Appendix A- Stormwater Management Plan

                                                                                    Callaghan & Toth

1.     INTRODUCTION

The site subject to this report is at No.18 Pearsons Road, Cooroy. The existing lot contains
one house, two driveways (only one concreted), a pool, and a shed. The back half of the lot
is undeveloped and is vegetated by grasses and shrubs. A new lot will be created in this
rear area, with access via a 4.5m wide easement for access and services along the northern
boundary.

The stormwater management assessment undertaken in this project considers:
    • The extension of the existing interlot drainage system to collect flows from the new
        driveway, the new house and yard runoff,
    • the increase in impervious area of the lot due to the proposed additional building and
        measures which can be incorporated into the design to attenuate the resultant
        increase in runoff back to predevelopment levels.

The existing dwelling catchment drains to Pearsons Road. The rear yard and new driveway
drain to an existing interlot drainage system in lot 17.

The new dwelling site and battle axe driveway drain to the north east corner as shown on
plan 2102-01A the proposed new drainage system will replicate the existing catchment split.


1.1    Response to Conditions of Approval

TABLE 1.1: Response to Information Request
 NUMBER CONDITION                                                             RESPONSE
 2a          Demonstrate that there will be no offsite impacts and that       Details shown on Plan
             the runoff from the site is suitably controlled to ensure that   2102-01A and Section
             the downstream environment is not adversely affected or          4.2
             destabilised
 2b          Details of collection and discharge of stormwater runoff         Details shown on Plan
             from the buildings and the handstand areas                       2102-01A
 2c          Details of how the proposed Lot 20 will not increase             Details shown on Plan
             stormwater runoff (volume and velocity) into proposed Lot        2102-01A and Section
             21, specifically with the increase in hardstand area (i.e.       4.2
             driveway)
 2d          Any required stormwater easement in proposed Lot 21 for          Details shown on Plan
             the benefit of proposed Lot 20                                   2102-01A
 2e          The structures for the operational phase of the                  Details shown on Plan
             development, including size of the pipes required, levels,       2102-01A
             grades, discharge points, etc
 2f          Be consistent with any site-specific geotechnical report         This SWMP is
             recommendations                                                  consistent with the
                                                                              Encompassing
                                                                              Subdivision SWMP
                                                                              which was based on a
                                                                              geotechnical report


2.     DESCRIPTION




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