Land use/land cover change impacts on streamflow of Mkomazi River Catchment in Pangani River Basin, Tanzania

ABSTRACT Tanzania faces pressing environmental challenges from land use and land cover changes (LULCC), which significantly impact hydrological responses. This study evaluates LULCC impacts on the Mkomazi River Catchment's streamflow in the Pangani River Basin, Tanzania, from 1995 to 2021. Utilizing satellite imagery, historical streamflow, and climate data, the soil and water assessment tool (SWAT) was applied to simulate LULCC effects on streamflow, emphasizing seasonal shifts and components such as surface runoff (SURQ), groundwater flow (GWQ), and lateral flow (LATQ). Findings showed that, built-up areas increased by 22.1%, while forest cover decreased by 16.4%. Cropland expanded by 10.3% by 2021, and barren land increased by 5.1% from 2008 to 2021. Wet season streamflow rose from 38.9 to 45.4 m3/s, while dry season flow dropped from 13.4 to 8.3 m3/s. Monthly SURQ increased from 9.6 to 22.2 mm, GWQ declined from 18.3 to 8.3 mm, and LATQ dropped from 0.9 to 0.2 mm, largely due to deforestation and encroachment. The results highlight the need for effective land use management strategies in the Mkomazi River Catchment to mitigate the negative effects on water resources and ensure sustainable hydrological conditions for the catchment's sustainable development.