Report by ITV Meridian's Richard Slee
Plans by Southern Water to take more water from the River Test in Hampshire are being challenged by fishermen and conservation groups.
At a hearing today (Wednesday 3 August) the utilities company applied to lift restrictions on the amount of water it can extract.
Southern Water wants to continue to take water when the river flow falls below a level that it had previously agreed would mean water extraction would stop.
Current regulations are designed to protect the salmon population in this delicate eco-system.
Speaking about the regulations, Head River Keeper Peter Farrow said: "You have lower water quality because you have lower water levels which affects the temperature of the water and when you have levels rising to where they should not be you have less dissolved oxygen in the water which is essential for the salmon to survive.
"And if Southern Water want to take more water out of a depleted water source then we will have potential fatalities this year."
Southern Water say the dry winter and hot summer means demand for water is unusually high and so it must extract more water.
But campaigners says that Southern Water has not done enough to conserve water and therefore the company should not be granted a permit to extract more.
Andy Thomas from the Wild Trout Trust said: "It's not as if we have not been predicting this sort of weather for the past 20 years.
"We know climate change is going to happen.
"This are not going to be one in one hundred year events, they are going to be much more regular and we are going to have to get better at storing water in the winter."
Penny Gane, head of practice at Fish Legal
Southern Water issued the following statement: "The Environment Agency changed our abstraction licence on the River Test precisely because of the risk of damage to habitats by taking water in drought.
"Southern Water is engaged in Water for Life - Hampshire, the UK's largest water resources project to reduce reliance on the precious Test and Itchen chalk rivers including the building of a reservoir and water recycling plans.
"The EA recognised reducing reliance on the rivers would not happen over night and that Southern Water's need for drought permits would become more common until new sources of water could be brought into supply.
"To mitigate the potential damage of drought permits, Southern Water agreed with the EA in 2018 to invest £10 million in river protection and enhancement schemes and environmental monitoring, including increased water quality monitoring.
"The River Test fisheries are key partners in delivering that protection and we ensure they are kept informed of progress and we aim to work with them on it."
Critics say the company continues to leak more water every day than it takes from the River Test.
The Environment Agency will announce whether Southern Water can continue to extract water from a lower river level at a later date.