No abstract

This study developed a model to identify the percent of building density (PBD) of DKI Jakarta Province in each pixel of Landsat 8 imageries through a multi-index approach. DKI Jakarta province was selected as the location of the study because of its urban environment characteristics.  The model was constructed using several predictor variables i.e.  Normalized Difference Built-up Index (NDBI), Soil-adjusted Vegetation Index (SAVI), Normalized Difference Water Index (NDWI), and surface temperature from thermal infrared sensor (TIRS). The calculation of training sample data was generated from high-resolution imagery and was correlated to the predictor variables using multiple linear regression (MLR) analysis. The R values of predictor variables are significantly correlated. The result of MLR analysis shows that the predictor variables simultaneously have correlation and similar pattern to the PBD based on high-resolution imageries. The Adjusted R Square value is 0,734, indicates that all four variables influences predicting the PBD by 73%.

A meteorological drought refers to reduced rainfall conditions and is a great challenge to food security. Information of a meteorological drought in advance is important for taking actions in anticipation of its effects, but this can be difficult for areas with limited or sparse ground observation data available. In this study, a meteorological drought indicator was approached by applying the Standardized Precipitation Index (SPI) to satellite-based precipitation products from multiple sources. The SPI based meteorological drought analysis was then applied to Java Island, in particular to the largest rice-producing districts of Indonesia. A comparison with ground observation data showed that the satellite products accurately described meteorological drought events in Java both spatially and temporally. Meteorological droughts of the eight largest rice-producing districts in Java were modulated by the natural variations in El Niño and a positive-phase Indian Ocean Dipole (IOD). The drought severity was found to be dependent on the intensity of El Niño and a positive-phase IOD that occurs simultaneously, while the duration seems to be modulated more by the positive-phase IOD. The results demonstrate the potential applicability of satellite-based precipitation monitoring to predicting meteorological drought conditions several months in advance and preparing for their effects.

The self-supply of groundwater at the household level, and especially in densely populated areas, is vulnerable to fecal contamination. The aim of this study was to assess the level of fecal contamination in groundwater of three urban villages in Bekasi City that depend greatly on groundwater: Jatiluhur, Sumur Batu, and Jatirangga. Water samples were taken from 255 households with various types of water sources in the rainy season from February-March 2020. Escherichia coli (E. coli) concentration was quantified with Colilert-18 using IDEXX Quanti-Tray/2000 based on Most Probable Number (MPN) method. E. coli levels were beyond the WHO standard and found in 60% of the sources; 24% were above 100 MPN/100 mL. The presence of E. coli in groundwater indicated a requirement for further treatment prior to the point of consumption and an urgent need to replace the water supply infrastructure for improved water sources.

Abstract.A cascade-pond system consists of six ponds located at Universitas Indonesia Campus, Depok. Its catchment area is dominated by high density urban area with moderate to high imperviousness. Some of riparian buffers surrounds six ponds are also occupied by high imperviousness that may lead some ecohydrological problems i.e. water quality degradation, declining freshwater biodiversity and food web changes. The aim of this study is assessing the current state of cascadepond system health. The assessment of macroinvertebrate indices is based on SingScore that have been developed by Public Utilities Board of Singapore for macroinvertebrate biotic index. Impervious cover data is obtained from high-resolution imageries and processed using ArcGIS 10.5. Qualitative statistics methods, Chi-squared test describes the relationship of macroinvertebrate indices with catchment area imperviousness and aquatic buffer zone. The health assessment based on macroinvertebrates indices shows that the lower ponds are relatively healthier than the upper one. There is also any significant relationship between macroinvertebrate indices with impervious cover based on chi square test and cross tabulation analysis.

The Medical Geographic Information System (Medical GIS) application during the COVID-19 pandemic crisis has become influential in communicating disease surveillance for health practitioners and society. The Johns Hopkins University has extensively used a well-known Web-GIS dashboard to track the COVID-19 cases since January 22 and illustrates the location and number of confirmed COVID-19 cases. Unfortunately, the dashboard particularly for Indonesian cases is only represented by one point (dot map) placed on the centroid of the Indonesian archipelago. Further research can fill the gap in downscaling the geographical location data of COVID-19 cases to the cities or even the village level in Indonesia and communicating the susceptible zoning to society. We uplift the point COVID-19 cases data to susceptible zoning gathered from official COVID-19 government websites, process it using Geographic Information System analysis, and communicate it to society through a Web-GIS dashboard. Five datasets, i.e., population data, administrative boundary, Landsat 8 OLI satellite imagery, COVID-19 cases geographic location, transportation infrastructure, and crowded places location, are used to analyze the susceptible area. Due to different standard data sources from each province in Indonesia, we only present provinces in Java Island with complete COVID-19 cases data on villages-scale. The technical challenges and future improvement in developing the national dashboard of Web-GIS-based susceptibility dashboard are also discussed. The dashboard information would further add some essential information for society to explore their zone status in adapting to the "New Normal" using the SICOVID-19 dashboard from their computers or gadgets during the pandemic crisis.

In the city of Bekasi, a large proportion of the population uses groundwater and is at risk of Escherichia coli contamination. Water can remain contaminated by E. coli even after treatment, and it may be recontaminated through storage practices. This research aims to analyze the effect of boiling and the correlation of water storage practices to E. coli contamination in the drinking water of households in the villages of Jatiluhur, Sumur Batu, and Jatirangga. Among 54 randomly surveyed households, 98.1% boiled their water before drinking. The results show that 67% showed decreased E. coli after boiling. Boiled water with a low risk of E. coli made up 64.8% of the samples, a medium risk made up 25.9%, a high risk made up 7.4%, and a very high risk made up 1.9%. Observation of water storage practices showed that 51% of households store water in a jug after treatment, and 35.3% store it in a kettle or pot. Residents used a container equipped with a lid 94.1% of the time. The statistical analysis revealed no correlation between water storage practices and E. coli contamination in drinking water. Boiling water can be a fairly effective way to decrease E. coli contamination; however, other factors that can recontaminate water, such as storage hygiene and hand washing, require attention in future studies.

Previous studies state that improper landfill or waste management is one of the main causes of nitrite, nitrate, and heavy metal contamination in groundwater. In Bekasi, Indonesia, 70% of the population depends on groundwater for daily use, including the residents of Sumur Batu. The village of Sumur Batu is located adjacent to two landfills, namely, the Bantar Gebang landfill, which is the largest landfill in Indonesia, and the Sumur Batu landfill. This research analyzed the health risk of drinking groundwater that may have been contaminated by nitrite, nitrate, and heavy metals. Data processing was performed separately for different age groups: infants, children, and adults. The results showed that there is a risk of NO2 exposure in all age groups when groundwater is used as a source of drinking water in Sumur Batu. Because the region is directly bordered by a landfill area and the community is highly dependent on groundwater, as long as access to water services is not guaranteed, the quality of groundwater in this area needs to be monitored.