The River Westbourne flood defences, the tale of two boroughs

 An update post by David Walton of FLASK

  

Brent used to have more River Westbourne flood defences but still has some, publicly owned natural parkland flood defences throughout South Kilburn Vale, that were built in the 1950's and 1960's. These flood defences have been incrementally built on since 2000 and the impacts are already being felt.  The new intention is to establish this as a tall building zone as set out in the Brent Local Plan to 2041 which awaits final approval.  Population growth is planned to rise from 6,000 in 2000 to 36,000 by 2041. Brent has no plan to mitigate growing flood risk which is exacerbated yet further by excavating giant underground car parks. A mainline electrified railway luckily severs South Kilburn Vale from the rest of Brent.

 

For its River Westbourne flood defences, the City of Westminster uses complex and expensively engineered solutions built inside its borough boundary, but it also ( cf July 2021 major Incident) clearly relies on Brent playing its full part in the  flood defence of the City of Westminster upstream of the River Westbourne.

 

Westminster has the Carlton Hill natural hill (pending new developments area) which drains down onto the Brent floodplain vale, with Kilburn Park Road on the east bank of the River Westbourne (Westminster) relying on Brent's depleting natural parkland flood defences for safety. Then at the main borough boundary at Shirland Road, Westminster engineered flood defences start and which though of considerable scale failed in July 2021 and will with certainty fail again unless Westminster and agencies look at the bigger River Westbourne flood attenuation cross borough boundary picture. (See key Kilburn Park Road flood defences already removed like the 40 veteran trees roundabout flood defence or the Granville Road park flood defence three-quarters removed).

 

New map fragments recently obtained from Thames Water show how the culvert straightened high speed River Westbourne takes a dramatic giant sweeping curve from Kilburn Park Road into Shirland Road, and at this point (underneath the zebra crossing) also connects to the North West Storm Relief Sewer which heads west down to the River Thames at Hammersmith, while the Mid Level 2 Interceptor Sewer which heads east to Beckon Sewage Works connects to the River Westbourne nearby at the south east end of Shirland Road. Flood protection support is also supplied by two new large flood storage reservoirs underneath Tiverton Gardens and Westbourne Green. Both are rivers connected and were built in 2016 at a cost of £22 million. To quote from this new project’s 2012 description:

 

"The Sewer Flooding History Database (SFHD) lists 105 properties that have a flooding category of either AI or BI; however, it is known that the flooding issues affect many more properties in the area. Optimise (the contractor) are targeted with removing 177 properties from the SFHD flooding register and contracted to remove a minimum of 147 properties.

 

Primarily, the identified flooding areas are located around Formosa Street and Shirland Road. Prior to 2005 the problem was much smaller with far fewer properties affected; however there have been severe flooding events in 2005, 2007, 2008 and 2009. In both areas the flooding occurs incommercial and residential property basements.

 

Having considered a number of options, the preferred option proposed by Optimise is to construct a 20m dia, 20m deep storage shaft in Westbourne Green. From this a 3m dia tunnel will be driven to a 7.5m dia reception shaft in Formosa Street. In conjunction with managing flows at the Kings Scholar’s Pond and at a number of bifurcations in the Formosa Street area this will effectively resolve the flooding issues at Formosa Street. Flows from the shaft in Westbourne Green will be returned to the Ranelagh sewer (River Westbourne) by means of a pumping station with a return pump rate of 400 l/s. The Shirland Road flooding will be resolved by diverting more flow to the Mid-Level 2 sewer and constructing a 20m dia, 20m deep storage shaft in Chippenham Gardens.

 

In order to remove properties from the SFHD it has also to be proven thatthe properties flood due sewer surcharge / local incapacity. This information was collated through existing databases already connected to the properties, and via interviews with current residents in the area. There was an initial reluctance to complete the survey by residents and this was for a number of reasons, including many residents were not living at the properties at the time of the flooding events and property owners do not want their property on a flooding register.  As such, the verified model has and will continue to be used to validate the number of properties that suffer from flooding".

 

The sheer scale of the City of Westminster's engineered flood defences that are place and   being rapidly extended  indicate that the wild River Westbourne is a major environmental risk to lives and property for this entire area of London. Yet this river is deregulated from Environment Agency responsibility and often commercially driven boroughs so Thames Water must work out what to do in an ad hoc and uncoordinated way instead. 

 

The City of Westminster does seem at least to be trying seriously to take mitigating actions to protect its own residents and businesses on a borough boundary frontline siege basis, but these actions have clearly failed to accept this area’s wider geography and factor in the housing infrastructure in Brent’s urban growth zone.  Brent seems to think that leaseholders and tenants in Brent and City of Westminster should 'learn to live with' traumatic flood risk escalation  and then pay the costs created by its tall buildings growth area, built on a flood plain.

 

Liability is being cleverly being passed entirely to leaseholders and tenants for the moment, as this area’s big freeholder housing block owners will just make sure that flood repairs are actioned in a timely manner and that costs are then fully recovered from block leaseholders and tenants. They will be  paying literally forever for the extreme over development of this floodplain. This, when natural parkland flood defences (that Brent is destroying) had proved excellent in protecting South Kilburn and North Westminster for decades.

 

 

David Walton

FLASK (Flood Local Action South Kilburn)

Suggestions for flood mitigation measures in South Kilburn in the face of over-development

 An attempt at an Underground style map of London's 'lost rivers' and sewers (Heritage Magazine)

A follow-up post to  David Walton’s 'After the July floods urgent action needed on the depleted flood defences of South Kilburn as densification continues'. Proposed here are some sustainable environmental actions for Brent Master Developer to apply to its large South Kilburn site.

Brent as the South Kilburn Master Developer relentlessly prepares building designs, complete with planning permissions,  gift wrapped for hard to trace private enclosure, for freehold buyers/ builders on publicly owned existing South Kilburn flood defences.  All this amidst existing publicly owned social housing. Surely it constitutes major government intervention in the markets. the direct opposite of what government claims it stands for?

 

What makes off-shored private equity so worthy of being made this special case?

 

On the South Kilburn floodplain, government has designated a very large site/ growth area/ tall building zone; with 'site allocations’, Brent designed with planning permissions already in place ready for sale to private developers. The key for South Kilburn residents’ human rights, safety and future wellbeing must be that the River Westbourne and its tributaries existence should no longer be ignored by government.  Decision makers are frantically trading proposed new building site allocations with planning permissions in this flood plain zone. A third of England's flood defences are in private hands, but what about the two thirds which are in public hands and under government guardianship?

 

The deliberate denial of obvious flood risk, when comprehensive natural flood defences were designed and were protectively already in place (the estate’s original housing in designed flood protection park land), is an apocalyptic 'cancel- for- market' strategic device not used before in London. And not unlike using inflammable materials to cheaply build new homes or attempting to allow a deadly virus with no vaccine or cure to rip through society for herd immunity, this human exploitation scandal also deserves an emergency re-think, if all buildings in this water world area of London both old and new are not to be, by this environment cancel sleight of hand rendered  'sick buildings' by year 2041.

 

All South Kilburn natural flood defences which have survived this brutal public flood defence's land transfer to the market must in 2021 be strongly protected, highly valued and CIL upgraded as recreation and natural water store public spaces. While flood defences already been destroyed and replaced by new 'sick building private enclosures',  CIL funded replacements nearby must be installed in a new spirit of  real world UK climate emergency action. And why not restore residents on a partnership board for South Kilburn's very large site to steer and oversee the 35+ new 'sites' towards 2041?  The age of highly lucrative ignoring of environmental concerns and residents’ total exclusion to enable  'smooth process', clearly needs to end given the emergency situation which has become all too apparent to everyone living here. You walk past new blocks and smell the damp!

 

A basic principle for the large South Kilburn site, given its extensive flooding history and ever rising floodplain water table, should be that water is retained safely on site and that roads are no longer designed to function as sewage canals bringing ever more water down from Camden and St John's Wood and then exporting that excess on to parts of Maida Vale from South Kilburn land.

 

Living roof gardens, water butts and genuine estate wide active growing initiatives should be urgent policy for all developments (old and new) - the principle being to control water before it overloads London's crumbling Victorian drainage system from this mega density 36,000 new town called South Kilburn ‘Colony’. In Costa Rica a pioneering Earthshot winning project pays local citizens to restore natural ecosystems and has led to incredible levels of environmental protection and awareness. Why is this considered impossible in South Kilburn’s very large site development?

 

 The River Westbourne flows above Sloane Square station

 

1. This 'very large site' of clearances/ new builds ongoing since 2005 is mainly car-free housing given that two underground stations and a rail station are located in this zone. Instead of increasing adopted roads (sewage flood canals) in grids (the current hardscape in Brent’s rigid plan)- perhaps generous scale green, plant growing, active travel routes is the progressive and climate response and the  best way to develop movement and to link this with protecting and improving the plan that currently neglects surviving South Kilburn flood defence parkland?

 

All Brent highways land in South Kilburn tall building zone's 45 hectares can be re-purposed as flood defence active travel, plant growing ,widened green corridors.

 

As well as this being good for Brent taxpayer's long-term, just look at the 'sick buildings' scandals throughout South Kilburn, where for example it now costs more to repair buildings new built on a flood defence than it originally cost to first build them! A ‘flood risk always reduced from now on ‘approach as proposed here would be good for Carlton vale, good for Maida vale, good for Bayswater and good for Knightsbridge, where the River Westbourne and its tributaries flow.

 

2. Building on every South Kilburn space should be seriously questioned.

Where will extra water gathering on this floodplain go if not into people's homes (old and new) given the water always present near the surface? South Kilburn Land simply never dries-out!

 

Government should no longer environmentally cancel the River Westbourne and its tributaries as policy. COP 26 and Brent Councils own long declared 'Climate Emergency' need to become real (not zoned) for South Kilburn peoples’ lives and this estate of 'sites' all too obvious flood risk environment recognised. Note my neighbours’ living at ground level are flooded out and living in temporary accommodation along with many other local flood families. Dehumidifiers are still drying these flats out and it is November!

3. Opportunities to upgrade rather than total destroy South Kilburn's entire surviving rivers flood defence system also include:

a. Making more space for water. Higgins, a developer at Chippenham Gardens village, South Kilburn where the River Westbourne and the Malvern join is building 56 flats on top of this flood risk basin to Brent Master Developers’ design. Local people have managed to protect the historic flood defence local (reduced in size) park also located here (this based on veteran trees being preserved). However, Brent remains rigidly opposed to improving the flood defence 'pond' potential of this green space by expanding its size, scale, space, volume and depth, by re-purposing three adjacent parking bays and then squaring this off as replacement for flood defence land lost to the new Higgins development.

Plenty of children live in flats above and in basements below, the 50 plus Victorian shops of Chippenham Gardens local centre without gardens or balconies. As it currently stands this green space flood defence will be considerably reduced in size by Brent’s over-building ( so no play equipment space anymore) and will also be design ineffective in its core purpose of protecting lives and homes in this densely populated key local centre (where 11 routes and 3+ rivers meet) from sewage flood major risk liability. Given July floods such disregard of this very specific flood defence improvement 2021 opportunity seems reckless and ill advised.

 

b. Give Local Green Space Designation to South Kilburn Public Open Space, Brent Kilburn’s only remaining park scale natural flood defence. This large park forms an excellent rain garden, pooling surface flood waters for a week then gradually absorbing them. Vital to public health and safety of this very large site and clearly should no longer be Brent 'banked' as surplus brownfield flood defence land for sale with Brent building designs/ planning permissions.

This 100+ veteran tree woodland space must be strong protected with a Local Green Space Designation policy by Brent being climate actioned  for 2021. (The grass cutting tractor could also leave 2 metre of space wild around all 100+ trees to better support the local ecosystem and increase flood waters soak-up speeds yet further).

c. The removal of the large roundabout park of 40 trees flood defence on Kilburn Park Road in 2008 which also used to retain, pond and absorb flood waters has as a result become sewage flooded with highly problematic sick buildings instead.

Westminster has a retirement home that has become a ‘development site' with green space opposite this Brent major flood defence loss. Tanked/sealed underground car parks (once pumped of rising flood plain ground water), mean that Westminster developers can send its entire future excessive water problem on and into Brent homes, particularly into a brand new high density housing scheme which Brent has recently purchased! This Westminster 'site' could work well as a new underground flood water storage defence instead. Veteran trees on this site also need protecting.

Beyond this, Westminster is also re-developing its Carlton Vale Estate NW6 high quality social housing- to become towers instead? This re-development will also have a catastrophic effect on Brent's floodplain downstream. especially if the River Westbourne and tributaries remain ignored by all key decision makers as is the case in 2021.

Brent should challenge Westminster on these all too obvious sewage flood liabilities being adversely across borough boundary grown. The National Planning Policy Framework (section 14. clauses 152 to 169) form an excellent starting point.  While in a similar way Westminster should challenge Brent about the sewage flooding of Maida Vale Shirland Road directly downstream of South Kilburn’s large site with many rivers.  

d. If South Kilburn wasn't a developer colony where "development will look after itself" other solutions could be sought. In Slovakia I know a town adjacent to an historic flood risk river where the local council helps fund ground water pumps in all gardens to systematically lower the town's water table. It also encourages flood plain allotments on its land. Pumped ground water is used for gardens, allotments and for domestic toilets allowing substantial savings on water bills for locals as expensive tap water is not being needlessly wasted.

e. De-paving and permeable pavers should be required throughout South Kilburn very large site, with replacement of existing poor design new hard landscapes as a remedial measure. similar to the replacement of inflammable cladding and inflammable insulation retrofit that is already happening.

4. Given there will be five times the number of homes by 2041 on floodplain unilateral forced as South Kilburn - should the only new 'community infrastructure' in South Kilburn be tall building zone housing and a 'go elsewhere' zonal policy for all else even flood defences?

How can local estate people living a multiple excluded/ deprived estate zoned existence be expected as individuals to own this deliberate and knowing major government escalation of estate flood risk rooted in an unreasonable planned choice to cancel environmental underground rivers as environmental realities, for the brutal short term and soon to be permanent crisis economic gains? Why should City of Westminster residents own this growing cross borough boundary disaster either?

Add South Kilburn zone concentrated inflammable cladding, inflammable insulation, inflammable structure, build quality crisis and incremental withdrawal of health/ services-all points instead to a humane rethink of what "South Kilburn people getting what they deserve" should actually mean? The UN has in October 2021 declared the right to a safe, clean, healthy and sustainable environment a human right and is to appoint an expert to monitor human rights in this context of climate emergency.

Is a 6,000 social housing estate set in flood defence parkland in year 2000 set to become a 36,000 new town towered on 45 public owned hectares by year 2041, with no flood defences retained? Or can this part of London do better regarding protecting human rights and reducing exploitations growing forwards?

Instead of the current land war on estate residents, a war on excessive flood plain water needs to be declared. A new urban construction model of flood management, strengthening ecological infrastructure and drainage systems is clearly essential in very large site South Kilburn zone given the catastrophic liabilities and consequences of creating a giant cross borough boundary sick buildings area (the present reckless direction of travel/ let the market decide process).

Cities like Tokyo and Singapore are planned and designed to handle one-in-100-year storms. Why is London captured in such pre-Enlightenment wilful regression regarding its own new building of very large site towns such as South Kilburn Colony towards 2041? Regents Park is an impressive part of the flood defences for Central London, while Kilburn Park (South Kilburn) flood defence for Central London has been totally cancelled for profit. Who is liable in 2021 and who will pay for what happens in the future and the damages caused?  

 

David Walton

 

FLASK (Flood Local Action South Kilburn)

 

 

After the July floods urgent action needed on the depleted flood defences of South Kilburn as densification continues - Guest Post

 Cambridge Gardens, Kilburn July 2021 (Kilburn Times)

The Westbourne 1790

 

 The culverted Westbourne

Sign in the former Bird In Hand Pub, West End Lane
 

Guest blog by David Walton of FLASK (Flood Local Action South Kilburn. The views expressed are those of the author.

 

The raw sewage river flooding 'major incident' of July 2021 in  South Kilburn and North Westminster, has meant that scores of residents are still housed in temporary accommodation, claims are being made and homes are being dried-out and repaired. Why did this happened? Who pays now and for future major floods?

Householders should beware that new experiments, regressions, crisis and disruptions  are being knowingly allowed in specific new city zonings. In starting to examine this 'major incident' covering Environment Agency policies, unsound growth area, tall buildings, very large site zonings, local flood authority responsibilities, planning law and emergency planning,  a complex picture of government and political indifference  emerges with baked-in environment/ climate denial in regard to the South Kilburn Estate version of 'build back better' where five times the number of homes it had in the year 2000 are being towered, forced and packed onto the River Westbourne's flood plain by year 2041.

The key strategic decision change seems to have been around 20 years ago when the Environment Agency chose, as does the Greater London Authority and Brent Council, that developers could totally deny the existence of the River Westbourne and its tributaries running underneath South Kilburn. Note that South Kilburn's river delta shape is still apparent today and also how early nineteenth century maps of South Kilburn show these rivers set in dairy farm fields, rivers which though in culverts for over 100 years now are natural and still very much here, live and ever present however much denied by government, agencies and politicians.

Taking the Environment Agencies lead and despite all too apparent on site water facts, for Brent Local Flood Authority the River Westbourne and its tributaries simply do not exist anymore (see clause 6.55 Brent Strategic Flood Risk Assessment 2007). A Strategic Flood Risk Assessment process is meant in law to be a 'live' document yet seems to have been rather abandoned at Brent Civic Centre. How 'live' these rivers become in the major incident investigation of 2021 for South Kilburn 'very large site' will be public knowledge soon.

For example, of neighbouring local authorities: Kensington and Chelsea Strategic Flood Risk Assessment highlights the River Westbourne as its second major flood risk after the River Thames and marks the entire river course and tributaries from Hampstead Heath down to the Thames at Chelsea. Camden Strategic Flood Risk Assessment map helpfully indicates historic flooding of South Kilburn and maps how the south west of Camden drains down into South Kilburn vale in Brent. The City of Westminster Strategic Flood Risk Assessment map helpfully indicates historic flooding of Chippenham Gardens, South Kilburn located north of the Westminster boundary.

Since first being built on in the mid nineteenth century South Kilburn was notorious for its flood risk to homes and this kept the area unpopular with new houses being difficult to sell and poverty  concentrated there. This memory of urban trauma inspired progressive architects and planners post World War 2 to protect and transform this flood risk and literally bad land by building a new public owned estate of housing for 6,000 people, with social and health infrastructure set in an impressive recreational parkland of public owned flood defences where flood water could stand, pool and be absorbed by woodland environments naturally- a major London success much celebrated at that time.

 

The protection/ sustainability long-term problem for this massive public investment however was that all public owned estate community new diverse specific land uses were and remain unregistered at the UK Land Registry and later 1970's phase built large panel blocks were unmortgageable as they had catastrophic build defects baked-in.

 

From year 2010 the South Kilburn Growth Area with its green parkland public flood defences total removal policies and resultant ever increased flood risk being manufactured, led to a deal being struck with Westminster. The then City of Westminster Plan highlighted the South Kilburn Growth Area policy as being a major risk to its residents. 

 

So, to protect Maida Vale/ North Westminster in 2015 a £17.5 million flood defence mitigation scheme was built by Thames Water in the form of two large underground rivers flood sewage storage reservoirs sited within North Westminster. However, July 2021, one month’s worth of rain fell in one hour and the River Westbourne and its tributaries sewage waters rose above ground on to streets and flowed into ever reduced flood protections South Kilburn and then horror on into £17.5 million extra flood protection designed North Westminster homes as well! South Kilburn is become a sinking sink and is now proof positive that rivers sewage flood risk, crisis impact and misery can't be neatly corporate zoned in by design anymore.

 

Government responsibility finally has to be taken and the River Westbourne and its tributaries need to be recognised as existing acknowledged as a real problem again for politicians, public servants, shell company freeholders and developers. Often already off-shored and hard to trace new owners of South Kilburn enclosures/ towers built on former public owned flood defences already will certainly not accept responsibility for the massive costs involved in totally predictable and accelerating future major flood incidents. After all the Environment Agency ‘disappeared’ the River Westbourne and its tributaries in South Kilburn, so that is the current 'live' get out of jail free card/loophole still in place legally for South Kilburn developers. Instead help-to-buy and affordable rent families will have to pay government backed massive repairs loans and forced to pay increased charges. The parallels here with the ongoing inflammable building materials crisis facing leaseholders and tenants since the Grenfell fire disaster are remarkable - a predatory political forward strategy of government by debt in South Kilburn tall building zone? Build back inflammable, build back no health and social wellbeing infrastructure to be retained and build back wetter!

 

Granville New Homes was built on Granville Road Public Open Space which was designed  as a major South Kilburn flood defence and Higgins are building at Chippenham Gardens in 2021, taking part of another flood fence open space.

 

The positive news October 2021 is that half of South Kilburn’s public owned green flood defences still exist and function (hence not all of South Kilburn was flooded), even though in parallel they are also Brent 'site allocations' in the unsound as proposed Brent Local Plan towards 2041 (where flood defences are all to be denied and total destroyed). Strong legal protection of the remaining flood defence system for South Kilburn is still possible, while flood defences already market destroyed can and should be urgently restored to raise flood protection back to where it was back in year 2000 as the humane bare minimum. What is the massive Community Infrastructure Levy already raised inside South Kilburn from private developers for if not also to reduce rather than grow multiple deprivations for people living in this zoned experiment in mega population density?