scholarly journals Effect of Independent Variables on Urban Flood Models

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3442 ◽  
Author(s):  
Yanfen Geng ◽  
Baohang Zhu ◽  
Xin Zheng
Keyword(s):  
Land Cover ◽  
Building Blocks ◽  
Model Verification ◽  
Relative Depth ◽  
Return Periods ◽  
Flood Events ◽  
Simulation Accuracy ◽  
Urban Flood ◽  
Independent Variables ◽  
Resolution Model

The simulation accuracy of urban flood models is affected by independent variables describing terrain resolution and artificial land cover. An evaluation of these effects could provide suggestions for the improvement of simulation accuracy when the available terrain resolutions and representation methods of land cover are different. This paper focused on exploring and evaluating these effects on simulation accuracy using two indicators, relative depth accuracy (RDA) and relative area accuracy (RAA). The study area was the Nanjing Jianye district in China, which has experienced extensive urbanization. Designed rainfall (2 and 10 year return periods) and three terrain resolutions (17, 35, and 70 m) were used in this paper. Building blocks (BB), road drainage (RD), and a combination of both (BB + RD) were compared to present the effect of artificial land cover. Real flood events were initially simulated as a model verification case, and hypothetic modeling scenarios were simulated to evaluate the effects of different resolutions and representation methods. The results indicate that the effect of terrain resolutions on simulation accuracy was more obvious than that of artificial land cover in the study area. In this paper, 20–30% higher accuracy could be achieved in the 35 m resolution model with respect to the 70 m resolution model. A relative accuracy of 94% was achieved in the 17 m resolution model when using the BB method, which was 5% higher than that using the RD method. This paper shows that evaluating the effects of terrain resolution and artificial land cover is effective and helpful for improving the simulation accuracy of urban flood models in extensively urbanized districts.

scholarly journals Modelling floods in urban areas and representation of buildings with a method based on adjusted conveyance and storage characteristics

2012 ◽  
Vol 15 (4) ◽  
pp. 1150-1168 ◽  
Author(s):  
Zoran Vojinovic ◽  
Solomon Seyoum ◽  
Mwanaisha H. Salum ◽  
Roland K. Price ◽  
Ahmad K. Fikri ◽  
...  
Keyword(s):  
High Resolution ◽  
Urban Areas ◽  
Real Life ◽  
Building Blocks ◽  
Urban Flood ◽  
Coarse Resolution ◽  
Resolution Model ◽  
Inertia Model ◽  
Depth Relationship

The present paper reviews several approaches that can be used in capturing urban features in coarse resolution two-dimensional (2D) models and it demonstrates the effectiveness of a new approach against the straightforward 2D modelling approach on a hypothetical and a real-life case study work. The case study work addresses the use of coarse grid resolutions in 2D non-inertia models. The 2D non-inertia model used solves continuity and momentum equations over the cells of the coarse model while taking the minimum elevation as a surface level. The volume stored in every cell is calculated as a volume-depth relationship. In order to replicate restriction in conveyances in x–y directions of fine resolution models due to building blocks, the friction values of the coarse-resolution model are adjusted to match the results of the high-resolution model. The work presented in this paper shows the possibility of applying a 2D non-inertia model more effectively in urban flood modelling applications whilst still making use of the high resolution of topographic data that can nowadays be easily acquired.

scholarly journals Prediction Power of Logistic Regression (LR) and Multi-Layer Perceptron (MLP) Models in Exploring Driving Forces of Urban Expansion to Be Sustainable in Estonia

2021 ◽  
Vol 14 (1) ◽  
pp. 160
Author(s):  
Najmeh Mozaffaree Pour ◽  
Tõnu Oja
Keyword(s):  
Land Cover ◽  
Driving Forces ◽  
Urban Expansion ◽  
Network Models ◽  
Influential Factors ◽  
Residential Areas ◽  
Neural Network Models ◽  
Independent Variables ◽  
The Core ◽  
Mlp Model

Estonia mainly experienced urban expansion after regaining independence in 1991. Employing the CORINE Land Cover dataset to analyze the dynamic changes in land use/land cover (LULC) in Estonia over 28 years revealed that urban land increased by 33.96% in Harju County and by 19.50% in Tartu County. Therefore, after three decades of LULC changes, the large number of shifts from agricultural and forest land to urban ones in an unplanned manner have become of great concern. To this end, understanding how LULC change contributes to urban expansion will provide helpful information for policy-making in LULC and help make better decisions for future transitions in urban expansion orientation and plan for more sustainable cities. Many different factors govern urban expansion; however, physical and proximity factors play a significant role in explaining the spatial complexity of this phenomenon in Estonia. In this research, it was claimed that urban expansion was affected by the 12 proximity driving forces. In this regard, we applied LR and MLP neural network models to investigate the prediction power of these models and find the influential factors driving urban expansion in two Estonian counties. Using LR determined that the independent variables “distance from main roads (X7)”, “distance from the core of main cities of Tallinn and Tartu land (X2)”, and “distance from water land (X11)” had a higher negative correlation with urban expansion in both counties. Indeed, this investigation requires thinking towards constructing a balance between urban expansion and its driving forces in the long term in the way of sustainability. Using the MLP model determined that the “distance from existing residential areas (X10)” in Harju County and the “distance from the core of Tartu (X2)” in Tartu County were the most influential driving forces. The LR model showed the prediction power of these variables to be 37% for Harju County and 45% for Tartu County. In comparison, the MLP model predicted nearly 80% of variability by independent variables for Harju County and approximately 50% for Tartu County, expressing the greater power of independent variables. Therefore, applying these two models helped us better understand the causative nature of urban expansion in Harju County and Tartu County in Estonia, which requires more spatial planning regulation to ensure sustainability.

scholarly journals The Interaction of Community around the Forest towards Land Use Tahura Wan Abdul Rachman

2018 ◽  
Vol 6 (3) ◽  
pp. 1
Author(s):  
Yuliana Kristin ◽  
Rommy Qurniati ◽  
Hari Kaskoyo
Keyword(s):  
Land Use ◽  
Correlation Analysis ◽  
Land Cover ◽  
Land Cover Changes ◽  
Land Area ◽  
Forest Protection ◽  
The Real ◽  
Forest Park ◽  
Independent Variables ◽  
Real Relation

Wan Abdul Rachman Forest Park (Tahura WAR) has experienced the fluctuations in land cover changes in each year. It caused by the interaction of community in utilization of Tahura WAR. The purpose of this study was to determine the level of interaction by the community around Tahura WAR and the influenced factors of it. The product moment correlation analysis was used to see the real relation between the independent variables (the level of interaction) and the dependent variable (land area, income, and the number of family dependents). The result showed that the interaction of the community in the Tahura WAR was moderate. It included the activity of community-related in utilization, preservation and forest protection. The level of interaction was influenced by the land area and the income level of the respondents. Keywords: interaction, Tahura WAR, land area, income.

scholarly journals Evaluating seasonal hydrological extremes in mesoscale (pre-)Alpine basins at coarse 0.5° and fine hyperresolution

2019 ◽  
Vol 23 (3) ◽  
pp. 1593-1609 ◽  
Author(s):  
Joost Buitink ◽  
Remko Uijlenhoet ◽  
Adriaan J. Teuling
Keyword(s):  
High Resolution ◽  
Land Cover ◽  
Swiss Alps ◽  
Hydrological Response ◽  
Low Resolution ◽  
Continental Scale ◽  
Wide Range ◽  
Resolution Model ◽  
High Resolution Model ◽  
Basin Response

Abstract. Hydrological models are being applied for impact assessment across a wide range of resolutions. In this study, we quantify the effect of model resolution on the simulated hydrological response in five mesoscale basins in the Swiss Alps using the distributed hydrological model Spatial Processes in Hydrology (SPHY). We introduce a new metric to compare a range of values resulting from a distributed model with a single value: the density-weighted distance (DWD). Model simulations are performed at two different spatial resolutions, matching common practices in hydrology: 500 m × 500 m matching regional-scale models, and 40 km × 40 km matching global-scale modeling. We investigate both the intra-basin response in seasonal streamflow and evapotranspiration from the high-resolution model and the difference induced by the two different spatial resolutions, with a focus on four seasonal extremes, selected based on temperature and precipitation. Results from the high-resolution model show that the intra-basin response covers a surprisingly large range of anomalies and show that it is not uncommon to have both extreme positive and negative flux anomalies occurring simultaneously within a catchment. The intra-basin response was grouped by land cover, where different dominant runoff-generating processes are driving the differences between these groups. The low-resolution model failed to capture the diverse and contrasting response from the high-resolution model, since neither the complex topography nor land cover classes were properly represented. DWD values show that, locally, the hydrological response simulated with a high-resolution model can be a lot more extreme than a low-resolution model might indicate, which has important implications for global or continental scale assessments carried out at coarse grids of 0.5∘×0.5∘ or 0.25∘×0.25∘ resolution.

High-resolution model Verification Evaluation (HiVE). Part 1: Using neighbourhood techniques for the assessment of ocean model forecast skill

2020 ◽  
Author(s):  
Jan Maksymczuk ◽  
Ric Crocker ◽  
Marion Mittermaier ◽  
Christine Pequignet
Keyword(s):  
High Resolution ◽  
Weather Prediction ◽  
Ocean Model ◽  
Forecast Skill ◽  
Model Verification ◽  
Model Forecast ◽  
Verification Methods ◽  
Resolution Model ◽  
The Right ◽  
Spatial Verification

<div> <p>HiVE is a CMEMS funded collaboration between the atmospheric Numerical Weather Prediction (NWP) verification and the ocean community within the Met Office, aimed at demonstrating the use of spatial verification methods originally developed for the evaluation of high-resolution NWP forecasts, with CMEMS ocean model forecast products. Spatial verification methods provide more scale appropriate ways to better assess forecast characteristics and accuracy of km-scale forecasts, where the detail looks realistic but may not be in the right place at the right time. As a result, it can be the case that coarser resolution forecasts verify better (e.g. lower root-mean-square-error) than the higher resolution forecast. In this instance the smoothness of the coarser resolution forecast is rewarded, though the higher-resolution forecast may be better. The project utilised open source code library known as Model Evaluation Toolkit (MET) developed at the US National Center for Atmospheric Research. </p> </div><div> <p> </p> </div><div> <p>This project saw, for the first time, the application of spatial verification methods to sub-10 km resolution ocean model forecasts. The project consisted of two parts. Part 1 describes an assessment of the forecast skill for SST of CMEMS model configurations at observing locations using an approach called HiRA (High Resolution Assessment). Part 2 is described in the companion poster to this one.  </p> </div><div> <p> </p> </div><div> <p>HiRA is a single-observation-forecast-neighbourhood-type method which makes use of commonly used ensemble verification metrics such as the Brier Score (BS) and the Continuous Ranked Probability Score (CRPS). In this instance all model grid points within a predefined neighbourhood of the observing location are considered equi-probable outcomes (or pseudo-ensemble members) at the observing location. The technique allows for an inter-comparison of models with different grid resolutions as well as between deterministic and probabilistic forecasts in an equitable and consistent way. In this work it has been applied to the CMEMS products delivered from the AMM7 (~7km) and AMM15 (~1.5km) model configurations for the European North West Shelf that are provided by the Met Office. </p> </div><div> <p> </p> </div><div> <p>It has been found that when neighbourhoods of equivalent extent are compared for both configurations it is possible to show improved forecast skill for SST for the higher resolution AMM15 both on- and off-shelf, which has been difficult to demonstrate previously using traditional metrics. Forecast skill generally degrades with increasing lead time for both configurations, with the off-shelf results for the higher resolution model showing increasing benefits over the coarser configuration. </p> </div>

scholarly journals Modelling and assessment of urban flood hazards based on rainfall intensity-duration-frequency curves reformation

2016 ◽  
Author(s):  
Reza Ghazavi ◽  
Ali Moafi Rabori ◽  
Mohsen Ahadnejad Reveshty
Keyword(s):  
Return Period ◽  
Urban Areas ◽  
Rainfall Intensity ◽  
Flood Hazards ◽  
Return Periods ◽  
Urban Flood ◽  
Design Storm ◽  
Hourly Rainfall ◽  
Idf Curves ◽  
Intensity Duration Frequency

Abstract. Estimate design storm based on rainfall intensity–duration–frequency (IDF) curves is an important parameter for hydrologic planning of urban areas. The main aim of this study was to estimate rainfall intensities of Zanjan city watershed based on overall relationship of rainfall IDF curves and appropriate model of hourly rainfall estimation (Sherman method, Ghahreman and Abkhezr method). Hydrologic and hydraulic impacts of rainfall IDF curves change in flood properties was evaluated via Stormwater Management Model (SWMM). The accuracy of model simulations was confirmed based on the results of calibration. Design hyetographs in different return periods show that estimated rainfall depth via Sherman method are greater than other method except for 2-year return period. According to Ghahreman and Abkhezr method, decrease of runoff peak was 30, 39, 41 and 42 percent for 5-10-20 and 50-year return periods respectively, while runoff peak for 2-year return period was increased by 20 percent.

scholarly journals Remote sensing and GIS application for river runoff and water quality modeling in a hilly forested watershed of Japan

2010 ◽  
Vol 13 (2) ◽  
pp. 198-216 ◽  
Author(s):  
Binaya R. Shivakoti ◽  
Shigeo Fujii ◽  
Shuhei Tanaka ◽  
Hirotaka Ihara ◽  
Masashi Moriya
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Land Cover ◽  
Spatial Information ◽  
Remote Sensing And Gis ◽  
Water Quality Modeling ◽  
Model Verification ◽  
Modeling Framework ◽  
Area Index ◽  
Distributed Modeling

The main objective of this study is to present a simplified distributed modeling framework based on the storage balance concept of a Tank Model and by utilizing inputs from remote sensing data and GIS analysis. The modeling process is simplified by (1) minimizing the number of parameters with unknown values and 2) retaining important characteristics (such as land cover, topography, geology) of the study area in order to account for spatial variability. Remote sensing is used as a main source of distributed data and the GIS environment is used to integrate spatial information into the model. Remote sensing is utilized mainly to derive land cover, leaf area index (Lai) and transpiration coefficient (Tc). Topographic variables such as slope, drainage direction and soil topographic index (Tindex) are derived from a digital elevation model (DEM) using GIS. The model is used to estimate evapotranspiration (Et) loss, river flow rate and selected water quality parameters (CODMn and TP). Model verification adopted a comparison of estimated results with observed data collected at different temporal scales (storm events, daily, alternate days and every 10 days). A simplified distributed modeling framework coupled with remote sensing and GIS is expected to be an alternative to complex distributed modeling processes, which required values of parameters usually unavailable at a grid scale.

scholarly journals Assessing changes on urban flood vulnerability through mapping land use from historical information

2015 ◽  
Vol 12 (6) ◽  
pp. 6151-6177 ◽  
Author(s):  
M. Boudou ◽  
B. Danière ◽  
M. Lang
Keyword(s):  
Land Use ◽  
Flood Risk ◽  
Local Scale ◽  
Flood Events ◽  
Historical Sources ◽  
Flood Vulnerability ◽  
Urban Flood ◽  
Xxth Century ◽  
Historical Information ◽  
Significant Events

Abstract. This paper presents a diachronic appraisal of flood vulnerability of two French cities, respectively Besançon and Moissac, which have been largely impacted by two ancient floods in January 1910 and March 1930. Both flood events figured among the most significant events recorded in France during the XXth century. An analysis of historical sources allows the mapping of land use and occupation within the flood extent of the two historical floods, both in past and present contexts. It gives an insight of the complexity of flood risk evolution, at a local scale.

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