several springs fed the ponds. One of these, above the street, still flows year round. Because still more water was necessary, however, a system of clay pipes was installed to bring in water from springs outside the city, and a pipeline passes through the city walls below the King's Gate for this purpose.