In the Arnhem Land community of Ngukurr, elder Clarry Rogers is worried plans to allocate water to new gas fracking and cotton industries could damage his important dreaming and bush tucker sites along the Roper River.
"I'm pretty concerned about it, that's why we want to [have] our voice heard, I know cotton takes a lot of water," he said.
"The level of the water [we believe] could drop and then we'll be suffering because we won't be getting any flows from the Roper."
Other Indigenous communities along the river's 300 kilometres, in its 81,000 square kilometre catchment, are also concerned.
A group has banded together to raise attention to the issue, commissioning Melbourne artist Simon Normand to paint a 13-metre map petition of the river.
Ngukurr elder, Robin Rogers, said he said he felt the images were more powerful than words.
"That maps tells everything, it's just like a bible," he said.
"It's the map of the dreamings, like kangaroo, mermaid and goanna.
"So white men can understand what we're talking about."
Eight language groups represented
Mr Normand travelled through communities including Ngukurr, Jilkminggan and Minyerri, to ask traditional owners what dreamings they would like added to the map.
"The main thing we're trying to show is that it's a united voice," he said.
"It's really about the communities having the opportunity to voice their belief system in a way that shows the connection to country in such a huge region.
"There's eight different language groups all represented on the one river, and I think that's why it's so powerful."
Community leaders have also added their petition messages to the map.
"It says 'all the songlines follow the water, if you take our water you kill our culture, you can take your plans for cotton, for dams, for mining, away with you'," Mr Rogers said.
The Northern Territory government is soon to release its plan to allow flood plain harvesting for the first time, for new crops including cotton.
NT Farmers chief executive, Paul Burke, said he had been briefed on the draft plan and was confident it would be sustainable.
"We're predominantly talking about on farm dams, and filling in those flood events that we know that we always get in the Northern Territory, so utilising a small percentage of that water when it's most prominent," he said.
"What I would say is, there needs to be more water planning done, and there certainly needs to be more consultation done with traditional owners to allay those fears."
NT government to start charging for water
The NT government said its Top End water rules require 80 per cent of river and aquifer flows to be kept for the environment.
Water Minister Lauren Moss said big gas and agriculture developments would for the first time start paying for water.
"The Northern Territory government has a very robust framework around how we allocate and manage water," she said.
"For the first time the NT will have a long term strategic plan around how we use water and how we protect water, and there will be further consultation with the community on that plan."
Charging gas companies for water was one of the recommendations of the government's fracking inquiry, which it has promised to implement.
It has not yet said how many gas, mining and big agriculture projects would be charged for water, or when that would start.
Clarry Rogers said the group would present the Roper River map to federal ministers in Canberra.
"When it's all finished and it's ready to be presented to the federal government, I'm willing to go to Canberra with Simon and other traditional owners from the area that we're supposed to be looking after," he said.
"We will be talking to the politicians and explaining that it will affect us if the water is taken from the Roper, that we will suffer."
