DRASTIC and SINTACS Method: A Groundwater Vulnerability Assessment Method Comparison Study in The Karangkobar Groundwater Basin, Central Java.
Muhammad Iman Luthfi (a*), Izza Hayyu Hanani (a**), Thomas Triadi Putranto (a***)
a) Geological Engineering Department, Diponegoro University, Semarang, Indonesia
Jalan Profesor H. Soedarto Sarjana Hukum, Tembalang, Kota Semarang, Jawa Tengah 50275
*imanluthfi003[at]gmail.com
**z.hanani24[at]gmail.com
***putranto[at]ft.undip.ac.id
Abstract
Increasing and expanding the function of land use due to human activities can lead to potential pollution of groundwater. As a method that has been tested and has a precise scoring system, this study tries to use and compare the SINTACS and DRASTIC Methods to conduct groundwater vulnerability assessments (GVA). This study aims to create and compare the models of intrinsic and specific GVA from the SINTACS and DRASTIC methods and find out the most reliable model to be applied to the Karangkobar Groundwater Basin. Intrinsic GVA is carried out with the SINTACS and DRASTIC methods using seven parameters that are almost the same but differ in detail of classification, weight, and rating. The specific GVA is carried out with the Nitrate Vulnerability Index (Modified-DRASTIC) and SINTACS Specific Vulnerability Index (Modified-SINTACS) which uses additional parameters in the form of Anthropogenic Impact (AI) and Potential Risk Associated with Land Use (LU). These additional parameters are representations of land conditions that are affected by nitrate pollutants (NO3-). All models were validated using the nitrate concentration within 34 observation points to determine the level of models suitability with nitrate groundwater pollution conditions in the study area. The four GVA models show almost the same results. In general, areas with a High-Very High vulnerability are found in agricultural areas composed of pyroclastic sediment aquifers, while Low-Intermediate vulnerability levels are found in protected forest areas composed of alluvium deposits and pyroclastic deposits aquifer. Statistical analysis shows that the GVA models which have the strongest correlation (r = 0,8) with nitrate is the Nitrate Vulnerability Index model, so this model is considered the most appropriate to be applied in the study area.
Keywords: Karangkobar Groundwater Basin, groundwater vulnerability assessment, DRASTIC, SINTACS, nitrate
Topic: Disaster Management and Environmental Issues