What We Do

Climate Responsive Architectural Design

Have you ever felt hot and sultry in your home or apartment, especially when there is a power-cut? Or when your AC is under repair? Have you ever wondered why most modern spaces, like large shopping malls, or office spaces, require a continuously running, energy guzzling AC system to keep them usable / inhabitable? Or have you wondered how comfortable it was inside that magnificent old temple / monument you visited on your last family holiday? Or how comfortable it was inside the 150 year old ancestral home of your friends, without any AC, and sometimes even without a fan?

Most modern architecture has very little regard for the local climate. That is the reason why that modern building that you were so impressed by, could be located almost anywhere in the world – Sydney, Mumbai, Dubai, London, New York or Berlin.

On the otherhand, vernacular architecture from around the world looks so different because they have the highest regard for the local climate. This is why the igloo looks different from the homes of the masai tribes of kenya or the traditional chettinad homes of tamilnadu or the kath kuni homes in the himalayas. This is why their forms differ even when the structures are made of the same material, but in different parts of the world.

This does not mean that modern buildings, by definition, cannot cater to local climatic considerations. Its just that, by and large, architects have forgotten how to design for the local climate, thanks to all the convenience and changing aesthetical preferences that comes with modern industrial technology. The Late Ar.Laurie Baker designed and built a computer lab at the Center for Development Studies in Trivandrum, using exposed brick- work for a double wall and a filler slab roof, plenty of jalis with very few windows and with no use of ACs. A master-work in bio-climatic design.

Designing for the local climate, entails taking into design consideration the on-site temperature and humidity variations over time – days and years. It also entails orienting your building for appropriate heating, lighting and ventilation; choosing appropriate building materials that may help in regulating the flow of heat and moisture through the fabric of the building, so as to achieve good thermal comfort; and designing your openings and overhangs for desired levels of movement of light and air.

By and large, local materials, help in achieving good thermal comfort and in dealing with the local on-site climatic variations year round. Eg, the tiled / thatched roofs one sees everywhere in kerala, are adept in dealing with the heavy monsoons. And the slate roofs of the upper himalayan regions help in dealing with the rains and snowfall of the region, while also acting as a heat store.

We take the local climatic facrtors into consideration and design for it. It is one of the primary factors that influence our designs. We make use of softwares such as 3D Sun Path, Climate Conultant and Opague to help us in our design process.

Low-carbon Materials & Cost-effective Construction

It is pretty common for almost all to-be home owners to be concerned about the cost of construction and sometimes also about the environmental impact of their constructions. Steel, cement, glass, burnt-bricks, river sand, or any material that is transported from far off, are usually quite expensive and energy intensive, and sometimes, as in the case of river sand, have a high environmental impact, even though it is not an industrially processed material.

It therefore becomes imperative to reduce, to the maximum extent possible, the use of such energy intensive, industrially processed materials, and instead make use of low carbon, local materials like mud, bamboo, natural grasses and reeds, etc, where possible and optimize on the use of steel, cement, glass, burnt-bricks, sand, etc, by using optimizing construction technologies, such as rat-trap bonding in masonry (that reduces the brick requirement by 25% compared to regular english bond), or filler slab roofs that optimize on the use of concrete (cement, steel & sand) compared to regular RCC roofs, or exposed brick-work masonry – without a coat of plaster – to optimize on the amount of river sand, in cases where replacing materials with low-carbon alternatives is not entirely viable.

Low-carbon, local materials like mud, bamboo, etc are generally quite affordable and available on or very near to site. While one would require a basic ‘feel’ or understanding of the material to be able to work with the material, its not rocket science to get to understand the materials and learn techniques of using them. And while the indigenous knowledge of working with such natural materials is getting lost with every passing year, there are still numerous workshops being conducted year round, all over India and elsewhere, where one can learn to build with natural materials.

Building with natural materials, especially when one has the know-how and can DIY, or when one can get some guidance as and when required, or with the help of some local traditional expertise, can be one of the most affordable and fun ways to build a house. Homes built with natural materials are commonly perceived as maintenance intensive, compared to their conventional, modern counterparts. The truth is that they require a fairly simple, but regular maintenance schedule.

Cost-effective / optimizing construction techniques

In cases where working with low-carbon natural materials is not entirely viable, it is possible to optimize on the use of steel, cement, glass, burnt-bricks, sand, etc, by using optimizing construction technologies, such as rat-trap bonding in masonry (that reduces the brick requirement by 25% compared to regular english bond); filler slab roofs that optimize on the use of concrete (cement, steel & sand) compared to regular RCC roofs; arches instead of lintels or beams for openings; or exposed brick-work masonry – without a coat of plaster – to optimize on the amount of river sand; etc.

Laurie Baker termed these as cost-effective construction techniques and distinguished them from low-cost construction techniques, as in these techniques may lead to some cost-savings in some cases, but more than savings to the home owner, they definitely ensure a different and more equitable and sustainable distribution of expenses – on local labour more than on industrial materials, which also helps in sustaining local skills and livelihoods.

Rat-trap bond: This is an alternative brick bonding that was introduced and extensively used by Ar.Laurie Baker in all his works in Kerala. It uses brick-on edge and comprises of two-paralled ‘facers’ with a 3” cavity between them, followed by a brick-on-edge placed at 90° to lock the bond, as can be seen in the image below. Because all the bricks are placed on-edge the height of each course is 4.5”, instead of the usual 3” as in the case of English or Flemish bonds. This effectively means that with rat-trap bond, you will require about 25% less bricks to complete a brick wall of the same 10” height, as compared to a conventional English / Flemish bond wall. Rat-trap bonding, irrespective of a plastering layer on its surface, allows for concealed electrical conduits through the cavities in the wall, without any chipping of the wall structure.

RCC Filler-slab roof: Concrete is good in taking compressive loads, while steel is good in taking tensile loads. In a typical Reinforced Cement Concrete (RCC) roof slab, the tensile loads form in the bottom half of the slab, and compressive loads form in the top half of the slab, especially in the middle of the rooms, away from the walls. The tensile and compressive loads get inverted above the walls, when there is a support from below – there is compressive load at the bottom of the slab and tensile load at the top of the slab.

This is why reinforcement is used in the bottom-half of the slab, in the middle of rooms, away from the supporting walls, whicle the same reinforcements are cranked to stay in top-half of the slab above the walls.

As there are totally negligible compressive loads in the bottom-half of the RCC slab, away from the walls, concrete has very little role to play in the bottom-half of the slab in such situations. Concrete can therefore be replaced to a large extent in the bottom-half of the slab, by a wide range of filler materials, such as mangalore tiles, shallow terracota pots, coconut shells or even electronic waste of appropriate sizes.

Such filler materials do not affect the structural strength of the slab in any way, as they are replacing concrete only in areas of the slab where concrete has anyway no role to play. But they do help in optimizing on the amount of concrete used in such a roof slab and help in reducing the dead weight of the slab and thereby raising the potential for optimizing the design of the foundation for lesser dead loads, leading to more savings.

The bottom of a filler slab roof may be left exposed, such that the arrangement of the filler materials is visible or it may be completely plastered like a regular slab. While a plastered and painted slab soffit allows for more diffused ambient light inside the space, the aesthetic considerations are entirely subjective.

Arches for openings: In conventional construction, it is common to span openings (doors, windows) with continuous or bit lintels and wider openings with beams, which use a fair amount of concrete (cement and sand) and steel. It is fairly straighforward to replace the concrete lintels and beams with brick arches (including flat arches) with or without concealed lintels. One can significantly optimize on the amount of concrete used for structural purposes, without compromising on the structural integrity of the structure, while increasing the aesthetics of the structure through the use of arches.

Exposed brick-work masonry: The plaster layer over a brick masonry wall, serves way more an aesthetic purpose than a structural purpose. A plastered wall, can be painted to any colour of ones liking, while it doesn’t add anything to the load bearing capacity of the wall. In the same way, an unplastered wall, gives an entirely different kind of aesthetics – rich colour and texture of a brick wall – while it doesn’t take away anything from the load bearing capacity of the wall. But it does significantly optimize on the amount of river-sand (or M-sand) used in construction and can be left un-painted for a richly coloured & textured aesthetic or simply only white-washed for more ambient lighting with a textured finish.

Other optimizing construction techniques: Use of stone-slabs in brick-masonry walls for ‘built-in’ shelves is a great way to optimize on the use of wood for shelving. Simply supported concrete or ferrocement slabs on brick-masonry, where possible, instead of an entirely concrete staircase slab, can help optimise on the amount of concrete. Having built-in furniture our of brick masonry – seating, beds, etc – can help in optimizing on the use of wood for furnitures. Making use of brick jalis instead of windows is a great way to optimize on the cost of windows, while providing fantastic diffused light and good ventilation.Using reclaimed wood, bricks, stone slabs, etc is a great way of re-using materials that would otherwise go to waste and also of optimizing on the construction costs.

Comprehensive Sustainable Water Management (CSWM)

Access to water resources is the single most important factor in deciding on a place to live, be it when considering to buy a new home / plot of land, renting a new home or even continuing to live in the same place. Ground water sources, especially the deep aquifers, have been unabatedly exploited for years on end with no regulation on borewells, that it has become a highly stressed resource in almost all urban areas, and also increasingly so in rural areas.

A major component of CSWM is water budgeting – how much water can we potentially harvest from rains? What will be the per-capita water consumption over time? How much waste water can we treat and recycle / re-use and for what purposes? Can we rely solely on rains and open wells (renewable water resources) for our water consumption needs without resorting to bore-wells for accessing fossil water? You may view a sample water budgeting sheet below, that we prepared for a client in Madurai, who intended to rely solely on rain water & municipal supply for their water requirements.

We design efficient rain/surface water harvesting systems for storage (in tanks) and/or for ground water recharge (through open wells). And we help design and put in place a low consumption system, so that water wastage is not dependent on the end user. And we also design DEcentralised WAste-Water Treatment Systems (DEWATS) for treating waste water for recycling or re-use.

Ecological Sanitation

The Probelm with the present sanitation model: Has it ever struck you how much fresh clean water we use to flush our solids down the WC? And have you ever wondered where it all goes or what happens thereafter once you flush it? The modern sanitation system, characterised by the “flush and forget” system, is barely a few hundred years old – Sir John Harrington’s flush toilet was invented in 1596. For millenia before that humans have been, by and large, defecating in the open, the same as all other life forms on this earth. In the early stages of development of a “sanitation system”, it was still very much a communal

The problem of waste:

Assuming betwen 3 to 5 flushes per person per day and 6 to 10 liters per flush, an average household of 4 persons having access to flush toilets, wastes anywhere between 26 thousand to 73 thousand liters of clean fresh water, per year, only for flushing. It will take anywhere between 6 to 16 months to fill up an average sized 10ft x 12 ft (x 10ft ht) bedroom with this amount of waste.

Scaling it up, the city of Mumbai, with a population of 20 million, will produce anywhere between 360 million to 1 billion liters of waste water per day only through flushing. Enough to fill between 144 to 400 olympic sized swimming pools per day. Scale it further up over a year and we are looking at 52 thousand to 146 thousand olympic sized swimming pools of sewage from flushing alone.

And guess what? The very first stage of treatment in a septic tank or a sewage/waste water treatment plant, (if at all our toilet waste reaches one instead of flowing into the nearest water body) is ‘primary sedimentation’ – separation of the solid and liquid wastes. All this after the solid and liquid “wastes” exit our bodies through separate channels!

The probelm of health:

Our faecal matter contains millions of bacteria and pathogens from our intestines. They thrive in moist and wet conditions with little to no oxygen. Flushing them into septic tanks or underground sewage networks with plenty of water gives them a long life extension.

All sewage networks in India empty into surface water bodies, mostly rivers, either directly (which is very common) or via STPs (less common). In the largest study of its kind, Michigan State University researchers sampled 64 rivers in Michigan for human fecal bacteria. Their conclusion, in 2015, destroys the notion that septic tanks prevent fecal bacteria from seeping into rivers and lakes.

And contamination of water bodies with faecal bacteria and pathogens is the leading cause of water borne diseases such as cholera, diarrhoea, gastroenteritis and typhoid. Diarrhea accounts for about 1.73 million deaths worldwide each year and 90 per cent are children under 5 years, mostly in developing countries. 88% of cases of diarrhea disease world wide are attributed to unsafe water and poor hygiene. Inadequate sanitation is said to have caused India considerable economic losses, equivalent to 6.4 percent of India’s GDP in 2006, or Rs 2.4 lakh crore.

The Nutrient cycle – Human dung” or “Humanure” as a resource? Humans have been using their excreta in agriculture since millenia.

It is still very common in rural India and many parts of asia, for people to ‘go to the fields’ to answer nature’s call. Collecting human dung from urban “producers”, for use in agriculture, was an important, respectable & even a booming business in China & Japan.

A Quing Dynasty Emperor, in 1737 China, issued a decree titled: ‘Treasure Night Soil As If It Were Gold’, prescribing all his subjects to diligently gather their excrement and put it to good use, as it was being done in Jiangnan Province in Southern China, where collecting night soil was a booming business. The Emperor’s main reason for issueing the decree was the streets of Jiangnan Province were way cleaner than in his own province. (Worster, D., 2017)

In Japan, it was common for humanure to be collected from urban “producers” of Osaka & Tokyo and sold to the farmers in the neighbouring villages. Its value was measured in gold and it was in such high demand that governing bodies had to outline a strict system of its rights and regulations. For example, if a family rented a house, who had the rights to the excrement – the tenants or the landlord?

It was also not uncommon for farmers to fight over over their priviliges for collecting night soil, as did happen in the summer of 1724, when two groups of villages embattled in ‘poop wars’, over their collecting rights from different parts of Osaka. This led to the urbanites forming their own organisations that oversaw night soil trading and price negotiations. They even raised the prices on their ‘precious poo’ (Hanley, S., 1987).

It was mainly after the industrial revolution and the invention of the modern WC, that we intentionally broke the nutrient cycle. This ofcourse led to a whole gammut of pollution problems, from both the fertilizer factories and from the excessive amount of sewage flowing into water bodies.

So, what made/makes humanure so valuable? What does humanure consist of?

Our poop primarily consists of 75% water. The remaining 25% are mostly valuable resources as can be deduced from the above table. It was estimated that in the year 2000, about 45 million metric tonnes worth of agro- nutrients (Nitrogen, Phosphorous and Potassium) was ‘recoverable’ from the total of (about) 3000 million metric tonnes of humanure ‘generated’ that year (Jenkins, 2005).

That amounts to about one third of total (approx 135 million tonnes) fertilizers consumed that year (FAO, 2003). The potential climate change impact of composted faeces as a low carbon (emissions) fertilizer substitute, in terms of reduced emissions can be huge.

It is clear from the tables that human excreta or humanure is way more a valuable resource, than a disgusting waste.
So, how can we go about harvesting our poop and using it as a resource?

By using Composting Toilets.

Most ecologically minded people may be familiar with composting their kitchen waste for their kitchen garden. Composting toilets take that process one step higher, and help us to compost our excrement. There are several types of composting toilets, but the basic premise of all is the same: the solid and the liquid excrements are separated at source, or as close to source as possible. The urine and wash water are diverted and can be safely used for plants and vegetables. The faecal material is allowed to decompose, in a dry environment, sometimes with the help of added carbonaceous materials, to form rich compost over time.

We have used both the urine-diverting-dry-compost-toilet (UDDCT) and the aquatron system in our projects. The UDDCT used a urine-diverting pan that helps separate the urine at source, while the faecal material falls directly into a bio-chamber. The user ofcourse has to shift slightly forward to wash-up after business, so that wash-water does not enter the bio-chamber, but gets diverted through the urine trough. It helps the composting process and reduces the offensive smell, if dry carbonaceous matter, like saw dust, dry leaves, or cooking ash, etc, is added to the top of the heap in the bio-chamber.

All UDDCTs come with dual bio-chambers, so that when the first chamber is full, it can be left alone to compost, while the second chamber is used, until that fills up too. The first chamber is emptied of the richly formed compost, only when the second chamber is also full. The chambers are sized according to number of users and the time required for composting. The only draw-back of this system, if at all, is that the user-interface is different from what we are used to, in that, the user needs to change position after the business, for the washing up. This is only a problem in India and in other cultures, where prople wash up their behinds instead of using toilet paper. (Image on left: A UDDCT installed on the first floor of a multi-story residence in Madurai)

Aquatron systems, is a composting toilet system developed in Sweden in 1986. It uses a simple separator, that works on gravity and centrifugal force, to separate the solids and the liquids. The bio-chambers can again be sized to requirements. Typically, one would require one aquatron system per residence. But this is also a scaleable system, in that, if one builds a masonry/concrete bio-chamber or two of appropriate size(s), one can have a single aquatron separator, cater to an entire apartment complex, or a commercial/office complex. (Video on the right shows the functioning of an aquatron separator. Source: P Bizproto)

The bio-chamber of a composting toilet will be able to hold, easily, anywhere between seven to eight times the volume of poop, in dry form, compared to a septic tank of the same size, given the same frequency of use. This is because, poop shrinks down to about one quater its volume, when it is allowed to dry out. Remember that fresh poop is about 75% water? And its also because copious amounts of precious clean water is not used for transporting our precious poop. Take the water out of the equation and allow for shrinkage, and you can store seven to eight times the volume of poop, in dry form, compared to a septic tank of the same size, given the same frequency of use.

References:

Zseni, Aniko. (2015). Human excreta management: human excreta as an important base
of sustainable agriculture. Available at:
https://www.researchgate.net/publication/273382957_Human_excreta_management_human_excreta_as_an_important_base_of_sustainable_agriculture

Jenkins, J.C., The Humanure Handbook: A Guide to Composting Human Manure, Joseph Jenkins, Inc., White River Junction, VT [Distributed by] Chelsea Green Pub., 2005.

Worster, Donald. 2017. The Good Muck: Toward an Excremental History of China. RCC
Perspectives, No.5., pp. 1-54. Available at:
https://www.jstor.org/stable/10.2307/26290680

Hanley, Susan.B. 1987. Urban Sanitation in Pre-Industrial Japan. The Journal of
Interdisciplinary History, Vol. 18, No. 1 (Summer, 1987), pp. 1-26. Available at:
http://www.jstor.org/stable/204726

Green Roofs & Natural Swimming Ponds

What is a green roof? What are the types of green roofs?

A green roof is a roof of a building, already existing or newly built, that is partially or completely covered with a growing medium over a waterproofing membrane for the purpose of growing different kinds of vegetation. It may also include additional layers such as a root barrier, drainage and irrigation systems. Green roofs are adaptable to any scale, starting from a small garage roof, to roofs of large industrial or commercial spaces.

There are mainly two kinds of green roofs. Intensive green roofs, are thicker, with a minimum depth of 12.8 cm, and can support a wider variety of plants but are heavier and require more maintenance. Extensive green roofs, are relatively more shallow, ranging in depth from 2 cm to 12.7 cm, lighter than intensive green roofs, and require minimal maintenance.

For private homeowners, an intensive green roof allows you to pick and choose which flowers or plants you would like represented, enabling you to sculpt the kind of aesthetic you desire. These are generally designed as a garden / formal space and are more inteded to be used by people. Extensive green roofs on the other hand are designed only to be entered for their yearly maintenance, so they become more naturally overgrown than their intensive counterpart. This makes extensive green roofs harder to navigate, meaning individuals can’t walk through the space to enjoy the flora.

What are the risks/costs and benefits of having a green roof? Why have a green roof?

Lets start with the risks and costs.

Structural Loads

An additional layer of growing medium (soil) on top of your roof, means additional load, especially with the amount of water such a medium can hold. Your roof should be designed to take this additional load. In case of existing buildings, the roof should be assessed for its load carrying capacity to determine if its safe to have a green roof on top of it.

Leakages

While all green roofs are designed to have a proper water proofing layer, proper drainage and even a root barrier, there may be some cases, due to varying reasons, where such root barriers are breached, leading to leakage issues and damage to structure. Such issues can usually be addressed by repairs and by changing the kind of vegetation if needed.

Costs

One of the main concerns when considering the installation of a green roof is the high initial costs. And depending on the type of green roof – intensive or extensive, the cost of maintenance may also vary – high for intensive roofs and low for extensive roofs. But in almost all cases, the benefits of having a green roof far outweigh the risks and costs of having one, especially in the long term.

That brings us to the benefits of green roofs, which are multi-fold, benefitting individual home owners, the wider local community and also the environment at large.

Thermal comfort and energy conservation

The layer of soil and vegetation on top of your roof, especially with the high moisture content in the soil acts as a massive thermal mass. This naturally improves the termal comfort inside the building and helps in reducing the cooling loads of the building during peak summer and the heating loads during peak winter. A cluster of green roofs in an urban area, have been shown to reduce the average temperature of the area, by combating the urban heat island effect.

Water conservation

The growing medium / soil on top of a green roof acts as sponge that absorbs plenty of water, especially during thunder-storms and slowly releases it. Individual home owners may benefit from the increased availability of rain water on-site, which may be used for storage and personal use or for ground-water recharge.

At a local or even at a city level, when a significant percentage of buildings have installed green-roofs, this high-absorption and slow-release significantly helps in the management of storm water run-off and greatly reduces the stress on local sewer systems and can helps to keep about 95% of the rain water on-site with very little run-off. Mumbai and many other urban areas, that regularly face flooding issues during monsoons, will hardly see any flooding if even 25 – 33% of the buildings in the city had green roofs installed on them.

Carbon-sequestration and improved air-quality

Plants are obviously known to sequester carbon and improve air-quality. The amount of carbon sequestration and air quality can be improved by changing plant species, increasing substrate depth, substrate composition, and management practices.

Increased Bio-diversity

Green roofs provide a habitat for wildlife including pollinators, birds and more and increases the local biodiversity. Detailed research in Switzerland and the United Kingdom has shown that ecologically designed extensive green roofs can provide good habitat for wildlife. However, there are limitations in terms of replicating habitat at ground level and thus should not be considered a substitute for the same.

Increases human well-being

There are many benefits to spending time in nature including increased cognitive function and decreased blood pressure, stress hormones and symptoms of anxiety and depression.

Increased Value for the Property

A study in Columbia, Canada observed that extensive green roofs could potentially increase the value/price of properties by between 2% and 5%. While, intensive green roofs increase may vary between 10% and 20%.

Green roofs will be a key element in dealing with flooding issues in urban areas in the coming future, especially with the unpredictable and increased frequency of high-rainfall instances.

Many cities like Berlin, Ontario and Chicago are pro-actively promoting the installation of green-roofs thanks to its multiple benefits. Even in places where the local authorities are not actively promoting the adoption and installation of green roofs, individual home owners, who realize the multiple benefits of green roofs are adopting them, especially in western parts of the world.

It can be safely said that green roofs are low-risk, short-term investments in terms of net returns and that the probability of profits out of this technology is much higher than the potential financial losses.

What is the history of Green Roofs? How can i be sure that this is not just the latest green fad?

The first green roof was developed long ago, with one of the earliest recorded instance being the Hanging Gardens of Babylon, one of the seven wonders of the ancient world, created in 500 B.C. At the time, the structure was built on stonework, using tar and reeds as the lower protective layers.

The modern method of building green roofs, however, was formed in Germany during the 1960s, creating the layering system that is implemented today. While fairly common in Europe, this practice is only now starting to gain popularity in the United States and in parts of Asia, including India.

Modern green roofs also differ from those made in ancient times because the technology has greatly advanced. The layers utilized to create today’s iterations include soils, three different fabrics, and drainage plates and mats. The drainage systems also make these stand out from previous versions, utilizing the soils’ natural tendencies to guide the water in ways that help better maintain the system.

Scientists and engineers are still researching the best methods for green roofing. This is primarily focusing on how green roofs might be built in different climates and environments, as well as the scale in which these can be made.

Natural Swimming Pools

When was the last time you had a swim in a lake or in your village pond / well? How was it different from your swim in the swimming pool? Chances are that your swim in the lake or village pond was probably way more fun, even though your local swimming pool water was way more clean (and clorinated). In all likelihood its the natural setting of the lake / pond that makes all the difference.

What is an Organic /Natural Swimming pool?

It is a constructed swimming pool, not with concrete and ceramic tiles, but with natural materials and perhaps a water-proof lining, such that it is part of a vibrant and diverse natural eco-system of plants, reeds, insects, fish, and numerous micro-organisms that constantly filter the water and keep it clean without the use of chlorine or other disinfectants. So the water doesn’t bleach your skin, sting your eyes, or corrode your teeth.

Why have a natural swimming pool?

Everyone loves a good swim (that’s the rule, which may ofcourse have exceptions!), but not everyone can afford to have a swimming pool as part of your home or farmhouse. Natural swimming pools can be constructed at a fraction of the cost of conventional swimming pools and are aesthetically way more pleasing than their conventional counter parts and are beneficial to the eco-system where it is located and to bio-diversity at large!

How do natural swimming pools work? What kind of maintenance does it involve?

The plants, insects, animals, reeds and micr-organisms that are naturally found in water bodies are good at filtering the water and keeping it clean.

The key to promoting a diverse eco-system is to prevent one species from dominating the pond. In a poorly created pond the usual dominating big baddy is blanket-weed. Blanket- weed (Cladophora superphylum) is the commonest filamentous alga forming dense swathes over ponds in bright warm weather where phosphate and nitrate levels are high.

However, it is important to understand that algae, will never disappear completely, after all they are wild plants and part of the healthy eco-system. But in a properly functioning pool most of the algae will be confined to the margins or hardly be visible at all.

So, if you are thinking of having a swimming pool as part of your farm-house or building one for your local community, you may want to consider building an organic swimming pool!