Assessing the extent of encroachment on Kinawataka wetland, Kampala city, Uganda

Abstract

Wetlands provide a lot of ecosystem services which include water purification, flood control and climate moderation. They are carbon sinks absorbing greenhouse gases, provide food, medicine and water supply. With the increasing population, industrial development and urbanization, wetlands become more susceptible to encroachment. The objectives of the study were; (I) to determine the dynamics and magnitude of land cover change in Kinawataka wetland, (II) to determine the spatial and temporal variation in coverage of Kinawataka wetland between 2000 and 2020 and (III) to determine the land cover and land use types encroaching the wetland. The study heavily depended on GIS and remote sensing techniques to analyze high resolution satellite images of 2002, 2010 and downloaded from Google earth pro software. Digitization was used to classify the different forms of encroachment on the wetland hence coming up with digitized maps for the different years using QGIS software. The classification system used for the study consisted of the following classes; built up and bare ground, agricultural fields, wetland vegetation and open water. The different vector layers of land use/cover classes were analyzed in QGIS software to determine the total area covered by the different classes in years 2002, 2010 and 2020. The population of the area was used was an ancillary data to assist in the analysis and was got from UBOS. The results showed that there was an overall decrease in wetland vegetation from 840.3 ha (76.9%) in 2002 to 634.1 ha (58%) in 2020 and in agricultural fields from 164.3 ha (15%) in 2002 to 49.9 ha (4.6%) in 2020. There was also an increase in both built up and bare ground as well as open water from 72.6 ha (6.6%) in 2002 to 358.6 (32.8%) and 15.9 ha (1.5%) in 2002 to 50.5 ha (4.6%) in 2020 respectively. Built up area and agricultural fields were the most conspicuous land cover/use types that encroached on the wetland between 2002 and 2020. The study recommends that there is proper demarcation of wetland boundaries by the authorities and also raising public awareness about the importance of the wetland to the community.