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Analysis of Groundwater Quality for Clean Water Supply in Pasaran Island, Bandar Lampung City, Indonesia
Full text linkPasaran is the only productive small island functioning as the anchovy and green clam production center in Bandar Lampung. Its water use has, however, increased since its designation as an economically fishery-based development area or minapolitan in 2012. This is due to the fact that groundwater resources in small island ecosystems surrounded by seawaters with a narrow diameter are easily affected by the insistence of seawater. Moreover, population pressure and land-use change are also feared to be affecting groundwater quality. Therefore, this research was conducted to analyze and evaluate groundwater resource quality in Pasaran Island using five wells on the entire island as sampling points selected based on census. The samples were tested for physical, chemical, and biological parameters in the laboratory and compared with water quality standards (Minister of Health’s Regulation No. 32/2007). The results showed relatively low water quality because the samples contained up to 3900 μS/cm salinity, 3771.9 mg/l chlorides, 31.7–141.52 mg/l nitrates, and 6.8–170 MPN/100ml total coliform which exceed the standards for drinking water. Meanwhile, wells 1, 4, and 5 were found to be safe for sanitation-hygiene purposes and well 1 was suitable for public baths even though they are not of drinking quality. This means the groundwater quality generally met Class II-water requirements for clean water supplies
Erosion Analysis in the Mrica Reservoir Catchment Area in Indonesia using the Soil Erosion Status Method
Full text linkThe reservoir catchment area (RCA) of Mrica in Banjarnegara district is a powerplant in Central Java with a capacity of 184.5 MW. Mrica Dam, also called the dam of Great Commander General Sudirman, has seen its functions gradually decrease due to sedimentation from massive erosion that has occurred in the upland regions. RCA Mrica, with the upland area in Wonosobo district, has an area of 93,546.4 hectares, consisting of six sub-watersheds, Lumajang, Serayu upstream, Begaluh, Serayu, Tulis and Merawu. In 2017, sedimentation in the dam reached 238,236,588.20 m3/year, resulting from an erosion rate of 524,948.33 tons/year. In light of this serious erosion problem in the Mrica RCA, this study aims to estimate the distribution of the erosion level, categorised as slight, moderate and severe, using the SES (soil erosion status) formula. SES was calculated by mapping the level of each influential aspect: aspect, drainage, land cover, slope and soil texture. The calculation used SRTM (Shuttle Radar Topography Mission) satellite imagery and 2017 Landsat TM7 images. The results show slight erosion (50 tons/ha/year) in 1,468.7 ha (1.6%); moderate erosion (50-100 tons/ha/yr) in 56,258.8 ha (60.1%); and severe erosion ( 100 tons/ha/year) in 35,818.9 ha (38.29%). Sampling in the field took into account the slope class of nine classes and was repeated three times, so the number of samples taken in the field was 27. From field visits to the 27 location points, there was conformity in the results of the sensing analysis is much more than 85%”. The results of the erosion calculation using the SES method showed severe erosion of 27.9% (26,137 ha); moderate erosion of 70.2% (65,679 ha); and slight erosion =of 1.8% (1,731 ha). Further erosion calculation using the SES method needs to be compared with calculation using other methods
Morphological Changes due to Anthropogenic Interferences in Gendol River Valley, Merapi Volcano
Full text linkThis research aims to identify the morphological changes in Gendol river, Merapi volcano. After the eruption 2010, Gendol river filled up by pyroclastic materials, then utilized as mining area. As the volcanic materials are abundance in Gendol river, sand mining activities are dominant, causing antrophogenic interferences that changes the morphology of Gendol valley. In this study, the morphological changes is measured by terrestrial survey, aerial mapping, and materials analysis through petrographic and granulometric analysis. Aerial mapping was conducted in February and August 2019 in order to identify the dynamic changes during 6 months observation. Vertical changes is found in the active mining zone, in western-side of research area, while horizontal changes was found in eastern-side. The comparison of widening and narrowing valley is 13:1 due to horizontal changes. Result of petrographic analysis showes that three different sampling locations originated from similar provenance, which is undissected arc provenance but may differ in period of sedimentation. Grain material found in research are categorized as suitable material for mining with the 0,733 mm grain size. However, the mining activities should be aware of material availability to minimize the riverbank failure
Using Hydrological Mapping to Evaluate the Effectiveness of the Bener Dam Development in Reducing Flood Risk in Purworejo Regency, Central Java
Full text linkThe Bogowonto Hulu sub-watershed has high flooding potential, especially during the rainy season. This flooding causes physical, social, and economic losses for the local community and so the Bener Dam was built to reduce the volume of flooding in the area. This research aims to find out the effectiveness of the Bener Dam in overcoming the problem of flooding around the Bogowonto Hulu sub-watershed. The effectiveness of dams can be analysed by comparing the volume of the dam reservoir with the peak discharge amount generated. The value of peak discharge can be obtained using remote-sensing data and mathematical calculations following the rational method. Using this method, the estimated peak discharge value obtained for the watershed was 302.3 m3/s while the value of dam capacity was only 210 m3/s, giving 92.3 m3/s of flooding potential. It is necessary to reduce the potential for flooding by building an IR reservoir in the catchment area, so that rainwater is accommodated rather than being immediately depleted, and to reduce concentration time
Comparison of Total Suspended Particulate (TSP) Measurement in Urban and Suburban Areas of Bali during Nyepi Day 2015
Full text linkNyepi or the Balinese Day of Silence (DOS) is a day when people celebrate every New Year according to the Balinese calendar (Saka). On that day, all resident activities were very restricted, with no outdoor activities. This event, which only lasted for 24 hours, is a unique period to conduct air quality measurements such as Total Suspended Particulate (TSP) for assessing the influence of human activities. This study only focuses on TSP monitoring before, during and after the DOS and its comparison with the meteorological data. TSP concentration measurements were conducted in 2 urban areas (Badung and Ubung) and a sub-urban area (Singaraja) from March 17 to March 25, 2015. The results show that TSP concentrations are negatively correlated with temperature and wind speed at each location. Hourly TSP concentrations during DOS are lower than the averaged TSP concentrations before and after DOS. During DOS, TSP concentrations decreased significantly in urban areas by 73-78% relative to regular days, which is likely due to drastically decreasing of human activities. In suburban areas, the decrease of TSP concentration was about 59%. These results show that human activities highly influence the air quality
Remote Sensing Imagery and GIS for Monitoring the Pyroclastic Material of Mount Sinabung
Full text linkThe purpose of this study was to determine the extent of changes in land cover around the Mount Sinabung area after the 2009-2019 eruption by monitoring through remote sensing imagery and GIS. The method used in this research is descriptive quantitative. The technique of data collection used document study techniques by collecting Landsat images are among the widely used satellite remote sensing data and their spectral, spatial and temporal resolution made them useful input for mapping and planning projects (Sadidy et al. 1981). Changes in land cover that occurred around the Mount Sinabung area were dominated by pyroclastic material due to eruption. In addition, changes in land cover also occur due to the abandonment of potential lands, such as local residents who work in the plantation sector are forced to leave that, so they eventually turn into shrubs. The direction of the dominant pyroclastic material slides was directed towards the east-south and southeast of Mount Sinabung, where the area was dominated by the plantation sector. The impact of the eruption of Mount Sinabung was directly and indirectly. The total land cover changes due to pyroclastic material in 2010 was an area of 26.27 Ha, in 2014 it was 475.82 Ha, 2017 was 1339.75 Ha, and 2019 was 1196.11 Ha
Analysis of Local Spatial Data Infrastructure to Support Volcanic Mudflow Mitigation along Putih River, Magelang Regency, Central Java Province, Indonesia
Full text linkOne of the most devastating disasters in Indonesia was the Mount Merapi eruption in 2010. After the eruption there still exists the secondary hazard of volcanic mudflow, which has caused damage and casualties. Volcanic mudflow is a mixture of pyroclastic material and rainwater, meaning that in the rainy season the area along rivers becomes a high volcanic mudflow hazard, including the area along Putih River in Magelang Regency, Central Java Province. The development of Spatial Data Infrastructure (SDI) plays an important role in disaster management, especially in disaster mitigation efforts. Building an SDI which shares information on spatial conditions in the area along the Putih River could save many lives and reduce the risk from volcanic mudflow. This research was conducted employing interview surveys, field surveys and secondary data collection at government institutions. The results of the analysis have provided a geoportal prototype as an information gateway for the mitigation of volcanic mudflow along the Putih River and the reduction of disaster risk both for the government and community
Understanding the Implementation of Small-Scale Water and Other Infrastructure Developments in Small Islands in Indonesia: A Rapid Survey in Bintan and Mandeh Islands
Full text linkAccess to clean water and electricity is one of the sustainable development agendas being addressed worldwide. However, people living on small islands scattered throughout Indonesia still face difficulties in accessing clean water and electricity. In an effort to overcome this problem, the Indonesian government and other donors are building small-scale clean-water infrastructure in a number of these small islands. Other infrastructure, such as electricity supply, has also been developed in a number of places. The infrastructure framework for these works is directed toward community-based management efforts. However, various problems have emerged after the construction of these facilities. Instead of achieving increased community participation in their management, the opposite occurs. This article investigates this situation using a rapid survey of communities in Bintan Island and Kapo-Kapo Island in the Mandeh Waters area, and finds that the development of small-scale infrastructure has a different impact on the two regions observed. An elaboration of various field findings is presented in detail in this article
The Role of Decision Making for Family Activities by Industrial Labour of Women Migrant Based on Their Migration Characteristics
Full text linkThe presence of women migrants in urban industrial workers proved that women's movement exists. This migration process not only indicates that women are actively involved in economic activity, but also influences the decision-making on important activities within the family and society. This study aims to determine the relationship between mobility patterns and its contribution to economic and decision-making in the family through the survey as research methods. The data were analysed by descriptive analysis, statistics approach, and correlation maps. For the independence test in the bivariate table, we used the chi square method, and to display the distribution of two variables simultaneously, a cross-tabulation was used. After that, to assess whether there is a relationship between the two variables, the table of independence was used. Our study shows that decision-making became an indicator of strengthening the role of women with a pattern of circular migration, which has a relationship on economic contribution. However, the behavior of women who perform the spatial migration in strengthening roles in families is not always relevant with the strengthening role of the economy. A strong role is only demonstrated by industrial migrant workers working on a circular migration pattern
The Compatibility of a GIS Map of Landslide-Prone Areas in Kendari City Southeast Sulawesi with Actual Site Conditions
Full text linkKendari is the capital of the Indonesian province of Southeast Sulawesi. It is located on mainly the karst hills region with high rainfall and there were numerous human activities on the karst hills. Many landslides have occurred in these areas. Natural and human factors may contribute to the landslide. The purpose of this study was to determine whether the present GIS map of landslide-prone areas was in agreement or compatible when compared to the actual site conditions in Kendari City. This research is mainly a regional survey. Data was collected through direct interview and observation at the sites. Data were analyzed quantitatively with percentages. The results showed that 87.4% of the area in Kendari City as shown in the map of landslide-prone distribution using GIS was included in the low risk or slightly vulnerable category. The category of landslide-prone areas was divided into; Very low risk, Low, Medium, High risk and Very high risk which represents the less vulnerable areas to the very vulnerable areas. The level of compatibility of landslide-prone maps in Kendari City, when compared with actual site conditions, reaches 75%. This shows that the map of the GIS spatial analysis can be used as a guide in mapping the level of landslide vulnerability in Kendari City. Landslide-prone map may be used as a guideline for engineers, designers, planners, and city officials in planning to reduce the risk of potential disaster