Prohibitions: Throwing, depositing, and dewatering

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The primary purpose of the Navigation Protection Act (NPA) is to balance the public right to navigate with the need to construct works (e.g., bridges and dams). There are three main parts to the Act, the third deals with the prohibition of certain activities to protect the public right of navigation.

Throwing or Depositing

Section 21 of the NPA prohibits anyone from throwing or depositing any “(…) sawdust, edgings, slabs, bark or like rubbish of any description whatever that is liable to interfere with navigation in any water, any part of which is navigable or that flows into any navigable water.”

Section 22 also prohibits anyone from throwing or depositing any “(…) stone, gravel, earth, cinders, ashes or other material or rubbish that is liable to sink to the bottom in any water, any part of which is navigable or flows into any navigable water, where there is not a minimum depth of 36 metres of water at all times (…)”.

These prohibitions apply to all navigable waters, not just those listed on the List of Scheduled Waters.


Section 23 of the NPA states: “No person shall dewater any navigable water.” This prohibition applies in situations where the dewatering prevents public navigation.


Governor in Council must determine that an exemption from these prohibitions is in the public interest, in order for an exemption to be granted.

The mechanism used to do this is called an Order in Council. Many federal and provincial departments and agencies may become involved in this process. Public consultation and environmental assessment are generally required.

Key differences between the NPA and the former Navigable Waters Protection Act (NWPA)

The prohibition against dewatering did not exist under the NWPA.

No significant changes were made to the prohibitions on throwing or depositing.

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