Author: Hakorimana Jean Claude

Email: jeanclaudehakorimana8@gmail.com
Location: Rwanda-Kigali
Masters’ student in Geo-Information and Environmental for Sustainable development
University of Rwanda
College of Science and Technology

Title: Assessing Environmental impact of landslides in Rwanda

Declaration

I, Hakorimana Jean Claude, hereby declare that this research review paper, titled "Assessing
Environmental Impact of Landslides in Rwanda," is my original work. I have not submitted this work, in
whole or in part, for any other degree or qualification. All sources used have been properly acknowledged
and cited within the text.

I am a Master's student in Geo-Information and Environmental for Sustainable Development at the

University of Rwanda, College of Science and Technology. My contact details are as follows:

Author: Hakorimana Jean Claude

Email: jeanclaudehakorimana8@gmail.com

Location: Rwanda - Kigali

Acknowledgement

I express my sincere gratitude to the University of Rwanda, College of Science and Technology, for
providing me with the opportunity to pursue my Master's degree in Geo-Information and Environmental
for Sustainable Development. I am particularly thankful for the guidance and support I received
throughout the research process for this review paper, titled "Assessing Environmental Impact of
Landslides in Rwanda."

I would also like to acknowledge the contributions of Dr.Ndikubwimana Innocent for his expertise,
insights, and encouragement were invaluable in shaping this work.

Finally, I extend my appreciation to College of Science and Technology and University of Rwanda for
their support played a crucial role in the successful completion of this review.

Hakorimana Jean Claude

Masters’ Student in Geo-Information and Environmental for Sustainable Development University of
Rwanda
College of Science and Technology Kigali, Rwanda
Email: jeanclaudehakorimana8@gmail.com
List of Abbreviation

DC&IR: Damage control and initial rehabilitation

DIDMAC: District Disaster Management Committees

DRR: Disaster Risk Reduction

DRRM: Disaster Risk Reduction Management

EM-DAT: International Disaster Database

EWS: Earlier Warning System

GoR: Government of Rwanda

JADF: Joint Action Development Forum

MAM: March, April, and May

MIDIMAR: Ministry of Disaster Management and Refugee Affairs

MINEMA: Ministry in Charge of Emergency Management

MINICOM: Ministry of Trade and Industry

MININFRA: Ministry of Infrastructure

NADIMAC: National Disaster Management Committee

UNDRR: United Nations Office for Disaster Risk Reduction

Abstract
Landslides pose a significant global threat, causing widespread devastation and claiming thousands of
lives annually. This study investigates the impacts of landslides in Rwanda, a country highly susceptible
to these events due to its mountainous terrain, heavy rainfall, and human activities such as deforestation
and unplanned development. The research examines the physical and human factors triggering
landslides, including steep slopes, soil properties, undercutting, heavy rainfall, and land use/land cover
changes. Furthermore, it analyzes the environmental consequences of landslides, such as landscape
deformation, degradation of water quality, destruction of forests and vegetation, and disruption of
wildlife habitats. Finally, the study identifies and discusses mitigation strategies to minimize the impact
of landslides in Rwanda. By understanding the complex interplay of these factors, this research aims to
contribute to the development of effective landslide risk reduction measures in Rwanda and other regions
facing similar challenges.

Keywords: Landslides, Land-use land Cover, Disaster, vegetation, degradation.

Chapter 1: GENERAL INTRODUCTION

1.1 Back ground information
Landslide also known as landslip (USGSfactsheet, 2004), is a downward or outward movement of soil,
rock or vegetation, under the influence of gravity. This movement can occur in many ways. It can be a
fall, topple, slide, spread or flow. The speed of the movement may range from very slow to rapid.
(Kumari M, 2008). In mountainous areas, landslides are the second most destructive natural hazard after
earthquake. The economic loss and life loss due to landslides are increased considerably in the last
century, and most of the landslides are resultant from global climate change, such as El Niño and human
activities (Runqiu Huang, 2011). Landslide hazards may be single, sequential or combined in their origin
and effects and can be characterized by location, intensity or magnitude, frequency and probability
( (UNDRR, 2017)). Landslides contribute directly or indirectly to about 17% of all disaster-related
fatalities worldwide and rank as the 7th most killing natural hazard (Petley, 2012)

Since 1990, there have been over 10,700 disasters worldwide, affecting over 6 billion people. At global
level the landslide was affected 106,622 fatalities between 1980 and 2000 (World Bank, 2020).
According to the World Bank report (2005), 3.7 × 106 km2 of land surface is prone to landslides
worldwide, and nearly 300 million people live in areas of potential landslide risk (Maxx Dilley, Robert
S.Chen, Uwe Deichmann, 2005)). In the new millennium, landslides have claimed tens of thousands of
lives and an estimated annual average of economic losses of $20 billion, which is 17% of the total ($121
billion) yearly mean global disaster losses from 1980– 2013 (Martin Klose, Philipp Maurischat, Bodo
Damm, 2015).

According to the United Nations’ analysis (Roger Pulwarty, Rathana Peou Norbert-Munns, 2023), 346
disaster incidents occurred in 2015 and killed around 22,773 people. From the same disasters, 98.6
million people were affected, while USD 66.5 billion were economically lost and, among these disasters,
landslides alone affected 150,332 in 2015 and killed 4369 worldwide (Wubalem, 2021). In 2021, the
Emergency Event Database (EM-DAT) recorded 432 disastrous events related to natural hazards
worldwide. These accounted for 10,492 deaths, affected 101.8 million people and caused approximately
US$252.1 billion in economic losses (Roger Pulwarty, 2023).

International Disaster Database (EM-DAT) of the Centre for Research on the Epidemiology of Disasters
reported that landslides caused 17% of the deaths associated with natural hazards worldwide annually
(Kwan Ben Sim, 2022). Spatial distribution of fatal landslides reported according to the GFLD. Most of
the landslides are concentrated on Asia (75%), in regions such as the Himalayas, India, south-eastern
China, Iran, and neighboring countries of Bangladesh, Laos, Myanmar, Indonesia, and the Philippines;
in South America (8%), fatal landslides can be found along the Andes cordillera and Brazil, and in
Central and North America and the Caribbean (8%), along Costa Rica, Nicaragua, Honduras,
Guatemala, southern Mexico, and the
Caribbean islands; in Africa (5%), fatal landslides occurrences are concentrated in Tanzania, Burundi,
Kenya, Uganda, Rwanda, and the Democratic Republic of the Congo; and in Europe (3%) (Derly
Gómez, 2021).

Landslides not only result in casualties to both humans and animals but disrupt the water quality of
streams and rivers as well as the destruction of structural and infrastructural developments. Of the total
loss of life resulting from natural hazards worldwide, 5% of it comes from highly developed nations.
The remaining 95% of total deaths are from medium and developing countries (Nadim, 2012) (Klose,
Landslide impacts in Germany: A historical and socioeconomic perspective, 2026) reported that the
economic impact of landslides is likely the greatest on transportation infrastructures. This is especially
true in rural regions where the transportation network is scattered, and the availability of alternate routes
is few to none. As a result, a minor landslide will bring a great impact on the economic sector over an
extensive region (Mike G Winter, 2018).

In the East African highlands, landslides cause large-scale soil degradation and loss of assets,
infrastructure and human life (A. Knapen, 2006); (Pieter Vlaeminck, 2016); (Moeyersons, 2007)Yet the
remoteness of the affected areas and the small size of single events lead to serious underreporting of
landslides in these regions. This results in limited scientific attention and an underestimation of the
impact of landslides on human livelihoods and development
(MSILIMBA, 2012); (Jenna Jacob, 2015) The small scale and relatively diffuse character of most
landslides makes the assessment of their impacts a challenging issue (Petley D., 2012). In industrialized
countries most studies evaluate the impact of landslides by estimating the (potential) costs related to
direct damage of infrastructure or by estimating the foregone income for specific industries (Klose,
2015); (Klose, 2014). Qualitative case studies suggest that landslides in East Africa significantly affect
smallholder farmers’ income through the loss of houses, crops and soil fertility (Msilimba, 2009).

Rwanda is vulnerable to various natural hazards, including floods, earthquakes, windstorms, and
landslides, which cause loss of lives and have significant negative an impact on human development
properties, and infrastructures as well as the environment (MINEMA, 2022). It’s losing more fertile soils
to foreign water catchments within the Nile and Congo River catchments, where 15,000,000 tons are lost
on average every year. However, in Rwanda landside was prone to both natural disaster and man-made
disaster, Meteorological and Geological Disasters are natural disaster, and these man-made disasters are
caused by anthropogenic actives include pollution and traffic accidents.

According to MIDIMAR was reported from 2011 to 2013, 74 deaths, 22 injuries, 573 houses destroyed
or damaged, and 656 ha of affected land were recorded due to landslide. The most impacted is the
western province with more than half of the total deaths’ records (51%), followed by the northern
province (38%) of the total cases Districts Nyabihu, Rulindo, Burera and Karongi experienced more
deaths than others [national atlas of Rwanda). Ministry in Charge of Emergency Management was
reported from 2016 to 2018 the landslides triggered by heavy rain and flood were 93 fatalities, 39
injuries, 1362 houses damaged, 802.98 Ha crops and 128 Livestock (MINEMA, 2018).

In Rwanda, According Piller 2015 studied landslide using logistic regression with some environmental
factors such as slope, soil type, land cover and precipitation. Hence, the overall objective of the Rwanda
National Contingency Plan for floods and landslides is to support the timely, efficient, consistent and
coordinated response to anticipated floods and landslides in the rainy season, thus effectively reducing
the impacts on human population, livelihoods, lifelines, infrastructure and the environment. This will in
turn help reduce the scale of humanitarian needs to the affected population (MINEMA, 2018).

1.2 Problem statement

Worldwide, every year, landslides damage houses and cause millions of dollars’ damage to buildings,
roads, pipelines, agricultural land and crops with some causing injuries and loss of life (World Bank,
2023). In Rwanda, landslides dominate in areas of large mountain/hills in rain seasons between March-
May and from September-December because of heavy rainfall leads to soil saturation, as the soil is
unable to absorb the excess moisture brought on by the rain. Fault areas start cracking, the rivers
removing mud flow or loose materials through suspension and saltation due to material’s movement
from mountain top to bottom valley and other loaded material remained in mid of river as obstacle of
river flow and river water eroded on side of river and formation of new channel which prone to
landslides. High infiltration capacity of soil in rain season also causes the soil separated each other
which triggered to landslides. Natural steepest slope, soil properties and land cover change are main
factors that triggered landslide in Rwanda. In addition, overexploitation of resources and unplanned land
use such as deforestation, Poor agriculture mechanization and mining activities are considered to other
factors that causes landslide. Landslides result into casualties to both humans and animals, it also
disrupts the quality of water bodies as habitat, vegetation cover, natural landscape of earth surface and
wildlife as well as the destruction of structural and infrastructural developments. Hence the above
factors motivate us to make research of analyses impacts of landslides on environment.

1.3 General objectives

The overall objectives to analyses impact of landslides affected on environment and mitigation measures
in Rwanda. Table 1: Table of Specific objectives and Research questions.
Specific objectives Research Questions
To analyze Physical and human factors that Discuss the Physical and human facts that
triggered landslide in Rwanda triggered landslides in Rwanda?
To analysis negative impact of landslides affected Describe impact of landslides affected of the
of the Environment in Rwanda environment in Rwanda?
To identify strategies and mitigation measures to What are strategies and mitigation measures to
reduce the impact of landslides on environmental reduce the impact of landslides in Rwanda?
Chapter 2: Literature Review

2.1 History of Landslides on the world

Landslide is a major geological hazard, which poses serious threat to human population and various
infrastructures, the idea that it could occur is frightening people in every area prone to such phenomena.
This is because the effects of landslides can be devastating, leaving thousands of people without home
and threatening their lives. (Svalova, Landslide Risk Management and Crises Events, 2017). Landslides
can occur anywhere in the world and are more widespread than any other geological event. They occur
when large masses of soil, rocks or debris move down a slope due to a natural phenomenon or human
activity. Landslides can accompany heavy rains or follow droughts, earthquakes or volcanic eruptions
(WHO, 2019). Areas of steep terrain, land previously burned by wildfires, land that has been modified
due to human activities, channels along a stream or river are most vulnerable to landslides. Climate
change and rising temperatures are expected to trigger more landslides, especially in mountainous areas
with snow and ice (Napoli, 2020).

According to World Health Organization, between 1998-2017 worldwide, landslides affected an

estimated 4.8 million people and cause more than 18 000 deaths. Below are examples of deadliest
landslide in world’s history (Petrucci, 2022). China, the Haiyuan landslide, December16,1920 caused
200,000 deaths. Peru, the Yungay landslide, over 20,000 people were killed in May 1970, a massive
avalanche of ice, snow, and rock was triggered by an earthquake in the Andes Mountains, descended
into the valley below, buried the town under an estimated 300 feet of debris (FULLER, 1921). In Iran
the Manjil-Rudbar earthquake, April 10,1972 This earthquake triggered landslides that killed over 5,000
people with more than 10,000 injured. The landslides caused significant damage to buildings and
infrastructure, burying many people under the debris and making it difficult for rescue workers to reach
those in need. Colombia, the Armero tragedy, On November 13, 1985, the Nevado del Ruiz volcano
erupted, triggering a massive mudslide that buried the town of Armero, located at the base of the
volcano, killing over 23,000 people (Conchita, 2005).

In China

Since 2008 China earthquake landslides These landslides, triggered by the 2008 Sichuan earthquake,
killed over 18,000 people. One of the major impacts of the earthquake was the triggering of numerous
landslides in the area, which caused significant additional damage and loss of life (Sun, 2008).

In order to know this phenomenon better, and eventually protect themselves from its destructive action,
people should be aware of how landslides are formed and how they act. Depending on the location and
type of human activity, the landslide effect could be lessened. People should know hazard zones and
avoid activities in such areas (Svalova, 2017).

2.2 Types of landslides in Rwanda

Landslides are generally classified by type of movement (slides, flows, spread, topple or fall) and type
of material (rock, debris, or earth). Sometimes more than one type of movement occurs within a single
landslide, and because the temporal and spatial relationships of these movements are often complex,
their analysis often requires detailed interpretation of both landforms and geological sections or cores.
Different landslides occur in Rwanda; among them there are: rational slide, Translational slides, Block
slides, Rock fall, topples, lateral slide, debris flow, earth flow, mudslide, creep slide (USGS factsheet ,
2004). Rotational slide:

That’s slide in which the surface of rupture is curved concavely and the slide movement is roughly
rotational about axis that is parallel to the ground axis and transverse across the slide, the speed varies
from extremely slow to extremely rapid, the slope angle varies from 20-40 degrees (USGS factsheet,
2004).

Translational slide type

Mass move along a roughly planar surface with little rotation or backward tilting, speed varies from
extremely slow to extremely rapid speed (>5m/s), the slope angle varies from 20-45 degrees (USGS
factsheet, 2004).

Block slide type

Block slide is a translational slide in which the moving mass consists of a single unit that move down
slope as a relatively coherent mass (USGS factsheet, 2004)

Rock fall type

Rock fall Is the movement of materials such as rocks and boulders, they get detached from steep slopes
and cliffs. Separation occurs along discontinuity such as fractures, joints and bedding planes, movement
occur by freefall, bouncing and rolling. The speed of rock fall varies from rapid to extremely rapid; the
slope angle varies from 45-90 degrees (USGS factsheet, 2004).

Topple failures types

Distinguished by forward rotation of units about top point below end unit under the action of gravity and
forces exerted by adjacent cracks, the speed varies from extremely slow to extremely rapid and slope
angle varies from 45-90 degrees (USGS factsheet, 2004).

Lateral slide type

Usually occur on gentle slope or flat terrain, the dominant mode of movement is lateral extension across
shear fracture caused by liquefaction, sand and silts sediments turn into liquid state to flow, failure is
mainly triggered by rapid ground motion usually earthquakes (USGS factsheet, 2004).

Rotational slide type

Rotational is a form of rapid mass movement in which the combination of loose soil, rock, organic
matter and water mobilize as slurry that flow down slope. It is commonly caused by intense surface
water flow due to heavy rainfall they are nearly saturated and consist of silt and sand sized materials.
Debris flows are often associated with steep gallies.

Earth flow type

Occur in moderate to steep slope, when the top soils are overburden seasonally and saturated by heavy
rains. The material slides away from the upper part of the slope as crack to form bulge at toe (USGS
factsheet, 2004).

Mudflow type

Earth flow consisting of material that is wet enough to flow rapidly and contain at least 50% sand, silts
and clay particles. In many reports mudflow and debris flow are commonly referred to as mudslides, the
speed of mudflow varies from very rapid to extremely rapid(>5m/s) (USGS factsheet, 2004).

Creep type

Is a downward movement caused by shear stress sufficient to produce permanent deformation but too
small to produce shear failure, there exist three types of creep which are seasonal creep, continuous
creep, progressive creep (USGS factsheet, 2004).

Chapter 3. Research Methodology

This chapter contain study description, and methods of data collection technics both primary methods of
data collection and secondary data collection technics in order to getting information about landslides.
3.1 Study area description

The country of Rwanda is situated in central Africa immediately south of the equator between 1°4' and
2°51' south latitude and 28°63' and 30°54' east longitude. Its total area of 26,338 square kilometers is
bordered by Uganda to the north, Tanzania to the east, the Democratic Republic of the Congo to the
west, and Burundi to the south. Landlocked, Rwanda lies 1,200 kilometers from the Indian Ocean and
2,000 kilometers from the Atlantic Ocean (Mutabazi, 2011).

Rwanda forms part of the highlands of eastern and central Africa, with mountainous relief and an
average elevation of 1,700 meters. However, there are three distinct geographical regions. Western and
north-central Rwanda is made up of the mountains and foothills of the Congo-Nile Divide, the Virunga
volcano range, and the northern highlands. This region is characterized by rugged mountains intercut by
steep valleys, with elevations generally exceeding 2,000 meters. The Divide itself rises to 3,000 meters
at its highest point but is dwarfed by the volcano range, whose highest peak, Kalisimbi, reaches 4,507
meters. The Congo-Nile Divide slopes westward to Lake Kivu, which lies 1,460 meters above sea level
in the Rift Valley trough. In Rwanda’s center, mountainous terrain gives way to the rolling hills that give
the country its nickname,
“Land of a Thousand Hills.” Here the average elevation varies between 1,500 and 2,000 meters. This
area is also referred to as the central plateau (MIDIMAR, 2015). Further east lies a vast region known as
the eastern plateaus, where the hills level gradually into flat lowlands interspersed with a few hills and
lake-filled valleys. The elevation of this region generally falls below 1,500 meters. Administration of
Rwanda divided into 4 province and Kigali city. The province is divided into 30 districts. The districts
are divided into 416 sectors. The sectors divided into 2148cells and cells dived into 14837village
(Theoneste and Ntakirutimana, 2016).
3.2 Methods of data collection

In this subchapter containing the methods of data collections that were used for doing this research. We
were used both primary data collection and Secondary data collection. Those methods are likely
literature review, Field observation, library and flied visit.

Figure 1: Location map of Rwanda

3.2.1 Literature review and Library

In this research we were reading the books, Journal, magazine and new paper about the landslide in
Rwanda and all over the words. We were referring to previous reports of Government organization and
non-government organization. Same of national organization referring are MIDIMAR reports of
different years, MINEMA, REMA, Kigali city Publication documents and local government reports
document. The non-government reports are likely the following UN, EM-DAT, USAID and other non-
governmental organization. The purpose of this research is derived impacts of landslides in Rwanda.
The literature helps us clear design and referring other scholars what they said about landslides but for
compare as to day and proof and predict for how to reduce those negative impacts in future generation.
In this research comprise the statistical data from other authors that support for doing chart, graph in
order to make clear sense about landslide in Rwanda. Moreover, were reading online document, library
books and got more information about landslide like historical of landslide in worlds, influence of
landslide and impacts of landslide. In addition, how to prevent and measure taken for reducing landslide
impacts.
3.2.2 Field observation and field visits

Field observations are primary research method. In this research we were use both field observation and
field visit. For us in our day life we were walking for job in the morning and return in evening. We
looked place where landslides. This very import for us because we were getting more information about
landslides. In this research we visited the sample regions such as Muhanga District, Ngororero, Gatsibo
and Gakenke district that help us for taking photo for using this research. Field observation gives reality
which used for explaining clear about landslide impacts like road destroyed, houses destroyed, crops
destroyed and other infrastructure that damaged triggered by landslide disaster. Field observation gives
us the information of landslide’s impacts with infrastructure and environment which have high accuracy
and taking photo as proof of that realities.

Chapter 4. Result and discussion

This chapter focus on Physical and human factors that trigger landslides, types of landslides, negative
impacts of landslides and mitigation measures to reduce the landslide.

4.1. Physical and human factors that trigger landslides in Rwanda

4.1.1 Nature of slope to landslide in Rwanda

The areas of high slope are more vulnerable to landslide than areas of gentle slopes. In Rwanda three
parts of relief exist which are High land area, center Plateau and low land areas. The high land areas are
more affected with landslide compared to center plateau and lower land areas. An important factor in the
distribution of landslides is the slope gradient, mass movements occur only when a critical angle is
exceeded. Mostly in Rwanda, landslides occur on slopes as high as 14° which is the lowest in all the
studies. Most of Northern province in Rwanda are above 45 degrees of slope gradient, Western more
than 35o and Southern more than 25o. The Map bellow shows the areas that are more prone to landslide
in Rwanda.
Figure 2: Map that shows the Natural slope of Rwanda

4.1.2 Influence of soil properties in Rwanda

Soils in Rwanda have high clay content. High clay content in deeper soils may increase the water
holding capacity and give rise to long term progressive movement in certain cases and to more rapid
failure in extreme cases Rwanda natural hazards ministry in 2013 reported a landslide in Burera village
in North Rwanda, caused by over saturation of clay which led to the death of 8 family members. Soil
layers rich in clay in deep horizons are significant cause of the slumps in the western part of Rwanda.
Clay minerals result from the chemical weathering of silicate bearing rocks. In this research we were
conducted data from U-CGIS and made us map that show that the soil had clay between 20% and 35%
clay are more prone to landslide. The soil had above 35% clay are less prone to landside because this
resist for water penetration.

4.1.3. Undercutting of slopes in Rwanda

Rockslides resulting from human activities such as undercutting by roads or railroad excavations are
more widespread than rockslides resulting from natural causes (Nyamulında, 1989). Human activities
that involve undercutting disperse compact soil particles into loose particles thus reducing the soil
stability. Human activities that involve undercutting have a great impact on the stability of the area and
are seen as major factors causing slope failures in this century (Bizimana1, 2015). Slope undercutting
due to house construction and also foot paths cause concentrated flows which trigger landslides mostly
in the western part of Rwanda (Nyamulında, 1989). For examples the district more exposed to landslide
undercutting slope are likely:
Muhanga , Rulindo, Ngororero and Gakenke district are due to mining activities. Nyamasheke,

Musanze, Nyabihu and Rusizi are caused by human activities like agriculture. Landslide that’s
undercutting of slope are more vulnerable of an area in Northern province, Western province and
western parts of southern province. The Kigali city, the landslides are mostly provided by roads
construction and house construction. Eastern province is less vulnerable to landslide caused by
undercutting slope due to low land areas or gentle slope and small plain. This are a few in Gatsibo and
Ngoma district which have a few parts of low plain.

4.1.3 Period of heavy rainfall in Rwanda

Rwanda’s climatology differs strictly from its surroundings region in view of geomorphologic settings.
The climate is determined by the alternating moist south-westerly and dry north-easterly airstreams. The
mountain areas experience a bimodal rainfall pattern. The wettest period of the year is from March to
May, while the dry season occurs from July to August with a short dry period around January to
February and short wet season from September to December. Rainfall is higher at the Northern and
western slopes (1500- 3000 mm/yr) than at the eastern and Southern slopes (600- 1500 mm/yr).
Information from old rainfall data reveals that most areas in Rwanda receive an average rainfall of 800
mm. No extreme heat exists in the region due to its location (near the equator and altitudinal variations)
(Nzive, 2013). Climate can have a dramatic influence on mass wasting events. Heavy precipitation can
initiate certain types of mass wasting by creating hydrostatic pressure and serve to lubricate slides once
they are in motion and hence mostly results the mud flows. For examples the map is showing the areas
in Rwanda which are receiving high rain and low rain fall. The district which receive more rainfall are
the mostly more prone to landslides. The low land areas such as Eastern province are less prone to
landslides.
Figure 3: Map of rainfall pattern in Rwanda during 2019

Figure 4: Graph showing seasonal annual rainfall pattern in Karongi district during 1981 -2018
4.1.4 Influence of Land use/ Land cover change on landslide in Rwanda

Land use and land cover (LULC) are important conditioning factors that influence rainfall- triggered
landslides (Glade, 2003), studies have argued that land use/cover changes (LULCC) might increase
landslide susceptibility. Deforestation adds to landslides because the roots of trees and plants hold the
soil. On clearing the vegetation, the mountain slope loses its protective layer due to which the rain water
flows with very high speed on the slopes which results in landslides.

Figure 5: Map that shows the land use/ cover in Rwanda

4.2 Impact of landslides on Rwanda’s environment

In this research we were discussed about landslides impact on landscape of the earth surface,

Landslide impacts on Quality of rivers, streams and ground water flow, Landslide Impacts on

Drinking Water Quality and Environmental Health, Landslide Impacts on Forests and vegetation,

Landslide Impacts on Forests and vegetation and Social and economic impacts of Landslide in Rwanda

4.2.1 Landslide impacts on landscape of the earth’s surface in Rwanda

As reported in new times, more than 745 thousand Ha of agricultural land in Rwanda potentially loses its
topsoil every year this will increase in deformation of natural land behaviors (Nkurunziza, Rwanda loses
over Rwf 800bn annually due to soil erosion –new report, 2022). Slope gradient and slope curvature are
the main topographic factors that create susceptibility to landslide. Steeper gradients are generally more
prone to landslide although other geological climatic factors may also make gentler sloes susceptible to
failure. For example, slope facing a particular direction may be subjected to more intense storms.
Deeply-incised landforms and topographic depressions are also susceptible during rain storms. Slope
with blower gradients that have been altered by road construction are also more susceptible to sliding.
On natural slopes shallow landslides commonly occur at gradients of 15o-25o for earth flow and 20o-45o
for debris flows whether a slope steeper than 45 usually have sufficient soil to be vulnerable to sliding.
(Broadhead, 2013). For example, of areas that prone of landslide caused by steepest slope are in
Northern part of Rwanda like Gakenke, Rulindo and Musanze and Western region like Ngorerero,
Rubavu, Nyamasheke, Karongi and Rutsiro district defragmented formation natural surfaces areas. For
example, landslide was appearing in Karongi district in 2018

Figure 6: Photo that show landscape deformation due to landslide in Ngororero district
The land sliding appeared on Ngororero district which deformation of landscape

4.2.2. Landslide impacts on Quality of rivers, streams and ground water flow

Due to different agents some amounts of earth and organic materials should slide and enter streams as
sediments, thus will contribute in reducing the portability of the water and quality of habitat for fish
and wildlife. The main types of landslides that impact streams are debris flows, which may fill and/or
erode the stream channel for great distances. Debris flows provide important sediment transport links
between hill-slopes and alluvial channels (Butler, 2001), and thus are an important factor in drainage-
basin sediment budgets. In addition, debris flows influence the spatial and temporal distributions of
sediment in stream channels, either because they deposit sediment in the channels or because the
deposits provide a source for accelerated transport of sediment farther downstream (Benda, 1990). In
Rwanda Nyabarongo river and their stream was polluted because of landslide when the debris appear
in stream entering Nyabarongo it reduces the quality of river water. Nyabarongo water in regions of
mountains when flowing from top it eroded more material and high water absorption and the soil start
to move which triggered landslides. Landslide size and type play a role in impacts on streams.
Obviously the size of the landslide in relation to the size of the stream is important. Swanston (1991)
noted variable impacts to streams by different types of landslides. Some examples happened in this
year by April 28-29, where the North West and South West parts of Rwanda affected by heavy rainfall
that spread sedimentation in different streams and rivers like Nyabarongo, Sebeya, Santinsyi,
Mukungwa, etc, that affect directly the surrounding regions.

Figure 7: Phot shows that Landslide impacts on Quality of rivers, streams and ground water flow in
Nyabarongo tributaries in Muhanga district.
4.2.3 Landslide Impacts on Forests and vegetation

Forest destruction by landslide is common in many parts of the world, but particularly in tropical areas
where most part of our country covered. Its due to the combination of intense rainfall and earthquakes
in that area. Landslide and flooding in Rwanda not only destroy the built environment and biodiversity
but also badly erode soil that sustains crops. In Rwanda, landslide are obstacles to ecosystem like forest
cover and wetland areas which causing of decrease of forest. In Rwanda, the deforestation occurred both
rural areas and urban areas because of anthropogenic activities it’s provide the soil erosion. The
remaining forest or vegetation cover prone to landslide due to erosion. For example, in Gishwati forest
and more wetland in Rwanda were destroyed by landslide.

Figure 8: Photo show the Landslide Impacts on Forests and vegetation in Rubavu district

4.2.4 Landslide impacts on Habitats of natural wildlife that exist on earth surface or water.

The effect landslides have on animals are that landslides destroy their habitat and animals would have
trouble finding food since the landslide would have ruined their habitat and would have washed down
plants and bushes. If animals are around when a landslide is happening a large object could land on the
animal and kill it. When landslides occur plant life can be washed down the slope and it can also ruin or
destroy the plant life. It is the case in Rwanda where many plants and animals destruct to different
landslides happened years ago. In Rwanda, this case was Occurred in Gishwati were refuged due
landslide and erosion appear that lost the forest. In past time the Nyabarongo river and its tributaries
were appeared the more fishes on it but our day Nyabarongo river was lost those fish due polluted from
landslide.

4.3 Social and economic impacts of Landslide in Rwanda.

Landslides occur in Rwanda have different effects on people, buildings, animals and landscape. The
effects landslides have on humans are property damage, injury and even death. Water supplies, fisheries,
sewage disposals systems, forest and road ways can be damaged and affected. The table below are
reports published by MINEMA and MIDIMAR for landslide from 2016 to 2022.

Table 2: showing impacts of landslides on people and infrastructures

Source: From Nation disaster report of MIDIMAR and MINEMA from 20216 to 2022

4.3.1 Landslide causes the Deaths

The table above show that in 2016 the 112 people were die, 81 people were died in 2018, and 29 people
were died from 2019 to 2022. Those mortalities were caused by landslides due to different factors such
as poor housing, steepest slope and more rainfall.

4.3.1 Landslide causes the injured

According above table every year the people the lost the life and injured are appeared triggered by
landslides. From 2016 to 2022 the 118 people were injured due to landslide in Rwanda.
Figure 9: Effects of landslides on human. Source: Uwimana,2022

Figure 9: Photo that show injured caused by landslide

4.3.3 Landslide damage livelihood population

According to MIDIMAR and MINEMA reports every year more population were lost their shelter due to
landslides. From 2016 to 2022 more than 4 288 were damaged triggered by landslides.

Figure 10: Photo that show landslide damaged houses in Ngororo district. Source (Uwimana,2022)

Figure: Photo that show landslide damaged houses in Ngororo district

4.3.4. Landslides impacts the crops

Damage the crops. Landslide damaged crops in may region of Rwanda in rainfall season. More landslide
in Rwanda caused by rainfall. According to MIDAR, 2016 the landslides were damaged 4083 crops Ha.
According to MINEMA in 2018 the people were lost 392.28 crops due landslides. In 2019 the 392.28
crops Ha lost due to landslide. Rwanda is prone to landslide and more people vulnerable outcome of lost
their crops for examples from 2021 and 2022 according to MINEMA the 23.4 crops Ha. For instance,
the more population in Rwanda depend on agriculture actives when their lost the harvesting it affected
their living condition.

4.3.5. Landslide impacts on livestock

More than 80% Rwandan released on agriculture and livestock farming. The people of vulnerable of
impacts from landslides. The cattle needed the feeding from grasses when the landslide overcome on the
grasses and vegetation the animals depend on its got famine. Landslide also damaged the livestock
farming. For example, in Rubavu district the landslide fall on the cattle died exactly. In addition, hill
and mountainous regions in Rwanda mudflow, debris and rock fall was fall down on cattle and eroded it.
According to MIDIMAR 2016 the 824 of livestock were lost. And according to MINEMA from 2019 to
2022 the 866 livestock are lost due to landslide.

4.3.6 Landslide impacts on infrastructures like roads bridges, schools, churches, health center,
transmission line and water supply

According to above table data from MINIMA and MIDIMAR, every year the infrastructures such as
roads, schools, health center, churches, transmission line and water supply were destroyed and damaged
due landslides. From 2016 to 2022 the 197 infrastructures were destroyed by landslides in Rwanda.

4.4 The Strategies and mitigation measures to reduce landslides in Rwanda

4.4.1 Relocating people from high-risk areas

Some areas are known to being prone to landslide, it might also be possible that warning signs such as:
new cracks or unusual bulges in the ground, street pavements or sidewalks are visible before landslide
could occur, people should be evacuated earlier.

The highlands of the Congo-Nile Ridge in the Western, Southern and Northern Provinces are mostly
prone to landslide. About 40 percent of the country’s population, according to the atlas exposed by
MIDMAR in 2015, is also exposed to landslide at moderate to very high slope susceptibility. Gakenke,
Karongi, Muhanga, Ngororero, Nyamagabe Gicumbi, Nyamasheke, Nyaruguru, Rusizi and Rutsiro are
the likely disaster-prone districts.
Thus, the government has for years been involved in relocating families residing in these high-risk
zones, to identified safer places. Despite the big step in the relocation of families residing in these risky
areas, there are some families that are either still reluctant or have vehemently refused to heed the
repeated life-saving calls to relocate to secure places, putting their lives at stake.

Between December 2011 and September 2011, disasters produced a complex web of impacts, which
spans various sectors of the economy including loss of about 43 lives, 73 people were injured. Besides,
1854 houses were destroyed, 2, 989, 9 Ha of crops were damaged and eight school destroyed. In my
2023, At least 131people died while 18 thousand were displaced as entire villages engulfed. Beyond
6391homes, 17 roads, 2health center and 26bridges destroyed 58schools and 5power stations were
affected due to these hazards (Rwanda Broadcasting Agency). As a result, the cost of the intervention
activities in terms of disaster response and recovery to assist the victims wasn’t estimated until now, but
some families ware moved to another district where they were given shelter and support under the
START Fund for temporarily. The public are also considered as the country’s wealth and loss of any life
means loss of manpower and consequently wealth. Rwanda National Police, therefore, in its endeavors
to preserve and security for all appeals to those families that still live in the demarcated wetlands, hilly
or other areas considered high risk zones, abide by the country’s safety programmers, to voluntary
relocate to safe zones.

4.4.2 Reforestation and forest conservation practices

Reforestation and forest conservation are important means to combat the rapid soil erosion and
landslides that flow heavy rainfall. Reforestation is the process of restoring damaged forests or growing
forests on currently unfrosted land. There are several projects that inserted in this area for example in
Nyagatare, 13th November 2020. World Vision Rwanda, through its partnership with the Regreening
Africa and Forest Landscape Restoration (FLR) projects, has committed to plant a total of 7,695,300
trees throughout the 2020/21 tree-planting season to address climate change and improve livelihoods.

In line with the national theme for the tree-planting season, ‘Forests for Community Livelihood and
Sustainable Development’, and in an effort to contribute towards the Government’s target of planting 25
million trees this tree-planting season, World Vision organised a tree-planting event in Nyagatare
District to create awareness on the challenges of land degradation and the need for land restoration
initiatives.

The Regreening Africa Project (funded by the European Union – EU), and the FLR project

(Funded by the Australian Government through its Department of Foreign Affairs and Trade – DFAT)
and World Vision with technical support from World Agroforestry (ICRAF), together support farmers to
improve their livelihoods by providing improved food and nutritional security, climate resilience for
smallholder farmers and restored ecosystem services through evergreen agriculture - a form of
agroforestry where trees are incorporated onto crop and pasture lands.

Delegates from the Rwanda Forestry Authority, Nyagatare District, representatives from World Vision,
ICRAF, the Rwanda Agriculture Board (RAB) and other implementing partners joined residents and
farmers in Nyagatare District to plant several types of trees and other multipurpose agroforestry trees in
Gishuro IDP Model Village, Gishuro Cell, Tabagwe Sector. Present at the event was also Pascal
Zahonero, an EU delegate.

Last year, the Christian humanitarian organization through the two projects planted more than six
million tree seedlings whilst facilitating local community participatory approaches in tree seedlings
production, and providing capacity-building in various agroforestry and land restoration practices to
enhance agricultural productivity.

The trees will be planted in the districts of Gatsibo, Nyagatare, Kayonza and Bugesera in the eastern
province. The trees will include different species to address various household needs; including fruits,
fodder, soil fertility, firewood, erosion control and many others (World Vision commits to plant over 7
million trees through land restoration projects, 2020).

Figure 11:Reforestation practices in Ngorero District

4.4.3 REDUCING SLOPE STEEPNESS

Rwanda’s fertile lands are prone to soil erosion. An initiative to build terraces into hillsides is helping to
protect the landscape. Radical terraces are climate adaption strategy that deals with the adverse effects of
climate change manifested by heavy rainfall and causing soil erosion. These terraces provided in region
of steep hills like western & Northen parts of Rwanda (Rubavu, Nyaihu, Ngororero, Rutsiro, Karongi,
Musanze, Gicumbi,etc). Additionally, terraces are known to reduce water velocity, increase infiltration,
reduce nutrient depletion and increase in crop productivity. The radical terraces allow the farmers to
resist and adapt to climatic change, generate income and enhance food security.

Figure 12: Photo taken in Western province, Rubavu District under sebeya landscape restoration pilot
program.

4.4.4 STORM WATER DRAINAGE SYSTEM

Storm water is surface water in abnormal quantities resulting from heavy falls of rain. The floods are
usually triggered by poor drainage systems. To control it we have to provide a plan for draining for each
area, the storm water master plan could help develop centralized drainage systems. For example, over $1
million (over Rwf1 billion) is set to be invested in developing the Kigali 'Storm water Management
Master Plan' that is expected to be complete by 2024 so as to mitigate floods in the city. The Kigali
Storm water master plan is the plan which shows how the city will be able to manage floods by
improving the drainage system (Nkurunziza, Kigali to Get Storm Water Master Plan in Two Years,
2022).
Figure 13: Rain runs into the storm water system

4.4.5 REDUCING SLOPE STEEPNESS

Rwanda’s fertile lands are prone to soil erosion. An initiative to build terraces into hillsides is helping to
protect the landscape. Radical terraces are climate adaption strategy that deals with the adverse effects of
climate change manifested by heavy rainfall and causing soil erosion. These terraces provided in region
of steep hills like western & Northern parts of Rwanda (Rubavu, Nyaihu, Ngororero, Rutsiro, Karongi,
Musanze, Gicumbi,etc). Additionally, terraces are known to reduce water velocity, increase infiltration,
reduce nutrient depletion and increase in crop productivity. The radical terraces allow the farmers to
resist and adapt to climatic change, generate income and enhance food security.

Figure 14: Photo taken in Western province, Rubavu District under sebeya landscape restoration pilot
program.
Conclusion

This review has examined the multifaceted environmental impacts of landslides in Rwanda, a country
particularly vulnerable due to its unique geographical and climatic conditions. The analysis has
highlighted the complex interplay of physical factors, such as steep slopes, soil properties, and heavy
rainfall, with human-induced factors like deforestation, unplanned land use, and undercutting, in
triggering these devastating events. The review has further explored the significant environmental
consequences of landslides, including landscape deformation, water quality degradation, forest and
vegetation destruction, and habitat disruption. These environmental impacts have cascading effects on the
social and economic well-being of communities in Rwanda, underscoring the urgent need for effective
mitigation strategies.

The review has demonstrated that landslides are not merely natural occurrences but are significantly
influenced by human activities. Therefore, effective mitigation must address both the natural and
anthropogenic drivers. This includes promoting sustainable land management practices, such as
reforestation and controlled development, improving infrastructure planning to avoid slope undercutting,
and implementing early warning systems to enhance community preparedness. Furthermore, raising
public awareness about landslide risks and promoting community participation in disaster risk reduction
efforts are crucial for building resilience. Further research focusing on specific landslide hotspots,
integrating local knowledge with scientific data, and evaluating the effectiveness of different mitigation
strategies is essential to develop comprehensive and sustainable solutions for landslide risk reduction in
Rwanda. By understanding the complex dynamics of landslides and implementing proactive measures,
Rwanda can minimize the environmental damage and build a more resilient future for its communities.
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