Joko Sujono

Vagueness ratio of storage function model parameters and its relation to the accuracy of hydrograph prediction

Fuzzy linear regression (FLR) has been applied in many areas, including several areas of engineering. For instance, it has been successfully applied in conceptual rainfall runoff modeling to identify the parameters of the storage function (SF) model. In the FLR, each model parameter is not a crisp value as found in traditional procedures but the model parameters have a fuzziness value characterized by the center (α) and the width (c) values. The width value could be further analyzed in terms of its contribution in the prediction accuracy. In this case, the vagueness ratio, defined as a ratio between the width value and its center value for the model parameters, is presented here as a surrogate for analyzing any possible relation to the prediction accuracy. Application of the vagueness ratio to a number of flood hydrographs at Ochohzu basin in Fukuoka, Japan, shows that the ratio is useful for assessing the accuracy of the hydrograph prediction; i.e., the higher the value of the ratio indicates the less accuracy in the prediction.

Restoration of peat dome in ex-Mega rice project area in Central Kalimantan

Restoration has been carried out on several tropical peatland water systems in Indonesia. One of them held at ex-Mega Rice Project Area (EMRP) of a million hectare of peatland in block A, Sei Ahas Village, Mentangai, Kapuas District, Central Kalimantan. The method was used to create a canal blocking in several locations which was expected to increase water table level and to repair degraded peatland ecosystems. In this recent research, two cases of blocking in canal D and E had been compared to canal C condition without blocking of water table in upstream blocking and peatland ecosystems. Based on 3 years field observations in restoration process and secondary data in peatland water system by canal blocking constructing, there was finding obtained by the presence of the block on canal E, water table in upstream canal can be maintained at time of rainy season and dry season/ Therefore, the peatland might be inundated. In canal C with no blocking, the level was 0.2 m above the bottom of the canal at the end...

Analysis of intake gate operation of the three weirs in Bedog river

The problem of climate change and agricultural practices could not be anticipated by the intake gate operator. Such changes need to be monitored and assessed in order to supply the irrigation water to the command area. This study is was carried out to analyze the intake gate operation in three weirs (Cokrobedog, Gamping and Pendawa) located in Bedog river. The method used in this study was the quantification analysis I. Input data for this method were the discharge entering through the weir, rainfall and agriculture commodities (paddy or palawija). Those data were divided into item 1,2,3, and 4 were each divided into 2,5,3, and 3 catagories respectively. The study was conducted within one year of planting season. The analysis showed that intake gate operation of Cokrobedog, Gamping and Pendawa affected by age of commodities, kind of commodities and irrigation water availability, respectively. This suggests that, in general, the availability of irrigation water for all command areas of the three weirs was ...