Document 1 · OPW11/0177

1.0    INTRODUCTION

This report is in support of an Operational Works application to Sunshine
Coast Regional Council seeking to develop a residential building at Lots 5 and
6 Serenity Close, Noosa Heads.

In particular, this report addresses water quality and stormwater management
issues raised in the Material Change of Use Decision Notice (Reference
2005/0699) for this project dated 6 December 2010.



2.0    EXISTING CONDITIONS

The subject site currently has bulk earthworks operations (basement
excavation) complete. The entire site consists of loose, poorly graded dunal
sand and as such contains no overland drainage paths since rainwater
infiltrates directly through the permeable surface.




3.0    PROPOSED DEVELOPMENT

Due to the sensitive nature of the local ecosystems, it is proposed to match
existing runoff conditions as closely as possible. In order to achieve this it is
proposed to reintroduce all runoff from impervious areas into the subsurface
via a series of rapid infiltration pits (RIP's). The remainder of the site will be
directed towards the numerous gardens on the site to infiltrate naturally.




4.0    RAPID INFILTRATION PITS (RIP's)

Runoff from impervious areas will be directed to a series of RIP's. Gutters and
spouting will be sized accordingly.       Tate Professional Engineers have
conducted testing for infiltration rates for ground conditions within the
development site. Results were consistent indicating a liner relationship
between driving head and infiltration rate such that:

Infiltration Rate (mm/s) = 4mm/sec + 13.6 x head (m).

Stormwater runoff from roofs is to be conveyed to RIP's via pipework with
runoff from hardstand areas conveyed via vegetated swales.         Rainwater
harvesting tanks are to be employed to capture and store roofwater for use in
irrigation.




S3000/L5&6/11/SWMP- Stormwater Management Plan April 2011                 Page 1 of 2
SH/cf
                         Tate Professional Engineers Pty Ltd