Alick R Mwanza^1,, Edwin Nyirenda², Wilma S Nchito³

The Lukanga swamps are a part of the Kafue River catchment. It lies about 30km to the east of the Kafue River. It is connected to the Kafue River mainly through the Munwinu and Lukanga channels and during peak floods some waters of the Kafue River are said to back into the Lukanga swamps. This study thus modelled the surface water exchange between the Kafue River and the Lukanga swamps in order to understand the surface flow interactions between the Kafue River and the Lukanga swamps. The modelling employed graph theory through which the water system was recognised as a graph of 3 nodes and 3 edges. Historical water levels observed over a period of 81 months were used as input variables whereas elevations obtained from channel profiles from a corrected SRTM DEM were used as the input constants. The elevations represented channel floor. The results showed that there were 56 months in which the network had flow in all the edges, that the Lukanga channel flowed throughout the year from the Lukanga swamps to the Kafue River and that the Munwinu channel only flowed from the Kafue River to the Lukanga swamps whenever there was flow. Thus the Munwinu channel as well as the Lukanga channel does not present bidirectional flow at all.

graph theory, Lukanga swamps, Kafue River, surface water exchange, surface water modelling