EVALUASI SISTEM DRAINASE PADA KAWASAN JALAN MAWAR KOTA TENGGARONG DENGAN MENGGUNAKAN APLIKASI HEC-RAS --

ABSTRAK
Saluran drainase yang ada pada kawasan jalan Mawar Kota Tenggarong sering
mengalami banjir pada saat hujan intensitas besar sehingga air dapat menggenangi
kawasan sekitar. Tujuan dari penelitian ini adalah untuk melakukan evaluasi saluran
drainase pada kawasan jalan mawar, untuk mengetahui apakah kapasitas saluran
drainase dapat dialiri oleh debit limpasan banjir. Pada penelitian ini, untuk
mengetahui debit limpasan banjir pada kawasan jalan Mawar perlu dilakukan
dengan 2 metode, yaitu Metode Hidrograf Satuan Sintetik Nakayasu dan Metode
Rasional. Data yang diperlukan adalah data curah hujan harian, peta topografi, dan
peta tata guna lahan. Survey lapangan dilakukan untuk mengetahui arah aliran yang
ada pada kawasan jalan Mawar, dan dimensi saluran drainase eksisting juga perlu
dilakukan pengukuran untuk mengetahui berapa besar kapasitas saluran yang dapat
dialiri oleh debit banjir, serta melakukan pengukuran dengan menggunakan alat
Waterpass ukur untuk mengetahui kemiringan saluran drainase (Slope) pada
kawasan jalan mawar. Setelah dilakukan evaluasi didapat hasil distribusi frekunsi
parametrik Periode 2 tahun : 94.84 mm, Periode 5 tahun : 126.75 mm, periode 10
tahun : 147.88 mm, dan distribusi frekuensi non parametrik pada metode Smirnov-
Kolmogorof : 0.095 dan metode Chi-Square : 1 serta dimensi saluran yang dapat
dialiri oleh debit banjir rencana terbesar yaitu pada metode Rasional kala ulang 10
tahun adalah pada saluran 1 kanan ; B : 0.80 m, T : 1.70 m, h : 0.80 m, w : 0.50 m,
2 kanan ; B : 0.95 m, T : 2.96 m, h : 0.82 m, w : 0.60 m, 1 kiri ; B : 0.70 m, T : 3.02
m, h : 0.60 m, w : 0.60 m, 2 kiri ; B : 0.91 m, T : 2.96 m, h : 0.79 m, w : 0.60 m.
Kata Kunci: Saluran drainase, HEC-RAS, Metode HSS Nakayasu, Metode
Rasional
ABSTRACT
The drainage channels in the Mawar Street area of Kota Tenggarong often
experience flooding during heavy rain, causing water to inundate the surrounding
area. The purpose of this study is to evaluate the drainage channels in the Mawar
Street area to determine whether their capacity can accommodate the runoff from
floods. In this study, two methods are used to determine the flood runoff in the
Mawar Street area: the Nakayasu Synthetic Unit Hydrograph Method and the
Rational Method. Required data include daily rainfall data, topographic maps, and
land use maps. Field surveys are conducted to determine the flow direction in the
Mawar Street area, and measurements of the dimensions of existing drainage
channels are taken to determine their capacity to accommodate flood discharge.
Additionally, measurements using a waterpass survey instrument are carried out to
determine the slope of the drainage channels in the Mawar Street area. After
conducting the evaluation, the following results were obtained: parametric
frequency distribution for a 2-year return period: 94.84 mm, 5-year return period:
126.75 mm, 10-year return period: 147.88 mm, and non-parametric frequency
distribution using the Smirnov-Kolmogorov method: 0.095, and Chi-Square
method: 1. The dimensions of the drainage channels that can accommodate the
largest planned flood discharge are as follows, based on the Rational method with
a 10-year return period: right channel 1; base width (B): 0.80 m, top width (T):
1.70 m, height (h): 0.80 m, and flow width (w): 0.50 m, right channel 2; B: 0.95 m,
T: 2.96 m, h: 0.82 m, w: 0.60 m, left channel 1; B: 0.70 m, T: 3.02 m, h: 0.60 m, w:
0.60 m, left channel 2; B: 0.91 m, T: 2.96 m, h: 0.79 m, w: 0.60 m.
Keywords: Drainage channels, HEC-RAS, Nakayasu HSS Method, Rational
Method
ABSTRACT
The drainage channels in the Mawar Street area of Kota Tenggarong often
experience flooding during heavy rain, causing water to inundate the surrounding
area. The purpose of this study is to evaluate the drainage channels in the Mawar
Street area to determine whether their capacity can accommodate the runoff from
floods. In this study, two methods are used to determine the flood runoff in the
Mawar Street area: the Nakayasu Synthetic Unit Hydrograph Method and the
Rational Method. Required data include daily rainfall data, topographic maps, and
land use maps. Field surveys are conducted to determine the flow direction in the
Mawar Street area, and measurements of the dimensions of existing drainage
channels are taken to determine their capacity to accommodate flood discharge.
Additionally, measurements using a waterpass survey instrument are carried out to
determine the slope of the drainage channels in the Mawar Street area. After
conducting the evaluation, the following results were obtained: parametric
frequency distribution for a 2-year return period: 94.84 mm, 5-year return period:
126.75 mm, 10-year return period: 147.88 mm, and non-parametric frequency
distribution using the Smirnov-Kolmogorov method: 0.095, and Chi-Square
method: 1. The dimensions of the drainage channels that can accommodate the
largest planned flood discharge are as follows, based on the Rational method with
a 10-year return period: right channel 1; base width (B): 0.80 m, top width (T):
1.70 m, height (h): 0.80 m, and flow width (w): 0.50 m, right channel 2; B: 0.95 m,
T: 2.96 m, h: 0.82 m, w: 0.60 m, left channel 1; B: 0.70 m, T: 3.02 m, h: 0.60 m, w:
0.60 m, left channel 2; B: 0.91 m, T: 2.96 m, h: 0.79 m, w: 0.60 m.
Keywords: Drainage channels, HEC-RAS, Nakayasu HSS Method, Rational
Method