London’s River Water Quality – Thames Vision Framework

London’s River Water Quality

The Water Framework Directive (WFD) aims for ‘good status’ for all rivers (and other water bodies) measured in terms of their chemical, biological and physical condition and quality. Of the river water bodies in London, two are ‘bad’, eight are ‘poor’ and the rest are ‘moderate’. The primary reasons for the failure of London’s rivers to meet WFD standards are: diffuse pollution from road run-off, foul water misconnections to the surface water drainage system, and point source pollution from treatment works. The physical modification of many of London’s rivers by culverting, canalisation, etc. also contributes to the failure to meet ‘potential good’ status under the WFD framework.

 The Port of London Authority’s Thames Vision is the framework for the development of the tidal Thames between now and 2035. The Vision covers goals for growth and actions to deliver these goals. This document covers the context for the Vision today, the goals and priority actions, the governance framework and how progress will be reported. You’ll note that the Port of London Authority (PLA) support the development of the Thames Tideway Tunnel but make no comment on the role of green infrastructure and the benefits to the Thames that can be realised.


Environment – Improved tidal Thames environment

The tidal Thames provides a range of diverse, thriving habitats for many different species of fish, birds, seals and other wildlife. It is home to nine Sites of Special Scientific Interest, mainly inter-tidal habitats. Many of these have further international environmental designations such as RAMSAR Convention wetland sites or European designations such as Special Protection Areas or Special Areas of Conservation. The whole of the tidal Thames in Greater London is identified as a Site of Metropolitan Importance for Nature Conservation, and a number of other Sites of Importance for Nature Conservation lie alongside the river within Greater London (such as Rainham and Wennington Marshes, Erith Marshes, Battersea Park, Barn Elms and Kew Gardens).

There are also a number of sites of borough or local importance, including Blackwall Basin, Leg of Mutton Reservoir, Petersham Meadows and Marble Hill Park, as well as most of the tributaries as they meet the Thames. The Thames plays a crucial role in the importance of these adjacent sites, and they provide additional habitats for some species that use the Thames (e.g. foraging and roosting areas for many birds).

92% of the Port of London Authority (PLA) area is covered by environmental designations of some sort. The latest surveys found over 900 seals and visits from 300,000 overwintering birds every year. Against these positives, there are a number of major challenges to the Thames environment. The PLA-led Cleaner Thames campaign highlights one. Up to 300 tonnes of rubbish is recovered from the Thames each year, with the amount of plastic bottles growing year on year. A study by researchers at Royal Holloway, University of London and the Natural History Museum has shown that up to 70% of bottom feeding fish in the Thames has plastic fibres in their guts, which can then get into the human food chain.

There are more than 50 major discharges of untreated sewage into the tidal Thames each year as a result of the inadequate capacity of the Victorian infrastructure. Despite Bazalgette’s foresight in building a sewerage system that could meet the demands of a much bigger London nearly 150 years on, the system no longer has sufficient capacity.


The Thames Tideway Tunnel will make the river through central London the cleanest it has been since the Industrial Revolution. With more consistent, higher water quality will come more biodiversity. There are already 125 fish species feeding on the abundant invertebrates in the river. The waste water treatment improvements to discharges into the Thames that are being provided by investments by Tideway, Thames Water and other operators provide a great platform for cleaner water and a more sustainable river.

The Thames already has a number of environmental improvement projects like the Nature Improvement Area, Catchment Plans and Futurescape, led by an increasing number of nonprofit organisations and charities such as the Wildlife Trusts, RSPB, Thames21 and Thames Estuary Partnership. Projects are driven and resourced by enthusiastic volunteers up and down the Thames.

As well as a focus on improving the environment, the Vision includes aims to reduce the overall environmental impact of activities on the river. This means compliance with current rules, for example those set by Maritime and Coastguard Agency but also looking to best practice from across the world to encourage innovation and the adoption of new technologies to reduce the impact further, such as on air pollution.

The Environment Agency’s Thames Estuary 2100 programme will be providing improved flood defences across the Estuary to protect the increasing population from the growing risk of flooding due to the effects of climate change. During these works, flood defences will need to be repaired and raised. Changes are expected in the frequency of extreme weather events as a result of climate change.

Vision, 2035

The 20 year Vision will see the river the cleanest since the Industrial Revolution, with improved habitats.

To achieve this goal in a safe and sustainable way, the following priority actions have been set:

  • Build and bring into operation the Thames Tideway Tunnel, by 2021. The completion of this project, extending from Acton in the west to Abbey Mills in the east, together with the Lea Tunnel and the substantial investments in capacity at Thames Water’s existing sewage treatment works, will dramatically reduce both the number and total volume of sewage discharges into the Thames and its tidal tributaries. Cumulatively, this will act as the largest improvement in the water quality of the River Thames within London in a generation
  • Improve water quality by a range of measures including reduced litter in the river. As well as through delivery of the tunnel, this will be achieved by parties working on improvements and best practice through the Tidal Thames Catchment Plan and the Wider Thames River Basin Management Plan. Coordinated action is also required to secure effective management of invasive non-native species (INNS). We also want to see a reduction in litter falling into the river, which is being targeted through the awareness building ‘Cleaner Thames’ campaign that is focusing on plastic rubbish. The Thames Vision can widen the awareness of the campaign, drawing in other Vision stakeholders such as leisure users to reduce or give up single use plastic or dispose of them responsibly. The PLA has consulted on changes to the Thames Byelaws to ensure Class V passenger vessels do not discharge sewage into the Thames from 2023
  • Improve biodiversity of sites recognised for their wildlife interest, and the connections between them. The nine SSSIs along the tidal River Thames are all within the PLA’s jurisdiction. A priority is to get the SSSI sites into ‘favourable condition’, where practicable, so they support more wildlife. The condition of the sites will benefit from more connectivity of habitats across the Thames, for example by looking at new stepping stone sites and managing a group of sites in a coherent way. It is also beneficial to continue to encourage communities to identify with local reserves and sites to protect and improve the access by wildlife, in land-based and marine ecosystems.
  • Encourage uptake of new and green technologies to reduce the port’s environmental impact. With a focus in the first instance on air pollution, we will learn from best practice from across the world to reduce diesel emissions from all commercial vessels that use the river. With an Ultra Low Emission Zone being introduced in Central London from September 2020 – applying to all cars, motorcycles, vans, minibuses, buses, coaches and heavy goods vehicles (HGVs) – river transport will play its part too to reduce exhaust emissions. Whilst the standards for vessels are set by the Maritime and Coastguard Agency (MCA), there is a role for the PLA in exploring how to encourage the move to greener vessels without steering trade away from the Thames. There are other opportunities, such as harnessing the energy source of the Thames that we could also explore. Water source heat pumps are already beginning to take advantage of this (e.g. at Kingston Heights on the non-tidal Thames).


Improving flood management using more natural processes.

One of 5 key aspirations of the London Rivers Action Plan (2009) which was developed to highlight opportunities and provide practical guidance to local authorities, developers, Non-Government Organisations, community groups and stakeholders was to improve flood management using more natural processes. The London Rivers Action Plan was supported by, the then Mayor for London, Boris Johnson, Environment Agency, Natural England, Thames Rivers Restoration Trust and others.  Benefits to integrating green infrastructure into planning are listed as:

  • Flood protection has been improved by working with natural river processes;
  • The combination of the new open river, together with the old culverts, enables the regulation of flows for a range of environmental conditions associated with climate change impacts;
  • Provision of a diversity of wildlife habitats able to support a range of species and a much needed backwater area;
  • Improved community access to nature and an enhanced recreational facility.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s