The management of groundwater quality is a critical issue in developing nations where sanitation and drinking water targets are commonly addressed by facilitating access to groundwater, which is then managed as a common-pool resource. We investigate the quality of the shallow unconfined groundwater in Dili's alluvial fan system, which 50% of Dili's rapidly growing population use for all their water requirements. Using the basic chemical and microbiological analyses that are locally available (sulfate, total hardness, fluoride, manganese, iron, ammonia, nitrite, nitrate, total coliform and E. coli) we show that the shallow wells commonly contain enhanced concentrations of dissolved solids and microbiological contaminants (total coliform and E. coli), relative to deeper wells. Cool, shallow wells are worse than warm equivalents. Elevated nitrate and nitrite pollution in the embassy district are tentatively attributed to affluence factors, such as lawn cultivation and water filtration equipment. Microbiological contamination, and associated manganese contamination of groundwater, mimic population patterns, but are concentrated in the finer grained sediments of the small fans and low-slope interdistributary areas. We suggest that rapid development and successful implementation of appropriate sanitation policy in Dili (and elsewhere) is required to address the problematic features of the shallow groundwater system. Success will be predicated on (1) the establishment of baseline data, and (2) development of a systems-thinking approach to holistic water resource management.
This study aims to apply a hydrogeological approaches and analysis of the 2021 flood event of Tasi-Tolu Lagoon to achieve four specific goals. Firstly, the study seeks to determine the natural characteristics of the lagoon, which include factors such as size, depth, water quality, and ecosystem composition. Secondly, the influence of precipitation on the water volume in the lagoon will be examined. This analysis involves assessing historical rainfall patterns in the region, as well as the amount and frequency of precipitation during the 2021 flood event. Thirdly, the hydrogeologic and geologic conditions of the lagoon will be evaluated. This involves examining factors such as the type and structure of the soil and bedrock, the presence of aquifers or other underground water sources, and the movement of water through the surrounding landscape. Finally, the study seeks to assess the risk of future flooding in Tasi-Tolu Lagoon, based on the insights gained from the previous analyses. Overall, this study's goal is to provide a comprehensive understanding of the hydrogeological factors that contribute to flooding in Tasi-Tolu Lagoon. This knowledge could be used to inform flood mitigation strategies or to improve our ability to predict and respond to future flooding events in the region.
The management of groundwater quality is a critical issue in developing nations where sanitation and drinking-water targets are commonly addressed by facilitating access to groundwater, which is then managed as a common-pool resource. We investigate the quality of the shallow unconfined groundwater in Dili's alluvial fan system, which 50% of Dili's rapidly growing population access for all their water requirements. Using the basic chemical and microbiological analyses that are locally available (sulfate, total hardness, fluoride, manganese, iron, ammonia, nitrite, nitrate, totalColiform and E. Coli.) we show that the shallow wells commonly contain enhanced concentrations of dissolved solids and microbiological contaminants (Total coliform and E. Coli.), relative to deeper wells. Cool, shallow wells fare worse than warm equivalents. Elevated nitrate and nitrite pollution in the embassy district are tentatively attributed to affluence factors, such as lawn cultivation and water filtration equipment. Microbiological contamination, and associated manganese contamination of groundwater, mimic population patterns but are concentrated in the finer grained sediments of the small fans and low slope interdistributory areas. We suggest that rapid development and successful implementation of appropriate sanitation policy in Dili (and elsewhere) is required to address the problematic features of the shallow groundwater system. Success will be predicated on 1) the establishment of baseline data, and 2) development of a systems-thinking approach to holistic water resource management. Any such program must engage with community leadership and water politics, and with the full, presently poorly understood, cohort of water-related service providers and NGOs operating in Timor-Leste.
Timor island has a tropical climate with relatively little rainfall and surface water is often not available throughout the year with groundwater relied on to fulfill daily domestic necessities. Geological reconnaissance mapping, hydrogeological investigation, and resistivity survey were undertaken in this study to systematically understand the hydrogeologic system (e.g., aquifer system, hydrostratigraphic units, groundwater flow direction) and its potentiality for water supply to human consumption in Alaua Kraik area, Baucau Municipality, Timor-Leste. Res2DInv, Dips 5.1, Surfer 16, Global Mapper 13, and Arc-GIS 10.6 software was used to create geological reconnaissance maps, resistivity interpretation profile lines, and a hydrostratigraphic model. Rainfall precipitation, rainfall intensity, maximum rate of runoff and infiltration data are also used to interpret the groundwater potential in the study area. Two rock units occur in the study area; permeable alluvial deposits which unconformable overlie impermeable interbedded red marl-chert and calcareous shale. Structurally the area comprises the Lacamutu anticline, thrust fault, left slip fault, and normal right slip fault. Resistivity lines indicate three (3) types of lithologies: alluvial deposit, an intercalated layer of red marl-chert, calcareous shale and wet calcareous shale. The alluvial deposit and red marl-chert layer intercalated with calcareous shale units are classified as a hydrostratigraphic unit of intergranular and localised aquifer systems with low productivity. The groundwater flows through the existing fractures of the shear joint and tends to flow towards the left slip fault plane zone from the North to South direction. Much of the rainwater in the study area is most likely intercepted, evaporated, and or transpiration as opposed to running off and infiltrating into How to cite this paper:
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