Bathymetric and Sediment Assessment for the Lukanga Swamps in Central Province, Zambia

Abstract

Abstract Globally, wetlands are under threats and Lukanga Swamp, a wetland of international significance and a Ramsar site, is one of them. The aim of the study was to carry out bathymetric and sediment assessment of the Lukanga Swamp so as to provide further insights into the gravity of sediment load and ascertaining the extent of degradation of the wetlands, and the threats to it. An Hydrographic Survey Boat (HSB) Sonar Model RC-S2 mounted with a Trimble Hemisphere OmniSTAR Virtual Base Station (VBS) for Differential Geographic Positioning System (DGPS) was used to measure water depths across the Swamp. Data on sediment depth was collected using sediment coring method with the aid of a Graduated Sediment Depth Rod (GraSEDD). In sections of the swamp where there were too many weeds, GraSEDD was also used to determine water depth data, instead of the HSB. Photography was also used to collect relevant qualitative data. Quantitative bathymetric and sediment data were analysed using Inverse Distance Weighted (IDW) in ArcMap 10.4 Environment. The swamp water and sediment depths ranged from 0.2m to 4.77m and 0.03m to 2.11m, respectively. The findings showed that at the time of survey, the water stored in the Swamp was about 2,918 Million Cubic Metres (MCM) and about 1,200 MCM of the Swamp’s capacity was lost to sedimentation. The study generally concludes that Lukanga Swamp has significantly lost the original storage capacity, a problem, which is recommended to Nature-based Solutions (NbS) so as to preserve the pristine of the natural habitat.