TOWARDS A WATER POLICY FOR AUROVILLE & TOWN PLANNING ISSUES: DECISIONS TO TAKE NOW

It is time to make choices ! Multi sourcing? Storm water as a core resource? Matrimandir Lake as major part of the water system? Integration in planning and development issues?

Outline of our water policy 1.The water in Auroville so far 2.Can we continue to develop along the same lines? 3.What are the alternatives? 4. Recommendations (a draft Water Policy)

Since the beginning, water supply in Auroville has been developed exclusively on groundwater today, the overall supply is satisfactory quality wise and quantity wise we have significant assets in the form of water harvesting, wells and have good knowledge of the system 1. The water in Auroville so far - 1/2

but... –we use only one resource: ground water –water infrastructure is mainly local, at community level, which prohibits the pooling of resources in case of local shortage of supply 1. The water in Auroville so far - 2/2

2 - Can we continue to develop along the same lines? - 1/3 NO! For several reasons... Water needs will increase with the population growth: factor 10 in years the only “rechargeable” aquifer is Cuddalore... –which is leaking into further down aquifers –is overexploited regionally –is already intruded by seawater along the coast

therefore Cuddalore cannot meet our needs, we must rely on the regional system, as it is already done today but, at regional scale, Auroville “weight” no more than 1% on the aquifer system. moreover, regional extraction amount to 4 times the recharge Can we continue to develop along the same lines? - 2/3

our best efforts can not counteract the regional agricultural practices: more than 200Mm3/yr extracted compared to our need = ~1Mm3/yr main aquifer, Vanur, has lost more than 50m in 25 years and is below sea level, seawater intrusion may occurs at any time, which would totally ruin the regional resource 2 - Can we continue to develop along the same lines? – 3/3

3. What are the alternatives? - 1/2 desalination: –cannot be generalized because it is too costly and energy-intensive –hence only an additional resource, a safety factor –if implemented, it is easier and cheaper to desalinate groundwater instead of seawater wastewater recycling –represents only a fraction of needs –should certainly be a part of our span of resources, aimed at non "hygienic" purposes, would reduce the demand for "clean" water

harvesting and treatment of storm water –urbanization will make this resource more relevant: less recharge, more runoff... –rain is abundant (6Mm3/yr on city’s area) but unevenly distributed during the year, collecting and storing this water means developing a large capacity system –Matrimandir Lake could fit in such a system and play a key role for Auroville; as opposed to groundwater, can be controlled by Auroville –Once collected and stored, the treatment of storm water is simple 3. What are the alternatives? - 2/2

 to build a multi-sourcing supply system to set up a system for sharing these resources to develop a distribution system that would facilitate the development of the city to organise our capacity of monitoring, allowing the control and adjustment of our Policy to control our own consumption work in the long term with our partners, at regional scale (less extraction, more groundwater recharge) 4. Recommendations (a draft Water Policy)

groundwater, extend ground water recharge at our scale  storm water, with an extended harvesting and treatment system, possibly based on the Matrimandir lake => PLANNING! to develop advanced recycling practices to prepare ourselves for desalination... What could be a multi-sourcing system?

Storm water management, a key issue for town planning! Town planning Urban layout Storm water management Infrastructure Drainage & storage system (incl. lake) Water system

We need to make choices NOW! And at first to start a study group on storm water management and Matrimandir lake in relation to Town planning