Pemodelan Banjir akibat Perubahan Tata Guna Laha di Daerah Aliran Sungai Ciliwung
Authors: Helena Abighail Sarah , Kridasantausa (alm.) Iwan , Farid Mohammad , Moe Idham Riyando 
Published: May 2022

Abstrak
Salah satu variabel berubah yang dapat memengaruhi karakteristik DAS dan hidrologi DAS tersebut adalah perubahan tata guna lahan. Pertumbuhan wilayah hulu, tengah, dan hilir DAS Ciliwung di berbagai sektor baik dari Bogor, Depok, hingga Jakarta sangat memengaruhi kondisi tata guna lahan DAS Ciliwung. Jakarta sebagai ibukota Negara Indonesia sekaligus wilayah hilir DAS Ciliwung terpapar pertumbuhan perekonomian yang paling siginifikan. Pertumbuhan ekonomi tersebut menjadi daya tarik urban dan investor sehingga terjadi peningkatan kebutuhan infrastruktur seperti permukiman dan perkantoran. Peningkatan kebutuhan ini yang melatarbelakangi perubahan fungsi lahan dari lahan kosong menjadi permukiman, atau contoh lainnya hutan menjadi perkantoran. Perubahan tata guna lahan tersebut membuat kemampuan daya resap air limpasan menurun dan meningkatkan kemungkinan terjadinya banjir atau kenaikan debit limpasan. Pemodelan rainfall run off menggunakan MIKE SHE akan merepresentasikan pengaruh tutupan lahan terhadap limpasan di DAS Ciliwung wilayah hilir pada tahun 2002 yang hasilnya dikalibrasi dan divalidasi dengan debit di Stasiun Pengamatan Pintu Air Manggarai. Luas tutupan lahan, koefisien aliran, koefisien Manning, dan indeks infiltrasi menjadi tiga parameter utama dalam pemodelan rainfall run off. Setelah dimodelkan, ketiga parameter menunjukkan sifat dependent terhadap variabel lain. Perubahan persentase nomenklatur tata guna lahan menjadi penyebab utama perubahan debit limpasan terhadap waktu.
Kata-kata Kunci: Debit, infiltrasi, koefisien, limpasan, model, tutupan.
Abstract
One of the changing variables that can affect the characteristics of the watershed and the hydrology of the watershed is land use change. The growth of the upstream, middle and downstream areas of the Ciliwung watershed in various sectors from Bogor, Depok to Jakarta greatly affects the land use conditions of the Ciliwung watershed. Jakarta as the capital city of Indonesia as well as the downstream area of the Ciliwung watershed is exposed to the most significant economic growth. This economic growth has become an attraction for urban and investors, resulting in an increase in the need for infrastructure such as settlements and offices. This increasing need is the background for changing the function of land from vacant land to settlements, or other examples of forests being offices. These land use changes reduce the ability of runoff to absorb water and increase the possibility of flooding or an increase in runoff discharge. Rainfall run off modeling using MIKE SHE will represent the effect of land cover on runoff in the downstream Ciliwung watershed in 2002, the results of which are calibrated and validated with discharge at the Manggarai Sluice Observation Station. Land cover area, flow coefficient, Manning coefficient, and infiltration index are the three main parameters in modeling rainfall run off. After being modeled, the three parameters show the nature of being dependent on other variables. Changes in the percentage of land use nomenclature are the main cause of changes in runoff discharge over time.
Keywords: Coefficient, coverage, discharges, infiltration, model, overflow.