Aquifer vulnerability in the Coastal Northern Part of Lombok Island Indonesia

Nugraha, Gumilar Utamas; Bakti, Hendra; Lubis, Rachmat Fajar; Sudrajat, Yayat; Arisbaya, Ilham

doi:10.1007/s10668-021-01459-0

Cited by 4 publications

(3 citation statements)

References 57 publications

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“…The average error obtained in this inversion is 5.5%. The inverted resistivity models were then classified based on similar investigations in Lombok, especially related to pumice from the Samalas 1257 CE eruption (Hiden et al, 2017; Mutaqin et al, 2019; Nugraha et al, 2022). Drilling data also helped to interpret resistivity values for various sediment types, especially for distinguishing between sediment layers with pumiceous material and older sediment layers.…”

Section: Methodsmentioning

confidence: 99%

Coastal sedimentation and topographic changes in the Mataram Plain, Lombok (Indonesia) following the 1257 CE eruption of Samalas volcano

Malawani

Lavigne

Hadmoko

et al. 2023

Earth Surf Processes Landf

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The 1257 CE eruption of Samalas volcano, Indonesia, buried the entire island of Lombok beneath various thicknesses of pyroclastic material during this Volcanic Explosivity Index (VEI) 7 event. This study aims to reconstruct the paleo‐topography of western Lombok before the Samalas eruption in 1257 CE and analyse the sedimentation processes that led to its landscape evolution over the last 700 years. Stratigraphic data were collected from various surveys, such as outcrops, coring, drilling, hand auger and wells observation. Electrical resistivity tomography (ERT) measurements were performed to complement the stratigraphic data. A combination of stratigraphy, ERT and topographic data from various sources (topographic map, Digital Elevation Model Nasional [DEMNAS] and Real Time Kinematic [RTK] measurement) is employed to determine the depth of the paleo‐surface. Topographic modelling was performed by subtracting the delta‐DEM (DDEM) from the current‐DEM (CDEM). The result of this operation is a paleo‐DEM, which is used to reconstruct the paleo‐hydrographic features such as shoreline positions and river channels. Modelling results demonstrate that the relief has not been significantly modified, except in lowland areas, which is the sediment accumulation zone. River channels have experienced minor changes, except for the location of the river mouth and the degree of meandering. Significant changes occurred at the shoreline that has prograded by approximately 1.6 km during the last 700 years. A schematic model is built to illustrate the evolution processes of the study area, consisting of the pre‐eruption condition, the immediate post‐eruption condition and development of the current condition. This model further develops the previously proposed model with a higher resolution and simultaneously revises the estimated boundary of the pyroclastic density current (PDC) deposit from previous work.

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Section: Methodsmentioning

confidence: 99%

Coastal sedimentation and topographic changes in the Mataram Plain, Lombok (Indonesia) following the 1257 CE eruption of Samalas volcano

Malawani

Lavigne

Hadmoko

et al. 2023

Earth Surf Processes Landf

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“…In the northern part of the island, it can be expected that about 15% of the rainwater percolates into groundwater, which is vulnerable to pollution based on the local hydrogeology. 33 The aquifers most likely discharge their freshwater in the nearshore area below the sea as submarine springs. 34 River discharge into the coastal water in this area is located approximately 1 km toward the north and south of the submarine spring complex; however, these are nonperennial rivers.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…is the highest active volcano in Lombok, situated approximately 15 km south of the submarine spring complex where we conducted our study. In the northern part of the island, it can be expected that about 15% of the rainwater percolates into groundwater, which is vulnerable to pollution based on the local hydrogeology . The aquifers most likely discharge their freshwater in the nearshore area below the sea as submarine springs .…”

Section: Materials and Methodsmentioning

confidence: 99%

Terrestrial Nutrients and Dissolved Organic Matter Input to the Coral Reef Ecosystem via Submarine Springs

Adyasari

Waska

Daehnke³

et al. 2021

ACS EST Water

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Submarine groundwater discharge (SGD) transports terrestrial nutrients and dissolved organic matter (DOM) to the ocean. An elevated concentration of nutrients and DOM can act as stressors enhancing coral disease and mortality, but only a few studies address the impacts of groundwater-borne nutrients and DOM on coral reef ecosystems. This study quantifies and characterizes nutrients, nitrate (NO3 –) stable isotopes, and DOM molecular composition of coastal groundwater discharging to the reef ecosystem via submarine springs in Lombok, Indonesia. NO3 – isotopic values point to both natural (soil) and anthropogenic (wastewater and fertilizer) origins of nutrients in the coastal aquifer. Submarine springs are fed by different groundwater sources and deliver land-based NO3 –, dissolved silica, phosphate, and labile DOM to the reef water column. Terrestrial nutrients and DOM undergo rapid turnover in the reef water column due to biogeochemical processes and biological uptake. Meanwhile, reef and offshore water likely act as sources of more stable, reworked DOM formulas and its mineralization product, ammonium. We observed that submarine springs consistently deliver similar nutrient loadings, creating a long-term environmental threat to coral reef sustainability. This study emphasizes the importance of understanding coastal biogeochemistry and hydrological processes in sensitive tropical ecosystems, particularly those adjacent to modified land-use watersheds.

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