The Panji Jaya Village reservoir (embung) is planned as a water conservation
facility to meet the raw water needs of the community in Peninjauan Subdistrict,
Ogan Komering Ulu (OKU) Regency. Its development also supports the provision
of sustainable clean water access in rural settlements, in line with Sustainable
Development Goals (SDGs) 6 and 11. This study analyzes the hydrological
characteristics, dependable flow availability, and water balance of the reservoir to
evaluate the sustainability of raw water supply through 2035. Rainfall data from
the Lubuk Batang station (2021–2025) were tested for consistency using the Double
Mass Curve method (R² = 0.993), analyzed for frequency distribution using Log
Pearson Type III, and simulated using HEC-HMS 4.13 to obtain the Q90
dependable flow. Results show that the Q90 dependable flow ranged from 0.0005
to 0.0055 m³/second, peaking during the rainy season and declining significantly
during the dry season. A 15-day water balance simulation showed that the reservoir
storage experienced depletion in 5 of 24 periods in 2025, a condition projected to
worsen through 2035 as raw water demand increases. The effective storage
capacity of 19,240.97 m³ was found to be inadequate, indicating the need for
capacity review and more optimal operational management of the reservoir as part
of reliable water resources infrastructure planning.
Keywords: dependable flow, HEC-HMS, Log Pearson II, raw water demand,
reservoir (embung), water balance