Drainage Water Research Articles

Physical Properties of Soils in Selected Subdivisions in Tacloban City and Palo, Leyte

The study was conducted to analyzed and to determine the physical properties of soil such as texture, bulk density, water holding capacity, soil moisture content, pH, and organic matter content in selected subdivisions in Tacloban City and Palo, Leyte. Analysis of pH, texture, water holding capacity, and organic matter was at the Soil Research Testing and Plant Analysis Laboratory (SRTPAL) Department of Agronomy and Soil Science (DASS) VSU Baybay, Leyte. While the bulk density, soil moisture content was computed using the standard formula. To analyzed the result Analysis of Variance (ANOVA) using the SPSS Program to determine whether soils from subdivisions categorized as waterlogged and mountainous, developed and developing subdivisions derived from their filling and parent materials were significant different. The results showed that soils from various categories from subdivisions had no significant effect on bulk density, water holding capacity, & soil moisture content. However, some properties such as soil pH were significant in the waterlogged and mountainous area. It is recommended that a further study be conducted to include all appropriate soil parameters and procedures such as liming for acid soils, cause of erosion, flooding, water drainage capacity, depth to water table and other significant soil quality parameters. Also recommend for in-depth study by the developers and engineers to ensure that the soil quality be suitable for housing and for the safety of the homeowners.

Performance of water quality simulation model for lifting drainage water joints and mixing zone determination

Limited water resources with gradual increase in water demand led to higher dependence on drainage water as one of the non-conventional water resources in Egypt. However, there was no precise approach for using such resource. The practices ranged between stopping lifting drainage water to main canals at many locations due to the water quality degradation in the drains and pure dependence on polluted drainage water by farmers. This implies the importance of applying the mathematical models that provide precise and flexible alternative for the dependence on the drainage water. This procedure could save the big investments that were used in the lifting stations while mitigating the environmental hazards. Cornell Mixing Zone Expert System (CORMIX) model is one of these mathematical simulation models. The study used surface discharge sub-model (CORMIX3) to define the mixing zone between the lifted drainage water from Mehalet Rough drain and the freshwater in Mit Yazid canal, by investigated biochemical oxygen demand (BOD) and total dissolved solids (TDS). The simulation results verified that the two investigated parameters met WQ standards for the Egyptian law 48/1982. BOD standard value was met after 448.36 m, in 723 s. TDS standard value was met after 4.46 m, in 7.8 s. This was far ahead of the first municipal station regardless low quality of these parameters in the drain. This is the first time to apply this model in the irrigation sector in Egypt, and the results were promising for defining the precise approach to reuse the drainage water in Egypt.

A fully coupled multiscale phase-change model at the porous interface for transpiration cooling: coupling dynamics pore-scale networks to continuum-scale free flow

Being a promising method for thermal protection system, transpiration cooling has received wide interest recently. Numerical simulation for transpiration cooling, however, has been limited due to the mis-matching between the pore-scale two-phase flow and external high-temperature aerothermodynamic environment, which induced by conventional decoupled or iterative one-way coupled simplification methods. In this work, a fully coupled continuum-scale and pore-scale model is established for transient transpiration cooling at the interface between boundary layer flow and porous medium through coupling Computational Fluid Dynamics (CFD) and Pore-Network Model (PNM), termed as the multiscale CFD-PNM coupled method. The coupled method allows to capture detailed displacement and phase change of two-phase flow at pore-scale, revealing the strong interaction of the water vapor with the external free flow within a high temperature boundary layer. After successfully validating the new coupled model by comparing with the Two-Phase Mixture Model (TPMM) solution, a number of cases mimicking the cooling at the interface of typical blunt bodies are simulated. The results show that the multiscale CFD-PNM coupled method can not only provide the thermal protection effect prediction, but also reveal many critical features that beyond the reach of continuum-scale studies. Some pore-scale phenomena that are important to the overall transpiration cooling effects are revealed, including transient phase change and composition variation of water vapor, imbibition and drainage of two-phase flow related to pore-scale capillary thresholds and applied boundary pressures, as well as the two-way mass transfer at the interface, such as the invasion of external hot air.

Simulating Agricultural Water Recycling Using the APEX Model

Irrigation plays a vital role in many agricultural crop production regions. Drainage water recycling (DWR) is a popular irrigation water management system that collects excess water drained from cropland fields and stores it in on-site reservoirs for reuse. The efficacy of these systems varies by location, climate, irrigation frequency, and crop demands. Simulating this system would be beneficial for assessing the impact of water and land management practices on agriculture and natural resources. This study presents the development of computational algorithms for DWR simulation with the Agricultural Policy Environmental eXtender (APEX) model, along with the results for 39 testing sites where both reservoir and drainage systems are adopted. Simulating a DWR system with the revised reservoir module, the APEX model simulates irrigation water reuse ranging between 29% and 93%; sediment reduction of around 66%; nitrogen loss reduction of 23% and 73% for the mineral and organic forms, respectively; and phosphorus loss reduction of 22% and 79% for the soluble and sediment-transported forms, respectively. In conclusion, the results provided by the APEX model for sediment loss reduction align with field data, but discrepancies for nitrogen and phosphorus losses emerged from this test.

Long-term changes in soil biological activity and other properties of raised beds in Longan orchards

Introduction The Longan fruit tree of the Vietnam Mekong Delta is grown in raised beds to improve water drainage during the rainy season and can live as long as 100 years. Objective This research explores the extent to which the soil microorganisms as well as soil physical and chemical properties of these raised beds degrade over a period of 60 years under traditional management practices. Materials and Methods Raised bed topsoil samples at depths of 0–20 cm were obtained from four different Longan orchards raised bed age groups: group 1) 15–25 years (L1–L5); group 2) 26–37 years (L6–L10); group 3) 38–45 years (L11–L15); and group 4) 46–60 years. Soil biological properties were tested for nitrogen-fixing bacteria, phosphorus solubilizing bacteria, potassium solubilizing bacteria, calcium solubilizing bacteria and silicate solubilizing bacteria, β-glucosidase, urease, phosphomonoesterase, and phytase. Soil samples were also tested for moisture content, soil texture, soil porosity, and bulk density as well as soil chemical properties including pH, electrical conductivity (EC), soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (NH4+, NO3−), available phosphorus (AP), exchangeable potassium (K+), exchangeable calcium (Ca2 +), available silicate (SiO2), available copper (Cu), zinc (Zn), boron (B) and manganese (Mn). Key findings: The results showed that soil moisture, soil porosity, sand content, SOM, TP, TK, available P, exchangeable Ca2 +, available Si, nitrogen fixing bacteria number, β-glucosidase, urease, phosphomonoesterase, and phytase gradually and significantly decreased in the raised bed soil as the Longan orchard increased in age. Pearson correlation analysis between the ages of Longan orchards and soil properties revealed that raised bed ages were positively correlated with soil bulk density, but negatively correlated with soil moisture content, soil porosity, SOM, TN, β-glucosidase, urease, phosphomonoesterase, and phytase. Principal component analysis (PCA) showed Longan yields had a positive correlation with available NO3− but negative correlation with NFB, exchangeable Ca2 +, pH, and available B. These findings reveal that traditional long-term management of Longan trees in raised beds significantly reduce soil organic matter, moisture content, porosity, and soil fertility with impacts on soil microbial numbers and activity within raised bed soils. Future Directions This suggests that more sustainable management practices, such as mulch and cover crops that decrease soil compaction and increase soil organic matter, improve soil porosity, total N, and feed soil microorganisms that are critical to nutrient cycling are needed to improve raised bed soil quality.

Removal of Inorganic Pollutants and Recovery of Nutrients from Wastewater Using Electrocoagulation: A Review

Water pollution is a major concern due to its detrimental effects on the environment and public health. The particular danger of inorganic pollutants arises from their persistent toxicity and inability to biodegrade. Recently, electrocoagulation (EC) has been demonstrated as an alternative sustainable approach to purifying wastewater due to the increasingly strict pollution prevention rules. In particular, EC has been used to remove inorganic pollutants, such as Cr, Zn, Pb, or As. EC has emerged as a sustainable tool for resource recovery of some inorganic pollutants such as N and P that, when recovered, have value as plant nutrients and are critical in a circular economy. These recovered materials can be obtained from diverse agricultural drainage water and recycled as fertilizers. In this work, a state-of-the-art technique is reviewed describing the advances in contaminant removal and nutrient recovery using EC through an in-depth discussion of the factors influencing the contaminant removal process, including operating pH, time, power, and concentration. Furthermore, limitations of the EC technology are reviewed, including the high-power consumption, fast deterioration of the sacrificial electrodes, and the types of contaminants that could not be efficiently removed. Finally, new emerging constructs in EC process optimization parameters are presented.

Prediction of Sediment Transport and Deposition in the Stone Buddha Temple Reservoir Based on HD and ST Bidirectional Coupling Model

Reservoirs deliver vital ecological services, including water storage and drainage. However, these functions are increasingly compromised by the dual pressures of climate change and human activities. Among the most pressing concerns is reservoir sedimentation, highlighting the urgency of investigating hydrodynamic sediment scouring. This study focuses on the plain reservoirs of Liaoning Province, using the Shifo Temple Reservoir as a case study. An optimized sediment scouring scheme was developed based on the reservoir’s hydrodynamic characteristics to improve water and sediment management. A coupled hydrodynamic and sediment transport (ST) model was constructed to simulate runoff dynamics and sediment distribution within the Liao he River Basin, while the MIKE21 model was applied to simulate the interaction between the hydrodynamics and sediment transport. The study analyzed groundwater dynamics across different runoff scenarios, seasons, and representative years, offering a scientific foundation for optimizing water and sediment allocation strategies. The results demonstrated a strong correlation between simulated and observed data during validation, confirming the accuracy of the hydrodynamic simulations. Utilizing the coupled HD and ST modules, the study proposed a sediment transfer scheme. The analysis revealed that flow rates between 165 and 190 m3/s significantly enhance sediment scouring in the long term (2029–2039) compared to the short term (2024–2029), effectively reducing sedimentation, minimizing deposition length, and lowering silt removal costs. The findings offer critical insights for predicting reservoir evolution and conducting risk assessments, thereby contributing to the sustainable management and ecological restoration of water systems in Liaoning Province.

KARAKTERISTIK TANAH SULFAT MASAM DAN PENGELOLAANNYA UNTUK LAHAN PERTANIAN

Acid sulfate soils are quite abundant in Indonesia, and some have been used for agricultural land. The main problem with this soil is the presence of pyrite compounds (FeS2). The oxidation of these compounds causes the soil to become acidic, metals and bases dissolve so that the soil becomes poor and the life of aquatic biota affected by the drainage water is disturbed. The oxidized soil, if flooded again, causes an increase in ferrous iron ions and hydrogen sulfide which can poison plants, therefore management of acid sulfate soils needs to be carried out so that the soil has characteristics that can support plant growth. Some soil management actions that can be taken are controlling the activity of microorganisms in the oxidation and reduction processes of pyrite, providing amelioration materials and fertilization, land management and water management.

Application of coniferous bark as sorbent material for per- and polyfluoroalkyl substances – A case study in Sweden

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic contaminants commonly found in drainage water from waste management facilities. Within the European Union, these facilities either treat the water locally or transfer it to wastewater treatment plants to reduce harmful emissions. However, PFAS are a broad class of compounds with varying physicochemical properties, leading to different removal efficiencies for adsorbents. Activated carbon and ion exchange resins are effective but costly, and they can become saturated with other contaminants. Therefore, this study aims to explore inexpensive, abundant alternatives for reducing PFAS concentrations in the environment. In Sweden, bark is a by-product of forestry activities, primarily used as fuel in heat and power plants. This study evaluates the ability of pine and spruce bark to remove PFAS from contaminated drainage water. Initial laboratory experiments employed liquid-to-solid ratios of 10 and 20 to assess the performance of both materials. Results indicated that pine bark exhibited better removal efficiencies, particularly when a layered column with pine bark followed by spruce bark was utilized. The overall removal efficiencies for short-chain PFAS (perfluorinated carbons: PFCA C3–C6 and PFSA C4–C5) and long-chain PFAS (PFCA > C7 and PFSA > C6) were below 20%, except for perfluorooctane sulfonic acid (PFOS), which showed reductions of 40%–80%. The pH of the treated water decreased from 7 to 4 (pine bark) and 5 (spruce bark) after treatment. In a larger-scale trial, a combination of 50% pine bark and 50% spruce bark was tested, achieving similar reductions for PFOS. Although the removal efficiencies were insufficient for exclusive treatment, these materials may be useful in specific applications targeting long-chain PFAS or in conjunction with other treatment methods.

Demonstration scale treatment of drainage canal water in the Nile Delta through a combination of facultative lagoons and hybrid constructed wetlands

Drainage canal water (DCW), a mixture of Nile water, drainage water and municipal wastewater, is largely used for irrigation in the Nile Delta. Facultative lagoons (FL) and constructed wetlands (CWs) represent interesting options for DCW treatment before its agricultural re-use, but very few studies investigated their implementation in Egypt. This work aimed at developing at demonstration scale (250 m3 d-1) a FL+CW treatment train capable to turn DCW into an effluent reusable in agriculture. Three types of hybrid CWs were tested in parallel for 530 days. The combination of FL with a cascade hybrid CW, operated at a 200 L d-1 m-2 surface loading rate, led to medium-to-high removal efficiencies (suspended solids 90%, total nitrogen 84%, phosphate 80%, COD 67%, faecal coliforms 2.2 Log) and surface removal rates (COD 47.5 t y-1 ha-1, total nitrogen 10.9 t y-1 ha-1, faecal coliforms 1.5 1011 MPN y-1 ha-1). The effluent, compliant with class C of EU 2020/741 regulation, is potentially reusable to irrigate numerous Egyptian crops. The results show that the combination of FLs with cascade hybrid CWs has a great potential for the treatment of DCW and low-strength municipal wastewater, with near-zero energy consumption, null consumption of chemicals and a land requirement varying between 1.1% and 1.5% of the agricultural land irrigated with the treated DCW.

Effect of nozzle clogging on vortexing during continuous casting processes: results of an experimental simulation

ABSTRACT Exogenous oxide inclusions in continuously cast steel primarily arise from the entrapment of slag during various stages of steelmaking, including in furnaces, ladles, and molds. To maintain steel cleanliness, operators often pause ladle and tundish processes before ‘slag vortexing’ begins, since this phenomenon (slag vortexing) can adversely affect product quality. Previous studies indicate that sub-entry nozzle clogging can lead to productivity issues and quality defects in cast products. Clogging can cause non-uniform reductions in nozzle diameter along the molten metal flow direction. This study examines the impact of drain port taper (a representation of nozzle clogging) on air core vortex formation during water drainage (simulating molten metal) using a parameter, ‘Characteristic Volume of Air Core.’ Results show that clogged drain ports are prone to vigorous vortexing, significantly affecting efflux velocity and static pressure at drain outlets. The current study also analyzes the dynamic behavior of air core vortexing due to nozzle clogging, revealing that clogging can induce fluctuations in liquid discharge, adversely affecting the casting process. These findings have practical implications for continuous casting processes in steel and other metals.

Choosing an efficient mass exchange apparatus for desorption of hydrogen sulphide from reservoir and drainage waters

Industrial wastewater is often contaminated with hydrogen sulfide and sulfides. This poses significant risks to both the environment and human health and life as H2S is extremely toxic. Therefore, water purification from it is vital, and the choice of an effective desorber device is an urgent issue. This paper investigates the process of H2S desorption from wastewater in mass exchange devices with a continuous bubbling bed (DCBB), a column with falling plates (CFP), and a horizontal device with bucket-like dispersers (HDBD). To analyze the kinetic and technological characteristics of the process, the following indicators were selected: the product of the mass exchange coefficient on the contact surface of phases (K·F), reduced to 1 m3 of the volume of the apparatus, and the degree of hydrogen sulfide desorption. The most complete desorption of hydrogen sulfide occurs at pH≤5. For practical needs, it is suggested to acidify the water to pH=5.5...6.0. It was established that the partial pressure of H2S increases linearly with increasing temperature, and an increase in salinity from 2...4 to 130...160 kg/m3 leads to its increase by 1.45...1.5 times. The best desorption indicators can be achieved in HDBD at pH=4.97. The efficiency of cleaning in CFP and DCBB is significantly affected by the specific air flow rate. The highest values (K·F) per 1 m3 that were achieved in desorbers are, mol/(s·Pa·m3): HDBD – 1.94·10-5, in CFP – 5.55·10-6, DCBB – 6.9·10-6. The ratio of the product (K·F) in HDBD to CFP is 3.5, and in HDBD to DCBB 2.8. It was possible to achieve the maximum degree of desorption of 37.8 % in DCBB; in CFP, this indicator is 74.1 %, and in HDBD – 77.7 %. Experimental studies have generally confirmed the effectiveness of using HDBD, and the results obtained under production conditions on real drainage and reservoir waters could find be practically implemented in hydrogen sulfide utilization technologies

Seasonal Variations in Ochreous Precipitates and Drainage Waters in the Grantcharitsa Tungsten Deposit, Western Rhodopes, Bulgaria

Seasonal variations of drainage waters and ochreous products of their discharge from the closed abandoned old gallery at the Grantcharitsa scheelite deposit (Bulgaria) were studied by field and laboratory methods for the period 2019–2023. The drainage is generated under anoxic conditions and is inherently diluted (EC = 100–202 µS/cm) with S (6–12 mg/L), Si (6–22 mg/L), Na (6–10 mg/L), Fe (0.2–3.3 mg/L), and W (0.19–3.5 µg/L), at a pH 4.4–6.5 and temperature 7–11.5 °C, with dissolved oxygen DO (2.1–7.7 mg/L). The concentrations of Fe and W and the pH of the water are variable and reach their maximum values during the dry (autumn) season. It was found that such parameters as pH, Eh, DO, Fe and W content change dramatically at a distance of up to 3 m from the water outlet; the values of pH, DO and Eh are sharply increased with a simultaneous nearly 5–6-times reduction in iron and tungsten content. The decrease in the contents of these elements is associated with the precipitation of ochreous material consisting of nanoscale ferrihydrite with an intermediate structural ordering between 2-line and 6-line ferrihydrite (major phase), hematite, goethite, quartz, montmorillonite and magnetite. The formation of ferrihydrite occurs as a result of abiotic and biotic processes with the participation of iron-oxidizing bacteria. Besides Fe2O3 (55.5–64.0 wt.%), the ochreous sediment contains SiO2 (12.0–16.4 wt.%), SO3 (1.3–2.4 wt.%), Al2O3 (3.1–6.8 wt.%) and WO3 (0.07–0.11 wt.%). It has been shown that drainage waters and ochreous sediments do not inherently have a negative impact on the environment. The environmental problem arises with intense snowmelt and heavy rainfall, as a result of which the accumulated sediments are washed away and carried in the form of suspensions into the water systems. It is suggested that by providing atmospheric oxygen access to the closed gallery (via local boreholes), it is possible to stop the generation of iron-enriched drainage.

Karakteristik Pertumbuhan Mucuna (Mucuna bracteata L.) dengan Metode Sungkup dan Tidak Disungkup di Kabupaten Serdang Bedagai

Covering of Mucuna bracteate L. cuttings plays an important role in the survival rate of Mucuna Bracteata plants, as it helps maintain optimal humidity and temperature levels. The adjustment process after the cover is opened is very important before moving the cuttings to open land. This study aims to measure the impact of covering on the survival rate of cuttings. This study used a Randomized Block Design (RAK). The treatments used were Covered (P1) and Uncovered (P2), by applying Topsoil 3kg (K0), Topsoil 1.5kg + Sand 1.5kg (K1), Topsoil 1.5kg + Black Soil 1.5kg (K2), Topsoil 1.5kg + Cow Manure 1.5kg (K3). This research was conducted from August 10 to September 9, 2024. This research was conducted in the Yard of a House in Ngaraja 1 Village, Dolok Merawan District, Serdang Bedagai Regency. Based on the Least Significant Difference (LSD) Test, Covering and Topsoil (P1K0) consistently showed the best results in terms of number of shoots, tendril length, number of leaves and Root Length. This indicates that covering and topsoil provide optimal conditions for the early growth of Mucuna plants. Topsoil and sand (P1K1) showed the highest root volume. This suggests that the addition of sand to the topsoil may have increased aeration and water drainage, thus encouraging root development. Keywords: covering, vegetative growth, Mucuna bracteata L.

Monitoring and Modelling Fluxes of Water and Nutrients to Surface Drainage Network From Irrigated Agricultural Fields in a Hydraulically Reclaimed Coastal Area

ABSTRACTThis paper describes the application of a physically based agrohydrological model (named FLOWS), coupled with a kinematic wave approach model (named KWV) for water and solute runoff routing, for interpreting the fate of water and nutrients coming from cultivated fields to surface drainage network located in ‘Piana del Sassu’ in the Arborea plain, a hydraulically reclaimed area with shallow groundwater. Modelling was supported by a large complex database on soil, groundwater and surface drainage water, which was used for establishing the boundary conditions for simulations, as well as for calibrating and validating the model. The model FLOWS provided the water and nutrient fluxes to the surface water, which were passed to the KWV model for their routing along the elementary fields in the experimental area and from these to the ditches and finally to the drainage channel. The modelling approach effectively predicted the water and solute distribution along the soil profile, as well as the losses of water and nutrients to the surface water. The results showed a significant amount of water and dissolved nutrients to flow quickly from the soil uppermost layer to the surface drainage network during both the irrigation season and during rainfall events. During irrigation applications, losses were mostly due to rainfall intensity exceeding the maximum infiltration velocity of the shallow soil layer in the case of sprinkler irrigation and to subsurface lateral drainage in the case of exceeding irrigation water provided by drip irrigation. This makes the Sassu plain a significant contributor of nutrients (nitrate and phosphorus) to the surface water. Consequently, even though the agricultural activities might not be an important issue for the groundwater vulnerability, the management of water and nutrients should be significantly improved to avoid ecohydrological threats to the important coastal water bodies present in the area.

The LTAR Croplands Common Experiment at Upper Mississippi River Basin-Ames.

Agricultural systems evolve from the interactions of climate, crops, soils, management practices (e.g., tillage, cover crops, nutrient management), and economic risks and rewards. Alternatives to the corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] (C-S) cropping systems that dominate in the US Midwest may provide more sustainable use of resources, reduce the documented environmental impacts of current C-S systems, and improve production efficiency and ecosystem services. Innovative management practices are needed to offer producers options to increase farm resilience to variable weather conditions and offset negative environmental impacts. In response to this need, the Upper Mississippi River Basin Long-Term Agroecosystem Research network site at Ames, IA, established a cropland experiment in 2016 to investigate an alternative crop management system that includes reduced tillage, cover crops, and right source, right rate, right time, and right place (4R) nitrogen (N) management. The experimental site is located on the Iowa State University Kelley Research Farm in Boone County, IA. Crop, soil, air, and tile drainage water measurements are made throughout the year using published methods for each agronomic and environmental metric. Our goal is to provide quantitative information to farmers, consultants, agribusiness partners, and state and federal agencies to help guide decisions on the effective use of alternative management practices. Future changes in experimental treatments will adopt a knowledge co-production approach whereby researchers and stakeholders will work collaboratively to identify problems, implement research protocols, and interpret results.

Mitigating flood risk at Shah Alam, Malaysia for sustainable development

The natural environment and infrastructure are severely damaged by floods, which are becoming frequent occurrences. It may not be able to stop floods given the impending climate change and variability of the weather. Yet mapping flood risk can help with both mitigation and prevention of flooding. The Shah Alam experiences flash floods yearly, which is why it was chosen. An interactive approach to decision-making under multi-criteria decision analysis (MCDA), the analytical hierarchy process (AHP), is used. The flood risk zone is divided into five categories very low-risk (32.38%), low-risk (22.25%), moderate-risk (23.17%), high-risk (18.87%), and very high-risk (3.33%) respectively. Based on the data gathered for this study, the economic losses are identified, low-risk areas (RM 2091), moderate-risk areas (RM 2343), and high-risk areas (RM 2728). The historical flood events occur in the Seksyen 36, 18, 17, and most of the southern part of Shah Alam, Malaysia. Rainfall and the Klang River have the biggest effects on these regions, with water drainage systems being critical in the Shah Alam area to reduce the risk of floods. When analysing flood risks in the Shah Alam region and throughout the nation, important stakeholders both state and non-state actors can benefit greatly from the flood susceptibility map provided by this study.

Development of Grooves in Gas Diffusion Layers for PEM Fuel Cells Considering Mechanisms of Oxygen Transport and Water Drainage

Development of Grooves in Gas Diffusion Layers for PEM Fuel Cells Considering Mechanisms of Oxygen Transport and Water Drainage

Navigating the definition of urban flooding: a conceptual and systematic review of the literature

ABSTRACT Urban flooding is a significant global challenge, posing risks to urban planners, policymakers, and communities. This paper reviews the literature to analyze how urban flooding is defined across scientific disciplines. Our objectives are to uncover the elements used to define urban flooding and evaluate how these elements can impact future research and practice. A key difficulty is the lack of a consistent, comprehensive definition that captures both physical and social dimensions of urban flooding. Current definitions often focus solely on physical aspects (e.g., rainfall, infrastructure) or social impacts, rarely integrating both. This fragmentation hinders effective flood risk management and interdisciplinary collaboration. Our contribution is a multifaceted definition incorporating spatial and social concerns, including water origins, built environment characteristics, and local community aspects. We introduce the "Urban Water Transect" concept to illustrate the continuum of flood risk across urban zones, addressing a gap in the literature. The analysis reveals that many papers discuss flooding causes without providing an explicit definition. Urban flooding is predominantly defined based on water source, imperviousness, and drainage infrastructure. Future research should adopt an interdisciplinary perspective considering both physical and social aspects, potentially transforming urban flood risk management.

The effect of leaf leachates addition on denitrification in subsurface flow constructed wetlands is shaped by the bed substrate type

In constructed wetlands (CWs), bed substrate and leaf leachates from vegetation may correct the low C/N ratio that constrains heterotrophic denitrification and nitrate removal from irrigated agricultural drainage water. However, the interactive effects of bed substrate type and leaf leachates on denitrification are still unknown. By focusing on a CWs pilot plant, we designed a laboratory experiment to evaluate i) wether denitrification potential rates varied among bed substrates: calcareous gravel (a conventional substrate), gravel+soil from a natural wetland (silty loam Solonchak, 1.5 % of organic C) and gravel+biochar from pyrolyzed ornamental plants (75 % of organic C); and ii) the response of denitrification within each bed substrate to the addition of their respective leaf leachates. We found that denitrification potential rates were lower in gravel beds (0.011 ± 0.006 μgN2O-N gDM−1 h−1) than those observed with the addition of biochar (0.06 ± 0.03) and especially soil (0.78 ± 0.04), with soil being the most advantageous option. Besides, leaf leachates addition boosted denitrification rates in all cases. Nevertheless, the effect of leachates was relatively higher in gravel beds than in the other substrates (15 times higher vs. 2 and 4 times with soil and biochar, respectively). Our outcomes highlight limited denitrification when using gravel substrate not only by low C but also due to essential macro- and micro-elements, and support the role of plant leaves as internal and self-sustainable source of nutrients.