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What a stink! Investigating sewage discharges into New Forest rivers

Russ writes:

I’ll start this blog by reminding readers that our mission at Wild New Forest is to deliver high-quality wildlife survey and monitoring data to support wildlife conservation and management, and to inform, involve and inspire people about the wealth of wildlife in the New Forest. However, we will also raise awareness of issues where our own field observations indicate there is likely to be a negative impact on New Forest wildlife. For example, this year we have supported statutory bodies on issues including dogs chasing deer and verge parking, through provision of images and quotes in local and regional media.

On Wednesday 19 August, on a very wet and rather autumnal feeling day, I was walking with my two-year old through Mallard Wood towards the upper Beaulieu River. I could smell the river before I saw it – the distinctive and unpleasant stench of sewage effluent. When I arrived at the riverbank, the flow was fast and a dirty brown colour, with an oily slick visible at the surface in places. Given I was only a few hundred metres downstream of the Lyndhurst Waste Water Treatment Works (WWTW), it seemed reasonable to assume that this was the source of the discharge. I moved downstream, observing the flow (including some overbanking) and took a few photographs. Once it became clear that the pollution was persistent as far downstream as Longwater Lawn, I phoned the Environment Agency and Forestry England to express my concerns.

Photo showing the upper Beaulieu River on 19 August 2020: note the overbanking in the background, dark brown colour, and the oily slick just visible on the surface in the foreground

In the following days a combination of online research, discussion amongst the WNF Facebook community, and a useful phone discussion with the EA Senior Environmental Officer responsible for the New Forest area, revealed some alarming facts: Southern Water, now a private company, operate the Lyndhurst WWTW. In normal conditions, all of the sewage and waste water from houses in the Lyndhurst catchment, combined with surface run-off from roads, enters the WWTW for 1) solids settling and screening (using a 6mm screen), 2) bacterial treatment to remove organic matter, and 3) chemical stripping of phosphate. The resulting ‘secondary activated sludge’ is then removed by tankers for use in agriculture. Southern Water data for 2019 indicate that the Lyndhurst WWTW produces 85 tonnes of raw sludge per annum (dry weight). This is unsurprising when we are each responsible for producing up to 20 kg of sewage sludge per year! The treated liquid effluent is then routinely released into the adjoining Bartley Water, where it joins other small-scale discharges from private residences.

However, Southern Water also have a permit from the EA to undertake emergency storm discharges into both the Beaulieu and Bartley Rivers at times of high rainfall (also called combined sewer overflows - see appended link 1). During these emergency discharge events, once the storm tank is full, then the discharge is only screened for solids and there is no additional treatment. This means that untreated effluent, comprising liquid sewage, chemicals in household grey water, and pollutants running off our roads, all enter the upper river system, pass along the river to the coast, and end up in the Solent and adjacent waters. So, in theory, someone using the toilet in their Lyndhurst home could then go for a walk along the Beaulieu River and watch their dog drinking their own waste, and then drive to the coast at Calshot and swim in it! The effluent is of course massively diluted, especially during periods of high rainfall, but you get the idea.

Although the effluent is diluted during emergency discharge events, they can occur over long periods. For example, the emergency discharge event at Lyndhurst WWTW last week occurred over a period of 16 hours. This is not a new occurrence and is not confined to this location in the New Forest. A 2015 report by Cefas (see appended link 2) indicated that the Lyndhurst WWTW intermittently spilt discharge into the Beaulieu River for nearly 10% of the time in the period 2010-2013. Similar discharges occur at other WWTW in the New Forest, including the Beaulieu WWWT that also feeds into the Beaulieu River and the Brockenhurst WWTW that feeds into the Lymington River. According to a recent nationwide investigation by the Rivers Trust and the Guardian, the sewer storm overflows at the Lyndhurst works that feed into the Beaulieu River are considered to operate too frequently (see screen grab below). The EA have confirmed that the Lyndhurst WWTW is regarded as a ‘high-spill’ works and is one of the worst in the Southern Water region for the frequency of emergency storm discharges.

Screengrab from the Rivers Trust website highlighting the Lyndhurst WWTW emergency discharge into the Beaulieu River, and the subsequent impact on water quality

BBC News online subsequently featured this story (see link below), which followed other news items in national media highlighting the appalling water quality in coastal bathing waters in our region following the heavy rainfall on Wednesday (Surfers Against Sewage and other coastal user groups have long been complaining about these water quality issues).

Three days after the emergency discharge took place, I revisited the upper Beaulieu River with Richard Reeves to look for any evidence of lingering pollution once the waters had subsided. The area immediately downstream of the works still had a detectable smell of effluent, and there were several areas upstream of debris dams where a pale grey (non-natural) surface slick was present on the water surface. Parts of this stretch were restored to a meandering course a few years ago, and as a consequence there were a few bankside pools where overspilling floodwaters had been trapped - these will presumably trap and concentrate any surface pollutants, which is concerning when they often attract livestock and other fauna to drink.

This unnatural-looking pale slick was one of several seen upstream of debris dams three days after the emergency discharge event

This New Forest pony is drinking from trapped floodwaters on Longwater Lawn adjacent to the Beaulieu River, which will presumably contain diluted effluent

It’s worth noting here that the Beaulieu River is part of the New Forest SSSI and, in theory, should be one of the most protected rivers in Europe on account of the New Forest’s status as a Ramsar site, Special Area of Conservation and Special Protection Area (with rivers and riverine species such as Kingfisher cited as protected features). It’s obviously also an important tourist destination, especially this year, with lots of visitors paddling in the apparently pristine rivers and streams.

Southern Water has been in the news several times in recent years as a result of their poor performance regarding sewage discharge in our region. This included a whopping £126M penalty by the regulator Ofwat last year (see appended link 3), for lack of investment in infrastructure and misreporting of sewage discharges in the period 2010-17 – the Beaulieu River was cited in the investigation as one of the sites that was particularly affected. Despite these obvious long-term issues, their Chief Executive took home pay and packages worth over £1M in 2018, and their shareholders pocketed most of the £176M profit. Residents in Lyndhurst and other New Forest villages are therefore paying for a service that clearly isn't being delivered, and will surely be concerned to hear that they (and their pets) are at risk of getting ill from their own effluent when bathing or paddling in local waters!

From a Wild New Forest perspective, we are satisfied that we have raised awareness of this issue amongst the local community, and are hoping to discuss impacts on water quality and wildlife with the Freshwater Habitats Trust, who have provided some useful info on this topic, including the role of all of us in helping reduce the level of pollutants entering our waterways (e.g. see appended link 4). Although we have limited capacity for campaigning work, we will continue to push for further independent monitoring in order to gather evidence that will hopefully see the Lyndhurst WWTW, and others in the New Forest, made a high priority for future investment to reduce the frequency and volume of emergency discharge events in the future.

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