Drainage Facilities Research Articles

A method based on elitist genetic algorithm for calibrating the thermo-physical surface indicators: Its principles, validation and application to bioswales

Pavement is closely linked to the hydrological characteristics of the surface, which affects the infiltration and retention of surface runoff, leading to changes in thermo-physical surface indicators such as surface albedo, surface emissivity, volumetric heat capacity, thermal diffusivity, average soil temperature and surface humidity. Green drainage facilities, particularly bioswales, can mitigate runoff and improve microclimates by altering the flow path of water and thermo-physical surface indicators. While the thermo-physical indicators of artificial pavement surfaces such as sand, asphalt, cement, brick and stone have been studied and applied, those of bioswales have yet to be thoroughly investigated, and there is a dearth of scientific evaluation methods for their thermal effect. In this study, a genetic algorithm-based method for calibrating thermo-physical surface indicators was established, and its reliability was validated by comparing the thermo-physical indicators of asphalt pavement surfaces with existing literature. Two bioswales covering 200 m2 were designed and constructed, and their surface air temperature (1.5-meter from the surface) was monitored under irrigating and non-irrigated scenarios, and the thermo-physical indicators of two bioswales surface were determined. The temperature of bioswales in relevant literature was calculated by using the calibration results, and compared with the measured air temperature. The calibration method exhibited an error range of −9.6% to + 4.3%, and the surface temperature error resulting from the application of calibration parameters was 0.9133 to 0.9338. By establishing a method for determining the thermo-physical indicators of surface pavement and obtaining the thermo-physical indicators of bioswale surfaces using the surface temperature data, this study provides essential support for evaluating the thermal environment effect of bioswales.

DESIGNING OF OPEN CHANNELS AND CLOSED CHANNELS FOR DRAINAGE FACILITIES IN AIRSIDE

Drainage facilities are one part of the airside facilities that are important to ensure the safety of the airside area when weather changes occur. This study aims to make drainage that can be carried out to ensure the safety of the airside area from stagnant water. The calculation of airside drainage refers to the planned drainage calculation rules so that the drainage channels can design accordingly so as not to interfere with the operation of other facilities. In the design of drainage work, the material requirements for making open and closed channels at Dewadaru Karimun Jawa Airport must be precisely designed so that the work takes place by the specified planning and quality standards. The research uses a mixed methodology that the exploratory study by conducting a literature study that compares observation. The analysis starts by finding the volume for each work item based on Standar Nasional Indonesia (SNI) 2052-2017, a national iron and concrete standard. The result shows the excavation of soil for making channels, the total volume required is 880.24 m3, the importance of sand is 40.76 m3, the book of substantial rebates of a mixture ratio of 1: 2: 3 is 23.82 m3, and the book of K300 Concrete works for U-Ditch type C channels (100 x 100) is 116.29 m3. For the needs of the required iron volume of 16,415.09 kg, formwork of 1,408.45 m2, stone river masonry size 100 x 100 by 139 m3, stone river masonry size 50x50 amounted to 42.05 m3, and the volume of plastering work of the channel amounted to 192.46 m2. The conclusion of this study is the accuracy of design required to calculate each work item's volume.

Analysis of urban drainage system to avoid rain water overflow on the access road to Juanda Airport

The access road to Juanda Airport from Jalan Raya Waru (Aloha Resto) Sidoarjo is frequently flooded when it rains with a height of more than 30 cm along 1.6 km. This greatly annoys the flow of traffic to the airport. The airport can only be passed through this street and the Juanda Airport toll road. This research was conducted by observing and recording conditions during the occurrence of floods and analyzing the drainage facilities in the research area based on the 5-years design discharge because this location is a densely populated residential and industrial area. The results showed that the addition of channel capacity using U-ditch was not able to accommodate the 5-year planned discharge of approximately 2.670 m3/sec. Since around the industrial location, there is a natural water reservoir that can keep water up to 3.526 m3/sec, it is necessary to add a water pump to drain water to the temporary water reservoir location so that water does not stagnate on the access road to Juanda Airport.

The Causes and Countermeasures of Soil Erosion of Karst Landform in Guizhou Province

Nowadays, soil erosion has become the focus of social attention. Due to topography, climate, precipitation, human activities, and other factors, this phenomenon is particularly serious in the Karst landform region. Therefore, this paper takes the classic Karst landform region of Guizhou as an example, dividing the karst landform into two different types, namely, the surface karst landform and the underground karst landform, with different positions as variables. Based on the previous data, systematic analysis of the causes of karst, and factors that promote soil erosion and water runoff in corresponding regions. Looking into the future, the issue of soil erosion in the kalandforms still needs to be changed. For the countermeasures, drainage facilities can optimize runoff, and forestry technology could affect vegetation. However for the long run method for generation after generation, people's awareness should be fundamentally raised. Thus, the most economical way to deal with this is to increase the government and relative department limitations.

Soil salinity management practices in coastal area of Bangladesh: a review

Soil salinity is a significant threat to agriculture and livelihood, particularly in the Southern coastal areas of Bangladesh. Soil salinity is extended from 0.833 to 1.056 million hectares (about), with an increase of 26% between 1973 and 2009. Out of about 1.689 million hectares of coastal land, about 1.056 million hectares are affected by soil salinity of various degrees covering 49 Upazila (sub-district) of 19 districts. About 0.328, 0.274, 0.189, 0.161, and 0.101 million hectares of land are affected by very slight (S1), slight (S2), moderate (S3), strong (S4), and very strong salinity (S5), respectively. Data recorded by SRDI manifests new ingression of salinity in Narail (18.71 ha), Jashore (14.99 ha), Barishal (13.96 ha), Gopalgonj (6.27 ha), Jhalakati (4.69 ha), and Madaripur (0.72 ha) districts. Soil salinity also encroached a large area of Bhola (53.84 ha), Patuakhali (40.08 ha), Khulna (27.92 ha), and Bagerhat (23.14 ha), besides minor ingression in other districts. The salinity level is almost double (2.8-18.5 to 4.0-42.8 dS/m) from 1973 to 2009 in Sharankhola Upazila of Bagerhat district, Dumuria Upazila of Khulna district and Shyamnagar Upazila of Satkhira district (SRDI, 2010). Different causes are involved in increasing the water and soil salinity of the coastal area of Bangladesh, like withdrawal of fresh river water from upstream, irregular rainfall, faulty management of sluice gates and polders, regular tidal water flooding in an unprotected area, the capillary rise of soluble salts, decreased surface water availability, lowered ground water table, reduced soil moisture content, the introduction of unplanned shrimp cultivation, lack of drainage facilities. Some of the widespread soil and land management techniques adopted in the saline areas of Bangladesh to cope with the salinity are polder (123), farm-pond (khamar-pokor), sarjan procedure, usage of raised shrimp farm bund for year-round cropping, mulching (keeping land covered in winter and summer months), land leveling, pitcher (kolosh) irrigation to grow watermelon, dibbling method, the addition of organic matter, chemical fertilizers and cultivation of saline tolerant crop varieties, particularly rice. Vol. 10, No. 1, April 2023: 1-7

Effectiveness of Controlled Tile Drainage in Reducing Outflow and Nitrogen at the Scale of the Drainage System

The impact of controlled drainage (CD) on the groundwater table (GWT), drainage outflow, surface runoff, and nitrogen reduction at the drainage system scale in the Wielkopolska region was analyzed in this study. Based on field research, mainly by monitoring of GWT changes in 2019–2020, the DRAINMOD model was calibrated and validated. Hydrological soil water balance simulations were carried out with 36 and 9 combinations for CD and free drainage (FD), respectively. The modelling period was March-September for 10 different dry, wet, and normal years from the period of 1961 to 2020. The next step was to use the results of drainage outflow modelling and chemical constituent analyses of drainage water samples to determine NO3-N concentrations and calculate NO3-N pollution loads. As a result of the simulations, the importance of the timing of the start of the outflow retention in the adopted model variants was determined, indicating the earliest assumed date of 1 March. The appropriate CD start date as well as the initial GWT has a significant impact on the effectiveness of CD application in reducing the volume of drainage outflow and reducing the amount of NO3-N entering open water with it. The application of CD under the conditions of the analyzed drainage facility makes it possible to retain up to 22 kg of NO3-N per hectare.

Об обеспечении безопасной эксплуатации главной водоотливной установки рудника «Удачный»

Safety of the underground mining operations largely depends on the reliability of the functioning of the drainage facilities system. Practice shows that over the past few years, the reliability of the main drainage system of the underground kimberlite mine Udachny was noticeably decreased. One of the reasons for this was the low operational reliability of pumping equipment. External examinations of the failed parts of the flow part of pumps operating in the drainage systems of domestic kimberlite mines indicate the dominance of hydroabrasive wear in the overall picture of their multifactorial destruction. Mine waters pumped from the drainage mine workings of the Udachny mine is considered the most polluted among the mines of ALROSA. The main reason for the increase in the concentration of solid particles in the mine waters pumped to the daytime surface by the pumping equipment of the main drainage plant of the Udachny mine was the growing pollution of the waters coming from the drainage basins of the district drainage into its clarifying reservoirs. Such an intensive removal of mechanical impurities from the catchments of the district drainage into the clarifying tanks of the main drainage system is explained by an increase in the rate of siltation of the catchment tanks. And the rapid siltation of the catchments, in turn, is caused by the systematic removal of sludge-slurry pulp from the lower part of the skip trunk. It is established that the sludge slurry is formed during the overload of the extracted kimberlite ore from the feeder to the conveyor belt. There, its spilled part is washed off with water used for irrigation of diamond-bearing raw materials into the skip barrel. To reduce the rate of siltation of the drainage basins of the district drainage system, a mechanized complex for cleaning spilled rock mass was developed, described in the article.

Spatial and Temporal Rainfall Analysis of the Bidi Tobacco Growing Areas of India.

The monsoon extremities, such as heavy rainfall, drought, and cyclones are becoming frequent across India and causing substantial damage to commercial crops. To predict/identify the trend in rainfall of Bidi tobacco growing areas were studied for variability, trend, and detection of any change in monthly rainfall over the years (1990-2020) using Mann-Kendall trend analysis and Sen’s slope tests. Monthly rainfall in three unique Bidi production zones has shown distinct trends. A positive trend was observed in March, April, August, September, November, and December while negative trends were in June and July months in Gujarat. During the crop growth period, the trend is positive except in October, the magnitude of change was negligible. However, supplemental irrigation is to be planned during water deficit periods of the nursery (June and July) and critical crop growth periods. In Karnataka, a positive trend from February to October was observed while a negative trend during November, December, and January. The magnitude was high in January (+) and September (-) and significant. The period of negative trend has coincided with the harvesting hence, the crop may not get affected. However, high rainfall during the crop growth period causes a detrimental effect. To mitigate the inundation proper drainage facility should be created through field channels to flush out excess water to avoid saturation at the root zone as this crop is especially extremely sensitive to poor aeration and anaerobic conditions. A positive trend was observed in January, February, March, June, August, and September months in Andhra Pradesh, whereas a negative trend was high in October & November which coincided with crop growth and might significantly affect Bidi tobacco. The positive trend in rainfall during June is high and the same can be utilized for nursery during July-August through proper moisture conservation measures.

Socialization and Evaluation of the BLM Program for Penataban Giri Banyuwangi Village

A good and healthy environment is very important in supporting human survival. Settlement drainage is a facility or infrastructure in settlements to drain rainwater from one place to another. The wastewater distribution system is a series of water structures that function to reduce or dispose of wastewater from an area or land, both households and industrial areas. The KOTAKU Program (City Without Slums) BLM Program for Penataban Giri Banyuwangi Village has been completed, namely the construction of drainage facilities, toilets, and beautification. The hope is that after the construction of some of these facilities can help the level of cleanliness and quality of a healthy environment for the community. Hopefully in the future the community can maintain the local wisdom values ​​of environmental preservation in the Penataban Village, namely the value of environmental adaptation, the value of responsibility, the value of environmental awareness, and the value of cooperation. The values ​​of local wisdom as an effort to maintain the environment in Penataban Village are reflected in the activities of residents in maintaining drainage channels for waste water management, maintaining environmental cleanliness and the spirit of community cooperation to beautify and preserve the surrounding.

Prague Water Net Zero Strategy 2025: methodology and roadmap

Abstract In 2019, Prague set out its Prague 2030 Climate Plan and Pražské vodovody a kanalizace, a.s., as the operator of drinking water supply and drainage facility in Prague and Pražská vodohospodářská společnost, a.s., responsible for infrastructure management (collectively known as Prague Water) are a natural part of the mitigation and adaptation activities. Both companies committed to reaching a net zero operational CO2 footprint in 2035. The carbon footprint of the company will be certified according to the ČSN ISO 14064-1 standard. The paper presents a roadmap of the early stage of the project, the calculation of the CO2 footprint and the ISO certification process together with planned mitigation activities. The main goal of the contribution is to share know-how about the application of carbon-wise management principles in a large utility company. This makes the paper useful for worldwide utilities at a similar stage of carbon footprint measurement and reduction.

Inflow Prediction of Centralized Reservoir for the Operation of Pump Station in Urban Drainage Systems Using Improved Multilayer Perceptron Using Existing Optimizers Combined with Metaheuristic Optimization Algorithms

Owing to the recent increase in abnormal climate, various structural measures including structural and non-structural approaches have been proposed for the prevention of potential water disasters. As a non-structural measure, fast and safe drainage is an essential preemptive operation of a drainage facility, including a centralized reservoir (CRs). To achieve such a preemptive operation, it is necessary to predict the inflow of the drainage facilities. Among the drainage facilities, CRs are located downstream of the drainage area, and their pump stations are operated according to the CR water level. The water level of a CR depends on the inflow, as does the preemptive operation of its pump station. In this study, as a nonstructural measure, the inflow prediction for the CR operation in an urban drainage system was proposed. For predicting the inflow of a CR, a new multilayer perceptron (MLP) using existing optimizers combined with a self-adaptive metaheuristic optimization algorithm, such as an improved harmony search, was proposed. Compared with the adaptive moment, which yields the best results among other existing optimizers, an MLP using an existing optimizer combined with an improved harmony search improves the mean square error and mean absolute error by 0.1767 and 0.0349, respectively.

Detection and quantitative evaluation of pumping distress on bridge deck pavement through field and laboratory experiments

Pumping distress refers to the phenomenon of dynamic water entering a pavement, soaking the cement concrete layer to form slurry, and being pumped out of the pavement void under the action of traffic loading. Pumping distress is frequently reported in high temperature and rainy regions, such as Sichuan province in China. Various factors contribute to pumping distress on bridge decks, but most of these factors have merely been subjected to qualitative assessment. The aim of the study is to conduct a comprehensive quantitative analysis through three years of field investigations and laboratory experiments. The field investigations include ground penetrating radar (GPR), pavement permeability tests, skid resistance tests, and drainage facilities surveys. The quantitative analysis of the field and laboratory inspections revealed that the formation reason, deterioration rate, and damage degree of pumping distress were different between the truck and emergency lanes. The occurrence of pumping distresses was significantly related to the uneven construction of the bridge deck leveling layer, compaction segregation, and poor drainage. Additionally, the influence of pavement thickness uniformity on pumping distress was evaluated by incorporating GPR techniques. Failure in the waterproof adhesion layer resulted in the barrier between the cement concrete deck and the asphalt mixture breaking, which allowed alkaline sources to move and transfer to the pavement layer easily. The outcomes of this study can help bridge authorities and construction contractors choose appropriate design and construction measures to prevent pumping distress.

Analysis of the Influencing Factors of Crystalline Blockages in Mountain Tunnel Drainage Systems Based on Decision Analysis Methods

Crystalline blockages in mountain tunnel drainage systems are becoming a common environmental problem. Considering the lack of research on the influence degree of the factors affecting crystalline blockages in mountain tunnel drainage systems, this paper classified and evaluated the importance of relevant factors through decision analysis methods. Our purpose is to provide a comprehensive understanding of the primary factors causing crystalline blockages in tunnels. The influence factors are selected and categorized through a literature review, and then the influence factors are screened twice by the expert scoring method and the gray-whitening weighted function clustering method to eliminate the less important influence factors. Finally, the influence factors are evaluated systematically according to the hierarchical analysis method. The results indicate that the factors affecting the crystalline blockage of the drainage system can be divided into five categories: hydrology, geology, shotcrete materials, drainage facilities, and the cave environment. Among these factors, shotcrete materials are the key factors affecting the problem of crystalline blockages. Specifically, the density of shotcrete and the content of calcium in cement have a significant impact on the crystalline blockages, which have the following comprehensive weights: 0.221 and 0.152, respectively. Since the shotcrete materials are human controllable factors, they can be taken as the key research objects to solve the problem of crystalline blockages.

Bioactive Molecules Derived from Plants in Managing Dengue Vector Aedes aegypti (Linn.).

Mosquitoes are the potential vectors of several viral diseases such as filariasis, malaria, dengue, yellow fever, Zika fever and encephalitis in humans as well as other species. Dengue, the most common mosquito-borne disease in humans caused by the dengue virus is transmitted by the vector Ae. aegypti. Fever, chills, nausea and neurological disorders are the frequent symptoms of Zika and dengue. Thanks to various anthropogenic activities such as deforestation, industrialized farming and poor drainage facilities there has been a significant rise in mosquitoes and vector-borne diseases. Control measures such as the destruction of mosquito breeding places, a reduction in global warming, as well as the use of natural and chemical repellents, mainly DEET, picaridin, temephos and IR-3535 have proven to be effective in many instances. Although potent, these chemicals cause swelling, rashes, and eye irritation in adults and children, and are also toxic to the skin and nervous system. Due to their shorter protection period and harmful nature towards non-target organisms, the use of chemical repellents is greatly reduced, and more research and development is taking place in the field of plant-derived repellents, which are found to be selective, biodegradable and harmless to non-target species. Many tribal and rural communities across the world have been using plant-based extracts since ancient times for various traditional and medical purposes, and to ward off mosquitoes and various other insects. In this regard, new species of plants are being identified through ethnobotanical surveys and tested for their repellency against Ae. aegypti. This review aims to provide insight into many such plant extracts, essential oils and their metabolites, which have been tested for their mosquitocidal activity against different life cycle forms of Ae. Aegypti, as well as for their efficacy in controlling mosquitoes.

Enhancing the resilience of ecosystem services under extreme events in socio-hydrological systems: A spatio-temporal analysis

Due to the adverse impacts of severe droughts on various aspects of human life and ecosystem services (ESs), the spatio-temporal assessment of the resilience of ESs under droughts is essential. In this paper, we propose a new methodology for assessing ESs-based resilience, taking into account the seven resilience principles: a) redundancy and diversity, b) managing connectivity, c) managing slow variables and their feedback, d) complex adaptive system (CAS) thinking, e) experimentation and learning, f) broadening participation, and g) polycentric governance. These principles enable us to consider the main social, political, hydrological, economic, and environmental aspects concerning resilience which have been overlooked in previous studies. The methodology is evaluated by applying it to Zarrinehroud River Basin (ZRB) in north-western Iran. A set of qualitative and quantitative criteria and their sub-criteria are proposed for quantifying the ES-based resilience and generating time series of resilience against severe droughts in several sub-basins in the study area. To evaluate the criteria and sub-criteria, the required data are derived from calibrated SWAT and MODSIM models as well as experts’ judjments. The time series of ES-based resilience under 128 Water and Environmental Resources Management (WERM) scenarios (for enhancing agricultural practices, altering and modernizing irrigation methods, improving irrigation network and drainage facilities) and Climate Change (CC) scenarios (RCP 4.5, RCP6.0, and RCP 8.5) are derived for each sub-basin based on short-term (2020–2049) and long-term (2020–2098) periods. The low resilience values (0.53–0.6) of all sub-basins under the base management scenario (the status quo scenario (SC0)) illustrate the need for implementing some projects to enhance the ESs in the study area. The results show that the WERM scenario SC12346 can improve the values of the resilience criterion in sub-basins up to 0.85 and reduce the vulnerability of the study area to droughts. By evaluating all management scenarios, scenario SC12346 is reported as the best scenario, since it can significantly increase the resilience of all sub-basins against extreme droughts with an acceptable cost of 636 million US dollars compared to other scenarios. Under this WERM scenario, the resilience values of sub-basins increase up to 40%. This scenario suggests implementing a set of projects such as improving irrigation networks and drainage facilities.

A preliminary investigation of water storage in check‐dams across China's Loess Plateau using electrical resistivity tomography

AbstractCheck dams are typical deposition sites that trap and store eroded sediments from uplands and are widely constructed on China's Loess Plateau (LP) as an effective soil and water conservation practice. Compared with slope land (SL), check‐dam land (DL) may store more water resources and play an important role in food production and water regulation in watersheds. However, little is known about the water distribution characteristics and driving factors of DL. In this study, we investigated seven DLs in different regions of the LP and four SLs under different land uses using the non‐invasive electrical resistivity tomography (ERT) technique and established a nonlinear model correlating electrical resistivity (ρ) and soil water content (θv). The results showed that θv can be successfully estimated by ρ using the power function model according to the coefficient of determination (R2 = 0.77) and root‐mean‐square error (RMSE = 0.035 cm3/cm3), indicating that ERT is applicable for estimating water resources in the loessal region. Generally, the distribution of DL water resources can be divided into three types: (i) unsaturated throughout the entire profile, (ii) unsaturated in the top but saturated in the lower profile and (iii) approximately saturated throughout the profile with minimal spatial variation. The different water distribution characteristics among the DLs may be related to the soil texture, land use type and drainage facility. The total mean water storage in the 0–4 m profile of DL for different land‐use types was 1.5–2.0 times higher than that of SL. Therefore, DL water stores should not be ignored when assessing hydrological cycles and the water budget in a watershed in the LP. Future research should be implemented to understand the hydrological processes and ecological effects of both DL and SL to optimize water management strategies with sustainable ecosystem functions in the loessal region.

Urban waterlogging mitigation based on the concept of sponge city

In recent years, many cities around the world have experienced severe urban waterlogging disasters due to decreasing rainfall infiltration caused by land cover changes with rapid urbanization, and increased frequency of heavy rainfall events, including localized torrential rain. Traditional drainage systems and internal control concepts have failed to meet the requirements of urban safety. To address the challenging problem of urban waterlogging, China proposed the Sponge City in 2014. From the perspective of natural climate and urban construction planning, this paper makes an analysis of the causes of urban waterlogging, points out the limitations of traditional drainage facilities, and discusses the many hazards associated with urban waterlogging. This paper explains the meaning of Sponge City and the basic ideas of Sponge City construction. Based on the discussion of Sponge City development, this paper analyzes the Sponge City construction in Xixian New Area, and explains the significance of Sponge City to solve the problem of urban waterlogging. Through this idea, I would like to explore the common issues in countries suffering from heavy rainfall disasters such as Japan and Malaysia. The study hopes to provide a deeper thinking on ways to use nature to solve the waterlogging.

222Radon reduction in small-scale water supply systems using low-technology reduction methods in the Republic of Korea: A field research and mass balance model approach

In rural areas, low-technology radon reduction methods are essential for safe access to clean groundwater. This study monitored the radon reduction rates in small-scale groundwater-based water supply systems in the Republic of Korea and also presented a mass balance equation using physical environmental conditions from three radon reduction methods. The mass balance results showed that the radon reduction rate would be affected by the groundwater flow rate (m3/day), capacity of the drainage facility (m3), surface area of air-water interface (m2), air-water ratio (dimensionless), and ventilation system. The radon reduction order was as follows: simultaneously powered and non-powered aeration method (free-fall (60.0 %) > aeration (19.6 %) > decay (0.9 %) > diffusion (0.2 %)), low-technology non-powered aeration (free-fall (60.0 %) > decay (3.4 %) > diffusion (0.9 %)), and only storage (free-fall (35.5 %) > decay (4.4 %) > diffusion (1.1 %)). Overall, non-powered aeration using the maximum free-fall effect has the potential for use as a low-technology reduction method and natural decay during water storage is the most important factor underlying seasonal variations in the reduction effect.

Change of stream network connectivity under polder‐type flood control measure

AbstractPolder is usually used for flood control in the river delta area. With the rapid development of urbanization, the dikes or pumps cut the original stream network system, and the stream network connectivity (SNC) and the river system pattern have changed. The dikes or pumps generally force up the river's water level, and regional flood formation mechanisms and processes have changed. In order to quantitatively describe the characteristics of polder‐type flood control measure (PFCM) and the change law of SNC, firstly, the streams inside polders were generalized as virtual streams, a hydrological‐hydrodynamic model was constructed by connecting Hydrologic Engineering Center‐Hydrologic Modeling System and MIKE11 model. Secondly, an SNC evaluation model was constructed based on flow resistance and hydrological process. Finally, the SNC under different scenarios was simulated and evaluated to reveal the influence of the PFCM on SNC. And the dominance analysis method obtained the main control factors of SNC changes. The results showed that the pumps as the main drainage facility under the PFCM, SNC after the opening of the pumps were increased by 0.060, 0.103, and 0.311 for 50%, 30%, and 3% frequency flood scales compared with the pumps closed, respectively. However, compared with the natural stream (without the PFCM), the SNC decreased by 0.391, 0.456, and 0.487, respectively, at the same time of the same flood scale. The PFCM negatively impacted the SNC, and the number of pumps was the main control factor of the SNC.

The quantitative assessment of impact of pumping capacity and LID on urban flood susceptibility based on machine learning

Drainage facilities such as drainage pumping systems and Low Impact Development (LID) practices are effective measures to reduce urban flood risk. The quantitative identification of their influence on the reduction of urban flood susceptibility (UFS) is of great significance in providing scientific references for urban flood control. In this study, we constructed a conceptual method to investigate the spatial variation of UFS based on the machine learning models (i.e., Convolution Neural Network (CNN) and Support Vector Machine (SVM)), which has been tested in Wuhan City of China with good performances. After model evaluation, we have quantitatively studied the impact of two flood mitigation measures (pumping stations and LID practices) on the UFS. In particular, we evaluated the UFS mitigation efficiency of several designed scenarios using different combinations of pump discharges and LID area fractions by comparing them against default scenarios. We found a nonlinear negative response relation between the reduction of UFS with either the increase in pump discharge or LID area fractions. The proportion of the area of highest susceptibility (PAH) decreases as the pumping capacity increases, and when the pumping capacity is 2.5 times the default condition, the PAH reduces to 45% from 73.7% of no pump stations and reaches its minimum value. When the LID layout area is 100% of the whole region, the PAH can reduce to 51% from 67.7% of no LID. The findings can be beneficial for the design of optimal preventative strategy to sufficiently reduces UFS.