New figures reveal the River Ver is suffering in the wake of sustained water shortages.
Environment Agency statistics taken from groundwater levels at Ballingdon Farm in Hemel Hempstead show the chalk stream was only at 126mm in May and 125.82 in April.
This is eight meters below the long term average,which sits at 134.1 in May. It has been four years since the average was above what is expected.
These figures have been published in a monthly newsletter from the Ver Valley Society - which is speaking out about the state of St Albans' river.
Water levels have been hit by a range of factors including global warming, a growing population, and manmade course and gradient manipulations.
Chairman of the Ver Valley Society, John Pritchard, said: "It has been going on for a long time, for a number of years, but it is worse now than it has ever been.
"It should be at its best in April or May. This is terrible, it is as low as I have ever seen it.
"The whole river is in a shocking state and flow is desperately low. I have walked the whole length over the last few weeks and basically none of it is looking good."
River Ver is winterbourne to the north of Redbourn, which means that section is supposed to be partly dry in the summer. It is also meant to flow at a stable 10C throughout the year.
John said this natural balance has been unsettled: "It used to be dry one year in seven or ten, but the River Ver has been wet one year in seven or 10."
It also measured 17C last summer and with a covering of ice this winter. Water levels are currently so low that plastic waste from decades ago are coming to the surface.
At a recent litter pick with Plastic Free St Albans, John and his team found a Walkers crisp packet from 1991 and a Peter Dominic lager can from 1988.
The society appeared on BBC1's Countryfile at Easter to talk about these issues.
This comes amid a multi-million pound clean-up project for the River Ver, called Revitalising the RiVer.
It is being managed by St Albans district council (SADC), the Environment Agency (EA), Herts county council's Countryside Management Service and Affinity Water. SADC said the next stage of the project will see it subject to a formal consultation.
A spokesman from EA said it is monitoring the situation: "We are aware that flows on the River Ver have currently been impacted by the warmer and drier weather that we have been experiencing recently."
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