The 'Battle of the Brook' returns on April 20th over flooding and sewage fears regarding the Lidding Road Garages planning application

 

One of several teenagers seen crossing the Wealdstone Brook recently - if they fell in the water they could swallow something very nasty

A comprehensive objection has been submitted on the Brent Planning Portal to the Lidding Road Garages Planning Application. The Planning Committee will consider the application next week (Wednesday April 20th) after its deferral to consider a report from Thames Water.

Planning Officers are recommending approval LINK .

Comments can still be made on the Planning Application HERE

 

LIDDING ROAD GARAGES PLANNING APPLICATION number 21/3248  APRIL 2022

 

The Wealdstone Brook is a river that starts from a spring on Stanmore Common in Harrow and runs through Harrow, into Brent near Woodcock Park in Kenton and then onto the river Brent beyond Wembley. By the time water enters the London Borough of Brent at the cross roads of Kenton Road and Kenton Lane it is already seriously polluted and reading counts taken of the E.coli bacteria in the water at the end of Lidding Road in Kenton, were one of the highest recorded from waterways in the London area. E.coli is a naturally occurring bacterium that is found in the human gut and is therefore an indicator of foul raw sewage in a water course.

 

This serious level of water pollution is due in part to known and unknown misconnections of the foul surface water and foul raw sewage water connections throughout its course through Harrow and the additional misconnections in this part of Kenton, Brent. Under severe rainfall events the Wealdstone Brook quickly fills to its maximum capacity before it reaches Woodcock Park and, due in part to poor maintenance, blocked and damaged foul surface water and foul sewage drains, the areas around the Brook quickly get flooded and badly polluted. The most recent recorded foul raw sewage overspill was from the manhole on the grass area at the end of Lidding Road on the 5^th October 2021. This raw foul sewage over spilled onto the grass area, onto the area next to it known as the Legion Hall site and then into the Wealdstone Brook.

 

The Wealdstone Brook was an earth bank water course and there are numerous recorded flooding events between 1927 and 1981. In 1977 on the 16^th and 17^th August the Brook burst its banks and the whole surrounding area of Kenton was flooded including numerous residential properties. Following this 1977 event, works were undertaken along the length of the Brook up to and including the junction of the Kenton Road/Kenton Lane interchange – in other words mainly on the Brent side. These works included the widening, deepening and brick-walling sections of the Brook from Woodcock Park down to Wembley. The aim of these improvement works was to increase the capacity of the Brook and to speed up the flow of the water. An engineer’s report at that time indicated that these improvements would alleviate problems of flooding for 50 years – and that was 43 years ago.

 

The Wealdstone Brook is simply incapable of coping with the expected water run-off during storm events because it is, according to a recent Thames Water engineer, attempting to operate at over 130% capacity during severe weather events. There is an important difference between the Wealdstone Brook over-spilling its banks and the flooding which occurs around the Wealdstone Brook during severe weather events. This distinction is important in the light of the recorded history of the Brook. As stated earlier, the Brook starts its life from a spring on Stanmore Common in Harrow and continues to receive surface water from several sources as it runs towards the river Brent:

 

1.    Surface road drains taking rain water from roads and into the Brook. Most of the outlets of these drains can be seen on the sides of the Brook and most are at a low level where their outlet enters the Brook. Many are blocked with debris due to poor maintenance and soon become unable to discharge when the flowing water level in the Brook rises.

2.   Water run-off from saturated ground – such as the parks, school grounds as well as gardens which abut the sides of the Brook.

3.   Damaged, broken and leaking clean water drains.

4.   Misconnected foul sewage water and surface water pipes which connect to the surface water drains as in 1).

5.    Springs

Even in the driest of summers and the coldest of winters, water continues to flow in the Brook.

 

It is when there are torrential downpours and storm like conditions that we see the full force of the Brook. Within 30minutes of a storm event in the NW London area, the Brook can be full of water moving along it at a rate of 20 tons per second. In these situations the Brook is at full capacity when it hits the culvert that runs under the Kenton Road/Kenton Lane interchange and the roads around here become flooded. The poorly maintained road drains cannot cope and cannot discharge into the Brook. By the time the water reaches the Falcon Way culvert it is also full to capacity. Again, road flooding around this area and around Lindsay Drive roundabout occurs for the same reasons. These are all HA3 0 areas of Kenton. If any problems occur further down the Brook such as blockages of the road and railway culverts or the opening of the sluice gates on the Welsh Harp, then the flow of water in the Brook is slowed resulting in areas around the Brook higher up flooding even more severely.

 

Flooding from the Wealdstone Brook is therefore a more complex issue than simply saying that the Brook is overflowing its banks. It is a combination of hydrology issues which vary from event to event and include such factors as the direction of the weather storm event, the intensity of the downpours, the length of the downpours and, crucially to begin with, the state of the drains. Once a storm event has started both surface foul water and domestic foul water sewer drains quickly become full, house drains overflow and the mixture of these waters pollutes the surrounding land and intensifies the pollution of the Brook.

 

The main Wealdstone Trunk Sewer, which follows a similar path to the Wealdstone Brook through Woodcock Park and onto the northern section of the grounds of Uxendon Manor School, has been known to discharge its contents from 6m underground to well over 3m above ground during severe storm conditions. All this foul and surface water attempts to flow into the Brook.

 

To put it bluntly, the drainage infrastructure in the area simply cannot cope and is not fit for purpose. For the Environment Agency and Thames Water to say that housing developments close to the Brook can tap into the present infrastructure is to ignore the numerous occasions that Thames Water and Lanes for Drains have had to clean, repair and replace various pieces of drainage pipework in the area in the past few years. And to attempt to build on and next to the present drainage infrastructure as suggested in the Lidding Road garages development proposal (Planning Application 21/3248) would land Brent Council with a substantial structural and economic ongoing problem which would be both a disaster for the residents of these new builds, the residents in the surrounding area as well as an ongoing and increasing economic burden for the Council tax payers of Brent Council. Hash Patel, a past Principal Engineer, Transportation Service with Brent Council, following flooding around the Brook on Wednesday 26^th August 2015 and Wednesday 16^th September 2015 stated the following:

 

“Regarding the River Brent and Wealdstone Brook, I am not aware that surface water has topped the banks (of the Brook). I am aware of flooding in your catchment and majority is related to inadequate capacity in the public sewer network” (my emphasis)

 

Thames Water knows it has to divert the damaged, broken and dysfunctional Victorian sewer pipe that runs from Woodgrange Close, through Woodcock Park, across the green field sites at the end of Lidding Road, through the back gardens of numbers 9 to 14 Brookfield Crescent and onto the manhole junction in Brookfield Crescent, before any works can take place on the site of the old Legion Hall and the grass area at the end of Lidding Road. This would be a very expensive piece of restructuring work. Best not to let them pass the buck to Brent Council.

 

It is wrong to consider housing developments in a flood plain zone 3 area and it is wrong to build over foul water sewers and surface water sewers. The Environment Agency and Thames Water are wrong to approve to the proposed housing development at the end of Lidding Road (Planning Application 21/3248). They are, in my opinion, acting irresponsibly.

 

Brent Council declared a Climate Emergency in 2019 (www.brent.gov.uk/climateemergency) and their pamphlet ‘Nature, green space and the climate and ecological emergency’ should surely be the foundation and driving force in the local Planning agenda. ‘Protect the remaining green spaces, support biodiversity, stop flooding or reduce their severity by preventing surface run off’ – all good intentions which need to be put into practice.

 

An Independent London Flood Review has been announced (Wednesday 22^nd December 2021) into the flooding events of July 2021. The review seeks ‘to better understand the extent and causes of these floods, to assess how the drainage systems performed, and to recommend how the increasing risks of future flooding events can be managed.’

 

‘The review, which has been commissioned by Thames Water, will play an integral part in ensuring that the company future proofs its infrastructure to protect its customers, their communities and the environment as such severe weather events look set to become the norm across the UK.’

 

‘The review will also play an important role in improving the collaborative working between all parties responsible for managing future flooding risks. As part of its focus, the review will provide insights on London’s wider drainage infrastructure and broader recommendations that could be adopted by all organisations with surface water responsibilities. It is anticipated that the review will take no more than 6 months with interim reports published as it progresses.’

 

It would be prudent of Brent Council Planning Committee to await the findings of this review in areas where flooding has occurred and is occurring not just in severe weather events but under normal rainfall conditions. This should be particularly applied to areas designated as Flood Zones 3a and 3b by the Environment Agency such as in the Lidding Road garages Planning Application 21/3248.

 

‘This Independent Review will also assist with Thames Water’s role (as a Risk Management Authority) in supporting Local Authorities in undertaking their flooding investigations as required by Section 19 of the Flood and Water Management Act (2010).’

 

‘As part of its Independent Review this inquiry will examine the flooding mechanisms and consider the performance of drainage systems against design standards.’

 

This will hopefully set a standard whereby Brent Council Planning Officers and Brent Council Planning Committee members can assess whether a housing development such as that proposed at the end of Lidding Road meets the necessary flood risk assessment standards or is too risky to consider until major changes have been undertaken to the surface water and foul sewage water drainage infrastructure in the area of the proposed development.

 

Finally, I would like to conclude on the assumed role of the Environment Agency (EA) with regards to the Wealdstone Brook and its maintenance including its banks. The EA claim in an email letter to John Poole dated 28^th April 2021 that they do not own the Brook and are not responsible for its maintenance including the banks of the Brook. The EA claim the maintenance is the responsibility of the riparian owner where the banks are owned by the landowner which in the case of my garden would be me. There is just one problem with this approach to the responsibility for maintenance and repair and that is that the EA does not allow me to enter the Brook to carry out any necessary maintenance or repair. The other issue to do with this denial of responsibility from the EA and delegation of responsibility to riparian owners is that Brent Council would have to take over stretches of the Wealdstone Brook and its banks where Brent Council owned land joins the Brook or where the Council owned properties with gardens end at the Brook since they would be designated the riparian owner. This is particularly relevant in the case of the Planning Application 21/3248 since Brent Council would be deemed to be responsible for the maintenance and repair of the Brook and its banks from the footbridge near the Woodcock Park Mural, through Woodcock Park, past the end of Lidding Road, past the site of the ex-Legion Hall grounds and down to the Falcon Way bridge at least on the Uxendon Manor School side of the Brook. Needless to say, if this was proven to be correct this would have very serious financial implications for Brent Council.

 

References:

 

BRENT COUNCIL – Flood Risk Management Strategy – Managing the Floods Risk in Brent - 2015

GREATER LONDON COUNCIL – Public Services and Safety Committee Report (30.09.77) – from the Director of Public Health Engineering  - Flooding on 17^th August 1977.

MINISTRY OF AGRICULTURE, FISHERIES AND FOOD – Departmental Investigation into Flood Warning Arrangements in North West London – Report – (25^th April 1978)

GREATER LONDON COUNCIL – RIVER BRENT FLOOD ALEVIATION SCHEME – ENGINEERS REPORT – MAY 1982 –WEALDSTONE BROOK.

HALCROW REPORT – The Environment Agency Thames Region – Wealdstone Brook Investigations – Scheme No 3721 – February 1999

ENVIRONMENT AGENCY OPERATION AND MAINTENANCE MANUAL FOR RIVER BRENT FLOOD ALLEVIATION SCHEME – WEALDSTONE BROOK VOLUME 3 (Contract no.BD3) LEDWAY DRIVE TO KENTON ROAD – January 2002.

WATER FLOW RATE (m3/s) READINGS OF THE WEALDSTONE BROOK FROM THE UNIT AT THE JUNCTION OF KENTON LANE AND KENTON ROAD – from 30^TH November 1976 to 14^th November 2020 DURING SEVERE WEATHER EVENTS.

SUSTAINABLE DRAINAGE SYSTEMS: WRITTEN STATEMENT-HCWS161 made by Eric Pickles (Secretary of State of Communities and Local Government) – 18^th December 2014.

NOTES FROM THE KENTON DRAINAGE MEETING HELD ON WEDNESDAY 12^TH OCTOBER 2016

Water Industry Act 1991 – Chapter 56 – Sewerage Services – as amended.

Wealdstone Brook Water Quality meeting Thursday 22^nd August 2019 which includes a map of all the misconnections of foul sewage water pipes and surfaces water pipes known at that point in time in the Harrow area.

THAMES WATER – Building over or close to a public sewer – undated but updated on a regular basis on the Thames Water website.

PINNACLE CONSULTING ENGINEERS – PROBABILITY OF FLOODING – A flood risk assessment revision 1 as part of the Planning Application for temporary classrooms on the Uxendon Manor School site – undated but probably around 2015 and includes a detailed Thames Water Drainage and Water Enquiry of the area around the school.

Flood Risk Assessment – Uxendon Manor Temporary Classrooms – April 2015 – Price and Myers – contains important information with regards to flood risk assessment in the area of the proposed Lidding Road development.

Email correspondence with Hash Patel, Principal Engineer, Transportation Services, Brent Council September 16^th 2015.

London Flood Review (https://londonfloodreview.co.uk/) December 2021

Environment Agency email from Catherine MacDougall – Asset Performance Team Leader (Colne, Brent and Crane) dated 28^th April 2021 (ref: HNL 12715 HH) – to John Poole.