Judul: Review of the Effectiveness of  Retention Ponds as Flood Control in the Housing Area of Summarecon Bogor
Abstrak: Salah satu upaya yang dapat dilakukan untuk pengendalian banjir adalah dengan pembuatan kolam retensi. Kolam retensi berfungsi untuk memotong puncak banjir yang terjadi dalam badan air / sungai dan sebagai pariwisata air. Penelitian ini dimaksudkan untuk mengkaji ulang efektivitas kolam retensi yang meliputi efektivitas tangkapan hujan dan efektivitas tampungan. Debit banjir rencana kolam retensi hasil Hidrograf Nakayasu distribusi 6 jam dengan periode ulang 25 tahun sebesar 97,67 m3 /detik. Elevasi muka air normal berada di +372,50 mdpl dengan luas genangan 8666,76 m2 dan volume tampungan 37138,85 m3 . Elevasi muka air banjir berada di +373,92 mdpl dengan luas genangan 9926,32 m2 dan volume tampungan 49631,60 m3 . Posisi kawasan kolam retensi Summarecon Bogor berada pada titik pengaliran catchment area, maka dapat diperkirakan bahwa efektivitas tangkapan kolam retensi sebesar 100%. Nilai active storage adalah sebesar 26,66%, namun tidak efektif untuk penampungan karena tidak dilengkapi bangunan pengatur outlet. Kedalaman aliran kritis pada bangunan spillway sebesar 1,42 m. Sebagai upaya penyempurnaan bangunan kolam retensi terbangun, diperlukan kajian lebih lanjut tentang saluran inlet dan bangunan pengatur outlet.
Keyword: capacity, design discharge, effectiveness, retention pond

Judul: Analyisis of the Effectiveness of Retention Ponds as Flood Prevention in Simpang Polda Area Palembang
Abstrak: Kota Palembang merupakan salah satu kota metropolitan yang terletak di Provinsi Sumatera Selatan. Proses urbanisasi dan meningkatnya pertumbuhan penduduk memberikan dampak pada penggunaan lahan sebagai daerah resapan air hujan. Penelitian ini bertujuan untuk mengetahui efektivitas kolam retensi di kawasan Simpang Polda Palembang yang berfungsi sebagai kolam penampungan air hujan dari Sungai Bendung menuju ke Sungai Musi. Tahapan penelitian meliputi beberapa tahapan seperti tahap persiapan, inventarisasi dan pengumpulan data, serta analisis dan sintesis. Hasil analisis hidrologi menunjukkan bahwa wilayah tertentu di Kota Palembang memiliki rata-rata curah hujan harian maksimum sebesar 56,34 mm, dengan daerah resapan air (catchment area) seluas 1.978.723,05 m2 (sebagian wilayah dari total luas DAS Bendung). Analisis hidrolika menunjukkan Qinflow sebesar 0,76 m3 /detik dan Qoutflow sebesar 20,28 m3 /detik. Hasil analisis kapasitas maksimum kolam retensi menunjukkan kolam retensi simpang Polda Palembang memiliki kapasitas maksimum 8.482,5 m3 hingga kolam penuh dalam waktu 186 menit. Berdasarkan hasil analisis tersebut dapat disimpulkan bahwa kolam retensi simpang Polda Palembang seharusnya dapat dengan optimal menampung air hujan yang jatuh di Kelurahan 20 Ilir D IV dan mengendalikan genangan air di kawasan Simpang Polda Palembang. Menurut Tim BBWS VIII Sumatera Selatan, pengendalian luapan air di Kawasan Simpang Polda dapat dilakukan dengan melakukan normalisasi terhadap kolam retensi dan aliran sub das secara rutin. Namun, untuk menjaga keseimbangan alam, diperlukan beberapa perencanaan lain, salah satunya dengan memperbaiki saluran drainase di sekitar kolam retensi., Palembang City is one of the metropolitan cities located in South Sumatra Province. The process of urbanization and increasing population growth has an impact on land use as a rainwater catchment area. This study aims to determine the effectiveness of retention ponds in the Simpang Polda Palembang area which function as rainwater storage ponds from the Bendung River to the Musi River. The stages of the research include several stages such as preparation, inventory and data collection, as well as analysis and synthesis. The hydrological analysis results show that certain areas in Palembang City have an average maximum daily rainfall of 56.34 mm, with a catchment area of 1,978,723.05 m2 (part of the total area of the Bendung River Basin). Hydraulics analysis showed that Qinflow was 0.76 m3 /second and Qoutflow was 20.28 m3 /second. The results of the analysis of the maximum capacity of the retention pond show that the retention pond of the Palembang Police intersection has a maximum capacity of 8,482.5 m3 until the pool is full in 186 minutes. Based on the results of this analysis, it can be concluded that the retention pond for the Palembang Police intersection should be able to optimally accommodate rainwater that falls in 20 Ilir D IV Village and control standing water in the Palembang Police Intersection area. According to the South Sumatra BBWS VIII Team, controlling water overflow in the Polda Simpang Area can be done by routinely normalizing the retention pond and sub-watershed flows. However, to maintain the natural balance, several other plans are needed, such as by improving the drainage channels around the retention pond.
Keyword: Analisis hidrologi, Kolam retensi, pengendalian banjir, Hydrological analysis, retention Pond, flood control

Judul: Phylogenetic analysis of subgenus Dieramalpinia (Alpinia carolinensis clade) - Zingiberaceae based on ITS sequences
Abstrak: The most recent infra-generic classification of Alpinia Roxb. by Smith divided the genus into two subgenera (Alpinia and Dieramalpinia) with 11 sections and 12 subsections. One of the sections of Alpinia subgenus Dieramalpinia is Myriocrater which contains about 16 species. The most recent phylogenetic study that included species from Alpinia subgenus Dieramalpinia was done by Kress et al. (2007). They sampled only eight species and found that these were nested within a clade referred to as the Alpinia carolinensis clade. This clade was well supported and may be separated as a genus if sampling more species confirms the result. The objectives of the present project are to compare ITS within one species; to test the monophyly of Alpinia section Myriocrater; to test whether adding more samples still supports the Alpinia carolinensis clade. The present study included thirty-nine samples representing nineteen taxa from Alpinia; seven samples are still unidentified at species level. Sequences of the Internal Transcribed Spacer were used in the analysis. The result showed that ITS sequence of Myriocrater’s species are more conserved than another group in Zingiberaceae. There are base variations within species level. The Alpinia section Myriocrater plus five species from other section is not monophyletic. The Alpinia carolinensis clade still includes three sections of Smith classification (Dieramalpinia, Myriocrater and Pycnanthus) from subgenus Dieramalpinia. Alpinia subgenus Dieramalpinia section Eubractea and one species of section Dieramalpinia are separated into another clade.
Keyword: Alpinia, Myriocrater, Dieramalpinia, Alpinia carolinensis clade