"It's an incredibly scenic, beautiful spot [but lifeguards] are not being seriously considered, so there's no fundamental change to the site."
He said using lifeguards would send the message that people were encouraged to swim there, when council recommends people avoid doing so.
Several combining factors make the falls hazardous to swimmers.
Bowater said the extreme variations in depth meant swimmers could go from waist-deep water around the edge to depths of up to 19m in one step.
"We've got very deep water there, that's one of the main hazards.
"There's a sharp drop-off from the edges. There are some shallow edges that are quite visible and there are even rocks where you can cross from one side to the other but they are slippery.
"You've got a sharp drop down to that deepest point."
The waterfall is 30m high, and as fresh water hits the pool from that height it aerates, making it less buoyant.
The temperature of the water can be as low as 7C, at which point Bowater said the "gasp effect" can come into play.
"The gasp response is an inability to breathe properly in cold water, and that can catch people unaware if they're jumping in."
The council has made efforts to discourage people climbing to the top of the falls to jump off, closing tracks up to the highest point.
Murky water could also hide hazards lurking underneath.
"Water levels can change dramatically during or after heavy rainfall. It can flood quickly," Bowater said.
"Alongside that flooding, objects could get washed over the top of the falls such as logs."
Bowater said the council's focus was to ensure people were sufficiently informed of the risks of swimming at the falls and that appropriate measures were taken.
"We're reviewing signage again. We are also obviously going to be working with the police and anything that comes out of any coronial inquiry recommendations.
He said the council had put in a number of mitigation measures, including warning signage and rescue life rings.
"We can't stop people going there, so it is about being aware of the hazards and following some basic water safety code, which really is: know your limits, swim with others, be aware of the potential dangers, wear suitable clothing that won't add weight and drag you down, and if you're not a strong swimmer you should question why you're in there at all."
Water Safety New Zealand acting chief executive Mark Lindsay echoed the importance of taking care.
"Any body of water poses a risk, regardless of whether it's a lake, river or picturesque waterfall. The onus is on people to think about water safety."
About 12,000 people visit the spot each year.
