scholarly journals Managing the Flood Waves from Hemrin Dam

2021 ◽  
Vol 27 (7) ◽  
pp. 42-52
Author(s):  
Hajir Majid Ghali ◽  
Riyadh Z. Azzubaidi
Keyword(s):  
Cross Sections ◽  
Design Flood ◽  
Digital Elevation ◽  
Full Capacity ◽  
High Flood ◽  
Diyala River ◽  
Elevation Model ◽  
Strategic Study ◽  
Drop Structure ◽  
Flood Waves

Diyala Governorate was exposed recently to high flood waves discharged from Hemrin Dam to Diyala River when the dam reached its full capacity. The recently recorded discharge capacity of Diyala River was reduced to just 750m3/s. This exposes cities and villages along the Diyala River to flood risk when discharging the flood waves, which may reach 3000 m3/s. It is important to manage, suggest, and design flood escapes to discharge the flood waves from Hemrin Dam away from Diyala River. This escape branches from Hemrin Lake towards Ashweicha Marsh. One dimensional hydraulic model was developed to simulate the flow within the escape by using HEC-RAS software. Eighty-two cross-sections were extracted from the digital elevation model for the escape and used as geometric data. Moreover, thirty cross-sections for the Diyala River were utilized from the Strategic Study for Water and Land Resources in Iraq. Since the escape passes through two regions of different geological formations, two roughness coefficients of 0.035and0.028were used. Two discharge cases were applied3000m3/s, which is the 500 years return period extreme hydrograph of Hemrin Dam, and 4000 m3/s, which is the design discharge of Hemrin Dam spillway. A spillway was proposed at the escape entrance with crest level 105m.a.m.s.l., followed by a drop structure with eighteen rectangular steps

scholarly journals Flood Management of Diyala River

2021 ◽  
Vol 27 (8) ◽  
pp. 32-42
Author(s):  
Hajir Majid Ghali ◽  
Riyadh Z. Azzubaidi
Keyword(s):  
Cross Sections ◽  
Flood Management ◽  
Flood Wave ◽  
One Dimensional ◽  
Geological Formation ◽  
Full Capacity ◽  
Flood Period ◽  
High Flood ◽  
Diyala River ◽  
Drop Structure

Diyala Governorate was recently exposed to high flood waves discharged from Hemrin Dam. Since the dam was at its full capacity during the flood period, these waves were discharged to the Diyala River. Because of the reduction in Diyala River capacity to 750m3/s, the cities and villages on both sides of the river banks were inundated. Thus, the study's objective is to design a flood escape out of the Diyala River, to discharge the flood wave through it. The flood escape simulation was done by using HEC- RAS software. Two hundred twenty-three cross sections for the escape and 30 cross-sections of the Diyala River were used as geometric data. Depending on the geological formation that the escape passed through, two roughness coefficients of 0.035 and 0.028 were applied. An outflow downstream Hemrin Dam varies from 1100m3/s to 1800m3/s was applied as boundary condition upstream Diyala River. One dimensional hydraulic model was developed for the escape and the river, the results showed that aside weir could be constructed at the escape entrance with crest level 67m.a.m.s.l. and 800m width, followed by drop structure of four rectangular steps, this case provides safe discharge to Diyala River if flood wave of 1500m3/s released from Hemrin Dam.

scholarly journals Reconstructing Pre-Industrial Long Distance Roads in a Hilly Region in Germany, Based on Historical and Archaeological Data

2017 ◽  
Vol 1 (2) ◽  
pp. 642-660 ◽  
Author(s):  
Irmela Herzog
Keyword(s):  
Cross Sections ◽  
Lidar Data ◽  
Long Distance ◽  
Early 19Th Century ◽  
Digital Elevation ◽  
Hilly Region ◽  
Local Accuracy ◽  
Cost Paths ◽  
Elevation Model ◽  
The One

The aim of this contribution is on the one hand to map pre-industrial long distance roads located in a hilly region east of Cologne, Germany, as exactly as possible and on the other hand to assess the accuracy of least-cost approaches that are increasingly applied by archaeologists for prehistoric road reconstruction. Probably the earliest map covering the study area east of Cologne dates back to 1575. The map is distorted so that rectification is difficult. But it is possible to assess the local accuracy of the map and to transfer the approximate routes to a modern map manually. Most of the area covered by the 1575 map is also depicted on a set of more accurate maps created in the early 19th century and a somewhat later historical map set (ca. 1842 AD). The historical roads on these rectified historical maps close to the approximate roads were digitized and compared to the outcomes of least-cost analysis, specifically least-cost paths and accessibility maps. Based on these route reconstructions with limited accuracy, Lidar data is checked to identify remains of these roads. Several approaches for visualizing Lidar data are tested to identify appropriate methods for detecting sunken roads. Possible sunken roads detected on the Lidar images were validated by checking cross sections in the digital elevation model and in the field.

scholarly journals Morphology of Tigris River within Baghdad City

2012 ◽  
Vol 9 (5) ◽  
pp. 5671-5695
Author(s):  
A. A. Ali ◽  
N. A. Al-Ansari ◽  
S. Knutsson
Keyword(s):  
Cross Sections ◽  
Field Measurements ◽  
Water Levels ◽  
Huge Amount ◽  
One Dimensional ◽  
The Past ◽  
Tigris River ◽  
Critical Discharge ◽  
Diyala River ◽  
Flood Waves

Abstract. Changes in the morphology of the River Tigris within Baghdad City are very noticeable in recent years. The number of islands is increasing with time despite the fact that huge amount of sediments are trapped in reservoirs upstream Baghdad City. The debris of destroyed bridges in the wars of 1991 and 2003 had enhanced the development of these islands. As a consequence the ability of the river had been reduced to pass flood waves. This fact caused partial flooding of parts of Baghdad City. Cross sections of the River Tigris were surveyed in three occasions (1976, 1991 and 2008). The last survey conducted in 2008 by Ministry of Water Resources covered 49 km of the river from Al-Muthana Bridge to its confluence with Diyala River at 250 m intervals. The data was used to predict the maximum flood capacity for the river using one-dimensional hydraulic model for steady flow "HEC-RAS". Calibration was carried out for the model using field measurements for water levels along the last 15 km from its reach and the last 10 yr observations at Sarai Baghdad station. The average discharge of the river in Baghdad had been calculated for the past ten years. This value was introduced in the model. Then different scenarios were applied by increasing the discharge in order to find out the critical discharge that can cause inundation. The procedure continued to detect the areas that had been inundated and the water level was recorded. The model showed a significant reduction in the current river capacity in comparison with what the river had used to hold during floods of 1971 and 1988. The three surveys conducted on the same reach of the River Tigris indicated that the capacity of the river to pass water had been decreased. In addition the changes in the morphology of the river cross sections were very clear.

scholarly journals Influence of different sources of topographic data on flood mapping: urban area São Vendelino municipality, southern Brazil

RBRH ◽  
2020 ◽  
Vol 25 ◽  
Author(s):  
Fernando Campo Zambrano ◽  
Masato Kobiyama ◽  
Marco Alésio Figueiredo Pereira ◽  
Gean Paulo Michel ◽  
Fernando Mainardi Fan
Keyword(s):  
Cross Sections ◽  
Field Survey ◽  
Flood Mapping ◽  
Mean Velocity ◽  
Topographic Data ◽  
Digital Elevation ◽  
Wetted Area ◽  
Elevation Model ◽  
Best Fit ◽  
Different Sources

ABSTRACT Generally, the base for any flood mapping is the topography information whose resolution determines the map accuracy. Furthermore, river bathymetry in detail and the type of used model are also relevant. Therefore, the objective of the present study was to evaluate the influence of different sources of topographic data on the flood mapping by using the CAESAR-Lisflood model and three Digital Elevation Model (DEM) configurations, among which two were freely available, and the other was generated with field survey (topography and bathymetry). First, the resolution and precision of each DEM were evaluated, from the comparison of different cross-sections, besides the variation of the wetted area and absolute value of the relative error in mean velocity as a function of depth. Subsequently, after elaborating flood maps with each DEM, the results were compared in terms of flood area, mean flood width and flow depth. It is observed that the more accurate resolution, the smaller the flood area becomes. The flood map elaborated with the DEM through field survey had the best fit to the observed area. However the relation between the topographic resolutions and flow-depths was not clear in obtained results.

scholarly journals Technical Note: Water flow routing on irregular meshes

2006 ◽  
Vol 3 (6) ◽  
pp. 3675-3689 ◽  
Author(s):  
D. Bänninger
Keyword(s):  
Water Flow ◽  
Cross Section ◽  
Cross Sections ◽  
Technical Note ◽  
Hill Slope ◽  
Digital Elevation ◽  
Irregular Meshes ◽  
Elevation Model ◽  
Local Gradient ◽  
Flow Cross

Abstract. For spatial explicit hydrological modelling an algorithm was needed which works as cellular automata on irregular meshes. From literature it was found that usual algorithms applied for this purpose do not route the water flow correctly to its adjacent cells. In this study the hydraulic linking between mesh cells is done by calculating the flow cross section between the mesh cells. The flow cross sections are positioned in the centre of the mesh edges and are perpendicular to the local gradient of the digital elevation model. The presented algorithm is simple in its implementation and efficient in computation. It is shown that the proposed algorithm works correctly for different synthesised hill slope shapes.

scholarly journals Technical Note: Water flow routing on irregular meshes

2007 ◽  
Vol 11 (4) ◽  
pp. 1243-1247 ◽  
Author(s):  
D. Bänninger
Keyword(s):  
Water Flow ◽  
Cross Sections ◽  
Technical Note ◽  
Spatially Explicit ◽  
Hill Slope ◽  
Digital Elevation ◽  
Irregular Meshes ◽  
Elevation Model ◽  
Local Gradient ◽  
Flow Cross

Abstract. For spatially explicit hydrological modelling an algorithm was required that works as a cellular automata on irregular meshes. From literature it was found that the usual algorithms applied for this purpose do not route the water flow correctly between adjacent cells. In this study the hydraulic linking between mesh cells is done by calculating the flow cross section between the mesh cells. The flow cross sections are positioned in the centre of the mesh edges and are perpendicular to the local gradient of the digital elevation model. The presented algorithm is simple in its implementation and efficient in computation. It is shown that the proposed algorithm works correctly for different synthesised hill slope shapes.

Relationships between inherited crustal structures and seismicity in the western Alps inferred from 3D structural modeling

2010 ◽  
Vol 181 (6) ◽  
pp. 583-590 ◽  
Author(s):  
Christian Sue ◽  
Philippe Calcagno ◽  
Gabriel Courrioux ◽  
Pierre Tricart ◽  
Julien Frechet ◽  
...  
Keyword(s):  
Cross Sections ◽  
Seismic Activity ◽  
Structural Model ◽  
Sedimentary Cover ◽  
Field Method ◽  
Western Alps ◽  
Geological Body ◽  
Digital Elevation ◽  
Crustal Structures ◽  
Elevation Model

Abstract We developed a 3-D structural model of a key area in the southwestern Alps, at the boundary between the external and internal zones. Six geological bodies are analyzed: internal and external basements, Briançonnais and Piemontais zones (internal sedimentary cover nappes), exotic flyschs, and external sedimentary cover. 3D volumes of each geological body are modeled using the structural map of the area projected on the Digital Elevation Model (DEM) and 5 cross-sections. The global model is interpolated from the map, DEM, and cross sections, using the potential field method, and represented by a Voronoï diagram. The final 3D-model is used as a structural frame to plot the earthquakes of the GéoFrance3D database, allowing to precisely and quantitatively investigate the relationships between crustal structures and current seismic activity of the belt. The boundary between external and internal zones corresponds to the so-called Crustal Penninic Thrust (CPT), which is a former Oligocene major thrust. Our model establishes that this former thrust represents the western limit of the seismic activity along the Briançonnais seismic arc, currently undergoing extensional tectonics.

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>

scholarly journals Evaluation of Uncrewed Aircraft Systems’ Lidar Data Quality

2019 ◽  
Vol 8 (12) ◽  
pp. 532 ◽  
Author(s):  
Benjamin J. Babbel ◽  
Michael J. Olsen ◽  
Erzhuo Che ◽  
Ben A. Leshchinsky ◽  
Chase Simpson ◽  
...  
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Satellite System ◽  
Precision Data ◽  
The Road ◽  
Aircraft Systems ◽  
Accuracy And Precision ◽  
Digital Elevation ◽  
Elevation Model ◽  
Global Navigation Satellite

Uncrewed aircraft systems (UASs) with integrated light detection and ranging (lidar) technology are becoming an increasingly popular and efficient remote sensing method for mapping. Due to its quick deployment and comparatively inexpensive cost, uncrewed laser scanning (ULS) can be a desirable solution to conduct topographic surveys for areas sized on the order of square kilometers compared to the more prevalent and mature method of airborne laser scanning (ALS) used to map larger areas. This paper rigorously assesses the accuracy and quality of a ULS system with comparisons to terrestrial laser scanning (TLS) data, total station (TS) measurements, and Global Navigation Satellite System (GNSS) check points. Both the TLS and TS technologies are ideal for this assessment due to their high accuracy and precision. Data for this analysis were collected over a period of two days to map a landslide complex in Mulino, Oregon. Results show that the digital elevation model (DEM) produced from the ULS had overall vertical accuracies of approximately 6 and 13 cm at 95% confidence when compared to the TS cross-sections for the road surface only and road and vegetated surfaces, respectively. When compared to the TLS data, overall biases of −2.4, 1.1, and −2.7 cm were observed in X, Y, and Z with a 3D RMS difference of 8.8 cm. Additional qualitative and quantitative assessments discussed in this paper show that ULS can provide highly accurate topographic data, which can be used for a wide variety of applications. However, further research could improve the overall accuracy and efficiency of the cloud-to-cloud swath adjustment and calibration processes for georeferencing the ULS point cloud.

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