Development of an Integrated SWAT-SEIR Mathematical Model for Assessing Climate Change Impacts on Water Security: A Lake Victoria Basin Case Study

Abstract

Climate change poses significant threats to water security globally, with the Lake Victoria Basin experiencing intensified droughts, floods, and water quality degradation. This study developed an integrated mathematical model combining the Soil and Water Assessment Tool (SWAT) with a Susceptible-Exposed-Infectious-Recovered (SEIR) epidemiological framework to assess complex interactions between climate change and hydrological processes. The hybrid model captures both water quantity dynamics through SWAT's physically-based approach and water quality contamination dynamics through the SEIR compartmental structure. Model validation achieved excellent performance with Nash-Sutcliffe Efficiency of 0.85 for streamflow and satisfactory performance for water quality parameters (NSE =0.59-0.67). The basic reproduction number (R₀ =4.69) indicated endemic contamination conditions requiring active management intervention. Sensitivity analysis revealed environmental degradation factor (μ* = 0.342) and precipitation input (μ* = 0.298) as the most influential parameters. The integrated framework successfully represents threshold behaviors and system transitions critical for climate adaptation planning.