Risk Management of Reclamation Works Using CPM Method Based on Green Construction for The Patimban Port Project Phase 1-2

Abstract

Reclamation works employing the Cement Pipe Mixing (CPM) method in the Phase 1–2 Patimban Port Project involve environmental risks that may affect water quality, material efficiency, ecosystems, project cost, and schedule. This study aims to identify environmental risks, develop Green Construction-based risk treatments, and evaluate their implications for the Work Breakdown Structure (WBS), project schedule, cost, and implementation feasibility compared with the existing CPM approach. A mixed-methods approach based on ISO 31000:2018 was employed through stakeholder identification, identification of 30 environmental risks, development of a risk register, determination of mitigation measures, and formulation of a Green WBS, Green Schedule, and Green Cost. The analysis also compares the resulting Delta Cost and Cost of Risk. The findings indicate that the most significant risks occur during the Dredging and Pipe Mixing stages, with marine water quality representing the largest risk category at 33%. The integration of Green Construction introduces preventive controls, including silt curtains, real-time turbidity monitoring, leak detection, material loss control, emission monitoring, and waste management, without altering the fundamental CPM construction method. The main finding shows that project duration increases from 164 to 175 days, while cost increases from IDR 680.124 billion to IDR 684.304 billion. The resulting Delta Cost is IDR 4.18 billion, equivalent to 0.61% of the baseline cost, compared with an estimated Risk Treatment cost of IDR 8.065 billion. Thus, Green Construction is considered economically feasible on an indicative basis, as the additional mitigation cost is lower than the estimated risk-treatment consequence. The integrated framework also strengthens environmental risk control and supports the principles of SDGs 9, 12, 13, and 14.