Flood Control Projects Research Articles

Analyzing the spatial scale effects of urban elements on urban flooding based on multiscale geographically weighted regression

In the context of rapid urbanization and the frequent occurrence of extreme rainfall in cities, the risk of flooding in the future will further increase, and the problem of urban flooding cannot be ignored. Urban elements exhibit significant spatial heterogeneity, which largely determines the spatial distribution differences in urban flooding. Therefore, it is important to clarify the scale of influence of different urban elements and explore their scale effects on urban flooding to accurately assess the risk of urban flooding. Taking Zhengzhou City, China, as the study area, this study analyzed the urban elements associated with urban flooding, quantified the scale of the influence of urban elements on flooding using multiscale geographically weighted regression (MGWR), and further explored the spatial scale effects of urban elements on urban flooding. The results showed that MGWR can better fit the spatially non-uniform distribution of urban flooding and that the scale of the influence of urban elements on urban flooding can be reflected by the bandwidth of MGWR. The results of MGWR indicated that the bandwidths of elevation, number of drainage outfalls (NDO1Abbreviations: RRP, Rainfall return period; DDR, Distance to river; NDO, Number of drainage outfalls; ILMFCP, Input level of materials for flood control projects; PRL, Proportion of residential land; PCL, Proportion of commercial land; PIL, Proportion of industrial land; PPSL, Proportion of public service land; PRA, Proportion of road area; PGL, Proportion of green land; PD, Population density; MI, Manpower input; GDP, Gross domestic product; ILER, Investment level in education and research.1), distance to river (DR), Gross domestic product (GDP), proportion of residential land (PRL), and proportion of commercial land (PCL) were small, and their influence scales were localized. In contrast, the influence of rainfall return period (RRP), slope, proportion of industrial land (PIL), proportion of public service land (PPSL), proportion of road area (PRA), proportion of green land (PGL), input level of materials for flood control projects (ILMFCP), population density (PD), manpower input (MI), and investment level in education and research (ILER) were at global scales. The most influential factors for urban flooding were RRP, PD, and MI. Slope, DR, and PRA had less influence on urban flooding. This study helps improve the effectiveness of urban flood prevention and mitigation efforts.

Impacts of River Network Connectivity on Flood Signatures and Severity Regulated by Flood Control Projects

The operation of hydraulic projects within plain river networks to mitigate floods can alter river network connectivity patterns, subsequently affecting flood processes. This study employed the MIKE 11 model to simulate flood processes under three different river network connectivity scenarios. Based on the simulations, we propose a method to evaluate flood intensity severity by integrating three flood characteristic indices: Slope of the Flow Duration Curve (SFDC), Rising Climb Index (RCI), and Flashiness Index (FI). These indices assess the overall magnitude of change, the rate of rise, and process fluctuations, respectively. Results indicate that changes in river network connectivity significantly impact RCI and SFDC, more than FI. Compared to the natural river network connectivity mode, changes in urban or watershed river network connectivity resulted in a significant decrease in RCI values by 3–37% or 18–38% across various return periods, with the rate of change in RCI values increasing as the return period lengthened. The impact of urban river network connectivity changes on SFDC within the Changzhou urban area was more pronounced under high-magnitude storm conditions, causing a 61% reduction. Furthermore, changes in watershed river network connectivity had a larger effect on SFDC under low-magnitude storm conditions than under high-intensity storms. Over 80% of the rivers under natural connectivity conditions exhibited flood intensity severity of Level III or higher, particularly in the Chenshu–Qingyang area. The alterations in connectivity significantly decreased flood intensity severity, with 85% to 91% of rivers showing the lowest flood intensity severity of Level I. Under a 100-year rainstorm scenario, flood risk shifted from within the flood protection envelope to outside it in the Changzhou urban area. The results will provide an important scientific basis for regional flood management in plains with dense rivers.

A systematic framework for assessing social vulnerability to flood for integrated flood risk management: A case study in Metro Manila, Philippines

Assessing social vulnerability to floods (SVF) is a crucial component of integrated flood risk management, especially in flood-prone regions such as Metro Manila in the Philippines. This study presents a holistic framework to assess SVF, based on susceptibility, exposure, and resilience factors while recognizing its multi-dimensional, multi-attribute, and context-dependent nature. The assessment was applied to three cities of Metro Manila: Marikina, Parañaque, and Manila. Indicators were systematically identified using deductive and hierarchical approaches, and factor indices were derived using a combined Simple Additive Weighting and Analytic Hierarchy Process, while the SVF index was estimated using the vulnerability relationship of the factors. The results exhibit a strong positive correlation with historical social flood damages and robustness across weight and normalization variations, with Marikina being the most vulnerable, followed by Parañaque and Manila. The city-level vulnerability profiles highlight salient determinants such as high population exposure in Parañaque, a relatively high population of susceptible social groups in Marikina, and significant disparity in flood control projects among the cities. Scenario analyses underscore the efficacy of flood countermeasures that reduce exposure and increase resilience. This study offers valuable insights and practical guidance for developing effective disaster reduction plans and policies in the study areas and similar regions by identifying disparities in vulnerability and understanding local conditions and drivers.

Sustainable flood control strategies under extreme rainfall: Allocation of flood drainage rights in the middle and lower reaches of the yellow river based on a new decision-making framework

Climate change has exacerbated the frequency and magnitude of extreme rainfall, which has led to the perpetuation of flooding as a hazard to humans and society. China has begun to consider introducing Flood drainage rights (FDR), a sustainable flood control measure, into non-engineering measures as a complement to engineering measures for flood control. FDR represent the right of regions to discharge regional floodwaters caused by extreme rainfall into the river, and are the primary means of controlling the amount of floodwaters from regions when regional flood capacity is exceeded. However, existing studies on quantitative FDR allocation still have limitations, and some previous methods have resulted in allocation schemes that are not entirely reasonable and fair because they do not comprehensively consider the influencing factors of FDR or the allocation method is unreasonable. This paper explores the impact of flooding on rural and agricultural areas. We incorporate the factors of agricultural economy and security and construct a system of the allocation indicators of FDR composed of five principles: Natural Environmental Endowment, General Economic and Social Development, Agricultural Economy and Security, Macro policy regulation, and Respect for Historical Background. Second, considering the influence of expert judgment and data of different time nodes on the allocation of FDR, we introduce the concepts of expert weight and time weight into the allocation model of FDR, and construct a new set of framework for the allocation of FDR, i.e., "[(expert weight + subjective weight)+(time weight + objective weight)]+decision making model ". To reduce the loss of information during the transformation of subjective judgments, we also introduced triangular fuzzy numbers for the transformation between expert judgments and numbers. Finally, we take the five provinces in the middle and lower reaches of the Yellow River as an example. Using the data from 2010 to 2021, we obtain the final allocation scheme (proportion) of FDR as Henan (33.26%) > Shaanxi (23.08%) > Inner Mongolia (21.31%) > Shanxi (14.44%) > Shandong (7.91%). On this basis, this paper utilizes sensitivity analysis and comparative validation to demonstrate the rationality and effectiveness of the method, and identifies several indicators that have a greater impact on the results of the allocation of FDR. FDR can form part of a set of integrated flood management system together with flood control projects, which greatly alleviates the drainage conflicts arising from flooding caused by extreme precipitation. Under extreme rainfall conditions, FDR improves drainage efficiency and minimizes the overall damage caused by flooding in the watershed. This study can contribute to the sustainable development of the watershed and provide a reference for the promotion and utilization of sustainable flood control measures.

Multi-uncertainty river health assessment in the Loess Plateau based on a novel comprehensive similarity cloud model

With the development of related research on river health assessment, the traditional assessment methods cannot solve the uncertainty problems caused by diversified indicators and ambiguous weights. In order to comprehensively understand the river health status in the Loess Plateau and solve the uncertainty of assessment results, this study takes Wuding River as the research object, and constructs an assessment indicator system incorporating the ecological environment and social functions of the river. The genetic algorithm-BP neural network was used to establish a weight learning mechanism for assessment indicators, and the system weight was calculated by combining various weighting preferences. Based on the cloud model theory, a sample data cloud and a health level cloud were constructed, and a comprehensive similarity model considering the shape and distance of the cloud diagram was developed to identify the health level of Wuding River. The spatial and temporal variability of the river health status and the sources of pressure causing unhealthy problems were analyzed. It is shown that Wuding River is in basic health status, which gradually decreases from the upstream reaches to the downstream reaches. The health status of social service functions is better than that of the ecological environment attributes such as water resources and water quality. The sources of health pressure in the upstream and downstream reaches are different. In the upstream reaches, the pressure mainly comes from natural attributes such as successive declines in water production, slow governance of water and soil erosion, and the poor stability of the river. The health pressure in the midstream and dowmstream reaches comes from the interference of human economic activities, which include deterioration of water quality caused by the discharge of fossil energy industry, destruction of aquatic habitats, and flood safety hazards caused by insufficient standards for flood control project design. In addition, SDSCM provides river managers with accurate and comprehensive health risk information to help them manage rivers more effectively.

Developing Rainfall Intensity- Frequency- Duration Curves for Three Selected Sites in the Kurdistan Region, Iraq

Developing Rainfall Intensity- Frequency- Duration Curves for Three Selected Sites in the Kurdistan Region, Iraq

Spatio-temporal water height prediction for dam break flows using deep learning

Spatio-temporal prediction of the water height for dam break flow is of great significance in flood control projects. In this article, we propose a novel deep learning model named AE-LSTM-ATT that combines AutoEncoder (AE) and Long Short-Term Memory with Attention (LSTM-ATT) to predict the dynamic behavior of the dam-break water height field in spatial and temporal dimensions. The prediction performance of the AE-LSTM-ATT model was demonstrated using dam-break flow cases with different initial heights of the water column. The AE first compresses high-dimensional inputs into low-dimensional latent space using its encoder to enable a fast computation process. Then, the latent space is adopted as an input for the LSTM-ATT to predict low-dimensional representations at future time instances that can be restored to the water height field by the decoder of the AE. The major findings of this article include three parts: (1) AE-LSTM-ATT model can successfully achieve the spatio-temporal prediction of the water height for dam break flows with high precision; (2) The proposed AE presents much better performance than those of the widely used Principal Component Analysis (PCA) and Kernel Principal Component Analysis (KPCA) in the dimension reduction; (3) The developed LSTM-ATT performs far better than the commonly used Recurrent Neural Network (RNN) and Long Short-Term Memory (LSTM) in the time-series prediction. These promising results suggest that the proposed AE-LSTM-ATT model can play an essential role in capturing and advancing the spatio-temporal features of dam-break water height, which can be applied in the field of real-time decision making for dam-break floods.

Assessment of the Perennial Floods Affecting Residential Areas Along River Tille, Katsina Metropolitan, Katsina State, Nigeria

Flooding constitutes a significant environmental challenge across Nigeria, recurring annually and notably affecting residential zones situated adjacent to streams, rivers, and Fadama areas. This study evaluates the perennial floods impacting residential locales along River Tille in Katsina Metropolitan, Katsina State, Nigeria. The research methodology encompassed field visits to the river-adjacent residential areas over a three-year span (2020-2022) and the dissemination of semi-structured questionnaires to ten respondents from six residential areas along the river. Findings indicate that the floods, attributed to factors such as heavy rainfall, proximal housing construction, the infilling of Maliyau pond, and inappropriate waste disposal, recur yearly. These floods have led to the loss of lives, property damage, and structural collapses. While local community initiatives have sought to mitigate these impacts, success has been limited. In response, the State Government, in collaboration with the World Bank in August 2020, initiated a flood control project, which commenced in September 2020 and concluded in 2021. Observations in 2022 revealed substantial flood management improvements, although certain project aspects remain unaddressed by the contractors. Further actions are recommended to ensure the project's full efficacy in managing the perennial floods and minimizing adverse effects on the community. This research is significant, offering detailed insights into the persistent flood issues in metropolitan river areas and assessing a government-executed flood control initiative.

Flood Modeling in a Composite System Consisting of River Channels, Flood Storage Areas, Floodplain Areas, Polder Areas, and Flood-Control-Protected Areas

The Linhuaigang flood control project (LFCP), situated on the Huaihe River, China, uses the river channels upstream of the LFCP, together with the hinterland areas outside the channels, to retain and store fluvial floodwaters that exceed the downstream channel’s discharge capacity. The hinterland areas are split into seven flood storage areas, three floodplain areas, eight polder areas, and three flood-control-protected areas, and they are connected to the river in various ways. A coupled hydrodynamic model was established to simulate the hydrodynamic and water volume exchange between the river channels and the hinterland areas. The flood storage area, under the control of a flood diversion sluice, was simulated with a 2D hydrodynamic model, and the inflow process initiated by the flood diversion sluice was simulated as a control structure. The polder area was generalized as a reservoir that would be filled in several hours once put into use because of its small size. The uncontrolled inflow process between the flood-control-protected areas and the channel was simulated by means of a dam break model, which could simulate levee breaching. The flooding within the flood-control-protected area, which represents a vast space, was simulated with a 2D hydrodynamic model. The floodplain area was laterally connected to the river channel along the river levee. The difference between the simulated and the measured flood peak water stage did not exceed 0.2 m in 2003 and 2007, indicating that the accuracy of the model was relatively high. In the scenario of a design flood with a return period of 100 years, the flood storage areas and the LFCP were used in the following order: Mengwa, Qiujiahu, Nanrunduan, Shouxihu, Jiangtanghu, Chengxihu, Chengdonghu, and the LFCP. When the Huaihe River encounters a flood with a return period of 1000 years that exceeds the design standard, the highest water stage upstream of the LFCP and Zhengyangguan shall not exceed 29.30 m and 27.96 m after the use of all the flood storage areas, floodplain areas, and flood-control-protected areas. The results of this research can provide technical support for the flood risk management of the LFCP.

An Analysis of Stream Flow and Flood Frequency: A Case Study from Downstream of Kelani River Basin, Sri Lanka

River floods in Sri Lanka are mainly associated with extreme rainfall events. The Kelani and Kalu rivers are recorded the highest flood frequencies and the accompanying flood damages among the river basins in wet zone (UNDP, 2011). Therefore, the specific objective of the study is to estimate the temporal probability of occurrence of flood events in downstream of Kelani river basin. Secondary data were used for the study. Daily discharges data were obtained from Hanwella gauging station for the period of 1990 to 2019 from the Department of Irrigation, Sri Lanka. Trend analysis, normal distribution and flood frequency analysis have been used. The results of the study revealed that there was a bi-modal pattern of discharges that occurred in June and October. The results also indicated that ten return periods were covered the total period of 30 years, and there was a 97 per cent probability of flood occurrence almost annually and 64 per cent probability of occurring once every two years. This study, therefore, was recommended to design flood control structures for mitigating flood risk; and to determine the economic value of flood control projects and the effect of encroachments on flood plain. Keywords: floods, frequency, downstream, return period, probability

Deep learning-based chatbot by natural language processing for supportive risk management in river dredging projects

Dredging projects play a vital role in water conservation, especially for flood control, but they often encounter natural and human-induced risks. This study addresses these challenges by creating a comprehensive knowledge base for dredging risks. This knowledge base serves several essential functions: it aids in immediate and thorough risk prevention, provides practical risk management recommendations, and assists dredging personnel in making informed decisions when dealing with risks. Furthermore, the study introduces an advanced deep-learning model that enhances access to critical information. Users can quickly find relevant risk prevention strategies by inputting keywords. The model's distinctive feature is its ability to analyze unforeseen risks through natural language processing, predict the potential impact and frequency of unexpected events, and propose appropriate risk response measures. This empowers dredging personnel to conduct preliminary risk assessments confidently. The deep learning model seamlessly integrates into LINE's communication platform, creating a river dredging project risk knowledge chatbot. This user-friendly chatbot is accessible to personnel at all project stages, enabling real-time interaction. It offers a practical way to develop and implement risk prevention plans and response measures. In summary, this research presents an innovative approach that enhances the efficiency and safety of dredging projects. By merging a knowledge base with cutting-edge technology and real-time communication, it equips dredging personnel to manage known and unforeseen risks proficiently, ultimately contributing to the success of water conservancy and flood control projects.

The Town Creek locale of Jackson, Mississippi, USA: Charles Lyell (1797–1875), exemplary fossils and a subsurface volcano

Abstract The Town Creek locale in Jackson, Mississippi exposes fossiliferous strata through stream erosion and provides evidence for stratal doming atop an extinct volcano. Charles Lyell (1797–1875) investigated the locale on his second visit to North America (1845–46) and concluded that Town Creek fossils were older than Vicksburg fossils, and that strata dipped westward from Jackson. In the 1850s, Mississippi's state geologist Eugene Hilgard (1833–1916) recognized the first volcanic doming evidence and correctly concluded that a ‘local upheaval’ had elevated the Jackson area. Subsequent research revealed an extinct volcano as Jackson Dome's source, explaining the strata dip and Lyell's observation that Jackson's Eocene fossils were older than Vicksburg fossils, later identified as Oligocene. The Jackson fossiliferous strata, known today as the Moodys Branch Formation, exquisitely preserves fossils that have contributed to numerous scientific investigations. The Town Creek locale was threatened in 2003 when a proposed flood control project would have inundated it. Scientists rallied for the preservation of the geologically and historically important Town Creek, and today it remains as a geoheritage site available to scientists and the public, with a state historical marker noting its geological importance. Long-term preservation of the locale is needed but not guaranteed.

Spatial diversion and coordination of flood water for an urban flood control project in Suzhou, China

Suzhou City, located in the Yangtze River Delta in China, is prone to flooding due to a complex combination of natural factors, including its monsoon climate, low elevation, and tidally influenced position, as well as intensive human activities. The Large Encirclement Flood Control Project (LEFCP) was launched to cope with serious floods in the urban area. This project changed the spatiotemporal pattern of flood processes and caused spatial diversion of floods from the urban area to the outskirts of the city. Therefore, this study developed a distributed flood simulation model in order to understand this transition of flood processes. The results revealed that the LEFCP effectively protected the urban areas from floods, but the present scheduling schemes resulted in the spatial diversion of floods to the outskirts of the city. With rainstorm frequencies of 10.0% to 0.5%, the water level differences between two representative water level stations (Miduqiao (MDQ) and Fengqiao (FQ)) located inside and outside the LEFCP area, ranged from 0.75 m to 0.24 m and from 1.80 m to 1.58 m, respectively. In addition, the flood safety margin at MDQ and the duration with the water level exceeding the warning water level at FQ ranged from 0.95 m to 0.43 m and from 4 h to 22 h, respectively. Rational scheduling schemes for the hydraulic facilities of the LEFCP in extreme precipitation cases were developed according to flood simulations under seven scheduling scenarios. This helps to regulate the spatial flood diversion caused by the LEFCP during extreme precipitation.

Research and Application of the Calculation Method of River Roughness Coefficient with Vegetation

The roughness coefficient is a comprehensive parameter reflecting river resistance, which is widely used in the planning and design of river regulation and flood control projects. In recent years, as the upstream water conservancy and hydro-power projects have been put into operation, the frequency of low flow in the middle and lower reaches has increased, and the frequency of flood flow has decreased. All kinds of vegetation in the river floodplain grow luxuriantly, which causes a change in the river resistance and roughness coefficient. The present study was carried out with theoretical analysis and laboratory tests. A formula for the roughness coefficient calculation was derived based on the momentum equilibrium equation and momentum exchange between the vegetation layer and upper layer. The relationship between the depth-averaged velocity within the vegetation layer and depth-averaged velocity of the whole flow was analyzed. The reliability of the formula was verified by a large amount of previous experimental data. Based on the derived formula, the variation law of the roughness coefficient with vegetation density, vegetation height, and water depth were obtained. For the emerged vegetation flow, the Manning coefficient tended to increase with the increase in the vegetation density and water depth. For the submerged vegetation flow, the Manning coefficient showed a trend of decreasing with the increase in the water depth and increased with the increase in the vegetation height. Finally, the derived formula was applied in the Yueyang reach of the Yangtze River and the Duliujian River. The study can be applied in the fields of water level-flow discharge relationship analysis and the water surface line calculation of vegetated rivers.

Frequency Analysis of Hydrological Data for Urban Floods—Review of Traditional Methods and Recent Developments, Especially an Introduction of Japanese Proper Methods

Frequency analysis has long been an important theme of hydrology research. Although meteorological techniques (physical approaches) such as radar nowcasting, remote sensing, and forecasting heavy rainfall events using meteorological simulation models are quite effective for urban disaster prevention, statistical and stochastic theories that include frequency analysis, which are usually used in flood control plans, are also valuable for flood control plans for disaster prevention. Master plans for flood control projects in urban areas often use the concept of T-year hydrological values with a T-year return period. A flood control target is a “landside area that is safe against heavy rainfall or floods with a return period of T years”. This review emphasizes discussions of parameter estimation of stochastic models and selection of optimal statistical models, which include evaluation of goodness-of-fit techniques of statistical models. Based on those results, the authors criticize Japanese standard procedures recommended by the central government. Consistency between parameter estimation and evaluation of goodness-of-fit is necessary. From this perspective, we recommend using the maximum likelihood method and AIC, both of which are related to Kullback–Leibler divergence. If one prefers using SLSC, we recommend not SLSC itself but SLSC’s non-exceedance probability. One important purpose of this review is the introduction of well-used Japanese methods. Because some techniques that are slightly different from the international standard have been used for many years in Japan, we introduce those in the review article.

Study on the Division of the Affected Zone under Construction Unloading and Its Construction Sequence of the Multiline Parallel River-Crossing Pipe Jacking

There are many advantages of reasonably determining the affected zone and its construction sequence for the multiline parallel pipe-jacking construction, such as convenient to reasonably arrange the pipeline section distribution mode, reducing the construction safety risk, and construction difficulty. Combined with the engineering construction practice of the multiline parallel pipe-jacking project for the north city drainage and flood control project through Chu River in Hefei, the strength reduction method has been utilized to study the surrounding stratum FOS for the pipe-jacking construction unloading under different overburden thickness Hs, different clear distance D, and different river water depth H w in this paper. The formula of the minimum critical overburden thickness Hsmin and the minimum critical clear distance Dmin of the surrounding stratum self-stability during pipe-jacking construction unloading have been derived. The division method of the affected zone for the multiline parallel river-crossing pipe-jacking construction which behaves as the mutual influence nonself-stability zone, the mutual influence self-stability zone, and the no mutual influence self-stability zone has been proposed. For further discussion, the construction sequence of the multiline parallel river-crossing pipe jacking has been studied.

Study on the applicability of sponge city concept to flood resilient in Sri Lankan cities: Boralesgamuwa and Sub Urban Areas

In the last few decades, climate change and urbanization have made natural disasters worse all over the world. This has increased the likelihood of flash flood disasters. The purpose of this research is to determine if the six key processes (retention, detention, infiltration, purification, storage, and drainage system) of the China sponge city concept have been accounted for in the projects carried out to construct flood-resilient towns in Sri Lanka, as well as the influence of flood mitigation. This research has identified projects that have adapted the concept's main processes by reviewing the report of the Weras Ganga Development Plan, conducting key informant interviews, and a field survey. As a result, flood height is reduced in Boralesgamuwa and sub-urban areas. But some stages are missed because the SCC is not applied as a concept to flash flood control projects in Sri Lanka.

Flood Incidences as Public Health Challenge in Katsina State, Northern Nigeria

Flood incidences are one of the major environmental hazards that occur yearly in different parts of the world. The year 2022 has witnessed series of catastrophic floods not experienced in recent times in parts of countries such as Afghanistan, Bangladesh, Italy, Pakistan, Niger Republic, Pakistan, South Africa and United State of America. Nigeria like other developing countries in the continent of Africa has also experienced this kind of floods incidences. This paper examines flood incidences as a public health challenge in Katsina state northern Nigeria. Data for the study was generated from a semi-structured questionnaire administered on 100 students. The students are those studying National Diploma in Environmental Health Technology at Hassan Usman Katsina Polytechnic, Katsina, Katsina State. Data on annual flood incidences from 2018 – 2022 was collected from the Katsina State Emergency Management Agency (SEMA) including discussions with the Directors of Information and Search and Rescue. The results have shown that flood incidences within the period under study have become a public health challenge resulting to loss of lives, injuries to victims, destruction of houses and creation of displaced persons among others. These are happening despite the efforts of Katsina State Government to tackle the challenges posed by the floods to public health. It is therefore recommended that on-going flood control projects should continue and more efforts on safeguarding public health from flood incidences be pursued.

Factors That Influence the Livelihood Resilience of Flood Control Project Resettlers: Evidence from the Lower Yellow River, China

Land requisition and resettlement of migrants are two major parts of flood control projects. After a large land area was allocated for flood control projects, livelihood resilience of resettlers became a great challenge. In this paper, Puyang County, Taiqian County, and Fan County, Henan Province, China, are chosen for a household survey. An index system to assess farming households’ livelihood resilience is constructed. After that, regression analysis and variance analysis are adopted to examine influencing factors of resettlers’ livelihood resilience. Results suggest the following: (1) Livelihood resilience of resettled farming households is on the whole lower than that of non-resettled farming households; (2) Response to policies, family scale, livelihood strategy, and skill training are major influencing factors of resettled farming households’ livelihood resilience; (3) Compared with other types of farming households, livelihood resilience of farming households with land expropriated is significantly different. In order to enhance resettlers’ livelihood resilience, the government should expand the application scope of follow-up support policies of reservoir resettlement, enhance capability construction of resettlement management departments, strengthen support for resettlers’ employment, combine resettlement with rural revitalization strategy, and improve the social security system for flood control project resettlers.

Problems and Solutions for the Flood Control Program in Medan City and its Surroundings

Medan City is currently experiencing flooding and this indicates all existing flood control projects implemented over the years have been unsuccessful. Therefore, the main objective of this research is to determine the best solution to overcome floods in the city through a literature study supplemented by a perception survey. The steps implemented include discovering the causes of the flood, determining the failure of the past flood control projects, disclosing the perception of the people affected by floods toward the city government’s commitment, and formulating the best solution to overcome the flood. It was discovered that there are two kinds of floods in Medan city which include the flash/river and the local/residence floods. The flash type was caused by the deforestation in the upstream area of the rivers flowing through the city while the local type is associated with high rainfall, lack of pervious area, and poor urban stormwater management. Moreover, the existing flood mitigation projects were observed to be unsuccessful because they applied the old paradigm with a normalization approach without compensating for the increase in the runoff discharge. This means there is a need to establish naturalization in the upper region of all rivers flowing through the city to reduce river flooding. The maintenance of the existing urban drainage system also needs to be combined with sustainable programs such as storing, absorbing, and reusing strategies to mitigate residence flooding. Furthermore, ten recommendations were proposed to stakeholders to overcome or significantly reduce flooding in Medan City and its surroundings. The first is the alignment of paradigms among stakeholders toward flood management while the last is completing related regulations and law enforcement.