Developed watershed classification index determining management priority level based on watershed carrying capacity

Watershed classification index is important in terms of determining watershed management priority level based on its carrying capacity score whereby currently watershed is classified into two indexes which are “to be maintained” if the carrying capacity score is below 100 and “to be restored” if it is above 100. This index fails to capture existing condition where there are watersheds with carrying capacity score in between 90 and 110. The purpose of this paper is to propose developed watershed classification index to determine management priority level based on watershed carrying capacity score. The method used to develop the watershed classification index is Classification Interval approach. The analysis is resulting in rigorous management priority level based on developed watershed classification index which is 50 < carrying capacity ≤ 90 as Priority 3 (watershed indexed as “to be maintained”), 90 < carrying capacity ≤ 110 as Priority 2 (watershed indexed as “to be improved”) and 110 < carrying capacity ≤ 150 as Priority 1 (watershed indexed as “to be restored”). Therefore, the correct management priority level for Gangsa Watershed that has carrying capacity of 106 is Priority 2

PENILAIAN RISIKO BENDUNGAN SAGULING DENGAN METODE TRADISIONAL, METODE POHON KEJADIAN DAN METODE MODIFIKASI ICOLD

The role of dam infrastructure must be ensured from management and maintenance through good operational and maintenance provisions as to maintain level of service provision, extend life of productive assets and reduce risk of dam failure. Dam risk assessment can be used to prioritize dams based on risks. Risk assessment consists of risk analysis and risk evaluation. Purpose of this study is to conduct a risk assessment on Saguling Dam using traditional methods, event tree methods and ICOLD modification method to get an overview safety condition Saguling Dam. In conducting risk evaluation for ICOLD modification method, evaluate by comparing value of risk index to risk class. results of the risk identification analysis of this study that risk assessment using traditional method shows that risk of the Saguling Dam is unacceptable because this method does not describe each possibility in detail. Risk assessment using the event tree method shows that the risk of the Saguling Dam is acceptable. Risk assessment using the modified ICOLD method shows that the Saguling Dam belongs to category of Dam with moderate risk

INTERPRETASI TEKANAN AIR PORI SEBAGAI DASAR PEMELIHARAAN PIEZOMETER DI BENDUNGAN SERMO

Pore water pressure readings (piezometer readings) produce data that must be interpreted before being used for further analysis. This process is very influential on the results of the analysis because in the piezometer reading there is the possibility of anomalies due to potential delays or lags or errors in readings. The purpose and objective of this research is to provide an alternative approach to dam safety instrumentation inventory in order to be able to arrange maintenance work properly, effective and efficient, in conditions of limited budget can be used as a standard in making decisions in prioritizing piezometer maintenance. Several piezometer data processing methods can use techniques, including : interpretation of pore water pressure patterns; correlation simulation of pore pressure values and flow line plots. The results of the research on the piezometer at the Sermo Dam can be distinguished between conditions that have good pore water pressure readings and the opposite condition, with a ratio of 71,43% and 28,57%

PREDIKSI LAJU EROSI PADA DAERAH TANGKAPAN AIR BENDUNGAN DENGAN METODE USLE (STUDI KASUS : BENDUNGAN TITAB)

Erosion is a serious problem in watershed management. The Saba watershed is a water catchment area at the Titab Dam in Buleleng Regency, Bali Province. The existence of the Titab Dam is accompanied by the development of activities of the surrounding community, both tourism, economic and daily activities. Unfortunately, this activity in the future will have a negative impact on the condition of the dam so that it poses a risk. This study aims to determine the amount of sediment inflow with land erosion approach at the Titab Dam using the USLE (Universal Soil Loss Equation) method. Erosion rate prediction was carried out using the USLE method and with the help of ArcGIS 10.8 software. From the results of the analysis, it was found that in the Titab Dam catchment area, only 3 classes were obtained. The results of the calculation of the erosion rate using the USLE method showed that the magnitude of the erosion was 439,962 tons/year or 53.05 tons/ha/year. In addition, the most influential factors on the rate of erosion are the length and slope factors. In addition, land cover is also one of the most influential factors

The impact of water conservation using sedrainpond and infiltration wells on surface water quantities: a case study of the Pakopen micro watershed, Semarang District, Central Java, Indonesia

Due to the increasing amounts of surface runoff and land degradation in watersheds, mitigation efforts need to be taken by adopting water conservation technologies to reduce flooding and surface runoff. The purpose of this research is to study the impact of sedrainpond (SDP) and infiltration well technology procurement on surface water in order to mitigate flood disasters downstream. The method approach is carried out by measuring the field discharge, collecting rainfall data and analysing the data using ArcView GIS and Microsoft Excel. The measured discharge in the study was 1170.9 L/s. The study applies 1819 units of SDP technologies with a diameter of 1 m, a depth of 2.5 m and a total storage volume of 3573.11 m3, and 340 units of infiltration wells with a diameter of 1 m, a depth of 2 m and a total storage volume of 533.65 m3. For scenario 1, where the water contained in the well is drained in one day, the flood discharge can be reduced to 986 L/s, along with a flow rate decrease of 184.9 L/s (15.79%). While for scenario 2, where the water contained in the well is drained in two days, the flood discharge can be reduced to 1001.6 L/s with a flow rate decrease of 184.9 L/s (14.46%)

EVALUASI DEBIT REMBESAN DARI DATA BACAAN V-NOTCH PADA BENDUNGAN BENEL

The Benel Dam, one of the dams in Bali, is an already operational dam, so it necessary to monitor the behavior of the dam body to be able to find out as early as possible if an anomaly occurs, one of which is monitoring seepage discharge at the v-notch. The purpose of this study is to determine the fluctuation of seepage discharge and its correlation to the reservoir level, and to determine the safety of the seepage discharge that occurs. The evaluation of seepage discharge is carried out on reading data that is not influenced by rainfall, then compares it with the limits of the seepage acceptance criteria and seepage index. From the analysis results show the correlation between seepage discharge and reservoir level r = 0.2296 and after parsing the data, it is obtained for 2013, 2014, 2018 and 2019 data that the correlation level is moderate - very strong. The results of the parsing then selected data that is not affected by rainfall. The seepage discharge that occurs is still smaller than 0.14 liters/minute/meter, while the seepage index (QI) is greater than 1. In the seepage index analysis, it is necessary to use the seepage path length parameter that is appropriate or close to the actual condition

Analisis Penanganan Longsoran Pada Bangunan Pelimpah Bendungan Ciawi

The shallow landslide on the left slope of the Ciawi Dam spillway occurred in June 2020. The landslide occurred gradually and disrupted the progress of the dam construction. Therefore, this study aims to analyze the stability of the slope and determine the safe number of the slope then providing recommendations for proper handling. The method used in this study is the limit equilibrium method with the SLOPE/W geostudio program which is run in two methods of determining safety factor, Bishop and Fellenius/Ordinary. Based on the results of the stability analysis, the safety factor is 0.915 for Bishop method and 0.852 for Ordinary method. The first attempt at handling the slopes was to reduce the slope, but this effort did not provide a significant increase in the number of safety factor. The next handling is to use the reinforcement of 3 borepiles with a depth of 35 m, 40 m, and 45 m with a distance between the piles of 40 mm with a shear strength of 150 kN. This effort provides a safety factor number of 1.754 Bishop's method and 1.546 Ordinary’s method with the result that it meets the safety requirements of slope reinforcement.The shallow landslide on the left slope of the Ciawi Dam spillway occurred in June 2020. The landslide occurred gradually and disrupted the progress of the dam construction. Therefore, this study aims to analyze the stability of the slope and determine the safe number of the slope then providing recommendations for proper handling. The method used in this study is the limit equilibrium method with the SLOPE/W geostudio program which is run in two methods of determining safety factor, Bishop and Fellenius/Ordinary. Based on the results of the stability analysis, the safety factor is 0.915 for Bishop method and 0.852 for Ordinary method. The first attempt at handling the slopes was to reduce the slope, but this effort did not provide a significant increase in the number of safety factor. The next handling is to use the reinforcement of 3 borepiles with a depth of 35 m, 40 m, and 45 m with a distance between the piles of 40 mm with a shear strength of 150 kN. This effort provides a safety factor number of 1.754 Bishop's method and 1.546 Ordinary’s method with the result that it meets the safety requirements of slope reinforcement

Nilai Indeks Kesiapan Program Modernisasi Irigasi pada Daerah Irigasi Sucen Jawa Tengah

Modernization of irrigation systems plays a huge role in realizing a participatory irrigation management system oriented towards efficiency, effectivity, and sustainability of irrigation systems to support food and water security. This study aims to evaluate the modernization readiness of the Sucen Irrigation, referring to the five pillars of irrigation modernization as measured by the readiness index score (IKMI). The method used in this research is direct observation and interviews. The result from this study shows that Sucen Irrigation Area got a moderate category with a total score of 63.5 which the result for each pillar is 14.8 of the IKMI score for Water Availability, 17 for Irrigation Facilities and Infrastructure, 10.6 for the Irrigation Management System, 14.2 for Institutional Management, and 6.9 for the last pillar which is Human Resources Management. Therefore, the moderate category points to modernization should be postponed to improve the irrigation system within 1-2 years

Performance of Sumur Gendong (SeDrainPond) Technology on Harvesting Water and Sediment with Respect to Effective Rainy Days

Land degradation and climate change are reducing soil fertility and water availability in agricultural areas. So, agricultural production is reduced, which is detrimental to food security and farmers’ livelihoods. These problems must be mitigated together with farmers. The farmers-based technology called Sumur Gendong (SeDrainPond) technology has been used and its performance has been analysed, in order to give farmers a basis to determine farming strategy. The performance of Sumur Gendong in harvesting water and sediments in relation to effective rainy days has been studied for this paper. The fertility of the harvested sediment has been also analysed, and a suggestion has been proposed to improve it. The study has been carried out using a combination of field measurements and laboratory analyses on 10 (ten) test ponds with average diameter 1 m and depth between 2 and 2.5 m on 5 hectares of paddies. The volume of water harvested from the pond annually has been 567 m3 and the one of harvested sediment has been 344 kg. The fertility of the harvested sediment has been moderate across the study area, on the basis of the combined soil chemical propertie