Theme
Plenary Session
Speaker
Rowena Harrison – University of the Free State
Authors
Rowena Harrison – South African Earth Observation Network
Philippe Suchet – University of Burgundy
Johan van Tol – University of the Free State
Rowena Harrison – University of Burgundy
Abstract
A key component in addressing challenges in water resource management is the development of a comprehensive understanding of the complex relationships between soil properties, land use and management, and the hydrologic cycle. Despite the numerous studies conducted, there is a paucity of research in South Africa focusing on the relationship between soils, land types, and hydrology of wetlands and headwater streams. Controls on total organic carbon (TOC) losses at the catchment scale are poorly understood and yet these fluxes may have important consequences for ecosystem functions. This study focuses on the interactions between the pedological and hydrological processes and their interactions with dissolved organic carbon (DOC) within catchments. The study takes place in the Cathedral Peak experimental research catchments, specifically in Catchments 3, 6 and 9 which have different management histories. Water paths in each catchment have been mapped and wetlands have been instrumented with piezometers as well as the installation of two spectral probes at the weirs within Catchments 6 and 9. Water samples are collected from the piezometers and the weirs. These are filtered through a 0.47 µm filter for particulate organic carbon (POC) analysis and 0.2 µm filter for DOC analysis. The analysis is undertaken at the University of Bourgogne in France. The spectral probes installed in Catchments 6 and 9 take DOC, TOC, turbidity, electrical conductivity and temperature measurements every 15 minutes. Initial results indicate the waters of Catchments 6 and 9 have similar TOC concentration ranges between 0.6 and 1.0 mg/l, with DOC concentrations between 0.25 and 0.5 mg/l. These results indicate low DOC concentrations within both catchments. Testing of samples for stable isotope signals (13C) is planned in the near future. The results will be utilised to determine the contribution of the wetlands to carbon cycling and DOC export at a catchment scale.