Christine Eborall - Ealing Friends of the Earth

Weak front garden regulations make flooding worse

Christine Eborall — Wed, 03 Jan 2024 15:17:18 +0000

In 1995, the Conservative government under John Major designated pavement crossovers as ‘permitted development’. This fired the starting gun on the conversion of the nation’s front gardens to car parks.
Nearly 30 years on, the consequences of this are all too apparent. In Ealing, as in most other London boroughs and urban and suburban areas throughout the country, there are roads where all the front gardens have been paved over. As well as effectively widening the road by two or three times, this transformation has had many damaging consequences (as explained in: Greening Front Gardens).

From the start, these consequences quickly became apparent, yet nothing has been done. The only concession to the numerous problems caused is some additional regulation about flood risk introduced in 2008 for England (see below).

So there’s still nothing to stop the whole front garden being paved or concreted over. And now, that’s exactly what’s happening. Even people who parked in their front garden but had some greenery before are now putting in blanket hard surfacing and removing every hedge and flower bed.

Often, this is so they can home-charge their electric vehicles, which has a lower VAT rate than on-street charging. Perceived ease of maintenance and persuasive deals and special offers from paving contractors and manufacturers also play a part.

In 2008, after serious flooding in some English cities in 2007, additional regulations were rushed through under Gordon Brown’s Labour administration. These regulations say the parking surface must either be porous or have a soakaway area. They’re intended to prevent rain running straight off the front garden, into the road drains and thence to the sewers which, if overloaded, leads to serious and unpleasant flooding of houses and businesses over a wide area. Are these regulations working?

Not well, according to our observations. They’re quite often disregarded. But even if followed, the two options usually offered by contractors, “permeable” paving or a soakaway device, can fail in the increasingly heavy downpours we’re now getting.

“Permeable” paving is a popular and heavily-promoted option. It’s precast concrete blocks, made to look like stone or brick, but with edges designed to create small gaps between each block. The gaps are intended to let rain percolate into the substrate and soil below. But, even if correctly installed, the gaps get blocked quite quickly with debris.

It doesn’t take long for moss spores, weed seeds, atmospheric dust and the leaves, twigs, flower and seed casings from street trees to find their way into the cracks. They’re blown and washed in by wind and rain, and pressed in by footfall and vehicles. This accumulated debris begins to slow the drainage and hold water, creating the perfect seed bed.

Weeds and moss excel at growing fast so it’s not long, even if the surface is swept regularly as recommended, before they make their presence felt. Householders may then use weedkiller, weed-killing sand , pressure hosing, physical removal, or even blocking the gaps with mortar. But without assiduous maintenance it’s a losing battle, so many people just let nature take its course, with an occasional sweep over or hose down to slow the process and look reasonably presentable – for a while.

The end result is that after a period, which can be several years but can be much less, the permeability of this kind of paving is reduced so much that it just can’t absorb prolonged or heavy rain effectively.

The manufacturers may claim that accumulated debris slows but doesn’t stop rain soaking away. Maybe so in large, flat places like car parks. But in suburban front gardens, especially if sloping and with trees close by, much of the “permeable” paving put in since 2008 is just getting too blocked to cope with sudden heavy rain.

The second main option contractors offer is various types of sealed or concreted bricks and pavers or resin-bonded surfaces combined with a soakaway area. These impermeable surfaces are attractive because there are no gaps for weeds to grow, so they offer a neat and stylish look, provide a good parking surface and need virtually no maintenance.

But their Achille’s heel is the soakaway which should be put in stop rain running off onto the pavement. It can be an accessible flower bed, but often contractors offer a soil soakaway area covered by a grille, or narrow gap, usually between the front garden and the pavement.

Even if grilles and gaps are put in correctly, do they work, especially in the torrential downpours we’re getting due to climate change? Often, not well.

This is mainly because, perhaps contrary to householder’s expectations, they do actually need to be maintained! As with “permeable” paving, it doesn’t take long for moss spores, weed seeds, atmospheric dust and falling leaves, twigs, flower and seed casings from street trees to accumulate in the soakaway area. They’re blown and washed in by wind and rain, pressed in by footfall and vehicles which break up the dry leaves, twigs and casings, and even swept in by householders trying to keep the surface looking presentable.

This accumulated debris begins to block the soakaway, and of course gets wet, again creating the perfect growing medium. So it’s not long before the grille or gap becomes noticeably blocked.

This is when the householder should lift the grilles or gap structure and clear out the accumulated debris. But few actually do this. So it doesn’t take long for an unmaintained grille or gap to become more or less completely blocked. That means that all but the lightest rain just can’t flow into it any more, so flows over it instead.

And even if the soakaway is kept reasonably clear, it may not be able to cope with the really heavy downpours we’re increasingly experiencing.

From here it’s a short step to local surface water flooding, more pressure on local drains and sewers, leading to sewage discharges plus more herbicides, microplastics and other pollutants entering local rivers, waterways and groundwaters.

The Government and local authorities need to recognise these realities, as well as the many other reasons why extensive paving in front gardens is making the effects of climate change worse and adding to the poor state of nature in the UK. The weak, inadequate 2008 regulations need to be changed rapidly.

The parking surface should be the minimum necessary and of matrix construction, so that plants can grow in it and there is direct contact between rain and soil. The rest of the garden should be green, and the only hard surfacing the path to the front door.

Photos taken within Ealing Borough.

The post Weak front garden regulations make flooding worse first appeared on Ealing Friends of the Earth.

Greening Front Gardens

Christine Eborall — Fri, 21 Jan 2022 16:44:28 +0000

Everyone with a front garden has a great tool to counter the effects of climate change!

By Christine Eborall, Ealing Front Gardens Project

Like other suburbs, the London Borough of Ealing has a large number of front gardens (about 75,000), but many are paved or concreted over, usually for parking. But when you consider the climate change benefits that a green front garden can provide, paving it over is the last thing you should do!

Paving a front garden causes at least ten major problems (see below). Each will be made worse by the effects of climate change. But each can be dramatically improved or completely eliminated by:

keeping the front garden green – many plants are very low maintenance
“depaving”: taking up most existing hard surfacing – you can do this little by little
for parking, use reinforced mesh just for where the wheels will be when the vehicle(s) are parked
the only hard surfacing being a path to the front door

For guidance, have a look at the front gardens pages of the Royal Horticultural Society (RHS) and the London National Park City websites and at “depaving” projects in L B Lambeth and elsewhere.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

10 climate change problems and why green front gardens help:

Problem 1 – Increased flood risk: every square metre of hard surfacing increases the amount of rain run-off. Even porous surfaces and drainage channels can’t cope with the increasingly torrential downpours that climate change is causing. This leads to flooding and outpourings of sewerage because the road drains can’t cope – we’ve already seen this in London.

A green garden with minimal hard surfacing (just the path) absorbs rainwater and allows it to percolate slowly through the soil, so there’s no sudden influx of water into the road drains.

Problem 2 – Over-heating: hard surfaces absorb heat in the daytime and release it at night, leading to hotter nights in built-up areas. This is the “heat island effect”. It makes town and cities unhealthily hot at night, especially as summers become hotter due to climate change. It also encourages people to install air conditioning – using yet more energy.

A green garden with minimal hard surfacing doesn’t absorb nearly so much heat. Not only that, but the plants in the garden provide shade and cool the air by evapo-transpiration. Walk down any residential street in summer – it’s like a frying pan where the front gardens are paved, but much cooler where there are trees and plants.

Problem 3 – Less carbon dioxide absorption: plants in gardens and trees in streets take up CO₂ during the day for photosynthesis, but many paved front gardens have no plants at all. In addition, street trees and grass verges are sometimes removed to put in pavement crossovers (kerb drops) for parking.

A green front garden can have plants over nearly all its surface, even if used for parking. Add boundary hedges and climbers up walls. It all helps to add to the trees and plants we’re relying on to counter climate change (by sequestering the CO₂created by burning fossil fuels).

Problem 4 – Worse air pollution: paved front gardens next to roads don’t absorb traffic-generated pollution and dust. This leads to higher levels of air pollution, especially from particulates which are known to damage to human health.

A green front garden will absorb roadside air pollutants, particularly if it has shrubs, hedges and trees. Research shows that many hedges trap air pollutants, so a front garden with a hedge reduces air pollution, forming a barrier to help to protect the occupants of the house.

Problem 5 – Water pollution: climate change is increasing rain run-off. Run-off from paved front gardens picks up oil and heavy metals from the road surface plus pesticides, herbicides and other chemicals used in gardens and on pavements. This adds to the pollutant load and poorer water quality in local streams and rivers – in this borough the River Brent in particular.

A green garden with hedges, plants and minimal hard surfacing (just the path) absorbs rainwater and allows it to percolate slowly through the soil. This process helps remove pollutants from ground water as it flows slowly to rivers.

Problem 6 – Loss of biodiversity: not only do paved front gardens have few or no plants and fewer street trees, the soil underneath becomes dry and sterile. The result is lack of habitat and support for all kinds of wildlife – soil dwellers, insects, birds and more – leading to measurable declines in their numbers.

A green front garden with functioning soil and plants supports all kinds of wildlife and adds to the “green chain” of support for the web of biodiversity.

Problem 7 – Less food for pollinators: many paved front gardens have no flowering plants, so provide no nectar and pollen for pollinators. But nectar in urban areas is an important resource for pollinators (which we need to pollinate our food crops!) and gardens provide the vast majority of it, much more than parks and public spaces, verges, cemeteries etc.

A front garden planted with a judicious mix of flowering plants and shrubs can provide nectar and pollen from March till October. Even a few pots with flowers in every front garden can make a big difference.

Problem 8 – Extensive environmental damage: the materials used for paving and concreting front gardens are dredged, quarried and processed. They are then transported over long distances – extremely long in the case of Chinese granite and the currently fashionable Indian sandstone. All this involves massive energy use and causes large-scale environmental damage.

A green front garden uses a much more limited range of materials. Furthermore, it is largely self-maintaining – there’s no need for toxic weedkiller or cleaning products, and no need to replace or repair the surface every few years.

Problem 9 – Subsidence: the soil under paved front gardens overheats and dries out. This can lead to movement of the ground and building foundations, especially in clay soils such as in London. It can be worsened by trees struggling to find water, so their roots grow further outwards and under buildings nearby.

A green garden with minimal hard surfacing (just the path) allows rainwater to sink in, maintaining normal soil structure and hydration for plants and trees.

Problem 10 – Unattractive neighbourhoods: there’s lots of evidence that lack of green space in towns and cities create stress, mental health and societal problems. Entire streets with paved front gardens and no hedges and street trees can look dirty, unattractive and threatening, and contact with neighbours is minimised.

Green front gardens create interest and stress-relieving green space. Plants, especially when in flower, have been shown to lift the spirits, and increase community cohesion by encouraging personal contact between neighbours.

The post Greening Front Gardens first appeared on Ealing Friends of the Earth.