Monday, August 24, 2009

Sirgaon Mining: State of groundwater as per NEERI report

National Environmental Engineering Research Institute based in Nagpur presented and invstigative report titled "Assessment of the depletion of ground water sources and land degradation in Sirgaon vilalge, Goa and mitigation measures" in March 2009 to the Goa bench of Bombai High Court, Panaji in respons to Sirgaon villagers Public Interest Litigation (PIL). Below are extacts from the report's page numbers 53-54.

Results and Discussions

On the basis of the data made available by the mining companies, secondary data from CGWB, interaction with the villagers and the primary data collected by NEERI team during the field visits, the following findings emerge from the present study.

i) The dug wells in Sirigaon village are getting dried up by Decemebr 08. In fact, many wells are getting dried up by October also.

ii) Most of the wells have hardly 1-2m of water column even in the month of October though the region receives significant rainfall (2000-25000mm).

iii) The mining has gone to the level of -30 to -40 m (amsl) by all the three mining companies namely M/s Rajaram Bandekar (Sirigaon) Mines, M/s Chowgule & Company and M/s Dempo mining company. The levels were confirmed by the reduced level survey undertaken by the surveyor engaged by NEERI.

iv) The wells inventorization and the subsequent reduced level survey indicated that the water table in the village is in the range 1.5-3.0 m (amsl) whereas the mining has gone to the level of -30 to -40 m (amsl). Hence, movement of the groundwater from the village side to the mining pit is possible in the case there is hydraulic connectivity between the village and the mine pit.

v) During the field visits, seepage from mine pit wall was visible fro all the three mine pit. This is evident from the field photographs (Plate 2.8) in respect of Chowgule and M/s Dempo pvt. Ltd. The seepage was more prominent in case of Dempo pit (Plate 2.9 and Plate 2.10). Though seepage was not visible in case of Bandekar (Sirigaon) ltd, it is possible that it may be masked by the water column in the pit itself.

vi) All the wells in the Sirigaon village have very shallow depth in the range of 4 m to 8 m. The lithologs provided by the mining companies indicate that the lateritic zone (water bearing) is in the range of 10-12 m. It is evident that the water scarcity in the wells is partly accentuated due to the shallow depth of wells.

vii) In view of the water scarcity experienced in the village dug wells, it is necessary that a comprehensive mitigation programme be initiated to ensure sufficient water in their wells. The significant rainfall in the area is definitely a boon to the villagers. The quality of water pumped from pit is also if good quality except turbidity and iron content on few occasion. A comprehensive programme incorporating roof top rainwater harvesting and artificial recharge is recommended for rejuvenation of the aquifer in the Village. The detailed roadmap for artificial recharge and roof top rainwater harvesting is outlined in Chapert 4 of the report.

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