Delhi, with a population of over 11 million inhabitants, is plagued by a host of water related problems that are challenging any efforts on the part of planners to alleviate the burdens of urban lifestyles.

Also, zealous development efforts are offering high density residential neighbourhoods that are flaunting the basic open space norms.

This research is an attempt to optimally utilise the land available along the natural drainage channels and thence ensure that these channels remain unpolluted and maintained.

The Storm Water Network of Delhi comprises of a hierarchy of drains- internal drains that collect the runoff at the residential layout level; these then find their way into peripheral drains and further discharge into main trunk drains. The discharge from peripheral drains may find its way into a larger main/ trunk drain or directly into the River Yamuna.

Though this is the system conventionally designed to carry storm water but as a result of an inadequate sewage disposal system, a large quantity of untreated sewage finds its way into these storm water drains and thence ultimately into the river. This not only renders the water in these drains unfit for use but also results in polluting the river. 70% of the pollution in the river is caused by dumping of sewage that is transported from the households to the river via these channels reducing them to the role of urban sewers in the absence of an adequate sewage collection and disposal system in large parts of the city.

The city of Delhi that constitutes only 2% of the entire catchment area of the River Yamuna is responsible for 80% of its pollution load. All along its journey through the city, 1800 million litres of untreated domestic sewage along with 300 million litres of industrial waste find their way into the river predominantly through the 17 erstwhile stormwater drains that now play the role of Ganda Nallahs or dirty drains. As a result, what remains of the riparian biome is the "Green Soup"- a mix of Metals like Zinc, Nickel, Iron and heavy metals like Chromium and Cadmium; Fertilisers and pesticides like DDT, Aldrin, dieldrin-all much above the WHO set safety guidelines for river water to be potable; Chlorides and Suspended solids; Industrial and domestic waste containing mineral and organic nutrients that come from soap and food remains; Sewage containing coliform bacteria at levels as high as 1,80,000 MPN (Most Probable Number)/100ml. The 22 km. Long stretch of the river passing through the city results in a eutrophicated stretch that last for 490 kms (more than 20 times that length) before other tributaries dilute the pollution content. As a result of over extraction and pollution of underground water, the acquifers too have ceased to play the role of the dependable source of uninterrupted water supply that they were believed to be. The water table is observed to have been reduced by 19-22 meters in the span of just a decade (in the early 90’s).

The storm water drainage system in Delhi may physiographically be defined broadly as comprising of six drainage basins:

Flows through heavily industrialised areas along its 47 kms. stretch to the River Yamuna. It has a catchment area of 10939 sq.kms. and is responsible for discharging 1.028 million cubic meters of untreated sewage per day (source: 1982-86 statistics of the Central Pollution Control Board)

• Barapullah Nallah

With a width of 70 m. on an average this drain covers an area of 9.60 Ha. This drain collects the discharges of other internal, peripheral and trunk drains to further discharge its contents-1,25,000 Kld of domestic sewage into the Yamuna.

Draining the Southeastern part of the city

This drains the eastern part of the river. It drains an n urban catchment area of 7688 Ha. and a rural area of 7154 Ha.

Drains the North west part of the city

With the Supreme Court of our country passing a jurisdiction whereby adequate measures need to be undertaken to "clean up " the river-the governing authorities and their development agencies have been awakened to action oriented goals. They are after all these decades attempting a role reversal for the river –selling the cleaner greener river" to the people.

The government constituted a task force dated 30.07.93 to investigate and study a proposal for covering of the drains, especially those that are a "serious nuisance, have led to unhygienic and have squatter settlements on their banks". The study drew the following conclusions

• Internal drains may generally be designed to flow as open drains
• Peripheral drains were recommended to be designed as covered drains
• The main/ trunk drains were to be designed as open drains with fencing or boundary wall to be provided to discourage squatting and physical access to the drains.

The governing body responsible for development of a zone is further responsible for the drainage system.

The governing of Delhi is in the hands of three different bodies- Delhi Development Authority (DDA), Municipal Corporation of Delhi (MCD), New Delhi Municipal Committee (NDMC) and the Cantonment Board. The responsibility of the drainage system at the Master Plan and Zonal Plan levels rests with the Delhi Development Authority (DDA). But DDA does not involve itself in the areas under the jurisdiction of the other governing bodies thus the Municipal Corporation of Delhi (MCD), the New Delhi Municipal Committee (NDMC) and the Cantonment Board are responsible for the drainage systems within the areas under their jurisdiction. The Irrigation and Flood Control Department of Delhi is responsible for Planning and executing the main drains whose drainage capacity is more than 28 cumecs (1000 cusecs).

It seems rather incongruous that a situation such as this has arisen in a nation where water is generally revered by all the religions in some form or the other. Specifically, in the Hindu mythology each river flowing through the country has a special place in the religious iconography-the Yamuna being no exception. But if this held true, that this river and other Indian rivers have been revered as goddesses and nevertheless finds themselves in such a deplorable situation serves as quite an enigma. If this river was truly worshipped and its ghats (riverside terraces for religious ablutions) visited often enough (for activities other than for cremating the dead and immersing their ashes) then their story may have taken a different turn.

The stormwater drains played an important role in traditional water supply systems of Delhi by draining excess rainwater runoff and recharging wells, stepwell, tanks along the way. Being highly polluted themselves, these drains have rendered the secondary sources of water supply useless.

Due to the negative imageability of the drains as well as its reiteration in the form of boundary walls, garbage heaps, a stench, most urban developments have turned away from them using them as backyards. Thus not only have the land values decreased considerably but also this has begun a vicious cycle of further degradation with squatter settlements emerging along the drains.

With the river in question the sewage treatment has become the subject of many a heated debate, especially in the absence of adequate sewage treatment plants. The practice of the untreated sewage finding its way into the waterways of the city is an issue of much concern.

The lack the present plight of the river is blamed on lack of foresight on the part of planners. The conflict between the lack of open space in the city vs. the potential continuous public space available along a polluted drain, if solved would not only provide opportunities for developing an open space system for the city but also be a move towards solving the water related problems.

While tree lined avenues, pathways, maidans (large scale open spaces for public activities), public parks, river front gardens, agricultural fields, private gardens all contribute towards a " Green City", the drains are natural features of the city’s landscape which spatially link the various parts of the city sensitive towards it thus being a valuable resource for developing an open space system for the city. Besides this, a few of the other desirable characteristics of the drainage system that offer the potential of developing an open space system along it may be as elucidated below:

• The natural drainage system provides linearity/ linkage/ continuity in the spaces

• Some stretches along the less polluted drains have the potential to be developed as open greens and recreational spaces with minimum intervention

• Availability of water (though the quality may be questionable at present)

• Offers opportunities to work towards solving the drainage, sewage and ground water recharge related issues of the city in an eco-friendly and cost effective manner

• Offers means of improving the visual, physical, socio- cultural environment of the city

To illustrate these objectives, a stretch of one of the drains was selected for study. The Barapulla Nallah has one of the largest catchment population and area with many tributaries meeting it along the way. It is relatively cleaner as compared to the other drains as the residential areas it flows through are high –medium income housing with adequate sewage networks. It does not carry industrial effluents by virtue of not flowing through formal/informal industrial areas and contains water mainly in the monsoon months.

The particular stretch that was selected for the study of the drainage dynamics of the Barapullah drain was one that has a historic background of functioning as a reservoir the remains of which are signified by the "Satpula" (bridge with 7 spans). Also its proximity to the historic urban village of "Khirkee", educational institutions, residential colonies (mix of high income-low density to medium income-high density), proposed location of a District Level commercial and institutional, facility lend this area a dynamic identity.

Proximity to historic settlements enhance the potential of developing the site for conservation related tourism facilities. Located, as it is, between the famous settlements of Mehrauli and Tughlakabad this area may be envisioned as part of a comprehensive conservation scheme.

Surrounded by residential settlements, educational institutions, this area has scope to be developed for recreational purposes with nature trails and other activities being incorporated.

An appropriate site (due to availability of land) to set up a water cleansing reservoir that would ensure that the rain enters the residential areas carrying clean water.

Located in close proximity to the Jahanpanah city forest this has potential to be extended into a continuous green lung.

This is an attempt to improve the image of the drainage channels and to restore them to their erstwhile role of the natural spines of the settlement as also a step towards solving the urban water related problems.