Between 1980 and 1992, a number of excavations have encountered various excerpts of the western and southern ditch sections providing us with insights to its construction and use (Panhuysen 1996). For example, the 1980 excavation of the western side of the Havenstraat established that the ditch was constructed six meters away from the stone walls and that it was approximately nine meters wide and 3.80 meters deep. Based on computer measurements and calculations, Wetzels (2017) hypothesises that the soil removed to make the ditch/moat was at least partially used to level out the inner portion of the castellum as well as to enlarge and strengthen the western bank of the Meuse River.
It was during the 1992 excavation at the Wolfstraat 15-17/Havenstraat 4 site which revealed two 4th century phases of use – the first includes its initial construction and maintenance from c. 333–350 CE and a second phase between c. 350 and 390 CE in which the ditch was allowed to be silted up. There was a temporary restoration of the moat around c. 390 but by c. 450 CE the ditch was filled in.