The Results of Field Measurements of Methane Flux from Various Reservoirs

The article presents the results of measurements of the specific flux of methane from the surface of different types of reservoirs on the ETR in August 2021. The selected reservoirs (Ivankovskoye, Tsimlyanskoye and Chirkeyskoye) differ in flow rate, climatic features, and anthropogenic load. The main factors of differences in the specific flux of methane from the surface of water reservoirs, which amounted to 10.5–334, 13–183, 0–1,3 $\frac{mgC}{m^2*day}$ respectively for the Ivankovskoe, Tsimlyanskoe and Chirkeyskoe reservoirs, were revealed. Spatial differences in methane content and emissions are determined by the nature of the bottom sediments, the depth of the station, the productivity of the reservoir, the presence of stratification and oxygen-free conditions in the bottom layer. The emission from the surface of each reservoir was estimated. Despite the fact that the largest specific flux was measured at the Ivankovskoe reservoir, its contribution to atmospheric emissions is 43 times less than that of the Tsimlyanskor reservoir due to its smaller area. A relatively insignificant methane emission in absolute magnitude was detected for the Chirkeyskoye reservoir, despite the fact that the capacity of Chirkeyskaya HPP is 4.7 times greater than the Tsimlyanskaya HPP and 33.3 times greater than the Ivankovskaya HPP. When estimating global methane emissions, when using empirical dependencies or the analogy method to estimate emissions from unexplored reservoirs, it is extremely important to take into account not only the climatic zone in which the reservoir is located and its own characteristics, but also the conditions for the formation of runoff in the catchment and its landscape features.