What is meant by the term "base" in the context of a manhole?

In the context of a manhole, the term "base" refers specifically to the bottom part of the manhole structure. This is an essential component because it typically serves as the foundation for the manhole and is responsible for supporting the sides and the cover of the manhole. The base is designed to handle the weight and pressure above it, ensuring structural integrity and stability.

Understanding the role of the base is crucial for maintenance and construction within collection systems, as problems with the base can lead to issues such as leaks or structural failure. Therefore, recognizing that the base is the lowest portion of the manhole structure is fundamental in the study of collection systems and their maintenance practices.