TACKLING THE LANDSLIDE PROBLEM IN LA PAZ, BOLIVIA THROUGH INTEGRATED ANALYSIS

1

T

ACKLING THE LANDSLIDE PROBLEM IN

L

A

P

AZ

,

B

OLIVIA THROUGH INTEGRATED ANALYSIS

Landslides caused by heavy rains crashed down onto poor neighbourhoods in the Bolivian city of La Paz, destroying some 4000 homes, 2011, BBC news http://www.bbc.co.uk/news/world-latin-america-12594585 Milan de Blok Earth Sciences 10646477 Laura van Wetering Human Geography 10555676 Reinout Priesterbach Business Sciences 10649662 Stijn Eekhof Economics 10683828 Expert: Kenneth Rijsdijk Tutor: Tamara Jonkman Date: 23 November 2015 Words: 6797

2

A

BSTRACT

The highest located capital city in the world, La Paz, Bolivia, is struggling with the ever present threat of landslides. Many people in La Paz now live in areas that are highly vulnerable to landslides, but not much seems to be done to avert possible disastrous scenarios. In this paper, an integration of knowledge from four different disciplines is presented, with the intention of attacking the problem at its core. Physical, social, business and economical factors play not only a role in constituting, but also in mitigating the threat. Each discipline proposes a set of theories that helps create understanding in different ways. These theories subsequently give chance to find suitable mitigation measures that have the purpose of creating a less vulnerable and lower risk environment in La Paz. The integration of knowledge and insights finally accomplish a sturdy framework and set of mitigation measures that tackles the landslide problem in La Paz, Bolivia.

3

T

ABLE OF CONTENTS

Abstract ... 2 Table of contents ... 3 Introduction ... 4 Methodology ... 5 Theoretical Framework ... 6 Earth Sciences ... 6 The Internal slope balance-theory ... 6 The Poly Causal phenomena-theory ... 6 The disaster prevention- theory ... 6 Human Geography ... 7 Urbanization, population growth and poverty ... 7 Overloading by land-use change ... 7 Poly Causal Phenomena-theory ... 7 Business Studies ... 8 Framing ... 8 Economics ... 9 Results ... 11 Hazard ... 11 The internal slope stability ... 11 The Poly Causal Phenomena Theory ... 12 Awareness ... 14 Elements at Risk ... 15 Vulnerability ... 16 Poverty reduction ... 18 Risk assessment ... 19 Concept Map ... 21 Optional Mitigation Measures ... 22 Conclusions and Recommendations ... 23 The Landslide mitigation framework ... 23 Literature ... 24

4 Figure SEQ Figure \* ARABIC 1 - Results of the 2011 Pampahasi landslide

I

NTRODUCTION

The city of La Paz is situated in the west of Bolivia at an elevation of approximately 3,600m. It is considered to be the geographically highest located capital city in the world. Because of its mountainous surroundings, La Paz is a city where landslide frequently occurs. Over 100 landslides have occurred in La Paz and adjacent areas since the start of the twentieth century (Roberts et al. 2014). These landslides, which are defined as all types of mass movement of soil material down a slope (Alimohammadlou et al., 2013), are responsible for the loss of numerous lives, private property and infrastructure. The severity of La Paz’ vulnerability to landslide events became even more apparent in 2011, when the Pampahasi Landslide affected an area of 2 km2

and necessitated the

evacuation of up to 6000 people. 300.000 people had no access to running water for months after the landslide, and many of the displaced people are still living in temporary shelters. The causes of this landslide event, which was the

most severe in at least 400 years, have mostly been assigned to bad land use management. However, landsides cannot all be prevented, and the vulnerability of the city has increased due to the rapid urbanization and population growth of the city (Roberts et al. 2014).

These landslide events have had large consequences for both the development of the region and the quality of life. Also the need for better

mitigation measures has become increasingly apparent. The 2011 Pampahasi landslide demonstrated the multiplicity of factors contributing to landslide risk, and the only way to reduce these risks is by an integrated analysis of different fields of study. Therefore, this paper aims at finding mitigation measures from an interdisciplinary point of view. By integrating theories from different disciplines, a more holistic set of recommendations can be made. Proper management on a geological, anthropological, economic, and governance level can reduce both the risks of landslide events as well as the threat of these events. This paper creates an understanding of the natural causes of landslides, and consequently about the anthropogenic stimulating factors. The research question of this paper is: “How can an integrated view from the perspective of earth sciences, economics,

business studies and human geography contribute to mitigation measures to the hazard of landslides in La Paz, Bolivia?”

This will be done by integrating theories and concepts, found in the fields of earth sciences, human geography, business studies and economics, into a holistic framework that considers both natural and anthropogenic stimuli of landslides. In the first chapter, a theoretical framework will be provide, which is based on each of the disciplines. These theories will lead to results relevant to the case of La Paz and will be provided in the second chapter. Consequently, an integrated set of recommendations to the government as well as the society will be made. The third chapter visualizes

5

this integrated set of findings in a concept map. The conclusions of this study will be presented in the last chapter.

M

ETHODOLOGY

The main question that is stated above is mainly answered by performing literature research. Literature provided with many insights and theories that are concerned with the landslide hazards in La Paz. In the following chapter, a theoretical framework puts all knowledge derived from literature into a structured order. Combining this knowledge is where most useful conclusions are formulated. The literature research for Earth Sciences gathers knowledge about the physical processes that cause landslides, whereas Human Geography provides with knowledge about the social factors that amplify the landslide hazards. Next, knowledge from the discipline of business sciences connects to this by putting forward a marketing theory that plays a big role in long-term prevention of the problem. Knowledge from the discipline of Economics creates insight into the economic quantification of this landslide hazard.

Regular meetings offered chances to integrate all knowledge and create common ground. In this paper, integration plays a big role in coming to a conclusion. The conclusion can in this way be most

6

T

HEORETICAL

F

RAMEWORK

E

ARTH

S

CIENCES

For the discipline of Earth Sciences, there are three main theories that underlie this research. These theories are the Internal slope balance-theory, Poly Causal phenomena-theory and the disaster prevention theory.

T

HE

I

NTERNAL SLOPE BALANCE

-

THEORY

The article ‘Landslide process and impacts: A proposed classification method’ by Alimohammadlou et al, 2013, proposes a clarifying view on the physical properties of slopes. This theory is built on the physical laws of gravity, motion and equilibrium. This theory enables scientists to observe a slope in a systematic way. It states that there is a loose layer of soil present on the slope, and that this layer of soil is subject to two main forces; a gravitational force that pushes the soil layer down the slope, and a restraining force that keeps the soil layer in place; the soil restraining parameters. In this perspective, the threat of a landslide can easily be explained through a mathematical equation. When Gravitational forces > Soil restraining forces, movement of the soil layer down the slope is induced. This method offers opportunities for engineers to calculate the stability of a slope, quantify threats, and the quantitative effects of technical mitigation measures.

T

HE

P

OLY

C

AUSAL PHENOMENA

-

THEORY

This theory poses a more integrated perspective on the causes of landslides. The authors have assigned the label poly causal phenomena theory, but the term ‘naturally-human induced natural

hazards’ is present in publications of the last fifteen years. This theory is used to understand and

emphasize the relationship between the human- and the natural world. It states that these worlds are not separate systems, but an integrated dynamic environment with large influences on each other (Alimohammadlou et al., 2013).

The polycausal phenomena theory literally means that these events are caused by many different factors. These factors are dividable into natural and anthropogenic causes or stimuli. At first, it is important to give a clear definition of the concept of landslides: ‘Landslides are all types of mass

movements down a slope which can consist of soil, rock, debris, organic matter, artificial fill, or a combination of these’ (Alimohammadlou et al., 2013). Furthermore, it is important to define the

different stimuli belonging to the two categories of both natural- and anthropogenic causes. It has to be noted that there are types of natural disasters, which originate from the endogenic processes within the earth, of which the inducement of these is purely natural. Societal processes such as urban expansion and population growth often enlarge the impact of these events.

T

HE DISASTER PREVENTION

-

THEORY

This theory states that natural disasters are increasing in both frequency and impact. This theory is more of a relevance-enlarging theory than a theory that can be used during the analysis of the problem and the integration of different techniques. However, it is worth mentioning in regard to the case study of La Paz, Bolivia. As stated in their article, Huppert and Sparks state: ‘Only through

7 preparedness and resilience, it is possible to reduce the hazard of natural hazards’ (Huppert & Sparks, 2006). This quote clearly indicates the relevance of this research.

H

UMAN

G

EOGRAPHY

In the discipline of Human Geography there are two major theories that are of importance to the research: urbanization and land-use change. The concept of population growth will be introduced in combination with the urbanization theory. After that, the scope will shift towards the inequalities of income and its influence on the settlement of citizens and their vulnerability to the effects of landslides. Finally, the scope will shift towards the poly causal phenomena theory and the anthropogenic causes.

U

RBANIZATION

,

POPULATION GROWTH AND POVERTY

Urbanization and population growth are two concepts that are well known, both implying a change in the population (size and place). These changes can, for example, be an increase in population due to more births, or the expansion of the area where a population lives due to a shortage of housing for the population in the original settlement. Another change one can think of can be the migration from rural areas to urban areas because of several reasons, such as for example work or family related issues. For the first time in history more people live in urban areas than in rural areas (Huppert & Sparks, 2006). This change from rural to urban makes communities living in these urban areas much more vulnerable when it comes to natural hazards (Huppert & Sparks, 2006). This is because people in cities live in close proximity to one another in areas that are already of high risk. If a landslide occurs more people will be affected. Due to rapid urbanization and population growth, human activities in reforming and adjusting the landscape to their needs will increase to meet the demand of the growing population.

O

VERLOADING BY LAND

-

USE CHANGE

In combination with urbanization, the concept of overloading (placing excessive load on slopes) has great implications when looking at landslides.

An example for the overloading of a slope is the installation of residential infrastructure (Alimohammadlou et al. 2013). In combination with this residential infrastructure, Alimohammadlou et al. (2013) mention various concepts such as land-use change and industrialization in relation to overloading. A form of land-use change that they mention is deforestation, so that houses can be built to meet the demand for housing.

Another important concept is industrialization, which is linked to the concept of land-use change, because in order to increase industrialization, land-use change is needed. Also, industrialization is focused on the long term, meaning it can have long-lasting influence on the environment. Industrialization is linked to potential changing weather patterns on the long term, which can result in a greater landslide frequency or intensity (Alimohammadlou et al. 2013).

P

OLY

C

AUSAL

P

HENOMENA

-

THEORY

As mentioned in the section of earth sciences, the poly causal phenomena-theory is used to understand and emphasize the relationship between the human- and the natural world and it states that these worlds are not separate systems, but an integrated dynamic environment with large

8

influences on each other (Alimohammadlou et al., 2013). In the paper “Extreme events due to human-induced climate change” by Mitchell et al. (2006), the authors discuss that climate change is induced by humans, by the emission of large amounts of CO2, and that this will affect extreme

weather events in the (near) future. In this case, not the CO2 emissions, but the growing population

will influence the landslides in La Paz. As mentioned before, due to rapid population growth and a growing demand for housing, housing is scarce, which results in self-built settlements, and puts pressure on the unstable slopes surrounding La Paz (O'Hare & Rivas, 2005). This is an example of a human-induced natural hazard. The earth sciences part mentions how different forces ‘create’ a landslide, which is related to the influence of human behaviour, and in this case the building of houses, which enlarges the effect of landslides.

B

USINESS

S

TUDIES

After discussion and literature research it has become clear that creation of awareness in the hazardous area is an important part of the mitigation process. Through communication, awareness can be created. In the first place the government of La Paz can be held responsible for communicating essential information about the landslide hazards in order to create awareness among their citizens. Since the government will deal with different classes among the community, a way of communicating must be chosen in which they can be informed to the utmost extent. The community of La Paz is not a small one, with its 1.7 million citizens. In this chapter a key theory called the "framing theory" will be explained and put to discussion, to clarify how it can supposedly be of vital contribution to reaching the goals of awareness creation among the citizens. Creation of awareness already addresses a big part of the mitigation process through changes of incentives of individuals.

F

RAMING

The framing concept emerged in 1972. Gregory Bateson then first used it in his book "Steps to an Ecology of Mind". He defined a frame as being a "spatial and temporal bonding of a set of interactive messages". In 1974, Erving Goffman used the concept under the title of "frame analysis". In his article, Goffman stated that people interpret surrounding occurrences through their primary framework. This is the framework that is deemed by the individual. The framing theory suggests that the way people process information is influenced by how it is presented (the frame) to an audience. (Goffman E., 1974)

The theory is related to the "agenda-setting theory". Rather than focusing on a particular topic, framing focuses on the main concerns at hand. The basis of it is that media may focus on a certain event and places it within a field of meaning, thereby influencing the processing of information. The main reason for the concept having expanded to organizations, which use media as a tool for advertising, is that it can have a big influence. (Scheufele, 1999)

News or media are the most common users of framing, as they place a frame on all information that they convey. These frames are thought to influence the audience's perception of the given news. They make things easier to believe, more interesting and enable the media to get a grip on its "customers". Other than agenda-setting, framing also tells this audience how to think about the given issue. This is also referred to as second level agenda-setting. (Fairhurst & Sarr 1996)

9

Chong and Druckman (2007) distinguish two types of frames: equivalency frames and emphasis frames. Equivalence frames offer phrases that cause individuals to alter their preferences. These frames are most often expressed in gains versus losses. To further explain this, Kahneman and Tversky (1984) studied how subjects change their reaction to given choices if the questionnaire is framed positively instead of negatively. They came to the conclusion that when a frame is based on potential gains, people tend to choose a less risky option. Vice versa, when faced with potential losses, people tend to choose the riskier option. Emphasis frames, in this case less relevant, offer phrases that cause individuals to make judgments. In terms of gains and losses, an equivalency frame suits this case better. Individuals in La Paz will be confronted with information about a hazard that could lead to losses, and the framing of this hazard will influence the choices people make.

E

CONOMICS

To make an assessment of the magnitude of economic damage, a framework is needed by which this will be calculated. Therefore, it is necessary to further define what a landslide risk is exactly and how materialistic damage influences this. The assessment of how different factors influence the magnitude of a risk is done by the following formula: R = H × E × V Where:

● R is Risk, referring to the expected number of lives lost, persons injured and damage to property or disruption of economic activity due to a particular event.

● H is Natural hazard, defined as the probability of occurrence of a potentially damaging event within a specified time and given area.

● E is Elements at risk, including population, buildings and engineering structures, infrastructure areas and lines, public service utilities and economic activities.

● V is Vulnerability related to the (potential) results from event occurrence expressed with qualitative, semi-quantitative or quantitative methods in terms of loss, disadvantage or gain, damage, injury or loss of life (Papathoma-Köhle et al., 2007). According to Glade et al. (2006), this theory first came up in 1980 and was published by the office of the United Nations relief coordinator (UNDRO). The theory was the result of an expert group meeting of scientists specialized in natural hazards and had the goal of providing further guidance on defining concepts of vulnerability analysis and applying these to practical physical planning (UNDRO, 1980). The concept has been transferred to landslide issues by numerous authors and has since then been the theoretical framework for various case studies on landslide risk (Glade et al., 2006). Although this theory is a simplification by only taking three elements into account, it is very useful to identify the principal factors attributing to the magnitude of a risk. In the field of landslide research, risk is often only defined as the probability of the occurrence and is reviewed from an earth scientific point of

10 view for hazard mapping (Papathoma-Köhle et al., 2007). However, this formula indicates that the elements at risk and the vulnerability to the potential results are also contributing to the concept of risk and leaving out these elements might underestimate the dynamic role of the factors causing the problem (Glade et al., 2006). Another important factor to this formula is that the different terms are not added up but multiplied. Although this does not make much sense mathematically because it is not possible to quantify the different elements, it is significant because if either one is zero, the total risk will be zero. For instance if there are no elements at risk because the structural vulnerability is very low, the risk is zero even if the hazard exists (Glade et al., 2006). This formula can now be used to make an indication of the economic damage to landslides by firstly identifying the elements that are at risk in La Paz and secondly by clarifying what the vulnerability to landslides is of these elements.

11

R

ESULTS

In this section the results of this research will be further elaborated. The results will be structured following the earlier mentioned formula; 𝑅 = 𝐻 × 𝐸 × 𝑉

H

AZARD

T

HE INTERNAL SLOPE STABILITY

As discussed in the theoretical framework, the forces present on a slope can be divided into gravitational forces and soil-restraining forces. These forces are net forces, consisting of several factors, which will now be identified. Gravitational forces/motion inducing forces Soil-restraining forces Force of gravity Friction of soil layer Soil saturation → friction reduction Cohesion of soil molecules Precipitation increasing mass Plant roots We can state that precipitation is the most unpredictable force that is present. Because of its variability it is difficult to take measures that can ensure the stability of slopes. Furthermore, the flowing water of rivers and water flowing directly on the slope surface erode the slope, and decrease the stability. In the figure below, the soil layer is represented as a symmetric block, but of course in practice the shapes of these slopes are often far from symmetric.

Figure 2 - Forces acting on the soil of a slope

Although this figure is a simplification, it clearly shows the gravitational forces present on slopes. One final characteristic of water in slopes is the hydration of soil molecules. In certain mineral types, water molecules can form a hydration shell, which significantly reduces the frictional forces between these molecules. When a molecule becomes hydrated, it is enclosed in a circle of water molecules. The hydration impedes the soil molecules to interact with each other through electrical charge, which results in a reduced friction between these molecules (Christopherson, 2015).

12

T

HE

P

OLY

C

AUSAL

P

HENOMENA

T

HEORY

In this section, only the natural causes of landslides will be taken into account. The anthropogenic causes will be dealt with in the section of Human Geography. A selection of natural causes for landslides is given in the table below.

Precipitation – precipitation increases the weight per volume of the soil, which increases the gravitational force. Furthermore it has eroding forces. Eroding of the bottom slope changes the centre of gravity. Thirdly, it reduces the internal cohesion of soil material, which reduces the internal friction of soil layers. Climate change - it is debatable whether climate change is a natural or anthropogenic cause, but certain is that precipitation rates increase. The intensity of rainfall increases together with the total quantity. This can have severe effects on the slope stability (Huppert & Sparks, 2006). Erosion – erosion is the gradual disintegration of soil materials through natural forces such as water, wind and ice. The movement of water in or through the soil is the main erosional process regarding the La Paz case study. When the bottom of a slope is eroded, the centre of gravity changes towards the bottom of the slope. The gravitational forces increase, which means that the movement inducing forces increase and thus the chances of a landslide event increase. Weathering - both chemical and physical weathering can occur. It changes the chemical (and often also the physical) properties of the soil. For chemical weathering to occur, enough water has to be present in the environment. In La Paz, there is sufficient water during the wet season, which lasts from October until March. In the figure below, the precipitation data has been visualised. Physical weathering occurs by physical processes in the earths’ environment such as pressure, temperature, and forces by plant roots or by freeze/thaw action. It slowly breaks down the rock structures, which reduces the stability of the materials and thus the stability of the slope as a whole. Endogenic processes - endogenic processes such as earthquakes and volcanic eruptions have such enormous power that they can induce a landslide, provided that the circumstances are suitable. Logically, there has to be a slope present, and this slope has to be destabilised up to a certain level. The requirement is that the landslide inducing forces outweigh the soil-restraining forces. When the force is large enough to reach this threshold, movement can be induced.

13 Figure 3 - precipitation data La Paz (1 inch is 25.4 millimetres) Next to the natural side of this theory there is also an anthropogenic side. The anthropogenic part of this theory focuses, as mentioned earlier, on the fact that extreme events, such as landslides, can be induced by human intervention. The intensity of landslides in La Paz can be lowered if humans change their habits.

Since the 1900’s there is a steadily increasing stream of migrants flowing into the city of La Paz, looking for work (Leonard, 1948). In 1952 Bolivia underwent significant changes during the National Revolution, such as agricultural reforms (Heins, 2011). A goal of these agricultural reforms was to initiate settlement processes and start a “march to the east”, because of high population density in the west (Heins, 2011). These reforms had little success. Another effect of this National Revolution is the migratory movement, also from indigenous migrants, into the cities, because people continued to believe that they would find work in the city and they would have a “better life” (Heins, 2011). A combination of rapid urbanization and population growth due to the incoming flow of unemployed job-seeking migrants puts enormous pressure on the housing sector and increases the number of unemployed citizens. These citizens have no income, and thus poverty rises in the city of La Paz. When looking at Bolivia as a whole, monetary poverty is concentrated in the valleys and the western and central highlands, which include La Paz (Arias & Robles, n.d.). It is also important to focus on land use change, such as for example deforestation. Deforestation has negative effects both in the short- and the long term. The removal of tree canopy results in loss of interception of precipitation, and loss of evapotranspiration. This promotes wetter and less secure slope from the moment the tree has been removed. In the long term the decay of roots gradually decreases the stability of slopes. After complete degradation of the roots, a pipe may remain that can lead to intensified internal and seepage erosion (Brown & Sheu, 1975). Another example is to make room for housing. The already unstable slopes surrounding La Paz become more vulnerable when combined with population growth and urbanization, resulting in self-built settlements being

14

created on the slopes (O'Hare & Rivas, 2005). These self-built settlements lack stable foundations, resulting in unstable houses on unstable slopes. This will result in a higher chance of landslide occurrence. Changing weather patterns, such as higher precipitation rates, are dangerous for La Paz because of the steep hill slopes in combination with the rivers surrounding La Paz. Therefore land-use change needs to be reduced.

A

WARENESS

At this moment, most mitigation efforts for landslide hazards in La Paz seem to concern mostly short term mitigation and reactions to landslides, which do not really tackle the problem at its core (UN/ISDR 2007), ; only little effort is put into finding/communicating suitable ways of long term prevention, which in this research is believed to be the "real" kind of mitigation. The government has to take a greater form of responsibility in reaching out to their citizens to communicate their way to a well-prepared and resilient community.

The need of a government to get its message across to their citizens can be related to mass communication which is seen in the science of marketing. Mass communication it is all about trying to find the right way to present a certain piece of information in order to reach a large audience and make the people respond to that message the way that was intended (Keller & Kotler 2012). One can see the government as the business and the citizens as their customers. Instead of wanting to make a profit in the form of money however, the goal in this situation is to make a common profit in the form of awareness and therewith preparedness among the population of La Paz. Advertising is an important part of mass communication. It is mainly seen in the form of advertising campaigns. The purpose will be to educate people in order to influence behavior. Through advertising this can be done in a very cost effective way. Especially in a country that does not have a very strong financial position, advertising is most appropriate. "An advertising objective is a specific communications task and achievement level to be accomplished with a specific audience in a specific period of time"(Colley 1961).

The advertising objective of the government will be to inform and remind. Generally, the government will want to decide on what that objective is specifically. For instance, the advertising objective could be: To increase among 1.750.000 citizens, who are in danger of landslides, the number of people that identifies landslide mitigation as an activity of great importance from 15 percent to 50 percent in one year. Accordingly, a message has to be created and evaluated, a vehicle of advertising has to be chosen (radio, TV, magazines, billboards etc.), timing and allocation of resources has to be decided upon, and finally the results have to be evaluated. All of this has to do with the kind of frame one chooses to carry out information. In the end, the frame will determine the effectiveness of all efforts put into communication.

As mentioned earlier, focusing on building an equivalency frame is the most logical option in this case. The city of La Paz is concerned with a great threat that could lead to great losses. When connecting this to the gain based frame that was explained earlier on, the following (exaggerated) scenario can be put forward: A landslide "could" strike after the following year, potentially killing half

15

of La Paz' citizens. Response A to this could be to start behaving differently with such effort that when a landslide strikes, 75% of the people are saved by all means. Response B could be not to do anything differently (no discomforting efforts), but with the risk that half of the population is not saved when a landslide actually occurs. By theory, as Kahneman and Tversky (1984) demonstrated in their research, most respondents in this case will tend to choose the less risky (preferable) first option. The scope here is to confront all concerned parties with a dilemma that is related to the landslide hazard, not to sow fear, but to let people come to a rational decision based on awareness of the present threat.

E

LEMENTS AT

R

ISK

In this part, a description will be given of the elements that are at risk of landslide events. This concerns both population and material elements.

As mentioned in the theoretical framework; urbanization, population growth and poverty are closely linked to each other. Due to rapid population growth (migrants and natural growth) more and more citizens are looking for work in the city of La Paz, and this puts enormous pressure on multiple sectors, such as the housing sector (Leonard, 1948). All these people need jobs to provide themselves with the basic necessities, which may not be possible in the current market. This influences the poverty rate in the city of La Paz.

Figure 4 - Incidence and intensity of consumption poverty in Bolivia, 2001. Source: Arias, O. & Robles, M. (n.d.). The Geography of Monetary Poverty in Bolivia. Circled in red is the municipality of La Paz

The department of La Paz presents one of the highest levels of poverty in Bolivia (Arias & Rovles,

n.d.).The municipality of La Paz is situated in the red oval in the figure above (Figure 3). On this map

it is visible that the lighter part in the municipality is the city of La Paz, encircled in blue. Here, the poverty lies between 25 and 50%. In the areas surrounding the capital the poverty rises over 50%, and even above 75%. A great difference can be seen between the richer part of the city and the

16

municipality (the capital), which is light green, and the poor part of the municipality and the city, which is dark green and surrounding the capital and on the slopes in the capital. When looking at the city of La Paz, the poorer people settle on the slopes of the city and take responsibility for the organization and construction of their homes themselves (O’Hare & Rivas, 2005), because of the lack of sufficient income to buy a house or property. Due to the rapid population growth in La Paz, standard housing is so scarce that settlement in these self-built homes is necessary; and about 60% of the population of La Paz crowd in these settlements ((O’Hare & Rivas, 2005). The downside of these self-built homes is that they are not very stable and the people that live in these settlements are exposed to a very high risk of natural hazards, such as landslides (Nathan, 2008). The poly causal phenomena theory, mentioned earlier in the theoretical framework, is applicable here; because it becomes apparent that the settlement of citizens on unstable slopes surrounding La Paz can amplify the impact of landslides. The combination of building unstable homes and the already unstable soil of the slopes is dangerous. These two actions reinforce each other and can therefore cause a greater intensity, and maybe also frequency, of landslides.

The first and most important element at risk from an economic perspective is the housing sector. Material damage can be caused by the total collapse of houses, partial collapsing or minor damage that can more easily be fixed. The damage to the housing sector has caused major rebuilding costs in urban areas, but also inflicts economic costs indirectly by, for instance, evacuation measures (Alimohammadlou et al. 2013). An important feature of the housing sector in La Paz is that the location is mostly divided by social class. Most of the low income parts of the community are based in the periphery of the city on steeper gradients where the landslide risk is higher. Middle and upper class buildings are located in the centre of the city where they are less vulnerable to landslides (O’Hare, 2005). Important structural features of the housing sector in the more hazardous areas are the self-built settlements. Because standard housing is too scarce, and even the least expensive houses are above the financial limits of the low-income families, vacant land in the south of the city has been used by thousands of families to build self-made settlements resulting in a high population density. In these areas, there is no regulation to buildings, and houses are often made with sub-standard materials and designs. In 1992, it was determined that up to 40% of the population in La Paz lives in houses that are either of poor quality materials or of improper design and up to 60% lives in self-built houses (O’Hare, 2005). It can be concluded that the elements at risk of landslide occurrences in the housing sector are largely determined by social class.

Another element that is at risk is the local infrastructure. Landslide activity often results in large damage to the infrastructure. The collapse of roads and bridges result in government spending to rebuild these roads (Alimohammadlou et al. 2013).

V

ULNERABILITY

As stated before, Vulnerability is described as the potential results of a landslide event. This can be further described by looking at the social aspect: potential injury or loss of life in the affected areas is determined by the social vulnerability of the affected population (Papathoma-Köhle et al., 2007). The Elements at risk chapter provided more insight in the economic situation of La Paz, where self-built settlements and the social class of inhabit is an important feature. Therefore, it is necessary to further describe the trends in economic distribution.

17

The aforementioned migration to urban areas has had measurable effects on the poverty levels in Bolivia. The study of O’Hare and Rivas (2007) has done a survey on the level of poverty in the different areas in Bolivia between 1992 and 2001 and has compared the rural poverty levels to the urban poverty levels, which are relevant for the La Paz case. Poverty can be defined in two ways. The most used economic method of quantifying poverty is by measuring income and naming every income under a certain threshold (usually US$1 or US$2 per person per day). This however is an inaccurate method when it comes to urban poverty, because the cost of living in cities is higher, and because it does not account for temporal variations in income (O’Hare & Rivas, 2007). Therefore, another method is also used where non-monetary data is used to make an estimation of levels of poverty. This is called the unsatisfied basic human needs (UBN) approach and measures poverty in terms of peoples’ access to basic needs, typically housing, basic services, health and education. The results of the O’Hare and Rivas (2007) survey for the monetary method are presented in the following table: 1992 2001 Total population 1900 2350 Population in poverty 1182 1513 Urban population in poverty 605 765 Rural population in poverty 576 748 Population in extreme poverty 646 693

Urban population in extreme

poverty 189 198

Rural population in extreme poverty 457 494 Table 1 - Population in Poverty in the department of La Paz (x1000) It should be noted that these data concern the whole department of La Paz instead of just the city. Still, it is clear that in both the urban and rural communities, poverty has increased significantly. The second table shows the UBN approach. 1992 2001 Total % (absolute numbers)

Urban % Rural % Total %

(absolute numbers) Urban % Rural % Electricity 46 (765) 19 95 39 (891) 11 93 Water 71 (1180) 59 95 53 (1211) 36 73 Eduation 64 (1064) 25 86 49 (1119) 36 73 Health 65(1081) 54 84 64 (1462) 55 83 Total UBN 71 (1180) 59 97 65 (1508) 51 95 Survey population 1,663,123 2,285,907 Table 2 - Percentage distribution of unsatisfied basic needs including electricity/power, water/sanitation, education and health in 1992 and 2001.

18

This table shows that the percentage of people that have unsatisfied basic needs have declined. However, the absolute number of people living in poverty has still increased, and, perhaps more worryingly, the population density has increased with it. Therefore, this shows that the UBN method, where social data are included, gives more insight in the type of poverty that exists in the La Paz region.

Papathoma-Köhle et al. (2007) have set up a model that determines which factors influence the building vulnerability to landslides. In descending order of importance, these factors are related to the material of the building, the surroundings of the building, the description of the building’s side facing the slope, the existence of warning signs and the number of floors of the building. The self-built settlements in the more steep parts of the city are all influenced by these factors: they are made with weak materials on unstable surfaces, there are no warning sign mechanisms and building regulations have not been implemented (O’hare, 2005). Landslide vulnerability is however also present in the richer parts of the city. Though they are not located in the steeper areas of the city, but more in the central part with less steep gradients, they are more susceptible to the indirect effects of landslides, such as flash-flooding. Even upper class and elite groups living in the southern part of the city have not escaped damage. Economic losses per head of the population are higher in these rich parts of the city, and little compensation is paid by the government. To counteract these large losses, privately funded land use planning projects have decreased the economic damage of landslides. These projects include the building of terraces and drainage systems (O’hare, 2005). There is a clear link between poverty and infrastructural problems, because access to infrastructure is correlated to welfare standards, and the loss of infrastructure has clear direct and indirect consequences that affect the poor (Freeman, 2000). The low level of basic services provided is an important factor that influences the vulnerability in the poorest sector. 90% of the population in La Paz has electricity, but only 55% receives sanitation supply systems and water (O’hare, 2005). The drinking water is often taken from rivers with poor water quality and is then filtered. Landslides severely decrease the supply of safe drinking water. This has caused health issues and disease outbreaks. It has been shown that life expectancy is lower in the self-built settlements than in the formal city and child mortality rates are higher (O’hare, 2005).

A third way in which local economies are affected by landslide events is through losses in agriculture. Vulnerability to landslide events has caused larger food insecurity in Bolivia through the supply side (Cuesta et al. 2012). Through an econometric method, it has been shown that food insecurity has a positive relation with the level of public spending in the agricultural sector. Public spending on agricultural development is mostly driven by needs of vulnerability. The hazard of landslides further increases this correlation (Cuesta et al. 2012).

P

OVERTY REDUCTION

In the previous section the different elements at risk have been described. It is also elaborated how vulnerability is determined and influenced by poverty rates. At this point it is necessary to make some recommendations on poverty reduction. This has been done by the poverty reduction strategy paper issued by the Bolivian government in 2001. This paper has a number of recommendations to improve the productive capabilities of the poor and improve the living conditions of the population.

19

It concludes that increasing the level of social services will make an impact in reducing the percentage of the population not being able to fulfil basic needs. Furthermore, it has several recommendations to improve the habitability of the capital and to make changes in the rules of the housing sector. These include promoting the construction of drinkable water and sanitary sewer systems in peripheral urban and rural areas; constructing wastewater and solid waste treatment plants; providing technical assistance to small municipalities; and strengthening the sector institutionally. To improve infrastructure and institutional capacity in the housing sector, and to increase access to resources for financing housing, construction and improvement of low cost housing in rural communities are advised, as well as the reform of the regulatory and institutional framework of the sector and development of the secondary market for mortgage credit (PRSP, 2001). These recommendations by the Bolivian government are aimed at both of the aforementioned types of poverty in the self-built settlements: economic and UBN. Especially the improvement in infrastructure and water and sewer systems should decrease the amount of people who are not able to fulfil their basic needs. Another important way of tackling the landslide risk through poverty reduction is by looking at the housing system. Currently, for most of the people living in self-built settlements, making use of the official real estate market is above their financial means. The capitalist real estate market does not provide housing for the poorest sector, because they are profit based organisations that do not have the incentives to provide housing for those who cannot afford it. One way to decrease the number of people living in self-built settlements is by creating social housing systems that are financed by the government and have an incentive to meet the needs of the users instead of the subdividers. This also includes increasing tenure security, to protect the interests of the users (Farfan, 2003). The poverty reduction strategy paper even suggests that increasing spending on social housing may in term be beneficial, because it decreases government spending through poverty reduction. For instance increasing the health of the population is an important argument for increasing social housing systems (PRSP, 2001).

R

ISK ASSESSMENT

Through the different subjects that have been discussed, a combined assessment of the magnitude of the landslide risk in La Paz can be made. As stated before in the economic theoretical framework, the magnitude of a risk is composed of the hazard, the elements that are at risk and the vulnerability to these risks. The magnitude of the natural hazard is mostly determined by precipitation levels. Unfortunately, it is difficult to take measures that can ensure the stability of slopes, because of the variability of the rainfall events. The elements at risk are mostly due to the rapid urbanization the city has experienced. As described in the human geography section, poverty levels are highest in the periphery of the city, where landslide hazard is greater than in the city centre. This conclusion is further elaborated in the economy section, where it becomes apparent that the self-built settlements are of improper design and materials.

The vulnerability of the population is also greatly affected by poverty. Health issues have been caused by substandard infrastructure systems, and social inequality is enhanced by landslide events. This is further clarified by figure 4, which shows the risk to landslides of the different sections of the city. This map is a combination of a map showing the hazard and a map showing the vulnerability.

20

The hazard magnitude is calculated through 5 different sources, namely geological, geomorphological, geotechnical, level of inclination and flood hazard. The vulnerability is calculated through information about population, physical, institutional and economic aid and level of basic provision. It shows that there are 36 regions in the municipality of La Paz with a high risk of landslides.

Figure 5 - Map of landslide risk of La Paz. Source: Molina Rodriguez, 2011

Interestingly, this map was published in 2011 and was already being developed when the aforementioned Pampahasi landslide took place (Molina Rodriguez, 2011). Moreover, even the maps created in 2004 by the municipality of La Paz indicated that the affected areas where of high risk. Nevertheless, this knowledge did not decrease the magnitude of the disaster. This shows all the more that mitigation techniques are not limited to just the hazard mapping. This map further affirms that the most vulnerable parts of the city are where the self-built settlements are. Especially the south part of the city has a large area of high vulnerability. This is where social housing projects could decrease the potential results of landslides.

21 Figure 3 - Concept Map of the integration of different fields of study

C

ONCEPT

M

AP

22

O

PTIONAL

M

ITIGATION

M

EASURES

This section elaborates on possible measures that have the intention of alleviating landslides or preventing them from happening. The slopes can be stabilised through the use of metal bars that are drilled into the slope. This is the same principle as in the use of Ferro concrete, and significantly enlarges the soil restraining forces, provided that these bars are drilled into the bedrock that lies below the soil layer (Christopherson, 2015). Deforestation must be countered; planting of deep-rooting vegetation on the hill slopes will have a positive effect on the slope stability. Unfortunately, the rooting will take time and there is a possibility that a new landslide wipes away the freshly planted vegetation. To decrease this risk, a combination of terracing and reforestation might be an effective solution.

Hydrology management should be improved. The large quantities of water that weather, erode and undercut the slopes should be guided in such a way that there remains enough water for natural demands, but no surpluses with large eroding force.

In addition to the previous recommendation, draining of the slopes would decrease the total weight per volume in case of heavy rainfall events and saturated soils. This measure would decrease the shear stress and result in a decreased hazard. Noted has to be, that the drained water has to be transported away from the hazard zone. This could be a very costly operation, but it also creates chances. For instance power generation on a small scale.

23

C

ONCLUSIONS AND

R

ECOMMENDATIONS

This research has aimed to build an integrated framework for the city of La Paz, Bolivia. This framework, provided that it will be implemented by the cities’ municipal control, should result in a reduction of landslide hazards. Furthermore, the vulnerability, the elements at risk and the occurrence of landslide events, together with the reduction of loss of human lives, -health, housing, and infrastructure will be achieved.

T

HE

L

ANDSLIDE MITIGATION FRAMEWORK

The final framework contains multiple recommendations that can reduce the risk of landslides in La Paz, Bolivia. The recommendations are mostly derived from the different disciplines. All of these measures can be related to the formula of risk: = × × . In order to reduce the risk, the three factors after the equals-sign have to be decreased.

There has to be some sort of investment in technical measures that can increase the stability of the slopes surrounding La Paz. These measures have several effects. Furthermore, there are several other mitigation strategies that can have a positive effect on the society and the environment. The table below displays the possible measures that could be taken, and the elaboration on why this measure is functional.

Mitigation measure Functionality

Reinforcing slopes with metal bars Increase the soil restraining forces. Reduce the Hazard. Reforestation on the slopes,

together with terracing Increase the soil restraining forces. Reduce the Hazard. Draining of the slopes Reduce gravitational forces and increase the cohesion between soil molecules. Reduce the Hazard. Combat land use change Stop the further loss of trees, so the soil restraining forces do not decrease further. Reduce the Hazard.

Invest in an advertising campaign Reduce the population density in the area of self-built settlements. Reduce elements at risk.

Social Housing project Reduce the number of residents that live in self-built settlements. Reduce elements at risk. Poverty reduction project Decrease the poverty rates in the area. Reduce Vulnerability.

24

L

ITERATURE

Alimohammadlou, Y., Najafi, A., & Yalcin, A. (2013). Landslide process and impacts: a proposed classification method. Catena, 104, 219-232. Arias, O., & Robles, M. (No date). The Geography of Monetary Poverty in Bolivia. Brown, C. B., & Sheu, M. S. (1975). Effects of Deforestation of Slopes. Journal of the Soil Mechanics and Foundations Division, 101(2), 147-165. Christopherson, R. W. (2015). Elemental geosystems. Prentice Hall. Chong, D.; Druckman, J.N. (2007). "Framing theory". Annual Review of Political Science Colley, R. H. (1961) Defining Advertising Goals for Measured Advertising Results. NY, ANA. Cuesta, J., Edmeades, S., & Madrigal, L. (2013). Food security and public agricultural spending in Bolivia: Putting money where your mouth is?. Food Policy, 40, 1-13. Farfan, F. (2003) Formal and customary housing tenure initiatives in Bolivia. Habitat International 28, 221–230 Fairhurst, G. & Sarr, R. (1996) The art of Framing. San Francisco: Jossey-Bass. Freeman, P. K. (2000). Infrastructure, natural disasters, and poverty. Managing disaster risk in emerging economies, 55-61. Glade, T., Anderson, M. G., & Crozier, M. J. (Eds.). (2006). Landslide hazard and risk. John Wiley & Sons. Goffman, E. (1974) Frame Analysis: An Essay on the Organization of Experience. New York, NY et al.: Harper & Row Heins, C. (2011). Indigenous internal Migration in Bolivia, Causes and current challenges. KAS International Reports, (24-39). Huppert, H.E., and Sparks, R.S. (2006) Extreme natural hazards: population growth, globalization and environmental change. Philosophical Transactions of the Royal Society B 364, 1875-1888. Kahneman, D.; Tversky, A. (1984). "Choices, values, and frames". American Psychologist Kotler, P., & Keller, K. (2001). L.(2012). Marketing Management, 145-164. Leonard, O. E. (1948). La Paz, Bolivia: its population and growth. American Sociological Review, 13(4), 448-454. Mitchell, J. F., Lowe, J., Wood, R. A., & Vellinga, M. (2006). Extreme events due to human-induced climate change. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 364(1845), 2117-2133.

25 Molina Rodriguez, R. (2011). El Mapa de Riesgos 2011. Retrieved November 21, 2015, from http://rincondelosgeografos.blogspot.nl/2011/09/el-mapa-de-riesgos-2011-identifica-36.html Nathan, F. (2008). Risk perception, risk management and vulnerability to landslides in the hill slopes in the city of La Paz, Bolivia. A preliminary statement. Disasters, 32(3), 337-357. O'Hare, G., & Rivas, S. (2005). The landslide hazard and human vulnerability in La Paz City, Bolivia. The Geographical Journal, 171(3), 239-258. O’Hare, G., & Rivas, S. (2007). Changing poverty distribution in Bolivia: the role of rural–urban migration and urban services. GeoJournal, 68(4), 307-326. Papathoma-Köhle, M., Neuhäuser, B., Ratzinger, K., Wenzel, H., & Dominey-Howes, D.(2007). Elements at risk as a framework for assessing the vulnerability of communities to landslides. Natural Hazards and Earth System Science, 7(6), 765-779. PRSP. (2001). Poverty reduction strategy paper. Republic of Bolivia, La Paz, INE, 1991 Census. Roberts, N. J., Rabus, B., Hermanns, R. L., Guzmán, M. A., Clague, J. J., & Minaya, E. (2014). Recent Landslide Activity in La Paz, Bolivia. In Landslide Science for a Safer Geoenvironment (pp. 431-437). Springer International Publishing Scheufele, D. A. (1999) “Framing as a Theory of Media Effects.” Journal of Communication 49 (4): 103-22. Tversky, A., Kahneman, D. (1981). "The Framing of Decisions and the Psychology of Choice". Science 211(4481): 453–458. UNDRO, N. D. (1980). Vulnerability Analysis. In Report of Experts Group Meeting, Geneva.