Information and frequently asked questions about seaweed on our beaches
At certain times of the year the amount of seaweed on Thanet’s beaches and bays increases and we are often asked why we don’t take it all away. Seaweed is a natural occurrence on our coastline and the chalk reef where it grows is protected by law. This means that while we can and do remove some of it during the summer months, we are not able to remove as much as some people might like.
We leave seaweed during the winter months (October to March inclusive) to help provide the foraging ground for the internationally important winter visiting birds, namely the Turnstone. This is important so they have enough energy to migrate to the tundra to breed over the summer and is a legal requirement of the Special Protection Area (SPA) for these wintering birds.
It is also a requirement for Blue Flag beaches to leave algal vegetation (seaweed) or natural debris on the beach. Seaweed and other vegetation/natural debris are natural components of both freshwater and marine ecosystems. Blue Flag guidelines state that vegetation should not be allowed to accumulate to the point where it becomes a hazard, however, only if it is absolutely necessary should vegetation be removed.
For these reasons, Thanet District Council arranges for collection of driftweed (seaweed that has become unattached from the chalk reef) during the summer months – from July to September. Driftweed is removed from the main designated bathing beaches, with additional removal from some of the other bays depending on the extent that has come in. Removal generally takes place when the beaches are least busy – normally early in the morning – but this varies as it is dependent upon low tide.
The following gives a brief outline of the council’s seaweed processing and analysis procedure.
The council submits a seaweed deployment application to the Environment Agency and a unique permit number is then issued. Seaweed analysis is then undertaken by appropriate technical experts. Once removed from our beaches the seaweed is further analysed by agricultural specialists prior to being spread on farmland as a fertiliser. Some small quantities of sand can be present on or within the seaweed.
Thanet District Council is provided with analytical reports from the agricultural specialists, as follows:
During 2022, seaweed was applied to the soil at a rate of 30t/ha. The levels of Potentially Toxic Elements (PTEs) applied to agricultural land is very low with all elements providing under 20% of the maximum annual additions, based on the ten year totals.
These levels are much lower than the levels set out in the guidance and legislation and indicate that there is no risk of a build-up of harmful substances in the soil. There are no potentially harmful substances to humans or the environment in the material and measures are put in place to reduce any potential risk.
- All fertiliser recommendations are from the Nutrient Management Guide (RB209), updated January 2019.
- Soil samples were taken and tested in accordance with RB209 by a suitably qualified and trained individual.
- A representative sample of the waste material was taken and sent to NRM Ltd for independent testing.
Frequently asked questions
This takes place between July and September. You can see how this is done in this Twitter thread.Permalink
We remove driftweed (seaweed) from the main designated bathing beaches as a balanced way of managing our coastline, leaving the tidal bays alone. This ensures that the natural balance of the ecosystems are not interfered with unnecessarily.
We do not have the option to remove seaweed at places such as Beresford Gap, Grenham Bay and Epple Bay due to the chalk reef extending up to the proms and slipways. We are not permitted by law to drive vehicles over the chalk reef which is protected as it is a Special Area of Conservation. In addition these are not designated bathing beaches.
We also do not remove seaweed from Kingsgate Bay as it is not a designated bathing beach. At this bay there is no access for the heavy plant machinery required in the collecting and loading of seaweed for removal. Driftweed in this area is left for nature and forms part of the beach habitat.
We remove seaweed only where needed, for example Margate Main Sands hasn’t had seaweed removed for some years as it has not been required.
Designated bathing beaches include – Botany Bay, Stone Bay, Viking Bay, Joss Bay, Fulsam Rock, Margate (The Bay), Minnis Bay, Ramsgate Sands, Western Undercliffe, St. Mildreds Bay, Walpole Bay, West Bay and Westbrook Bay.
More than 900 tonnes has been collected by the council since July 2022. This is more than the last couple of years and it can be cyclical with a number of years in a row not having issues. In the past there have also been years where there has been much more and we have cleared around 2,000 tonnes.Permalink
Our seaweed is taken by prior arrangement with the Environment Agency and granting of permits to a farm in local farms. The current licence allows 1,225 tonnes to be spread at the farm. We don’t move seaweed from Blue Flag bays and put it onto other beaches.Permalink
We have explored different ways to collect the seaweed from the coast over the years and due to the protected sites and the nature of the seaweed we have an established removal method. We use a JCB telehandler – not the surf rake to remove it.Permalink
Seaweed itself does not negatively impact water quality, but contaminants that occur which do impact water quality such as litter and dog faeces may become caught in this. The seaweed harbours these contaminants for longer than if they were exposed just in the seawater.Permalink
The recent heatwave has exacerbated the issue, in hot weather decomposition happens more quickly.Permalink
We leave seaweed on the coast at all beaches and bays from October – March to allow for the natural ecosystem processes in support of local wildlife.Permalink
Clearing seaweed can cost above £50,000 depending on the annual tonnage of removal.Permalink
We allow people to take small quantities of loose driftweed for their own garden or allotment over the summer months (April to September inclusive). Some bays are more suitable for this activity than others. The ones which are more accessible for personal collection include: Walpole Bay, West Bay (west side), Westgate and Minnis Bay, Birchington.Permalink
If you are removing seaweed from our beaches as part of a commercial activity – for example, if you are making a seaweed-based product to sell, or foraging seaweed as part of an organised activity – you will need Thanet District Council approval – and Natural England’s assent – to do so. Please contact: Thanet.Coast@thanet.gov.uk with a description of your proposed sustainable activity.
There is a Seaweed harvesting code of conduct: Thanet Coast’s Seaweed Harvesting Code of ConductPermalink
Natural England is concerned with the protection of the Site of Special Scientific Interest (SSSI) conservation designations which Thanet holds, the Environment Agency is concerned with bathing water quality.Permalink
- Hydrogen sulfide (H2S) is a colourless gas with a characteristic odour of rotten eggs which being denser than air may pool in low areas in still conditions. Hydrogen sulfide occurs naturally in some environments such as sulfur springs, swamps and salt marshes, and is often associated with the decomposition of organic material.
- Hydrogen sulfide has a characteristic rotten egg smell which can be detected at very low levels, well below those that are known to cause health effects.
- Smelling hydrogen sulfide does not mean that it will harm your health.
- Repeated odour events may culminate in real symptoms such as headache, fatigue and nausea. Although these are not direct health effects they are undesirable.
- Real human impacts from hydrogen sulfide are not likely until air levels reach at least 2 ppm for 30 minutes.
- At this point sensitive groups such as some asthmatics may respond with some minor irritations.
- People are normally exposed to hydrogen sulfide in air by breathing it in or by skin/eye contact.
- Any absorbed hydrogen sulfide does not accumulate in the body as it is rapidly metabolised in the liver and excreted in the urine.
- Hydrogen sulfide usually breaks down in air in about 3 days and is dispersed by wind. Therefore exposure is only likely to continue if there is an ongoing source.
You can reduce your exposure by:
- avoiding areas that are known sources of hydrogen sulfide
- keeping windows closed when the odour outdoors is noticeable and opening doors and windows once the outdoor odour has subsided
- not exercising outdoors when the smell is present, particularly if your breathing rate increases.