The Impact of Land Use Activities on Vegetation Cover and Water Quality in the Lake Victoria Watershed

Abstract

Abstract:The impact of land use activities on loss of vegetation cover and water quality was assessed in three selected sites within the Lake Victoria Basin using remote sensing technologies and standard water quality analysis techniques. The three study sites were: (i) Nzoia River Basin (Kenya), (ii) Nakivubo Wetland (Uganda) and (iii) Simiyu drainage basin (Tanzania). Lake Victoria is the second largest fresh water lake in the world and is served by a drainage basin area of over 193,000 km 2 , traversing five East African Community States; Kenya, Uganda, Tanzania, Rwanda and Burundi. This paper examines the impact of land use activities on vegetation cover and water quality based on remote sensing and Geographical Information Systems analysis combined with chemical and physical water analysis. The quality of the effluent generated by the industries found within the study sites and their effects on downstream discharge was also determined. Pesticide residues in soil and water samples were determined using analytical standard methods. Soils from some selected fields in Nzoia River basin showed high levels of compounds such as aldrin, dieldrin, endosulfan, DDT, and endrin which are together referred to as persistent organic pollutants (POPs). The physical and chemical analysis of water quality revealed high levels of phosphates and nitrates along the agricultural zones of River Nzoia Basin. The satellite images revealed that in all the three study sites land vegetation cover has continuously reduced in size. The extent of environmental degradation caused by agricultural, domestic and industrial wastes and how this affects loss of vegetation cover and water quality is discussed.

Assessing Land Use and Land Cover Changes in the Murchison Bay Catchment of Lake Victoria Basin in Uganda

“…The results found in this study are also consistent with that of Twesigye et al (2011) who observed that, built-up was increasing while forestland is decreasing around the Nakivubo wetland which is within the area studied. However, the extent of change differ due to the area of land considered and the classification method used.…”

Relationship between water quality variations and land use in the Batutegi Dam Watershed, Sekampung, Indonesia

“…The land use characteristics of river watersheds are directly related to downstream lake and reservoir environments, with negative influences being reported in many previous studies (e.g. Beaver et al., ; Fraterrigo & Downing, ; Lizotte et al., ; Nielsen et al., ; Pilgrim, Mikhailova, Post, & Hains, ; Soranno, Cheruvelil, Wagner, Webster, & Bremigan, ; Twesigye, Onywere, Getenga, Mwakalila, & Nakiranda, ). River water chemistry is controlled by numerous natural and anthropogenic factors, including pollutants from point and nonpoint sources (Ahearn et al., ), transported downstream via river channels.…”

Application of phytoplankton community structure for ranking the major riverine catchments influencing the pollution status of a lake basin

“…The vitality of the lake has been adversely affected, however, by waste discharges from various activities around the lake (Njiru et al, 2012). The impacts of pollution from agricultural, municipal and industrial discharges, for example, are visible in some of the rivers draining into the lake and along its shoreline, especially at Port Victoria in Busia and Winam Gulf in Kisumu (Twesigye et al, 2011). Cyanobacteria blooms also are currently becoming an increasingly common phenomenon near the shores of Lake Victoria (Lung'ayia, M'Harzi, Tackx, Gichuki, & Symoens, 2000).…”