Geospatial Data Analysis for Study of Suspended Sediments in Govind Ballabh Pant Reservoir, Singrauli Coalfield, India

Geospatial Data Analysis for Study of Suspended Sediments in Govind Ballabh Pant Reservoir, Singrauli Coalfield, India

Origin of Sediments
The origin of sediments deposited in the reservoir was determined by analyzing their clay mineral contents. Earlier studies (Friedman & Sanders, 1987) have shown that the clay mineral composition of sediments is a good indicator for identifying their provenance. Clay minerals are the products of rock alterations making silicate minerals; these reflect the mineral composition of the rocks and their weathering conditions.

The spatial distribution of K/I ratio, as determined from the clay fractions of the reservoir sediments, was analyzed using GIS (Figure-4). Following four sedimentological areas were identified in the reservoir on the basis of K/I ratio:

In the north-western part, the reservoir samples had a ratio exceeding 3 (i.e. 3.2 to 4.3), which is indicative of Gondwana provenance;
In the southern and eastern part, the reservoir samples had a very low K/I ratio (i.e. 0.7 to 1.6) indicating gneissic origin of the sediments;
On the western bank, areas with low ratios (1.7 to 2.2) were also observed indicating origin from gneisses;
The mud brought by Rihand river into the reservoir had ratio between 2.4 and 3.0 (with an average of 2.9); this indicates gneissic provenance of the sediments.

Figure-4: Clay minerals from different geological substrates of GBP reservoir.
Pollution Level of Sediments
The somewhat higher concentration of metals and trace elements may be attributed to the chemical composition of the rocks exposed surrounding the reservoir. Study of mercury concentration suggests a marginally higher value in almost all the parts of the reservoir except in the central part (Figure-5). Very high mercury pollution, i.e. (>) 1000 mg.kg-1, however, was observed close to Rihand dam where Dongia stream (nala) meets with the reservoir. The high concentration of mercury is due to the waste discharge from the chloro-alkali plant of Kanoria chemicals in Dongia nala.

Figure-5: Distribution of mercury (Hg) content in the sediments of GBP reservoir.
Conclusion
Periodic geospatial data capture and analysis offers an efficient tool for mapping of suspended sediment dispersal pattern in the reservoir. K/I ratios of the reservoir sediments indicate the provenance. Chemical analyses of the sediments show the pollution level of the reservoir. Integration of geospatial data using GIS helps in analyzing the existing status of pollution level of the reservoir as well as the source of pollutants. Follow-up remedial measures should be taken-up for efficient reservoir management based on such study.

Acknowledgement
The authors are grateful to Chairman-cum-Managing Director, Central Mine Planning & Design Institute Ltd., for his encouragement and kind permission to publish the paper in the conference. The views expressed in the paper are not necessarily those of the company to which the authors belong.

References

Electricite de France International and Groupe Charbonages de France, 1992. Environmental study of Singrauli area. Unpublished report.
Friedeman, G.M. and Sanders, J.E., 1978. Principle of Sedimentology. John Wiley & Sons.
Julius T. Tou and Rafael C. Gonzalez, 1974. Pattern Recognition Principles. Addison-Wesley Publishing Co.
Moore, G.K., 1978. Satellite surveillance of physical water quality characteristics. Proceeding of the 12th International Symposium on Remote Sensing of Environment, ERIM, Ann Arbor, MI. Vol. I, pp. 445-462.
Ritchie, J., Schiebe, F.R., and Mctenry, J.R., 1976. Remote sensing of suspended sediments in surface waters. Photogramm. Engg. & Remote Sensing. Vol. 42, No. 12, pp. 1539-1545.
Whitelock, C.H., Witte, W.G., Usry, J.W., and Gurganus, E.A., 1978. Penetration depths of green wavelength in turbid water, Photogramm. Engg. & Remote Sensing. Vol. 44, No. 11, pp. 1405-1410.

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