Fulling is a step in woolen clothmaking which involves the cleansing of cloth (particularly wool) to get rid of oils, dirt, and other impurities, and thickening it. In Roman times, fulling was conducted by slaves standing ankle deep in tubs of human urine and cloth. Urine was so important to the fulling business that urine was taxed. Urine (known as 'wash') was a source of ammonium salts, and assisted in cleansing the cloth. So clearly this was an industry that the city of Antioch preferred to keep at a distance. Moreover it was one that was undesirable to have on the banks of the Orontes where it ran through the city.
We have noted before that there is little new under the sun since the 1930s in hard evidence on the subject of Antioch. However, the discovery that threw up the existence of this canal was the unearthing of two limestone stelae on the west bank of the river. The two stelae recorded the benefactors (some willing, some levied) to the project and what a substantial project it was. It is estimated by Denis Feissel, the main scholar to examine these inscriptions, that the canal was 14 stades (8,200 feet) in length and that it was doled out in 720 feet lots to different "blocks" of the city to build (i.e. labour levies). This is certainly a massive undertaking which suggests that fulling was a very substantial industry in the city/neighbourhood. Until now, the impression one has of Antioch is of perfumers and other luxury artisans being the city's core business. In some ways an ancient version of Paris's current status. However, expending such a massive effort on a very substantial canal indicates that fulling (and the other textile processes associated with it) must have been very big business.
The two stelae were very similar with the first 29 lines of stele A being the same as the first 25 lines of stele B. The subsequent lines listed "donors" and patrons of the project. Each stele related to one of the tranches of the canal. It is somewhat miraculous that two should have been found.
Here is the text of stele A:
"Under Imperator | Titus Flavius C|aesar Augustus | and Imperator || Titus Caesar and | Domitianus Caes|ar, sons of Augustus | work on a fuller’s canal | and barriers || that diverted | the same watercourse | authorized by Marc|us Ulpius Traianus the le|gate of Caesar Augustus || was performed by the me|tropolis of Antioch | block by block | in the year 122 (AD73-74). From the Orontes | up to the opening at the foot of | (Mt) Ama||nus [it is 14 stades] | in length and  1 square feet |(in width and depth). [Equal]| distribution of the work was made among the blocks | based on the proportion of the ||number of people (in them) and on their length | width and depth in accordance with which| each block was made responsible| for its own proper place| for the delivery (of the work).
There are on || this stele the remainder| of the people (of the block) of the high priest Damas| (responsible for) 33 ½ (and) ¼ in length (the block) of Bragates | 38 ¼ in length; (the block) of Pharnakes the former gymnasi|arch, 69 feet in length (the block) of Artas || son of Thrasydemos, 25 ½ feet in length; (etc.)"
No trace of this canal has been found, but then again no-one has been looking. We presume that it separated from the main channel above the city and then reconnected (Poccardi speculates via a lock) below the Bridge Gate thus spilling the pollutants downstream form the city. The moving meanders of the river over the milennia have erased the entry to the canal but some determined searching may turn up the lock below the city or at least some point of reconnection.
One aspect of the translation of the stelae that intrigues me is the reference to the "blocks". Feissel claims that the project must have been in twelve sections to make up the 14 stades. It is not clear if Feissel knew of the phylae system of the city (which we discuss elsewhere). It would appear more logical to us that the phylae (of which there were 18) were levied to make their contribution to this engineering undertaking rather than individual city "blocks". We have, as yet, been unable to find a definitive enumeration to the names of the phylae (though a listing is supposed to exist in Ritter's Erdkunde, which we have been unable to track down).