Section 620 - Surface and Sub-Surface Drainage Structures and Facilities
   Section 620.1 - Earthwork and Drainage
All necessary surface and sub-surface storm drainage structures and facilities shall conform to the R.I. Standard Specifications for Road and Bridge Construction. Such Standard Specifications may be modified at the discretion of the Planning Board.
   Section 620.2 - Storm Drain and Sanitary Sewer Manholes/Catch Basins
   A.   Catch basins shall be R.I. Standard 4.31 Type "R" or as directed by the Public Works Director. Storm Drain Manholes or Catch Basins shall be installed as follows:
   1.   At maximum distances of three hundred (300) feet between manholes;
   2.   At all angles in the storm sewer line;
   3.   At street intersections and all points where catch basins, inlets or laterals are to be connected;
   4.   At points where the pipe sizes change;
   5.   At points where the grade of the storm sewer changes.
   B.   All manholes shall be constructed to R.I. Standard 4.32, 4.33 and 4.34, as directed by the Public Works Director. Sanitary Sewer Manholes shall be installed as follows:
   1.   At maximum distances of three hundred (300) feet between manholes;
   2.   At all angles in the storm sewer line;
   3.   At points where the pipe sizes change;
   4.   At points where the grade of the sanitary sewer changes.
   Section 620.3 - Minimum Cover
All subsurface storm drainage pipes within street rights-of-way shall have a minimum cover of three (3) feet. Where three (3) feet of cover is not feasible, reinforced concrete or cast iron pipes shall be used. All drainage structures and facilities shall be inspected and approved by the Public Works Director before covering.
   Section 620.4 - Compaction
Compaction shall be in accordance with R.I. DOT Standard Specifications for Road and Bridge Construction.