Project’s cost is one of important components in project achievement. Because of the uniqueness of construction projects, cost estimation always differs from project to project. The rate of cost components always change over time make difficult to forecast the cost for the upcoming project. The cost component consists of many influencing variables where there is interrelationship each other affecting to the total project cost. This paper objective is to develop a cost prediction model to assist the project planners in cost estimation for future projects. System dynamic is one of the appropriate methods to analyse system behaviour with interrelationship referring to the historic data, so it is able to predict the future project. Developing the model, primary and secondary data are collected from previous studies, interview with the government planner and survey in Malang Regency. The model simulation is Brick work unit with its components. Data from last thirteen years are used to verify and validate the developed model by causal loop diagram as a basic method in system dynamic. The finding showed that the model is closed to real condition through the validation mechanism. The developed system is useful in decision making of budget planning based on work quantity.

Project cost is one of the constraints in the achievement of a construction project. Limitation on projects financing require more realistic and efficient cost analysis in preparation of project.  Due to changes in projects planning over time, it is usually difficult to predict the future project cost. So, we need an integrated system and give an efficiency for the planner. Project cost consists of cost components which is there are an interrelationship each other’s and influencing the overall cost of the project. The approach using system dynamic is one of the best solutions to identify the causal relationship between cost components by using software tools Ventana Simulation (Vensim) to facilitate the identification of causal relationship (causatic diagram) and mathematical equations between variables in stock flow diagram. The results of system dynamic approach show that the simulation model can be used to predict/ estimate the project’s cost in the coming years. Verification and validation of simulation model is eligible based on the value of means comparison, E1 = 0.32% < 5% and % error variance, E2 = 3.19% < 30% so the developed model can be done scenarios for changes that occur on the system according to the user needs.

Surface waters give a plentiful supply of waters ready to be utilized for residence, farmland, fishery, industry, and electric generating machine, and most importantly, to deal with the problem of water scarcity (crisis). Rain is one of the hydrological cycles that help to preserve groundwater (shallow groundwater). During the rainy season, most waters go directly to the river and the sea without processing, creating inundations and flood in some places. Water resources, however, begin to lose their supporting capacity. Water supply is no longer balanced with the demand that starts to bulge up excessively. This disrupted balance is indicated by many critical lands that are less productive and incapable of absorbing waters to the ground. Considering this outline, the implementation of environmentally friendly infiltration wells can be a strategic option to solve the water balance issue. Some alternatives of infiltration wells are proposed as the solution to the problem that this research deals with. It is estimated that these wells can reduce 10%-15% of surface runoff rate in Lowokwaru District of Malang City, especially around Soekarno-Hatta Street that always leaves massive water puddle, especially during the rainy season. This research gives the relevant institutions and user community information about drainage construction, drainage network, and land use above drainage network. Through this information, it is expected that the follow-up can be given efficiently to produce an optimum and effective drainage network. Community participation, therefore, is needed to maintain the benefits of alternative infiltration wells to ensure their sustainability in the future.

Global Warming has had an impact on climate change, which has caused disturbance to the availability of surface water and the change in the allocation of irrigation water for agriculture. The agricultural sector is a sector that is vulnerable to climate change. Therefore, the provision of irrigation water must be adapted to climate change so that the supply of irrigation water for agricultural land is well maintained to increase food production. The method used in completing this research is the descriptive method, involving observations during the rainy season, first dry season, and second dry season, soil tests at the research site, and disseminating improvements to the provision of irrigation water, so that irrigation water is more efficient in usage and distributed at the right time at the start of the rainy season, first dry season, and second dry season. In distributing questionnaires and providing understanding of the occurrences of climate change, almost all stakeholders have understood that the provision of irrigation water must be refined and adapted to climate change. Dissemination has been carried out to all stakeholders including the government and relevant agencies. The government promises to change the irrigation water regulation policy in order to maintain food productivity.

Bendung Wae Cepang adalah salah satu bendung yang ada di Kabupaten Manggarai, terletak di Desa Nangka Kecamatan Satarmese dan bendung inilah yang melayani lahan pertanian desa Nangka. Perlu di ketahui bahwa hampir sebagian besar penduduknya berprofesi sebagai petani sawah, dan menggantungkan hidup dari hasil sawah, sangat di harapkan optimalisasi fungsi bangunan bendung, sehingga dapat menunjang dan memaksimalkan hasil pertanian. Bendung Wae Cepang seharusnya mampu mengairi seluruh lahan tersebut apabila fungsinya lebih di optimalkan kembali. Untuk di ketahui Bendung Wae cepang mempunyai masalah yang serius yaitu masalah merembesnya air melewati bawah tubuh bendung. Sehingga menyebabkan air yang sebenarnya harus di alirkan ke area persawahan harus terbuang percuma dan tidak di manfaatkan dengan baik, untuk itu perlu dilakukan desain ulang bendung untuk peningkatan debit air irigasi desa Nangka Kecamatan Satarmese Kabupaten Manggarai. Berdasarkan hasil analisa hidrologi didapat dimensi bendung : tinggi bendung adalah 2.1 meter, tinggi muka air banjir adalah 4.599 meter, lebar mercu bendung adalah 5,9 meter, tipe kolam olakan adalah tipe cekung dengan jari jari 7,06 meter. Berdasarkan hasil analisa stabilitas bendung, maka konstruksi ini aman terhadap gaya guling geser dan daya dukung tanah aman terhadap up lift, baik di tinjau pada kondisi air normal danpa ataupun dengan terjadi gempa dengan ketentuan SF > 1.5 untuk kondisi tanpa gempa dan SF > 1.25 untuk kondisi dengan gempa.