Page 118 - AJWEP-22-5

Asian Journal of Water, Environment and Pollution. Vol. 22, No. 5 (2025), pp. 112-128.
doi: 10.36922/AJWEP025180137

ORIGINAL RESEARCH ARTICLE

Land-use/land-cover change in the Ngerengere River
Catchment, Tanzania: Insights from 2004 to 2034

Rose Nkinda , Fredrick Ojija * , Giovanni Bacaro , and Gisandu Malunguja 1
3
1
1,2
1 Department of Earth Sciences, College of Science and Technical Education, Mbeya University
of Science and Technology, Mbeya, Tanzania
2 Department of Research and Publications, Directorate of Postgraduate Studies, Research and Publications,
Mbeya University of Science and Technology, Mbeya, Tanzania
3 Department of Life Sciences, University of Trieste, Trieste, Italy
*Corresponding author: Fredrick Ojija (fredrick.ojija@must.ac.tz)

Received: May 2, 2025; Revised: June 23, 2025; Accepted: June 26, 2025; Published online: July 21, 2025

Abstract: Land use and land cover (LULC) surrounding the Ngerengere River, Tanzania, which is a crucial water
source, has led to a rapid decline in vegetated areas. Understanding these changes is vital for informed decision-
making and sustainable river catchment management. This study assessed historical LULC trends from 2004 to
2024, projected the current trend of change to 2034, and analyzed the human activities driving the trends using
Landsat TM imagery. The study utilized both spatial and non-spatial datasets from primary sources (Landsat
imagery via Google Earth Engine and field surveys) and secondary sources (literature and government reports).
Landsat 5 (2004) and Landsat 8 (2014, 2024) images were processed using Arc-GIS and QGIS to minimize cloud
interference. Land cover classification combined unsupervised and supervised methods, validated with ground
reference points collected through GPS. A rule-based classification system used spectral indices to identify land
cover types. Classified maps were visualized and exported for further analysis. Furthermore, systematic field visits
were conducted along the catchment to assess human land use activities, that is, agriculture, settlements, and
deforestation. Results revealed a 17.6% decline in sparse vegetation between 2004 and 2014, and a further 27.01%
decrease from 2014 to 2024. Bare land increased by 8.58% over the two decades. Built-up areas rose from 0.67%
in 2004 to 5.44% in 2014, then dropped to 2.1% in 2024. In contrast, dense vegetation increased from 0.04% in
2004 to 7.13% in 2024. Overall, the land cover projection for 2034 indicates continued ecological transformation
within the Ngerengere River catchment. These shifts, primarily driven by agricultural expansion and deforestation,
underscore the urgent need for sustainable land management. The significant vegetation cover decline in the
catchment is largely due to agricultural encroachment into forested areas.

Keywords: Anthropogenic activities; Biodiversity; Climate change; Deforestation; Ecosystem; Forest; River
catchment; Water

1. Introduction biodiversity. In addition, they act as important carbon
1-3
sinks, absorbing and storing large quantities of carbon
Vegetation cover, particularly forests, plays a crucial role dioxide, thereby mitigating the impacts of climate
in maintaining river catchments, protecting watersheds change. Beyond these ecological services, forests
4-6
from erosion and sedimentation, and supporting also support livelihoods, especially in rural areas, by

Volume 22 Issue 5 (2025) 112 doi: 10.36922/AJWEP025180137