Seagrass and Recreational Yachting

The Solent is now centre-stage in an important new initiative, led by Natural England, to find ways to protect critically endangered Seagrass Meadows. The Life Recreation ReMEDIES project (Reducing and Mitigating Erosion and Disturbance Impacts (E) affecting the Seabed) will particularly focus on the threats raised by the mooring and anchoring of recreational boats. Five sites have been chosen along the south coast for the study, the largest and busiest being the Special Area of Conservation, Solent Maritime. It includes areas of Chichester Harbour, Langstone Harbour, the stretch of Coast between Stansore Point and Hurst Castle, and that between Osborne Bay and Yarmouth on the Isle of Wight.

Boat owners are learning what ecologists have known for years, that seagrass meadows are highly important; they stabilise the seabed, absorb carbon, slow climate change and are the natural habitats for a plethora of marine animals, algae, rare seaweeds and are nurseries for many of our commercially valuable fish. They buffer wave energy, reducing erosion of our coastline, always a concern in the Solent. The evidence shows that traditional buoyed mooring chains scour deep abrasions in the sediment, thereby destroying the habitat. Recovery is slow and difficult as the scar will often fill with debris rather than allow the sediment to settle to its previous depth, thus enabling the rhizomes and root systems to re-establish. Evidence of long-term damage to the seabed from anchoring is less apparent but the random nature of the fall of the anchor and chain, whilst not scouring the sea-bed, will ‘harrow’, typically, 40 square metres over the rise and fall of a tide. Seagrass beds flourish in relatively shallow, sheltered bays and alas, enjoy the same merits that make for a good anchorage!

For a generation now, Advanced Mooring Systems (AMS) have been trialled around the world, particularly in North America and Australia. The outcomes have been mixed. The options have usually been different adaptions of a helical screw into the sea floor, rather than a concrete block or an anchor, together with a floating rode, either a chain whose weight is supported by small floats or one made of synthetic elastic or rubber. All of these have proved to work better in waters with a lesser tide range and moderate wave depth. There is no ‘one size fits all’ with AMS; they need to be designed to cope with the specific conditions of the site in question. They are expensive to make and need regular maintenance; the synthetic materials do not weather well and organisms are prone to grow in between the fibres and weaken the elastic. The need for reliability of the installations is emphasised by the high value of the vessels using them and the Insurance implications.

The ReMEDIES project sets out to square the circle by finding solutions to all forms of anthropomorphic damage to Seagrass, exploring the most effective means of preventing it, and then seeking the co-operation of the recreational boating community. To that end The Royal Yachting Association and its environmental programme, The Green Blue, who along with the Ocean Conservation Trust and the Marine Conservation Society
are partners in the Project, are working with many local stakeholders to identify their needs.

Persuading chart makers to plot the Seagrass beds in question on Marine charts is an early initiative already under the microscope.

Pollution in its many forms

During the past year the Solent Protection Society (SPS) has been investigating the impact of pollution on the Solent. This is a huge subject covering everything from shipping to plastic, sewerage to chemicals, noise to pleasure craft disturbance. We have looked particularly at how pollution gets into the Solent and what action is being taken by the various agencies involved. This has also meant looking at what comes down the rivers and out of the many outfall pipes that discharge into Solent waters.

Water Quality

We are all familiar with beach water quality monitoring by the Environment Agency (EA) which is the prime government body charged with checking water quality round our shores and in rivers. These reports, usually available weekly online (except in this Covid year where they started late and are monthly at present), are produced between May and September. The beaches are not monitored at other times and there are large stretches of the Solent where there are no designated bathing beaches; the western Solent for example. Here some monitoring is done by the EA but the results are usually contained in annual reports published retrospectively. They do however give a guide to trends. England’s rivers, lakes and coastal waters are as polluted as they were four years ago, with only 16 per cent achieving good ecological status, according to government data published in September.

Drainage Systems

Combined Sewer Outfalls (CSOs) are largely part of the sewerage system controlled by Southern Water though some may be private. There are hundreds of these CSOs around
the Solent. Most of the drainage systems in the Solent area are combined systems, that is sewerage water and rainfall flow through the same pipe. Consequently when there is a
discharge, say during a storm or if there is a malfunction, then diluted sewerage comes straight into the river or sea causing pollution. As summer storms have increased, this has been happening more frequently and may on occasions breach the legal limits on the number of times this is allowed. Many of these outfalls are not monitored. Southern Water monitors the main ones and has to report on discharges which are picked up in annual reports by EA. We still await the Water Company Performance reports for 2019.

The main culprits are increased levels of nitrogen and phosphorous, with nitrates in particular enriching the water too much causing green algae blooms. These starve the water of oxygen with the inevitable knock on effect on marine life and plants. Not only does this pollution come from sewerage but even greater amounts come from current and historic fertilizer use on farmland and other sources, all of which eventually washes into watercourses. According to reports commissioned by the Solent area local authorities, the bulk of the nitrate content of the Solent waters comes from unspecified ‘coastal background sources’. While much of that background will be from natural sources, we suspect that a significant proportion is likely to emanate from the long sea outfalls which discharge into the Solent. In the case of Langstone Harbour, we understand that it takes eleven tidal cycles to completely flush and with the overall flow of water eastbound through the Solent relatively slow, much of the material dispersed from these outfalls will remain in Solent waters for many days, moving backwards and forwards as it slowly disperses on the tide.

Nitrate Neutrality

House building in the Solent area has been on hold for most of the year while councils look for ways to make new development ‘nutrient neutral’. Natural England produced guidance in June for how new developments could theoretically achieve “nitrate neutrality”. It does not, of course, do anything to improve an already bad situation but it is better than nothing.

We remain seriously concerned about the volume of new housing proposed. The direction set by the new white paper on Planning for the Future, currently under consultation, suggests that house building in the Solent area will both increase and accelerate. Without significant upgrades to the waste water treatment network and the adoption of sustainable drainage systems on new developments, the risk of unconsented storm discharges from outfalls will only increase.

Addressing the Nitrate Pollution Issue

There are a number of potential options identified this year.

  • Acquire farmland in a river catchment area and take lower lying fields out of agriculture and ‘re-wild’ it. This method has been championed by the Hampshire and Isle of Wight Wildlife Trust (HIWWT) who have already used a government loan to acquire a farm on the Island. This will be taken out of production to generate “nitrate credits” which HIWWT can sell on to developers to offset the nitrate produced by their development. The profit made will enable HIWWT to pay back the loan and generate funds for the charity.
  • Increase the capacity and efficiency of the wastewater treatment network, improving the capability for handling peak storm water discharge events.
  • Continue to improve farming methods to reduce nitrate runoff. Over recent decades the farming industry has made significant progress in improving the sustainable use of fertilisers on farms and it is likely that much of the farm sourced nitrate load entering the Solent is historical. The nitrates being released into the ground from agricultural land take years or decades to finally leach through into the watercourses.
  • Strengthen Planning policy to ensure that more areas are protected and that building of housing is more tightly controlled with infrastructure contributions increased to assist with the improvement of CSOs.
  • Increase the mud flats and sub-sea plants like sea grass which, along with oysters, are proven absorbers of marine pollution, by vigorously protecting and perhaps expanding the marine protected areas around the Solent coast.

This is an extremely complex issue both legally, environmentally and technically, and there are certainly no quick and/or simple solutions. Each of the above options will play a part, but more effort and investment is needed if we are to turn neutrality into a positive decline. Some of this will require further legislation by government and some of it will inevitably mean increased water bills.

The ‘rewilding’ of farmland to generate nitrate credits has already been used by Fareham and Havant Borough Councils to kick start new housing development and in September 2020, the UK government approved the investment of £3.9 million to set up a first-of-its-kind national online ‘nitrate trading’ auction platform. This is a worrying development since SPS believes that any mitigation actions for housing development around the Solent should be taken for the benefit of the local area.

While the objective of ‘re-wilding’ farmland is admirable, the benefits are unlikely to be seen in our lifetime. What we will see, however, is the impact of the additional development which the ‘nitrate credit’ approach will now permit. The problem for the Solent and its wildlife will get worse, not better, for the foreseeable future.

What actions can SPS take?

SPS has limited resources but we can continue to monitor the reports that are produced by the various agencies and apply pressure where we find objectives are not being met.

We can press for further legislation along with the many other specialist conservation groups who share the same goals.

We will try during the coming year to draw our monitoring into a form which illustrates the trends we find around our precious Solent.

The secret’s out!

Hampshire & Isle of Wight wildlife Trust has been awarded a £640,300 Heritage Lottery Fund (HLF) grant through the National Lottery to deliver a new programme called ‘Secrets of the Solent’ (SOTS) over the next four years.

5.1 Secrets of the Solent PHOTO Seahorse and seagrass CREDIT Julie Hatcher
“Seahorse and Seagrass” © 2013 Julie Hatcher

Thousands of people live and work along the coast of the Solent, which supports important industries, fisheries and leisure businesses, and many more visit every year. Yet very few are aware of the incredible, hidden life under the surface, including beautiful seagrass meadows, chalk reefs, seahorses, thresher sharks and cuttlefish. Fewer still are aware of the threats that our Solent’s habitats and species face.

The aim of ‘Secrets of the Solent’ is to raise the profile, appreciation and understanding of the marine environment in the Solent, so that, in turn, its coastal communities can develop a sense of ownership, benefit and a desire to protect it. The project is in its initial phase at present. Secrets of the Solent will include the development of various creative ideas in order to build an understanding of the diversity and importance of the Solent’s marine wildlife. We are also trying to change public understanding of its locally-sourced seafood, and help increase the demand for those seafood species that are mainly sold abroad due to the lack of a market in this country. “Lives of the Solent” is part of the campaign that will bring an exhibition and photography project showcasing the lives and stories of those who work on the Solent.

One of the main ways the Trust is planning to achieve its aims is through creating the new role of a Marine Champion. Marine Champions are proactive, enthusiastic volunteers who want to give their time to inspire others to care for the Solent. Marine Champions will receive training to deliver a programme of inspirational and engaging marine activities that raise awareness about the importance of the marine life in the Solent. Secrets of the Solent will also be establishing a Marine Champion schools’ network in the years to come.

The Trust has already recruited Emily Stroud as Community Engagement officer for the project and look forward to welcoming its Project Manager, Rachel Bryan and Communications Officer, Sophie Evingar, at the beginning of October. Tim Ferrero, who has been working for the trust some years now, will be helping alongside the project as Marine Conservation Lead.

If you would like to find out more about the project  or would like to volunteer, please email Emily on emily.stroud@hiwwt.org.uk.