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Akademische Arbeit, 2012
71 Seiten, Note: 4/4
1.3 Statement of the Problem
1.4 Research Objectievs
1.4.1 General Objective
1.4.2 Specific Objectievs of the Study
1.5. Research Questions
1.6 Significance of the study
1.7 Scope of the study
1.8 Description of the study area
1.8.2 Demographic Data
2.2 Definitions and Concepts of Flooding
2.3 Causes of Flooding in Urban Areas
2.3.3 Climate Change
2.4 Vulnerability of People to Floods
2.4.1 A Vulnerability Framework
2.5 Flooding and its Impact
2.5.1 Economic Impact of Flooding
2.5.2 Social Impacts
2.5.3 Environmental Impact
2.6 Coping Strategies
2.7 Aspects of Flood in Urban Context
2.8 Flood Management
2.8.1Management of Urban Drainage
2.9 Flood Vulnerability, Impact and Coping Strategies in interantional perspectieve
2.9.1. Flooding Impact and Coping Strategy in Scotland
2.9.2 Flooding Impact and Coping Strategy in Korail, Dhaka
2.9.3. Flood Impact and Proactive measurs in Mumbai, India
2.10 Flood Disaster Profile of Ethiopia
2.10.1 Policies and Institutional Frameworks Related to Disaster In Ethiopia
3.2 Research approach
3.3 Research Methods
3.3.1 Research techniques and instrumentations
3.4 Sampling design
3.4.2 Sampling Frame
3.4.3 Sampling Unit
3.4.4 Sampling techniques
3.4.5 Sample Size
3.5 Source of Data
3.6 Data Analysis and Interpretations
3.7 Data presentation
3.8 Limitations of the study
4.2 Socio-economic Data of Respondents
4.3.3 Result and Finding
4.3.1 Vulnerability of People to Seasonal Flooding in Sawla Town
4.3.2 Causes of Seasonal Flooding in Sawla Town
4.3.3 Impacts of Seasonal Flooding in Sawla Town
4.3.4 Coping Strategies and Adaptations to Flooding in Sawla Town
4.4 Interpretation and Discussion
4.4.1 Vulnerability of People to Seasonal Flooding in Sawla Town
4.4.2 Causes of Seasonal Flooding in Sawla Town
4.4.3 Impacts of Seasonal Flooding in Sawla Town
4.4.4 Coping strategies to adapt seasonal flooding in Sawla town
Sawla town is geographically inscribed by the chains of mountain range from south to west, and from west to north. And the main town is dissected by two crossing rivers namely, ‘Womba and Cholea’. Due to increasing demographic dynamics of the town accompanied by rapid urbanization, demand of land for housing is higher than that of the available recognized land under the municipal authority; hence informal settlement patterns are becoming the usual trend especially towards ecologically sensitive boundaries of the town which is characterized by mountain hill sides, sloppy forest land and gully structures and the two river plains. As a result of deforestation and impermeable coverings by construction, the capacity of the natural land feature to infiltrate and percolate rain precipitation is decreasing from time to time with the subsequent increase in surface runoff conveyed to water bodies across drainages and urban storm ways. This trend of increase in surface runoff is featuring Sawla town by seasonal flooding calamity with a serious social, economic and environmental impact especially encountered by poor vulnerable communities. Therefore the purpose of this study is to assess seasonal flooding vulnerability, cause and impact in Sawla town by then suggesting feasible recommendation to mitigate the impact of seasonal flooding on the social, economic and environmental wellbeing of the town. A descriptive research type was employed to describe the cause and impacts of seasonal flooding on vulnerable communities of the town. Reliable data have been gathered from 163 (93% response rate) randomly selected respondents founded from four kebeles (Zirko, Botre, Kera and Kusti) of the town through questionnaire, interview and observation. Based on the data obtained from the field and secondary data sets, urbanization and informal settlement, deforestation, rainfall variability as climatic change and inadequacy of infrastructure are identified causes of seasonal flooding in the town. This seasonal flooding trend produced serious social, economic and environmental damages in Sawla town.
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I would like to thank first the Almighty God for giving me the strength to reach this far. Next I am grateful to Dr. Vikrant Tyagi for his time sacrificed, useful comments, frequent follow ups and suggestions throughout this academic work.
I am great full for my lovely wife, Ms Dhinet Abebe for being on my side in data collection and encoding as well as keying the main report of this thesis.
I would like to take this opportunity to express my sincere thanks to Sawla Town Administration and Sawla Town Municipality experts for providing necessary information and Sawla Town Officials for their kind cooperation during my field work.
I would like to express my special thanks to all my friends especially to Mr. Seid Aragaw and Getnet Syum for their multi-dimensional assistance from the beginning up to the end.
Finally, I would like to forward my great thanks to Mr. Amanuel tesfaye, Ms. Aster Chutulo and Mr. Yerukneh Awugichew for their invaluable assistance in data collection.
Climate change is one of the greatest environmental, social and economic threats faced by the planet. Climate change scenarios generally imply an increase in rainfall variability and, on global average, an increase in total precipitation, which could lead to even more frequent and severe natural disaster such as drought and floods (Elisabetta, 2006).
Floods are natural and seasonal phenomena that play an important environmental role. However, human settlements interfere with flood patterns, majoring their magnitude and frequency of occurrence, turning higher the associated level of risk regarding people, buildings and economic activities. Urban floods range from localized micro-drainage problems, inundating streets and troubling pedestrians and urban traffic, to major inundation of large portions of the cities, when both micro and macro-drainage fail to accomplish their basic functions (Miguez and Magalhaes, 2009). These can lead to material losses to buildings and their contents, damage to urban infrastructure and residential housing in a village.
This study focuses on seasonal flooding, impacts and responses to flood risk among the urban residents living in the highly vulnerable area of Sawla town and those living along the ‘ Womba and cholea’ river plains with in the town. It explores the underlying vulnerability of the area, impacts and challenges of how effectively to shape human and institutional responses to the risk of natural disasters with a special focus on seasonal floods.
Floods are natural disasters that have been affecting human lives since time immemorial. Throughout history, nature has shown little respect for man's unwise occupancy of nature's right-of-way and has insured that the message has been clearly understood by sporadically flooding people's properties and taking their lives. Flood are associated with some extreme natural events that happen on a geographical area known as a drainage basin, which is also referred to as a river basin, a catchment area or a watershed. Drainage basins can be rural (natural) and urban, the former commonly being much larger than the latter. Hence, flooding can be rural and urban (Andjelkovic, 2001).
In Ethiopia context, the rainy season is majorly precipitate within the four months between June and September when about 80% of the rains are received. Torrential down pours are common in most parts of the country. As the topography of the country is rather rugged with distinctly defined watercourses, large scale flooding is rare and limited to the lowland areas where major rivers cross to neighboring countries (Daniel, 2007)
The impacts of floods have long been recognized as complex and multifaceted. In Sawla town, flooding fatalities have been rare in recent decades, but financial damage to property, disruption to communications, public infrastructure damage and business losses have all featured though scholarly studies have not been undertaken yet.
Sawla town is divided in to two sub cities each have three kebeles under them and hence the town has six kebelas namly, Botre, Zirko, Mehal-ketema, Megenagna, Kera, and Kusti. In the town, seasonal floods and other enviromental problems are most frequently occurring on the urban pherifery where squatter settlers randomly and illegally settle on disaster prone areas due to unaffordable housing price. According to Sawla Town Municipality annual report, 2009 in addition to those who are settled on the urban periphery, parts of Botre, Zirko, Kera and Kusti kebeles which are located along the revere banks of ‘ Womba and Cholea’ river plain are mostly affected by overtoping river banks flooding year after year. This flood at times of unusually high rainy days over top the normal flood ways and create a lot of calamity to the residents of Sawla town as well as to the environment in the form of land slide, sediment deposition on water bodies, water stagnation for prolonged months causing community ill health and urban green damages. In the past several flood events occurred and caused a lot of distraction on properties and people resilience. This flood incidence has created a significant influence on the resilience of residents of Sawla town prevailing them in to restlessness due to the fear of disasters and the resultant loss. Therefore, the purpose of this study was an assessment of seasonal flooding and the resultant impact as well as coping strategies adopted in Sawla town there by producing scholarly strategic means of addressing this problem.
The general objective of the study is an assessment of seasonal flood impact and coping strategies in Sawla town.
The following are specific objectives of this study
- To determine flood vulnerable communities in Sawla town
- To assess causes of flooding in Sawla town
- To forward recommendations to mitigate flood problems in Sawla town.
The following are major research questions that were used to achieve the research objectives up on the accomplishment of the study
- What are vulnerable parts of the town?
- What are impacts of flood in Sawla town
- What are main factors causing seasonal flooding in Sawla town?
- What are coping strategies that were undertaken by the community during flood emergency?
- What are possible means of addressing flood problems?
Urban flooding leads to different impacts including social, economic and environmental disruptions. However, limited studies exist in Sawla Town on the vulnerability and impacts of floods on vulnerable urban residents who are settlers of ecologically sensitive parts of the town especially along the river banks of ‘ Womba and Cholea’. Hence there is a huge knowledge gap on the causes and impacts of flooding in the town. This study intended to fill this knowledge gap in a way to mitigate flood related problems at the municipal level. Thus the study is contributory to different levels of government in the town and to make sound decisions on urban flooding related issues. The town administration benefits from the study because, the study provides them information with regard to flood vulnerability and the resultant impact which helps them to evaluate the environmental disaster planning, preparedness and emergency mitigation programs, policies and strategies.
The scope of the study is delimited to Sawla Town Administration and the surrounding where a flood incidence most frequently occurs. From the six administrative unites of the Town four kebeles were studied. The scope of the study therefore covered the locality of the town and its surrounding where the problem of flooding is frequent leading community members to displace from their permanent residential places and losses of properties.
Sawla town is situated in Southern Nation’s Nationalities and People’s Regional States within Gamo Gofa Zona administration. It is 518 km from Addis Ababa, 305km from Hwassa (regional capital) and 253 km from Arbaminch (Zonal capital). Astronomically it is located in 6047’50” North latitude and 360 52’ 50” east longitude directions and with an average elevation of 1410 meter above sea level (Bharu, 2011). It is located on south facing slop of Mountain Weyla which is 2394 meter above sea level, the east facing slop of Dakishu Subo mountain range (2220 meter above sea level) and Duza hill (1411 meter above sea level) as a result the study area is sloping and highly dissected by mountain streams (NUPI, 2002 cited in Baharu,2011 ). Therefore, Sawla town structure and the nature of location are highly exposed to seasonal flooding with varying intensity on different parts of the town.
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Source: Sawla Town administration office, 2012
According to the result of 2007 population and housing census the total population of Sawla town were 22,702 of which 11,485 and 11,217 in Bola sub-city and Yocha sub-city respectively in both sexes. The total number of households was 5,869 of which 3038 were in Bola Sawla sub- city and 2831 were in Yocha Sawla sub-city (CSA, 2010). According to Sawla Town Finance and Economic Development Office 2012 the population of Sawla is projected to be 28,704 by 2012 and the household’s number is 10063
This part of the research presents the review of related literatures on the concept and definition of urban flooding, cause and social and economic impacts of urban flooding. Literatures was reviewed in order to provide the study with conceptual framework to explain theories underling the study to further define the problem and thereby to identify previous research studies on the causes, impacts and coping strategies of urban flooding.
Flood: According to Acreman, 2000, the common definition of a flood is “the inundation of normally dry land”. On many river systems, there is a sharp divide between a well-defined river channel and adjacent flat land (the floodplain). Flooding normally occurs when flow in the river exceeds the capacity of the channel and water spills onto the floodplains.
Seasonal flooding - In some areas, flooding is an annual occurrence and is expected. Seasonal flooding like thus took place every summer for thousands of years along the Nile River in Egypt. The monsoons caused hard rains at the source of the river which filled the river channel to overflowing (World Geography, 2010). Therefore seasonal flooding is an event of flooding due to seasonal rain fall.
Urban Flood: A phrase used to specifically speak of flooding caused or situation made worse by human activity such as the land being converted from fields or woodlands to roads and parking lots. The land loses its ability to absorb rainfall. Urbanization increases runoff 2 to 6 times over what would occur on natural terrain. During periods of urban flooding, streets can become swift moving rivers, while basements can become death traps as they fill with water (Wikipedia, 2010).
River Flooding: Occurs when the river waters flow outside the river channel or when the water flow over the river banks. This is a natural and inevitable part of life along a river. Some river flooding is seasonal when annual rains fill river basins with too much water, too quickly. Torrential rains from decaying hurricanes or tropical systems can also produce river flooding (Callahan, n.d)
Vulnerability - is the set of conditions and processes that determine both the likelihood of exposure and resulting susceptibility of individuals and social systems to the hazard.
Werritty et al, 2007 study’s cited in Few, 2006, defines vulnerability in the context of floods as: “a set of conditions and processes that determine the likelihood of exposure and the resulting susceptibility of humans or human systems to the adverse effects of a flood hazard.”
Coping capacity - is the ability of individuals and groups both to avoid exposure to hazard and to tolerate and recover from the adverse effects when that hazard becomes a disaster (Werritty et al, 2007 cited in Handmer, 2003; White et al., 2004; Few, 2006).
Floods are caused by numerous environmental, seasonal and human factors. All flooding can be dangerous and potentially deadly, although infrastructure and property damage are among the most common outcomes. Despite the fact that large-scale floods are generally thought of as the most dangerous, smaller floods and flash floods can cause much harm as well. As little as two feet of running flood water can sweep away a large automobile and drown a person swept up in its currents (Callahan, n.d)
Urbanization is one of the most typical land use process, and it affected deeply to the mechanism of water circle in towns, including rainfall-runoff process (Hongjian, et al, 2007). This change allowed natural systems to become more volatile and the probability of extreme events such as flood and drought to become increased. Urbanization generally increases the size and frequency of floods and may expose communities to increasing flood hazards. Streams are fed by runoff from rainfall moving as overland or subsurface flow. Floods occur when large volumes of runoff flow quickly into streams and rivers. The peak discharge of a flood is influenced by many factors, including the intensity and duration of storms and snowmelt, the topography and geology of stream basins, vegetation, and the hydrologic conditions preceding storm and snowmelt events (U.S. Geological Survey, 2005). In this respect land use and other human activities influence the peak discharge of floods by modifying how rainfall water stored on and run off the land surface into streams. In undeveloped areas such as forests and grasslands, rainfall and snowmelt collect and are stored by vegetation, in the soil column, or in surface depressions. When this storage capacity is filled, runoff flows slowly through soil as subsurface flow. In contrast, urban land covers are often refered as "hard scapes" in opposition to natural land covers or "soft scapes". Since hardscapes are composed of impervious surfaces, they avoid the water drainage into the subjacent soil. Furthermore, subjacent natural soils can also be highly impervious because of the compactness introduced by urban development (Marco and Camilo, 2010). Construction of roads and buildings in urban areas often involves removing vegetation, soil, and depressions from the land surface. The permeable soil is replaced by impermeable surfaces such as roads, roofs, parking lots, and sidewalks that store little water, reduce infiltration of water into the ground, and accelerate runoff to ditches and streams. Even in suburban areas, where lawns and other permeable landscaping may be common therefore, rainfall and snowmelt can saturate thin soils and produce overland flow, which runs off quickly.
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Fig 2.1 Source Tucci, (2007): Water balance characteristics in an urban watershed. During pre urbanization the green cover very significant thus provides multi-purpose benefits with regard to hydrological cycles. This means that as shown on the above figure of 100% rain precipitation 40% will be taken by the process of evapotranspiration which is physiological process of green plants. The remaining 10% and 50% will go through surface runoff and underground water respectively. Therefore surface runoff accounts for insignificant percentage as a result of which chance of flooding is very narrow in green covered and permeable natural land. On the contrary, when urbanization occurs deforestation is followed by impermeable pavements and house construction which disrupts the natural hydrological cycle. In urban condition of 100% rain precipitation only 25% will be evapotranspired because of deforestation and the surface runoff will be triple of during pre-urbanization (30%) and additionally surface runoff from roofs are created accounting for 15% hence rain water drainage accounting for 45% which is significantly enough for inundating the urban areas. The remaining 30 % will be taken in to ground water.
Table2. 1 . Urbanization impacts over flooding
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Forest soil generally have infiltration and surface storage capacity that exceeds the intensity of most rainfall events and therefore over land storm flow is infrequent. When it occurs most surface run-off is generated where rainfall on saturated soil or impervious surface such as rock out cropping. Saturated soils in and near stream channels and wetland produce the first storm flow. As the storm continues, rain infiltrates and percolates to fill soil storage and the saturated area expands up the stream banks and to intermittent and ephemeral channels (Vince, et al, 2005). Therefore, deforestation is among human induced factor for flooding.
Changes in climate and atmospheric systems of relevance to floods embrace: precipitation (intensity, volume, timing, phase – rain or snow), air temperature (controlling snowmelt and ice-jam), seasonality and climate variability (Kundzewicz, 2008). Changes in the frequency of heavy rainfall events can arise from several causes, e.g., changes in atmospheric moisture or circulation. There is now scientific consensus that the global climate is changing. Global mean temperature increased by 0.6 degree C in the last century, with the hottest years ever in record occurring after 1990. This warming of the world climate has been linked to a higher concentration of greenhouse gases (GHGs) in the atmosphere, the consequences of which can be manifested in the higher frequency of extremes such as floods, droughts and cyclones (UNEP,2006a).
Table 2 .2 Natural and human factors of urban flooding related to climate change
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Source: World Meteorological Organization (2008)
Many of the impacts associated with climate change exacerbate or alter existing hydro meteorological hazards, such as droughts, floods, storms and heat waves (Chain etal, 2010). Intergovernmental Panel on Climate Change (UNEP, 2006 cited in IPCC) concluded that, the majority of warming over the past 50 years is likely the result of human activities there by rising sea level and accelerated hydrologic cycle resulting in greater precipitation, and a potential increase in climate variability, such as extremes of precipitation and storm activity. The reasons for the increased flood hazard are several and correlated. Potential climate changes are expected to cause a rise in the frequency as well as the intensity of rainfall, which may lead to more widespread and severe natural disaster (Elisabetta, 2006).
Sherbinin, et al, 2007 described Vulnerability as the degree to which a system or unit is likely to experience harm due to exposure to perturbations or stress. The concept of vulnerability originated in research communities on examining risks and hazards, climate impacts, and resilience. It is the vulnerability of the community at risk that determines the extent of the flood disasters (APFM, 2004). Thus vulnerability is caused by a combination of physical factors such as exposure to floods, degree of protection from flood hazards, quality of infrastructure available, degree of access to resources, and ability to avoid, withstand or recover from the flood hazards. Socio-economic factors like acute poverty, high population density, poor emergency planning and lack of technical options to cope with the situation increases the vulnerability of the population to floods.
A literature review of vulnerability studies (De Graaf, 2008 cited in Graaf et al., 2007) shows that, vulnerability can be considered as a combination of threshold capacity, coping capacity, recovery capacity and adapting capacity.
Threshold capacity: Threshold capacity is the ability of a society to build up a threshold against variation in order to prevent damage. In flood risk management, examples are building river dikes and increasing flow capacity to set a threshold against high river flow. The objective of building threshold capacity is prevention of damage. The time horizon lies in the past; past disaster experiences of society are the guiding principle to determine the height of the threshold.
Coping capacity: Coping capacity is the capacity of society to reduce damage in case of a disturbance that exceeds the damage threshold. Coping capacity of society is determined by the presence of effective emergency and evacuation plans, the availability of damage reducing measures, a communication plan to create risk awareness among residents, and a clear organizational structure and responsibility for disaster management. The objective of developing coping capacity is reduction of damage. The time orientation is instantaneous, because in case of emergencies, only ‘here and now’ is important.
Recovery capacity: Recovery capacity is the third component and refers to the capacity of a society to recover to the same or an equivalent state as before the emergency. It is the capacity of a flooded area to reconstruct buildings, infrastructure and dikes. The objective of developing and increasing recovery capacity is to quickly and effectively respond after a disaster.
Adaptive capacity: Adaptive capacity is the capacity of a nation, a community living near to river basin, or even the world to cope with, and adjust to uncertain future developments and catastrophic, not frequently occurring disturbances such as extreme floods. Although a system may be functioning well at present, human and environmental developments, both from inside or outside the considered system, can put a system under strain and threaten its future functioning.
Flooding is one of the common hazards that causes loss of life and properties of people and even causes severe economic set back, especially in developing countries. According to Anggraini, 2007 defining flood impact would rather difficult, partly because of the fact that floods complex phenomena and partly because they are viewed differently by different people in effect. In fact the impact of flooding can be social, economic and environmental providing the degree and severity depends on the scale and type of flood. The loss of flooding is categorized in to direct and indirect. According to World Meteorological Organization, 2008, direct losses are resulting from direct contact with flood water, to buildings and infrastructure while indirect losses are resulting from the event but not from its direct impact, for example, transport disruption, business losses that can’t be made up and losses of family income. In both loss categories, there are two clear sub-categories of loss which are tangible losses and intangible losses, tangible losses are loss of things that have a monetary (replacement) value, for example, buildings, livestock and infrastructure. Intangible losses are loss of things that cannot be bought and sold, for example, lives, injuries and heritage items. On this study flood damage and losses (direct or indirect) are considered as the impact of seasonal flooding.
Any natural disaster has a consequence of both tangible and intangible losses both economically and socially. When urban flooding occurs, considerable damage to Public buildings, Public utility works, housing and household assets is common. Loss of earning in industry and trade, loss of earning to petty shopkeepers and workers , loss of employment to daily earners , loss of revenue due to road, railway and transportation interruption are among those of urban flooding economic impacts.
According to Werritty et al, 2007, the social disruption caused by floods can seriously undermine the quality of life of individuals and impact on the fabric of affected communities. The psychological impact of the emergency and aftermath causes longer term effects that may be exacerbated by stresses such as having to move out of the home, cleaning up, negotiating with insurers and getting damage repaired and goods replaced. Even when the ‘recovery’ phase is over, there may be difficulties caused by living with the ongoing risk, obtaining and paying for insurance and the effect on house prices.
Impervious surfaces are environmental concerns because chains of events are initiated modifying urban air and water resource. The pavement materials seal the soil surface eliminating rain water infiltration and natural ground water recharge. Citing a recent article in the Seattle time’s journal, Marco and Camilo, 2010 indicated that, while urban areas cover only 3% of the US, it is estimated that, their runoff is primary source of pollution in 13% of rivers, 18% of lakes and 32% of estuaries. Urban flooding is responsible for an alarming increase of pollution in the nature’s water bodies. Anjelcovy 2001 stated that, storm water runoff may contain organic wastes, nitrites, bacterium, suspended solids, heavy metals, oils, animal wastes, tire and vehicle exhausts residues, de-icing chemicals street liters and sediments from construction sites with resultant effect on water bodies and aquatic ecosystems.
Coping strategies are often complex depend on the assumption that an event will follow a familiar pattern, and that actions that were taken before to cope are a reasonable guide for similar events (Jabeen, et al ,2009 cited in Wisner et al. 2004). They operate within different scales like, individual level (household), community level (e.g. neighborhood) or institutional (e.g. city-wide or beyond). According to UNFCCC, 2004 coping strategies take different forms at different levels the following are some of them.
1. Preventative strategies – at the individual and small group level means people making choices so that they will not be affected by an event, such as avoiding dangerous places at certain times or choosing safe residential locations.
2. Impact minimizing strategies – These are strategies to minimize loss and to facilitate recovery in the event of a loss. This is generally referred to as ‘mitigation’ in disaster literature, but ‘adaptation’ in climate change literature.
3. Diversifying income sources: Having more than one, or sometimes several, income earners in the family allows for diversification. If families have contributed to savings groups, this can offer a form of income during hard times.
4. Development of social support networks: This is the ability to call on the resources of others during difficult times. Networks can be within the household, between extended family members, within neighborhoods, and with wider groups who have a shared identity (religious, geographic, commercial, and others).
According to Andjelkovic, 2001 flooding has different aspects which include the climatic, social, economic and technical aspects. In that, the climatic of flooding deals with the climatic conditions that may lead to the occurrence of floods. In urban conditions, short and intensive showers proved to be just as critical as long lasting rains, but in rural conditions long lasting rains over an area-wide territory, accompanied with snow melting in the river basin, are recognized as possibly more influential. The social aspect of flooding deals with the way the floods occur in different settings. In urban conditions, one can negotiate the intensity and frequency of the disruption of public life and traffic, whereas in regional conditions the common term is disaster, although there were many situations where local urban flooding had disastrous consequences such as property and life loss. However, floods do not necessarily always need to be associated with devastating consequences. The economics of flooding deals with the issues of financing the capital improvement, operation, and maintenance of flood protection schemes. Local storm water drainage and flood protection is usually financed by local revenues, such as local taxation, service fee, or user charge fee, collected on the basis of land use, whereas the regional protection is mostly carried out through general taxation.
The institutions responsible to avoid impact of flooding deals with the role of governments in the process of decision making regarding flooding events and to some extent linked to the economic aspect.
Technical issues of flooding deals with the concepts and works usually applied in flood protection. In urban conditions, the "dual drainage" concept is most commonly applied, introducing the distinction between the storm water drainage service and urban flood protection, whereas in area-wide conditions flood control measures are always regarded as a part of the regional or state-wide flood control schemes. On the other hand according to Tucci (n.d), the main aspects of urban drainage and flood control management in developing countries of humid tropics are: climate, urban development and institutional aspects. Technical tools and principles of urban drainage control are well known in developed countries but their direct application in the developing countries has not been successful. They require some adaptation to the conditions of each country.
Planning and management actions can increase the resiliency and adaptability of water systems in the face of expected climate change. Proactive options use robust methods for risk management in water resources, and help insure cost-effective responses to climate change (Easterling, etal, 2004). Urban floods as an outcome of global and local climate change cannot be managed in isolation at the city scale and responses to potential flood impacts are complicated by interlinked political, socio-economic and environmental changes (Zevenbergen et al, 2008). Therefore, to manage effectively and for proactive decision making a framework should be developed in which spatial and temporal relations are further defined and investigated in a fashion of understand the unique features of urban flood management. This should provide clarity regarding both the feedback loops that cause vulnerability as well as those that build resilience.
A number of researches related to urban drainage management had recognized that, current control of urban runoff in developing countries has been established on an incorrect basis, causing serious harm to the population. According to Tucci, (2006), these adverse impacts have been caused principally by two kinds of error: 1. Drainage design principle in which urban drainage has been developed on the basis of the incorrect principle that, the best drainage system is one that carries the excess water as quickly as possible away from its place of origin and, 2. Evaluation and control in sections: on the assumption that, Micro drainage designs increase flow and transfer all their volume downstream. In Macro drainage, urban drainage tends to be controlled by canalizing the critical sections. This type of solution is based on the particular perspective of a section of the watershed, without taking account of the consequences for the other sections or other aspects of urban settlement. Canalizing the critical points only transfers the flooding from one place to another in the watershed. Principally with the necessary commitment by technical staff, it is possible to identify the combinations of runoff transfer and attenuation without transferring impacts downstream. The important thing is not to get too attached to a preconceived idea, but to look for a combined solution, based on the fundamental principle that no project may transfer its impact to another point in the watershed.
According to the survy study conducted by Werritty et al, 2007, in Scotland rivers over topping their banks were the most common cause of flooding followed by surcharging sewers and overland flow and coastal storms respectively. Hence in Scotland, people who are settlers of near and/or around the river plain and poor with inappropriate, aged and inadequate sewer systems are the most vulnerable part of the society to flood problems.
Coping strategies- The most common immediate responses to a warning in the Scotland were to remove possessions from the ground floor, deploy sandbags or flood guards, move vehicles and vacate the property. Neighbors and friends provided most of the emergency assistance with local authority and Fire Service staff.
Acording to the case study made by Jabeen,et al 2009, in general is vulnerable to climate variability and climate change because of its geomorphologic location. The capital city Dhaka has experienced 9 major floods in the last 55 years among which incidences of 1988, 1998 and 2004 were severe due to overflowing of surrounding rivers. The case study finded that , facts of climate change are not evident phenomenon for the inhabitants of Korail in Bangladesh rather they recognize the climate variability. They suffer from water clogging and flooding in regular monsoon as well as untimely rainfall. In addition to physical impacts the vulnerability increases through unsecured livelihoods, increased health risks and constrained economic activities.
C oping S trategies of Korail, Dhaka
Phiscal coping strategies- The study shows that, in Korail choosing safe location to avoid danger is not an option for most of the squatters, as option of building new rooms are now only possible through encroachment of water edges susceptible to flooding. In that sense most of the households take few preventive actions before any disaster as a recognised measure of coping strategy.
Economic strategies - Savings is seen as a main coping strategy for most of the households. 50% household saves regularly with savings groups or NGO with an intention that they can take loan from their savings during and after any disaster.
Social networks and safety-net s-The inhabitants of Korail have a very strong social network. It has a strong community based activities which prevented eviction in number of instances
A case study made by India Meteorological Department 2009 adopted that, the most devastating urban flood in India occurred in 2005 in Mumbai when historic highest rainfall of 944mm in 24 hr occurred along with high tide of 4.48m. Because of the inadequate Storm Water Drainage capacity and heavy rains, Urban Floods is an annual feature of Mumbai disrupting rail and road traffic, flooding of slums and low lying areas, collapse of old structures practically halting all the activities.
Proactive measurs taken : Maintenance of drainage system in order to avoid flooding and water logging. Structural Measures by Mumbai Municipal Corporation had been undertaken revamping the system by changing of design of the drainage system. Flood Warning Systems was another measur in which Mumbai Municipal Corporation, India Meteorological department and Ntional disaster management Authority jointly had prepared warning system by installing 35 automatic raingaige stations.
According to Ethiopian early warning system agency 2007, Flash floods and seasonal river floods are becoming increasingly common due to deforestation, land degradation, increasing climate variability, and settlement patterns. During the past two decades, major floods in 1988, 1993, 1994, 1995, 1996 and 2006 have caused significant loss of life and property. Large-scale flooding is limited to the lowland areas of the country however, intense rainfall in the Highlands causes flooding of settlements in a number of river basins, particularly the Awash River Basin in the Rift Valley. Annual flooding in urban areas, especially in Addis Ababa, causes property damage along streams descending from the nearby hills. Flash floods are common in most parts of the country, especially when rains occur following prolonged dry spells.
According to DMFSS, 2009, Ethiopia’s institutional framework for disaster risk management has undergone numerous changes in mandate, structure, and scope over the past 30 years . Following the devastating 1973/4 famines in Northern Ethiopia, the Relief and Rehabilitation Commission (RRC) was established. During its 20-year existence, RRC focused on disaster response and the distribution of relief supplies. The ratification of the National Policy on Disaster Prevention and Preparedness Management (NPDPM) in 1993 led to a shift in thinking based on the perceived need to more closely link the relief and development agendas. With this in mind, the government restructured RRC to establish the Disaster Prevention and Preparedness Commission (DPPC), and gave it a mandate to focus on the links between relief and development.
Laws and proclamations
According to UNCED, 2002, in Ethiopia, the National Meteorological Services Agency (NMSA), by virtue of Proclamation No. 201 of 1980, is entrusted with the monitoring of the atmosphere, including the provision of meteorological and climatologic services. NMSA is also mandated to coordinate issues of climate change and ozone layer depletion. Ethiopia ratified the UNFCCC on 5 April 1994. An ad-hoc committee, the National Climate Change Steering Committee, composed of representatives from governmental, non-governmental, and academic/research institutions has been formed in 1998 to oversee the implementation of the UNFCC. However, the operation is not well recognized in coverage at local government rather hanged at national and regional level.
The Ethiopian Water Resources Policy was approved in 1999. The policy covers aquatic resources, aquatic environments, watershed management, water resources protection and conservation, water quality management, integrated water supply and sanitation, and irrigation for hydropower generation.
The Water Resources Proclamation was enacted in 2000. The Water Sector Strategy mainly aims at improving the overall management of the country’s water resources and supports the sustainable development of the water sector. Yet it is not regarded on flooding matters with certain specification. Ethiopia Disaster Risk Management (DRM) Plan mandated for Disaster Management and Food Security Sector (DMFSS) to shift from a focus on ex-post emergency response and relief work to the much broader ex-ante disaster risk reduction.
Figure 2.2 Institutional Frameworks for Establishing National Flood Management Centre (NMFC) of Ethiopia.
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Source: Moges, S.A (2007)
The above institutional framework illustrates that, the issue of flooding is concentrated at national; hence this will lag the work flow and efficiency to respond and mitigate localized flooding emergencies unless the frame is networked and institutionalized even at local government level.
In general Ethiopia has no special policy and proclamation particularly concerned on issues of flooding but flooding issues may be included under other environmental policies like water resource policy and DMFSS and Disaster Prevention and Preparedness Agencies. These policies and proclamations act on higher level emergencies at national level like Dre Dawa and Omo flooding disasters and at the local government level the coverage is very weak.
This part shows methods that were used in this study, procedures in deciding the sample design, data collection methods and methods of data analysis and presentation. A descriptive type of study was used to describe the characteristics of variables under the study. This researcher has employed both probability and non-probability sampling methods to draw representative sample from the total population. Open ended and close-ended questionnaires, structured and non-structured interview and observations were made to collect firsthand information regarding flood incidence and coping strategies adopted by the community to assess seasonal flooding impact and coping strategies in Sawla town.
Both Qualitative and Quantitative research approaches was used by the researcher. A mixed approach or triangulation is effective in observing multifarious aspects of variables of the study as variables were measured both qualitatively and quantitatively after operationalization.
For this study the researcher used a descriptive type of research method to describe the characteristics of flooding impacts and coping strategies in the study area. Descriptive type of research method is relevant for the researcher to describe causes of seasonal flooding and its impacts as well as coping strategies adopted in response to the emergency in Sawla Town.
Questionnaire - Questionnaire was prepared in both open ended and closed ended forms and was administered to sample respondents. In order to enhance communication and to have reliable data questionnaires were prepared in English and the native language.
Interview - Interviews were scheduled with officials and town administrations, workers of municipality and households which are living in the study areas.
Observations- These were done in selected parts of the town particularly along sides of river banks in order to broaden the knowledge of causes and impacts of seasonal flooding in Sawla Town to have scholarly understanding on addresing these problems at the end.
This research had used both probability-sampling and non-probability sampling techniques. The probability sampling technique was utilized in selecting sample units and the way of selecting sample elements was simple random sampling in which households in each kebeles were listed independently as a sampling frame by giving them numbers for each households according to their list then picking each units randomly and counting until it reaches the sample size determined. The non-random sampling technique was used for the second unit of analysis which were, the Mayor of the town, senior officials of the town administration, municipality employees and sub city officials.
According to the result of 2007 population and housing census, the total population of Sawla town was 22,704 in both sexes and the total number of households was 3038 in Bola Sawla sub- city and 2831 in Yocha Sawla sub-city. On the contrary according to Sawla Town Finance and Economic Development Office (STFEDO) 2012 the population of Sawla is projected to be 28,704 by 2012 and the household’s number is 10063. This is the target universe population of this study.
The sampling frame was lists of households of each administrative unit. Among the total six kebeles four kebeles, two from Bola Sawla namely Zirko and Kust kebeles and two from Yocha Sawla namely Botre and Kera kebeles which were purposively selected based on the experience of flood emergencies.
The sample unit was households of selected four kebeles, the Mayor of the town, manager of the municipality, higher officials of the town administration and municipal officials of both sub-cities.
Survey sample: The researcher was focused on the four kebeles from the six kebeles that had been impacted by the seasonal flooding and the respondents were identified due to their residency in the impacted and risk prone location. A random sample was drawn from households within that area.
Qualitative interview sample: Qualitative interviews were performed through non-probability sampling. Initial informants were identified purposively through faith government institutions located in the study area. These were the mayor, municipal managers, higher officials of the town administration and municipal officials.
To select the sample size from Sawla town of the selected administrative unites, the researcher employed the following formula (Kothari, 1995) as: n=Z2×p×q÷(d2)
Where, n= the desired sample size, Z= the two tailed limit with 93% confidence level (1.81), P= the proportion in the target population (0.5) and q= 1-P
d= Sample error because of absence of previous studies and time limitation.
The result is, n= (1.81)2×(0.5)×(0.5)/(0.07)2 those, n= 167
But the total number of households is less than 10,000, the formula is therefore,
f(n)= n/(1+n/N) = 167/(1+167/6506) = 162.82 which is nearly equal to 163
Totally 163 respondents were selected from Sawla town to do this research but out of which 151 households has responded properly and these are 32 from Botre, 52 from Kusti, 15 from Kera and 52 from Zirko kebele while the intended sample size was as shown on the table blow. In addition purposively 4 expert of the municipality, 1 mayor of the town, 1 manager of the municipality, 2 senior officials of the town administration and 4 sub-city officials (two from each of the two sub-cities). In order to balance the chance of involvement, the percentage share of each kebeles were used in the sample population. Percentage ratio of each kebeles from total 6506 (STFEDO, 2012) sample population was identified as follows;
Table 3 .1 Sampling distribution
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Primary Data Sources: Primary data was obtained through distribution of structured questionnaire to informants, observation of the existing situation and structured interview were conducted to collect the information.
Secondary Data Sources For the secondary data, sources include relevant books and literatures, previous researches, Internet sources, unpublished materials and other related documents including policies and legislations were used.
In analyzing the data, both qualitative and quantitative data analysis employed depending on the nature of the data collected. The quantitative data was analyzed and interpreted using percentage, graphs, tables and narrative discussions. The qualitative data were analyzed and interpreted by using photographs (plats). After checking the data collected from the sampled households, municipality officials, the mayor and senior administration officials of the town, respondent’s data matrix was prepared then the data was coded and filled in SPSS and Ms-Excel was also used for some constructive summery.
Wissenschaftliche Studie, 38 Seiten
Doktorarbeit / Dissertation, 263 Seiten
Wissenschaftliche Studie, 95 Seiten
Wissenschaftlicher Aufsatz, 44 Seiten
Hausarbeit, 12 Seiten
Seminararbeit, 13 Seiten
Akademische Arbeit, 18 Seiten
Projektarbeit, 15 Seiten
Seminararbeit, 49 Seiten
Hausarbeit (Hauptseminar), 19 Seiten
Masterarbeit, 90 Seiten
Wissenschaftliche Studie, 38 Seiten
Doktorarbeit / Dissertation, 263 Seiten
Wissenschaftliche Studie, 95 Seiten
Wissenschaftlicher Aufsatz, 44 Seiten
Hausarbeit, 12 Seiten
Seminararbeit, 13 Seiten
Akademische Arbeit, 18 Seiten
Projektarbeit, 15 Seiten
Masterarbeit, 90 Seiten
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