Optimization of reservoir operation for domestic water supply under climate change : a case study of the Buhisan watershed, Cebu city, Philippines | |
| Author | Oppus, Beatriz Nicolle Ablat |
| Call Number | AIT Thesis no.WM-25-03 |
| Subject(s) | Climatic changes--Philippines--Case studies Water-supply--Philippines--Case studies Hydrologic models |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Water Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | This study conducted a comprehensive assessment of reservoir operation optimization under the impacts of climate change in the Buhisan Watershed, located in Cebu City, Philippines. The research was structured with four key objectives: First, it analyzed historical and projected climate data to identify significant trends and patterns relevant to climate change. Second, it employed regionalization techniques, combining spatial proximity (based on geographical distance) and behavioral similarity (based on catchment attribute), to determine hydrological parameters for the ungauged watershed. Third, it utilized these calibrated parameters—such as CN2, GW_DELAY, GW_REVAP, SOL_AWC, ESCO, SOL_K, SOL_Z, and SOL_BD—to simulate the hydrological response of the Buhisan Watershed. Finally, it evaluated the reliability, resiliency, and vulnerability of the dam’s outflow under climate change and proposed strategies to optimize reservoir operations.To project future climate conditions, the study integrated three GCMs: ACCESS ESM1-5, IPSL-CM6A-LR, and MRI-ESM1-5. These models were used to project rainfall, maximum temperature, and Tmin across three future periods: the NF (2015 2040), FF (2041-2070), and FF (2071-2100). The projections were analyzed under two SSPs: SSP2-4.5 (moderate emissions) and SSP5-8.5 (high emissions). The results indicated a significant temperature rise, potentially reaching 3.80°C by the end of the century, alongside shifting rainfall patterns—the rainfall was elevated during rainy season and decreased during the dry season.The hydrological simulations revealed a forecasted to decrease in inflow to the Buhisan Dam by the end of the century, which could severely limit water supply. To address this, the study assessed the performance of the existing operational rule curve, which showed lower reliability under baseline demand. Consequently, the research proposed optimized reservoir operations, suggesting an optimal percentage combination of 20% (NF), 12% (MF), and 10% (FF) for both SSP scenarios. These optimizations resulted in improved reliability indices, with values of 0.77, 0.57, and 0.50 under SSP2-4.5 and 0.69, 0.50, and 0.52 under SSP5-8.5 for the three-time frames. |
| Year | 2025 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Shrestha, Sangam; |
| Examination Committee(s) | Shanmugam, Mohana Sundaram;Natthachet Tangdamrongsub; |
| Scholarship Donor(s) | DOST-SEI Foreign Graduate Scholarships, Philippines;Global Water and Sanitation Center (GWSC);AIT Scholarship; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2025 |