Land-use changes and community perspectives on the effects of sea water intrusion on riverine soils, vegetation, and cultivated areas in Tana River Delta, Kenya
Department of Natural Resources, Faculty of Environment and Resources Development, Egerton University, Kenya. P.O. Box 536-20115. Egerton, Njoro.
Research Article
Open Access Research Journal of Science and Technology, 2025, 14(02), 148-161.
Article DOI: 10.53022/oarjst.2025.14.2.0100
Publication history:
Received on 29 June 2025; revised on 06 August 2025; accepted on 09 August 2025
Abstract:
Deltaic ecosystems are wetlands shaped by the interaction of freshwater and seawater dynamics. However, reduced river flow, especially during the dry season, allows seawater to intrude into river channels, disrupting deltaic vegetation and causing crop losses. Elevated salinity levels adversely affect riparian soils, freshwater-dependent vegetation, and agricultural productivity, with crops like rice being particularly vulnerable. This phenomenon is currently occurring in Kenya's Tana River Delta. This study investigated land-use changes resulting from seawater intrusion and its impacts on riparian soils, vegetation including mangroves, and on adjacent cultivated areas in the Kipini and Ozi regions of the Tana River Delta. Land cover changes were analyzed using satellite imagery from Landsat, Aster, and Sentinel, spanning the period from 1999 to 2021. Over this period, the area covered by mangroves increased by 10.8%, River area expanded by 2.7%, and human-occupied areas grew from 11 hectares to 20 hectares. Conversely, grasslands and non-vegetated areas decreased by 1.8% and 20%, respectively. The mean pH of mangrove soil was 7.028±0.127, while cultivated soils had a slightly lower mean pH of 6.608±0.133. The mean salinity of mangrove soils was 0.941±0.556‰. Water salinity decreased significantly with distance from the mouth of the delta, influenced by recent El Niño rains, which diluted saline levels. These conditions supported the growth of crops and the development of young mangroves.
Keywords:
Crop loss; Delta; Mangroves; Riverine vegetation; Sea water intrusion; Wetlands
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Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0