Storm Drainage As-Built plans are required before subdivisions receive final inspection approval and before Water Quality BMPs are approved. 

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

Storm Drainage BMP'S (Water Quality Ponds)
- Actual topography 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

Post Construction Requirements
- High Density Developments subject to the Post-Construction Storm Water Quality Ordinance must meet the requirements on the PCO27 form located at ftp://ftp1.co.mecklenburg.nc.us/WaterQuality/PCO%20Administrative%20manual%20-%20web.doc

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

Jul 2009