Integrating nature based solutions: Green, Blue and Grey Infrastructure

Climate change is not a new phenomenon our earth is experiencing. The very reason we are here today is due to climate change: extinction of Dinosaurs and subsidence of Ice Age. Climate change is a continuous natural process and cannot be stopped, but then why it is affecting us today like never before? The reasons may be reduced human adaptability to climate change due to change in living conditions, haphazard urbanization leading to concentration of climate related challenges in our cities and non-resilient nature of our cities to respond to disasters.

With the advent of 3rd industrial revolution, urban landscape of the world changed. Land became a commodity rather than a precious resource which was to be used carefully. People started extensive construction on whichever land they found potential in regardless of its natural use or presence of natural features on or beneath the ground. With vertical growth one also needs to dig deep for foundation. This led to blockage or diversion of natural drainage channels, less permeability due to concretization of surface, removal of mangroves, natural forests, shrubs, encroachments on drainage lines due to lack of building control regulations and levelling of land surface led to disturbing the natural slope thus impacting flow of storm water. A resulting impact of these man-made blunders has reduced our resilient capacity to disasters, increased risks of human loss and exposed our economic engines (cities) to greater loss than the same disaster would cause in rural areas.

Green Infrastructure is strategically planned and managed networks of natural lands, working landscapes and other open spaces that conserve ecosystem values and functions and provide associated benefits to human populations. The foundation of green infrastructure networks are their natural elements – woodlands, wetlands, rivers, grasslands – that work together as a whole to sustain ecological values and functions. Healthy functioning natural or restored ecological systems are essential to ensure the availability of the network’s ecological services. ( They can be categorized as Parks and gardens; amenity green space; natural green spaces and green corridors.

Grey infrastructure refers to buildings, roads, and other urban constructions. Blue infrastructure refers to water elements, like rivers, canals, ponds, wetlands, floodplains, water treatment facilities, etc. ( These 3 form an important part of our urban ecosystem and should be equally looked upon but we tend to focus more on grey infra like constructing tall buildings, wide roads or new industries. Blue and green infra are often neglected for the cause of new “modern” construction and this has led to deterioration of our natural environment, pollution of water resources, manifold deforestation and encroachments in floodplains, wetlands etc. Adaptation and implementation of Integrated Green-Grey-Blue Infrastructure Development Framework is an opportunity for us to improve quality of urban life.

Water bodies (Rivers, lakes, streams, canals) are an important part of our water security programme and booster to our engine of growth. They need to be preserved and maintained at the best standards for comfortable living. If planned properly, these water bodies along with green infrastructure can be a place for leisure, tourism and bio-diversity in the hustle and pace of urban living. Latest technologies like Geographical Information Systems (GIS), remote sensing and satellite data can be effectively used to implement and maintain infrastructure in urban areas. High resolution Digital Elevation Models (DEM) can be generated to delineate watershed areas and collection points of drains. Also, with effective monitoring, encroachments can be prevented in natural flow of water. GIS can be used to plan the drainage network for the city with minimal cost and maximum effectiveness considering the natural slope, orientation, geography of the area. Sewer drains should not be allowed to directly connect with a river or lake, instead all drains should be interconnected and be carried to a sewage treatment plant and after treatment should be reused in watering of gardens, parks, in flushing of public toilets, washing of roads etc. and then any excess water be released into water bodies. According to the new unified DCPR for Maharashtra, 15% plot area has to be left for amenities and open spaces while building apartments or townships. Water used in here can be recycled and reused in these open spaces. This way the construction can also achieve zero net discharge tag.

Storm water drain network should run parallel to all roads of the city and be made of material which would allow water to percolate in the ground. All roads should have a slope from the median to the shoulders to make run-off easy. Low-lying areas or flood prone areas can be identified through GIS and can be converted into open public spaces serving dual purposes of recreation and flood mitigation. Household rainwater harvesting system should be made a compulsion which would reduce the strain on the storm drain network. Also, community level rainwater harvesting can be done on gardens, parks, medians of roads to avoid flash floods and at the same time increase water storage capacity. Pavements should be made of permeable material so as to allow natural recharge of groundwater. Rooftop parks and gardens can reduce the surface runoff and help in flood management.

Buffer of 50m on both sides of river outside municipal boundary and 20m within municipal boundary should be declared as bio-diversity zone. Horticulture and orchards should be planted outside the municipal limit and riverfront development, cycle track, roads, gardens, parks, open-air theatre, open-air library etc can be built in the 20m buffer zone within municipal limits. The pilot project to revitalize the Waghari River of Yavatmal District was based on this theme. Dense afforestation on both banks prevented top soil erosion, held water thus preventing flooding, acted as oxygen powerhouses for the surrounding area, supported growth of natural flaura and fauna, created a habitat for wildlife to flourish and most important of them helped make the river perennial. For areas within municipal limits, the 20m buffer can be utilized to create world-class open and recreational spaces. Riverfronts and lakefronts, botanical gardens, butterfly parks, drive-in theatre, amphitheater, sky observatories, exhibition spaces, cycle tracks, yoga centers etc. can be developed in this zone. Only soft scaping be done and maximum area should be covered through plantations. Essential construction should be done through locally available construction material only and use of concrete should be prevented. The concept of sponge cities can very well be implemented in these areas. The Sabarmati riverfront and the Kakadia Talav of Ahmedabad are excellent examples of integrating green-blue infrastructure in urban India. Another example by a community organization has been Mission Sujalam Sufalam, wherin they desilted, deepened and widened all the major water bodies, tanks, streams and canals of Buldhana district. The silt, rich in minerals and very fertile was excavated, transported and supplied for free to farmers of the region, who spread and mixed it with the topsoil of their farms thus increasing fertility and productivity of the land. This mission helped in mitigating drought conditions by increasing water storage capacity, reducing run-off and increasing the bearing capacity of soils as well as the water table. This model was accepted by NITI Aayog and further moderated to include development of mini-forests, afforestation and green spaces around major lakes and tanks of the district.

Community and self-help groups should come forward and take responsibility for the maintenance of neighborhood parks, city gardens and other open spaces in the city. Also, rooftops can be better utilized for terrace farming or for gardening. Medians of roads and shoulders of pavements can be dotted with plantations of native trees. All this would help in reducing the urban heat island effect and also lessen the strain on our already weak storm and sewer infrastructure. Development and maintenance of green infrastructure is affordable as compared to development of new storm and sewer infrastructure. Also, many studies have proved that green spaces have multitude of physiological and social benefits on the urban dwellers apart from its environmental benefits. Integration of green-grey-blue infrastructure can help in increasing quality of life, designing citizen oriented public spaces and improve ease of living in our cities.

A case study wherein all the 3 infrastructures are interwind to deliver a project which is of national, spiritual and religious importance. An integrated ganga conservation mission “Namami Gange” was approved as the flagship programme for abatement of pollution, conservation and rejuvenation of the river. The budgetary outlay of this mission is Rs. 20,000 crores over 5 years with a vision to create a “Nirmal Ganga” as well as “Aviral Ganga”. The mission statement includes:

·       to restore the self-purifying and special properties of Ganga-Jal

·       comprehensive study on communities depending on Ganga

·       spatial mapping

·       strong sewerage infrastructure

·       abatement of industrial pollution

·       development of low-cost sanitation facilities

·       promotion of organic farming along the river bank

·       riverfront development for major ghats

·       afforestation on a massive scale through public participation

·       maintain ecological integrity by conserving the Gangetic flora and Fauna.

A consortium of 7 IITs prepared a detailed action plan and identified some special properties such as the self-cleansing properties of Ganga Jal. They recommended to maintain the BOD levels, regular water monitoring and release of special naturally occurring bacteria into the river so as to conserve it. States were guided to prepare DPRs to construct Sewage Treatment Plants (STP) and obstruct the discharge of any kind of untreated wastewater directly into the Ganga. STPs have now been operationalized in over 80% of cities lying along the river and all works have been awarded.

A social impact analysis and a study to determine the dependence on the Ganga for livelihood has been done to understand the problems faced by these communities and address them through strategic interventions. The interventions were made through proper designing of riverfronts, ghat redevelopments and reserving ample space for these communities involved in activities such as Mundan, doing last rites of people and other religious cum spiritual activities. Also, dumping in open was prohibited and people were convinced to use toilets for answering nature’s call. Regular inspection of black spots and their beautification was done to prevent people littering those spots again.

For all these initiatives to be long-term it is important that they are economically viable and self-sustainable. It was recommended to start water cargo through the river course and for this a minimum 3m depth has to be maintained all year round. Regular desludging and desilting of river bed are recommended. Passenger cruise are planned on Ganga along with diving activities for watching the special Gangetic Dolphins. At major urban centers, riverfront development with building of new ghats, gardens, pathways and cycle-tracks are undertaken. Laser shows, water fountains and annual fairs are also planned along the river. All these activities would generate a chunk of revenue for local businesses, artisan, dependent communities, increase tourist inflows and would automatically maintain the clean, Nirmal and Aviral state of the Ganges.

Once completed Namami Gange would provide multitude benefits to all the areas along it and indirectly benefit the national environment and economy. It would reduce frequent flooding of low-lying areas every monsoon, provide fertile silt to farmers, help grow riverine biodiversity, absorb carbon emissions and most importantly give a pleasant living experience to communities along the river. It would be the best case wherein Green infrastructure is built and developed in tandem and integration with Grey and Blue infrastructure.








climate resiliencedisaster managementNamami gangeimpact analysis
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