Constructing in deserts and dry lands: Are we green?
I am often intrigued by promotional campaigns of several upcoming developments being advertised as green buildings, the common claims being “Green podium landscape”, “rain water harvesting”, “solar powered outdoor lights” to support the statement. It would be interesting to note that lush green lawns take about 4 times more water to maintain itself than landscape with native species and trees; rain water harvesting may not be feasible for all locations and outdoor lights contribute to miniscule energy consumption in comparison to energy consumed in buildings and hence use of solar powered outdoor lights may hardly bring down energy consumption of a large complex of buildings. Incorporation of green concepts should be done with a holistic approach and yield tangible benefits to consumers and environment. Let us dwell a bit more on the issue of water.
For example, rain water harvesting, unless done properly may have serious consequence on ground water quality. Care should be taken to ensure that proper filtration and screening is done prior to recharge of rain water into ground. Roof top run-off is usually stored or recharged. Runoff from pavements, roads, unless pre-filtered appropriately, may lead to ground water contamination. Rain water harvesting may not be feasible for ground with high water table, in rocky terrains and needs careful soil investigation before it is designed . While rain water harvesting is an important measure to counter depleting water tables, the key question arises on how far are upcoming developments viable as far as water availability is concerned.
The per capita water availability in India is decreasing over years and has gone down by 15% from 1816cum/capita in 2001 to 1544 cum/ capita in 2011. Developments such as Gurgaon is facing the brunt of the problem with water table as low as 200 feet in places (although rain water harvesting is a mandate in Gurgaon) . Availability of water varies regionally and incremental urbanization without matching plan to meet increasing water demand can leave several developments high and dry.
I was on a recent visit to an upcoming green campus in the outskirts of Jaipur. Traversing quite a few kms across the dry and arid terrain ,the first glimpses of the upcoming facility for 16, 000 students , aspiring to avail world class facilities in engineering, medical and allied disciplines holds promise as a dream destination. The facility is being designed to meet highest green building standards. However there is no assured water supply from local authority. The campus is entirely dependent on ground water for its potable water supply. The construction water is purchased in tankers.
Being committed to ensure sustainable water supply and management, the campus is designed as a zero discharge campus. This is particularly crucial as the water table in Jaipur varies between 10m to 70m and is depleting @ 0.5 to 1.6 m annually. The landscape design of the campus integrates effective water management strategies. A series of pebble lined swales capture every drop of rain that falls on the site. The swales allow percolation of rainwater into ground water. Excess water filters into a series of storage tanks. The storage tanks also capture roof top rainwater. Planting of the low water consuming plant species, low flow fixtures in toilets and water efficient air-conditioning ensures low water demand. To reduce demand of purchased water during construction, admixtures are used in concrete. The entire waste water is being treated and reused for landscaping and flushing. Yet, the future is uncertain. No one knows if the borewells shall dry up one day!Environmental sustainability is currently delinked from urban policy and planning processes.
It is a fact that most of our urban centres are not planned developments. Currently master plans are available for about 1500 towns out of 5161 urban centres in the country, and implementation is a serious challenge. City development plans have been key as far as project and infrastructure investment planning for the JNNURM cities are concerned. But there is little harmonization between master plan, regional plans and CDPs. Complimenting above challenges, outdated UDPFI guidelines and CPHEEO manuals have weakened the urban development policy framework and resulting in unbinding of rules of developments. Revision of existing planning laws, norms and space standards and formulation of urban environmental policy is crucial to ensure that our future developments are sustainable. Convergence of different plans needs to be ensured through better coordination among concerned authorities.
In view of the status of urban water supply and sewage treatment and with respect to gap in delivery of basic service such as sustained water supply for future developments, the following strategies should be in place:
City water resources planning and management plan should include sustainability of surface water and protection of groundwater recharge areas.
The land use plan should consider existing water sheds, catchment areas, and it should be ensured that existing catchment areas are not impaired by faulty landuse planning.
Cities should be encouraged to plan for own sources to reduce cost of water supply.
Local water sources should be managed sustainably and equitable distribution should be ensured.
Use of treated waste water and rain water should be advocated.
Importance of water conservation and minimization of water demand for various applications should be promoted through active campaign.
Water utilities should plan for full cost recovery of water treatment, management, operation and maintenance.
Tapering of subsidies can ensure sustainable water use.Over consumption of water should attract higher tariffs.
Good practices such as rain water harvesting and recharge of aquifers, water audit and efficiency enhancement of recycle of waste water and its reuse, and complete access to sewage and sanitation system on-site or off site should be inplace.
Success of future developments is embedded in in their long term sustainability and an integrated and holistic approach to sustainable water management is essential.
source- The Economic Times