Carbon stock estimation in the catchment of Kotli Bhel 1A hydroelectric reservoir, Uttarakhand, India

Constructions of dams/reservoirs all over the world are reported to emit significant amount of greenhouse gases (GHGs) and are considered as environmental polluters. Organic carbon is contributed by the forest in the catchment, part of soil organic carbon is transported through the runoffs to the reservoir and undergoes aerobic and anaerobic degradation with time to release GHGs to the atmosphere. Literature reveals that no work is available on the estimation of 'C' stock of trees of forest catchment for assessing/predicting the GHGs emissions from the reservoirs to atmosphere. To assess the GHGs emission potential of the reservoir, an attempt is made in the study to estimate the 'C' stock in the forest catchment of Kotli Bhel 1A hydroelectric reservoir located in Tehri Garhwal district of Uttarakhand, India. For this purpose, the selected area was categorized into the site-I, II and III along the Bhagirathi River based on type of forest available in the catchment. The total carbon density (TCD) of tree species of different forest types was calculated using diameter at breast height (dbh) and trees height. The results found that the TCD of forest catchment was found 76.96 Mg C ha−1 as the highest at the site-II and 29.93 Mg C ha−1 as lowest at site-I with mean of 51.50 Mg C ha−1. The estimated forest 'C' stock shall be used to know the amount of carbon present before and after construction of the dam and to predict net GHGs emissions. The results may be helpful to study the potential of a given reservoir to release GHG and its subsequent impacts on global warming/climate challenges.