scholarly journals GIS Framework for Spatiotemporal Mapping of Urban Flooding

Geosciences ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 77 ◽  
Author(s):  
Sayed Abedin ◽  
Haroon Stephen
Keyword(s):  
Spatiotemporal Mapping ◽  
Dem Resolution ◽  
News Reports ◽  
Digital Elevation ◽  
Parking Lot ◽  
Storm Drain ◽  
Elevation Model ◽  
Flood Dynamics ◽  
The University ◽  
Runoff Hydrographs

This research aims to develop a framework using the Geographic Information System (GIS) to perform modeling and mapping of flood spatiotemporal variation in urban micro-watersheds. The GIS-framework includes a workflow of several methods and processes including delineation of urban watershed, generation of runoff hydrographs, and time series mapping of inundation depths and flood extent. This framework is tested in areas previously known to have experienced flooding at the University of Nevada, Las Vegas main campus, including Black Parking Lot (Blacklot) and East Mall. Calibration is performed by varying Digital Elevation Model (DEM) resolution, rainfall temporal resolution, and clogging factor whereas validation is performed using flood information from news reports and photographs. The testing at the Blacklot site resulted in calibration at 5 m DEM resolution and clogging factor of 0.83. The flood model resulted in an error of 24% between the estimated (26 inches/66 cm) and actual (34 inches/86.36 cm) flood depths. The estimated flood extents are consistent with the reported conditions and observed watermarks in the area. The flood beginning time estimated from the model is also consistent with the news reports. The testing at East Mall site also shows consistent results. The GIS framework provides spatiotemporal maps of flood inundation for visualization of flood dynamics. This research provides insight into flood modeling and mapping for a storm drain inlet-based watershed.

scholarly journals Evaluation of Reliable Digital Elevation Model Resolution for TOPMODEL in Two Mountainous Watersheds, South Korea

2019 ◽  
Vol 9 (18) ◽  
pp. 3690 ◽  
Author(s):  
Daeryong Park ◽  
Huan-Jung Fan ◽  
Jun-Jie Zhu ◽  
Sang-Eun Oh ◽  
Myoung-Jin Um ◽  
...  
Keyword(s):  
South Korea ◽  
Cell Size ◽  
Digital Elevation Model ◽  
River Basin ◽  
Grid Cell ◽  
Dem Resolution ◽  
Digital Elevation ◽  
Mountainous Watersheds ◽  
Elevation Model ◽  
Digital Elevation Model Resolution

This study analyzed the result of parameter optimization using the digital elevation model (DEM) resolution in the TOPography-based hydrological MODEL (TOPMODEL). Also, this study investigated the sensitivity of the TOPMODEL efficiency by applying the varying resolution of the DEM grid cell size. This work applied TOPMODEL to two mountainous watersheds in South Korea: the Dongkok watershed in the Wicheon river basin and the Ieemokjung watershed in the Pyeongchang river basin. The DEM grid cell sizes were 5, 10, 20, 40, 80, 160, and 300 m. The effect of DEM grid cell size on the runoff was investigated by using the DEM grid cell size resolution to optimize the parameter sets. As the DEM grid cell size increased, the estimated peak discharge was found to increase based on different parameter sets. In addition, this study investigated the DEM grid cell size that was most reliable for use in runoff simulations with various parameter sets in the experimental watersheds. The results demonstrated that the TOPMODEL efficiencies in both the Dongkok and Ieemokjung watersheds rarely changed up to a DEM grid-size resolution of about 40 m, but the TOPMODEL efficiencies changed with the coarse resolution as the parameter sets were changed. This study is important for understanding and quantifying the modeling behaviors of TOPMODEL under the influence of DEM resolution based on different parameter sets.

scholarly journals Effects of digital elevation model resolution on topography-based runoff simulation under uncertainty

2014 ◽  
Vol 16 (6) ◽  
pp. 1343-1358 ◽  
Author(s):  
L. Cui ◽  
Y. P. Li ◽  
G. H. Huang ◽  
Y. Huang
Keyword(s):  
Water Resources ◽  
Digital Elevation Model ◽  
Water Resources Management ◽  
Rainfall Runoff ◽  
Runoff Simulation ◽  
Resources Management ◽  
Dem Resolution ◽  
Analysis Technique ◽  
Digital Elevation ◽  
Elevation Model

Topography plays a critical role in controlling water dispersion and soil movement in hydrologic modeling for water resources management with raster-based digital elevation model (DEM). This study aims to model effects of DEM resolution on runoff simulation through coupling fuzzy analysis technique with a topography based rainfall–runoff model (TOPMODEL). Different levels of DEM grid sizes between 30 m and 200 m are examined, and the results indicate that 30 m DEM resolution is the best for all catchments. Results demonstrate that the DEM resolution could have significant influence on the TOPMODEL rainfall–runoff simulation. Fuzzy analysis technique is used to further examine the uncertain DEM resolution based on considering Nash, sum of squared error, and sum of absolute error values of TOPMODEL. The developed model is calibrated and validated against observed flow during the period 2010–2012, and generally performed acceptably for model Nash–Sutcliffe value. The proposed method is useful for studying hydrological processes of watershed associated with topography uncertainty and providing support for identifying proper water resources management strategy.

scholarly journals Weighted Visibility Classification and Seating Plan for the Aitken University Centre

2014 ◽  
Vol XL-2 ◽  
pp. 227-234
Author(s):  
T. Allison ◽  
D. Fraser ◽  
E. Stefanakis
Keyword(s):  
Web Application ◽  
Web Applications ◽  
Ice Surface ◽  
Price Levels ◽  
Digital Elevation ◽  
Information Products ◽  
Interactive Map ◽  
Elevation Model ◽  
The University

This paper describes the requirements for a weighted visibility classification of seats in the University of New Brunswick’s (UNB) Aitken University Centre (AUC). Price levels for seats are typically set for sections of seats based on promoter preferences. In a visibility classification, the digital elevation model (DEM) is created for the AUC and includes possible view obstructions. The view obstructions taken into account for this design were the penalty boxes, player bencher, and the rink boards. There were no other major obstructions in the AUC. The visibility calculations compute the number of visible pixels of the rink surface for each seat. It is expected that seats with a higher number of visible pixels will also have better visibility. The number of viewable pixels is weighted by distance to the center of ice surface to account for the preference of seats that are closer to the rink surface. This paper outlines the collection of data, weighted visibility classification method, and the development of information products. There are two main objectives of this weighted visibility classification and seating plan: (a) to demonstrate that a weighted visibility classification is a viable method to classify seats, and that this methodology could be used to set price levels for a venue and (b) create online web applications to suit the functionality for users and venue administrators. The user web application allows the user to pan, zoom and perform limited searches in the interactive map.

scholarly journals Flood mapping in small ungauged basins: a comparison of different approaches for two case studies in Slovakia

2018 ◽  
Vol 50 (1) ◽  
pp. 379-392 ◽  
Author(s):  
Andrea Petroselli ◽  
Matej Vojtek ◽  
Jana Vojteková
Keyword(s):  
Hydrologic Modeling ◽  
Hydraulic Modeling ◽  
Flood Mapping ◽  
Ungauged Basins ◽  
Dem Resolution ◽  
Digital Elevation ◽  
Design Hydrographs ◽  
Elevation Model ◽  
Event Based ◽  
Relief Area

Abstract Flood mapping is a crucial element of flood risk management. In small and ungauged basins, empirical and regionalization approaches are often adopted to estimate the design hydrographs that represent input data in hydraulic models. In this study, two basins were selected in Slovakia and different methodologies for flood mapping were tested highlighting the role of digital elevation model (DEM) resolution, hydrologic modeling and the hydraulic model. Two DEM resolutions (2 m and 20 m) were adopted. Two hydrologic approaches were employed: a regional formula for peak flow estimation and the EBA4SUB model. Two hydraulic approaches (HEC-RAS and FLO-2D) were selected. Different combinations of hydrologic and hydraulic modeling were tested, under different spatial resolutions. Regarding the DEM resolution, results showed its fundamental importance in the low relief area while its effect was secondary in the moderate relief area. Regarding the hydrologic modeling, results confirmed that it affects the results of the flood areas in the same way independently of DEM resolution and that when using event-based models, the hydrograph shape determination is fundamental. Regarding the hydraulic modeling, this was the step where major differences in the flood area estimation were found.

scholarly journals Reducing scale dependence in TOPMODEL using a dimensionless topographic index

2009 ◽  
Vol 13 (12) ◽  
pp. 2399-2412 ◽  
Author(s):  
A. Ducharne
Keyword(s):  
Cell Size ◽  
Scale Dependence ◽  
Contour Length ◽  
Topographic Index ◽  
Dem Resolution ◽  
Unit System ◽  
Topographic Slope ◽  
Digital Elevation ◽  
Numerical Effect ◽  
Elevation Model

Abstract. This paper stems from the fact that the topographic index used in TOPMODEL is not dimensionless. In each pixel i in a catchment, it is defined as xi=ln(ai/Si), where ai is the specific contributing area per unit contour length and Si is the topographic slope. In the SI unit system, ai/Si is in meters, and the unit of xi is problematic. We propose a simple solution in the widespread cases where the topographic index is computed from a regular raster digital elevation model (DEM). The pixel length C being constant, we can define a dimensionless topographic index yi=xi-lnC. Reformulating TOPMODEL equations to use yi instead of xi helps giving the units of all their terms and emphasizes the scale dependence of these equations via the explicit use of C outside from the topographic index, in what can be defined as the transmissivity at saturation per unit contour length T0/C. The term lnC defines the numerical effect of DEM resolution, which contributes to shift the spatial mean x of the classical topographic index when the DEM cell size C varies. A key result is that both the spatial mean y of the dimensionless index and T0/C are much more stable with respect to DEM resolution than their counterparts x and T0 in the classical framework. This shows the importance of the numerical effect in the dependence of the classical topographic index to DEM resolution, and reduces the need to recalibrate TOPMODEL when changing DEM resolution.

scholarly journals DEM Resolution Impact on the Estimation of the Physical Characteristics of Watersheds by Using SWAT

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Waranyu Buakhao ◽  
Anongrit Kangrang
Keyword(s):  
Assessment Tool ◽  
Swat Model ◽  
Large Area ◽  
Mountain Area ◽  
Watershed Characteristics ◽  
Watershed Area ◽  
Dem Resolution ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Impact

A digital elevation model (DEM) is an important spatial input for automatic extraction of topographic parameters for the soil and water assessment tool (SWAT). The objective of this study was to investigate the impact of DEM resolution (from 5 to 90 m) on the delineation process of a SWAT model with two types of watershed characteristics (flat area and mountain area) and three sizes of watershed area (about 20,000, 200,000, and 1,500,000 hectares). The results showed that the total lengths of the streamline, main channel slope, watershed area, and area slope were significantly different when using the DEM datasets to delineate. Delineation using the SRTM DEM (90 m), ASTER DEM (30 m), and LDD DEM (5 m) for all watershed characteristics showed that the watershed sizes and shapes obtained were only slightly different, whereas the area slopes obtained were significantly different. The total lengths of the generated streams increased when the resolution of the DEM used was higher. The stream slopes obtained using the small area sizes were insignificant, whereas the slopes obtained using the large area sizes were significantly different. This suggests that water resource model users should use the ASTER DEM as opposed to a finer resolution DEM for model input to save time for the model calibration and validation.

scholarly journals The solution to DEM resolution effects and parameter inconsistency by using scale-invariant TOPMODEL

2012 ◽  
Vol 43 (1-2) ◽  
pp. 146-155 ◽  
Author(s):  
Jing Xu ◽  
Liliang Ren ◽  
Fei Yuan ◽  
Xiaofan Liu
Keyword(s):  
Scale Effects ◽  
Scale Invariant ◽  
Topographic Index ◽  
Topographic Complexity ◽  
Dem Resolution ◽  
Coarse Resolution ◽  
Resolution Factor ◽  
Digital Elevation ◽  
Fractal Parameters ◽  
Elevation Model

The parameter calibration of TOPMODEL is influenced by digital elevation model (DEM) resolution because of the utilization of scale-dependent topographic index representing hydrologic similarity. The downscaled DEM from the coarse-resolution DEM and the resolution factor are applied to remove the DEM scale effects on the upslope area. Meanwhile, a fractal method is introduced as an approach to account for the effect of DEM resolution on slope. A significant improvement on the estimation of slope directly from the coarse-resolution data is made by applying fractal parameters that are computed from the standard deviation of elevation and the topographic complexity index in a 3 × 3 window of the DEM to account for local variability in the surface. The method to downscale the topographic index distribution is then coupled with the TOPMODEL to develop the scale-invariant TOPMODEL and is applied to perform streamflow simulation in the context of different DEM resolutions in the Zishui catchment. Results show that the calculated hydrograph based on the DEM data at 900 and 1,800 m resolution is consistent with that based on the DEM data at 100 m resolution when the same parameter set is used.

scholarly journals Explicitation of an important scale dependence in TOPMODEL using a dimensionless topographic index

2009 ◽  
Vol 6 (2) ◽  
pp. 1621-1649 ◽  
Author(s):  
A. Ducharne
Keyword(s):  
Cell Size ◽  
Scale Dependence ◽  
Contour Length ◽  
Dimensionless Quantity ◽  
Topographic Index ◽  
Dem Resolution ◽  
Unit System ◽  
Topographic Slope ◽  
Digital Elevation ◽  
Elevation Model

Abstract. This paper stems from the fact that the topographic index used in TOPMODEL is not dimensionless. In each pixel i in a catchment, it is defined as xi=ln (ai /Si), where ai is the specific contributing area per unit contour length and Si is the topographic slope. In the SI unit system, ai /Si is in meters, and the unit of xi is problematic. Even if all the equations in TOPMODEL are homogeneous, it is confusing to use the logarithm of a non-dimensionless quantity as an index, and we propose a simple solution to this issue in the nowadays widespread cases where the topographic index is computed from a regular raster digital elevation model (DEM). The pixel length C being constant, we can define a dimensionless topographic index yi=xi−ln C. Reformulating TOPMODEL's equations to use yi instead of xi helps giving the units of all the terms in TOPMODEL's equations. Another advantage is to raise awareness about the scale dependence of these equations via the explicit use of the DEM cell size C outside from the topographic index, in what what can be defined as the transmissivity at saturation per unit contour length T0/C. We eventually demonstrate, based on various examples from the literature, that both T0/C and the spatial mean y of the proposed dimensionless topographic index are very stable with respect to DEM resolution. This markedly reduces the recalibration necessity when changing DEM resolution, thus offering an efficient rescaling framework.

scholarly journals Impact of Resolution and Source of Digital Elevation Model on Topological Attributes and Simulated Runoff by SWAT Model

2021 ◽  
Author(s):  
Farinaz Gholami ◽  
Alireza Nemati ◽  
Yue Li ◽  
Yang Hong ◽  
Junlong Zhang
Keyword(s):  
Digital Elevation Model ◽  
Assessment Tool ◽  
Swat Model ◽  
Computation Time ◽  
Low Resolution ◽  
Dem Resolution ◽  
Digital Elevation ◽  
Hydrologic Response Units ◽  
Elevation Model ◽  
The Impact

The Digital Elevation Model (DEM) of a watershed is one of the most important inputs in most hydrological analyses and plays a key role in the accurate prediction of various hydrological processes. Comprehensive knowledge of the impact of different DEM sources on the performance of a model is essential before utilizing the model. In this study, we evaluated the influence of TOPO1:25000, ASTER, and SRTM DEMs, as input, on the performance of the Soil and Water Assessment Tool (SWAT) model for the prediction of surface runoff. We also investigated the effect of the resolution of the studied DEM sources on the accuracy of the SWAT model in the estimation of runoff. The second objective of this study was to identify the most influential and the least impactful input parameters on the performance of the SWAT model. We studied the Zarrineh River watershed in Iran as a case study to compare the effect of the aforementioned DEM types and DEM resolution on the output of the SWAT model. The outcomes of the study demonstrated that influential parameters on predicted runoff as well as a few watershed parameters, such as reach lengths, reach slopes, number of sub-basins, and the number of hydrologic response units (HRU), differs noticeably when the DEM source and resolution changes. It was also observed that simulated results over-predict the runoff during low precipitation periods and under-predict the runoff during high precipitation months, and the accuracy of the simulated results decreases by reducing the DEM resolution. The results showed that the SWAT model had the best performance when the TOPO1:25000 DEM was used as the input source. Low-resolution DEMs are available to a wider range of researchers. The outcomes of the current study can be employed to estimate the impact of low-resolution input data on the simulated result as well as substantially reduce the computation time by decreasing the input DEMresolution with only a minor reduction of accuracy.

Sign in / Sign up

Export Citation Format

Share Document