scholarly journals Genangan Banjir Pasang Pada Kawasan Pemukiman di Kecamatan Sayung, Kabupaten Demak – Provinsi Jawa Tengah

2015 ◽  
Vol 18 (1) ◽  
Author(s):  
Petrus Subardjo ◽  
Raden Ario
Keyword(s):  
Water Level ◽  
Digital Elevation Model ◽  
Model Verification ◽  
Sea Surface ◽  
Tidal Inundation ◽  
Central Java ◽  
Inundation Area ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Impact

Wilayah pedesaan di Kecamatan Sayung, Kabupaten Demak merupakan daerah pemukiman yang sering terjadi banjir pasang. Banjir pasang yang menggenangi daerah tersebut karena ketinggian daratan sejajar dan atau lebih rendah dengan muka air laut. Hal ini diduga disebabkan karena terjadinya pasang surut tinggi tertinggi atau HHWL (High Highest Water Level) di wilayah tersebut, sehingga diperlukan suatu tindakan untuk menanggulangi maupun mengurangi dampak yang ditimbukan oleh hal tersebut. Tujuan penelitian ini adalah untuk mengetahui kenaikan pasang surut tinggi tertinggi dari setiap tahunnya dari data nilai HHWL tertinggi setiap bulannya dalam satu tahun. Pengolahan data menggunakan metode admiralty dari tahun 2004-2013 dan tipe pasang surut di Kecamatan Sayung, Kabupaten Demak, serta pemetaan luas area genangan dan luas kawasan pemukiman pada area genangan banjir pasang di Kecamatan Sayung, Kabupaten Demak. Metode yang digunakan dalam penelitian ini adalah metode deskriptif yang bersifat eksploratif yaitu bertujuan untuk menggambarkan keadaan atau status fenomena. Penelitian ini dapat memberikan gambaran tentang situasi dan kondisi secara lokal dan hasilnya tidak dapat digeneralisasikan untuk waktu dan tempat yang berbeda. Selain itu perlu diketahui faktor-faktor penyebab banjir pasang di wilayah tersebut. Data utama yang dibutuhkan adalah data pasang surut, Digital Elevation Model (DEM), titik verifikasi banjir pasang pada kawasan pemukiman,peta tata guna lahan Kabupaten Demak tahun 2008 dan peta rupabumi tahun 2001. Berdasarkan hasil dari penelitian ini diketahui bahwa luas genangan banjir pasang yang terjadi di Kecamatan Sayung, Kabupaten Demak pada tahun 2013 adalah 1.938, 42 ha dan luas kawasan pemukiman pada area genangan sebesar 140,05 ha.Laju kenaikan Pasang surut tinggi tertinggi (HHWL) High highest Water Level dari tahun 2004 sampai tahun 2013 adalah sebesar 13.63 dan nilai HHWL tertinggi yang digunakan untuk membuat genangan banjir pasang dalam penelitian ini adalah bulan desember tahun 2013 sebesar 235.09 cm. Sedangkan Tipe pasang surut yang ada perairan Kecamatan Sayung, Kabupaten Demak adalah campuran condong harian tunggal.Kata kunci : Genangan, Banjir, Pasang, Kawasan Pemukiman, Kecamatan Sayung, Kabupaten DemakSubdistrict Sayung, Demak is the frequent flooding in residental areas. Flood tides inunndated areas which have a height of land area equal with the sea surface or lower than the sea surface. The areas thatoften Floods are Sriwulan Village, Purwosari Village, Sidogemah Village,Tugu Village, Surodadi Village, Gemulak Village, Bedono Village and Timbul Sloko Village. This happened because high highest water level at that areas, so that the action nasneccesary to overcome or decrease the impact. The purpose of this research was to determine the highest tidalrise in every year from the highest HHWL data values of each month in a year with admiralty data processing method from 2004-2013 as well as in the sub-type tidal Sayung, Demak and inundation mapping area and extensive residental areas to tidal inundation area in the district Sayung, Demak - Central Java Province. Method used in this research is descriptive explorative method that intoonded to describle the state or status of phenomenom. This research can provide an overvieuw of situation and conditions locally and the results may not generalizable to a different time and place. Besides that we need to known the causing factors of flooding in the region the main data we need required tidal flooding data, DEM (Digital Elevation Model), verification point in the settlement area, land use maps Demak in 2008 and 2001 topographical map. Based on the result of this research that widespread inundation flooding that occured in the district Sayung Demak in 2013 is 1.938,42 ha and extensive of residental areas to the inundation area of 140.05 ha. The rate of the highest tidal rise (HHWL) from 2004 to 2013 amounted 13.63 and the highest value of HHWL used to create tidal inundation in the study was desember 2013 amounted to 235.09 cm. While type of tidal waters that exist in the district Sayung, Demak is a mixture of single-learning daily.Keywords : Inundated, Flood Tide, Settlements, Subdistrict Of Sayung, Demak Regency

scholarly journals Impact of Spatial Resolution of Digital Elevation Model on Landslide Susceptibility Mapping: A case Study in Kullu Valley, Himalayas

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 360 ◽  
Author(s):  
Sansar Raj ◽  
Thimmaiah
Keyword(s):  
Digital Elevation Model ◽  
Spatial Resolution ◽  
Landslide Susceptibility ◽  
Susceptibility Mapping ◽  
Landslide Susceptibility Mapping ◽  
Mountainous Regions ◽  
Digital Elevation ◽  
Kullu Valley ◽  
Elevation Model ◽  
The Impact

Landslides are one of the most damaging geological hazards in mountainous regions such as the Himalayas. The Himalayan region is, tectonically, the most active region in the world that is highly vulnerable to landslides and associated hazards. Landslide susceptibility mapping (LSM) is a useful tool for understanding the probability of the spatial distribution of future landslide regions. In this research, the landslide inventory datasets were collected during the field study of the Kullu valley in July 2018, and 149 landslide locations were collected as global positioning system (GPS) points. The present study evaluates the LSM using three different spatial resolution of the digital elevation model (DEM) derived from three different sources. The data-driven traditional frequency ratio (FR) model was used for this study. The FR model was used for this research to assess the impact of the different spatial resolution of DEMs on the LSM. DEM data was derived from Advanced Land Observing Satellite-1 (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) ALOS-PALSAR for 12.5 m, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global for 30 m, and the Shuttle Radar Topography Mission (SRTM) for 90 m. As an input, we used eight landslide conditioning factors based on the study area and topographic features of the Kullu valley in the Himalayas. The ASTER-Global 30m DEM showed higher accuracy of 0.910 compared to 0.839 for 12.5 m and 0.824 for 90 m DEM resolution. This study shows that that 30 m resolution is better suited for LSM for the Kullu valley region in the Himalayas. The LSM can be used for mitigation and future planning for spatial planners and developmental authorities in the region.

scholarly journals Assessment of Changes in a Viewshed in the Western Carpathians Landscape as a Result of Reforestation

Land ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 430
Author(s):  
Michał Sobala ◽  
Urszula Myga-Piątek ◽  
Bartłomiej Szypuła
Keyword(s):  
Digital Elevation Model ◽  
Forest Succession ◽  
Western Carpathians ◽  
Surface Model ◽  
Digital Surface Model ◽  
Mountainous Areas ◽  
Viewshed Analysis ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Impact

A viewshed analysis is of great importance in mountainous areas characterized by high landscape values. The aim of this research was to determine the impact of reforestation occurring on former pasturelands on changes in the viewshed, and to quantify changes in the surface of glades. We combine a horizontal and a vertical approach to landscape analysis. The changes in non-forest areas and the viewshed from viewpoints located in glades were calculated using historical cartographic materials and a more recent Digital Elevation Model and Digital Surface Model. An analysis was conducted using a Visibility tool in ArcGIS. The non-forest areas decreased in the period 1848–2015. The viewshed in the majority of viewpoints also decreased in the period 1848–2015. In the majority of cases, the maximal viewsheds were calculated in 1879/1885 and 1933 (43.8% of the analyzed cases), whereas the minimal ones were calculated in 2015 (almost 57.5% of analyzed cases). Changes in the viewshed range from 0.2 to 23.5 km2 with half the cases analyzed being no more than 1.4 km2. The results indicate that forest succession on abandoned glades does not always cause a decline in the viewshed. Deforestation in neighboring areas may be another factor that has an influence on the decline.

Estimation of solar radiation from digital elevation model in area of rough topography

2016 ◽  
Vol 13 (5) ◽  
pp. 453-460 ◽  
Author(s):  
Lurwan Mahmoud Sabo ◽  
Norman Mariun ◽  
Hashim Hizam ◽  
Mohd Amran Mohd Radzi ◽  
Azmi Zakaria
Keyword(s):  
Solar Radiation ◽  
Digital Elevation Model ◽  
Spatial Data ◽  
Energy Planning ◽  
Solar Photovoltaic ◽  
Content Type ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Impact ◽  
Topographic Parameters

Purpose The purpose of this study is to evaluate the reliability of the technique for estimating solar radiation in areas of rough topography and to detect the source of error and means for improvement. Design/methodology/approach Spatial data of the study area in the form of digital elevation model (DEM) coupled with geographic information system (GIS) were used to estimate the monthly solar radiation at locations with rough topography. The generated data were compared with measured data collected from all the selected locations using NASA data. Findings The results show that the variation in topographic parameters has a strong influence on the amount of solar radiation received by two close locations. However, the method performed well for solar radiation estimated in the areas of rough topography. Research limitations/implications The proposed approach overestimates the monthly solar radiation as compared with NASA data due to the impact of topographic parameters accounted for by the model which are not accounted by conventional methods of measurements. This approach can be improved by incorporating the reflected component of radiation in the model used to estimate the solar radiation implemented in the GIS. Originality/value The approach of using GIS with DEM to estimate solar radiation enables to identify the spatial variability in solar radiation between two closest locations due to the influence of topographic parameters, and this will assist in proper energy planning and decision making for optimal areas of solar photovoltaic installation.

scholarly journals A Method for Dynamical Sub-Watershed Delimitating by No-Fill Digital Elevation Model and Defined Precipitation: A Case Study of Wuhan, China

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 486
Author(s):  
Hongping Zhang ◽  
Xinwen Cheng ◽  
Lei Jin ◽  
Dong Zhao ◽  
Tianjing Feng ◽  
...  
Keyword(s):  
Water Level ◽  
Digital Elevation Model ◽  
Flood Control ◽  
Return Periods ◽  
Wuhan City ◽  
Urban Flood ◽  
Digital Elevation ◽  
Elevation Model ◽  
Control Management

Watershed delimitation is very important in flood control management. The traditional sub-watersheds delimitated by a filling digital elevation model (DEM) may change the real sink area, such that it may not be the best choice in studies sensitive to sub-watershed storage. This paper proposes a dynamical watershed delimitation method using a no-fill DEM and precipitation. It considers a closed sink area containing cells that fully flow into a large special cell, which can flow out when its water level is “higher than outlet”. We took Wuhan City as a study area and defined the precipitation in return periods of 1, 5, 20, or 100 years to derive the sub-watersheds. It is found that, in the four delimitations, the ratio of isolated basic units which could not flow outside were 27%, 9%, 5%, and 1%, respectively, as the precipitation increased. The results show that the provided method satisfies the assumption that the sink area might overflow with increased precipitation. The sub-watershed delimitated by the proposed method has higher correlation with the distribution of waterlogging points than those delimitated according to the D8 algorithm. These findings indicate that the proposed method can derive reasonable sub-watershed delimitation and that it may be helpful in the practice of urban flood control management.

scholarly journals The impact of digital elevation model and land use spatial information on Hydrologic Simulation Program-FORTRAN – predicted stream flow and sediment uncertainty

2013 ◽  
Vol 16 (5) ◽  
pp. 989-1003 ◽  
Author(s):  
Huiliang Wang ◽  
Xuyong Li ◽  
Wenzan Li ◽  
Xinzhong Du
Keyword(s):  
Land Use ◽  
Digital Elevation Model ◽  
Spatial Resolution ◽  
Simulation Program ◽  
Hydrologic Simulation ◽  
Hspf Model ◽  
Sediment Loads ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Impact

The Hydrologic Simulation Program-FORTRAN (HSPF) model is widely used to develop management strategies for water resources. The spatial resolution of the input data used to parameterize the HSPF model may lead to uncertainty in model outputs. In this study, we evaluated the impact of the spatial resolution of the digital elevation model (DEM) and land use data on uncertainty in HSPF-predicted flow and sediment. The resolution of DEMs can affect stream length, watershed area, and average slope, while the resolution of land use data can influence the distribution of land use information. Results showed that DEMs and land use maps with finer resolutions generated higher flow volumes and sediment loads. There was a non-linear relationship between changes in resolution of the DEM and land use data and changes in the uncertainty of predicted flow and sediment loads. Relative error was used to describe model uncertainty and the probability density function was used to estimate these uncertainties. The best-fit distributions of uncertainty in modeled flow and sediment related to DEM and land use data resolution were the generalized Pareto distribution and the Johnson SB distribution, respectively. The results of this study provide useful information for better understanding and estimating uncertainties in the HSPF model.

scholarly journals Impact of interpolation techniques on the accuracy of large-scale digital elevation model

2020 ◽  
Vol 12 (1) ◽  
pp. 190-202 ◽  
Author(s):  
Maan Habib ◽  
Yazan Alzubi ◽  
Ahmad Malkawi ◽  
Mohammad Awwad
Keyword(s):  
Digital Elevation Model ◽  
Construction Projects ◽  
Large Scale ◽  
Digital Elevation ◽  
Distance Weighted ◽  
Elevation Data ◽  
Data Capturing ◽  
Dem Accuracy ◽  
Elevation Model ◽  
The Impact

AbstractThere is no doubt that the tremendous development of information technology was one of the driving factors behind the great growth of surveying and geodesy science. This has spawned modern geospatial techniques for data capturing, acquisition, and visualization tools. Digital elevation model (DEM) is the 3D depiction of continuous elevation data over the Earth’s surface that is produced through many procedures such as remote sensing, photogrammetry, and land surveying. DEMs are essential for various surveying and civil engineering applications to generate topographic maps for construction projects at a scale that varies from 1:500 to 1:2,000. GIS offers a powerful tool to create a DEM with high resolution from accurate land survey measurements using interpolation methods. The aim of this research is to investigate the impact of estimation techniques on generating a reliable and accurate DEM suitable for large-scale mapping. As a part of this study, the deterministic interpolation algorithms such as ANUDEM (Topo to Raster), inverse distance weighted (IDW), and triangulated irregular network (TIN) were tested using the ArcGIS desktop for elevation data obtained from real total station readings, with different landforms to show the effect of terrain roughness, data density, and interpolation process on DEM accuracy. Furthermore, comparison and validation of each interpolator were carried out through the cross-validation method and numerous graphical representations of the DEM. Finally, the results of the investigations showed that ANUDEM and TIN models are similar and significantly better than those attained from IDW.

scholarly journals Analisis Potensi Genangan Tsunami dan Penentuan Jalur Evakuasi Berbasis Sistem Informasi Geografis di Desa Daruba Pantai – Kabupaten Pulau Morotai

2021 ◽  
Vol 9 (1) ◽  
pp. 79-91
Author(s):  
Mohammad Ridwan Lessy ◽  
Nurhalis Wahiddin ◽  
Jefry Bemba ◽  
Marwis Aswan
Keyword(s):  
Digital Elevation Model ◽  
Active Faults ◽  
Safety Zone ◽  
Tsunami Inundation ◽  
Inundation Area ◽  
Digital Elevation ◽  
Study Results ◽  
Neighborhood Unit ◽  
Elevation Model ◽  
Evacuation Route

Tsunami is one of the catastrophic events that threatened coastal areas in Morotai Island Regency. This is partly because the location of the regency is among several active faults. Therefore, the study aims to analyze the tsunami inundation area and determine a tsunami evacuation route in Daruba Pantai Village, South Morotai District. This study begins with the preparation of a digital elevation model and is compiled with other related maps to produce the tsunami inundation area at the study site. The study results show that a tsunami can hit 176.65 ha, with the disastrous and dangerous category being 5.02% and 0.66%. Meanwhile, specifically for the Daruba Pantai Village area with an area of 60.59 ha, the disastrous and dangerous categories are 10.72% and 1.30%, and the safe category is 36.61% and secure 23.07%. Furthermore, the preparation of the evacuation route is based on the scenario that residents from each zone of both the Neighborhood Unit (RT) and Community Unit (RW) are directed to follow the evacuation path to move towards the temporary shelter point and towards the safety zone.

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