In ground fire hydrants are common in a number of countries, including the United Kingdom, Ireland and Australia.
For in ground hydrants, a pit is prepared. Some sort of open top and bottom box or frame typically is placed in the pit and around the hydrant. A top (usually a steel or reinforced plastic plate) extends over the box and can be hinged or otherwise connected to or supported by the top of the box or frame.
A disadvantage is that, over time, the pit fills with slime, mud, debris, soil, tree roots, insect nests and the like. Snakes are a safety concern as well. When urgently required, the hydrant outlet may be so buried in debris or clogged by nest material that coupling a fire hose to the hydrant becomes difficult and time consuming.
There would be an advantage if it were possible to better protect the hydrant from debris but in a manner where the hydrant would still be readily available if required, and in a manner that could be easily and reliably achieved.