India: Erosion Control Incorporated into Planned Community

Some Background on My Visit
During the February 2012 IECA conference in Las Vegas, I spoke with C.R. Devaraj, President of IECA’s Indian Chapter. Devaraj is the Managing Director of Charankattu Coir Mfg. Co. located in the state of Kerala in southwestern India and he was attending the conference to promote his company’s erosion control blankets made from local cocoanut and jute fibers.

I had one question for C.R. Devaraj:  “Were I to visit India this year, could you recommend any projects I could see which are successfully employing erosion control techniques and products?”  He immediately replied, “Yes, Lavasa.”  He told me a bit about the project and I looked at its website where I learned that Lavasa is a planned community in the Western Ghats, a chain of low mountains east of Mumbai (Bombay) and near the city of Pune.

C.R. Devaraj provided me with contact information for Lavasa and I eventually secured an invitation to visit the community from Krunal Negandhi, Lavasa’s Assistant VP for Projects (Environment).  I later learned that two IECA members had been directly involved with the project.  C.R. Devaraj had supplied the erosion control products used at Lavasa -- the first time he had actually provided products for an Indian project.  Also, Doug Wimble (Managing Director of Spraygrass in New South Wales, Australia and the new President of IECA’s Region 2) had provided consulting services for Lavasa’s erosion control efforts.



When I visited Lavasa in August 2012, Krunal Negandhi and his associates bombarded me with a wealth of interesting information regarding the philosophy behind the project, its objectives, progress to date, specific erosion and sediment control measures, various other environmental measures, and other important information about the community.  They also took me for several site tours to give me a first-hand look at the results of their efforts.  It would take many pages to describe their initiatives with regard to sustainable native vegetation, solid waste management and recycling, sewage treatment, renewable energy, education, health care, light industry using local materials (bamboo) and tourism.  I’ll focus on erosion and sediment control but first here is a summary of how Lavasa got started and what the project hopes to achieve.

Central pedestrian area in Lavasa with scores of condos and homes (most under construction) in background.

 

Krunal Negandhi, Lavasa's Assistant VP for Environment and a view of Warasgaon Lake on a foggy morning.

 

Members of Lavasa’s environmental team pose in front of some of their successful reclamation work.  From left to right:  Aalam Tamboli, Pramod Pokharkar, Sunil Habade, and Satish Killare   Photo provided by Krunal Negandhi.

 

A Very Brief History of Lavasa

In 1998, the government of India initiated a new Hill Station Policy to encourage the development of planned communities accessible to, but separated from, huge chaotic, unplanned, and relatively dysfunctional cities such as Mumbai. The idea for Lavasa was conceived by Mr. Ajit Gulabchand, the Chairman of Hindustan Construction Company.  He envisioned a community which would integrate living, working, and playing in harmony with nature. 

 

Construction of Lavasa started in 2002.  It is the first open (un-gated) community initiated under the Hill Station Policy.  It is also India’s first city built and governed by a private corporation.  The developers are trying to achieve environmental sustainability based on principles of the UN Environmental Program.

 

Lavasa has had its share of problems.  Construction was shut down for a time because clearances had not been granted by all the necessary departments of the notorious Indian bureaucracy.  A July 2011 article in Atlantic Magazine criticized Lavasa for constructing housing that is too expensive for the average Indian.  True enough, but I was shown modest low-cost apartments that are being provided for construction workers and other laborers.  It seemed to me an improvement over communities like Aspen and Vail, Colorado, USA where workers can’t afford local housing and have to commute to work an hour or more from trailer parks or crowded apartments where land is cheaper.  Lavasa may not be perfect but they are trying to provide an innovative model for future urban development in India.  We’ll have to check back in a few years to see how well they are succeeding.

 

Erosion and Sediment Control at Lavasa

When work started at Lavasa in 2002, erosion and sedimentation had significantly degraded the mountainous landscape where slash and burn agriculture was the norm.  Addressing these problems had been integrated into the community master plan.  For example, there would be no construction on slopes greater than 1:3 (33% or 18.4^o).  Existing green cover would be preserved where possible.  Reforestation with indigenous species was planned for steep, denuded slopes.  Measures would be introduced to raise the water table providing needed moisture for re-vegetation efforts.  Vegetated buffer zones would be created or maintained around streams to minimize sedimentation. 

 

I saw a number of sites where these elements of the master plan have been implemented.  Following are examples of some of the specific erosion and sediment control measures employed.

 



 

This steep soil dump (fill) slope above the city center has been transformed into a stable green carpet of trees and plants.  Here’s how they accomplished it:

- First, they graded the slope into the undulating surface shown in the above photos

- A jute bag toe wall was constructed at the base of the slope.  The jute bags were filled with excavated (reused) soil and wrapped with geo-mating. 

- Cocoanut coir mats were anchored to the slope above the jute bag wall.

- Vetiver (the tall grass in the photos) was planted at the base of the slope and immediately above the jute bag wall. Vetiver is famous for its long roots which counteract surface erosion.  It is unable to reproduce itself so it does not spread to areas where it is not wanted.

- The hillside was hydroseeded with a mix containing paper mulch, wood fiber, water, seed of indigenous species, and guar gum binder with rice husks.  It was seeded right after the monsoon rains started in the spring.

- Native trees were planted in scattered locations.

- A drip irrigation system was installed to help the plants and trees survive and thrive through the four month winter dry season.

 

 

Reclaimation work is underway on this hillside.  Note the jute bag wall with jute netting above on the steep hillside.

 

 



Biodegradable bamboo staples are used to anchor mats to the hillsides.

 

 

 



Horizontal PVC pipes with filter media extend 0.9 meters (about 3 feet) back into a jute bag wall to permit ground water drainage. 

 



On hillsides, water absorbing trenches (WATs) (1 meter wide and 1 meter deep) and continuous contour trenches (CCTs) (0.6 meters wide and 0.6 meters deep) trap rain water and promote infiltration.  Each trench has a maximum length of 3 meters (about 10 feet).  In areas where the trenches have been excavated, groundwater levels are rising.  They also use CCTs that drain to natural swales.



Artificial ponds and structures have been constructed along existing drainages.  These features reduce erosion by slowing down storm water runoff.  They increase infiltration, retain some water in these intermittent streams during the dry season, and enhance the aesthetic character of landscape.

 



A gabion bandhara and loose boulder structure covered with wire mesh has been constructed across an intermittent stream in the valley below a steep hillside.  Note the sediment which has collected above the dam.  Previously, the sediment would have reached Warasgaon Lake in the valley bottom.



 

Lavasa’s “leisure trail” winds along a steep mountainside which was an eroded, barren wasteland prior to reclamation four years ago and is now covered by a dense and diverse young forest.  The pathway was constructed with soil jute bags wrapped with geo-mats and covered with gravel.  The path is “stepped” to cut down on erosion.

 

 

Initially, the project team tended to rely on more traditional methods for slope stabilization such as this gabion wall next to a street.  In recent years, they have been switching to more aesthetically-pleasing, environmentally-sustainable bioengineering techniques.

 

 

Bio-diversity enhancement:  Approximately 600,000 indigenous trees and 700,000 stumps and shrubs have been planted.  The aim is to create a diverse canopy structure of trees, shrubs, and grasses.

 

Lavasa hires local people to do the planting by hand.  Farm yard manure and local mulches are used.  Some areas also require geo-mats or coir mats depending on slope and other factors.

 

In the photo above, the left side of the stream is reforested Lavasa property.  The right side is owned by local farmers and has been cleared (slash and burn) for grazing.  The grazing land is green because the photo was taken in the middle of the rainy season.  A close look reveals evidence of erosion on the recently grazed hillside. Lavasa personnel are working with local farmers to steer them away from slash and burn practices.

 

 

Lavasa has its own nursery where ornamental plants as well as native species for reforestation and erosion control get their start.  Photo provided by Krunal Negandhi.