Two Dubbo teenagers have died at the weir in the past four years.

The council has asked Public Works NSW to study its proposal to place large objects at the downstream face of the weir, aimed at de-energising the water flowing over it.

Department staff are expected to have answers to technical, regulatory and financial questions by the end of February or early March.

The council’s acting technical services director Ian Bailey yesterday talked of it looking to create a “cascade” of water to replace a sheer drop.

Water swirls as it falls over the “wall across the river” that sits on the riverbank.

Its energy can prove deadly as indicated by new signage at the structure warning “weirs kill”.

Rocks and concrete blocks are being considered as a means of blunting the water’s force.

“The energy of water dissipates as it swirls around rocks,” Mr Bailey said. The council changed the message on signs at the weir after the October 2011 death of 19-year-old James Kennedy, now being investigated by the NSW Coroner.

An inquest into the drowning of 15-year-old Joshua MacFarlane in 2008 led the council to erect signs and barriers at the weir.

Mr Bailey said Public Works NSW had a wide brief that allowed it to examine the “possibilities” of the cascade concept.

He said the council was “aiming to do what it can to make the area safer”. But the acting director urged the community not to lose sight of a stark reality.

“Any river is a dangerous place,” Mr Bailey said.

Wikipedia describes a weir as a small overflow dam used to alter the flow characteristics of a river or stream.

In most cases weirs take the form of a barrier across a river that causes water to pool behind the structure , but allows water to flow over the top.

Weirs are commonly used to alter the flow regime of the river, prevent flooding, measure discharge and to help render a river navigable.