Himalayan Geology, Vol. 41 (1), 2020, pp. 51-62, Printed in India
Sedimentation rate (210Pb and 137Cs), grain size, organic matter and bathymetric studies in Renuka Lake, Himachal Pradesh, India
PRANAYA DIWATE1,3*, NARENDRA KUMAR MEENA1, RAVI BHUSHAN2, SUNDEEP PANDITA3,
K.R. CHANDANA2, PAWAN KUMAR4
1Wadia Institute of Himalayan Geology, Dehradun, 248001, India
2Physical Research Laboratory, Navrangpura, Ahmadabad, 380009, India
3Department of Geology, University of Jammu, Jammu, 180006, India
4Department of Environmental Sciences, Central University of Himachal Pradesh, Dharamshala,176215, India
*Email (Corresponding author): pranayadiwate7@gmail.com
Abstract: The present study is carried out to determine the sedimentation rate, grain size, organic matter and bathymetry of the Renuka Lake situated in the Lesser Himalaya. The 210Pb and 137Cs radioactive dating technique used for the determination of sedimentation rate indicated 0.78 cm/year and 0.51 cm/year (~0.64 cm/year) for the period of past 61 years respectively. This sedimentation rate, when compared with the other western Himalayan lakes,is far higher where the weathering prone lithology of the catchment rocks and increasing anthropogenic activities are seen as causal factors. The grain size analysis from the surface sediment showed the dominant contribution of silt (45-82 %); followed by sand and clay and the transport of sediments from the catchment to the lake is controlled mainly by the rolling and suspension mode and poorly sorted. The total organic carbon content observed in the range of 0.1-5.7% isfound to be in a positive correlation with the depth of the lake. The bathymetric measurement inferred depth of the Renuka Lake from 0.30 to 13 m from margins to the center, respectively, which is lowest mainly toward western where excessive erosion due tohigher tourist activities and construction works takes place. The Renuka Lake is a Ramsar site (wetland site designated to be of International importance under the Ramsar Convention from 8th November 2005) of national significance and requires mitigation measures in order to reduce sedimentation rate and maintains its natural status.
Keywords: Sedimentation rate; Bathymetric measurement; Radioactive dating technique; Texture analysis; Total organic carbon.
