Hendarmawan
Universitas Padjadjaran

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A Analysis of A Geologically Controlled Groundwater Basin: Major Ion Chemistry and Groundwater Flow Patterns on The Eastern Slope of Mount Gede Cianjur West Java Rina Rosmawati; T. Yan W. M. Iskandarsyah; Faishal Aziz; Wahyudi; Mochamad Nursiyam Barkah; Yudhi Listiawan; Hendarmawan
Jurnal Ilmiah Dinamika Rekayasa Vol. 22 No. 1 (2026): Jurnal Ilmiah Dinamika Rekayasa - Januari
Publisher : Engineering Faculty, UNSOED

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20884/1.jidr.2026.22.1.66

Abstract

Population growth is directly proportional to the increasing demand for water, while land-use changes into residential areas also affect the region’s water storage capacity. In Cianjur Regency, residents’ water needs are supplied by the Cianjur and Cibanteng sub-watersheds (Sub-DAS), most of which have undergone land conversion into settlements. This condition highlights the importance of studying groundwater flow systems to ensure the sustainability of water resources. Geologically, the area consists of old volcanic rocks and younger volcanic deposits, with permeability values ranging from 5.789×10⁻³ to 1.8752×10⁻⁷ cm/sec. Based on physical properties, groundwater shows different characteristics within a groundwater basin, EC and TDS values tend to increase downstream, indicating groundwater interaction. Chemically, the groundwater exhibits facies containing Mg-Ca, HCO₃ minerals, suggesting that the groundwater is in a transitional flow phase. The relatively high Mg/Ca ratio indicates that evaporation plays a significant role in controlling groundwater chemistry. The Ca-Mg or Ca/Mg phase forms due to dissolution processes from evaporation and prolonged interaction between water and older rocks. This phenomenon provides important insights into the dynamics of the groundwater flow system in Cianjur. The development of this groundwater flow is crucial for water resource planning and management in Cianjur Regency.
The Determination of Disaster-Prone Areas Based on a Multifactor Approach on the Manglayang Catastrophe Volcano Edifice, West Java, Indonesia: English Putu Ayu Andhira; Faishal Aziz; Muhammad Ghozi; Teuku Yan Waliana Muda Iskandarsyah; Johanes Hutabarat; Hendarmawan
Jurnal Ilmiah Dinamika Rekayasa Vol. 22 No. 2 (2026): Jurnal Ilmiah Dinamika Rekayasa - Juli
Publisher : Engineering Faculty, UNSOED

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20884/1.jidr.2026.22.2.145

Abstract

Manglayang is an extinct volcano in West Java characterized by a horseshoe-shaped amphitheater morphology, suggesting a past volcanic sector collapse that generated debris-avalanche deposits. This study aims to identify evidence of sector collapse, characterize debris-avalanche deposits, and delineate stable, susceptible, and hazardous landslide zones. The methodology combines Digital Elevation Model (DEM) data, Desaunettes landform classification, geological field observations, lithological analyses, and slope stability assessment. The results reveal a southeast-facing amphitheater interpreted as the main sector-collapse scar. Hummocky landforms are widely distributed between 2 – 6 km from volcnic cone and supported by debris-avalanche deposits characterized by volcanic breccias with jigsaw-crack structures and abundant large boulders. The integration of geomorphological, lithological, and geotechnical parameters indicates that steep hilly terrains represent the highest landslide susceptibility, whereas hummocky terrains are generally stable under present conditions. The proposed multifactor approach provides a comprehensive framework for reconstructing ancient volcanic collapse processes and improving disaster-prone area mapping in extinct volcanic terrains.