Level of Degradation Along the Nairobi River Basin Riparian Zone Between 1991 and 2021

Abstract

Globally, the riparian zones have faced significant challenges related to human activities and environmental degradation. These zones, characterised by their role in filtering river water, preventing soil erosion, and regulating temperature, and crucial to maintaining ecological balance. Despite global frameworks like the Ramsar Convention and national laws in Kenya, the Nairobi River riparian zone has faced significant degradation over the past 30 years due to urbanisation, deforestation, and improper waste disposal. This degradation has compromised the riparian zone's ability to mitigate flood risks, resulting in increased surface runoff, erosion, and more frequent flood events in Nairobi City County. The research Objective was to evaluate the extent and drivers of degradation in the Nairobi River riparian zone over the past 30 years, while the research question was the primary drivers of degradation along the Nairobi River basin riparian zone over the past 30 years. The upper catchments of the Nairobi River were characterized by intensive agriculture and animal husbandry, with sparse human settlements. In the CBD, high-rise commercial office buildings and other urban developments dominated the landscape. This area also hosted industries, residential areas, and extensive road networks. The findings presented provide insights into the frequency of floods along the Nairobi River riparian zone, as perceived by respondents. The data showed 52% of the respondents (200 individuals) reported that floods occur annually. Nairobi receives the highest amount of rainfall in March, April, and May, followed by October, November, and December. From the computed cross-tabulation, the researcher determined the Chi-Square test of independence between economic activities by households living along the Nairobi River riparian zone and the frequency of floods along the Nairobi River riparian zone. The 30-year analysis of the Nairobi River riparian zone revealed severe degradation driven by intensive agriculture, urbanization, and infrastructure development. This study concludes that the Nairobi River basin riparian zone has experienced severe environmental degradation from 1991 to 2021, primarily driven by rapid urbanisation and agricultural expansion. Further research on the assessment of the impact of sustainable agricultural practices on soil health and water quality in the Nairobi River riparian zone in Nairobi County, Kenya.