we currently have found some old aqueduct under the site of 22 stories building. it cost very much to excavate and improve soil, because as GPR shows, aqueduct developed about 10 m in depth !! origin soil is very hard marl.
History often shows builders in early times knew things that we dont today. If the building has withstood the test of time, and with no signs of settling, that is a meaningful piece of evidence. Consultation with geologist, civil engineer and archeologist may be helpful.
I assume the aquaduct was constructed, and the hard marl that I am familiar with "appears", competent, but at some substantial distance from the area, is without marl, and there are sinkholes or limestone depressions. If the term aquaduct is something else that developed from underground flow, as soil piping or dissolution of karst materials in an underground stream or cave network, I would be concerned.
A geologist may help explain the landform and materials.