ANALYZING THE MORPHOLOGICAL CHANGES OF RIVIRIVI RIVER’S CHANNEL, ITS CAUSES AND IMPACTS: A CASE STUDY OF MANYONGA VILLAGE, T/A NKAYA IN BALAKA DISTRICT.

The morphology or physical form of a river plays a vital role in shaping the surrounding environment and impacting the lives of communities residing along its banks. This study examines the morphological changes occurring in the Rivirivi River, with a specific focus on Manyonga Village located in Traditional Authority Nkaya, Balaka District. The primary objectives are to analyze the extent and patterns of these morphological changes, identify the underlying causes driving these changes, and assess the impacts on the local community.
The research employs a remote sensing approach, utilizing satellite imagery spanning multiple decades (1993, 2008, and 2023) to quantify changes in the river's course, erosion patterns, and accretion areas, thereby detecting shifts in the river's path. Additionally, changes in land use/cover and linear regression and Pearson correlation coefficient (r) analyses were conducted on precipitation and discharge data to determine the influencing factors and impacts of the Rivirivi River's changes.
The results indicate that an area of 794.361392 square meters of Manyonga Village has been eroded, representing 0.26% of the total eroded area. The total eroded area is 288,448.64 square meters, accounting for 76.16% of the study area. Accretion or the deposition of sediments, has occurred over an area of 75,573.63 square meters, making up 19.95% of the study area, while 14,703.74 square meters (3.88%) remained unchanged.
The study contributes to a comprehensive understanding of the dynamic nature of the Rivirivi River and its implications for the Manyonga Village community. The findings provide insights into the interplay between natural processes, anthropogenic activities, and climate variability, informing sustainable river management strategies and enhancing resilience in riparian communities.

The primary objectives are to analyze the extent and patterns of these morphological changes, identify the underlying causes driving these changes, and assess the impacts on the local community. The research employs a remote sensing approach, utilizing satellite imagery spanning multiple decades (1993, 2008, and 2023) to quantify changes in the river's course, erosion patterns, and accretion areas, thereby detecting shifts in the river's path. Additionally, changes in land use/cover and linear regression and Pearson correlation coefficient (r) analyses were conducted on precipitation and discharge data to determine the influencing factors and impacts of the Rivirivi River's changes. Accretion or the deposition of sediments, has occurred over an area of 75,573.63 square meters, making up 19.95% of the study area, while 14,703.74 square meters (3.88%) remained unchanged.

The Balaka District is situated in the Republic of Malawi's Southern Region. Its boundaries with Ntcheu, Mangochi, Machinga, Zomba, Blantyre, and Neno are in the northwest, northeast, southeast, south, and southwest, respectively. 2.4 percent of Malawi's total land
area, or 2,193 km2, is covered by the district. Latitude 14°59'15.38"S and longitude 34°57'22.23"E are the coordinates for Balaka District. Due to its location on the eastern end of the Great Rift Valley, the Balaka District has a varied topography with elevations varying from around 350 to 800 meters above sea level (Balaka District Council, 2017).
Ridges and natural drainage networks make up the district's topographical features. May and September are transitional months between the two separate seasons in the Balaka district. These are the two seasons: October to April is the rainy season; the cold, dry season runs from June to August. The region receives 750 mm of rain on average every year. The best rains for agricultural planting often occur in mid-December, however the rainy season officially begins by the end of October (Jury, 2014). The ideal period to grow food with rain-fed agriculture is between December and March, when the soils are moist. With an average annual temperature of 25°C, the district frequently sees hot to warm weather, with the highest temperatures occurring around the Shire River. In the district, temperatures are usually lowest in June and July and highest in October and November (Balaka District Council, 2017).
T/A Nkaya is found to the south of Balaka district and it has a total population of 45,351 people according to 2018 Malawi Population and Housing Census main report. It has households approximately 10,078.
Major rivers in the district are Shire, Rivirivi, Chimwalire, Nkasi, Lisungwi, Naliswe, Mulunguzi, Muthe, and Kalambo (Balaka District Council, 2017). The Rivirivi River basin lies between the central region district of Ntcheu and the southern region district of Balaka. It is divided into three parts: the upper and lower portions of the kirk ranges, the middle valley, and the lower valley, which fall within the great east African Rift Valley System. The river is vital to residence of Balaka as farmers use it for irrigation farming, fishing, domestic and other commercial activities to improve their livelihoods (Chimtengo et al., 2014).
Chimtengo et al., 2014 analyzed the changes in water availability to assess environmental water requirements in the Rivirivi River and the aim was at investigating some of the causes of these changes. Mavuto Chimtengo conducted another study on the Rivirivi River in Ntcheu District in 2010 to investigate the effect of traditional water allocation practices on environmental flows.
However, there’s a need to analyze morphological changes of this river as it shows that it is shifting towards Manyonga Village, T/A Nkaya in Balaka District (google images to be shown at the appendix as scientific proof of this slow onset event). All elements of vulnerability are exposed to this risk. Houses, mosque and graveyard are at high risk of being collapsed by the meandering of the river.

Traditional authority: TA Nsamala

District: Balaka

Coordinates: -15.08565, 35.0101