Jerwan Aqueduct

The overall height of the aqueduct has been estimated to be about 9 m and its width about 22 m (not including the buttresses). Its total length will have been more than 280 m, thus involving a great mass of masonry. The ashlar blocks from which the aqueduct was constructed are all massive, though they vary in size. At the upper levels, they are 40 cm in height and 50 cm in length and width. Lower down, the blocks are larger, measuring 1 x 1 m and 70 cm high. It appears that the facing stones were worked in situ, given the deep layer of stone chips found at the foot of each façade. This is also suggested by the fact that the mason in many cases adjusted the face of the stone to that of the neighboring one only along the joints and left a rough projecting mass in the middle, thus giving the appearance of intentional rustication.

Archaeological excavations conducted at the site show that the building process began with the leveling of the terrain in preparation for the aqueduct's foundations. A rectangular bed of rough boulders was laid just beneath the level of the stream. These boulders were covered by a pavement of large stones, laid diagonally to the flow of the stream in order to increase their stability; from this level, the piers rose. The aqueduct’s façades are divided by projecting buttresses into fourteen bays. A large central bay contained the five pointed arches that spanned the ravine; the remains of the two westernmost arches—preserved up to six courses high—reveal that they were constructed using the corbeling technique.

In the vicinity of the archways, archaeologists discovered a group of five stepped stones in varying states of preservation. Although their original location is unknown, they seem to have formed one unit of stepped battlement of the type familiar in Assyrian architecture. One of the stones was stepped on one side only, suggesting that it might have belonged at the end of a row. 

The masonry was built solid from the foundation up to a point slightly below the canal level, where a layer of concrete was spread about 40 cm deep. Over this was bedded a carefully graded stone pavement flanked by a parapet. The concrete does not extend beyond the inner face of the parapet on either side, and the builders made sure to avoid a straight joint between the parapet and the pavement; this precaution will have been taken to prevent the constant weight of the parapet and the varying weight of the water from causing a crack in the concrete, resulting in leakage. In addition, a tilting course was used along the base of the parapet that might have been designed for occasions when the aqueduct was not in use, thus preventing water from collecting and standing at critical points.