At Aspendos, an inverse syphon technique is used to take the water across the low-lying valley of the Eurymedon between two high hills. Pressurization is therefore required as a substitute. The latter is set at a slightly lower level than the former, and is an open tank to aid settlement and get rid of bubbles. The water can then be distributed on its way. Those towers each contain an inspection staircase giving access to the settlement tanks on top, which are necessary in order to allow air to escape after restriction in the closed, interlocking pipes, and thereby reduce friction.
Wonderful views are to be had from the top.
One persuasive indication of the prestige involved in water delivery, and the conspicuous consumption essential to impress visitors, is seen in the development of monumental nymphaea - that is, fountain basins backed by architecture and sculpture, often depicting those nymphs who were supposed to be the denizens of such running water. At Miletus, for example, the great basin is flanked by double-storeyed colonnaded wings, and backed by three storeys of niches, nine per storey, each niche containing a statue, and alternate niches set in an aedicule. There are no fewer than twenty-seven statues in all, and the lowest rank pour water into the basin from the vessel they hold. All seem to have been decorated with architectural motifs and statuary.