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The Wonogiri Reservoir is a multipurpose reservoir at the Upper Bengawan Solo Watershed, primarily designed to serve as a flood control system. However, there is no accurate estimation of the inflow into the reservoir due to the limited availability of hydrological stations. Observations showed only four out of ten unit hydrographs of the Wonogiri Reservoir watershed. Therefore, this study was conducted to apply an integrated similarity-based approach for designing unit hydrographs in ungauged catchments. The process involved evaluating the integrated similarity between pairs of gauged-ungauged catchments using hydrologic and physical property parameters. This led to the selection of the donor or gauged catchment with the highest similarity score to develop the unit hydrograph for the ungauged catchments. The developed UHs were further applied to estimate the reservoir inflow for the December 25, 2007, flood event. The results showed that the computed peak discharge was 10.9% lower than a previous study. Subsequently, the HEC-HMS simulation model was used to project the updated design flood hydrographs to the reservoir. The design rainfall was derived from automatic rainfall recorder (ARR) and PERSIANN satellite-based data. The ARR data showed that the extreme rainfall duration was 5 hours while satellite data indicated 6 hours. The application of the ARR 5-hour duration to the updated flood hydrographs led to a peak discharge of 5123 m3 s-1, 7041 m3 s-1, and 10,370 m3 s-1 for the 60-year, 500-year, and PMF floods respectively in line with the flood design criteria of Wonogiri Reservoir. These estimates were observed to be significantly higher than the 1982 design floods which were 4000 m3 s-1, 5100 m3 s-1, and 9600 m3 s-1 respectively. This updated flood control design was important to renew the operation rule of the Wonogiri reservoir during flood periods.

Waduk Wonogiri di Bengawan Solo hulu telah mengalami permasalahan sedimentasi yang mengganggu operasionalnya. Sebagian besar sedimen berasal dari DAS Keduang di sisi kanan (timur) waduk. Untuk mengatasi permasalahan tersebut, sebuah closure dike telah dibangun untuk melokalisasikan pasokan sedimen dari DAS Keduang. Closure dike membagi waduk menjadi waduk utama dan waduk tampungan sedimen, masing-masing memiliki pelimpah. Makalah ini menyajikan hasil kajian operasi Waduk Wonogiri dalam pengendalian banjir setelah pembangunan closure dike. Studi terdiri dari dua tahap. Tahap pertama adalah pemutakhiran banjir rancangan dengan menggunakan metode analisis frekuensi data hujan dan hidrograf satuan cara Collins. Tahap kedua adalah penelusuran banjir dengan menggunakan metode level pool routing. Penelusuran banjir dilakukan untuk dua kondisi, yaitu kondisi lama (elevasi muka air awal +135,3m) dan kondisi baru (elevasi muka air awal +136,3m). Pemutakhiran debit banjir menunjukkan adanya kenaikan debit banjir ke Waduk Wonogiri sebesar 7,7% dan 3,6%, masing-masing untuk debit banjir kala ulang 60 dan 500 tahun, dibandingkan dengan studi Pradipta (2014). Hasil kajian menunjukkan bahwa Waduk Wonogiri rentan terhadap overtopping saat banjir kala ulang 500 tahun. Untuk mengantisipasi risiko tersebut, maka elevasi muka air waduk untuk pembukaan-penuh pintu pelimpah baru disarankan untuk diturunkan agar muka air waduk maksimum tidak melebihi extra flood water level.

People have used rainwater harvesting (RWH) technology for generations to a considerable extent in semi-arid and arid regions. In addition to meeting domestic needs, this technology can be utilized for agricultural purposes as well as soil and water conservation measures. Modeling the identification of the appropriate pond's location therefore becomes crucial. This study employs a Geo Information System (GIS) based multi-criteria analysis (MCA) approach and satellite rainfall data, Global Satellite Mapping of Precipitation (GSMaP) to determine the suitable locations for the ponds in a semi-arid area of Indonesia, Liliba watershed, Timor. The criteria for determining the location of the reservoir refer to the FAO and Indonesia's small ponds guideline. The watershed's biophysical characteristics and the socioeconomic situation were taken into consideration when selecting the site. According our statistical analysis, the correlation coefficient results of satellite daily precipitation were weak and moderate, but the results were strong and extremely strong for longer time scales (monthly). Our analysis shows that about 13% of the entire stream system is not suitable for ponds, whereas areas that are both good suitability and excellent suitability for ponds make up 24% and 3% of the total stream system. 61% of the locations are partially suited. The results are then verified against simple field observations. Our analysis suggests that there are 13 locations suitable for pond construction. The combination of geospatial data, GIS, a multi-criteria analysis, and a field survey proved effective for the RWH site selection in a semi-arid region with limited data, especially on the first and second order streams.

In Sleman, the Regional Water Company (PDAM) provides clean water to the community and charges a tariff for each cubic meter of water sold to customers. According to the Minister of Home Affairs Regulation No. 71 of 2016 states, PDAM tariffs requiring an annual review in November. The most recent tariff was set by PDAM Sleman in 2016, therefore, a recalculation is required. In addition, there is a need to analyze the tariff acceptance from the service provider, and service recipient’s point of view. In this study, the calculation tariff method utilized a formula based on the Minister of Home Affairs Regulation No. 71 of 2016. Meanwhile, the acceptance analysis from profit point of view conducted by calculating the projection of water sales revenue, profit to earning assets ratio, and customer willingness to pay (WTP). Furthermore, revenue projections were obtained by multiplying tariffs with the water sold volume, while the WTP projection is obtained using the inflation method, based on the PDAM Sleman customers’ wTP, from the 2007’s research. PDAM Sleman tariffs based on calculations resulted in low tariffs of IDR3727.48, basic tariffs of IDR4659.36, and full rate of IDR9460.17. Based on the WTP analysis, the tariffs are feasible from the service recipient’s (PDAM customers) point of view, because this is affordable by customers, for the average water consumption. However, from the service provider’s (PDAM Sleman) point of view, the tariffs are not feasible a 0.31% profit ratio is much lower, compared to the 10% profit ratio. Therefore, tariff adjustments are required to increase profits. These strategies include determining tariffs based on consumption blocks alone, without breaking down based on customer group categories and adjusting the second and third consumption blocks’ rate.

Generally, the condition of the rivers in Indonesia are alluvial rivers which had meanders, where the change in the river bed topography often occur. One of the parameters associated with changes in the river bed topography is bed-shear velocity, or Reynolds stress. The bed-shear velocity can be calculated by the Reynolds stress distribution method and the Clauser method which commonly used in straight channels. In fact, on natural channel there is a curve and even a meandering channel. With more complex flow conditions, the use of the Clauser method in curved channels can be questioned, is it still accurate or not. In this paper, both methods will be discussed by comparing the measurement data in the laboratory using 180 curved channel with flat bed. The results of data analysis show that the use of these two methods in curved channels produces an average difference of around 19.81%, where the Clauser method gives greater results and better tendencies. Apart from the differences in the results given, it can be said that the Clauser method as well as the Reynolds stress distribution method can still be used to calculate the bed-shear velocity in the curved channel.

In September 2018, there was an earthquake followed by liquefaction which caused damage to thousands of houses and infrastructure in Central Sulawesi Province, Indonesia. Liquefaction in Central Sulawesi has the potential to recur, so identifying potential liquefaction in areas that have occurred is essential. The objective of this research is to compare the results of determining liquefaction potential based on geotechnical and geophysical data. Based on the peak ground acceleration earthquake value, it shows that the liquefaction potential obtained in Mpanau is resemblant. The simulation will be conducted using Settle3 software based on methods, then the values of Cyclic Resistance Ratio (CRR) and Cyclic Stress Ratio (CSR) will be compared based on existing Multi-Channel Analysis of Surface Waves (MASW) data. MASW needs to be considered in the way of potential identification because it is advantageous. This Research uses MASW data where liquefaction flow and damage do not occur in Mpanau area even though the potential is quite significant. The result of this research shows that at distinct points of the SPT, MASW and the 7.5 Mw earthquake resulted in potential liquefaction still present in several soil layers, especially in the Gumbasa canal. It is necessary to repair and countermeasure to prevent liquefaction from disrupting the irrigation system's performance.

The development of the Dadahup Swamp irrigation area, as one of the food estate program locations, focuses on agriculture for rice cultivation. Besides rice, corn is also included as a food staple. Corn can be used as an alternative crop for farmers in case of rice crop failure during the dry season. Therefore, it is necessary to identify land characteristics for corn cultivation. In this study, land suitability analysis for corn used the FAO method based on eleven characteristic land parameters, including temperature, water availability, oxygen availability, root media, peat thickness, cation-exchange capacity, base saturation, pH H2O, soil organic carbon, toxicity and sulfidic hazard displayed on a map using QGIS. The results showed that seven parameters were very suitable for land use for corn, including water availability, oxygen availability, root media, peat thickness, cation-exchange capacity, pH H2O, soil organic carbon, and toxicity. Besides that, two parameters were marginally suitable for corn cultivation:temperature and base saturation. However, two parameters wereunsuitable for corn cultivation: water availability and sulfidic hazard. It was caused by rainfall with an average rainfall of 2245 mm/year and the depth of pyrite was found lower than 75 cm from the topsoil.The recommendations to make the land suitable for corn cultivation are good drainage system planning, leaching acid sulphate soil, liming and organic fertilizer application. The impact of this study is that it can be useful in designing corn cultivation so that it contributes to the food estate program.

On September 28, 2018, liquefaction in Sibalaya damaged irrigation canals and hit 51.2 hectares fields and roads. This phenomenon was triggered by an earthquake of magnitude 7.5 that shook Sigi Regency, Central Sulawesi Province. As an increase in soil pore water pressure is one of the causes of liquefaction, the pore water pressure ratio (ru) at the study site was analyzed. Then, this figure is used as a point of reference to determine the liquefaction potential. Standard Penetration Test (SPT) data and laboratory tests from four boreholes resulting from soil investigations in 2021 with a maximum depth of 20 meters were utilized in this study, along with microtremor data down to the depth of bedrock from test results in 2023. Based on the data, the liquefaction potential was assessed using the one-dimensional nonlinear site response approach, the GQ/H + PWP model, and the DEEPSOIL V.7 program. At multiple layers of boreholes, ru is more than or equal to 0.8, indicating that the Sibalaya liquefaction flow area is still susceptible to liquefaction.

The short-duration-rainfall monitoring techniques have become important recently due to the high demand for disaster risk miti­gation. Such techniques produce important information on the rainfall intensity during heavy rainfall in the form of snake line. At the same time, use of X-Band Multi-Parameter Radar (XMP Radar) in rainfall monitoring has increased significantly be­cause of its capacity to cover wide area. An assessment on the snake line performance that was developed based on XMP Radar and ground rainfall monitoring instrument (i.e. Automatic Rainfall Recorder or ARR) has been applied to Mt. Merapi area, Java, Indonesia. Selected rainfall data of November-December 2018 were examined. The assessment used a single pixel of radar data at the location of the ARR. The result shows that rainfall data obtained from XMP Radar are lower than those from ARR. The computed snake line obtained from XMP Radar differs from that from ARR data. The XMP Radar underestimates the warning level by about two level out of four.

Rainfall data is the main parameter to design drainage channel. The accuracy of rainfall data determines the accuracy of peak discharge estimation that is used for designing the drainage channel for flood mitigation purpose. The previous study presented that uncertainty of peak discharge is associated with the uncertainty of rainfall distribution and uncertainty of water holding capacity. The main purpose of this study is for understanding the sensitivity of rainfall data by comparing the estimated cost to construct drainage channel based on different values of peak discharges using two different rainfall data set which one rainfall data is created by considering 10% uncertainty of rainfall distribution. This study area is located on Plampang, Sumbawa Besar, West Nusa Tenggara. Results showed that the total cost to construct drainage channel increased by 15% if considering 10% uncertainty of rainfall.

* Corresponding author radianta@ugm.ac.id ABSTRACT Local scour due to tsunami is damaging especially on shallow foundation. Although relatively in a short duration, tsunami attack may scour material around buildings that led to destruction. A number of formulae on local scouring due to flood and tsunami have been available. The local scouring pattern and depth produced by tsunami may be affected by tsunami duration and tsunami surge Froude number and hence different to that resulted by flood which normally have much longer duration and lower Froude number. The research used a relatively short flume to create short duration tsunami surge that run-up on 1:20 beach slope and hit a vertical cylinder on land. Both the pattern and the depth of local scouring around the cylinder were observed and the results were compared with similar research but with different tsunami surge characteristic. It was shown that the maximum scour depth was significantly deeper than the final scour depth. When compared with other experimental study of local scour due to tsunami, the present local scour maximum depth seemed to be slightly less. This could have been caused by the relatively short duration of the present experiment. It was also found that the sidewall effect was insignificant when the ratio of cylinder diameter to the flume width was less then approximately 0.15.

The overflowing discharge of Bogowonto River in Purworejo Regency, Central Java flooded the surrounding area during the rainy season. A huge amount of losses such as damage of infrastructures, housing, and agricultural area occurs every year. This research mainly aims to develop flood hazard map and study the characteristics of flood in the study area. There are two main analysis; hydrologic and hydraulic, to model a flood event. Hydrologic and hydraulic modelling of flood based on 20 and 50- years return period hydrograph along the river geometryis done using the latest HEC program namely HEC- HMS 4.1 and HECRAS 5.0. Also, ArcGIS 10.3 is used as a terrain pre-processor and post-processor for hazard mapping. The results of this research are flood hazard maps for 20 and 50 years flood and its comparison to the recent major flood events. Flood inundation modelled covered an area of 993.77 Ha and 1,175.86 Ha, with maximum discharge calculated at Boro Weir as starting point are 1206.2 m3/s and 1,397.3 m3/s for 20 and 50 years flood case, respectively.

The study was aimed at identifying the learners' vocabulary learning strategies as they were engaged in tasks assigned along the SAMR model. A class of EFL learners was taught vocabulary with the assignments following SAMR. The model led them through four stages: substitution, augmentation, modification, and redefinition. The results showed that the learners increasingly used digital technology to accomplish their tasks. Their strategies were relatively more diverse, too. The metacognitive and social strategies, however, did not emerge substantially in their report.

An autonomous learning attitude is crucial in determining the successful completion of an online program. Such an attitude is not always easy. Students in online programs need to strike a balance between online studies tasks and their other work, maintain motivation, and consistently follow all the stages of the program. It remains to be seen whether these attitudes prevail in some Indonesian MOOC (Massive Open Online Course) students. This paper was a descriptive sketch of learning autonomy among thirty-seven students of an Indonesian MOOC. Only a small percentage of students was genuinely autonomous, while most were not, and experience difficulty in completing the MOOC program. The study found a correlation between autonomy and academic achievement, but did not demonstrate a cause-effect relationship.

This article argues for the use of a cooperative listening technique and describes the steps involved in using this approach. The author describes a five-step procedure for teaching listening strategies, and then uses his own experience to show how this approach can help learners develop listening comprehension. The author also discusses his perspectives on potential issues of this cooperative listening approach.

One of the challenges in using Manning’s equation lies in accurately determining Manning’s roughness coefficient, especially due to sediment transport. The condition of sediment transport within a specific section of a river can be in equilibrium, meaning that the amount of sediment entering and exiting the segment is balanced or it can be in non-equilibrium, where there is an imbalance between the sediment entering and leaving the segment. Experiments were carried out in the laboratory to simulate both transport conditions, one involving sediment feeding (equilibrium condition) and the other without sediment feeding (non-equilibrium condition). A total of 180 mean velocity profiles were measured using an acoustic doppler velocimeter (ADV) in fixed and movable bed flows. The present experiment was combined with theoretical approaches to evaluate Manning’s coefficient in open channels under sediment transport-flow conditions and reach conclusive results. The shape of the velocity profile, u/U, for flows over a movable bed with sediment feeding is “slender” compared to those without sediment feeding. The presence of sediment transport affects the shape of the velocity profile, especially in the inner region, influencing Manning's roughness coefficient. This coefficient can be determined from two-point velocity measurements at z/H = 0.1 and 0.2 for fixed and movable bed flows with and without sediment feeding, respectively. On average, sediment feeding increases the coefficient by 19% compared to the non-sediment feeding case. [ABSTRACT FROM AUTHOR]

This experimental study is to determine the velocity vector and flow contours in a reservoir with a bottom outlet. Velocity vector flow and contour characteristics are studied by making laboratory studies using acrylic models. The model combines the first pond as a constant head tank and the second pond as a reservoir with a hole at the bottom or bottom outlet. Particle Image Velocimetry (PIV) is an optical visualization qualitative and quantitative technique for measuring the velocity of a fluid by measuring the slight movement of a particle or object in a particular fluid area by observing the location of the tracer particle used in education and research detail. The PIV method relies on recording particle images and measuring object markers (tracer particles) distribution at several locations to measure instantaneous velocity and different phases, velocity fluctuations, and accelerations well in fluid flow. Brown shellac was chosen and used for tracer particles after several experiments using other seeding materials such as white shellack, glitter, and glycerine. The brown shellack is crushed manually, filtered to pass sieve 30 (0.5 mm), and retained on sieve 50 (0.3 mm). The recorded image file is then read and processed to obtain the magnitude and direction of velocity at the tracer particle locations captured in the image recording. The experiment was carried out by running the water flow from the constant head to the reservoir model by giving tracer particles of brown shellac. Experiments produce the most significant velocity around the bottom outlet is 265 cm/s or 2.65 m/s. [ABSTRACT FROM AUTHOR]

As character education is gaining currency, some institutions have started to incorporate character education into its instructional practices. However, this is not an easy task. Limited hours of contact and teachers' insufficient know-how of teaching and evaluating students' characters have hampered the efforts. This paper reports a small effort to shape students' honesty through self-scoring techniques. An intact class of 19 students who were taking a content course were instructed to self-score their own works in two different tests. Their scores were then compared to the lecturer's scoring. It was found that the students tend to be honest when the test was not weighted substantively, but increasingly over-rated themselves on a high-stake test. The paper then discusses the potential and possible weaknesses of self-scoring technique as a means of cultivating honesty.

Sediment transport in a river segment can be in equilibrium or non-equilibrium, depending on the amount of sediment entering and leaving the segment. The sediment transport flow can cause the riverbed to either remain stable or become unstable, resulting in either degradation or aggradation of the riverbed. This study evaluates the effect of equilibrium and non-equilibrium sediment transport on flow characteristics such as velocity, turbulence intensity, and Reynolds shear stress. Experiments were conducted with (SF) and without sediment feeding (NSF) to represent the laboratory's two sediment transport conditions. One hundred and twenty mean velocity and turbulence profiles were measured using an Acoustic Doppler Velocimeter in movable bed flows with sediment transport. The flow velocity profile with sediment feeding tends to become more slender than that without sediment feeding. The velocity profile in the inner region decreases and increases in the outer region. The friction velocity, u*, and the integration constant of the logarithmic law, Br, which decreases closer to the channel side wall, show a more pronounced trend for the data with sediment feeding. The data on turbulence intensities of u'/u*, v'/u*, w'/u*, follows an exponential law pattern; clear distinctions are observed between flows with and without sediment feeding. The measurement of Reynolds shear stress -ufvf/u*² displays a linear trend of shear-stress distribution. The suppression of Reynolds shear stress is observed and is more pronounced closer to the channel bed (y/H < 0.15 - 0.2) and towards the channel side wall, especially for the flow with sediment feeding. [ABSTRACT FROM AUTHOR]

The Wonogiri Reservoir is a multipurpose reservoir at the Upper Bengawan Solo Watershed, primarily designed to serve as a flood control system. However, there is no accurate estimation of the inflow into the reservoir due to the limited availability of hydrological stations. Observations showed only four out of ten unit hydrographs of the Wonogiri Reservoir watershed. Therefore, this study was conducted to apply an integrated similarity-based approach for designing unit hydrographs in ungauged catchments. The process involved evaluating the integrated similarity between pairs of gauged-ungauged catchments using hydrologic and physical property parameters. This led to the selection of the donor or gauged catchment with the highest similarity score to develop the unit hydrograph for the ungauged catchments. The developed UHs were further applied to estimate the reservoir inflow for the December 25, 2007, flood event. The results showed that the computed peak discharge was 10.9% lower than a previous study. Subsequently, the HEC-HMS simulation model was used to project the updated design flood hydrographs to the reservoir. The design rainfall was derived from automatic rainfall recorder (ARR) and PERSIANN satellite-based data. The ARR data showed that the extreme rainfall duration was 5 hours while satellite data indicated 6 hours. The application of the ARR 5-hour duration to the updated flood hydrographs led to a peak discharge of 5123 m³ s-1, 7041 m³ s-1, and 10,370 m³ s-1 for the 60-year, 500-year, and PMF floods respectively in line with the flood design criteria of Wonogiri Reservoir. These estimates were observed to be significantly higher than the 1982 design floods which were 4000 m³ s-1, 5100 m³ s-1, and 9600 m³ s-1 respectively. This updated flood control design was important to renew the operation rule of the Wonogiri reservoir during flood periods. [ABSTRACT FROM AUTHOR]