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- Comparing Master Recession Curves using Seven Baseflow Recession Models
Authors: Bokiraiya Latuamury
Abstract: Baseflow recession analysis is an effective method for understanding catchment area releasing flow during dry season (without rainfall), thereby facilitating the management of water resources. Despite the availability of several theories on recession curves, there are limited studies on the comparison of different approaches. To overcome the limitation, several studies have reported the ability of master recession curves (MRC) modeling to combine automated methods for analyzing recession periods and curves shapes based on river flow data. Therefore, this study aimed to compare seven baseflow recession models for MRC characterization in small island watersheds. The Turkey test results showed that MRC visualization varied, particularly in terms of slope parameters and shapes. The seven recession models were grouped into two subsets based on their similarity. The first subsets consisted of Turbulent, Dupuit-Boussinesq aquifer storage, Depression-detention storage, Horton double exponential, Linear reservoir, and Exponential reservoir. Meanwhile, the second subset comprised Hyperbolic reservoir, Turbulent, Dupuit-Boussinesq aquifer storage, Depression-detention storage, Horton double exponential, and Linear reservoir. The findings also showed that the variability of MRC behavior depended on groundwater recharge, storage channel conditions, aquifer characteristics, and climate in the study area. These findings were also relevant to the development of MRC in other regions, such as hydrorecession tools, MRCPtool applications, sensitivity analysis-based Automatic parameter calibration of the VIC model for streamflow simulation over China, and spatial and temporal patterns in baseflow recession in the continental United States.
PubDate: 2024-08-08
DOI: 10.22146/ijg.89691
Issue No: Vol. 56, No. 2 (2024)
- Spatial Distribution Pattern of Covid-19 Cases and Their Characteristics
In DKI Jakarta and Surrounding Areas
Authors: Dwi Nowo Nowo Martono, Halvina Grasela Saiya
Abstract: The COVID-19 pandemic has significantly affected various countries worldwide, including Indonesia. This study specifically examines the spatial distribution pattern of COVID-19 cases among sub-districts in DKI Jakarta and its neighboring areas. The study investigates the impact of spatial characteristics such as building density, population density, road network connectivity, and accessibility, as well as infrastructure completeness. A spatial regression model was employed to analyze the influence and pattern of COVID-19 case distribution among sub-districts. Spatial modeling indicates that geographic location has an effect on the data, often referred to as the autocorrelation effect. Moran’s Index was used to test the relationship between district locations and the number and growth rate of cases.The study findings reveal a positive spatial autocorrelation in the growth rate pattern of COVID-19 cases among sub-districts and clusters in DKI Jakarta and its surrounding areas. The spatial regression model, specifically the Spatial Autoregressive Model (SAR), identifies road connectivity, number of health centers, building density, and population density as spatial variables that significantly influence the rate of COVID-19 cases.
PubDate: 2024-08-08
DOI: 10.22146/ijg.90542
Issue No: Vol. 56, No. 2 (2024)
- Flood Vulnerability Analysis Based on GIS and Remote Sensing at Silat Hulu
Authors: Ajun Purwanto, Dony Andrasmoro, Eviliyanto Eviliyanto
Abstract: A flood is a natural disaster that may happen anywhere and anytime. These disasters have become an annual cycle in Indonesia, and it is important to be swift in their mitigation and control. This study aims to determine the vulnerability of flooding in Silat Hulu and the extent of the area likely to be submerged. The method used was survey and secondary interpretation data. Data was from topographic maps, Sentinel 2A images, and 10 x 10 m resolution DEM images acquired on November 21, 2021, obtained from the ALOS PALSAR imagery. Data analysis using ArcGIS 10.8, using the weighted overlay spatial analysis tool. The results showed that the study location had three flood vulnerability classes: low, medium, and high. The locations with low vulnerability classes have an area of 2,921 ha, moderate have 32,683 ha, and high have 28,208 ha. Low flood vulnerability is spread to a small extent in Nangau Luan, Nangau Lungu, and Landau Badai villages. The level of vulnerability is mostly in Nangau, Nangau Lungu, and Landau Storm. The high level of vulnerability is mainly spread in the villages of Nangau Dangkan, Blimbing, Nangau Ngeri, and Nangau Lungu. GIS and remote sensing approaches are practical tools for flood-prone maps. Furthermore, GIS-based flood vulnerability mapping and remote sensing are valuable tools for estimating flood vulnerability areas.
PubDate: 2024-08-08
DOI: 10.22146/ijg.91114
Issue No: Vol. 56, No. 2 (2024)
- The Relationship of Microplastic Abundance, Flow Rate Discharge and
Drainage Profile in Bandar Lampung City, Lampung Province, Indonesia
Authors: Firdha Cahya Alam, Mutiara Fajar, Ester Patricia, Alisha Novelila, Nurul Mawaddah, Novi Kartika Sari
Abstract: The research on microplastics in urban drainage is becoming a concern. In the drainage of Bandar Lampung city, four different anthropogenic activities were investigated: road runoff, industrial activity, public place, and housing area. This study investigated the abundance, characteristics and distribution of microplastics (MPs) through drainage systems in dry weather. A total of sixteen drainage water samples were collected using grab sampling with a horizontal water sampler. Under microscope observation combined with a needle test, the average abundance of MPs was found 3.97±3.4 particles/L, with fibers as the dominant type of MPs. The order of MPs' abundance was industrial area > public area > transportation area > housing area. However, this number of MPs tends to be lower compared to other reported studies. The size of MPs mostly ranged from 500 - 1500 µm (36%). The color of MPs was amply diverse, with blue being in the dominant proportion (43%). Other studies also reported similar findings regarding the type and size range. Through Raman spectroscopy, the identification of polymer types indicated the presence of polyethylene terephthalate. From the correlation analysis, it was found that there was a positive correlation between the abundance of MPs and flow rate discharge, though with a low relationship (r=0.46). This result can be influenced by several factors such as the effects of multiple land use types and pollution sources. The significance of this research lies in its contribution to understanding the extent of microplastic pollution and its potential environmental impact on the Lampung water body.
PubDate: 2024-08-08
DOI: 10.22146/ijg.93040
Issue No: Vol. 56, No. 2 (2024)
- Three-Dimensional Participatory Mapping for Toponymical Name in
Nglanggeran Ancient Volcano of Yogyakarta
Authors: Fitria Nuraini Sekarsih, Ali Mustopa, Ari Cahyono, Kukuh Kukuh
Abstract: Place naming of a local area is closely related to geographic elements. Local names can also be used as a cultural identity and natural condition of a region. Nglanggeran Ancient Volcano (AV) area has local name elements highly influenced by those conditions. It is an interesting study material where a three-dimensional (3D) model can contribute as a medium to collect the place naming traces (toponym) in this area through participatory mapping. Participatory mapping, usually using 2D models in the form of sketches or maps, will be a separate story in interactive 3D media usage resulting from the photogrammetry process. It is expected that the media be able to show the geographical appearance of the Nglanggeran A.V area more clearly, such as geomorphology, geology, vegetation, hydrology, and even local culture, and contribute unexplored information. The results of participatory mapping in toponym collection are expected to be a medium that organizes the place naming of a local area into a complete database, along with the origin of the place names. It is also proposed that the results of participatory mapping through the 3D model be a means of preserving local culture in the Nglanggeran A.V area, making it more familiar to local residents and tourists.
PubDate: 2024-08-08
DOI: 10.22146/ijg.88278
Issue No: Vol. 56, No. 2 (2024)
- The Preliminary Sedimentation Pattern Study in West Borneo NPP Potential
Site
Authors: Euis E Alhakim, Theo A Ryanto, Heni Susiati, Hadi Suntoko
Abstract: Coastal environmet dynamics study is one of the NPP site feseability studies that need to be conducted to understand the potential external risk in an NPP development. The Pantai Gosong area was the preferred potential site for the NPP development and was located in the coastal area. Therefore, external factors such as abrasion or sedimentation would influence the NPP site. This research studied the sedimentation pattern of the Pantai Gosong coastal area based on the landform analysis. The results showed that the landform in the Pantai Gosong area was classified as a highly eroded hill, lowly eroded footplain, natural levee-back swamp, beach ridge, alluvial plain, and coastal alluvial plain. The sedimentation process in the northern coastal area of Pantai Gosong that has lowly eroded footplain landform was more intense than in the southern part. The analysis was well correlated with the estimated sediment thickness from the microtremor method analysis that showed that the northern coastal area has higher sediment deposits with 12.7 to 21.7 m of thickness than the southern coastal area with 3.2 to 12.6 m thickness. The northern footplain in the Pantai Gosong coastal area was expected to have higher sedimentation than the southern part continuously
PubDate: 2024-08-08
DOI: 10.22146/ijg.76686
Issue No: Vol. 56, No. 2 (2024)
- Dynamics of the Morphological Changes in the Progo River Due to Lahar
Transport from Merapi Volcano
Authors: Adib Prima Adhitama, Retnadi Heru Jatmiko, Estuning Tyas Wulan Mei, Junun Sartohadi
Abstract: The Merapi eruption in 2010 and 1975 caused lahar floods on the Progo River segment in Kulon Progo. This study aims to analyze the dynamics of river morphology changes that are affected by two lahar floods. Temporal images representing the two lahar flood events up to several years later were used to see river morphology changes. Temporal data from remote sensing and UAV is able to indicate the morphological change of river valleys in the study area. The analysis was carried out based on the parameters of river slope, riverbank morphology, and river curvature. The river slope is 0.74% which means the slope is flat. This condition gives a consequence of the river's meandering morphology. The morphology of the riverbank has the "U" shape, providing more surface area for river water to drain. The sinuosity ratio (SR) is dynamic during two lahar flood periods. In the 2010 lahar flood period, the SR pre-lahar flood was 1.92, increased significantly to 2.65 eight months post-lahar flood, and decreased significantly to 1.60 one year later. Lahar floods are the main factor causing these dynamics in this period. The annual SR for the next ten years is always changing but the fluctuations are more stable and tend to decrease. The SR's fluctuations in this period provide evidence that the river morphology is always changing even without major triggers. In the 1975 lahar flood period, the SR value was known from the PBB maps three years pre-events, five years post-events, and Google Earth images ten years post-events. The SR in this period fluctuated, and the meander became simpler at ten years post-events. The results of this paper provide evidence that spatial analysis with temporal images is more efficient and economical for studying river morphological dynamics.
PubDate: 2024-07-23
DOI: 10.22146/ijg.81788
Issue No: Vol. 56, No. 2 (2024)
- Enhancing Accuracy in Detection and Counting of Islands Using Object-Based
Image Analysis: A Case Study of Kepulauan Seribu, DKI Jakarta
Authors: Laode Muhammad Golok Jaya, Mutmainnah Muchtar, Sarimuddin Sarimuddin, Sitti Hairani Idrus
Abstract: Based on previous observations, a series of steps using digital image processing methods is proposed for the automatic detection and counting of islands to avoid inaccuracies from satellite imagery by leveraging morphological properties of object. The need for accurate spatial data regarding the number of islands in Indonesia is crucial for various developmental purposes. Many small islands known to have beautiful landscapes remain unaccounted for due to the vast territorial waters of the country, posing challenges to manual evaluation of the numbers and distributions. Remote sensing methods offer a viable solution for efficiently counting and inventorying islands. Therefore, this study aimed to detect islands in Kepulauan Seribu, located north of DKI Jakarta, through the thresholding-based segmentation process and count the total number using morphological information. The methodology applied was Object-Based Image Analysis (OBIA), including image gray-scaling, thresholding, morphological operations, connected component labeling, and region-based object counting. The results obtained showed 111 islands, compared to direct observation of image from which 104 were found, with detection accuracy of 93.27%. The discovery not only contributes valuable insights into the specific region but also serves as a basis for potentially applying digital image processing methods on a larger scale to recalculate the number of Indonesian islands. Such recalculations could play a crucial role in informing and guiding future developmental initiatives.
PubDate: 2024-07-23
DOI: 10.22146/ijg.82037
Issue No: Vol. 56, No. 2 (2024)
- Contribution of Commuters and Transit Activities on The Road Transport
Carbondioxides Emission in Surakarta
Authors: Widhi Himawan, Sajidan Sajidan, Sunarto Sunarto, Prabang Setyono, Natasha Nancy, Sovia Wijayanti
Abstract: Road transportation became a main contributor to the emissions of Surakarta City. The driving factor for these conditions is predicted to originate from massive commuting and transit activities. This research covered the administrative area of Surakarta City in July–August 2022. The aim of the research was to determine the impact of commuting and transit on carbon dioxide (CO2) emissions from Surakarta transportation and develop a spatial interpretation of the distribution of emissions. The emission estimation method uses a Tier 3 calculation approach using the Mobilev software. Estimation based on average daily traffic data for 24 hours as well as the character of the monitored path. The results of the study obtained an estimate of road transportation emissions for the City of Surakarta to reach 722795.3 tons of CO2 peryear. Commuter and transit activities contribute to 50.33% of total major road emissions or 133.77% of local vehicle emissions. Commuter and transit emissions in Surakarta City are dominated by private passenger cars (38.26%) and motorcycles (37.71%). Emission distribution shows a pattern of emission load that is greater on the city gate and transit lines than the central business district (CBD) area.
PubDate: 2024-07-23
DOI: 10.22146/ijg.83164
Issue No: Vol. 56, No. 2 (2024)
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