Development of sustainable groundwater management plan in Yogyakarta: Recharge and remediation techniques

Verma, Nishi (2018) Development of sustainable groundwater management plan in Yogyakarta: Recharge and remediation techniques. Honours thesis, Murdoch University.

Abstract

Since the 1970s, the Special Region of Yogyakarta in Indonesia has experienced systemic deterioration of groundwater, by way of physical depletion and chemical quality reduction. This is due to two main reasons – high groundwater abstraction rates and disconnect between water network and at least 90% of the population. In order to counteract these problems, this thesis looks at the development of a sustainable groundwater management strategy in Yogyakarta through groundwater recharge and remediation technologies. Similarities in site geology and hydrogeology imply that the province is similar in nature to Perth, Western Australia. As such, findings were also compared with technologies already being implemented in Perth.

The region of study had an area of 155.08 km2 and was observed to have a decline from the northern parts of the region to the south. Surface water flow travelled in a south-westerly direction while groundwater flow travelled in a straight, north-to-south direction. The presence of alluvial soils limited permeability and implied that both the Yogyakarta-Sleman and Wates aquifers were semi-permeable, likening it the confined Leederville and Yarragadee aquifers in Perth. A comparison of policy framework between the two cities showed that Yogyakarta’s lack of government enforcement and leniency with domestic residents led to significant over-abstraction of the aquifer.

In order to develop a sustainable strategy, two main target areas were focussed on – assessment of groundwater recharge and assessment of remediation technologies. Parameters such as water depth, hydraulic conductivity and chemical constituents were observed, along with a social survey detailing public perception of groundwater pollution, government assistance and acceptance of potential remediation techniques.

GIS image analysis of water depth and hydraulic conductivity suggested that the placement potential aquifer recharge sites would be best suited in the north-east part of the province, slightly outside the study area, to provide water for all. Geochemical modelling suggested that mixing surface water with groundwater would not lead in further pollution of the resource – as such two recharge schemes were proposed: an infiltration basin and an injection well with stormwater detention tank. High hydraulic conductivity in the study area favoured the instalment of injection basin using rainwater and stormwater capture to recharge the aquifers.

Loss of groundwater samples during transportation from Yogyakarta to Perth prohibited the analysis of treated groundwater via biosand filtration, activated carbon filtration, reverse osmosis and chlorination. However, in its stead, a qualitative analysis was carried out based on several key stakeholder values such as removal efficiency (as derived from literature) and cost of implementation. The use of a social survey identified the presence of different socio-economic classes, culminating in the selection of two technologies – reverse osmosis for those from more affluent backgrounds and a hybrid biosand filtration and chlorination system for drinking water for residents from lower socio-economic standing.

Summary of the findings found that aquifer recharge is a possible solution to Yogyakarta’s high abstraction rates due to increased pollution. While there is a need and want for remediation technologies, residents were hesitant to embrace their potential without government assistance. Therefore, it is suggested that a subsidy scheme be devised to encourage positive behavioural trends.

Future studies recommend that injection well trials are further developed in terms of sizing. Remediation techniques should be transported from Indonesia for a technical assessment on removal efficiency of contaminants.

Item Type:	Thesis (Honours)
Murdoch Affiliation(s):	School of Engineering and Information Technology
Supervisor(s):	Anda, Martin
URI:	http://researchrepository.murdoch.edu.au/id/eprint/44797

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