Reduce Hard Paving

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

too much paving leads to a drop in the water table which allows egress of saltwater

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 July 2005

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

urban heat island

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

permeable concrete

Permeable Concrete
Image Soure: Wikipedia

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

grass paver blocks

Grass Pavers
Image Soure: Wikipedia

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

tree guard

Tree Guards
Image Soure: Flickr

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

green roof

Green Roof
Image Source: Wikipedia

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.


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.

SVAGRIHA – a simplified version of the GRIHA Green Rating System

They’re calling it “Small, Versatile, Affordable” GRIHA – a less complicated green rating system for projects less than 2500 sqm. in area.   Quoting from the email they sent me:

ADaRSH (Association for Development & Research of Sustainable Habitats) is pleased to announce the launch of

Small Versatile Affordable Green Rating for Integrated Habitat Assessment

A Rating system for small homes, offices and commercial buildings with built-up area less than 2500sqm

SVAGRIHA is a significantly simplified, faster, easier and more affordable rating system and will eventually function as a design-cum-rating tool. It was required that attention be paid to smaller buildings in India which although have small individual environmental footprints but their cumulative effect is far bigger. SVAGRIHA has been designed as an extension of GRIHA and has been specifically developed for projects with built-up area less than 2500sqm. SVAGRIHA can help in design and evaluation of individual residences, small offices and commercial buildings. The rating comprises of only 14 criteria (instead of 34 of GRIHA) and the interface comprises of simplified calculators. These calculators can be filled using information from construction drawings like areas and quantities of materials. This can be done easily by the architect of the project. Once completed, the tool will tell the consultant the number of points that they are able to achieve in that particular criterion and provide recommendations for any improvements in order to improve the environmental performance of the building.

Process of SVAGRIHA Rating

  • Registration of project with ADaRSH
  • Submission of completed calculators, drawings and other documents as required (quantity estimates) to ADaRSH
  • Assessment/Review as per SVAGRIHA
  • Site Visit and due diligence check post construction (mandatory)
  • Evaluation by GRIHA certified Evaluator
  • Award of Rating.

Note: The site audit to check compliance will be done once the project is complete and all equipment to be verified are installed.

For more information please visit

GRIHA is the national green rating system for India developed by TERI and the Indian Government. I’ve always felt that GRIHA is far more suitable for us than (the more popular & better known) LEED rating system.

SVAGRIHA has just 14 criteria compared to GRIHA’s 34 and can act as a good checklist at the design stage.

SVAGRIHA CriteriaSVAGRIHA point groupsLooking at the point groups, I’m happy to note the weight given to Energy and Water conservation. At the same time, to achieve a rating, the design must achieve minimum standards in all categories. So while they say that 25 our of 50 points will give you a one star rating, adding up all the minimums means you actually need at least 28 points.  And finally, the table below shows the star rating that can be achieved.


Welcome to bT Square Peg

Based in Bombay (Mumbai) bT Square Peg has been creating sustainable designs in architecture & interiors since 1993.  The primary intention is to seamlessly blend practicality & timeless aesthetics with sustainability — the resources on this planet are not limitless.

design principle:
to seamlessly blend practicality, aesthetics & sustainability

Many designers care more about how the job will look in a magazine article—preferably the cover feature—than it does in reality. This often leads to homes and offices that look very dramatic in photographs but don’t necessarily work in practice. Equally, there are clients who fall into the trap of wanting to showcase the latest rage. Both approaches are wrong in my opinion.

The principle here is to keep in touch with current trends and materials without becoming a slave to transient fashions. Ultimately the objective is to create spaces that are—both physically and aesthetically—appealing to the inhabitants.

Featured Projects

[ShKo] Bungalow

Nasrapur, Karjat [2012-2015]

Courtyard and swimming tank seen through a brick jaliWith rooms arranged around an open court that has a swimming tank, this bungalow is the weekday home of a couple who come into the city mostly on weekends.

Instead of a typical compact layout, this house was designed as a series of spaces with clear public and private zones. When seen from a nearby hill, it looks like a cluster of three houses rather than just a single one.

Satya Health Resort

Vanjarwadi, Karjat [1999-2001]

Entrance aangan to a cottageNestled in a valley between the Matheran and Bhimashankar ranges, on a 50 acre (20 Hectares) piece of land, this is a resort with a difference. It was designed to have the look and feel of a typical Indian village.

The layout reflects the variable contours, with groups of ground-hugging cottages following the gradients. Some units are arranged in a cluster around a central courtyard, while others have individual aangans from which one enters them. Including the unpaved, covered, otlas behind them, each room has almost as much outdoor space as it does within.

Handloom Training Centre

Maheshwar, MP [1994-1996]

Entrance to Kaya KalpBuilt in the historical fort of Maheshwar — old capital of the Holkar kingdom is this training centre for handloom weavers. It was built using only locally available materials and labour, which brought the cost of construction down to a surprising Rs. 1,125/m² (about Rs. 105/square foot). Today that figure sounds almost unreal but, even at that time, it had worked out to approximately one-third of what a similar, concurrent project in the same town had cost.

The walls were made entirely of load-bearing brick with no reinforced concrete whatsoever, and the mortar used was a mixture of lime and cement.