The City of Rockdale is an older urban area that had much of its stormwater infrastructure constructed nearly 100 years ago. The early pipe designs conveyed relatively small frequent storms from the low density development of the day.
With increasing development and impervious areas there are less opportunities for infiltration which results in increased runoff and reasonably frequent overland flows.
Council requires onsite stormwater retention as its principal method of reducing flows and flooding throughout the Rockdale area. Retention aims to retain stormwater on the site through the permanent storage of roof or surface water runoff and through the use of absorption pits.
Rainwater tanks are used to reduce these adverse impacts for all developments and for all areas. Absorption pits are used on sites that have typically sandy soils with medium to high permeability rates. Where sites are unsuitable for absorption, or for certain types of development, these adverse impacts are controlled through on-site detention.
As well as conserving the quantity of water, water quality must also be protected. This section also provides direction as to how water can be managed to improve the natural environment by the incorporation of Water Sensitive Urban Design (WSUD) principles.
For details of design criteria and standards, please refer to Council's Technical Specification - Stormwater Management.
Drainage of Low Level Properties
In some instances a property may fall away from the street and the property may not have access to an existing inter-allotment drainage system or it may not be feasible to install an absorption system on the site. In these cases, Council's preferred method for the removal of stormwater from the property is for the developer to negotiate for a private drainage easement to be installed. This typically involves construction of a private drainage system through the neighbouring properties that will join into an existing drainage system. A procedure and checklist to assist with this process is provided at Appendix D of Council's Technical Specification - Stormwater Management
Flood Risk Management
For sites subject to flooding from 100 Year Floods or for flood planning requirements, the applicant is to request a flood advice letter from Council's Technical Services Section - contact 9562 1666. This letter will identify the minimum requirements for the property, as well as any additional works or studies that will be required for the development of the property. For details of design criteria and standards, refer to Technical Specification – Stormwater Management.
For details of design criteria and standards, please refer to Sydney Water's Stormwater Management Technical Specifications.
Council's Stormwater forms and checklists.