Appears to be a drain. Similar construction technique (simple ditch edged and filled with with stone and tile) to drains found in Areas 20000, 15000, 13000, 11000. No datable evidence in fill of feature. Hard to determine phase; it seems constructed over 17190, which continues underneath, and may cut end of wall 17020, explaining why south end of wall is missing its end pier that were found on other opus ret. walls (e.g. 17002). But also seems to be under the collapse, and so may represent a drain built when the blacksmith workshop was installed in the complex and may be associated with metalworking activities. This area disturbed by 2017 excavations.