Predicting Discharge From Agricultural Catchment to Support Land and Water Management in Singkarak Basin, West Sumatra

Limited hydrological data in Paninggahan sub catchment in Singkarak basin has resulted in inappropriate land management practices for farming system development. Predicting stream flow using an appropriate hydrological model is critical for a catchment with limited data recording. The present study has been conducted from January 2006 to December 2007. The objective of this study is to characterize hydrological condition of the catchment and to predict river flow for supporting design of landand water management options. To some extend, the study is to provide inputs in negotiation of farmers community with other stakeholders in the Singkarak basin. An automatic water level recorder (AWLR) and an automatic weather station (AWS) have been installed in the catchment to record hydro-meteorological data in order to calibrate hydrological model for predicting river flow. An instantaneous discharge model based on Geomorphological Instantaneous Unit Hydrograph (H2U) and a daily discharge model of GR4J were used to predict the river flow. The instanteneous hydrological data suggested that stream discharge sharply increased during onset rain and implying that the draining water was dominated by rapid flow. After peak storm has been reached, the water was slowly released to the river the one is typical hydrological process for disturbed catchments where rainfall water may no longer be retained in thecatchment. Application of both hydrological models in Paninggahan sub catchment during a period of March to April 2006 has given an appropriate result. The GR4J model has been calibrated and has given the value of similarity coefficient of 87.9%, while calibration of H2U model applied for storm event and has given the value of similarity coefficient of 96%. Thesucceed of predicting discharge using both models is valuable to support planning program in land and water management for farming system development in the Singkarak basin

Hydrological Model of Upstream Aih Tripe Watershed for Drought and Flood Prediction

The objectives of this research is to analyze biophysic caharacteristics of Upstream Aih Tripe Watershed and to predict discharge characteristic of Aih Tripe River based on hydrological models application. Modified H2U model is applied to predict instantaneous discharge, meanwhile GR4J model is applied to predict daily discharge. Upstream Aih Tripe characteristics are,1,115.2 km2 wide, stretch watershed type (Gravelius index 4.31), equivalent length (L) 252.40 and equivalent width (l) 4.42, parallel drainage pattern, maximum river order is 5 and drainage dencity 1.37 m m-2, global slope index (Ig) 2.0 and specific high different (Hg) 0.06. Instantaneous discharge simulation results at dry season are: instantaneous maximum discharge is 364.8 m3 s-1 and time to peak 4 hours, rainfall maximum intensity is 29 mm hour-1, rainfall is 45.9 mm with duration 5 hours. In rainy season, maximum discharge is 605.2 m3 s-1 and time to peak 2 hours, rainfall maximum intensity is 40.8 mm hour-1, rainfall is 73.2 mm with duration 7 hours. Maximum discharge during El Nino condition is 131.4 m3 s-1 (30 September) and minimum dischargeis 8.2 m3 s-1 (31 March). Discharge simulation during La Nina, maximum discharge is 328.3 m3 s-1 (11 December) and minimum discharge is 8.5 m3 s-1 (5 October)

Alternative Method for Calculating Runoff Coefficient Based on Discharge Simulation Model by Applying Unit Hydrograph Concept (Kali Kripik Sub Watershed Case Study)

Comparison of two method on calculating runoff coefficient (Cr), is discussed in this paper i.e. classical method and alternative method. The first one calculates Cr based on the hydrograph separation analyses, and the second one based on the discharge model simulation by applying unit hydrograph concept. The classical Cr values is calculated using simple method and the alternative Cr values is calculated using H2U (Hydrogramme Unitaire Universel) transfer rainfall-discharge model, for 47 rainfall and discharge events from September 1998 to March 1999 on Kripik sub Watershed. The H2U model calculates discharge based on convolution product between excess rainfall and hydrological network density that was represented by probability density function. The Cr value according to this model is determined when the Cr is resulting the best discharge simulation. During the period of September 1998 to March 1999, the classical Cr value varied between 2,8 to 69,1%, while alternative Cr between 1,0 to 48,8%. The smallest and the biggest differences between classical and alternative Cr values were 0,3% and 26,5%, respectively. According to regression analyses and Nash-Sutcliffe criterion, the coefficient of determination (R2) and the coefficient of efficiency (F) were 0,9312 and 0,6829, respectively. Statistically, these values indicate that the alternative Cr value was similar to classical one

Production and Quality Enhancement of Mango Using Fan Jet Sprayer Irrigation Technique

Lack of water in reproductive phases (flowering, fruit formation and maturation) of mango can reduce fruit production and quality. In these phases the plant must be protected from water stress. The aim of the research was to assess the effect of irrigation on the productivity and quality of mango fruits. The study was conducted at the Cukurgondang Experimental Station, Pasuruan, East Java, from April to December 2013, using 40 mango trees of 21 year-old Arumanis variety. Mangoes were planted on five rows with eight plants for each row and 6 m x 6 m spacing within the row. Fan jet sprayer irrigation was installed using hose according to plant diameter. The irrigation technique of fan jet sprayer with four nozzles per plant was applied at 125, 100, 75, 50 and 0% of crop water requirements or equal to 828, 663, 497, 331 and 0 liters of water per tree, every seven days. The parameters observed were the number and weight of fallen fruits and the number, weight and quality of mangoes harvested. The results showed that irrigation of 50% and 75% of crop water requirement had the highest and lowest number of fallen fruits (26% and 14% of total production), respectively. The highest and lowest total number of mangoes were 3.108 and 1904 fruits, respectively, which were achieved at irrigation of 50% and 75% of crop water requirement. Further, the highest and lowest total weight of mango fruits were 1036.2 and 677.9 kg respectively which were achieved at irrigation of 50% and 125% of crop water requirement. Mango fruits produced were dominated by grades 2 and 3 with A quality

Pemberian Mulsa dalam Budidaya Cabai Rawit di Lahan Kering: Dampaknya terhadap Hasil Tanaman dan Aliran Permukaan

The problem of plant cultivation in dry upland with slope of >15° is the high soil erosion that result in high rate of sedimentation in the downstream of watershed. One way of overcoming this problem is by utilization of mulches. The objective of the experiment was to study the effect of mulch application on growth and yield of chilli (Capsicum frutescensL.).The experiment was conducted from January 2010 until June 2011 at Selopamioro micro watershed at Imogiri Subdistrict, Bantul District, Special Region of Yogyakarta. The experiment was arranged in a randomized complete block design consisted of four mulch treatments (rice straw, litter, plastic/silver black polyethylene, and without mulch) and four replications. The observed variables were the growth parameter (plant height), soil moisture content, soil temperature, and yield (number and weight of chilli). The result showed that application of mulches did not affect plant height and yield of chilli, but increased number of fruit. The best mulch for chilli crops in upland area was rice straw, that yielded the highest increase in number of fruit. Mulch as a soil conservation practice reduced runoff coefficient, while dicharge and extended of the reponse time were reduced only at rainfall less than 21 mm

Analytical model for a geomorphological instantaneous unit hydrograph

International audienceThe rainfall-runoff modelling of a river basin can be divided into two processes: the production function and the transfer function. The production function determines the proportion of gross rainfall actually involved in the runoff. The transfer function spreads the net rainfall over time and space in the river basin. Such a transfer function can be modelled using the approach of the geomorphological instantaneous unit hydrograph (GIUH). The effectiveness of geomorphological models is actually revealed in rainfall-runoff modelling, where hydrologic data are desperately lacking, just as in ungauged basins. These models make it possible to forecast the hydrograph shape and runoff variation versus time at the basin outlet. This article is an introduction to a new GIUH model that proves to be simple and analytical. Its geomorphological parameters are easily available on a map or from a digital elevation model. This model is based on general hypotheses on symmetry that provide it with multiscale versatile characteristics. After having validated the model in river basins of very different nature and size, we present an application of this model for rainfall-runoff modelling. Since parameters are determined relying on real geomorphological data, no calibration is necessary, and it is then possible to carry out rainfall-runoff simulations in ungauged river basins. Copyright (c) 2006 John Wiley \& Sons, Ltd

Pemodelan Debit Aliran Permukaan Berdasarkan Aplikasi Konsep Horton dan Hidrograf Satuan pada DAS Mikro Kertek Wonosobo, Jawa Tengahdischarge Run Off Simulation Model Based On Application Of Horton's Concept And Unit Hydrograph On Kertek ...

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Pengaruh Sifat Hujan dan Kerakteristik Biofisik DAS terhadap Debit Banjir DAS Kaligarang, Semarangeffect Of Watershed Rainfall And Biophysics Characteristic Toward Flood Debit Of Kaligarang Watershed, Semarang

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