Effect of Land Use on Flood Resilience

Jing LI, Shaoyu TONG

Institute of Land Resources and Sustainable Development, Yunnan University of Finance and Economics, Kunming 650221, China

Abstract This paper intends to study the internal and external influencing factors and restrictive factors of the post-disaster recovery capacity of the affected areas after the agricultural land is destroyed by floods. On the basis of summarizing the research results of the resilience of cultivated land damaged by flood at home and abroad, this paper analyzes the internal and external driving forces of flood resilience, and comprehensively analyzes the utilization pattern of cultivated land with different resilience. The post-flood recovery assessment is studied from the perspective of land use, and the results show that there is a negative correlation between flood resilience and agricultural fragility in this area. The main factors that affect the resilience of agricultural flood in a certain area are relative height, precipitation, the distribution density of rivers in the region, the proportion of agricultural population in the local labor force, the proportion of people enjoying the minimum living allowances in the region, the proportion of the elderly population, medical and health institutions and other kinds of infrastructure, per capita GDP. The main factors affecting the resilience of regional agricultural flood are analyzed and evaluated, and the corresponding measures are put forward.

Key words Flood, Resilience, Land use, Vulnerability, Evaluation

1 Introduction

Global natural disasters have always been the focus of attention, in which the damage caused by floods to agricultural production is tremendous and far-reaching[1]. Land is the survival resource for any nation and country, the most basic carrier of agricultural production and the space of human production and life. The natural, agricultural, economic and social development of the region lies largely in the way and status of land use[2]. From the perspective of land use, the maximum reduction of agricultural economic losses and disaster recovery capacity (flood resilience) caused by floods has become an important factor in regional sustainable development. Facing great pressure and difficulties, regional agricultural production should maintain its own operation and cope with a variety of changes, which has become a problem of great significance. Under this premise, the concept of flood resilience has gradually become an important research object to promote sustainable development. Resilience theory studies the ability of disaster-bearing bodies to cope with damage, change and post-disaster recovery, and provides a new way for regulating and managing natural resources. Some researchers at home and abroad believe that the study of resilience will be a reliable way to enhance the development of regional agricultural economy and promote sustainable development. Flood resilience, vulnerability and adaptability of disaster-bearing bodies are important components of the theme of regional environmental change. Kobe, Japan reached a consensus at the Second World Conference on Disaster Reduction in 2005 to strengthen the building of regional comprehensive disaster reduction capacity and achieve regional sustainable development.

At present, the study of resilience has developed from the initial study of ecology to the study of ecology, society and economy, especially the study of community. A community is an area with boundary characteristics that is inhabited by one or more residents living in groups. The community is the main body in the face of natural disasters, that is, the disaster-bearing body. By improving the scientific nature of land use, we can effectively enhance the flood resilience of disaster-bearing bodies, maintain the vitality of community agricultural economy, and improve the ability of sustainable development of the community. Land use is an important aspect that affects flood resilience, but there is not enough research on flood resilience from the perspective of land use by international and domestic scholars. Qualitative and quantitative analysis of the impact of land use on flood resilience can help human beings to formulate more scientific solutions and measures. This paper summarizes and reviews the current research on the relationship between land use and flood resilience at home and abroad, in order to provide reference for domestic flood resilience and agricultural sustainable development.

2 The research paradigm of the influence of land use on flood resilience

2.1 The conceptual origin of resilienceThe resilience theory originally comes from the study of ecology, which is used to evaluate and describe the ability of the ecosystem to face the disturbance of the external environment. Holling defines resilience as the ability of a community to remain in a special state in response to external natural disasters and changes[3]. The concept of resilience is a new concept in land science. According to the resilience theory, the community ecosystem will not be in a stable state all the time. If the community ecosystem changes from one state to another because of natural disasters, there will be a significant gap between the community ecosystem and the previous state. Therefore, the idea of natural disaster resilience regards this uncertain factor as a constant condition to study the adaptability and resilience of the community ecosystem. In the definition of the concept of resilience, domestic and foreign scholars have defined resilience from different angles. Generally speaking, the ability of the system to face external changes is defined as resilience. The concept of resilience has gone beyond the field of ecology, extended to natural resource management, adaptation to climate change, disaster management and other research fields.

2.2 Flood resilienceGreat progress has been made in the study of flood resilience in recent years. Reid[4]believes that community-scale measures, sustainability of production and personal income can affect the flood resilience and resistance of communities to floods. He found that the production activities of the community will adopt some production risk management and property protection in the face of floods, which can also reach the expected level. Harris[5]in his research elaborated the flood resilience after flooding caused economic losses to the agricultural industry in rural Australia. The methods of questionnaire survey and structural equation were used to study the impact of farmers’ response to flood on flood resilience. The results show that farmers’ personal sense of locality can affect community flood resilience. Kumming[6]proposed five factors that affect flood resilience. Through the comparative analysis of the community flood resilience of coastal cities such as Alexandria and Jakarta in the future climate change environment, it is concluded that social conditions, material, economic environment, natural environment and management science have a profound impact on the ability to resist disasters and flood resilience. The study of flood resilience has been valuable in disaster management and risk management, but the case study of flood resilience is still insufficient and lacking in objective and quantitative research methods. The practical significance of the study of flood resilience needs further research, and the measurement of the speed, time and level of flood resilience still needs to be explored.

2.3 Land useLand use is the combination of land and human labor, and the purpose is to create material products and provide services. The activity of land use is shown in land conversion, information exchange and energy use. Generally speaking, land use is a dynamic process. According to certain natural, economic and production purposes, as well as the natural characteristics of the land, people manage, transform and control the land in the region. Land use has two meanings: (i) The natural attribute of land use, such as vegetation condition, soil condition, and climate[7]. (ii) The economic and social attributes of land use. Land is the carrier of human production and life, and the damage of flood disaster to the disaster-bearing body is affected by the land use of this region to a great extent. The degree of land use spatial pattern and scientific use also has a great impact on the situation of flood and waterlogging disasters[8]. The vulnerability of disaster-bearing bodies is directly affected by the spatial distribution and proportion of land use types. According to the research of experts and scholars, the damage caused by flood and waterlogging is closely related to land use.

3 Analysis on the mechanism of the influence of land use on flood resilience

3.1 Conceptual definitionThe damage caused by the flood is closely related to the land use. On the one hand, flood water is stored when flooding is rampant, and the whole can be preserved at the expense of the part. On the other hand, agriculture in the region has to be developed, which forms the contradiction between agricultural production and flood discharge. Since China’s reform and opening up, the economy has developed rapidly, and under this background, the contradiction between agricultural production and flood discharge has become more intense, so it is necessary to strengthen the scientific nature of land use to alleviate this contradiction. In 1996, Hadmer introduced the concept of "resilience" into the category of disaster science, and then it was concerned and studied by many experts and scholars. Experts and scholars study flood resilience from different perspectives. Semmie[9]believes that flood resilience is the ability of communities to withstand the intensity of disasters when their quality of life remains relatively stable after they have been devastated by floods. In his research, Groffman[10]believes that flood resilience refers to the ability of the disaster-bearing body to recover to a normal level after a flood. Feng Jianfeng[11](2009) pointed out in his research report that flood resilience refers to the comprehensive embodiment of the administrative management of flood risk and the ability of economic compensation after the occurrence of flood. Zhou Hongjian and others use the method of mathematical statistics to analyze the current situation of land use in Dingcheng, Hunan Province, and the relationship between the current situation of local land use, the quality of agricultural population, the economic income and living standard of agricultural population and the resilience of natural disasters. Based on the views of the above experts and scholars, this paper holds that flood resilience can be defined as the ability of disaster-bearing bodies to continue to resist losses and restore normal production levels after flooding and causing damage to regional agricultural production. It has two implications: (i) The ability of farmers to recover their living standards after the flood, and to make use of the regional geographical conditions to make up for the damage caused by the flood, including the use of natural flood discharge capacity, as well as the construction of regional flood discharge infrastructure by the government and social groups. (ii) The self-recovery ability of crops after being damaged by floods and the effect of external forces (farmers and crops).

3.2 Influencing factorsWith the continuous in-depth study of land use science and flood resilience, experts continue to deepen the study of flood resilience and explore more ways to improve regional flood resilience. Land use affects regional flood resilience in many ways, which can be classified into three aspects: meteorology, underlying surface and society (Fig.1).

3.2.1Precipitation. Regional precipitation is a prerequisite for flooding, and an important factor causing flooding is heavy precipitation during the duration of the rainy season or during a period of time. A large amount of precipitation can directly affect the surface runoff. Both precipitation and rainfall intensity can determine the damage strength and resilience of the flood. For example, in 1996, the flood disaster in the Yangtze River basin lasted as long as 32 days; in 2007, there was 36-day torrential rain in China, and it was the longest flood with the heaviest rainfall since the 1990s.

Fig. 1 Evaluation index system of flood resilience

3.2.2Water system. The distribution of rivers, lakes and reservoirs in the region can have an impact on the resilience of regional floods. These factors have a direct effect on the flood resilience, that is, the flood resilience in the region is restricted by the distribution of rivers, lakes and reservoirs. The damage caused by the flood in a community is closely related to the distance between the community and the river, and the direction of the river is the main direction of flood flow. Generally speaking, the nearer to the river, the greater the degree of damage caused by the flood, and the farther away from the river, the more difficult it is for the flood to cause damage to it. According to the historical flood statistics, it can be concluded that most of the flood-prone points are in the areas along the mountain rivers, and the vicinity of the rivers is generally the first to be damaged by the flood. The density of the river network can reflect the overall situation of the underlying surface and the risk of damage caused by the flood. The greater the density of the river network is, the stronger the flood collection capacity is, and the less the flood permeates to the underlying surface. Where the rainfall is relatively heavy, the density of the river network will be relatively high, and the regional soil moisture will be relatively high. It is difficult for surface water to infiltrate downward, leading to the accumulation of surface floods, and thus a weaker resilience of agricultural floods in the region. At the same time, the flood impact of different rivers during the flood period is also different, the higher the level of the river, the greater the impact on the community, such as some main rivers (Jinsha River, Xiangjiang River,etc.).The lower the level of the river, the less impact on the community during the flood. For rivers at the same level in different geographical locations in different regions, the impact results are also different. As previously analyzed, river sections in low-lying plain areas can have a greater impact on flooding.

3.3.3Topography. Topography is an integral part of the formation of floods[12], and "water seeks its own level". Low-lying areas with relatively small flood discharge capacity are relatively more prone to flood disasters and there is relatively weak flood resilience. The topography not only affects the flood discharge capacity, but also affects the flood resilience in terms of precipitation. If it is on the windward slope, it is easy to form frontal rain. Moreover, the low-lying topography can easily lead to the convergence of surface runoff, and the surface runoff in the upstream also converges to the downstream. The plain and dam field are flat or low-lying, the surface runoff is slow, and the flood discharge capacity is weak. In addition, without the hindrance of topography, the flood spread is wide, and it is very easy to form floods, such as the plains of the middle and lower reaches of the Yangtze River, Kunming dam field in Yunnan, and Mengzi dam field. The probability of flood disaster in areas with relatively high terrain such as hills and mountains is significantly lower than that in areas with lower terrain such as plains and depressions. The formation of flood is not merely related to the height of the terrain, and the undulating terrain cannot be ignored. The flood discharge capacity of the places with large ups and downs is strong, and the flood is more difficult to accumulate. Where the terrain is relatively flat, the surface runoff is slow or even does not flow, the flood discharge capacity is poor, and the flood is easy to accumulate.

3.3.4Flood control works. At present, vulnerability can be divided into two aspects: first, the disaster-bearing body is directly affected by natural disasters; second, the disaster-bearing body also bears a series of indirect effects of disasters, such as the negative impact of natural disasters on the psychology of the working population. The construction of flood control projects such as dams and canals can strengthen the protection of river banks, prevent flood accumulation, and reduce the possibility of flood disasters on both sides of the river. Flood control project is an important index to measure the resilience of regional flood.

3.3.5The economic situation of the community. The population density in areas with relatively developed economy will be relatively high. Floods will do more damage to the region than places with relatively backward economies and low population density. During the flood period, agriculture is most affected by the flood. The industrial structure, buildings and resident population are the main structures of the disaster-bearing bodies. When they are damaged by the flood, the industry will be destroyed. Then the reduction in crop production leads to economic losses. The industrial scale of economically developed areas is larger and the value is higher. If the flood occurs, it will bring greater economic losses, so it will be more difficult to recover and the resilience of the flood will be weaker.

3.3.6The pattern of land use. With the development of human society, the degree of land transformation is getting greater and greater, the ways of land use are getting richer and richer, and new patterns of land use are constantly forming. Vegetation will change because of human activities, vegetation is an important factor in the disaster environment. For example, grasslands can accelerate the downward infiltration of surface floods in the natural environment. After the grassland is destroyed, the weakening of the downward permeability of the surface flood will also lead to disasters such as debris flow, which will seriously affect the flood resilience of agricultural production. The dense forest covered with vegetation can slow down the flood concentration and intercept rain water to reduce the destructive power of the flood. Thus it can be seen that different vegetation cover can reduce the destructive power of flood and enhance the resilience of flood in the region. Since the 20th century, floods have occurred more frequently than at any other time in history[13]. The more frequent human activities are, the more we should pay attention to the rational distribution of land use pattern in order to reduce the ability of vegetation to prevent flood disasters as much as possible.

4 Review of research on flood resilience

Flood has always been a topic worth studying in land use science, and some achievements have been made in the study of flood resilience in recent years. Generally speaking, most of the research on flood resilience is some case analysis on the basis of theoretical concepts and discussions. This paper discusses the effect of land use on flood resilience, and analyzes the internal mechanism of flood resilience according to the characteristics of different land and human transformation activities of land. (i) The theoretical model is an abstract description of the existing problems and extracts the operational features of the internal mechanism of the existing problems. At present, the research on flood resilience is still insufficient in qualitative and quantitative evaluation, and there are still some inconsistencies in the scope of the concept of flood resilience. The vulnerability and adaptability of disaster-bearing bodies need to be further studied. (ii) At present, there are relatively many researches on sudden natural disasters at home and abroad, such as earthquake, debris flow, tsunami, and typhoon. There is little research on chronic natural disasters, especially the damage of floods to agricultural industry. Agriculture is the most direct industry damaged by flood, and the degree of land use in the region also directly affects the damage of flood to agriculture. Strengthening the research on regional land use is helpful in improving the resilience of flood. (iii) The study of flood resilience lacks a unified standard in the selection of corresponding indexes, and the recognized and authoritative index system remains to be confirmed. When studying the resilience of flood in different regions, it is difficult to compare and analyze. Secondly, the selection range of some evaluation indexes is too large to be accurate to the community disaster-bearing body level. Finally, the weight of the dimensional level of the disaster-bearing body is also lacking in an effective evaluation system. (iv) Although some experts and scholars have analyzed some factors affecting flood resilience in theory and on-the-spot investigation, such as the perfection of community drainage system, and the degree of vegetation cover, most studies still put the influencing factors of flood resilience into one level. For the study of flood resilience, it is necessary to understand its internal mechanism from a more comprehensive and systematic perspective.

5 Conclusion

There are many factors that affect flood resilience, but the dependent variable indicators for us to obtain data directly are not rich. The difficulty of obtaining comprehensive basic data and insufficient research methods and innovation are also the reasons why the research progress of flood resilience is relatively slow at this stage. In accordance with the research results of scholars, we can draw the following conclusions: (i) The process of flood formation should be taken into account in the study of flood resilience, and the geological factors should be studied in order to analyze the flood formation process. The nature of the disaster-pregnant environment is mainly affected by geological factors. Due to the limited knowledge system, the study of geological factors is not deep enough, so it is necessary to use the knowledge of geology to study geological factors. In the future flood resilience research, it is necessary to improve the scientific nature of flood resilience research through interdisciplinary learning. (ii) Community economy is also a crucial factor in assessing flood resilience. When analyzing the element of community economic situation, due to the lack of relevant data, we can only directly refer to the average value of towns and villages in the region, so the accuracy of spatial distribution differences is affected. Therefore, in the future research, we should increase the data statistical work, refine the data units, and study the spatial distribution difference of flood resilience more deeply.