Explain the process for establishing the line and grade for a sanitary sewer line connection to an existing municipal sanitary manhole.

Explain the process for establishing the line and grade for a sanitary sewer line connection to an existing municipal sanitary manhole. Include the type of sewer flow, the importance of the pipe invert and reach of the sewer in determining the slope of the pipe, factors that determine the use of manholes, the use of batter boards and offset stakes, minimum ground cover required. In addition, discuss the use of visual aid such as field notes and a simple plan and profile drawing in establishing the line and grade.