scholarly journals Two Dimensional Model for Backwater Geomorphology: Darby Creek, PA

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2204 ◽  
Author(s):  
Hosseiny ◽  
Smith
Keyword(s):  
Urban Areas ◽  
Water Surface ◽  
Integrated Model ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Morphological Alterations ◽  
Digital Elevation ◽  
Starting Point ◽  
Spatio Temporal ◽  
Elevation Model

Predicting morphological alterations in backwater zones has substantial merit as it potentially influences the life of millions of people by the change in flood dynamics and land topography. While there is no two-dimensional river model available for predicting morphological alterations in backwater zones, there is an absolute need for such models. This study presents an integrated iterative two-dimensional fluvial morphological model to quantify spatio-temporal fluvial morphological alterations in normal flow to backwater conditions. The integrated model works through the following steps iteratively to derive geomorphic change: (1) iRIC model is used to generate a 2D normal water surface; (2) a 1D water surface is developed for the backwater; (3) the normal and backwater surfaces are integrated; (4) an analytical 2D model is established to estimate shear stresses and morphological alterations in the normal, transitional, and backwater zones. The integrated model generates a new digital elevation model based on the estimated erosion and deposition. The resultant topography then serves as the starting point for the next iteration of flow, ultimately modeling geomorphic changes through time. This model was tested on Darby Creek in Metro-Philadelphia, one of the most flood-prone urban areas in the US and the largest freshwater marsh in Pennsylvania.

scholarly journals Environmental monitoring of soil pollution in urban areas (a case study from Heraklion city, Central Crete, Greece)

2017 ◽  
Vol 47 (2) ◽  
pp. 963
Author(s):  
E. Kokinou ◽  
C. Belonaki ◽  
D. Sakadakis ◽  
K. Sakadaki
Keyword(s):  
Magnetic Susceptibility ◽  
Urban Areas ◽  
Magnetic Measurements ◽  
Topographic Map ◽  
Near Surface ◽  
Thermomagnetic Analysis ◽  
Geological Features ◽  
Digital Elevation ◽  
Elevation Model

Main scope of the present study is to combine topographic and geological data, magnetic susceptibility and thermomagnetic analysis in order to investigate the magnetic properties of the near surface soils in possible polluted urban areas. For this purpose, a power plant with a dense traffic net around it, located in the NW section of Heraklion city in Crete was selected to be the study area. Surface soil samples have been collected from the area under investigation and they were analyzed in order to estimate the spatial distribution of the magnetic susceptibility. Loci of high values of the magnetic susceptibility within the study area gave rise to further proceed to thermomagnetic analysis of the selected samples. GIS techniques were used for mapping the magnetic measurements on the various topographic and geological features of the area. The digital elevation model was created by the digitization of the topographic map contours (1:5000 scale maps). The combination of the above techniques indicate high values of the magnetic susceptibility especially in the northeastern part of the investigated area, possibly related to pollution due to the presence of heavy metals.

scholarly journals Spatial Analysis Using Temporal Point Clouds in Advanced GIS: Methods for Ground Elevation Extraction in Slant Areas and Building Classifications

2019 ◽  
Vol 8 (3) ◽  
pp. 120 ◽  
Author(s):  
Sara Shirowzhan ◽  
Samad Sepasgozar
Keyword(s):  
Digital Elevation Model ◽  
Urban Growth ◽  
Urban Areas ◽  
Future Directions ◽  
3D Data ◽  
Contour Lines ◽  
Digital Elevation ◽  
The Future ◽  
Elevation Model ◽  
Skewness And Kurtosis

Deriving 3D urban development patterns is necessary for urban planners to control the future directions of 3D urban growth considering the availability of infrastructure or being prepared for fundamental infrastructure. Urban metrics have been used so far for quantification of landscape and land-use change. However, these studies focus on the horizontal development of urban form. Therefore, questions remain about 3D growth patterns. Both 3D data and appropriate 3D metrics are fundamentally required for vertical development pattern extraction. Airborne light detection and ranging (Lidar) as an advanced remote-sensing technology provides 3D data required for such studies. Processing of airborne lidar to extract buildings’ heights above a footprint is a major task and current automatic algorithms fail to extract such information on vast urban areas especially in hilly sites. This research focuses on proposing new methods of extraction of ground points in hilly urban areas using autocorrelation-based algorithms. The ground points then would be used for digital elevation model generation and elimination of ground elevation from classified buildings points elevation. Technical novelties in our experimentation lie in choosing a different window direction and also contour lines for the slant area, and applying moving windows and iterating non-ground extraction. The results are validated through calculation of skewness and kurtosis values. The results show that changing the shape of windows and their direction to be narrow long squares parallel to the ground contour lines, respectively, improves the results of classification in slant areas. Four parameters, namely window size, window shape, window direction and cell size are empirically chosen in order to improve initial digital elevation model (DEM) creation, enhancement of the initial DEM, classification of non-ground points and final creation of a normalised digital surface model (NDSM). The results of these enhanced algorithms are robust for generating reliable DEMs and separation of ground and non-ground points in slant urban scenes as evidenced by the results of skewness and kurtosis. Offering the possibility of monitoring urban growth over time with higher accuracy and more reliable information, this work could contribute in drawing the future directions of 3D urban growth for a smarter urban growth in the Smart Cities paradigm.

scholarly journals Flood depth estimation by means of high-resolution SAR images and LiDAR data

2018 ◽  
Author(s):  
Fabio Cian ◽  
Mattia Marconcini ◽  
Pietro Ceccato ◽  
Carlo Giupponi
Keyword(s):  
High Resolution ◽  
Urban Areas ◽  
Depth Estimation ◽  
Flood Depth ◽  
Inundation Depth ◽  
Detection Approach ◽  
Digital Elevation ◽  
Radar Imagery ◽  
Elevation Model ◽  
Terrain Elevation

Abstract. When floods hit inhabited areas, great losses are usually registered both in terms of impacts on people (i.e., fatalities and injuries) as well as economic impacts on urban areas, commercial and productive sites, infrastructures and agriculture. To properly assess these, several parameters are needed among which flood depth is one of the most important as it governs the models used to compute damages in economic terms. This paper presents a simple yet effective semi-automatic approach for deriving very precise inundation depth. First, precise flood extent is derived employing a change detection approach based on the Normalized Difference Flood Index computed from high resolution Synthetic Aperture Radar imagery. Second, by means of a high-resolution Light Detection And Ranging Digital Elevation Model, water surface elevation is estimated through a statistical analysis of terrain elevation along the boundary lines of the identified flooded areas. Experimental results and quality assessment are given for the flood occurred in the Veneto region, North-Eastern Italy, in 2010. In particular, the method proved fast and robust and, compared to hydrodynamic models, it requires sensibly less input information.

scholarly journals Modelling the Structure of Terrestrial Landscapes in Urban Areas

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Natalya Krutskikh
Keyword(s):  
Urban Areas ◽  
Complex Structure ◽  
Topographic Position Index ◽  
Digital Elevation ◽  
Geochemical Landscapes ◽  
Position Index ◽  
Type Of Land Use ◽  
Elevation Model ◽  
Internal And External Factors ◽  
The City

Abstract The study of internal and external factors in the formation of an urban geosystem is determined by its complex structure and multiple connections. Based on geoinformation modelling, an analysis of the landscape structure of the city territory is carried out, which can be a basis for further geoecological research. Morphometric indicators, which make it possible to determine the elementary geochemical landscapes, are indicated according to the data of the digital elevation model. A standardised topographic position index (TPI) is used to determine locations. Spatial zoning according to the type of land use reflects the qualitative features of the external load and technogenic impact. The data on the composition of the lithogenic base show the properties of the depositing medium and determine the natural background. Number of categories of landscapes identified are 58, characterised by a homogeneous geological composition, technogenic load and conditions for the migration of matter. The ratios of various landscape zones have been calculated. The study area as a whole is characterised by the predominance of migration processes over accumulation.

scholarly journals Terrain Representation and Distinguishing Ability of Roughness Algorithms Based on DEM with Different Resolutions

2019 ◽  
Vol 8 (4) ◽  
pp. 180 ◽  
Author(s):  
Jiang Wu ◽  
Junjie Fang ◽  
Jiangbo Tian
Keyword(s):  
Research Area ◽  
Continuous Wavelet ◽  
Two Dimensional ◽  
Digital Elevation ◽  
Terrain Parameters ◽  
Terrain Representation ◽  
Elevation Model ◽  
Better Than ◽  
Deviation Method ◽  
Statistical Criteria

Digital elevation model (DEM) resolution is closely related to the degree of expression of real terrain, the extraction of terrain parameters, and the uncertainty of statistical models. Therefore, based on DEMs with various resolutions, this paper explores the representation and distinguishing ability of different roughness algorithms to measure terrain parameters. Fuyang, a district of Hangzhou City with various landform types, was selected as the research area. Slope, root mean squared height, vector deviation, and two-dimensional continuous wavelet transform were selected as four typical roughness algorithms. The resolutions used were 5, 10, 25, and 50 m DEM on the scale for plains, hills, and mountainous areas. The statistical criteria of effect size and entropy were used as indicators to evaluate and analyze the different roughness algorithms. The results show that in terms of these measures: (1) The expression ability of the SLOPE and root mean squared height (RMSH) algorithms is better than that of the vector deviation method, while the two-dimensional continuous wavelet method based on frequency analysis emphasizes the terrain information within a certain range. (2) The terrain distinguishing ability of the SLOPE and RMSH is not sensitive to the changes in resolution, with the other two algorithms varying with the changes in resolution.

scholarly journals A Generalized Automated Framework for Urban Runoff Modeling and Its Application at a Citywide Landscape

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 357 ◽  
Author(s):  
Hossein Hosseiny ◽  
Michael Crimmins ◽  
Virginia B. Smith ◽  
Peleg Kremer
Keyword(s):  
Urban Areas ◽  
Urban Landscape ◽  
Negative Effects ◽  
Inundation Maps ◽  
Digital Elevation ◽  
Management And Development ◽  
Peak Runoff ◽  
Resources Conservation ◽  
Elevation Model ◽  
Runoff Discharge

This research presents a fully automated framework for runoff estimation, applied to Philadelphia, Pennsylvania, a major urban area. Trends in global urbanization are exacerbating stormwater runoff, making it an increasingly critical challenge in urban areas. Understanding the fine-scale spatial distribution of local flooding is difficult due to the complexity of the urban landscape and lack of measured data, but it is critical for urban management and development. A one-meter resolution Digital Elevation Model (DEM) was used in conjunction with a model developed by using ArcGIS Pro software to create urban micro-subbasins. The DEM was manipulated to account for roof drainage and stormwater infrastructure, such as inlets. The generated micro-subbasins paired with 24-h storm data with a 10-year return period taken from the National Resources Conservation Service (NRCS) for the Philadelphia area was used to estimate runoff. One-meter land-cover and land-use data were used to estimate pervious and impervious areas and the runoff coefficients for each subbasin. Peak runoff discharge and runoff depth for each subbasin were then estimated by the rational and modified rational methods and the NRCS method. The inundation depths from the NRCS method and the modified rational method models were compared and used to generate percent agreement, maximum, and average of inundation maps of Philadelphia. The outcome of this research provides a clear picture of the spatial likelihood of experiencing negative effects of excessive precipitation, useful for stormwater management agencies, city managers, and citizen.

scholarly journals Analysis of the Flood Performance of Stormwater Drainage Systems for Different Return Periods

2021 ◽  
Author(s):  
Burak ÇIRAĞ ◽  
◽  
Mahmut FIRAT ◽  
Özgüray AYDIN ◽  
◽  
...  
Keyword(s):  
Urban Areas ◽  
Application Area ◽  
Drainage Systems ◽  
Irregular Structures ◽  
Digital Elevation ◽  
Precipitation Behaviour ◽  
Precipitation Regimes ◽  
Natural Streams ◽  
Drainage Line ◽  
Elevation Model

Precipitation regimes and behaviours change depending on the climate change. As the duration of precipitation decreases its intensity increases. On the other hand, the density of buildings increases in urban areas, and drainage systems remain inadequate as a result of deterioration in the structure of natural streams and irregular structures. Due to the change in precipitation behaviour and the decrease in permeable surfaces in urban areas, urban floods lead to serious damage. In this study, it is aimed to analyse the flood performance of rainwater drainage systems currently serving in urban areas for precipitation with different repetition periods. For this purpose, the drainage line in Malatya provincial centre has been selected as the pilot application area. Considering the rainfall records observed in the past, a model was created for 15 minutes of precipitation and 2, 5 and 10 years repetition periods. In addition, the digital elevation model, drainage line and characteristic information and building layouts were taken into consideration in the application area. As a result of the analysis, flood spread maps were created. It has been observed that as the repetition period increases, the rainwater drainage line is insufficient in some areas and may cause loss of property and life.

scholarly journals Hydrological and hydraulic models for determination of flood-prone and flood inundation areas

2016 ◽  
Vol 373 ◽  
pp. 137-141 ◽  
Author(s):  
Hafzullah Aksoy ◽  
Veysel Sadan Ozgur Kirca ◽  
Halil Ibrahim Burgan ◽  
Dorukhan Kellecioglu
Keyword(s):  
Cross Sections ◽  
Urban Areas ◽  
Work Load ◽  
Hydraulic Model ◽  
Flood Inundation ◽  
Detailed Data ◽  
Wetness Index ◽  
Digital Elevation ◽  
Elevation Model ◽  
Flood Prone Areas

Abstract. Geographic Information Systems (GIS) are widely used in most studies on water resources. Especially, when the topography and geomorphology of study area are considered, GIS can ease the work load. Detailed data should be used in this kind of studies. Because of, either the complication of the models or the requirement of highly detailed data, model outputs can be obtained fast only with a good optimization. The aim in this study, firstly, is to determine flood-prone areas in a watershed by using a hydrological model considering two wetness indexes; the topographical wetness index, and the SAGA (System for Automated Geoscientific Analyses) wetness index. The wetness indexes were obtained in the Quantum GIS (QGIS) software by using the Digital Elevation Model of the study area. Flood-prone areas are determined by considering the wetness index maps of the watershed. As the second stage of this study, a hydraulic model, HEC-RAS, was executed to determine flood inundation areas under different return period-flood events. River network cross-sections required for this study were derived from highly detailed digital elevation models by QGIS. Also river hydraulic parameters were used in the hydraulic model. Modelling technology used in this study is made of freely available open source softwares. Based on case studies performed on watersheds in Turkey, it is concluded that results of such studies can be used for taking precaution measures against life and monetary losses due to floods in urban areas particularly.

3D geological modelling of the western Aar Massif (external Central Alps, Switzerland)

2020 ◽  
Author(s):  
Ferdinando Musso Piantelli ◽  
Marco Herwegh ◽  
Alfons Berger ◽  
Michael Wiederkehr ◽  
Eva Kurmann ◽  
...  
Keyword(s):  
Digital Elevation Model ◽  
Cross Sections ◽  
3D Model ◽  
Two Dimensional ◽  
Central Alps ◽  
Digital Elevation ◽  
Geological Information ◽  
Aar Massif ◽  
Elevation Model ◽  
Tectonic Boundaries

<p>3D modelling of complex and irregular geological bodies is an expanding discipline that combines two-dimensional cartographic and structural data managed with GIS technology. This study presents a complete workflow developed to process geological information to build a 3D model of major stratigraphic, structural and tectonic boundaries. The investigated area is located in the western part of the Aar Massif (external Central Alps, Switzerland) characterized by pronounced topographic (600–<4000 m) relief, making it prone for surface based 3D depth constructions. The workflow comprises four major steps:</p><p>(1)  <strong>Generation of 2D polylines in a map view</strong>: a two-dimensional dataset of sequences of polylines has been generated in ArcGIS (10.3.1) defining the starting dataset for the major stratigraphic and tectonic boundaries of the bedrock units. This dataset has been compiled and integrated by using: (i) GeoCover vector datasets 1:25 000 of the Swiss Geological Survey; (ii) The Geological Special Map 1:100 000 of the Aar Massif and the Tavetsch and Gotthard Nappes of the Swiss Geological Survey; (iii) data from literature; and (iv) additional field work conducted for this study in key-locations.</p><p>(2) <strong>Projection of 2D information onto 3D digital elevation model</strong>: with the 3D structural modelling software Move (Petex/Midland Valley; 2019.1) the boundaries have then been projected on a digital elevation model (swissALTI3D) with 2 m resolution.</p><p>(3) <strong>Construction of tectonic cross sections</strong>: the use of geometric arguments as well as structural measurements allows for projection of these boundaries into a dense regularly spaced network of 2D cross-sections.</p><p>(4) <strong>Interpolation of 3D surfaces</strong>: the surface and cross-sections boundaries can be interpolated by applying 3D projection and meshing techniques resulting in a final 3D structural model.</p><p>Generally, steps (2–4) require iterative adaptations particularly in the case of surface areas being covered by glaciers or unconsolidated Quaternary sediments. In the model, special emphasis is given to visualize the current structural disposition of the western Aar Massif as well as the relative geometric and overprinting relationships of the deformation sequence that shaped the investigated area throughout the Alpine deformation. Finally, since in the investigated area underground data are scarce, an assessment of the relative uncertainties related to input data and is intended to be performed following the approach proposed by Baumberger (2014) and Ferńandez (2005). The workflow presented here offers the chance to gain validation approaches for domains only weakly constrained or with no surface data available, by generating a 3D model that integrates all accessible geological information and background knowledge.</p><p> </p><p>REFERENCES</p><p>Baumberger, R. (2014): Quantification of Lineaments: Link between internal 3D structure and surface evolution 328 of the Hasli valley (Aar massif, central alps, Switzerland), University of Bern, PhD Thesis, unpublished.</p><p>Ferńandez, O. (2005): Obtaining a best fitting plane through 3D georeferenced data, Journal of Structural Geology 27, pp. 855–858</p>

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