Urban flood mapping using HEC-RAS: A case study of the Lubigi catchment in Kampala, Uganda
(2025) In TVVR 5000 VVRM01 20251Division of Water Resources Engineering
- Abstract
- Urban flooding poses severe risks to lives, property, and infrastructure, particularly in rapidly urbanizing cities like Kampala, Uganda. This study focuses on the Lubigi catchment, one of Kampala's largest drainage basins, which experiences frequent pluvial flooding intensified by urban encroachment, poor drainage infrastructure, and wetland degradation. To assess flood risks, a 1D and a 2D model were developed using HEC-RAS, based on DEM data, design storms, and field observations. The 1D and 2D flow-only models generate flow-specific flood maps, while the 2D "rain-on-grid" approach evaluates surface flooding across the catchment based on precipitation. Calibration was performed using recorded water levels and the corresponding rainfall... (More)
- Urban flooding poses severe risks to lives, property, and infrastructure, particularly in rapidly urbanizing cities like Kampala, Uganda. This study focuses on the Lubigi catchment, one of Kampala's largest drainage basins, which experiences frequent pluvial flooding intensified by urban encroachment, poor drainage infrastructure, and wetland degradation. To assess flood risks, a 1D and a 2D model were developed using HEC-RAS, based on DEM data, design storms, and field observations. The 1D and 2D flow-only models generate flow-specific flood maps, while the 2D "rain-on-grid" approach evaluates surface flooding across the catchment based on precipitation. Calibration was performed using recorded water levels and the corresponding rainfall data. The resulting flood maps indicate flood risks along both main and secondary channels, with flood depths and extents increasing with storm intensity. The study further highlights the impact of limited available data on model accuracy. Proposed flood risk management strategies include structural improvements and maintenance of urban drainage systems to enhance flood resilience. This research emphasizes infrastructure improvements and implementation of effective flood mitigation measures in flood-prone urban catchments. (Less)
- Popular Abstract
- Floods are the most common natural disaster worldwide, posing serious risks to lives and homes. In Kampala’s Lubigi catchment, about 7 in 10 households have experienced flooding.
To show where water is most likely to accumulate during heavy storms, three computer models were developed to map how stormwater moves through Lubigi’s channels and across its neighbourhoods.
This research set out to better understand these floods and improve the ability to forecast them. Reliable prediction is key, without it, authorities and communities have little chance to prepare or protect against flooding.
Although limited data remains a major challenge in Kampala, the models still provide valuable insights. The resulting flood maps reveal that both the... (More) - Floods are the most common natural disaster worldwide, posing serious risks to lives and homes. In Kampala’s Lubigi catchment, about 7 in 10 households have experienced flooding.
To show where water is most likely to accumulate during heavy storms, three computer models were developed to map how stormwater moves through Lubigi’s channels and across its neighbourhoods.
This research set out to better understand these floods and improve the ability to forecast them. Reliable prediction is key, without it, authorities and communities have little chance to prepare or protect against flooding.
Although limited data remains a major challenge in Kampala, the models still provide valuable insights. The resulting flood maps reveal that both the depth and spread of flooding increase with storm intensity across all channels studied. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9211760
- author
- Folgner, Louisa LU and Finjan, Michael
- supervisor
- organization
- course
- VVRM01 20251
- year
- 2025
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Flood mapping, Urban drainage, HEC-RAS, Pluvial flooding, Kampala, DEM
- publication/series
- TVVR 5000
- report number
- TVVR-25/5009
- ISSN
- 1101-9824
- language
- English
- additional info
- Examiner: Magnus Larson
- id
- 9211760
- date added to LUP
- 2026-01-05 18:48:13
- date last changed
- 2026-01-05 18:48:13
@misc{9211760,
abstract = {{Urban flooding poses severe risks to lives, property, and infrastructure, particularly in rapidly urbanizing cities like Kampala, Uganda. This study focuses on the Lubigi catchment, one of Kampala's largest drainage basins, which experiences frequent pluvial flooding intensified by urban encroachment, poor drainage infrastructure, and wetland degradation. To assess flood risks, a 1D and a 2D model were developed using HEC-RAS, based on DEM data, design storms, and field observations. The 1D and 2D flow-only models generate flow-specific flood maps, while the 2D "rain-on-grid" approach evaluates surface flooding across the catchment based on precipitation. Calibration was performed using recorded water levels and the corresponding rainfall data. The resulting flood maps indicate flood risks along both main and secondary channels, with flood depths and extents increasing with storm intensity. The study further highlights the impact of limited available data on model accuracy. Proposed flood risk management strategies include structural improvements and maintenance of urban drainage systems to enhance flood resilience. This research emphasizes infrastructure improvements and implementation of effective flood mitigation measures in flood-prone urban catchments.}},
author = {{Folgner, Louisa and Finjan, Michael}},
issn = {{1101-9824}},
language = {{eng}},
note = {{Student Paper}},
series = {{TVVR 5000}},
title = {{Urban flood mapping using HEC-RAS: A case study of the Lubigi catchment in Kampala, Uganda}},
year = {{2025}},
}