Estimation of Methane Emissions from Reservoirs Based on Country-Specific Trophic State Assessment in Korea

It has been reported that significant quantities of greenhouse gases are emitted from wetlands, from which emissions and their contributions to global warming have received much less attentions. Thus, a refinement to the previous published guidelines has recently been made to provide an updated and sound scientific basis for the purpose of supporting the preparation of national inventories. This study is aimed at demonstrating the applicability of the refinement for estimating methane emissions from reservoirs in the Republic of Korea. It is desirable to take the direct measurement of total methane fluxes across the reservoir surface, which may require a substantial amount of research efforts though. Alternatively, methane emissions from individual reservoirs may be estimated with relevant parameters accounting for the regional environmental characteristics. The assessment of trophic state has been employed to better represent the emissions behavior of reservoirs, based on which the methane emissions from local reservoirs in Korea are estimated. It is noted that the country has developed its own water quality index with the consideration of environmental characteristics. The seasonal variations in methane emissions are tested for their statistical significance and it is proposed that the emission estimates can be predicted from the trophic state assessment with the application of regression analysis. Following the guidelines prescribed by the refinement and procedures outlined in this study, the results from emissions estimation and prediction can be effectively used for the improvement of national inventories.