Assessing Urban Groundwater Resilience: Case Study of Jakarta's Water Utilities

Thesis Abstract

Urban groundwater resources in Jakarta are increasingly stressed by rapid urbanization, sea-level rise, extensive groundwater extraction, and climate-related variability, which undermine the resilience of municipal water utilities and threaten service continuity for millions of residents. This study addresses the gap in integrated assessment of groundwater resilience within highly urbanized tropical megacities, focusing on Jakarta’s water utilities to inform adaptive management strategies. The aim is to quantify groundwater resilience and identify the drivers of vulnerability and pathways for adaptive response across operational, infrastructural, and governance dimensions. Specific objectives include (i) characterizing the hydrogeological baseline and spatial distribution of groundwater aquifers underlying Jakarta, (ii) evaluating the robustness of the groundwater supply system under representative hydroclimatic and anthropogenic stress scenarios, (iii) assessing institutional governance, policy instruments, and utility operational practices that influence resilience, (iv) estimating resilience indicators through a composite index integrating hydrogeochemical indicators, pumping patterns, and service reliability, and (v) proposing a suite of adaptation options with prioritized implementation pathways. Methodologically, the study adopts a mixed-methods design anchored in resilience theory and socio-hydrogeological systems thinking. The population comprises Jakarta’s urban groundwater users and the principal water utilities (PDAMs) serving Jakarta, with a sample of 60 pumping stations and 120 boreholes surveyed for hydrogeological and operational data, and 40 utility managers and engineers interviewed. Groundwater data (well yield, abstraction volumes, drawdown rates, aquifer recharge estimates, salinity and nitrate indicators) were collected over a 36-month period (2022–2024) from utility records, municipal groundwater databases, and field measurements using standardized logging protocols. Water quality data were augmented with 25 groundwater samples analyzed for major ions, stable isotopes, and trace metals. Instrument validity was enhanced through triangulation across records, field measurements, and stakeholder interviews. Reliability was ensured through test-retest of survey instruments (Cronbach’s alpha > 0. eight) and inter-rater checks for qualitative coding. Analytical techniques include (i) descriptive statistics and spatial interpolation (Ordinary Kriging) to map aquifer properties and pumping pressure zones; (ii) time-series analysis and regression modeling to relate groundwater yield and drawdown to rainfall indices, extraction volumes, and pumping efficiency; (iii) multivariate principal component analysis to construct a groundwater resilience index (GRI) integrating hydrological, infrastructural, and governance dimensions; (iv) scenario analysis using climate projections (RCP 4.5 and 8.5) and urban growth trajectories to test system robustness; (v) ANOVA and post-hoc tests to compare resilience across utility districts; (vi) thematic analysis of interview transcripts to elucidate governance barriers and enabling factors. The study applies the theoretical framework of resilience in socio-hydrogeological systems and incorporates the Pressure-State-Response model to interpret drivers and responses, supplemented by the Institutional Analysis and Development (IAD) framework to examine governance influences. Expected findings anticipate spatial heterogeneity in aquifer vulnerability with higher drawdown in peri-urban cores, coupled with elevated chlorides in saline intrusion-prone zones. The resilience index is expected to reveal moderate to high sensitivity to climatic variability and governance constraints, with strong correlations between pumping management practices and supply reliability. Thematic insights are likely to indicate that institutions with clear inter-agency coordination, transparent data sharing, and adaptive tariff mechanisms demonstrate enhanced resilience, while bureaucratic fragmentation and outdated infrastructure diminish adaptive capacity. The study aims to contribute to knowledge by integrating hydrogeological data with governance and operational metrics to create a replicable resilience assessment framework for urban groundwater systems, applicable to other tropical megacities facing similar pressures. It will provide Jakarta’s water utilities with evidence-based recommendations, including (i) prioritization of strengthened monitoring networks and real-time pumping optimization, (ii) targeted rehabilitation of aquifer recharge zones and well-field management, (iii) adaptive governance arrangements with boundary-spanning information flows and shared decision-making, (iv) demand-side management and pricing instruments calibrated to resilience objectives, and (v) scenario-driven contingency planning and investment prioritization. The main conclusion posits that urban groundwater resilience hinges on the integration of hydrogeological insight with adaptive governance and operational flexibility, necessitating institutional reforms, data transparency, and proactive infrastructure investments to maintain service reliability in the face of climatic and urban pressures.