A TALE OF TWO HARBOURS

The harbours of Poole and Chichester are much-loved by boaters, but how often do we actually think about the state of the water around us.

Proof that ‘it can be done’. Without any break in service the old sewage plant at Woolston was replaced by the new, whilst sticking to the same curtilage. Image: Dougal Henshall

Boats, sand bars and beaches, Poole Harbour is a glittering jewel in the crown of the South Coast. Image: Steve McKell / Shutterstock

Earlier this year we looked at the parlous state of our coastal waters, given that the rivers that feed down into the estuaries are being flooded with untreated sewage.

In the last two years there has been a huge increase in not only the numbers of such discharges, but in the duration of these so called ‘legal’ overflows, with the result being that some of our most cherished sailing areas are starting to resemble a toxic soup.

This worrying aspect is made all the worse by the effects of climate change, as rising temperatures are heating up the shallow inshore waters to provide a fertile breeding ground for a number of unpleasant forms of bacteria. This is not exactly the news that the users of our coastal waters would want to be hearing, given that we are not always ‘ON’ the water but often ‘IN’ and what is more, in over our heads.

With so much of our leisure boating activity focused on the central south coast, two of the great attractions of the area for people wanting to get afloat, be that on a paddleboard, a sailing dinghy or a powerboat, are the great harbours of Poole and Chichester.

Building targets Both are stunning locations, wide and relatively unspoilt expanses of shallow water that are a magnet for wildlife and water users alike. The vast majority of users understand the need for the rules that govern our use of these popular spots, but sadly some of the services that support the area have a less than caring outlook.

Chichester Harbour is probably the area at greatest risk, as Sussex has found itself caught between a rock and a hard place. There are government targets for the building of new houses, yet much of the area is covered by the South Downs National Park, which forces more of the building to the south and west of Chichester.

However, the four water treatment plants that serve the region, Chichester, Thornham, Lavant and Bosham, are all recognised as ‘Environmentally Constrained’, meaning that they are already operating at close to maximum capacity.

The building of more houses will just make the situation worse, with a recognition that the options are limited. Already there is talk that the permits which currently allow Southern Water to legally dump waste might need to be eased, whilst another option is to turn the clocks back by creating a number of long pipes that would allow the waste to be discharged further out at sea.

Poole’s solutions Yet, in something of a direct contrast, head just 45 miles west to the equally desirable Poole Harbour and the situation is markedly different. Poole really is one of the Crown Jewels of the South Coast, as the 36sq km of mainly shallow waters are widely accepted as being one of the world’s largest natural harbours.

Like Chichester, the natural side of Poole has come under increasing stress in recent years, although with some targeted and very clever help the wildlife is being given a chance to fight back.

Rising water levels are already creating what is referred to as a ‘coastal squeeze’ which has seen a loss of inter-tidal habitat, but this is being countered by environmental groups who are installing pre-moulded rockpools in key locations (the surface of the mouldings are finished off with large size bubble wrap, which creates an uneven surface for the new inhabitants to settle into) and a series of 3D printed artificial reef units.

Some of these have been located by the 1.5km long Training Bank that guards the western side of the entrance to the harbour and are already providing a popular home for many varieties of fish and crustacean. Considerate approach Even in such a sensitive area, many users of Poole and its environs have highlighted the problems caused by various spills and run off, but at the same time there is an acknowledgement that the geographic basin that feeds into Poole is served by Wessex Water, who have shown a consistent and considerate approach to the state of our coastal waters.

Wessex Water has been an active supporter alongside the Dorset Wildlife Trust, with one project already working to improve some 72 hectares of habitat with specific aims of increasing biodiversity. This is just a small fraction of the 1,800 hectares of harbour catchment area that are now being mapped to give a fuller understanding of the biodiversity right across the harbour and the surrounding catchment area.

Before and after: A 3D printed artificial Reef Unit being lowered into position, which then very quickly became a new home to a variety of marine wildlife. Image: Bournemouth University Keeping the rivers that feed into our coastal waters clean is an essential part of improving our marine habitat. Keeping the River Hooke clean benefits everybody and everything in the catchment area. The river joins the River Frome, which then feeds into Poole Harbour. Image: Wessex Water

One of the great attractions of being in the harbour is that feeling of being surrounded by the countryside, which on the less developed southern side comes right down to the water’s edge, but this of course brings the risk of agricultural runoff into the water.

This is another area where Wessex has been active. An earlier upgrade to the water treatment plant in Poole is already removing more than 900 tons of nitrogen per year that would otherwise have entered the waters of the harbour. A further 275 tons have been caught courtesy of a project that now involves some 65 farms that are receiving help and funding to move to better land management practices.

Enhancing the shoreline However, whilst Southern Water continue to feature in the news for their many and varied failings, their own efforts to improve can all too easily be overlooked. Another highly sensitive area on the South Coast had been Southampton Water which, as we saw back in the January issue, was treated as little more than an open drain since the days of the Middle Ages.

Southern Water had a major treatment plant at Woolston, but it needed upgrading, yet at the same time there was insufficient space for them to expand beyond their current curtilage. Even worse, there was no way to divert the current incoming flow of sewage away from the old plant while the new plant was being created.

If these issues were not enough, Southern Water already knew that treatment plants going forward would have even more expected of them, as everything from wet wipes to nitrates would have to be processed and removed. In a quite amazing feat of engineering and construction, Southern Water did not just complete the task without a break in service, but actually enhanced the look of the shoreline with the incredible, futuristic shiny building that houses the new treatment plant.

The whole aspect of the Woolston waterfront would be changed, with the jumble of the old Thornycroft shipyards replaced by smart looking residential buildings and high-rise flats (including what will be Southampton’s tallest building) and then the curved ‘spaceship’ building of the treatment site.

Southern, who has recently been bought up by the Australian Macquarie Group, is now looking to accelerate progress with a new task force aiming to reduce storm overflows by 80 per cent by 2030, with the even better news that much of the progress in reducing pollution incidents will be in place by 2025.

Back to targets This is all good news that will, like the initiatives that are helping out in sensitive areas such as Poole, bring about a much-needed improvement in our coastal water quality.

Sadly, like a tin can that should be in the rubbish, this is a problem that is all too easily kicked away into the long seagrass of the future, as the latest government plans are only calling for a 75 per cent reduction in the ‘most damaging’ discharges with a target date of 2035, whilst 80 per cent of all discharges should be stopped by 2050.

Although this may all seem a long way off, the good news is that work is already in hand to tackle the problems, as in early May Wessex Water announced their storm Overflows plan, which will have monitoring equipment in place on every overflow outlet by 2023 (there are literally thousands of un-monitored outlets across the UK) and just two years after that will have already reduced overflows by 25 per cent.

However, even as this article was being written, the figures for 2021 were released, which show that across the UK there had been 372,000 ‘events’ of untreated discharge that together added up to 2.6 million hours’ worth of untreated sewage flowing into our rivers and coastal waters.

With the summer months fast approaching and a long-range forecast hinting at a protracted spell of warmer than average weather, our two headline harbours (along with every other boat friendly location around our shores) will be full of people wanting to enjoy the water.

All at Sea will be out there with them and should the waters be too dirty and toxic for use, I would expect further pressure to do more for our most important environment to become even more of a pressing issue.