inspection well, observation well (wells in a pipeline to facilitate the inspection of the operation of the drain. ICID)
inspection pit (a pit excavated at the junction of a lateral and main drain; acts as a silt trap and is used to facilitate inspection of a composite tile drainage system. ICID)
manhole, sewerage manhole, inspection chamber (chamber entered via a hole through which a man may descend or creep into a drain, sewer, steam boiler, parts of machinery, etc., for cleaning or repairing)
monitoring well (IATE term note: bodemverontreiniging)
drainage channel
hatch-box, unblocking point (ontstoppingspunt/inspectieput)[L.B.Escritt, Water Supply and Building Sanitation]