Peningkatan Efisiensi irigasi dapat dilakukan pada saat penyaluran (conveyance), distribusi maupun aplikasi. Kehilangan air dalam bentuk evaporasi, bocoran, rembesan, perkolasi maupun air yang terbuang perlu ditekan sekecil mungkin. Tujuan penelitian ini adalah mengkaji perkolasi lahan sawah yang dilengkapi dengan lapisan kedap buatan dalam kerangka irigasi hemat air dan peningkatan efisiensi. Lapisan kedap dibuat dengan cara memadatkan lapisan tanah di bawah lapisan olah dengan menggunakan soil stamper dan baby roller. Ketebalan lapisan kedap diperoleh sekitar 14 cm dan kekerasan maksimumnya berkisar antara 9.41 kg/cm2 – 13.28 kg/cm2. Besar perkolasi diperoleh berkisar antara 7.9 sampai 21.3 cm/hari. Perkolasi yang relative lebih kecil diperoleh dari lahan yang dipadatkan dengan baby roller. Tetapi perkolasi yang diperoleh ini masih terlalu besar untuk lahan sawah yang hanya sekitar 4 mm/hari. Hal ini mungkin disebabkan oleh kondisi tanah dari lahan tersebut yang mempunyai perkolasi sangat tinggi (508.8 cm/hari).

No abstract

The Aesesa Flores (AF) watershed has an important role for the community in the district of Ngada and Nagekeo, East Nusa Tenggara Province of Indonesia. However, in recent years, over exploitation of natural resources in the AF watershed has caused severe land degradation in the region. This study analyzed the carrying capacity of the AF watershed. The assessment of the AF watershed carrying capacity in this study was done according to the Indonesian Ministry of Forestry Regulation Number P.61/2014 that regulates the monitoring and evaluation of watershed management. The main objectives of this study were to assess the carrying capacity of the AF watershed, and evaluate the suitability of the aforementioned regulation to its condition. The results of carrying capacity analysis showed that the upstream region of the AF watershed was categorized to have a low carrying capacity condition, while both the middle and downstream region of the watershed were categorized to have a moderate carrying capacity condition. These results indicated that there was a need to prioritize the rehabilitation and land management in the upstream region of the AF watershed, in order to improve its condition.

Total water demand at non industrial and industrial region in Cilegon is increasing. With its water production capacity of 2,000 l/s, PT Krakatau Tirta Industri (KTI) cannot fulfill the amount number of demand from the industrial and domestic sectors at Cilegon. To cover the shortage of water supply of ±600 l/s, PT KTI requires taking water from Cipasauran Watershed. The objective of this study was to analyze river discharge of Cipasauran Watershed using SWAT model. Input data such as soil characteristics, climate data, landuse, and hydrology data at the area of the watershed were gathered and put at the data input file. In SWAT simulation, 4 processes were done, i.e. watershed delineation, hydrological response unit (HRU) forming, data process and SWAT simulation, and visualization process. The result showed that the daily and monthly calibration process crossed 84% and 83% with the 95PPU area, with daily and monthly p-factor value of 0.84 and 0.83. Thus, calibrated model result was valid, though R 2 and NS value were not satisfied. Using the validated SWAT model, the daily discharge in Cipasauran Watershed was about 0-3.309 m 3 /s, whereas the monthly discharge was 0.648-3.266 m 3 /s. This showed that daily and monthly PT KTI's water demand of 0.6 m 3 /s were fulfilled about 98.22% and 100%. Within the future time, the SWAT model could be potentially used as an assessment for predictive scenarios. However, to gain optimum results, well-observed and precise data is highly required, especially for such calibrations and validations.

Land-use changes from forest to other use will affect watershed hydrological system that lead to water availability in Leitimur Peninsula watershed, Ambon Island. It aims to analyze sustainability index and sensitive attribute of watershed management and to design watershed management model in supporting sustainability of water resources in Leitimur Peninsula. The analysis applies the Multidimensional Scaling (MDS) model and the dynamic model (Stella). The findings signifies that multidimensional sustainability status is 50.97% indicating quite sustainable, while the best management model is by performing land and forest rehabilitation (LFR) and agricultural extensification through agro-forestry system.