The effects of land use and land cover change on avulsion of rivers: a case of the White Nile basin- Pakwach district).

Abstract

Panyangu Parish-Pakwaach District is one of the parishes that boarders the White Nile in the West Nile regions of Uganda. It has undergone Land use and Land cover change because of the human related activities carried out which if not assessed would lead to catastrophic events like Avulsion. This study aimed at quantifying the Land use and Land cover changes as well as the rate at which these changes have occurred over the last Two decades and how they could lead to Avulsion of rivers. This was achieved using remote sensing techniques and Geographic Information System (GIS) to assess the changes and FRAGSTATS to quantify the changes and determine the composition and structure of the landscape in Panyangu. To that effect, images of Landsat satellites TM, were interpreted using supervised image classification technique to determine the land use/land cover changes from 2001 to 2021. The obtained results showed that Panyangu Parish has undergone land use and Landcover transformation as a result of the growing population. The changes in Panyangu between 2001 and 2021 were decrease in Subsistence Farmlands (72.6% to 54.9%), increase in built-up (0.2% to 2.2%), decrease in wetland vegetation (9.2% to 3.8%), increase in bare land (0.8% to 11.1%) and an increase in Water (16.4% to 18.2%) increase in grassland (0.3% to 9.3%) and Forest cover remained the same at 0.5%. The results from the Landscape matrices show Subsistence Farmlands as the class with the Largest Patch index (34.6%) followed by Water (18.1%), Built-up (2.01), Wetland (1.24), Forest cover (0.77%), Grassland (0.59%) and Bare land (0.35%). The Land scape matrices showed a decrease in patch size of the Subsistence Farmlands and this is an indicator of Landscape Fragmentation which is associated with high rates of soil erosion. With the Flooding that has occurred on the White Nile, these results raise a need to be concerned about the community of Panyangu Parish. Critical measures have to be taken to regulate and control the activities that take place in this place such that catastrophes like Avulsion do no occur thereby protecting both the environment and the people leaving in it.