Purbasthali is a village with a police station and a rail station in Purbasthali II CD block in Kalna subdivision of Purba Bardhaman district. It is located 120 km north from Kolkata. Also known as Chupi Char, it lies on the banks of a large oxbow lake created by the Ganges river and is only 8 km from the old and holy town of Nabadwip. The 2–3 km long lake attracts migrants and water birds. The Purbasthali area has a fairly high level of arsenic in the ground water. And this place was popular for teaching ancient language Vedic Sanskrit, The famous & oldest educational institution in this village is "Purbasthali Nilmani Brahmachari Institution" which was founded in the year of 1887 by Dr. (Prof) sir Upendranath Brahmachari.
Geography
Location
Purbasthali lies close on the Tropic of Cancer. Purbasthali is a large block with a number of villages adjoining a large oxbow lake, created by the river Ganga, on its Western bank, in Purba Bardhaman district of West Bengal. It is 120 km north from Calcutta. On the Eastern bank of the river lies the old and holy town of Nabadwip. The entire Gangetic Isle complex of Purbasthali extends between the geographical coordinates from 88° 19' 45" to 88° 22' E longitude and 23° 26' to 23° 26'45" N latitude.
Police station
Purbasthali police station has jurisdiction over parts of Purbasthali I and Purbasthali II CD Blocks. The area covered is 180.3 km2.
Physiography
Purbasthali is located on the agriculturally rich alluvial plains between the Bhagirathi, Ajay and Damodar rivers. Temperatures in this region varies from 17-18 °C in winter to 30-32 °C in summer. The whole area of Purbasthali is covered with greenery, fruit-gardens, flower-gardens and agricultural fields producing a considerable amount of vegetables and fruits for export.
Purbasthali region is located in the flood plains two major rivers Damodar and the Ganga. The wetland with the river course form a half moon shape between Nabadwip and Purbasthali . Topographic configuration is the typical monotonously low dipping Gangetic plain of West Bengal with an average height of 14 metres above mean sea level. During monsoon river gets flooded, with the water level within the wetland getting higher and under heavy rains the enclosed islands get submerged. The area is extremely rich in alluvial soil content. Hence an intense agriculture is practiced on both sides of the river. Main crops Rice, maize, corn, jute, mustard, potato and all sorts of vegetables are the main produce. There are a number of fruit orchards and horticulture gardens flank the river course. Even on the riverine isle and sandy river banks cultivation goes on during the post monsoon period from September till June. Banks of the channel and river course is dotted with villages under dense tree cover while paddy fields and grass lands border the wetland.
The Oxbow Lake
The oxbow lake of Purbasthali sprawls over an area 3.50 km2. in the post monsoon period of winter months. Beyond the lake, this river fed eco-system also forms a cluster of large and small islands comprise Purbasthali Gangetic Isle Complex. Formed by the meandering river Ganga, over last 40 years, the area has transformed into a closed loop, allowing emergence of the oxbow lake. This channel of water course in a length of about 10 kilometers feeds the oxbow lake with thin connectivity with the main river with shoals forming at the river mouth. The process of rapid and growing sedimentation threatens to cut off the channel in near future.
Thus the present course of the main river shifts further eastward while the original bed holds the loop with stranded water. Remote sensing images of the wetland clearly establishes the differences of turbidity between the main river and the wetland which has sandy clay sediment and crystal clear waters because of sedimentation of suspended solid particles in the stagnant stretches.
Geology
On the basis of Geo-tectonic considerations, Purbasthali-Nabadwip region has been undergoing steady changes since time immemorial. River course has changed many times, due to geo-tectonic movements, forming small islands and oxbow lakes over last hundreds of years. The tectonic plates here are under constant collision resulted the changes in river course. A comparative study of the Survey of India topographic sheet published in 1973 with the remote sensing images of 1989-90&1992-93 coupled with observations from recent field visits, confirms the process of formation of this vast wetland besides some small but constant changes in topography occurring every year.