The purpose of a catch basin is to collect storm water to be transferred to an underground pipe system. They also allow human access to allow for inspection, cleaning, and maintenance of the underground piping system between the catch basins. Lastly they may also be collectors (sumped units) to keep sediement from travelling throughout the pipe runs and clogging the pipes requiring costly repairs, jetting, and vacuum services. The purpose of a manhole is similar to above only they don’t typically accept drainage and are utilized to be a junction when pipe line and grade changes must intersect. Catch basin and manhole designs have changed over the last 2-3 decades to implement a precast concrete design. The manner in which drainage structures were placed in the early 20th century involved brick or block and mortar walls which were built up in place.
While this was (and still is in some areas) an effective and durable long term solution, it has become somewhat outdated, costly, and not as effective as modern practices. For these reasons, and just simple age, it is often required that these catch basins (and in some cases newer precast catch basins) become removed, and in many cases replaced. Catch Basins are typically smashed and broken down with a backhoe or excavator, then removed from the hole. In some cases the old manhole is strong enough to be dug around and remove as one large mass. If a replacement catch basin is not taking the place of the old, and the old catch basin was under or near pavement, it will typically be required that the excavation be backfilled with aggregate stone and compacted so future settlement will not occur.