A plan by Thames Water to drive a 15km tunnel through the area, digging up nature reserves and a park, has been slammed by residents.

The scheme would carry treated sewer water from the Mogden works to be discharged into the River Thames upstream of Teddington Lock.

The idea of pouring treated sewerage into the river has caused anger, however revelations around the tunnel scheme are causing even greater alarm.

At the same time, campaigners have accused Thames Water of deliberately holding back information from hundreds of thousands of affected residents.

Route of the tunnel from Mogden sewage works to Teddington (Credit https://www.savehamlandsandriver.org.uk/)

The tunnel construction would involve many thousands of HGV movements and include the digging of at least six shafts at points along its route.

The first of the shafts on the route from Mogden to the Thames would be at the Northcote Avenue Recreation Ground, alongside the River Crane between Isleworth and Twickenham. Residents have been working to turn the area into a nature reserve.

The second would be in or close to Moormead park in East Twickenham, which has a children's playground, tennis courts and is earmarked for a new community building and café.

The third would be on the banks of the Thames close to the historic Ham House, which is a National Trust property.

There would be three shafts in the Ham Lands nature reserve, which run alongside the Thames, with the tunnel discharging the treated sewer water into the Thames via a fenced concrete bunker upstream of Teddington Lock.

Typical shaft used by water companies (Credit https://www.savehamlandsandriver.org.uk/)

A residents' group called Save Ham Lands and River has been established to fight the scheme. It has formed an alliance with a raft of local resident and community groups.

The group warned: "During the approximately 3-year construction period there will be 13,000 HGV movements on Kingston, Ham, Twickenham and Hounslow residential roads.

"The tunnel would be bored at a diameter of 2.2m and would be excavated using a tunnel boring machine.

"It would have eight 10.5m diameter shafts along its route; one at Mogden Sewage Works, one at the discharge location and six intermediate shafts.

"An area equivalent to the size of half a football pitch would be required for each shaft construction site, which would include works cabins, a large, tracked crane, tunnel boring machine, storage for tunnel and shaft segments, and a soil tip for 24-hour tunnelling and subsequent removal by heavy goods vehicles (HGVs).

"In total there would be 12,700 HGV movements on local residential roads for the transport of soil from shaft and tunnel waste, delivery of shaft and tunnel segments, concrete, large cranes, and tunnel boring machines."

Campaigners argue the scheme would be a disaster for the Ham Lands, which are recognised as a Metropolitan Site of Importance for Nature Conservation.

They said: "Ham Lands is a beautiful local nature reserve, is 72-hectare, and lies in the bend of the River Thames between Richmond and Kingston.

"The site is a mix of habitats, mainly woodland, scrub, grassland, and wetlands, that contain a wide diversity of plants and animals, including numerous rare species that are hard to find in London. There are meadow wildflowers that attract bees and butterflies, and the reserve is teaming with bird life."

Location of the shafts along tunnel route (Credit https://www.savehamlandsandriver.org.uk/)

It is suggested that the scheme construction, with enabling works, could affect as many as 400,000 people.

Several local organisations, including the Broom Water Association, Teddington Bluetits Open Water

Swimmers and Dysart and Burnel Resident Association have combined forces to fight the scheme.

They have won support from the Richmond Society, Friends of Moormead Park, and several groups engaged in the preservation of Ham Lands. 

Support is flooding in from river users including the Skiff Club Twickenham Rowing club, Richmond Yacht Club and Twickenham Canoe Club.

Paul Tippell, a Charted Engineer, who is one of the campaign founders, said: "The full extent of what's being proposed is quite shocking.

"Not only are there much better alternatives, but the destruction of the environment on Ham Lands, Moormead Park in St Margaret's and Northcote Nature Reserve in Isleworth, plus the degradation of river water quality are quite unacceptable."

Moormead Park could be used as location for tunnel shaft (Credit https://www.savehamlandsandriver.org.uk/)

He added: "To cap it all Thames Water's community consultation process so far has been really poor.

"Of the 400,000 people who live close by the planned works, virtually no one has any idea about exactly what this proposal entails.

"The details were never shared at any of the consultation events that were held and those who are now becoming aware of it are quickly willing to support the campaign group and the petition that's up and running and has just passed 20,000 signatures.

"Thames Water are still refusing to provide us with the location of shafts and construction sites.

"It is very concerning that Thames Water has chosen to hold back this vital information on construction and ecological destruction from the public and local authorities."

Thames Water said: "We're still in the very early stages of consultation and design.

"At this early stage, we have not yet confirmed the exact locations for shafts and access points associated with the proposed river abstraction scheme in Teddington.

"Assessments are still ongoing and we will be sharing more information with communities and stakeholders in the autumn."

More details - https://www.savehamlandsandriver.org.uk/