Выходы подземных коммуникаций даются в виде колодцев, камер,
коверов.
Quality Level C (QL-C) uses any available information from QL-D and correlates it with surface features. These features may be ACCESS POINTS on the surface such as hydrants, stop valves, access chamber lids, or POINTS WHERE UTILITIES ENTER the SUBSURFACE DOMAIN (e.g. an electricity cable travels down a power pole and then becomes a subsurface electrical cable). Источник: Implementing the Australian Standard for Subsurface Utility Information – AS5488 - https://www.apas.org.au/files/conferences/2014/Implementing-...–AS5488.pdf

По-видимому, здесь имеется в виду, что съемка подземных коммуникаций выполнена в процессе топографической съемки по внешним признакам, по выходам на поверхность земли (смотровым колодцам-люкам).

В договорной документации часто встречаются и такие словосочетания, как subsurface utility features. Например, For the purpose of this agreement, “Sanitary Sewer Mapping” means to indicate the presence and approximate
horizontal and vertical location of underground utilities by surveying visible above-ground and ACCESSIBLE subsurface utility FEATURES, such as manholes, pipe inverts, etc. and by using professional judgment, correlating this information with existing utility records.

Также пишут и более развернуто: subsurface utility features visible at the ground level. Например, All surveys shall include (in addition to subsurface utility features visible at the ground level): determination of invert elevations of any manholes and vaults; sketches showing interior dimensions and line connections of such manholes and faults; any surface markings denoting subsurface utilities furnished by utility owners for design purposes.