PERENCANAAN BENDUNG PEMBANGKIT LISTRIK TENAGA MIKRO HIDRO PADA SUNGAI LEMBAH KEMUNING, DI PONDOK PESANTREN AN-NUR LEMBAH KEMUNING, DESA SUKOANYAR, KECAMATAN PAKIS, KABUPATEN MALANG

Abstract

Abstract

The increasing demand for electricity encourages the utilization of new and renewable energy resources,
including hydropower through Micro Hydro Power Plants (MHP). The Lembah Kemuning River, located in
the An-Nur Islamic Boarding School area, Sukoanyar Village, Pakis District, Malang Regency, has a steep
topographic condition, a perennial river flow, and remnants of a former MHP water structure that may
be reused. This study focuses on the civil engineering planning of a diversion weir and supporting water
conveyance structures. Hydrological analysis uses ten years of annual maximum rainfall data from 2015
to 2024 obtained from the Abdulrachman Saleh Air Base rainfall station. Frequency analysis compares the
Gumbel and Log Pearson Type III distributions using Smirnov-Kolmogorov and Chi-Square tests. The
Gumbel distribution is selected because it satisfies both goodness-of-fit tests. Reliable discharge is
estimated using the F.J. Mock method and Weibull probability, while the design flood is calculated using
the Nakayasu Synthetic Unit Hydrograph method. The results indicate a Q80 reliable discharge of 0.34
m3/s and a 50-year design flood discharge of 34.50 m3/s. The proposed structure consists of a 0.40 m weir
crest above the riverbed, 0.85 m retaining walls, a total span of 5.30 m, a 2.50 m intake/sluiceway, and a
0.50 m headrace channel with a bed slope of 0.004 and a design velocity of 1.28 m/s. With an observed
natural head of approximately 2.8 m, a Vlugter-type stilling basin is proposed. Stability analysis gives a
factor of safety against overturning of 2.97 and against sliding of approximately 2.78, indicating that the
reviewed dimensions satisfy the adopted safety criteria. The study provides an initial engineering basis
for rehabilitation and development of the MHP civil structures, while further geotechnical and
electromechanical investigations remain necessary.
Keywords: micro hydropower, diversion weir, hydrology, F.J. Mock, Nakayasu, reliable discharge, weir stability, Lembah Kemuning River.