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Flood management and slums formation in Magdalena?s River Basin-Colombia (página 2)

Enviado por Harold Hoyos Goez

Partes: 1, 2

Picture 1-1 La Gabarra Cesar Magdalena’s Flood

Every year many the communities and slums along the Colombian rivers flood plains are flooded. The solutions given to prevent, and mitigate these events are not the appropriate ones.

Picture 1-2 Flood in Magdalena’s river


Drain Area (1) (Km²)




Main rivers

Mean Precipitation (mm/year)

Mean Runoff (mm/year)


363 878


Magdalena, Cauca, Atrato, Sumapaz, Sogamoso, Saldaña, Bogotá,

300 to

2 500



76 500


Patía, San Juan, Mira, Bandó, Dagua, Anchicayá,

2 000 to

9 000



350 000


Meta, Guaviare, Arauca, Tomo Vichada

1 000 to

5 500



343 000


Amazonas, Vaupés, Guanía, Paraná, Caquetá Putumayo

2 550 to

3 500



8 370


Sardinata, Zulia, Catumbo

1 000 to

2 500





3 000


Table 1-1 Characteristics Main Colombian Watersheds

Source:FAO, 2000. ECLAC,2000

Colombia’s Potential Risk Flood Zones

Map 1-1

Source IDEAM 2002

Forced displacement of Colombian population due to the armed conflict. See Pictures 1-3 and 1-4

Picture 1-3 Displaced People moving to towns and flood plains and Guerrilla Fighters Picture 1-4

Map of Departments where most displaced people go and settle. See

Map 1-2

Source Codhes-Sisdes 2000

1.2 National Policies in Magdalena’s Flood Management

Colombia has been searching for more than 60 years a physical project where to join all the economic activities in order to protect the entire social infrastructure and the conservation of the nature.

Since the 50’s the management of the natural resources and the environment has been done by public entities, based primarily in the geographic area of the watershed.

These entities without fulfilling the main objective of managing the natural resources as public goods searching for the people’s benefit, they also assumed the role of taking care of the environment including activities such as planning, management, preservation, conservation and protection, failing in all of the activities mentioned above.

In the problems related to Magdalena’s floods the control measures where expressed only in structural measures and punctual solutions, overlooking an integral view of the basin.

The problems of flooding of Magdalena’s river at its tributaries has been intervened by the National government, executing actions through different institutions such as the Public ministry of construction, the Agriculture’s Ministry, Regional Corporations, Energy enterprises, all of them have been dealing with developed in isolated cases with no integral management and without the participation of the community and stakeholders.

However, in 1991 the national constitution was changed. With the new constitution the governors and the majors are elected by popular election. At the same time, the new constitution creates a new figure called decentralization, which means that each region, state or municipality are responsible for its own investment, and has to provide a good quality of life (health, education, infrastructures, among others), to all the population.

Thus the new constitution gives the autonomy to every department (state) to achieve their own goals and to solve their own problems. Hence, the role of the national institutions is to develop national guidelines in order to give some ideas or basic parameters to the regional and local institutions. The National guidelines can be flexible while the regional or local can be severe.

The General Direction for Attention and prevention of Disasters DGPAD. This office works together with other public, private and community organizations and with the National Institute Of Hydrology, Meteorology And Environmental Studies IDEAM. Both institutions are working together in warning the communities about the possible emergencies by radio stations messages or communications between government stations of alarms, due to the increase of water levels in rivers. Parallel to this in the private sector, there are NGO’s, the civil defense and the Red Cross. Civil volunteers that are attending the communities in case of emergencies.

In 1993 the national government created the Ministry of Environmentwhich implements the Regional Autonomies Corporations-C.A.R all over the country 35 in total including the Regional Autonomy of the Rio Grande de la Magdalena that are responsible for the conservation, protection, administration, recuperation and use of the natural renewable resources across the country.

1.3 The Armed conflict and the Slums situation in Colombia

The forced displacement is one of the biggest and serious manifestations of the armed conflict; it is a fight for the resources, the territory and political power.

The slum formation is product of forced displacement, this one considered as a national human tragedy, since 1985 has affected around 400 thousand homes that compose more than 2000.000 of Colombians.

During the two first years of Andres Pastrana’s government around 580.000 Colombians, were displaced by the armed troops including guerrillas and paramilitaries forces.

From a constitutional responsibility point of view the state is unable to avoid the displacement of people and the formation of slums, because the government does not have the capacity of establish sovereignty in the conflict.

The third part of the displaced people in 1999 escaped in a massive way through a same place, such as towns, cities, river flood plains and country borders, increasing the poverty, school abandoned and slums formation.

The government formulated some new policies for the attention of displaced population through a document of the COPNES (National Advisors for National Policies) edited a law in November 10 1999, emphasizing the its attention in supplying the basic necessities including a decent home for displaced people.


  • -Magdalena’s river basin faces slum formation and Flood management problems such as creation and implementation of the new policies, following with the institutions that are working in the area and according to the real problems that are affecting the river.
  • -Lack of integrated water resource management in all the national institutions, stakeholders’ participation and community workgroups formation.
  • -Drug conflict and empowerment of illegal armed troops, increases the power of fire, generating more violence and displacement of population.
  • -Necessity for the development of an integrated master plan for the local authorities has to be a priority.
  • -The study problem will be focused in most affected zone of Magdalena’s river basin, between Andina’s and Caribbean regions


This individual study will be focus on:

  • Studying the existing situation regarding to slum formation in the flood plains, flood hazard, and flood management practices in Magdalena’s River Basin.
  • Select the most representative area, which needs immediate intervention and flood management policies and practices.
  • Determine boundary conditions for immediate actions in a master plan that copes to slums formation and flood prevention.
  • Recommend institutional, improvements and measures for Magdalena’s river basin.


The methodology proposed for the individual study:

  • Data collection of the national situation about slum formation, floods and its prevention and mitigation actions.
  • Select some examples of slum formation and flood events.
  • Select a watershed and flood areas in which the study will be focused.
  • Analysis of the technical information and institutional information
  • Definition of boundary conditions and problems taken for the development of Magdalena’s river basin solution.
  • Conclusions
  • Recommendations

The time frame proposed for the project is:

Activity/ time

Week 1

Week 2

Week 3

Week 4

Week 5

Data collection


Select examples


Analysis of the information


Definition of Solutions


Conclusions and Recommendations



5.1 Magdalena’s River Basin

Magdalena’s river is the most important river in Colombia; it is located in the central part of the country, going through the Andinas region, which is the center of the country’s development.

It starts to flow in ¨¨el Paramo de las papas¨¨ mountain in the Colombian mountains chain in Magdalena’s lake, located in ¨Huila´s¨¨ department, it flows through the country from north to south with a length of 1536 km and an average discharge of 7100 m3/s.

The tributary area of the basin is 257.000 square kilometres, that Correspond to 22.8% of the total surface of the national territory. Its trajectory starts between an Andinas valley in the oriental and Central chain mountains the river goes through economic heart of the country, where the natural resources and the best conditions for development, because almost all industries, roads, dams and agriculture development are located in this region.

The yearly precipitation is estimated in a 2000 mm with a variation in the inner basin of 800 mm to 5000 mm in certain zones. The river in its first part presents a torrential flow, due to its steep slope, which starts decreasing, becoming in a meandering river, observing material of cobbles, gravel and sand this situation is seen as far as the town of ¨¨Honda¨¨where the river changes from meandering to braided, forming small islands, which is located in the Middle Magdalena. See table 5.1

Months of High and Low levels in Magdalena’s Basin Table 5-1

Sub Watershed

Months of High Levels

Months of Low Levels

Upstream Magdalena’s Basin 55.500 Km2

April, May, October and November

July, August and December

Middle Magdalena’s Basin 49.150 Km2

May, June and October

January and July

Downstream Magdalena’s Basin 24.705 Km2

June and October

January, February and July

Source Awad and Alvarez 2002

In the city of ¨¨El Banco¨¨ downstream the basin, the river suffers a new transition penetrating a zone with particular characteristics conformed of numerous natural canals and lagoons, forming a network of canals through all the system. This area suffers of periodic floods during the months of October and November, affecting approximately 2 million hectares in the most severe events and 730.000 hectares in the less severe events. See table 5.2

and the dynamic of the river.

Duration of Flood and Flooded Area Table 5-2

Flood Type

Duration of Flood

Area in Ha x 10



Less than 1 month.




1 to 3 months




3 to 6 months




6 to 12 months











Source Awad and Alvarez 2002

5.1.1 Facing the Flood Problems

Magdalena’s river basin has a variety of hydrologic conditions, and all kinds of tributaries, this is due that is located in a unique geographical condition, among three chain mountains, the hydrological network of the basin is abundant, where all its tributaries converge, producing situations of floods in its floodplains and vicinities.

In the basin two types of floods can be established according to the regime of the flow, floods in torrential type and floods in alluvial type. The torrential are originated in the mountain area of the Andinas zone, corresponding to Magdalena’s basin, where it is formed of with high slopes during winter season that transform all tributaries in dangerous rivers, originating floods in its floodplains.

Another phenomena that is related to floods are generated by avalanches, that occur because of ice melting, or water storage due to the obstruction of the flow, this occurs because of landslides and generate high volumes of water, that flow with an extremely force downstream, producing erosion in the embankments flowing with big stones, high amounts of sediment which destruct anything in its vicinities.

These are the worst phenomena in Magdalena’s river basin, and are the ones that generate material and human losses. The rains in Magdalena’s river basin consist in a bimodal way with maximum events in April and May October and November, the highest discharges can be detected in the second period of the year, where the capacity of storage reduces considerably.

Downstream storage water capacity of the basin is estimated in 40.000 millions of Square meters, in Colombia as consequence of floods and other natural events, the material losses can reach 35 million dollars, more than 65000 thousand people affected by the floods, and 250 human life losses. See table 5-3

Magdalena’s Flood Losses in Million Dollars. Table 5-3


US$ x 103





























Source Awad and Alvarez 2002

Magdalena’s river basin is one of the dangerous of the country, taking into account the 90% of the losses and 70% of human losses, and also agriculture, industry are affected indirectly, in 1994, the floods generated losses to 8000 houses and more than 250.000 people were homeless, corresponding to the 47.5% and 80.7% to the total of events of catastrophic classification, showing that floods are the most important event that affect the economy of the country. See Figure 5-1 and Figure 5-2

Figure 5-1

Source Codhes-Sisdes

Figure 5-2

5.1.2 Mitigation Measures in Magdalena’s River Basin

The experience shows that in the basin some projects were located to control floods, which represent a low percentage, according to the dimension of the problem. The projects were made in order to solve or mitigate some specific zones, but not a master plan or design for the whole basin.

5.1.3 Hydrometeorologic Alert Network in Magdalena’s River Basin

Since 1970 were given the first steps for the establishment in Colombia of a Hydrometeorologic network, under an assessment of a Canadian enterprise, which after analysing the situations of water levels and main parameters of the river in that time recommended to create an alarm radio network based mainly in the installation of a series of radios in high frequency to prevent and start the alarms in case of water level increase, the application of new methods of analysis and the access of improved technologies had increased the accuracy and the opportunity of the systems of alert to obtain constant data in real time of hydrologic, atmospheric and periodic images.

In Magdalena’s river basin 59 automatic stations have been installed for satellite transmission of data but the operation, maintenance and transmission of information still needs to be improved. See Table 5-4

Monitoring Stations and Entities in Charge of Monitoring See Table 5-4

Entities in charged of Monitoring

Number of Stations











Source Awad and Alvarez 2002

The specific functions of the program are:

  • Keep on monitoring during the 24 hours the parameters and indicators of risk that point through and analysis of warning system
  • Keep the statistical data in all the hydrologic parameters, and all radio, satellite information available for an immediate use.
  • Generate daily evaluations of the information.
  • Obtain, tabulate, and make graphical reports in real time and its analysis.
  • Prepare and analyse hydrological models, report and send the corresponding reports to the main stations.
  • Verify and calibrate the models used in Magdalena’s river.

5.1.4 Non-Structural measures for prevention.

In the last decade maps of risk areas of flood have been developed in 1:2000 scale with Return periods of 2, 20, and 100 years, these maps are used to make the soil uses maps, in order to detect the risky zones and prepare the plans for future region development.

The Measures for protection and commonly used in the past years are the structural ones like dikes, groynes but the appropriate use and management of the areas with risk of flood should be implemented in a complemented way.

5.1.5 Navigation Uses of Magdalena’s River

The navigation canal has a length of 22 kilometres from its outlet as far as the bridge ¨¨Laureano Gomez¨¨, the government edicted the first law in 1993 with the responsibility of keeping the navigation depth of 30 feet for the navigation canal. The maintenance of the river depends on its discharge, requiring bathymetry measures every week in order to determine dredging zones.

The reactivation of the river transport will lead to the development of the Caribbean region, connecting the country with the rest of the world with the port of Barranquilla in the coast and Puerto Berrio’s port in the inner Country.


6.1 Causes of Slum Formation in Colombia

The armed conflict does not stop, it tends to affect more regions and more social sectors in the country and also to degrade more and more, because none of the armed actors exclude the population, in the other hand they try to deep them in their fight.

The forced displacement is the biggest humanitarian problem that Colombia faces; besides of the 2000.000 million displaced people including all kinds of political, social and cultural ties, because all the big problems this generates for the future of Colombia, and the tendency to the social separation. The persistence of these migratory phenomena is really challenging the society, because by the force is being changed the social and demographic structure of the expulsion zones, increasing spontaneously and chaotic the population in zones that are not prepared for this sudden invasion, increasing the social problems environment degradation and poverty.

More than 3000.000 Ha of land have been abandoned by 90.000 families with rural ties between 1996 and 1999, challenging these small families for survival in conditions out of their own environment. See Figure 6-1

Figure 6-1

Source Codhes-Sisdes

The humanitarian situation in Colombia remains critical civil war, forced displacement, assassinations and kidnappings of civilians, and escalating urban violence coupled with wide spread poverty, have worn though the country’s social fabric, moreover the armed conflict has intensified since peace talks between the government and the Revolutionary Armed Forces FARC broke down in February 2002, two million people displaced by conflict since 1985 are one measure of the human toll. These are often society’s most vulnerable subsistence farmers, women children and ethnic minorities and their health is seriously affected. There are high morbidity and mortality rates from communicable diseases, as well as high levels of malnutrition

6.2 The Internal War and Slum Formation in Magdalena’s Flood Plains

The slum formation and forced displacement in Colombia is a phenomena that gets more difficult for all the rural population where people are facing problems of war. From the perspective of human rights, the existence of this moving populations, with varied ages and gender, questioning the responsibility of the country and its legitimacy, requiring an imperious obligation to repair the rights, and prevent migrations and protect the victims from the armed conflict. The forced displacement destroys the environments, separates families, societies, and impacts in a negative way the quality of life affecting the life of everyone, 75% of the displaced people come from rural zones, indigenous and afro Colombian communities.

The responsible of the forced displacement are Guerrillas with 43%, Paramilitaries 35% and armed forces 9% unknown 9% and others 4%. The slum formation in Magdalena’s flood plains starts with a struggle for a physical settlement, basically to supply its basic needs, such as energy water supply, and sanitation. They settle in the river flood plains because there they can obtain minimal basic needs like wood for energy, fish, water, sanitation, and some of them fertile soils for growing small amount of crops. See Figure 6-2 and Figure 6-3

Figure 6-2

Source Codhes-Sisdes

Figure 6-3

Source Codhes-Sisdes

In the zones where displaced people arrive, they are affected by stigmatisation and racial discrimination, the circumstances in which the process of adaptation develops into the new scenarios, where new out comers tend to lose their identities, occupying small spaces denying its roots in order to survive in their new habitat.

In the invaded flood plains there is a high percentage of communities which try to solve their dramatic situation of high-level mal-nutrition in children and diverse illness due to climatic conditions of the new zone. In the slum formation ¨¨Nelson Mandela¨¨ located in the Department of Bolivar in Magdalena’s river flood plain, it was found that the dwellers were living in extreme conditions of no sanitation. The permanent disposal from houses and trash in decomposition, circulating all around the houses, in one of the sectors of this slum 1027 children were found in bad conditions of nutrition, there were no sanitation conditions, no health care and no study possibilities. See Figure 6-4

Figure 6-4

Source Codhes-Sisdes

The civilians strategy for war is to emigrate to places to avoid war and find safe places for their families, while paramilitaries, government and guerrillas fight for territories and lands of high economical value. The displacement without truce show a population of 288.127 persons that belong to 57.625 families that were obliged to escape in 1999 by direct or indirect action of paramilitary and guerrilla’s groups but the history of displaced people starts increasing in between 1985 to 1994 with 89.000 displaced families, in 1995 181.000 families, in 1996 257.000 thousand people, in 1997 308.000 people displaced that is to say in Colombia there are around 2000.000 million people displaced from their living and working places as a consequence of the armed conflict in the last 15 years. The displaced people are the reflex of changing scenarios in the geography of war, a manifestation of hate for the civilians that struggle in every place they find without rules and weapons for their survival and their families.

6.3 The Changing Geography of Magdalena’s Floodplains and Formation of Slums

The changing situation and increase of war affected the departments of Bolivar, Norte de Santander, Antioquia and Cordoba all situated in Magdalena’s river basin. This situation was reached by an increment of the conflict in this territories mainly in the central and northern part of the Andina’s region, due to their economical development, natural resources, fertility of soils and the lack of presence of the state, without any guarantee of security for the population.

This phenomenon generated that the displaced population escaped to places of important localization of commercial and agricultural activities through zones for new colonization or reach soils, in order to find food security, protection or away from the armed conflict. Approximately 200.000 thousand people invaded the river flood plains of Magdalena’s river in the past years, families coming of every part of the downstream departments that are having war conflict in their areas, however the situation is still in dramatic conditions because of lack of solutions of the government in order to incorporate them in projects of integral participation. See Maps 6-1 and Map 6-2

Departments in the Conflict area Where Displaced People Emigrate. Map 6-1

Source reliefweb 2004

Often Flood Areas in Magdalena’s River Basin. Map 6-2

Source IDEAM 2004


7.1 Introduction

Floods and slum formation are one of the main problems in the Magdalena’s river basin. War conflict is displacing thousands of people from their own lands to river floodplains and increasing danger of flooding population. Thus, the critical flood areas in Magdalena’s River are located on the lower Magdalena mainly in the Departments of Bolivar, Cesar, Magdalena, Cordoba, Antioquia, Cesar, Santander and Atlantico

In 1991 the national constitution ordered to create a management structure the Rio Grande de La Magdalena Corporation in order to guide and formulate an Action Plan for the Water Resources Management in Magdalena’s River Basin.

All along the river Corporations were created in order to manage, plan and distribute the river. See table 7-1

Departments and Local Corporations in Charge of Managing the River.

Table 7-1










Corp. Sur de Bolivar





Cartagena de Indias



Corp.Autonoma del Atlantico

All of them are in charge of managing the natural resources along middle and downstream part of the river and also they are in charge of:

  • Improving navigation along the river and the environment.
  • Improving the river banks protection works
  • Development of a framework for the use of the flood prone areas in order to reduce and to prevent the damages and losses due to floods.
  • Hydropower exploitation resources taking into account the navigation along the river.
  • Protection of the biological resource existing along the river.
  • Touristic recreation along the river.
  • Coordination and supervision of the environmental projects, lands and soil uses distribution.

None of them was created to attend the problem of slums formation in the floodplains, and that is the reason these institutions, do not have the mechanism and the experience to face these kind of problems, besides of this each institution works separately and its measures and studies are used in an independent way without any cooperation or link from the other corporations for the same river.

7.2 Water Resources Management in Magdalena’s Downstream River Basin

7.2.1 General features

The characteristic of a flat area in downstream watershed makes it one of the largest floodplains than in other regions of the country, it has a capacity of 40,000 km2 for flood absorption, this area is not enough for sufficient storage for flood events making of it a vulnerable area for flooding in every rainy season of the year, besides the formation of slums is increasing day by day in this region due to the displaced people generated by war conflict

7.2.2 Policies, Trends and Guiding Principles

Policies and trends are now present in the country for managing Magdalena’s river basin problems; the existing information will be used to define the main component of the framework.


7.3.1 National Policies

The Ministry of Environment, Agriculture and Transport define flood policies in the country, as a complement other corporations and institutions are related with floods management like Corantioquia, Cornare, Corpocesar, Cardique, Cormag, IDEAM, the local authorities and CorMagdalena.

However, there are other institutions that are associated with floods and are linked with the Agriculture and Rural Development Ministry those are, the Colombian Rural Development Institute INCODER, The National Agency for Land Use FONAT, and the Superior Council for Land Use, their role in the flood management field is explained as follows:

  • Agriculture and Rural Development Ministry

In the field of flood management this ministry has the responsibility to assign the areas that frequently have problems of floods. Those areas have to be assigned as land use districts; this category allows the local authority to ask for the execution of the required structures and the funds necessary to improve flood defense in the area.

Linked to this ministry there are other institutions like the INCODER, FONAT and the Superior Council of Land Use.

The Superior Council of land use is the institution in charge of the coordination of all national policies, also is the supervisor of the actions that are executed by the other institutions in the area of flood management.

IDEAM is the national institution responsible for the hydrological and meteorological information, however its role in this ministry is to define the parameters that have to be taken into account in the realization of the hydraulic studies in the area of concern, hence the land use districts.

The INCODER is the institute in charge of the execution of the structures, which were designed by the consultant or by the IDEAM.

The FONAT is the office in commanded to supervise the financial aspect and the management of the project executed by INCODER. The organization of the Ministry

Therefore, the ministry and the linked institutions are responsible for the execution of the structures necessary to prevent and mitigate floods in the land use districts.

In the other hand the ministries in charge of attending social problems like forced displacement, are Ministry of social protection, ministry of education, Environment, and human rights, all of them work in a separate way but the focus in the same objective that is to try to guarantee the people’s rights and normal conditions and facilities to live, in theory.

However, these institutions are working more in the last years existing problems of the country than in avoiding the formation of new slums in the floodplains for that reason it is necessary to encourage local authorities in order to attend the local necessities and work with the tools that already exist in order to prevent flood losses in the future.

The local authorities are responsible for the future use of the floodplain areas. These areas will become land use districts according to the law 41/93, and also will be a property of the state, once it is declared a land use district.

The use of these areas can be defined in the beginning by the local authority but it is recommendable to ask the Ministry of Agriculture what kind of project can be developed.

Therefore, the local authorities have to involve the communities around the project that will be executed in the floodplain area in order to improve the quality of life of the inhabitants in the area.

7.3.2 Local policies for Flooding

There are no local policies for slum formation, for flood mitigation or flood prevention. The General Direction for Prevention and attention of Disasters and their departments in the main cities an some towns execute programs that are developed to warn the communities or to help them in a precarious way when the event occurs, but nevertheless in the small towns or invaded floodplains there are no policies regarding this field. Trends

Trends about mitigation and prevention of natural hazards in Colombia are relatively new, starting in 1989, when the national government created the national office for prevention and attention of natural disasters, as a consequence of the Armero’s flash flood in November of 1985.

In the same decade the central government established some policies that took in consideration floods as a natural hazard. These policies were not enough and were not well applied in this area due to the lack of experts knowledge, and tools.

Although, the international concern about this matter is focus in the reduction of the flood risk. However, in Colombia this trend is far away from this task, the national and local effort is focused in solving local issues more than reducing the flood risk in the floodplains.

Flood prevention, flood mitigation and slum formation are new topics in which the national policies should trend but sometimes due to political reasons and lack of vision of the main governors and parties involved. There is a general amnesia in the government and in population for the past flood events, and people start building again in places that were affected by flooding years ago.

7.4 Guiding Principles

7.4.1The Local Authorities Role

The local authorities have to define; the priorities of the region what are the floods problems that are going face every year (flood risk assessment). Besides they have to make the territorial organization plan which consist of an inventory of the existing buildings and in the future land use projects, the populations settled in it, and the existing infrastructure.

Local authorities have to establish an educational program around the area in order to inform the people about the project and the necessity of their active participation.

The central government requires that the local or regional authorities contribute financially with a percentage of the funds, as a result it is important to establish in the beginning of the year an item to facilitate the payments.

The local and regional authorities have to separate every year an item in their accounts for the maintenance of the structures. The community can do the maintenance, however the local or regional authorities are responsible. Therefore, the authority has to establish a monthly maintenance book, which allows the person in charge to do the future works and also serves to follow the behaviour of the structure. Guiding Principles for the Phase of Studies

The main role of the Hydrology, Meteorology and Environmental Institute IDEAM is to encourage the communities to define the areas that are in risk of flood, and then it has to identify what are the most important parameters that have to be taken in consideration In order to classify a land use district in the area of interest.

As the land use district has to be defined by the local authorities together with the IDEAM, is important to define the following aspects:

  • Topographical data

The topographical data has to be made IDEAM, the Cor-Magdalena or the local entity responsible for flood management. This data has to be actualised each five-year in order to have a record of the changes in the river morphology.

  • Hydrological data

In order to define if the area has a flood risk it is necessary to analyse the available hydrological data. The institution in charge for this information and its analysis is the IDEAM; it has to provide the existing data and the record of information for at least 50 years.

In the same way the IDEAM has to analyse and provide the critical flood level, water levels, the daily and monthly water levels registered in the area that allows a complete analysis of the information. In all the cases the IDEAM is responsible for the hydrological data and for the collection of data.

  • Lack in information

For the definition of the land use district it is important to take into consideration those cases in which there is a lack in the hydrological information. In that case it is necessary to analyse the data upstream and downstream of the area. In those cases the analysis has to be done with the nearest stations, interpolation has to be made and the precipitation amount has to be defined in the area using the available methods. The analysis also has to consider the backwater due to floods.

  • Flood Map

In the case of an existing map of the vulnerable flood areas it has to be actualised each-five years taking into account not only the changes in the regimes due to climates variability that can modify the level in the reach but also the bank erosion that can be present in the bend of the river. In the case of bank erosion the area of the land use district can be change.

If the area or land use district is not within the existing map, the IDEAM has to analyse the hydrological information and the water level in the reach. Thus, the IDEAM has to define the possible areas of risk, in this analysis the entity has to take into account the actual topography area and the bathymetry of the river.

  • Flood Hazard Map

In those areas where there is a city or small town it is important to define the flood hazard map, in order to define the flood risk for the population with the purpose to update the warning program correctly in case of flood.

This tool has to be implemented by the IDEAM and the resulting information has to be communicated to the local authorities. The accuracy of the information has to be a task for IDEAM.

  • Flood Defence Structures

The designs of Flood defence structures have to be made by the contractor or IDEAM. However, the main parameters have to be given by IDEAM and the local corporations. The design has to take into account the following procedure and aspects in order to have an integrated solution for the area and the communities located downstream and upstream of the project.

  • Existing structures in the area

The local authorities and the regional corporation have to draw up an inventory of all the existing structures located at least 5 km upstream and downstream of the reach of concern.

In the inventory, it is necessary to describe the actual state of the structure, the type of the structures, the dimensions, the materials and the behavior of the river in the area among others.

  • Geographical and geological information

The area also has to be defined by means of the morphology records that exist in the Agustin Codazi Geographic Institute IGAC. This information is available in aero photographical pictures of Magdalena’s River.

Geological data can be gather in the IGAC or made again by the contractor in case of some mistakes in the existing ones. With this information the contractor can define how the river and its banks are behaving or predict its behaviour by the use of hydrologic and hydraulic models. At the same time it is possible to determine the characteristics of the new structure, like dimensions, materials, foundation and location.

  • Possible retention areas upstream:

Flood defence design has to take into account possible retention areas. This assessment can influence the flood risk downstream of the concerned area and can provide a reduction in the cost of other structures.

  • Existence of a tributary.

In the case of a tributary it is important to take into account the hydrographs in the tributary and in the studied river reach. This analysis can conclude the necessity to carry out a project in the tributary instead of the main river.

  • Modelling of the proposed structures

All the proposed structures have to be modelled in order to observe the behaviour of the river due to the construction of the structure.

The inputs of the model have to take into consideration the critical situations of the river, which means the actual situation (without project) and the situation with the construction of the structure proposed.

  • Environmental Impact Assessment

Every future structure that will be constructed in the reach has an impact in the river and on the environment. Therefore, it is necessary to carry out an Environmental Impact Assessment EIA in the area.

In fact, with the EIA the negative and positive impacts can be defined, and the local and regional authorities can act to reduce the impact or in the contrary they can make good use of it. Guiding Principles for the phase of Construction

The INCODER it is responsible for the construction of the proposed structures; as a result is important to take into account the recommendations given by the Environmental Impact Assessment. On the other hand, the local and regional authorities have to supervise the construction activities in order to avoid any kind of impact that was not evaluated in the EIA.

The contractor and the local authorities have to analyse the source of the material required for the construction.

7.5 Flood Management

7.5.1 Non-Structural Public Education

One of the most important tasks of the local authorities is the public education. To accomplish this goal the local authorities have to work with the DGAPD and the civil defense in order to increase awareness of the people about the importance to follow the programs and warnings given by the institutions. In other to achieve this goal the civil defense and the local authorities have to carry out an alarm program in the local schools and a simulation programs in order to prepare the inhabitants for flood events. Also, it is necessary to print out some manuals with the basic information in which the people can understand in an easy way what they have to do in case of flood. Flood Organization

In order to implement the new approach to water management, the various local authorities will have to take up their responsibilities. Administrative agreements between the national government, provincial authorities, water boards and municipal authorities will be required for rapid implementation.

Administrators must know who assumes responsibility for what in order to ensure timely implementation.

The institutions are working independently, thus it is necessary to coordinate all the branches around one institution. In the case of flood risk this institution has to be the General Direction for Attention and Prevention of Disasters that is the national coordinator for the mitigation and prevention of flood events. In this new scheme the DGAPD has to be the leader in this area.

The following procedures have to be take into account in all the emergency programs that will be carried out by the local and regional entities

  • Public official alerting. IDEAM and DGAPD

Local authority Civil Defense

Red Cross

  • Flood emergency response plan activation

Local authority Civil Defense

  • Staffing the emergency response operation Center

Local authority Civil Defense

  • Emergency broadcast and warning system activation

Local authority Civil Defense

  • Emergency instructions to the public

Civil Defense

  • Emergency medical assistance activation

Red Cross

  • Reception and care system activation

Local authority Civil Defense

  • Shelter and evacuation plan activation

Local authority Civil Defense

  • Search and rescue activation

Local authority Civil Defense

  • Resource mobilization activation

Civil Defense

Red Cross Floodplain Regulations

In those cases in which the floodplain can be used for other purposes according with the IDEAM recommendations, the local authorities have to implement the regulations for the district. In the same way, the people in charged of the land have to take into account the maintenance of the flood defense structures.

In the areas in which there is a city or small town the regulations have to take into account the actual use and the risk area defined within the flood hazard map. The local authorities have to do a flood risk assessment, in order to know the maintenance costs of the inhabitants in the area versus the annual cost that is necessary to attend the emergency.

Eventually, the residence, the educational and industrial sectors have to be moved to other areas or reduce the inhabitants per square meter in order to reduce the risk of life losses. As this is a challenge for the local authorities the mobilization program has to be implemented for a long term. Property Acquisition and Floodplain Mitigation

According to the policies, the land that is required for the districts can be negotiated with the actual owner or in the extreme case when the owner does not want to sell the land to the local authority. This entity can take the land and declare it as a general benefit area, which means no payment for the land, because the general benefit is over the particular benefit.

This is a useful tool, in the sense that the land that will be necessary for the implementation of flood defense structures should be a government property. This allows the state to reduce the local losses and the amount of the affected people in the area due to floods.

7.5.2 Structural Measures

The structural measures that can be done in the area have to be defined according to the local river conditions.

Some of the most common structures used in order to prevent floods. See Table 7-2

Types of Structures for Flood Protection in Magdalena’s River. Table 7-2

Type of Structure



Land protection.

Sheet pile

Longitudinal protection


Flexible / gabions

Side slope and moderate erosion.

Hard / concrete bags



Bank protection /reduce the river velocity in the sides of the river, increase sedimentation

Non-permeable groynes

Change the river flow, bank protection.

The design of the flood defence structures has to take into account the following river aspects:

  • Morphological changes over the river
  • River bed scour due to the structure
  • Possible effects due to the structure in the river
  • Infrastructure structures (bridges, road etc.) upstream and downstream of the structure proposed.
  • Inundation Water level in the reach
  • Source of Materials in the area

7.6 Policies and Measures for Slum Formation

In 1997 the national government created the National System for and Integral Attention to Displaced People (SNAIPD) by the law 387 of 1997, besides of designing a new economic and political plan for managing the internal displacement due by the armed conflict.

It is composed by 14 government ministries and other public, private and community organizations covering various areas such as agriculture, social security, health and education. The Social Solidarity Network (RSS) created in 1999 manages the SNAIPD, coordinates and oversees assistance to displaced people, and those at risk of displacement, plans and delivers services to officially registrated internal displaced people.

Despite this extensive legal and institutional framework prevention of displacement is the weakest component of the government response, it has taken inadequate measures to prevent displacement and formation of slums in the river floodplains.

7.6.1 Colombian NGOs

Displaced Colombians have organised themselves and worked to assert their demands. In 2000 the internal displaced people formed a national coordinating body to advocate for better government assistance. Attacks on civil leaders society remain a major obstacle to work of national NGOs, and hundreds of leaders of displaced communities have been assassinated

Despite security risks local human right and humanitarian agencies have been increasingly active in providing the displaced people with legal advice, physiological support, food and medical assistance.

Many NGOs in Colombia work to promote long term solutions for internal displacement strengthening leadership, capacity building, and integrating the displace people in host communities.

The impact of NGOs however is limited by lack of funds, attacks, lack of state support, and insufficient coordination.

Despite an increasing number of assassinations of its members, the Church, through the pastoral social, and the Colombian Red Cross has played a key role in assisting the displaced people. It provides them with registration, food, medical aid and advocates for their rights.

The new laws and policies related to slum formation in floodplains practically do not exist because it is an emerging problem but some indicators will be given in the way to tackle this problem.

7.6.2 International Response

The international response has not been adequate for the scale of the crisis. The UN has sought to promote an interagency coordinated response to internal displaced people with a first humanitarian plan of action launched in November 2002. This budget with a budget of $ 79.4 million dollars, however fell short of raising the expected support.

A second plan was developed jointly by the UN members of civil society and government of Colombia, amounting to around $185 million for 2005

In spite of its dramatic scope, Colombian displacement crisis remains largely forgotten and the international community will need to show political will and more generous financial backing to support the work of humanitarian and human rights organizations working in the country.

7.6.3 Trends

It is important that the government and nongovernmental organizations assume the slums as a people with all rights

The government in collaboration with NGO’s and stakeholders must strengthen and encourage actions with the country, in order to develop the minimum basic sanitation services for the slums, in Magdalena’s river basin, prepare some areas for displaced emergencies in those towns where the armed conflict is strong, in order to maintain people in good conditions in safe places while combats are finished or while the government takes control of the zones of war.

The national system for an integral attention to the displaced people focuses in directing the changes of the new slum formation in cities, towns, river floodplains and any free space where humans can settle away from war conflict.

When a force displacement occurs, immediately the major or governor of the town sends an emergency message to the main office to the capital city of Bogota, they just give the order to designate the amount of resources necessary for solving the emergency, while the displaced people are located temporary in the stadiums, schools or fields of the town. In these conditions the ministry of social security designates or makes a plan for future relocation or sending them back to their own lands.

The situation goes out of their hands, when the conflict in the area still persists and the resources diminish day by day and the government stops supporting them, that is when they start settling in the vicinities of the cities, towns and river floodplains trying by themselves to guarantee their lives and conditions they used to have before.


8.1 Conclusions

Flood effects over the population increases every year with new dwellers coming from the rural part to the floodplain areas than in the developed as a consequence of the displaced people due to the violence and the poverty in Colombia that cannot have other place to live and also because of the lack of regulations and proper government plans for developing these areas.

Slum formation increases every day in Magdalena’s river flood plains as the power of conflict increases day by day, measures, emergency plans local and international cooperation is needed in order to tackle in an appropriate way and give good solutions to the problems of slums.

In Colombia the flood areas are located in the downstream Magdalena’s basin, however the highest percentage of affected people is sited in the Magdalena’s basin, where 70% of the country inhabitants are settled along the watershed especially downstream where the economic region is more developed.

The government tries return policies and measures for people living in the slums and Magdalena’s floodplains, without knowing the dynamic of the war, and the lack of real guarantees for the slum dwellers. In the same way, the government tries by solving the problem by a negotiated solution, but while this is possible, they do not have responsibility with the slums in river floodplains that are daily struggling for survival.

The actual focus of the government facing the formation of slums in the floodplains in Magdalena’s river has been limited by the lack of money, ineffectual in preventing, precarious in protection and attention of the affected communities, and very late for executing actions to tackle the problem.

8.2 Recommendations

In order to improve target 11 for the Millennium Development Goals by the year 2020 several considerations must be taken into account in Magdalena’s river basin

The new approach to water management policy requires an effort at all administrative levels. A clear division of roles is required to ensure effective co-operation. Bringing spatial planning policy and water management policy closer together reinforces the need for this. Administrators must know who assumes responsibility for what in order to ensure timely implementation.

Formulation of regional outlooks on water management and implementation programmes combining the approach to safety and water related problems with the approach to floods in Magdalena’s river basin and slum formation in its floodplains.

Designate and implement water retention areas and emergency flooding areas for rainy seasons in Magdalena’s downstream river basin.

Strengthen links between social ministries and flood ministries in order to generate a plan together for flood risk alarm prevention, slum attention and emergency plan of contingency In case that flooding.

Searching for the achievement of target 11 national government and local authorities should prepare shock absorbing zones consisting of certain amount of area with proper facilities and basic sanitation and a reasonable area for cultivating, in those places where armed conflict is intensive, so that the new settlers have almost the same conditions of their coming places for a certain period of time.

In order to establish a master plan for flood management and slum protection, in Magdalena’s river basin several measures must be taking into account, such as linking the institutions involved in flood management area like IDEAM, IGAC to NGOs, the social ministry, the environment ministry and Social Solidarity Network to establish emergency plans and alert networks in case a flood occurrence or displaced movements; besides of establishing the function and relation among those institutions and what are the responsibilities of each one.

Encourage awareness of flood risk in the slums by local leaders, radio stations, churches messages, school advertising and community training programs for evacuation.

In order to solve many uncertainties about the dynamic of the river hydrologic analysis, hydraulic study should be made over the dynamic behavior of the river using and calibrating mathematical models that allow to know the evolution and modeling protection facilities and protection against floods.

Maintain, actualise and manage every 4 years of government the information related to changes in the river water levels, bathymetry, characteristics of the river and floodplains as well as the amount and condition of people living in the slums.


Final Report of the Inter-American Seminar-Workshop Reduction of Vulnerability to Floods in River Basins. Foz do Iguacu. Brasil November 29 1995

Colombian Floods. Situation Report No 1. November 2004

N. Douben, Flood Management Lectures notes, Unesco –IHE, 2005

Cor-Magdalena, 2002, Partial Action Plan for the Magdalena River Basin, Bogotá, Colombia.

This war is not ours and we are losing it. Codhes –Sisdes November 2000

Combats and Displaced people in Colombia. MC NGO October 1999.


Harold Hoyos Goez



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