In our urban environment we see numerous examples of open spaces with hard paving all over them. One of the reasons for this is our insatiable hunger for parking. The earth in our cities is starved of air and water — sacrificed at the altar of our rubber-shod tin cans.

“Ah”, but I hear you say, “we really do need that parking space!”.

Of course, if our city fathers were more enlightened and aimed for better public transportation instead of caving in to the cult of the car, we wouldn’t have reached this impasse in the first place. However, this page is not a rant about ineffective urban planning but about the effects of indiscriminate paving and what we can do about it.

When we pave over open spaces, a number of things happen.

The Water Table Drops Dramatically

This one is pretty obvious and hardly needs an explanation. If the ground is paved, there is no way that any more than a tiny fraction of rainwater will ever reach the soil. In Bombay, there was a time when one could dig a well and hit water not far below the surface. These days, the only reliable wells are the ones that adjoin large green spaces — like the maidans for example.

Other cities are not so lucky and those who live where borewells are common will tell you that the wells need to be dug deeper every year. The water they reach is also an increasingly fickle seam. The demand on the groundwater is constantly on the rise but all that paving never allows it to get recharged.

Egress of Saline Water in Coastal Areas

Freshwater is lighter than saline water

Saltwater is denser than freshwater and forces its way inland below the latter. If the (fresh) water table drops, the boundary between them is pushed deeper inland. Salinity in the soil is not merely bad for plant life but also for construction.

Trees Find it Difficult to Survive

For plants — and especially trees — paving is doubly detrimental. Not only is there very little water in the soil to help them grow but their roots are also unable to breathe. As a result, the trees develop a weak rooting system; it is no wonder so many of them topple over during the monsoons. That many of the avenue trees in our cities are fast-growing exotics, doesn’t help very much either.

Drainage Systems are Overwhelmed

Kalyan Station under water
^{Image source: Wikipedia}

When it rains in an urban area that is excessively paved, the runoff has to go somewhere! That somewhere, is the storm-water system which is frequently unable to cope. This leads to the all-too-familiar floods we see every year.

At best, flooding is an inconvenience but, as the last few years have shown us, it can also be deadly. Corrupt builders, politicians, and bureaucrats are responsible for the rampant encroachment on natural drainage channels in many of our cities. This results in the kind of devastation and loss of life we saw in Bombay (2005), and Madras (2015).

No doubt, in both cases there had been uncommonly heavy rainfall. We must remember, however, that climate change is causing an increased frequency of such extreme events, so it would be foolish to brush them aside as a freak events.

Worsening of the Urban Heat Island Effect

Temperatures are significantly higher in cities
^{Image source: Wikipedia}

Paving is one of the major factors leading to the heat island effect — that phenomenon where an urban area is significantly hotter than its surroundings.

Unlike soil which cools off rapidly when the sun goes down, paving retains heat for longer and then emits it slowly through the night. One of the only ways to reduce this effect is to increase the area under plantation (including on roof terraces). However, as we have seen earlier, that is rather hard to do, when everything has been paved over. It’s a bit of a vicious cycle.

What We Need to do

Of course the very best thing to do is to avoid paving as far as possible. However, there are many situations when we really have no choice. At such times, the least we can do is to use materials and systems to mitigate the problems we cause.

Pervious Concrete Paving

This is a type of concrete where the fine aggregate (sand) is missing so that the concrete becomes porous enough for water to percolate through. This means, of course, that it is not as solid as other concretes and cannot sustain the same heavy-duty usage. On the other hand, it is perfectly usable in areas where traffic density is low or, for example, in parking lots.

Some cities like Portland, Oregon in the USA have experimented quite extensively with permeable paving. Unfortunately, there is little sign of anything even remotely close being done here.

Perforated Paving Block or Grass Paver

These are easily available here but not as commonly used as I wish they were. They are easy to lay and, to my eye, they make a space look much nicer than if were completely covered with a hard surface.

Permeability is excellent but, like porous concrete, it can only be used for low-traffic areas or parking lots.

Tree Guards

If all else fails — and even if not, it is wise to have tree guards which allow the soil around the roots to breathe. This is something that is conspicuously lacking in our cities.Instead, we see a low brick wall made as close to the trunk as possible. Apart from being undersized and ugly, these are also tripping hazards for pedestrians.

It would be so simple, instead, to embed a cast iron tree guard that is level with the pavement. If the city authorities feel that the iron will be pilfered, they can do something similar in ferro-crete. It won’t look half as nice but at least it will be effective.

Green Roofs

While a green roof can’t do very much for the surface runoff and the storm-water systems, it can certainly be help reduce the urban heat island effect.

Planted roofs haven’t caught on too well here as yet. That will not change until waterproofing systems become much more reliable. People who have running battles with monsoon leakage are unlikely to tempt fate.

Conclusion

The situation is far from ideal but it isn’t a lost cause just yet. Given enough awareness and pressure from the general public, things can improve. Organisations like depave, for example, have done this very effectively. They have not only raised awareness in Portland but have even forced the local government to reverse past mistakes.

Maybe it’s time to start something like that in all our cities here as well.

It’s almost a quarter century since I became a practising architect and, although I have been doing pro bono design work over the years, it has always been for people or organizations that know me directly. This way I do no more than a couple of days worth of pro bono work in the entire year.

Starting this April, I have decided to put aside one hundred hours every year for pro bono work. It could be any non-profit although priority will be given to assignments that are connected in some way to the environment or to education.

In the USA, there is an organization called 1+ which asks design houses to donate 1% of their time to non-profit work. That works out to about 20 hours per person each year. They then put people in need designing done in touch with those who do it.

Unfortunately this organization has no chapters in India so it looks like I’m on my own here and will have to rely on my friends, and the readers of this website to get the message out.

Ground Rules

There are a few things to remember and it is best to put them down so there is no confusion later.

• The project and the organization undertaking it must genuinely be not-for-profit.
• It must be for a good cause.
• No single assignment will be allotted more than 40 hours.
• If any travel is involved, it has to be paid for.
• If any fancy presentations have to be made I will only provide the raw design. You do the rest.
• If you want detailed estimates of cost, please get in touch with a builder / contractor. At best, I will be able to give you rule-of-thumb costings.
• I will try and do the required work as quickly as possible but please understand that my paying clients have priority on my time.
• Ultimately, the decision on whether to take up an assignment or not, rests with me.

Please share this page with people you think might be interested. If you do, someone, somewhere will be able to use the information. If it just sits here, nobody benefits.

Many people dream of leaving the city to lead a slower, more meaningful life outside it. Few, however, are able to live that dream. Just a stone’s throw from the [RaBV] bungalow here is a sustainable weekday home of a couple who come into the city on weekends.

Site Conditions

Satellite images of the site showing how the flood zone determined the final house location.

Much of this one-acre site is between 1.5 and 3m above the average water level of River Pej, so during the monsoon, the lower section of the plot is often flooded once or twice for a few hours at a time. The initial plan was to build almost touching the river but that would mean building on stilts. Instead—taking into consideration the high water mark of 2005 which saw the worst flood in living memory—we decided to build on a small rise at the other end of the plot. Thanks to climate change, such freak events as the cloudburst of 26^th July 2005 are likely to happen with increasing frequency and we must understand and prepare for them instead of brushing these facts under the carpet.

Because of the sloping land we have a large basement

The little rise is next to the access road so the approach to the car parking area is a little steep but, other than that, there are no disadvantages. There used to be a shed on this mound so there were no trees that needed to be designed around.

As the building is on a slope, the extra height at the bottom has been used to create two basements. One stores gardening and filtration equipment along with the rainwater harvesting tanks while the other has batteries, inverters and other electrical equipment for the photovoltaic solar panels.

The foundations and plinth of the bungalow being made of local black stone.

Design Considerations for Sustainability

Climate data for the location which helped make a more responsive, passive solar design.

As with the [RaBV] bungalow, the climatic conditions to be considered were hot days and pleasant nights with a strong monsoon. We needed sufficient shade on the South and West sides and this was taken care of with deep verandahs. Air circulation and cross-ventilation were important to eliminate the build-up of hot air. For the most part, roofs are sloping with only a small fraction of flat terrace where the solar hot-water systems are placed.

ShKo Layout Plan

Instead of a typical compact layout, this house was designed as a series of spaces with clear zoning of public and private. When seen from a distance–and a height–it looks like three houses in a cluster rather than just one. Central to all three spaces is the court and the open tank. This is not some amoeboid pool for people to float around with a cold beer but a straight 15m strip for exercise. Oh, and it’s a tank because, well, it’s a tank. Water from here goes to the vegetable garden and to many of the trees on this plot.

The clients, currently in their early 50s, want to spend the bulk of their time here exploring their creative side. Accordingly, one of the major spaces in the house is a workshop to be used for painting, stained-glass making and sliver-smiting. There is also a small study, two bedrooms, a utility room, a living/dining room and a very large kitchen.

Materials & Systems

Exposed brickwork, Mangalore roof tiles and windows made from reclaimed wood.

The foundations were constructed from local basalt and the superstructure from local bricks.We discussed the possibility of using fly-ash bricks but the clients had reservations because of the debate over fly-ash being carcinogenic.

Many internal walls were left un-plastered and the roofs had a steel structure with Mangalore tiles on battens without any under-layer.

One of the old wooden pillars on its granite-clad base.

Doors and windows were either beautiful old ones that were salvaged from demolished homes or were made anew from reclaimed old Burma teak. The credit for sourcing them all goes completely to the clients. They also purchased five lovely old wooden pillars during their travels, which were incorporated into the design. Since these were only 2.5m tall, we made a tapered concrete base which was then clad with the same grey granite as was used for the adjoining parapet walls.

Energy

All the lights are low-energy, mostly LEDs, while the fans and refrigerator are inverter-type so their energy consumption is also lower than average. As these fans are a relatively new product, it remains to be seen if they stand the test of time.

Bath and kitchen water is heated using one solar panel on each of the terraces. There are also twelve photovoltaic solar panels on the roof of the workshop which provide enough electricity to run all the lights and fans as well as some of the appliances.

Water

The rainwater harvesting filter

A good amount of the rainwater is harvested. Some of it is collected in tanks for drinking water throughout the year. This is necessary as the river, though perennial, sometimes contains urea washed in from fields upstream; even though the water is clean enough for bathing and washing, it is not advisable to use it for drinking or cooking. The remaining harvested rainwater is used for recharging a bore-well that is an emergency backup water-source. Whatever rainwater is not harvested either seeps into the ground or flows directly into the river.

Embedded dual cisterns flush the low-flow WCs and kitchen waste water is sent directly into a soak-pit from where it percolates into the ground.

And finally, some more images

Project Participants