Many would think it is a crazy pastime... to walk along a seemingly endless stretch of red sandy hills on a sultry morning, gathering bits of strewn plastic and paper. Yet, a group of 45 people did just that last weekend, collecting bagfuls of waste. While cleanup drives are not uncommon in the coastal city of Visakhapatnam, what makes this exercise different is the location: Erra Matti Dibbalu, a geological marvel unique to the coast of Visakhapatnam. Located between Visakhapatnam and Bheemunipatnam, the Erra Matti Dibbalu are rare red sand dunes that are a reminder of the million years of geological processes, and among the 34 notified National Geological Heritage Monument Sites of India by the Geological Survey of India. The width of the dunes, which runs for five kilometres along the coast, varies from 200 metres to two kilometres. Located at a distance of 16 kilometres from Visakhapatnam, the towering red sand dunes with patches of greenery is like a meandering maze, which takes one on a fascinating journey into one of the best kept secrets of the geological world, formed millions of years ago.
During the cleanup drive led by citizen groups including Vizag Volunteers and India Youth For Society, around 250 kilograms of waste was collected from the west side of the sandy dunes, then methodically segregated for disposal. “This is the sixth time in the recent past that we have stepped into this site to clear the trash. And each time, it is heartbreaking to witness trash piling up at this precious geo heritage spot,” says Jayshree Hatangadi, who conducts heritage walks in the city. She has been actively involved in narrating the history of the city’s prominent landmarks and leading the way towards heritage conservation. These earnest drives, involving an increasing number of locals, are an important first step towards protecting the red sand dunes. For, as experts point out, there are greater challenges ahead.“Besides being unusual, the rare sand dunes are valuable scientific documents and are an important link to the history of geological evolution,” says D Rajashekhar Reddy, advisor, Natural Heritage Division, INTACH and retired professor, Department of Geology, Andhra University. The dunes comprise a light yellow sand dune at the top followed by a brick red sand unit, and a reddish brown concretion bearing sand unit with yellow sand at the bottom.
Stating that such sand deposits have been reported only from three low latitude tropical regions in South Asia — the Teri Sands of Tamil Nadu, the Erra Matti Dibbalu in Andhra Pradesh and Red Coastal Sands of Sri Lanka – Rajashekhar adds that the dunes are very fragile and liable to natural degradation leading to a gradual loss of material. “The red sand sediments are unconsolidated and loose. Every monsoon the sediments are washed away, turning the sea a bright red. Further degradation due to human interference such as digging, climbing, littering are affecting their stability and exacerbating erosion,” he says.
Erra Matti Dibbalu has two entrances. The one on the east side can be seen from the coastal drive from Visakhapatnam to Bheemunipatnam. It takes a long walk through the sands to reach the towering dunes; the west side entrance has a watch tower, a temporary structure set up by AP Tourism, which gives a bird’s eye view of the endless stretches of sand dunes in the backdrop of the Bay of Bengal.
“Studies indicate that the area was tectonically active between 2.5 million years and 11,000 years ago and the sediments are mainly derived from the Khondalite rocks from the hinterland of the Eastern Ghats. Geologically these red sand dune sediments particularly hold significance as they are the result of the combined effect of numerous factors including global climatic changes, sea-level variations, monsoonal variability and as a result serve as valuable paleo-environment indicators,” says Rajashekhar. The area is also important from an archeological point of view. “It is interesting to note that the region was also the home to the prehistoric man as the excavations dug at several places in the region revealed stone implements of three distinctive periods and also the pottery of the Neolithic man,” adds Rajashekhar. INTACH has been pushing for recognition of a geo park for Visakhapatnam consisting of Erra Matti Dibbalu, the natural rock formations at Mangamaripeta, the million-years-old Borra Caves and the volcanic ash deposits of Araku.
In the recent past, the sand dunes have been drawing a large number of visitors. However, a lack of monitoring mechanism, regular upkeep of the spot and absence of a regulated track for visitors seem to be some of the basic hurdles in turning it into a sustainable geo-heritage site. According to Jayshree, engaging the local community in becoming the custodians of this heritage site can help them to understand its geological value. A gate, adequate security, tourist safety team and guides are some of the measures that should be implemented, she says. Measures like proper fencing of the spot, a pre-defined track for visitors may serve the purpose of preserving the spot for aesthetic purposes as well as scientific documentation. Last year, a probe was initiated by the district administration into the alleged mining at Erra Matti Dibbalu, an incident that raised alarm among heritage lovers and activists. Experts point out that the scope of the study of Erra Matti Dibbalu for understanding past environmental indicators is significant, enabling further research into past climate, sea-level oscillations and monsoon variability.