Understanding stormwater

In urbanised areas like Sutherland Shire, stormwater is usually collected by private and public drainage systems and carried to a waterway.

Excessive stormwater runoff can lead to flooding if the drainage system exceeds capacity or becomes blocked. Stormwater flooding is known as minor or nuisance flooding.

Stormwater runoff can also lead to water pollution. Stormwater that runs off hard surfaces like roads and roofs carries pollutants like litter, sediments, oils, fertilisers, detergents and bacteria, which can cause significant environmental and social impacts to waterways.

Responding to stormwater problems

Stormwater problems on Council land (or private property containing Council infrastructure) should be reported to Council. Stormwater issues on NSW Government land, such as highways and railways, should be reported to those agencies.

Basic information on the public stormwater drainage network is available on Shire Maps. More detailed information can be requested from Council.

Stormwater problems on private property are the responsibility of the property owner. Council will investigate only if the natural flow of stormwater runoff has been altered by a property owner to the detriment of another property owner.

This may include situations where stormwater flow from one property to another has been deliberately concentrated, or where there is defective private drainage.

Stormwater problems involving private inter-allotment drainage are the responsibility of the property owners. Find out more about drainage problems from private property.

Stormwater for new development

Stormwater management for new development needs to comply with relevant environmental planning instruments, the 2015 Sutherland Shire Development Control Plan and associated specifications and policies.

Requests to access or modify Council’s stormwater drainage infrastructure as part of any proposed development must be made in accordance with Council’s procedures.

Managing stormwater

Council maintains, renews and upgrades stormwater infrastructure. We also install new infrastructure. These programs are mainly funded by the stormwater levy and include asset cleaning, pipe relining, installation of new drainage and installation of gross pollutant traps.

Council manages an extensive network of stormwater and waterway assets. These assets include built ‘grey’ infrastructure such as stormwater pits and pipes, and ‘green’ infrastructure such as creeks, wetlands and stormwater quality improvement devices.

Grey infrastructure has been installed over many decades to provide cost-effective flood protection for a growing population. New green infrastructure, such as stormwater quality improvement devices, installed in recent decades addresses environmental impacts of urban development and protects Sutherland Shire’s waterways.

  • Stormwater gully pits
  • Stormwater pipes
  • Stormwater culverts
  • Headwalls
  • Constructed open channels
  • Flood detention basins

  • Gross pollutant traps
  • Bioretention systems
  • Artificial wetlands

  • Creeks and riparian corridors
  • Wetlands
  • River estuaries
  • Rehabilitated creeks, wetlands and foreshores

Stormwater and waterway assets in Sutherland Shire represents about a third of the total value of all Council assets. We manage these assets based on performance, condition and serviceability.

For the stormwater drainage network:

  • performance relates to its ability to reduce flooding
  • condition relates to its structural integrity
  • serviceability relates to asset maintenance.

Our ongoing programs assess, maintain and improve asset performance, condition and serviceability. This is described in our Stormwater and Waterway Asset Management Plans:

Hacking River stormwater management plan - PDF - 923 KB
Lower Georges River stormwater management plan - PDF - 17031 KB
Woronora River stormwater management plan   - PDF - 879 KB

Council’s approach to managing our catchments and waterways will be outlined in our Catchments and Waterways Strategy and Implementation Plan, due to be delivered by mid 2025.

The strategy will outline five principles for integrated urban water management:

  • Water cycle: the urban water cycle mimics the natural water cycle.
  • Requirements for water: human and ecological needs are balanced.
  • Local context: accounting for historical, cultural, social, political and economic contexts.
  • Participation: community and stakeholders are involved in planning and decision making.
  • Sustainability: ecological, social and economic needs are balanced for current and future generations.

The strategy will focus on:

  • Stormwater: reduced nuisance flooding and delivering good water quality.
  • Floodplains: community resilience in the face of overland, mainstream and coastal flooding.
  • Coasts and waterways: the open coast, estuaries, creeks and wetlands are attractive, accessible, ecologically healthy and resilient.
  • Catchments: urban catchments are managed to ensure they are liveable and sustainable.

The strategy is informed by several management challenges, opportunities and emerging trends.

  • Data: Good data underpins effective urban water management. Data on assets, environmental processes and the community continues to be collected, often using innovative methods.
  • Urban redevelopment: Population growth and pursuit of higher living standards drive urban redevelopment. This can put pressure on the environment. Urban redevelopment presents both a challenge and opportunity for addressing urban water problems.
  • Community awareness and expectation: The community has good awareness of, and high expectations for, addressing urban water problems. The community’s acceptance of risk associated with these problems is declining.
  • Constraints to new infrastructure: Built green infrastructure like stormwater quality improvement devices is a new type of asset that will ‘overlay’ existing grey infrastructure. There are technical and financial challenges associated with this.
  • Community and institutional capacity: The ability of community, governments, industry and other stakeholders to pursue integrated urban water management has improved but requires ongoing effort.
  • Climatic variability: Short and long-term climatic changes, such as predicted sea level rise and changes to rainfall intensity, need to be accounted for.

The strategy will have an implementation plan outlining actions for each area of focus and is due to be delivered by mid 2025.