Diajukan Diperbaiki DisetujuiKeywords: Irrigation System, budget, value of priority, value of benefit, linier programming.Blimbing Irrigation Area covers 319 Ha of agriculutural land. Damages were observed on irrigation system. This resulted in decreased function of irrigation system. Maintenace activities are required to restore the fuction of irrigation system. The purpose of thi research is to obtain optimal strategy of maintenance irirgation system on Blimbing Irrigation Area, while the constraint is the cost limitation. The initial phase is to identify and assess the damage on Blimbing Irrigation Area and make value of priority for maintenace irrigation. Then calculate Benefit and Cost to assess the feasibility maintenace activities. This research uses Linnier Programming method wich consist of objective functions and constraint functions. The objective function for this research is to maximize the value of priority or the value of benefits, while the constraint is the cost limitation. Reffers to the cost Rp. 100.000.000, the optimization was applied to maximimize the value of priority or the value of benefit. The results were 7 segment can be repaired with the budget of Rp. 99.998.887. Optimization result by maximized the priority value is the same as optimization result by maximized th benefit value.Kata kunci: jaringan irigasi, anggaran, nilai prioritas, nilai manfaat, linier programming. Abstrak Daerah Irigasi (DI) Blimbing mengairi lahan pertanian sebesar 319Ha. Kondisi fisik jaringan irigasi banyak mengalami kerusakan yang mengakibatkan menurunnya fungsi jaringan irigasi. Sehingga diperlukan pemeliharaan untuk mengembalikan fungsi jaringan irigasi ke kondisi semula. Tujuan dari penelitian ini adalah untuk memperoleh strategi pemeliharaan jaringan irigasi DI Blimbing yang optimal, dengan memperhatikan biaya. Tahap awal adalah mengidentifikasi, menilai kondisi fisik dan fungsi bangunan irigasi dan membuat urutan prioritas pemeliharaan jaringan irigasi. Kemudian menghitung Benefit and Cost untuk menilai kelayakan. Penelitian ini menggunakan Metode Linier Programming yang terdiri dari fungsi tujuan dan kendala. Sebagai fungsi tujuan adalah memaksimumkan nilai prioritas/nilai manfaat, sedangkan untuk fungsi kendala yaitu keterbatasan biaya. Mengacu biaya sebesar Rp. 100.000.000, permodelan/optimasi pemeliharaan yang dikaitkan untuk memaksimalkan nilai prioritas atau nilai manfaat diperoleh ruas yang dapat diperbaiki sebanyak 7 ruas dengan anggaran sebesar Rp. 99.998.877. Hasil optimasi dengan memaksimalkan nilai prioritas sama dengan hasil optimasi dengan memaksimalkan nilai manfaat.

Ampal Catchment Area has 25.273 km2 area and 4.699 km main river length, which planned to have 13 flood control construction. Until 2017, this catchment area has only three flood control construction. The watershed has only three built-in batters that are used to reduce the amount of flood discharge flowing on the Ampal river. Based on these conditions, it is necessary to analyze the magnitude of the difference of flood peak discharge on the existing condition (three bendali) compared with the condition of the plan (thirteen bendali). Therefore, analyzed the function and influence of flood control construction in Ampal Catchment Area by counting the flood peak discharge in each condition. From the analysis result, obtained the amount of peak discharge flowing in Ampal river existing condition is equal to 170,40 m3/s while at the condition of plan is equal to 83,80 m3/s. From the results of analysis, it is stated that the magnitude of the decrease of debit (ΔQ) after all the builds is 86.60 m3/s.

Disaggregation of hourly rainfall data is very important to fulfil the input of continual rainfall-runoff model, when the availability of automatic rainfall records are limited. Continual rainfall-runoff modeling requires rainfall data in form of series of hourly. Such specification can be obtained by temporal disaggregation in single site. The paper attempts to generate single-site rainfall model based upon time series (AR1) model by adjusting and establishing dummy procedure. Estimated with Bayesian Markov Chain Monte Carlo (MCMC) the objective variable is hourly rainfall depth. Performance of model has been evaluated by comparison of history data and model prediction. The result shows that the model has a good performance for dry interval periods. The performance of the model good represented by smaller number of MAE by 0.21 respectively. Keywordstemporal rainfall, hourly, Bayesian time series AbstractDilakukan percobaan untuk mengidentifikasi hubungan antara kecocokan sruktur model hujan time series terhadap disagregasi pola kejadian hujan dan tinggi hujan serta akan mempresentasikan prosedur untuk pemilihan struktur model guna penelitian model disagregasi hujan. Tiga model time series hujan jam-jaman telah di ujikan pada stasiun hujan Sental di daerah aliran sungai Sampean di Bondowoso. Struktur model merupakan kombinasi model autoregresi, moving average, musiman, dummy dan prosedur adjusting. Estimasi model menggunakan Bayesian. Poin penting untuk menentukan struktur model yang tepat akan dipilih berdasarkan nilai error terkecil dari model, periode waktu kedatangan hujannya, kondisi tidak terjadi hujan dan kondisi puncak tinggi hujan. Hasil studi mengindikasikan bahwa model AR 1 musiman dengan Dummy merupakan model yang tepat untuk memodelkan disagregasi hujan. Dimana model mampu memberikan nilai error terendah, pola kejadian hujannya sesuai dengan kondisi observasi, dapat mewakili kondisi saat tidak terjadi hujan dan memberikan nilai puncak hujan tertinggi dari model lainnya. Kata Kuncihujan temporal, setiap jam, time series Bayesian

AbstrackKonawe known as an area that plays an important role in agricultural production in Southeast Sulawesi particularly rice and pulses. Most of Irrigation in Indonesia has not been optimal in the management as influenced by several factors that need to be examined, one of which has not been optimal in performance management is Wawotobi Irrigation Area. Irrigation area is currently carried out by the technical manager

Abstract-Water is the natural resources have the function of very importance for human life and also as authorized capital in development. Water will influence by the other component. Exploiting of water to support all human life must done with wise action to management so that not result damage at water resource. As place relocation of water hence river have the selected capacities that able to change because natural activity and antropogenik. This research was conducted in nine major rivers in East Java. The objectives of this study were: 1) Identifying the characteristics and concestration range of water quality parameter, 2) Comparison the level of pollution in rivers in East Java. The results of this study indicated that the characteristic of water quality parameter of rivers in East Java were generally physical, chemical and biological. The comparison result of water quality parameter basically showed that in general the pH was still under threshold that had been determined, that was pH from 6 to 9. In general, DO concentration ranged from 0.5 mg/l to 7 mg/l, BOD concentration ranged from 3 mg/l to 11 mg/l and the COD concentration ranged between 0.5 mg/liter to 35 mg/l.