SUPERSEDED - Compiled Reference Document - RAL25 0011 (As Published)

LINDSAY CONSULTING PTY LTD
STRUCTURAL AND CIVIL ENGINEERS
ACN 079 744 808 ABN 61 478 386 385 GST REGISTERED

AS TRUSTEE FOR THE LINDSAY FAMILY TRUST




2.5 Flooding

The proposed development site is not impacted by flooding.


3.0 - STORMWATER QUANTITY MANAGEMENT

The stormwater quantity analysis of the existing and developed site conditions has been carried out for
the project, refer appendix C with QUDM requiring the fraction impervious for the site to be low, 0.4, for
the existing site with the fraction impervious increasing to 0.9 for the proposed subdivision.

Lindsay Consulting Pty Ltd have calculated that the 100 AER non-worsening volume for the site 10000
lt with the proposed tank to be provided to be constructed at the front corner of the proposed allotment,
connected into the existing system in Crank Street.

A check of the proposed lot shows that 400 SQM of roof area alone will fill the detention tank during the
100 AER event. The tank is shown on the attached drawings.

Further to this the development will comply with the maximum discharge flow rate of 25L/s for a single
kerb outlet for each of the proposed lots.



4.0 - WATER QUALITY MANAGEMENT

4.1 Operational Phase

The proposed development is not required to meet the Queensland Governments State Planning Policy
(July 2017) as the development site area does not exceed the 2,500m2 minimum.


4.2 Construction Phase

Management of stormwater runoff during construction and the implementation of an erosion & sediment
control program is necessary to avoid impacts to receiving waters from pollutants typically generated
during the construction phase. Typical pollutants are described in 1 below:
Table 1 – Pollutants Typically Generated During the Construction Phase

              Pollutant                                                       Sources

 Litter (Gross Pollutants)                    Paper, construction packaging, food packaging, cement bags.

 Sediment                                     Unprotected exposed soils and stockpiles during earthworks and building.

 Hydrocarbons                                 Fuel and oil spills, leaks from construction equipment.

 Toxic materials                              Cement slurry, asphalt prime, solvents, cleaning agents, wash waters.

 pH altering substances                       Acid sulphate soils, cement slurry and wash waters.



Off. 2C/82 Parker St, Maroochydore 4558
OFFICE: (07) 54 792 118 MOBILE: 0412 313 645 FAX: (07) 54 510 118
E-MAIL: [email protected]                                                                      2