scholarly journals Analysis of Runoff According to Application of SWMM-LID Element Technology (II): Parameter Uncertainty Analysis

2020 ◽  
Vol 20 (6) ◽  
pp. 445-450
Author(s):  
Eung Seok Kim
Keyword(s):  
Parameter Uncertainty ◽  
Low Impact Development ◽  
Low Frequency ◽  
Small Scale ◽  
Total Runoff ◽  
Uncertainty Index ◽  
Peak Runoff ◽  
Uncertainty Indices ◽  
Parameter Uncertainty Analysis ◽  
Lower Uncertainty

This study quantitatively analyzed the degree of uncertainty associated with runoff based on the sensitivity analysis of runoff parameters using Low Impact Development (LID) element technology of study (I). Uncertainty was analyzed for parameter uncertainty, uncertainty of runoff, and uncertainty about the degree of parameter and runoff. Parameter uncertainty indices showed lower uncertainty indices as a whole and uncertainty indices of peak runoff were higher than that of total runoff in runoff uncertainty. The reason for this is that the LID element technology itself is intended to store low-frequency small-scale rainfall, so that the uncertainty index of peak rainfall seems to be highly uncertain. As a result of the analysis of uncertainty degree associated with runoff, it was found that the uncertainty of storage depth of bio retention cell and rain garden was low, while the heaviness parameters of rain barrel had the highest uncertainty index. In future experiments and research, it is necessary to modify the parameter range suitable for Korea, which will be helpful for urban development, reduction of nonpoint source pollution, and designing of low frequency rainfall storage facilities.

scholarly journals Analysis of Runoff According to Application of SWMM-LID Element Technology (I): Parameter Sensitivity Analysis

2020 ◽  
Vol 20 (6) ◽  
pp. 437-444
Author(s):  
Eung Seok Kim
Keyword(s):  
Industrial Development ◽  
Low Impact Development ◽  
Low Frequency ◽  
Simulation Method ◽  
Small Scale ◽  
Storm Water Management Model ◽  
Total Runoff ◽  
Rainwater Management ◽  
And Performance ◽  
The Given

An increase in the ratio of impermeable area due to urban watersheds and industrial development has led to an increase in nonpoint source pollution and floodplains. In order to solve these problems, development and application of low impact development (LID), which is a rainwater management facility, is actively underway. In this study (I), parameters and ranges applied to the Storm Water Management Model-Low Impact Development (SWMM-LID) model are examined. To this end, 100 scenarios were created through the simulation method within the parameter range, and the sensitivity of peak and total runoff to the influence of the parameters of each element technology dealing with runoff was analyzed. As a result, bio retention cell, green roof, rain garden, rain barrell, in the given order, showed a sensitive response. However, since the LID element technology itself is intended to store low-frequency small-scale rainfall, it is important to understand the degree of rainfall, from low to high frequency. Further, the results of this study can be used as basic data for the design and development of LID element technology and performance verification of LID facilities.

scholarly journals Evaluation of Low Impact Development and Nature-Based Solutions for stormwater management: a fully distributed modelling approach

2019 ◽  
Author(s):  
Yangzi Qiu ◽  
Abdellah Ichiba ◽  
Igor Da Silva Rocha Paz ◽  
Feihu Chen ◽  
Pierre-Antoine Versini ◽  
...  
Keyword(s):  
High Resolution ◽  
Stormwater Management ◽  
Low Impact Development ◽  
Peak Discharge ◽  
Small Scale ◽  
Spatial Distributions ◽  
Land Uses ◽  
Runoff Volume ◽  
Total Runoff ◽  
Porous Pavement

Abstract. Currently, Low Impact Development (LID) and Nature-Based Solutions (NBS) are widely accepted as sustainable approaches for urban stormwater management. However, their complex impacts depend on the urban environmental context as well as the small-scale heterogeneity, which need to be assessed by using the fully distributed hydrological model and high resolution data at small scale. In this paper, a case study (Guyancourt), located in the South-West of Paris, was explored. Three sets of high resolution X-band radar data were applied to investigate the impact of variability of spatial distribution of rainfall. High resolution geographic information has been processed to identify the suitable areas that can be covered by the LID/NBS practices, porous pavement, green roof, and rain garden. These individual practices, as well as the combination of the three, were implemented as scenarios in a fully distributed and physically-based Multi-Hydro model, which takes into consideration the variability of the whole catchment at 10 m scale. The performance of LID/NBS scenarios are analysed with two indicators (total runoff volume and peak discharge reduction), with regards to the hydrological response of the original catchment (baseline scenario). Results are analysed with considering the coupling effect of the variability of spatial distributions of rainfall and land uses. The performance of rain garden scenario is better than scenario of green roof and porous pavement. The most efficient scenario is the combination of the three practices that can reduce total runoff volume up to 51 % and peak discharge up to 53 % in the whole catchment, and the maximum values of the two indictors in three sub-catchments reach to 60 % and 61 % respectively. The results give credence that Multi-Hydro is a promising model for evaluating and quantifying the spatial variability of hydrological responses of LID/NBS practices, because of considering the heterogeneity of spatial distributions of precipitation and land uses. Potentially, it can guide the decision-making process of the design of LID/NBS practices in urban planning.

scholarly journals Runoff quantity response of three urban mountain parks-hilltop subtype in humid subtropical climate based on SWMM

2019 ◽  
Vol 79 ◽  
pp. 03015
Author(s):  
Yuanyuan Li ◽  
Jialin Liu ◽  
Jianlin Zhang
Keyword(s):  
Unit Area ◽  
Low Impact Development ◽  
Small Scale ◽  
Subtropical Climate ◽  
Cover Type ◽  
Mountain Watersheds ◽  
Catchment Areas ◽  
Sustainable Stormwater Management ◽  
Peak Runoff ◽  
Precipitation Events

With the development of sustainable stormwater management, urban parks have the advantages and necessities in constructing low impact development system to reduce and reuse stormwater. This study aims to understand the hydrological processes in small scale mountain watersheds based on three typical hilltop parks in Chongqing, China. Sub-catchment areas were divided into paved square type (PST), vegetation cover type (VCT) and mixed cover type (MCT). Native stromwater models by SWMM were created under 25 mm, 50 mm, 4 years and 20 years precipitation events to simulate the runoff quantity. The runoff quantity per unit area in different sub-catchments was provided as : PST > MCT >VCT. Runoff quantity affected by impervious surface percentage was the most significant compared to other parameters. Positive correlation between slop and runoff quantity was showed visibly when slop was above 42 degrees. Peak runoff could be affected by characteristic width of sub-catchment.

Design and optimization of acoustic liners with a shear grazing flow: OPAL software platform applications

2021 ◽  
Vol 263 (6) ◽  
pp. 152-163
Author(s):  
Remi Roncen ◽  
Pierre Vuillemin ◽  
Patricia Klotz ◽  
Frank Simon ◽  
Fabien Méry ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Low Frequency ◽  
Small Scale ◽  
Software Platform ◽  
Total Size ◽  
Linearized Euler Equations ◽  
Design And Optimization ◽  
Acoustic Liners ◽  
Frequency Regime ◽  
Grazing Flow

In the context of noise reduction in diverse applications where a shear grazing flow is present (i.e., engine nacelle, jet pump, landing gear), improved acoustic liner solutions are being sought. This is particularly true in the low-frequency regime, where space constraints currently limit the efficiency of classic liner technology. To perform the required multi-objective optimization of complex meta-surface liner candidates, a software platform called OPAL was developed. Its first goal is to allow the user to assemble a large panel of parallel/serial assembly of unit acoustic elements, including the recent concept of LEONAR materials. Then, the physical properties of this liner can be optimized, relatively to given weighted objectives (noise reduction, total size of the sample, weight), for a given configuration. Alternatively, properties such as the different impedances of liner unit surfaces can be optimized. To accelerate the process, different nested levels of optimization are considered, from 0D analytical coarse designs in order to reduce the parameter space, up to 2D plan or axisymmetric high-order Discontinuous Galerkin resolution of the Linearized Euler Equations. The presentation will focus on the different aspects of liner design considered in OPAL, and present an application on different samples made for a small scale aeroacoustic bench.

scholarly journals Simulation of Low Impact Development (LID) Practices and Comparison with Conventional Drainage Solutions

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 640 ◽  
Author(s):  
Ioannis M. Kourtis ◽  
Vassilios A. Tsihrintzis ◽  
Evangelos Baltas
Keyword(s):  
Water Management ◽  
Design Process ◽  
Low Impact Development ◽  
Green Roofs ◽  
Storm Water ◽  
Management Model ◽  
Storm Events ◽  
Storm Water Management Model ◽  
Runoff Volume ◽  
Peak Runoff

The present work aims at quantifying the benefit of Low Impact Development (LID) practices in reducing peak runoff and runoff volume, and at comparing LID practices to conventional stormwater solutions. The hydrologic-hydraulic model used was the Storm Water Management Model (SWMM5.1). The LID practices modeled were: (i) Green roofs; and (ii) Permeable pavements. Each LID was tested independently and compared to two different conventional practices, i.e., sewer enlargement and detention pond design. Results showed that for small storm events LID practices are comparable to conventional measures, in reducing flooding. Overall, smaller storms should be included in the design process.

Poststack impedance inversion considering the diffractive component of the wavefield

Geophysics ◽  
2020 ◽  
Vol 85 (1) ◽  
pp. R11-R28 ◽  
Author(s):  
Kun Xiang ◽  
Evgeny Landa
Keyword(s):  
Specular Reflection ◽  
Low Frequency ◽  
Velocity Model ◽  
Forward Modeling ◽  
Small Scale ◽  
Fracture Detection ◽  
Frequency Model ◽  
New Approach ◽  
Impedance Inversion ◽  
Diffraction Imaging

Seismic diffraction waveform energy contains important information about small-scale subsurface elements, and it is complementary to specular reflection information about subsurface properties. Diffraction imaging has been used for fault, pinchout, and fracture detection. Very little research, however, has been carried out taking diffraction into account in the impedance inversion. Usually, in the standard inversion scheme, the input is the migrated data and the assumption is taken that the diffraction energy is optimally focused. This assumption is true only for a perfectly known velocity model and accurate true amplitude migration algorithm, which are rare in practice. We have developed a new approach for impedance inversion, which takes into account diffractive components of the total wavefield and uses the unmigrated input data. Forward modeling, designed for impedance inversion, includes the classical specular reflection plus asymptotic diffraction modeling schemes. The output model is composed of impedance perturbation and the low-frequency model. The impedance perturbation is estimated using the Bayesian approach and remapped to the migrated domain by the kinematic ray tracing. Our method is demonstrated using synthetic and field data in comparison with the standard inversion. Results indicate that inversion with taking into account diffraction can improve the acoustic impedance prediction in the vicinity of local reflector discontinuities.

scholarly journals Internal tide energy flux over a ridge measured by a co-located ocean glider and moored ADCP

2019 ◽  
Author(s):  
Rob Hall ◽  
Barbara Berx ◽  
Gillian Damerell
Keyword(s):  
Energy Flux ◽  
Large Scale ◽  
Low Frequency ◽  
Internal Tide ◽  
Small Scale ◽  
Potential Density ◽  
The North ◽  
Model Study ◽  
Continental Shelves ◽  
Alternative Approach

Abstract. Internal tide energy flux is an important diagnostic for the study of energy pathways in the ocean, from large-scale input by the surface tide, to small-scale dissipation by turbulent mixing. Accurate calculation of energy flux requires repeated full-depth measurements of both potential density (ρ) and horizontal current velocity (u) over at least a tidal cycle and over several weeks to resolve the internal spring-neap cycle. Typically, these observations are made using full-depth oceanographic moorings that are vulnerable to being fished-out by commercial trawlers when deployed on continental shelves and slopes. Here we test an alternative approach to minimise these risks, with u measured by a low-frequency ADCP moored near the seabed and ρ measured by an autonomous ocean glider holding station by the ADCP. The method is used to measure the M2 internal tide radiating from the Wyville Thompson Ridge in the North Atlantic. The observed energy flux (4.2 ± 0.2 kW m−1) compares favourably with historic observations and a previous numerical model study. Error in the energy flux calculation due to imperfect co-location of the glider and ADCP is estimated by sub-sampling potential density in an idealised internal tide field along pseudorandomly distributed glider paths. The error is considered acceptable (

scholarly journals A Quantity–Quality Model to Assess the Effects of Source Control Stormwater Management on Hydrology and Water Quality at the Catchment Scale

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1415 ◽  
Author(s):  
Abdul Razaq Rezaei ◽  
Zubaidah Ismail ◽  
Mohammad Hossein Niksokhan ◽  
Muhammad Amin Dayarian ◽  
Abu Hanipah Ramli ◽  
...  
Keyword(s):  
Water Quality ◽  
Best Management Practices ◽  
Urban Areas ◽  
Low Impact Development ◽  
Real Field ◽  
Rain Garden ◽  
Quality Model ◽  
Catchment Scale ◽  
Runoff Reduction ◽  
Peak Runoff

The vast development of urban areas has resulted in the increase of stormwater peak runoff and volume. Water quality has also been adversely affected. The best management practices (BMPs) and low impact development (LID) techniques could be applied to urban areas to mitigate these effects. A quantity–quality model was developed to simulate LID practices at the catchment scale using the US Environmental Protection Agency Storm Water Management Model (US EPA SWMM). The purpose of the study was to investigate the impacts of LID techniques on hydrology and water quality. The study was performed in BUNUS catchment in Kuala Lumpur, Malaysia. This study applied vegetated swale and rain garden to assess the model performance at a catchment scale using real field data. The selected LIDs occupied 7% of each subcatchment (of which 40% was swale and 30% was rain garden). The LID removal efficiency was up to 40% and 62% for TN and TSS, respectively. The peak runoff reduction was up to 27% for the rainfall of up to 70 mm, and up to 19% for the rainfall of between 70 and 90 mm, respectively. For the longer storm events of higher than 90 mm the results were not as satisfactory as expected. The model was more effective in peak runoff reduction during the shorter rainfall events. As for the water quality, it was satisfactory in all selected rainfall scenarios.

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