Information about the condition of the Lakes

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

Condition update - 30th September 2019

The River Ver had completely dried up but is now flowing again as a result of the heavy rain we have had over the past couple of weeks.  The affect of the rain will be short lived as water currently flowing in the river is run off from the surrounding land. We expect the river to dry up again over the coming weeks.

Low water level small lake
The warm and dry weather conditions are also promoting the growth of aquatic freshwater weed that is floating on the surface. This gives a green carpet effect and algae growing in the water can give it a green/brown murky look.  The Park Rangers are removing as much of this weed as they can.

As water levels drop it will continue to expose silt on the concrete bed.   Fencing and signs have been installed at these locations warning the public to keep off the silt.

We have prepared a list of frequently asked questions, please see below.  If you have a questions that has not been addressed below please contact a member of the team at

If you would like more information about the current river and groundwater conditions please visit the Environment Agency website - Monthly water situation report - Hertfordshire and North London

Revitalising the River Ver Project

The Council is currently working in partnership with the Environment Agency on an overall project that will see improvements made to the River Ver, through St Albans including the lake at Verulamium Park. A feasibility Study has been produced and detailed designs are currently being prepared.

For more information about the project please visit the website:


We have prepared a list of more frequently asked questions below.  If you have any questions that are not addressed below please contact a member of the team at

How can I help?

The amount of water we use at home and at work has a real impact on the River Ver and lakes in Verulamium Park.  

The Lakes are fed by the River Ver and the river is fed by springs along its course with water coming up from the aquifer.  In this area, the water that is supplied to our homes and business is pumped out of the the aquifer. The aquifers are filled by rain water seeping down though the soil.

A combination long term, below average rainfall and the pumping of water out of the aquifer means that groundwater levels are very low and the River Ver, like many other chalkstreams in this areas is drying up.

These water saving ideas can really make a difference:

  • Take a short, 4 minute shower instead of a bath
  • Turn off the tap while brushing teeth
  • Install a ‘Save-a-Flush’ device if you have a single flush toilet
  • Only run your washing machine or dishwasher with a full load
  • Fix dripping taps – if you need an approved plumber visit
  • When boiling the kettle, only boil enough for your immediate use
  • Use a water butt to collect rainwater, which can be used to water your garden or wash your car
Affinity Water customers can order water saving products free, such as water efficient shower heads, tap aerators and fun products to encourage water efficiency for children.

For more information visit:

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How does the lake fill with water?

Water feeds into the lakes from the River Ver through a sluice system. This mean that the amount of water in the lake is dependent on water levels and flow rates in the river. Water levels in the river are effected by factors such as; abstraction of groundwater for public water supply from the chalk aquifer and long term low rainfall.

If you would like more information about the current river and groundwater conditions please visit the Environment Agency website - Monthly water situation report - Hertfordshire and North London

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Why is the water in the lake in poor condition?

The volume of water in the lakes is large in comparison to the amount of flow they receive from the River.
Very low inflow of water from the river means it takes a long time for water to be flushed through the lake and this exacerbates the water quality issues.
The lakes are large, but very shallow,  with an even depth of approximately 1m. The high surface area to volume ratio makes them more susceptible to progressive warming throughout the summer with dramatic water temperature changes and evaporation.
This creates ideal conditions which contribute to algal blooms and excessive weed growth and results in the oxygen levels crashing.  Organisms such as bacteria, archaea, algae, protozoa which are vital to the health of the water cannot survive in these conditions.

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

Yes, however we would advise you not to allow your dog to go into the lake as there is a risk of it getting stuck in the exposed silt.  Dogs should be kept on a lead at all times while walking around the lake to reduce stress on the waterfowl.

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What is green stuff floating of the lake surface?

This is a type of aquatic weed similar to seaweed but in fresh water. It floats on the surface and is blown by the wind and normally collects in the northeast and southeast ends of the lake. The Park Rangers remove as much as they can. However the weed grows back very quickly.

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When will improvement be made?

The work needed is significant and complicated.  The Environment Agency are currently working on detailed designs and once these have been completed we will need relevant consents and planning permissions.  Subject to funding, it is hoped that we may be able to start work some time during 2020/21

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

We have very little control over the water that come into the lake.  The lake is fed by the River Ver and if the river is in flood we can close the sluice gates but when the river is low such as now we open the gates fully. Even fully open there is not enough water in the River to keep the lakes full at the moment.

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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 important that a long-term, sustainable solution is implemented to safeguard the lakes for the future.  

A feasibility study has been completed in partnership with the Environment Agency they are currently producing detailed designs.

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Why don't you just dredge the lakes?

Simply removing the silt that has built over the past 50 years will not solve the issue and the cost disposing of the estimated 9000 tons would be too much.

We propose instead to repurpose the silt and use is to plant water loving plants around the fringes of the lake that will help to clean the water and keep it oxygenated.

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Why should I not feed the duck and other waterfowl?

We have produced a fact sheet which explains why you should not feed the waterfowl.

Keep Our Wildfowl Wild, Fact sheet

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Date of last review: 25 October 2019