Analysis of Flooding Effects on the Msingi Masonry Arch Bridge in Mkalama, Singida, Tanzania

Abstract

Human induced hydraulic factors have emerged as the leading cause of 
bridge failures since the 1990s, accounting for approximately 50% of 
incidents recorded in the authors' database. These failures often occur 
without warning and result in substantial structural damage. With the 
intensifying impacts of climate change globally and particularly in 
Tanzania, such events are projected to become more frequent. Among 
hydraulic causes, flooding poses the most significant risk, primarily 
through mechanisms like erosion, high hydraulic forces, and 
sedimentation.This study assesses the vulnerability of the 
MsingiMasonry Arch Bridge to flooding, examining both immediate and 
long-term impacts on its structural integrity. It evaluates the bridge's 
exposure to flood-related hazards and compares the original design 
discharge capacity of 1497.57 m³/s with the updated estimate of 
1777.90 m³/s, revealing a critical under-capacity during peak flows. 
Based on these findings, the study proposes adaptive strategies to 
enhance the bridge’s flood resilience.Key recommendations include 
reinforcing embankments with stone retaining walls, raising the bridge 
elevation to accommodate future flood levels, and redesigning piers 
with upstream V-shaped walls to reduce debris accumulation. 
Additionally, the study advocates for community engagement through 
awareness programs and the preservation of natural riverbank 
vegetation to mitigate erosion. These measures aim to inform 
stakeholders and serve as a reference for flood-resilient infrastructure 
planning in similarly vulnerable regions.