Water Affecting Activities-dams

Posted 15 July 2019.

If you are considering building a new dam, deepening or enlarging an existing dam or cleaning out an on‐stream dam, a Water Affecting Activities (WAA) Permit may be required.

SA Arid Land NRM’s Senior Water Resource Officer, Aaron Smith, said that due to the dry conditions there had been an increase in dam construction enquiries.

“It is important that landholders understand the permitting requirements for construction or modification of dams,” he said.

“Dams require a permit as they have potential to impact downstream users and the environment through reduced flows or changes to timing of flows. They can also effect erosion, sedimentation and impact water quality.” he said.

Not all dams require a WAA permit including dams under 10 ML. However a permit is required when enlarging an existing dam beyond 10 ML.

Permit assessments are site specific. Mr Smith says it is often best to avoid in-stream structures built across a watercourse or drainage lines that will effectively capture all flow until the structure is full.

In these situations a low-flow bypass may be required. A low-flow bypass is a structure such as a small weir that allows flow around the dam to ensure the downstream environment continues to receive water.

“If someone is looking to install or modify a dam it is best to give me a call to discuss the proposed works, the volume and location to determine if a permit is required,” he said.

When planning the works, Mr Smith says to consider that permits can take up to eight weeks if external approvals are required.

Senior Water Resource Officer Aaron Smith can be contacted on 0417 643 956 or via email at aaron.smith3@sa.gov.au

For more information, take a look at the WAA fact sheets here