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•The study provides a methodology with different EMPs through SWAT model at sub-basins/HRUs.•The phase-wise analysis at the sub-basins/HRUs scale clarifies the erosion ...aspects.•Implementation of EMPs combinations is limited to constraints, and suggestions to policy-makers.
Land, water, and air are the most essential resources blessed by nature to humankind, conserved and maintained with steadfast efforts. This study applies the Modified Universal Soil Loss Equation (MUSLE) to identify erosion prone sub-basins and a non-linear optimization algorithm to determine the optimal area combination of Ecological Management Practices (EMPs) control sediment yield within permissible limits at a minimum cost. The model is practiced for critical sub-basins in the Genale watershed to assess the effectiveness of five EMPs individually and as a combination in controlling sediment yields and peak flow. A relative assessment revealed that terracing as an individual (61.8%) and EMPs combinations (78.5%) are better in reducing sediment yield at the sub-basin scale. Considering the environmental and economic viewpoint, the total cost of EMPs (for five critical sub-basins), applied to reduce sediment yield, is 46.101 million USD (United States Dollar) or (1.844 billion Ethiopian birr). EMPs are environment friendly and cost-effective to reduce sediment yield.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Analyzed 1400 storm events in 153 catchments across the United Kingdom.•Improved Time-to-Peak prediction from current static methods.•Proposed dynamic prediction encompassing storm and antecedent ...moisture condition.•Narrowed from an available 43 input parameters to a new model with a only six inputs.•Developed a final model with storm-specific, static and dynamic catchment inputs.
In flood forecasting and design for peak flows, understanding and characterizing the hydrologic response to rainfall events is vitally important. One of the key parameters utilized to characterize the catchment response time is the Time-to-Peak (Tp), which represents the net rise time of a storm hydrograph, or the time from when a precipitation event begins to contribute to stream discharge, to the time that peak flow (Qp) is reached. Previously, influencing factors on Tp have been static in nature with no consideration of the variability in Tp due to size of the storm event and the antecedent moisture conditions of the watershed (seasonal effects). Using ~1400 storm event observations and the corresponding catchment characteristics of 153 stream gauges across the United Kingdom (UK), the importance of different factors on estimating Tp are evaluated. These data points span three decades, and this breadth of temporal data allowed meaningful annual trends to be observed, and seasonal variations in soil moisture to be identified and applied. A new “wetness coefficient” is applied herein, to reflect the antecedent conditions within a catchment. The Qp is selected as a dynamic variable, utilized to represent the magnitude of a given storm, due to the demonstrated correlation with Tp. An explicit equation based on gene expression programming is designed, which accounts for the dynamic nature of Tp through Qp and seasonal moisture effects. The results of the proposed model are compared to the results of the existing equation for Tp prediction in the UK, outlined by the Flood Estimation Handbook (FEH). The proposed equation (with Nash-Sutcliffe Coefficient, R2 and RMSE values equal to 0.60, 0.66 and 3.64, respectively), has improved characteristics compared with the traditional FEH equation (Nash = 0.42, R2 = 0.54, and RMSE = 4.37). A forensic analysis of the contributing factors for Tp involves development of an empirical model with improved prediction accuracy, by accounting for the dynamic inputs, improving previous models both statistically, as well as in the hydrologic understanding of the catchment response.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
RESUMO Na concepção de obras hidráulicas, como as barragens, necessita-se, para um dimensionamento seguro, de estudos referentes às vazões máximas. O estado do Ceará é caracterizado por apresentar um ...número elevado de reservatórios projetados por equações empíricas antigas. Entretanto, devido aos poucos dados existentes em algumas regiões, necessita-se transpor informações das regiões monitoradas para as não monitoradas. Este trabalho elaborou modelos de regionalização para a obtenção de vazões máximas para períodos de retorno de 1.000 e 10.000 anos em barragens localizadas no Ceará. As variáveis empregadas nas equações foram: área de drenagem da bacia, comprimento do rio principal, tempo de concentração, precipitação com duração de uma hora e diferença de cota entre o exultório e o ponto mais remoto da bacia. Utilizaram-se os dados de projeto de 30 barragens e calcularam-se as vazões máximas por meio do software HEC-HMS. Os testes estatísticos e os valores dos coeficientes de determinação (0,95) permitem considerar as equações adimensionais propostas consistentes e passíveis de serem utilizadas em análises preliminares de projetos hidráulicos.
ABSTRACT In the design of hydraulic works, such as dams, studies referring to the peak flow rates are required for safe dimensioning. The state of Ceará is characterized by having a high number of reservoirs designed by ancient empirical equations. However, due to the limited data available in some regions, it is necessary to transpose information from monitored regions to unmonitored ones. This work elaborated regionalization models to obtain peak flows for return periods of 1,000 and 10,000 years in dams located in Ceará. The variables used in the equations were: drainage area of the basin, length of the main river, concentration time, rainfall lasting 1 hour, and the difference in elevation between the basin and the most remote point of the basin. Project data from 30 dams were used and the peak flows were calculated using the HEC-HMS software. The statistical tests and the values of the determination coefficients (0.95) allow to consider the proposed dimensionless equations consistent and capable of being used in preliminary analyzes of hydraulic projects.
In this hydrological study, we developed a Transformer-based model to forecast urban river discharges and predict flood peaks, crucial for flood mitigation in urban areas prone to inundation. ...Utilizing daily precipitation data from 63 meteorological stations and flow data from hydrological stations, we established a correlation using the Random Forest method to determine the lag time between precipitation and flow. The model, enhanced with alternative loss functions – Weighted MSE Loss (WMSE), Huber Loss (Hloss), and Quantile Loss (Qloss) – instead of traditional Mean Squared Error (MSE), aims to project daily flow rates for seven days. Our findings indicate that Hloss significantly reduces absolute errors in peak value predictions, while WMSE improves linear correlation in forecasting. The accuracy remains stable for the initial four days, with a decrease from the fifth day. This approach, integrating diverse loss functions, presents a novel method for accurately predicting river discharges, offering vital insights for proactive flood management.
•Unique loss functions tailored to amplify peak flow event prediction accuracy.•Novel integration of DSW preprocessing with Transformer for hydrology forecasting.•Lag time optimization using Random Forest, enhancing input data synchronization.•Advanced seven-day flow forecasting leveraging data from 63 meteorological stations.•Dynamic model update strategy proposed for long-term hydrological shifts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The topography plays a crucial role in determining drainage effects on water flows.•Nitrogen fluxes are generally enhanced following drainage installation.•Phosphorus and PPP losses are rather ...reduced on artificially drained fields.•This trend may reverse on flat terrain where drainage may reduce on-site retention.•It needs to be considered for any risk assessment or management decisions.
Agricultural intensification has led to a large increase in drained arable land and pastures worldwide over the last two centuries. The installation of land drains not only affects the water balance of a landscape, but also influences the susceptibility to erosion, nutrient cycling, transport of plant protection products (PPPs) and greenhouse gas emissions. Due to the complex nature of environmental systems, the direction in which the substance flows are affected remains unclear, as does the strength of the effects. In this literature review, the focus is on the most relevant site-specific factors that affect the soil moisture regime, erosion, nitrogen (N) and phosphorus (P) fluxes, and PPP fluxes under undrained and drained conditions. The considered factors are the topography, soil characteristics, drainage types, rainfall characteristics and land management. Case studies from temperate climate zones represent the basis of the discussion, with a focus on continental Europe and the USA.
In most cases, drainage enhances the total annual water flows from arable fields, while the effects on peak flows were variable, with the local topography playing a crucial role. There exists a certain level of consensus in the literature that subsurface drainage methods reduce the risk of erosion, while surface drainage may increase erosion at the edge of drainage channels. Nitrogen fluxes are generally enhanced following drainage. This is especially true for organic soils with large stores of organically bound N and, therefore, a high loss potential. For P losses, the trend goes in the opposite direction, with generally reduced losses seen following drainage installation. Similar findings are expected in relation to PPP losses. However, these trends may reverse on flat terrain, where subsurface drainage may reduce the on-site retention of these compounds. Overall, the literature reveals the patterns by which drainage affects hydrology, nutrient and PPP fluxes, although it is also evident that the combination of site-specific factors is influential. This hence needs to be considered as part of any risk assessment or management decisions.
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Cough peak flow (CPF) is a useful clinical measurement to assess neuromuscular activity and effective coordination, yet it is rarely used in clinical practice outside of the management of patients ...with neuromuscular disorders. A CPF of above 160 L/min is required for an effective cough and less than 270 L/min is associated with increased secretion retention and risk of infection. Reduced CPF can be due to a number of mechanisms including reduced respiratory muscle strength, lack of co-ordination of glottic closure and opening, airway obstruction and, age and activity related changes. CPF has been shown to be correlated with other measures of pulmonary function in neuromuscular disorders and in predicting extubation failure. Patients with Parkinson's disease have a reduced CPF even at early stages and dedicated expiratory muscle strength training (EMST) has been shown to be beneficial. Sequential studies in patient with stroke-associated dysphagia reported CPF was correlated with risk of respiratory infection and results of formal swallow assessments.
Age-related changes in expiratory muscle strength and lung physiology contribute to increased risk of aspiration and pneumonia. EMST may have a role in healthy adults to improve muscle strength and effective cough, potentially reducing risk of respiratory tract infections even in the absence of disease.
CPF has potential to be extremely useful in clinical practice in a wide spectrum of diseases. In particular, studies in patients with frequent exacerbations of COPD and recurrent pneumonia are currently lacking and would be of benefit to explore the relationship between ineffective cough and recurrent infection.
•Cough peak flow (CPF) is an under-utilised tool to measure the maximum expiratory flow.•CPF has been mainly studied in patients with neuromuscular diseases (NMDs) and to predict the success of extubation.•The utility of CPF in other conditions merits further validated studies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Mechanical insufflation-exsufflation (MIE) facilitates airway clearance to mitigate respiratory infection, decompensation, and ultimately the need for intubation and placement of a tracheostomy tube. ...Despite widespread adoption as a respiratory support intervention for motor neuron disease, muscular dystrophy, spinal cord injury, and other diseases associated with ventilatory pump failure and ineffective cough peak flow, there is debate in the clinical community about how to optimize settings when MIE is implemented. This article will demonstrate the clinical utility of MIE graphics in titrating the initial MIE settings, guiding upper airway and lung protective strategies and providing insight to clinicians for ongoing clinical management.
Real-time peak flow prediction under heavy precipitation is critically important for flood emergency evacuation planning and management. In the case of emergency evacuation, every second matters as a ...slightly longer lead time could save more lives and reduce the associated social, economic, and health impacts. Here, we present a model (named SIGMA) based on the principle of signal matching to facilitate real-time peak flow prediction at sub-hourly scales (e.g., minutes to seconds). The SIGMA model divides the target watershed into small zones and the heavy precipitation falling into each zone is collected into a small water tank. As the water tank moves downstream and arrives in the watershed outlet, it will discharge the collected precipitation and generate a small single-pulse streamflow signal. By combining all small signals coming from all zones within the watershed, we will be able to generate a synthesized peak flow signal. The proposed model is applied to simulate the peak flow events observed in a real-world watershed to verify its effectiveness in real-time flood prediction. The results suggest that the presented model can reasonably predict three key aspects of a peak flow event, including the peak flow rate, the arrival time of peak flow, and the duration of the peak flow event. The proposed model is demonstrated to be effective in real-time flood prediction and can be used to support flood emergency evacuation planning and management.
•A model for real-time peak flow prediction based on signal matching (named SIGMA) is presented.•The model can predict peak flow rate and its arrival time and duration at sub-hourly scales.•The model can support flood emergency evacuation planning and management.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The present study identifies the hydraulic efficiency of a novel onsite sanitation system at variable hydraulic shock loading conditions. The system consisted of three chambers, each working as an ...up-flow anaerobic bioreactor, accommodated within a single unit. The hydraulic characteristics were identified with the help of residence time distribution (RTD) analysis by step feeding of lithium chloride (LiCl) solution into the system. The experiments were run at variable hydraulic loading conditions at different peak flow factors (PFF) of 1, 2, 4 and 6 while maintaining 24-h hydraulic retention time. As revealed in the RTD analysis, the biofilm reactor achieved a very good hydraulic efficiency that varied from 0.76 to 0.81 at PFF 1, 2 and 4. Although in the case of PFF6, it was comparatively low. It was noted that the dispersion number was always below 0.2 at variable hydraulic shock loading conditions under different PFFs, which indicated that the reactor behaved perfectly between mixed-flow and plug-flow reactor. The system was also able to achieve good pollutant removal efficiency for chemical oxygen demand (COD) and total suspended solids (TSS) under all PFFs, which was more than 68 and 75%, respectively.
► The integrated modeling system proved to be a useful approach for studying the effects of urbanization on runoff and flood. ► Smaller flood event is more affected by urbanization than larger flood. ...► Floods discharges are more affected by urbanization than annual runoff. ► At daily time step modeling, flood volume is more affected by urbanization than flood peak.
This study developed and used an integrated modeling system, coupling a distributed hydrologic and a dynamic land-use change model, to examine effects of urbanization on annual runoff and flood events of the Qinhuai River watershed in Jiangsu Province, China. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) was used to calculate runoff generation and the integrated Markov Chain and Cellular Automata model (CA-Markov model) was used to develop future land use maps. The model was calibrated and validated using observed daily streamflow data collected at the two outlets of watershed. Landsat Thematic Mapper (TM) images from 1988, 1994, 2006, Enhanced Thematic Mapper Plus (ETM+) images from 2001, 2003 and a China–Brazil Earth Resources Satellite (CBERS) image from 2009 were used to obtain historical land use maps. These imageries revealed that the watershed experienced conversion of approximately 17% non-urban area to urban area between 1988 and 2009. The urbanization scenarios for various years were developed by overlaying impervious surfaces of different land use maps to 1988 (as a reference year) map sequentially. The simulation results of HEC-HMS model for the various urbanization scenarios indicate that annual runoff, daily peak flow, and flood volume have increased to different degrees due to urban expansion during the study period (1988–2009), and will continue to increase as urban areas increase in the future. When impervious ratios change from 3% (1988) to 31% (2018), the mean annual runoff would increase slightly and the annual runoff in the dry year would increase more than that in the wet year. The daily peak discharge of eight selected floods would increase from 2.3% to 13.9%. The change trend of flood volumes is similar with that of peak discharge, but with larger percentage changes than that of daily peak flows in all scenarios. Sensitivity analysis revealed that the potential changes in peak discharge and flood volume with increasing impervious surface showed a linear relationship, and the changes of small floods were larger than those of large floods with the same impervious increase, indicating that the small floods were more sensitive than large floods to urbanization. These results suggest that integrating distributed land use change model and distributed hydrological model can be a good approach to evaluate the hydrologic impacts of urbanization, which are essential for watershed management, water resources planning, and flood management for sustainable development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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