Analysis of Hydraulic Risk Territories: Comparison Between LIDAR and Other Different Techniques for 3D Modeling (original) (raw)
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Aim of this paper is investigation of a possible use of the technique of LIDAR topographic survey for updating existing hydraulic models for the calculation of Hydraulic head for risk areas. Specifically, this study intends to assess the benefits to be gained from new methods of LIDAR detection comparing calculations and simulations of updated models with those obtained from existing models, highlighting the critical issues of the use made for hydraulic analysis. We also carried out a comparison on the accuracy obtainable from DEM generated with different methods of acquisition and processing.
Lidar for Analysis of Hydraulic Risk Territories
Advances in Environmental and Geological Science and Engineering - Proceedings of the 8th International Conference on Environmental and Geological Science and Engineering (EG '15) Salerno, Italy June 27-29, 2015, 2015
This paper investigates a possible use of the technique of LIDAR topographic survey for updating existing hydraulic models for the calculation of Hydraulic head for risk areas. The study, in particular, tends to assess the benefits to be gained from new methods of LIDAR detection comparing calculations and simulations of updated models with those obtained from existing models and also highlighting the critical issues of the use made for hydraulic analysis.
Integration of Lidar and 3D Modelling for the Analysis of a Flooding Event
ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2013
Laser scanner technology can be very useful for applications relative to surveying river-beds with high and very high resolution (sampling heights at one meter spacing or less). A 3D model of structures including the river-bed, sides and contiguous areas allows to develop rigorous hydraulic models relative to flooding predictions and to the estimation of relative damages. In the field of hydraulic modelling, an important role has been played by 3D modelling when the flooding of the Bacchiglione River in 2010. Laser scanner techniques have been used for the rapid and accurate definition of which areas are prone to high risk and to potential damage in the case of bursting of river banks. The results allow estimating the amount of safety in particular cases which depend on the presence of natural and/or artificial protection structures which prevent devastation of houses or other human-made artefacts by acting as an obstacle to the water flow.
The work stems from a joint study between the Laboratory ASTRO (Department of Civil and Industrial Engineering -University of Pisa), the municipality of Pisa and the province of Arezzo on the advanced analysis and use of digital elevation data. Besides, it is framed in the research carried on by ASTRO about the definition of the priority informative layers for emergency management in the territory, as of PRIN 2008. Specifically, this work is in continuity with other already published results concerning rigorous accuracy checks of LIDAR data and testing of the procedures to transform raw data in formats consistent with CTR and survey data. The analysis of sections of riverbed, derived from interpolation by DTMs featuring different grid density with those detected topographically, is presented. Validation by differential GNSS methodology of the DTMs used showed a good overall quality of the model for open, low-sloping areas. Analysis of the sections, however, has shown that the representation of small or high-sloping (ditches, embankments) morphological elements requires a high point density such as in laser scanner surveys, and a small mesh size of the grid. In addition, the correct representation of riverside structures is often hindered by the presence of thick vegetation and poor raw LIDAR data filtering.
An Overall View of Lidar and Sonar Systems Used in Geomatics Applications for Hydrology
2018
The paper presents an overall view of LiDAR and Sonar systems used in geomatics applications for hydrology, this branch of science concerning with the properties of the earth's water, and especially its movement in relation to land. LiDAR sensor provides an efficient, rapid, and low cost tool for hydrological application, especially for coastal and river water management. For example, in Romania the hydrographic organizations need accurate bathymetric maps for near coastline area of the Black Sea, for the Danube River and the inner riversides. Nowadays, airborne LiDAR bathymetry is an accurate, capable, and highly cost-effective alternative to traditional waterborne Sonar in areas with appropriate depth and water clarity Water hydrology modelling and watershed management is based on constant monitoring of the water volume over a long time for modelling water dynamic behavior. Flood prediction and flood extend modelling is one of the most important issues in the watershed managem...
Flood risk modelling with LiDAR technology
Floods are one of the most serious, common and costly natural disasters that many countries are facing. Climate change and growing urban areas have dramatically increased the frequency and the severity of flood events. This has enhanced the interest of the Scientific Community and of public institutions into creating more accurate studies regarding the delineation of possible flood areas. In mountain and hill areas, it is much easier to mark the flood areas even with a one-dimensional scheme, while in lowlands the accurate delimitation of flood areas becomes much more difficult requiring a more detailed description of the territory. In particular, the definition of flood areas in costal zones is extremely difficult because of the small changes in the land surface elevation and because of the presence of manmade structures that may significantly modify flood distribution. The area of study is the Ionian coastal plain of the Basilicata region (Southern Italy) crossed by five of the six main rivers of the region (Bradano, Basento, Cavone, Agri and Sinni). This work aims to: analyze the capacity of LaserScan data for the description of coastal morphology and to model flood risk areas; define a DTM able to describe the channel and floodplain morphology working on high resolution laser altimetry data and topographic data; define the most effective strategy for the delineation of flood areas using the comparison of one dimensional model (Hec-Ras developed by the Hydrologic Engineering Center of USACE) versus the two dimensional scheme (MIKE 21 HD by the Danish Hydraulic Institute, FLO-2D by J. S. O'Brien [1], FLATModel by V.Medina et al. [2].
Flood mapping using LIDAR DEM. Limitations of the 1-D modeling highlighted by the 2-D approach
Natural Hazards, 2015
Nowadays, the use of 2-D fully dynamic models represents the most reliable approach for flood inundation and flood hazard studies, especially in complex applications. However, 1-D modeling is still a widely used approach due to the reduced computational time and cost. The introduction of LIDAR technique has stimulated a more detailed topographic description of river reaches. As a result, this huge amount of topographic data can lead to significant improvements in the 1-D computations. Therefore, the main purpose of this paper is to realize how the improvements in the topographic description can reduce the difference between 1-D and 2-D models, highlighting at the same time the critical aspects and the limitations of 1-D approach in the hydraulic simulation as well as in the spatial representation of the results. The analysis presented in the paper refers to two actual case studies for which terrestrial and airborne LIDAR DEMs were collected on purpose. The results of those applications show that the use of 1-D models requires a greater hydraulic skilfulness than the use of 2-D model.
Lidar Data Resolution Versus Hydro-Morphological Models for Flood Risk Assessment
ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2014
Uncertainties in topographic data have a significant influence on hydro-morphological and hydraulic predictions and therefore on flood risk assessment. In this work, the effects of topographic data resolution on the results of hydro-morphologic and hydraulic simulations are analysed using respectively the morphological bi-dimensional curvilinear model MIKE 21C and mono-bidimensional SOBEK. The studies have been carried out in the Torre river, located in Northern Italy. The evaluations on hydro-morphological and hydraulic risk require accurate spatial information for the area of interest. In order to characterize the river morphology, mainly for large areas, the availability of high resolution topography derived by airborne laser scanner represents an effective tool. Nowadays LiDAR (Light Detection And Ranging) DTM covering large areas are readily available for public authorities, and there is a greater and more widespread interest in the application of such information for the devel...