Oehler, Till, Bakti, Hendra, Lubis, Rachmat Fajar, Purwoarminta, Ananta, Delinom, Robert and Moosdorf, Nils (2018) Origin and volume of fresh submarine groundwater discharge from a volcanic island (Lombok, Indonesia). [Talk] In: EGU General Assembly. , April 2018, Vienna .

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Abstract

Fresh submarine groundwater discharge (FSGD) from tropical volcanic islands might be high due to high aquifer
permeability, steep slopes and high precipitation rates. In eastern Lombok (Indonesia) FSGD is captured in
offshore wells and used as a water resource for the local population. In western Lombok several undeveloped
submarine springs were identified in a coral reef, which provide a potential water resource for the local population.
The source of FSGD in this area was investigated using stable isotopes of water. Discharge rates were estimated
using multiple methods including offshore Radon time series stations, a salinity mass balance model and a point
source model. Parameters used for discharge estimates were evaluated using sensitivity analyses, and discharge
estimates were further constrained using Monte Carlo Simulations. The discharge rates were then compared with
recharge estimates based on precipitation and evapotranspiration rates in the catchment area.
The results indicate rapid recharge due to high permeability of volcanic soils and low urbanization in the
catchment area (little sealed areas). Recharge and discharge estimates agree fairly well, while the volume under
study in general has the largest influence on volumetric discharge estimates. In terms of volumetric discharge the
submarine springs in western Lombok provide a potential further water resource, as they are located in shallow
waters and are easily accessible, while the brackish nature of the discharging water inhibits its use as drinking
water resource.

Document Type: Conference or Workshop Item (Talk)
Research affiliation: Biogeochemistry and Geology > Submarine Groundwater Discharge
Affiliations > Not ZMT
Date Deposited: 01 Sep 2020 12:56
Last Modified: 01 Oct 2020 13:01
URI: http://cris.leibniz-zmt.de/id/eprint/4125

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