Abstract
Small dams play an active role in the global carbon cycling through the breakdown of organic material and
release of greenhouse gases (GHG), carbon dioxide (CO2) and methane (CH4). GHG emissions from
waterbodies around the world have been well studied, however, this is the first high level estimate of
GHG fluxes from waterbodies within South Africa, mainly in Gauteng. These waterbodies have been
known to have increased nutrient levels as a result of anthropogenic activities, such as urbanization and
agricultural activities. These activities cause variability within the water body and as a result affect the
GHG emission flux rates. It is well known in the literature that changes in water quality parameters affect
GHG flux rates. Additionally, the literature suggests that it is important to consider both spatial and
temporal variability, as short-lived biogeochemical hotspots or hot moments can be observed. Here we
present the data from six different study sites, where spatial heterogeneity was considered within each
study site. In comparing these results to global syntheses, it was found that Gauteng dams have a greater
flux rate per meter squared than the global average. Furthermore, since emissions from dams are not
includes in the SA inventory the 28,422.4 Gg CO2eq attributed the AFOLU sector in the national GHG
inventory is being underreported. The overall Gauteng estimation considered as many parameters as
possible, including water quality, spatial and seasonal effects as well as diurnal effects. It was found that
on average Gauteng alone will emit 4,402.2 Gg CO2eq/year, or 15.5% and 14.9% of the forecasted 2020
and 2030 AFOLU GHG inventories for South Africa.
Keywords: GHG Emissions, Biogeochemical Processes, Eutrophication, AFOLU, Upscaling