Rationalization of Rainfall Station Network in Welang Watershed Using Kagan-Rodda Method

Rationalizing rainfall station is important to get an effective and efficient number and distribution of rainfall stations. If rationalization isn’t carried out, it affect to operating and maintenance costs of rainfall stations and accuracy of data. This study aimed to evaluate existing rainfall station and rationalize rainfall station, so rainfall station’s location is evenly distributed. This study is located in Welang watershed with an area 477.78 km2. This research requires rainfall ground data from 9 rainfall stations and CHIRPS satellite rainfall data from Google Earth Engine. The data is tested with consistency, stationary, suitability, and rationalization based on World Meteorological Organization (WMO) standards and Kagan-Rodda method. Later, new rainfall station networks will be obtained with the influence area of rainfall stations suitable to WMO Standard. CHIRPS data is highly suitable with ground data, proven by high NSE, strong correlation, and low relative error, so CHIRPS data can be used for further analysis. According WMO, only 1 rainfall station in Welang watershed has been suitable for WMO standard. Those unsuitable with WMO standards need to be rationalized. Based rationalization results, with average error <10%, Welang watershed requires 4 rainfall stations by maintaining Lawang Station, moving Telebuk to Station B, Selowongko to Station C, and Tutur to Station D. The influence area of recommendation rainfall stations have been suitable to WMO Standards and obtained even distribution rainfall stations. This recommendation are expected to be considered by relevant institutes to move the location of the rainfall station to get more accurate rainfall data

Performance of The Dispin Models with Automatic Parameter Calibration on The Transformation of Rainfall to Runoff Data

This article presents a new model of the DISPRIN Model combination with two different level optimization methods. The new model of DISPRIN Model combination and Differential Evolution (DE) algorithm is called DISPRIN25-DE Models and its incorporation with Monte Carlo Simulation method called DISPRIN25-MC Models. The case study is Lesti Watershed (319.14 Km2) in East Java. The model test uses a 10-year daily data set, from January 1, 2007 to December 31, 2016. Data series Year 2007 ~ 2013 as a set of training data for calibration and data Year 2014 ~ 2016 as testing data set for model validation. Running program DISPRIN25-DE Models with input parameter value C_min = 0, C_max = 1, H_min = 0, H_max = 600 mm obtained best fitness 0.044 m3/sec, NSE = 0.762 and PME = -0.059. The DISPRIN25-MC Models analysis generates a minimum RMSE of 0.056 m3/sec, NSE = 0.779, PME = -0.70. From the RMSE and NSE indicators it appears that both models can show an equivalent level of performance, but in terms of the PME indicator and iteration time is apparent The DISPRIN25-MC model has worse performance than the two DISPRIN25-DE models

Rasionalisasi Jaringan Penakar Hujan Di Das Kedungsoko Kabupaten Nganjuk

Kedungsoko River and its tributaries is located in Kediri and Nganjuk district. Kedungsoko river has approximate 416,54 km2 of watershed area number. Kedungsoko catchment area is affected by approximate 8 rain stations. There has not been studied theoretically about the optimum density and dispersal patterns of rainfall station networks that have been installed in the Kedungsoko watershed. Based on the results of assessment and analysis using Kagan-Rodda method, it was acquired 4 selected stations, while Kriging method obtained results of 8 selected stations that spreaded in Kedungsoko watershed. Relative error for design rainfall of Kagan-Rodda method is 1,906% and Kriging method is 2,802%. Relative error of hidrograf discharge unit for Kagan-Rodda is 38,53% and 19,83% for Kriging. Keywords: Rainfall station networks, Kagan-Rodda, Krigin

PENGARUH PERUBAHAN IKLIM TERHADAP OPTIMASI KETERSEDIAAN AIR DI IRIGASI WAY MITAL PROPINSI MALUKU

Global climate change affects to temperature, relative humidity, solarradiation length, wind speed, rainfall and river discharge. Due to climate change the high of rainfall intensity impact on river discharge fluctuations in the wet anddry season. Floods and droughts as anatural event are more often occurred at this time. Waymital Irrigation area has a127 hectares command area consisting of the fourtertiary those are 7 hectares Kairatutertiary, 10 hectares Gembatertiary, 10 hectares Hatusuatertiary and 100 hectares way Mitaltertiary, therefore to deal with that extreme impact, required a systematically irrigation management plansin order to be still profitable, especially for farmers. The methodology used in the analysis of irrigation water availability optimization at Mital Way command area using the Simplex Linear Programming that will be obtained cropping area, discharge and maximum benefit of agricultural production. Based on the analysis results indicates that has occurred the climate change on Way mital command area in 2009 that is marked by a shifted in the rainy and dry seasons and increased the amount of annual rainfall. Increasing the amount of rainfall has an impact on the volume availability of water intake changes, before the climate change, the volume availability of water intheintake (cropping season) are MTI =699000 m3, MTII = 444 000 m3and MTIII =502 000 m3. While from the study result also showed that after the occurrence of climate change, volume of water available in the intake are MTI =715000 m3, MTII = 487000 m3and MTIII =537000 m3. Volume of water availability from the optimization of the existing cropping pattern at Way Mitalboth before and after climate change is still sufficient to water requirement for everycropping season and the difference inprofit is 418.875.000 rupiahs peryear which is obtained from agricultural production. Keywords: Climate Change, WaterAvailability, Linear Programming

Studi Analisa Kebutuhan Jumlah Stasiun Hujan Berdasarkan Evaluasi Perbandingan Antara Analisa Hidrograf Banjir Dan Banjir Historis Pada Das Limboto Provinsi Gorontalo

In the hydrologic analysis activities, the Errors in basic hydrological data monitoring in a drainage area of the river will result in data are not correct and lead to the result of planning and management of water resources is not efficient and effective. The errors are usually caused by a number of rainfall stations in the watershed inadequate and dispersal patterns of uneven rainfall stations. The purpose of this study is to obtain the results of the evaluation of the amount of rainfall stations WMO standards based on existing conditions, to determine the comparison between the design flood discharge KaganRodda method and the design flood discharge conditions using the existing station network, and to obtain recommendations amount and location of rainfall stations positions. This study conducted in watershed of Limboto, with an area of watershed is 902.91 km2 .The results of this study are recommending 16 rainfall stations where the 4 stations is the existing stations, with each station rainfall density is 8.038 km. Keywords: Flood, Kagan-rodda, Rain Station, Rain Station density

Analisis Optimasi Untuk Prioritas Pembangunan Embung Berbasis Ketersediaan Air Di Kecamatan Kedungadem Kabupaten Bojonegoro

Kecamatan Kedungadem berada di Kabupaten Bojonegoro yang pada setiap tahunnya mengalami kekeringan. Diperlukan program peningkatan kapasitas embung secara bertahap. Untuk menentukan alokasi anggaran dana, dilakukan pemilihan tiga embung prioritas. Penelitian ini ditujukan untuk dasar penentuan pemilihan lokasi embung. Pemilihan embung prioritas menggunakan analisa manfaat keuntungan terbesar dengan berbasis ketersediaan air. Dari analisa manfaat keuntungan diperoleh prioritas pembangunan embung meliputi Embung Panjang, Embung Kepohkidul Dusun Pedang dan Embung Sidomulyo. Optimasi dilakukan dengan alokasi anggaran dana pada embung tersebut, agar menghasilkan keuntungan untuk irigasi. Dengan menggunakan metode dinamik stokastik, apabila kebijakan alokasi anggaran dana diterapkan, akan menghasilkan keuntungan yang jauh lebih besar apabila anggaran dibagi rata untuk ketiga embung tersebut. Jika dilakukan sesuai dengan perhitungan optimasi, nilai benefit cost ratio yang diperoleh sebesar 1.71. Akan tetapi apabila tidak diterapkan optimasi, benefit cost ratio yang diperoleh sebesar 0.67

ANALISIS HUJAN DAN TATA GUNA LAHAN TERHADAP LIMPASAN PERMUKAAN DI SUB DAS PEKALEN KABUPATEN PROBOLINGGO

Abstrak : Tata guna lahan daerah aliran sungai yang mengalami perubahan dan mengarah pada penggundulan hutan dapat meningkatkan debit banjir serta mempengaruhi debit rerata harian  sungai di daerah hilir. Debit sungai yang mengalir merupakan  respon daerah aliran sungai, dengan masukan hujan dan digambarkan melalui karakteristik hidrograf aliran sungai. Sub DAS Pekalen mempunyai luas 165,49 km2, berada di Kabupaten Probolinggo. Rata rata debit  harian  yang mengalir tahun 1997 sebesar 8,843 m3/dt dan tahun 2006 sebesar 10,42 m3/dt. Hasil analisa peta tata guna lahan tahun 1997 dan tahun 2006 menunjukkan adanya perubahan tata guna lahan. Berdasarkan analisa limpasan permukaan metode Curve Number dengan software HEC HMS menunjukkan bahwa perubahan tata guna lahan yang mengakibatkan nilai Curve Number meningkat 0,59% maka, debit banjir yang akan terjadi juga mengalami peningkatan sebesar 1,99%. Kata Kunci :  Tata Guna Lahan, Curve Number, HEC HMS, Sungai Pekalen   Abstract : The change of land-use in watersheds and deforestation may increase flood discharge and affect the average daily flow of the downstream. The river discharge is a response to the watershed, with the input of rain and illustrated by the characteristics of hydrograph. Pekalen sub watershed has an area of 165,49 km2, located in Probolinggo. The average daily discharge in 1997 is 8,843 m3 / sec and 2006 is 10,42 m3 / sec. The results of the analysis of land use maps of 1997 and 2006 showed changes in land use. Based on the analysis of surface runoff Curve Number method with use HEC HMS software showed that the land use change by increasing the value of Curve Number 0,59%, the flood discharge will be also increased 1,99%. Keywords : Land use, Curve Number, HEC HMS, Pekalen rive

Climate Changed Effect on Irrigated Water Supply at Segaran Malang, Indonesia

This paper studied the effect of climate change to optimization of irrigated water supply atSegaran Irrigation Area. Global climate exchange caused some effects to hydrological factorssuch as temperature, humidity, seasonal time exchange and the quantity of rainfall. These exchanges would give contribution exchange to the operation of water irrigation. The methodology consisted of optimization irrigated water supply with Simplex Linear Programmingfor two time series such as before and after climate exchange. Results can use as the pattern of allocating water supply at Segaran irrigation area, due to the effect of climate exchange. Global climate exchange did not cause irrigated water supply and crop intensity. Key words: climate exchange, irrigation water, linear programmin

Analisis Perubahan Bilangan Kurva Aliran Permukaan (Runoff Curve Number) Terhadap Debit Banjir Di DAS Lesti

Land use activities that changing types of land cover, vegetation changes to other vegetation types in managed of natural resources, deforestation, shifting cultivation, and changes in land treatments found in the watershed Lesti. Efforts that can be used as an alternative solution to the landuse change is to analyze the CN (Curve Number) as a variable that classify each landuse, type of soil and vegetation, in order to know the effect of the runoff and river discharge. The study shows CN value increase from 2002 to 2012 an average of 1.03%, average surface runoff 54.79 mm, with an average streamflow of 18.54 m 3 / sec. The changes in land use from 2002 to 2012 caused increase in the value of the CN (Curve Number), surface runoff, and river discharge in Lesti River. Key words: Lesti Watershed, Curve Number, Runof