There are growing concerns about the impact draining a reservoir is having on wildlife.

Over the last week or so, there have been reports of bird nests on the banks of Aldenham Reservoir being destroyed by predators.

There are also concerns about blue and green algae which has turned the reservoir water "toxic" - prompting Hertsmere Borough Council to issue warning notices.

It is all thought to be caused by the continued drainage of the reservoir by its private owners.

A sluice has been open for more than a year which has seen the water level drop significantly and "hazardous" sand and slurry form around the edge of what's left of the water.

The reservoir owners, Liberty Lake Leisure Ltd, say the drainage of the reservoir, which they bought in 2015,  is necessary to ease pressure on a dam wall.

Borehamwood Times:

But locals are growing increasingly concerned about the impact this is having on the environment.

Related: Hiker 'sinks to his waist in mud' at Aldenham Reservoir

In recent days, a Borehamwood-based animal rescue organisation, Moonstone Rescue, says it had been called again to the reservoir because bird life had become "exposed to predators".

The organisation said it has received reports of cygnets being killed or attacked because the nesting areas have been left "totally exposed".

One of Moonstone's volunteers, Matt, visited this week and said he counted at least ten nests which had been destroyed by an animal - nests that would normally have been given good protection by water.

Borehamwood Times: An exposed nest at Aldenham ReservoirAn exposed nest at Aldenham Reservoir

Moonstone says the issue "needs to be addressed urgently" by the landowners and the organisation is calling on residents to put pressure on the authorities.

At a Hertsmere borough council meeting this week, Borehamwood Labour councillor Dan Ozarow, who is also part of the Save Aldenham Reservoir campaign group, shared a story with members about a swan at the reservoir.

He said: "Residents across Hertsmere were appalled this week at the heartbreaking sight of a mother swan desperately trying to shield her eggs in their nest at Aldenham Reservoir. She originally laid them on the bank of the water.....the swans have been spotted but there are no eggs left in the nest and there are no cygnets in sight."

He said a nine-year-old boy called Harry from Elstree had been compelled to write to the Queen asking for her help protecting the swans.

Watch the exchange between Cllr Ozarow and the council leader Cllr Bright below

Related: Protest takes place at Aldenham Reservoir

Cllr Ozarow added: "In recent weeks water levels at Aldenham Reservoir have reached dangerously low levels as the sluice has remained open. An independent report commissioned by the Save Aldenham Reservoir campaign highlighted how this causes a catastrophic impact on marine life, surrounding wildlife and the local ecosystem."

He asked the leader of the council: "Whilst the reservoir is privately owned by Liberty, the council is responsible for environmental health, so what is Hertsmere Borough Council doing to ensure that the sluice is closed and Hertsmere's jewel is protected?"

Council leader Morris Bright acknowledged that the situation at the reservoir is "very sad" adding "we have to everything we can do protect it".

Borehamwood Times: Aldenham ReservoirAldenham Reservoir

But Cllr Bright stressed it is the Environment Agency that controls reservoirs and its owners, saying: "The Environment Agency needs to have pressure put on it and that's from campaign groups, as well as the rest of us."

Related: Aldenham Sailing Club departs Aldenham Reservoir after more than 80 years

The co-owner of Aldenham Reservoir, Mahesh Gosrani, of Liberty, told the Times on Friday that people "cannot imagine the pain he and his family feel" when they hear concerns for the wildlife.

Mr Gosrani added: "Our Jain faith has a very simple philosophy, which encompasses, loves and respects all forms of life not just human beings but animals, trees, plants and insects. We believe that 'all life is interdependent' and should therefore be respected."

The Gosrani's commissioned an inspection of the dam wall in 2019 which concluded there were "concerns" over the movement of it - but "no immediate action was required".

Borehamwood Times: The reservoir pictured in 2020 after drainageThe reservoir pictured in 2020 after drainage

Related: Private owners say they will not sell reservoir as community concern grows

Repairing the dam, which is more than 225 years old, could cost millions and planning applications for homes on nearby green belt land and for pods around the reservoir to help pay for those costs have proved unsuccessful.

Mr Gosrani said the dam wall was inspected again on July 19 and a report is expected soon.

He said: "We had a great vision for our reservoir but we cannot make the decisions that convert dreams into realities."

Although Mr Gosrani acknowledged the impact the drainage is having on the reservoir, he told a Hertfordshire County Council officer on July 22 that he believes the dam inspection report will be a "wake-up call for the authorities".

There was no indication that the water levels would be allowed to rise again in the near future.