Hydrogeology of Rajarhat New Town

Geology

The project area and its surrounding parts are underlain by huge thickness of quaternary sediments laid down by the southerly flowing Bhagirathi river and its tributaries. The major area is occupied by recent alluvium comprising of gray sticky clay, fine and medium sand mainly. At a depth of 120 metre or more there is a brown clay horizon of sub recent age. Average thickness of the clay layer near to the surface is about 25 metres.

Hydrogeology:

Groundwater occurs in several granular zones deposited by the river system. Sand horizons of different grades textures and colours constitute the main aquifers. In Rajarhat area due to the presence of thick clay at the top the upper aquifer gives a semi confined character. The drilling data available from the tube well drilled at Ecospace, Bengal Ambuja Complex shows that there is a thick gray clay bed upto a depth of 10 metres. From 10 to 42 metres there are several layers of fine sand often mixed with clay. This is the upper low yielding aquifer of the area. Below this there is a dark gray clay bed between 42 metre and 55 metres.  From 55 metres to 84 metres there is a bed of fine sand. Below this medium sand occurs  upto a depth of 100 metres (16m thickness). Below this upto a depth of  135metres there is fine sand.

The litho log and assembly is given in plate I

The zone between 55 metre and 135 metre constitutes a potential aquifer in this area and most of the groundwater is withdrawn from this area.

GROUNDWATER LEVEL

Groundwater level in Rajarhat block is regularly monitored. The post monsoon Groundwater level (2011) of 7 monitoring stations in and around the project area is given in the table1. With the help of the data a depth to water level zonation map is prepared which is shown in plate II.

Table 1. Post Monsoon depth to water level of Rajarhat area. (Source: SWID)

Sl NoMouza	Location	Type of well	Post monsoon DWL mbgl
1              Patharghata	Village centre	Tube well	5.5
2              Chandpur	Panchayet office	Tube well	0.85
3              Gopalpur	Health Centre	Tube well	11.25
4              Rajarhat	Bishnupur Health Adm unit	Tube well	5.53
5              Ghuni	Primary School	Tube well	9.9
6              Jagadishpur	Primary School	Tube well	7.7
7              Sukantanagar Salt Lake	Near Club	Tube well	12.3

It appears that the post monsoon depth to water level of the project area is between 8 to 9 metres below ground level. Water level is also collected from a deep tube well of the Tinkanya project site. The depth to water level of that well on25 January 2012 is 8.29 mbgl. The tube well tapped the aquifer between the depth 80m bgl to 95 m bgl.

Download SWM-GROUP quarterly note Q1 2011 nonref EN coverB.pdf

Download SWM-GROUP quarterly note Q1 2011 nonref EN coverB.pdf

WATER FOOTPRINT OF LEATHER INDUSTRY IN INDIA

Not only agricultural products contain virtual water – most studies to date have been limited to the study of virtual water in crops – but industrial products and services also contain virtual water. Leather industry is one of such industries that produce such products which have a very high value of virtual water. Similarly it also experiences a large water footprint.
The virtual water from feed, drinking and servicing is integrated over its life span to get the total virtual water content of a live animal, which is 5252 m3/animal. As the live weight of the animal is 0.545 ton, the virtual water content of bovine cattle in Canada is equivalent to 9636 m3/ton of live animal and if an animal ready to be slaughtered is traded alive the total virtual water traded is about 9636 m3/ton. The primary products of the animal are the carcass, offal, semen and raw skin. The virtual water contents of these primary products are calculated as:
• carcass 16100 m3/ton
• offal 9100 m3/ton
• semen 378800 m3/ton
• skin 14100 m3/ton
Leather industry deals with the skin and virtual water of its primary raw material is 14100m3/ton. Water footprint of a leather industry depends on its intake of raw materials and the quantum of its products. Normally leather consumes 30 m3 of water per ton of leather in the process. Out of this 2 m3 is actually consumed and 28 m3 is released into environment as waste water. This waste water contains high amount of toxic chemicals that ultimately adds to the gray water footprint of the industry. For the tanned leather from a bovine cow it costs about 16000 cubic meters of water per ton of leather considering the quantum of gray water footprint and water used for other utilities. The grey WF is calculated as the volume of water that is required to dilute pollutants to such an extent that the quality of the water remains above agreed water quality standards (Chapagain et al., 2006b).
India being a very large and potential producer of leather and leather goods Indian leather industry has a very high water footprint. By exporting leather and leather goods India exports a very high amount of virtual water. This amounts to approximately 6960 Mm3 of virtual water in 2010. The table 1 shows the present leather export of this country in 2010 (source: India Leather Portal).
Table1: India’s export figure on leather and leather goods in 2010

ITEM CAPACITY
Hides 65 million pieces
Skins 170 million pieces
Leather Footwear 909 million pairs
Leather shoe uppers 100 million pairs
Leather Garments 16 million pieces
Leather Goods 63 million pieces
Industrial Gloves 52 million pairs
Saddlery & Harness 12.50 million pieces


The water requirement of 2010 and projected water requirement in 2025 in leather industry is given in table 2.

Table 2: water requirement of leather industry in India

Water requirement in 2010 65.74 Mm3/ day
Water requirement in 2025 93.08 Mm3/ day

In India leather industry mostly depends on the groundwater resources and a part of the waste water is still being discharged into the environment causing serious environmental and human health hazards. Now time has come that industries including leather should take up some proactive measures to mitigate all adverse environmental situations.