Approved Plans and Documents - OPW22/0303

FORM B — UNDER-DRAINAGE

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

ITEMS CHECKED

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)

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:

Document Set ID: 22315062)! 1 dé
Version: 1, Version Date: 20/02/2023

Signed by bioretention designer:

Print name:

Date:

 

INITIAL