Information about the condition of the Lakes

Printer-friendly page

This page has been set up to provide updates and to answer some most commonly asked questions about the lake.

13th April 2017

Silt is to be removed from Verulamium Park lakes and will start on Tuesday 18th April 2017.

The Council has drawn up plans for the complex and challenging operation with its waste contractor Veolia.
Similar to last year a tanker will be used to suck the silt from the lake, this time from the area near the bridge between the two lakes through a pipeline before taken it to a treatment plant near Redbourn for disposal.

The work is expected to be completed by Friday 28th of April 2017.

Update 12th April 2017

You may be aware that there has been a spate of water fowl deaths recently. We would expect to find bodies from time to time (birds are migatory and fly in and out of the park all the time) but we are working with The Department for Environment, Food and Rural Affairs to keep an eye on the matter.

We are also working with the Environment Agency on a long term plan which will see improvements made to the River Ver and Lake.

If you do find an unwell or dead bird/animal please do not attempt to move it from where you found it. Please report it to our team on 01727 819366.

Update 5th August

Up to 150 tonnes of silt are to be removed from Verulamium Park lakes in St Albans in a major effort to improve the water quality.

St Albans City and District Council has drawn up plans for the complex and challenging operation with its waste contractor Veolia.

The scheme will cost £29,000 and is seen as a breakthrough in short-term attempts to improve the aquatic environment around the ornamental lakes.

A tanker will be positioned near the pumping station opposite Westminster Lodge, the closest hardstanding to the lakes. A half-mile long pipe will be laid out from there to the lakes.

Silt will then be removed by suction and stored in the tanker before being taken to a treatment plant near Redbourn for disposal.

Work on the project is expected to start next week with the aim of it being completed by mid-August.

Removing the silt is the latest part of this approach to improving the lakes’ environmental condition.

The silt spoils the appearance of the lakes and is believed to be contributing to a foul odour, reducing the enjoyment of walkers, joggers, birdwatchers and other park users.

It has mainly gathered at the edge of the larger lake near the Fighting Cocks pub and at the bridge which separates the two lakes.

A new, dedicated park ranger has been appointed to work full-time on the lakes.

He will engage residents and educate them about the harmful consequences of feeding the birds.

Update: 4 July 2016

We have seen a reduction in the amount of floating algae on the surface.  This is most likely due to the recent cooler weather conditions and  increased flow of water from the river following recent heavy rain. However, the increased flow from the river will bring a spike in nutrient levels which in turn could result in an algae bloom.  There is some evidence of this in the small lake as the water has in the last few days turned a milky green colour. The water in the large lake however remains clear.


As you know we attempted to remove some silt from the lake in the corner near the causeway using a JCB. Unfortunately, this was not overly successful and has not made a big impact. 

The actual removal of the silt from the lake was not a problem, the issue was that we simply could not remove enough material to make a difference using this method.

To this end we have now met on site with Veolia with a view to removing approximately 60 tons of sediment.  This will happen in the area near the causeway toilets and at the opposite end by the bridge between the two lakes. The representative from Veolia proposes to use a large tanker with a suction system, to suck the sediment from the lake and take it to be processed at a treatment plant near Redbourn.

Update: 31 May 2016

Decaying algae has collected in the corner at the Fighting Cocks end of the lake and the silt has now broken the water surface.
We have brought a skip into the park and tomorrow (Wednesday June 1st)  will be attempting to use a 3 metre reach small digger to extract the silt from this corner of the lake and from in front of the exit grid. We will attempt to dig the silt out and hope it holds together enough to extract and place in the skip. The skip will remain until the water has drained away which will allow the skips removal, to a licenced waste site.



Background and history

Verulamium Park contains two lakes, one small boating lake and one large lake containing two islands. Construction started on both lakes in September 1930 and was completed in February 1932. The lakes are constructed of a concrete edging and bases, no more than 1m deep. The larger of the lakes contains two wooded islands, one of which supports a heronry.  The lakes are surrounded by amenity grass and/or surfaced footpath. The marginal or semi-aquatic vegetation is limited to the northern end of the large lake.

The lakes support a large population of waterfowl, maintained and increased through the popularity of feeding by visitors.  This has resulted in a great input of nutrient-rich bird droppings leading to a highly eutrophic, (oversupply of nutrients, which induces explosive growth of plants and algae which, when such organisms die, consume the oxygen in the body of water), heavily silted water body.

The lakes are fed by the River Ver through a sluice system. This sluice has a restriction plate fitted and does not allow water to pass through during low river levels.  In addition the extraction of water from the River Ver is licensed by the Environment Agency.

Low water levels in the river mean that the lake does not receive any fresh water from the river for months on end during the summer.

Low or no water movement in the lakes particularly in warm conditions can result in the water becoming stagnant.

The northern and south eastern corners of the large lake are particularly susceptible to accumulating flotsam. This is because prevailing winds tend to push debris into that part of the lake.  Every other day (on average), the Park staff monitor the lakes and clear any debris.

With the lakes being only 1metre deep and formed of concrete, they quickly warm up. This provides limited habitat for the plant life that is needed to oxygenate the water and help remove nutrients. The lakes therefore suffer from low oxygen levels and high levels of nutrients. This can cause algae blooms and poor conditions for fish.

In 2008 the boating lake was drained and the silt removed at a cost of £20,000. The silt had to be taken to a contaminated waste site due to the heavy metals in the silt. After seven years the boating lake has the same amount of silt deposited in it as before removal in 2008.

Frequently asked questions

How does the lake fill with water?

The lakes are fed by the River Ver through a sluice system. The extraction of water from the River Ver is licensed by the Environment Agency.

Back to the top

How much will the improvements work cost and who will pay for it?

The cost will be significant and will need to be met by the Council but this could form part of an overall funding bid.

Back to the top

Is it safe for me to walk my dog around the lakes?

Yes.  To prevent dogs contracting botulism it is essential that they do not touch dead animals. Dogs should be kept on a lead at all times while walking around the lake so to reduce stress on the waterfowl.

Back to the top

What is currently floating of the lake surface?

It is a type of algae that has risen from the lake bed and the wind has drifted it to the area in front of the bridge.

Back to the top

What where the issues last year?

Last year there was an outbreak of Avian Botulism.
Avian botulism outbreaks in wild water birds occur relatively frequently in England and Wales. Large numbers of birds may be affected and outbreaks or incidents can last for several weeks and may reoccur. Affected birds may be paralysed and die.
Outbreaks are not uncommon in bodies of water such as the lake, particularly during the summer months. The lake is shallow (only 1m on average) and the bird droppings create too many nutreints,  allowing algae blooms.  This causes oxygen levels to drop. 

Back to the top

When will improvement be made?

It is anticipated that work will be carried out during the course of the next 2 or 3 years.

Back to the top

Why don’t you allow more water from the river into the lake?

The sluice gate is open to its maximum. Low water levels in the river during a hot summer can mean that the lake does not receive any fresh water from the river for a long period.

Back to the top

Why is it taking so long to find a solution?

The issues are complicated and there no one simple way to resolve them.
It is also important that a long-term, sustainable solution is implemented to safeguard the lakes for the future.

Back to the top

Why should I not feed the duck and other waterfowl?

We have produced a factsheet which exlains why yo should not feed the waterfowl.

Keep Our Wildfowl Wild, Fact Sheet

Back to the top

Will the lake be dredged and silt removed?

No. This would be a very costly and short term option. We are currently working with the Environment Agency and Affinity Water to draw up a project brief to go out to tender The brief will ask companies to produce and price schemes that will improve the quality of the River Ver chalk stream  and provide a sustainable solution for Verulamium Lake.

Back to the top
Date of last review: 18 April 2017