Electronic Theses and Dissertation

Kolam retensi oxbow lake memainkan peran krusial dalam menjamin ketersediaan air
untuk kebutuhan di hilir. Dengan mengatur pelepasan air dari kolam retensi oxbow lake,
variabilitas temporal aliran dapat dikurangi. Kolam retensi oxbow Krueng Tamiang
berlokasi di DAS Krueng Tamiang. Sistem pengoperasian kolam retensi oxbow Krueng
Tamiang untuk menyuplai kebutuhan air irigasi dan air bersih. Hal yang terpenting sistem
kolam retensi memerlukan sistem pelimpah untuk menjaga keamanan kolam dari
overtopping pada kondisi kelebihan air. Maka penelitian ini bertujuan untuk menganalisis
penelusuran banjir kolam retensi oxbow Tamiang. Berdasarkan hasil penelitian diperoleh
debit banjir periode ulang 2 tahun sebesar 2.810,51 m3/dt. Dengan dibangun tanggul pada
kolam retensi oxbow maka kapasitas diperoleh sebesar 1.147.528 m3. Berdasarkan flood
routing sungai dengan debit banir periode ulang 2 tahun diperoleh nilai ketinggian muka
air banjir maksimum pada inlet yaitu 14,67 m pada elevasi ±7,14 mdpl, maka dibangun
tanggul dengan ketinggian mencapai elevasi ±8 mdpl. Pada penelusuran banjir jam ke-9
terjadi debit outflow sebesar 1,50 m3/dt, maka diperlukan spillway pada outlet kolam.
Selain spillway pada outlet juga difasilitasi pintu air yang berfungsi utama untuk
mengeluarkan sedimen. Dimensi pelimpah inlet diperoleh lebar 22 m dan elevasi ±5 mdpl
sebagai elevasi crest pelimpah, sedangkan dimensi pelimpah outlet diperoleh lebar 4 m dan
pintu air pada outlet dengan bukaan 1 meter sebesar 3,99 m3/dt. Penelusuran banjir
memperhitungkan efektivitas pengurangan debit puncak banjir sebesar 4%. Kolam retensi
memiliki multi fungsi sebagai infrastruktur pemangkas puncak banjir dan yang lebih utama
sebagai infrastruktur pemenuhan kebutuhan air irigasi dan air bersih.

Oxbow lake retention ponds play a crucial role in ensuring the availability of water for downstream needs. By regulating the release of water from oxbow lake retention ponds, the temporal variability of flow can be reduced. The Krueng Tamiang oxbow retention pond is located in the Krueng Tamiang watershed. The operating system of the Krueng Tamiang oxbow retention pond to supply irrigation water and clean water needs. The most important thing is that the retention pond system requires an overflow system to maintain the safety of the pond from overtopping in excess water conditions. Therefore, this study aims to analyze the flood tracing of the Tamiang oxbow retention pond . Based on the results of the study, the flood discharge for the 2-year re-period was 2,810.51 m3/s. By building an embankment in the oxbow retention pond, the capacity is obtained of 1,147,528 m3. Based on river flood routing with a 2-year re-release period, the maximum flood water level value at the inlet was 14.67 m at an elevation of ±7.14 meters above sea level, then an embankment was built with a height of ±8 meters above sea level. In the 9th hour flood tracing, there was an outflow discharge of 1.50 m3/s, so a spillway was needed at the pool outlet. In addition to spillways at the outlet, sluices are also facilitated which have the main function to remove sediment. The dimensions of the inlet overflow were obtained with a width of 22 m and an elevation of ±5 meters above sea level as the elevation of the overflow crest, while the dimensions of the outlet overflow were obtained as a width of 4 m and the sluice gate at the outlet with an opening of 1 meter of 3.99 m3/s. Flood tracing takes into account the effectiveness of reducing peak flood discharge by 4%. Retention ponds have multiple functions as flood peak trimming infrastructure and more importantly as infrastructure to meet irrigation water and clean water needs.