16-02-23 Noosa Council Ltr

FORM B — UNDER-DRAINAGE

Purpose: To ensure under-drainage is installed correctly before the bioretention media is installed.

ITEMS

Base of system free from debris
Liner (typically filter cloth) correctly
installed

There is no fabric ‘sock’ around the under-

drainage

Correct under-drainage has been

supplied and slotted at 2 mm or smaller

Under-drainage pipes are laid at the
correct spacing (small bioretention
system 1.5 m, large system 2 m)

Required grade (verified using level or
string line)

Under-drainage pipes laid at required

grade (verified using level or string line to
achieve design level 25 mm and 0.5%
grade)

CHECKED

SATISFACTORY

 

Alljunctions and connections have been
appropriately sealed

Top of clean out points at design level (i.e.
approximately 50-150 mm above filter
media surface )

 

 

 

ACTION (IF
UNSATISFACTORY)

 

HOLD POINT: Superintendent and bioretention designer inspection and sign-off before proceeding.

Comments (attach and refer to additional pages if necessary)

NB; As constructed survey and drawings and photos attached

Signed by superintendent:
Print name:

Date:

Signed by bioretention designer:

Print name:

Date:

INITIAL