Storm Drainage As-Built plans are required before subdivisions receive final inspection approval and before Storm Water BMPs are approved.  The Town of Matthews also requires as-builts before detention basins are approved.

Two copies of plans must be signed and sealed by a Professional Land Surveyor and submitted to LUESA for approval.  Mylars are not required.

Storm Drainage Pipe and Inlet Information
- Slopes
- Pipe length and size
- Pipe material
- Pipe location, if different from plan
- Inlet rim elevations
- Invert elevations
- Verify special requirements (such as Class IV pipe or o-ring joints)

Storm Drainage Ditch Information
- Typical cross-section for all designed ditches.  Indicate location of changes if cross-section varies from the typical.

Storm Drainage BMPs (Water Quality Ponds) &
Detention Basins (in the Town of Matthews)
- Actual topographic elevations of the pond, including what is underwater
- Elevations of all outlet structures
- Size of all discharge features
- Verify existence of drawn-down valves, when required
- Spillway and weir cross-sections

Common Reasons for Disapproval
- No Land Surveyor seal
- Pipe is less than .5% slope
- The velocity at a discharge point is 10 fps or greater (greater than 5 fps on more recent projects)
- Pipe slope differs greatly from design
- There is less than 2 feet + the pipe diameter from the invert to the rim of a drainage structure in the street  (If this happens, be sure Class IV RCP pipe was used).
- The volume of the BMP is undersized
- The BMP aquatic shelf is not within 1 to 1.5 feet below the permanent pool elevation 
- There is no access point or safety bench for equipment to get to the BMP when it needs maintenance
- Outlet devices are not sized according to plans

Feb. 2004