Ignasius Loyola Setyawan Purnama

Bio: Ignasius Loyola Setyawan Purnama is an academic researcher from Gadjah Mada University. The author has contributed to research in topics: Groundwater & Aquifer. The author has an hindex of 2, co-authored 14 publications receiving 43 citations.

Groundwater vulnerability study using SINTACS method in Banguntapan district, Bantul Regency

Abstract: As one of the districts in Bantul Regency which borders directly with the City of Yogyakarta, the District of Banguntapan has the potential to be an area affected by city development. This is what drives population growth in this district, so that the waste it generates also increases. The purpose of this study is to determine the level of groundwater vulnerability to pollution by using the SINTACS method and analyzing the dominant factors that influence it. Calculation and analysis results show that the variation of groundwater vulnerability index values in the study area ranged from 182.8 to 200.3, with 10 locations classified as high vulnerability and 2 locations classified as rather high vulnerability. Because it is located in a similar geological condition, namely the Aquifer Unit of Merapi Volcanic Fluvio Plain where most of the constituent material of this aquifer is sand and a little clay as inserts, the difference in groundwater vulnerability to pollution in the study area is only determined by the difference in groundwater depth.

Groundwater vulnerability assessment to pollution in Kasihan, Bantul Regency: A comparative method study (GOD, SINTACS and DRASTIC)

Abstract: Groundwater vulnerability to pollution refers to the ease with which pollutants reach groundwater, in other words indicating the level of ease of an area to experience pollution. At present, the theme is one of the themes that attracts many researchers because pollution is more frequent in an area. The purpose of this study is to assess groundwater vulnerability in the study area for pollution using the GOD method and conduct a study of 3 groundwater vulnerability assessments, to determine the most appropriate assessment to be applied in the study area. The method used to determine groundwater vulnerability to pollution is GOD, which uses three parameters to assess the vulnerability of groundwater, namely aquifer type, rock type above aquifer and groundwater level. Furthermore, the results of the vulnerability assessment using the GOD method are compared with the vulnerability assessment according to the SINTACS and DRASTIC methods that have been carried out before in this area. The results showed that the variation of groundwater vulnerability index values in the study area according to the GOD method was from 0.35 to 0.63. Locations that are classified as medium vulnerability are generally located in the limestone Sentolo Formation, while locations that are classified as high vulnerability class are located in the volcanic rock of Yogyakarta Formation. Noting the results of determining groundwater vulnerability from the three methods, it can be said that the three methods are suitable for assessing groundwater vulnerability in the study area. However, looking at the distribution pattern of the level of pollution, the DRASTIC method can provide more detailed results related to the level of vulnerability.

Pollution Load Capacity Analysis of BOD, COD, and TSS in Karang Mumus River, Samarinda

Abstract: The Rivers in Indonesia often accommodate pollution from all community activities. This happened due to a large number of people who use watersheds for living. One of those rivers is the Karang Mumus River in Samarinda City, East Kalimantan. This study aims to analyze the capacity of the Karang Mumus River pollution load in segments 2, 3 and 4. The analysis model used in this study was the QUAL2Kw and ArcGIS models. The former used to calculate the capacity of river pollution and the latter used to determine land use. The results of the QUAL2Kw Model analysis shown that the capacity of the BOD was exceeded in all segments, COD was exceeded in all segments except segment 3. The entire segment had an allocation of sectoral pollution load originated from domestic activities. This study concluded that the dominant land use of settlements was one of the main causes of this problem.

State of the Art and Recent Advancements in the Modelling of Land Subsidence Induced by Groundwater Withdrawal

Abstract: Land subsidence is probably one of the most evident environmental effects of groundwater pumping. Globally, freshwater demand is the leading cause of this phenomenon. Land subsidence induced by aquifer system drainage can reach total values of up to 14.5 m. The spatial extension of this phenomenon is usually extensive and is often difficult to define clearly. Aquifer compaction contributes to many socio-economic effects and high infrastructure-related damage costs. Currently, many methods are used to analyze aquifer compaction. These include the fundamental relationship between groundwater head and groundwater flow direction, water pressure and aquifer matrix compressibility. Such solutions enable satisfactory modelling results. However, further research is needed to allow more efficient modelling of aquifer compaction. Recently, satellite radar interferometry (InSAR) has contributed to significant progress in monitoring and determining the spatio-temporal land subsidence distributions worldwide. Therefore, implementation of this approach can pave the way to the development of more efficient aquifer compaction models. This paper presents (1) a comprehensive review of models used to predict land surface displacements caused by aquifer drainage, as well as (2) recent advances, and (3) a summary of InSAR implementation in recent years to support the aquifer compaction modelling process.

Delineating multiple salinization processes in a coastal plain aquifer, northern China: hydrochemical and isotopic evidence

Abstract: . Groundwater is an important water resource for agricultural irrigation and urban and industrial utilization in the coastal regions of northern China. In the past 5 decades, coastal groundwater salinization in the Yang–Dai river plain has become increasingly serious under the influence of anthropogenic activities and climatic change. It is pivotal for the scientific management of coastal water resources to accurately understand groundwater salinization processes and their causative factors. Hydrochemical (major ion and trace element) and stable isotopic ( δ18O and δ2H ) analysis of different water bodies (surface water, groundwater, geothermal water and seawater) were conducted to improve understanding of groundwater salinization processes in the plain's Quaternary aquifer. Saltwater intrusion due to intensive groundwater pumping is a major process, either by vertical infiltration along riverbeds which convey saline surface water inland, and/or direct subsurface lateral inflow. Trends in salinity with depth indicate that the former may be more important than previously assumed. The proportion of seawater in groundwater is estimated to have reached up to 13 % in shallow groundwater of a local well field. End-member mixing calculations also indicate that the geothermal water with high total dissolved solids (up to 10.6 g L −1 ) with depleted stable isotope compositions and elevated strontium concentrations ( > 10 mg L −1 ) also mixes locally with water in the overlying Quaternary aquifers. This is particularly evident in samples with elevated Sr ∕ Cl ratios ( > 0.005 mass ratio). Deterioration of groundwater quality by salinization is also clearly exacerbated by anthropogenic pollution. Nitrate contamination via intrusion of heavily polluted marine water is evident locally (e.g., in the Zaoyuan well field); however, more widespread nitrate contamination due to other local sources such as fertilizers and/or domestic wastewater is evident on the basis of NO3 ∕ Cl ratios. This study provides an example of how multiple geochemical indicators can delineate different salinization processes and guide future water management practices in a densely populated water-stressed coastal region.

The characteristics and causes of increasingly severe saltwater intrusion in Pearl River Estuary

Abstract: Under the influences of both anthropogenic activities and natural forces, saltwater intrusion has been a main issue in the Pearl River Estuary (PRE), China, in recent decades. Using long-term observation data for river channel bathymetry, hydrology, hydraulics, and meteorology, the causes and effects of the increasingly severe saltwater intrusion were investigated in this study. The worsening saltwater intrusion is characterized by an increase in salinity, prolonged and seasonally advanced duration with salinity exceeding the national standard, the extension of saltwater intrusion length and the highly stratified salinity, which can be attributed to uneven sand dredging, rising tides and changes of wind directions. Uneven sand dredging indirectly reduced the dilution capacity on the saltwater and made it difficult to discharge the saltwater. Rising tides and northeasterly migration of wind can strengthen the tidal dynamics and push saltwater further upstream. This study aims to draw attention to the issues of saltwater intrusion and offer information for the sustainable utilization of water resources for the estuaries around the world.