Hawkesbury Council Stormwater & Flood Requirements Guide

Developing in the Hawkesbury: Water Comes First

The Hawkesbury local government area combines historic towns with genuine growth pressure. Windsor, South Windsor, Pitt Town, Vineyard, McGraths Hill, Bligh Park, Richmond and North Richmond all see steady residential building activity, and the Vineyard precinct on the LGA’s southern edge is transitioning to urban development under the North West Growth Area program. But no council in Sydney is more defined by water than the Hawkesbury – and no stormwater or flood issue here is minor.

The Planning Controls That Govern Stormwater

The principal control is the Hawkesbury Development Control Plan 2002 (Hawkesbury DCP), which sets out Council’s requirements for drainage, flood-prone land and development standards across the LGA, supported by technical appendices including Council’s civil works specification. Land in the Vineyard growth precinct is guided by separate precinct planning under the Growth Centres framework, with its own drainage and flood controls.

Council also maintains a dedicated flood policy framework and floodplain risk management studies for the Hawkesbury-Nepean valley, which feed directly into how development applications on flood-affected land are assessed.

What Council Typically Requires

• Flood assessment on flood-prone land: for land below the 1% AEP flood level, applications must address whether the site is within a floodway or flood storage area, whether materials are flood-compatible, and whether the structure can withstand flood loading. Minimum floor levels relative to the flood planning level apply – confirm the current levels for your site with Council before design.
• Stormwater drainage plans: a civil engineer’s drainage design showing a lawful point of discharge, pipework, surface levels and overland flow management is expected for dwellings, duplexes and subdivisions.
• On-site detention (OSD): where development increases impervious area, Council generally requires runoff to be detained and discharged at a controlled rate, consistent with the DCP and Council’s engineering requirements.
• Source controls and water quality: the DCP calls for designs consistent with Council’s stormwater management planning, minimising impervious area and incorporating source controls for pollutants.
• On-site disposal in unsewered/rural areas: larger rural-residential lots around Wilberforce and Pitt Town often involve effluent and stormwater disposal wholly within the site, which requires careful soil and grading assessment.

Local Factors: The Hawkesbury River Dominates

The Hawkesbury-Nepean floodplain is one of the most significant flood risks in Australia. The 2021 and 2022 flood events inundated land around Windsor, Pitt Town Bottoms and McGraths Hill and reshaped both community expectations and assessment rigour. Builders should understand three things:

• Flood depth ranges are extreme: the difference between minor and major flooding on this river is measured in many metres, so flood planning levels materially affect floor levels, fill and access design.
• Evacuation matters: Council and the State assess not just whether a building stays dry, but whether occupants can evacuate – road access during floods is a genuine assessment issue in low-lying precincts.
• Local creek flooding: beyond the river itself, local systems such as McKenzies Creek and the South Creek catchment around Vineyard and Windsor create overland flow constraints on otherwise unremarkable lots.

How Builders Should Prepare

Start with a flood information check on the property before you commit to a design – floor levels and flood compatibility requirements can change the economics of a project. Commission a detail survey to AHD, confirm the lawful discharge point, and have your stormwater and flood response documented by a civil engineer in the DA package. On flood-affected land, a clear, well-referenced flood statement lodged up front will save weeks of assessment time.

Contrive Consultants prepares stormwater drainage designs, OSD plans and flood-responsive civil documentation accepted by Hawkesbury City Council. View our services or contact us – call +61 497 848 111 or email info@contriveconsultants.com.au to get your Hawkesbury project moving.