Stormwater connections to natural waterways policy

Policy document number: DD_069849 Version: 3 Last updated: 18 June 2026

1. Overview

1.1 At a glance

On occasion we allow stormwater connections into our open channel natural waterways that we own/manage. These connections must ensure:

• stable transition from a constructed drainage system to the natural waterway
• sustainable water management
• restoration of native vegetation following construction.

1.2 Scope

Our policy applies to you when you're proposing to construct a stormwater connection to a waterway that is owned and managed by us. It applies to all connection proposals for residential, commercial or industrial developments.

1.3 Objective

Our policy helps us to ensure you design and construct proposed stormwater connections to a safe and sustainable standard by:

• minimise the number of uncontrolled stormwater discharge
• ensuring they cause minimal environmental impact to the waterway and its water quality restoring and maintaining disturbed waterfront and riparian vegetation through appropriate rehabilitation.

2. Policy in detail

Connecting stormwater to natural waterways affects the waterway and riparian corridor. We'll provide information, advice and responses to enquiries or applications to enable urban development. We'll consider connections to natural waterways to discharge stormwater if the below requirements are met.

2.1 Determining a Stormwater connection

We want to minimise the number of uncontrolled stormwater discharges into natural waterways. If an existing stormwater line is available, new lines must connect to it. If this is not viable, the owner or developer must liaise with local council and us to identify an agreed connection point and design specifications.

2.2 Type of development and its water quality

New stormwater connections must limit environmental impact to the waterway and its water quality. Water quality provisions vary depending on the type of development the connection is intended to support. Stormwater run-off from residential developments differs from commercial/industrial developments, so there are specific provisions to correctly manage the water quality being discharged into the natural waterway.

The Stormwater connections to natural waterways guide explains these provisions and other requirements under ‘Outlet structures. Outlet structures are the discharge points at the end of the stormwater connections. Outlet structures must provide a stable transition from the constructed drainage system to the natural waterway. The structure must also be appropriate for the surrounding environment. To minimise the chance of erosion due to discharge flow, outlet structures must be:

• built offset from the waterfront and discharge in an angled downstream direction
• structurally stable (using appropriate geotextiles and a combination of rock sizes)
• accessible
• safe for the public.

2.3 Vegetation

You must re-establish any disturbed waterfront vegetation after connecting to a natural waterway. This is necessary to restore native vegetation cover to disturbed areas within the riparian corridor. For detailed requirements, refer to the Stormwater connections to natural waterways guide.

3. Definitions