Increased population, directly proportional to the increase in clean water needs. It also affects the availability of clean water both for current needs and for future time. To ensure that the availability of clean water can meet the needs of 2030, a study is needed to find out how much availability of clean water in 2030 and what needs are needed. To find out, a proper calculation method is needed. In this study, the availability of clean water in 2030 was calculated using the geometry method. Before calculating it, data on clean water availability was needed in the previous few years to find out the average growth of water availability which subsequently using geometry methods can be known to the availability of water by 2030. The results of the calculation showed that the availability of clean water in 2030 was 336.62 liters/second. Meanwhile, to calculate the need for clean water calculated using data on average clean water requirements today was then analyzed by the estimated population in 2030. The result was, the need for clean water in 2030 with the level of population at that time was 668,7756 liters/second. It can be concluded, the need for clean water in 2030 is greater than the availability of clean water. Therefore, looking for other important clean water sources is planned as early as possible so that water needs by 2030 are still fulfilled.

Countermeasures of community-based lake sediments are directed at maintaining the dynamic balance of Lake Batur, Beratan Lake, Lake Buyan and Lake Tamblingan. Sedimentation process of this lake is triggered by the pattern of management of agricultural land on the edge of the lake is less attention to aspects of soil and water conservation. The purpose of this research is; (1) to obtain a community-based sedimentation prevention model, (2) Mapping Land management on the edge of the lake, (3) erosion control strategy at the edge of the lake. This research is field experiment and surpei research, sampling is done by purposive sampling at Batur Lake 20 samples, Beratan Lake 16 samples, Lake Buyan 16 samples and Danau Tamblingan 12 Sampel. The socio-economic support data of the community was determined by 180 respondents in cluster sampling. Interviews and questionnaires are closed questions on a conventional scale. Characteristics of the lake were analyzed descriptive statistics using   SPSS analysis tool. Land mapping is done by GPS method with GIS device. Predict erosion using the Universal Soil Loss Equation (USLE) Model while for sedimentation using the Stanford Sediment model. Data analysis to find out the model of development of sedimentation rate in lake due to erosion that happened, done by non linear regreresi analysis. The results of the analysis are tested on both sides with 95% confidence level on sediment data that is modeled whether or not significant effect

Erosion control in Lake Batur area is community-based directed to maintain lake balance. The aims of this research is; (1) to obtain a community-based erosion control model, (2) to analyze the role of communities in the application of land management models. (3) Analyzing other plant species in collaboration with the arrangement model . (4) Analyzing the impact of terraces blooming against sedimentation. This research is field experiments and surveys, and the sampling was conducted by purposive sampling with 64 samples. The socio-economic support data of the community was determined by 180 respondents by cluster sampling. Interviews and questionnaires were conducted through closed questions on a conventional scale. The characteristics of the lake were analyzed statistically and descriptively by using the SPSS tool. Land mapping was conducted by GPS method with GIS device. Prediction of erosion was by using USLE Model, while sedimentation was measured by the Stanford Sediment model. The analysis shows that the increase of settlement is averagely of 115,85%, plantation is 245,50% and the sedimentation level is 1,017,93 m3 / year. Conclusions and outcomes were in the form of community-based terracing model that collaborate with elephant grass and vetiveria plants.

Erosion control in the community-based Lake Batur area is directed to maintain the balance of Lake Batur. Erosion triggered by the pattern of management of agricultural lands less attention to aspects of soil and water conservation. The purpose of this research is; (1) to obtain a community-based erosion control model, (2) Land management Mapping on the edge of the lake, (3) erosion control strategy at the edge of the lake. This research field experiment and surpei, sampling is done by purposive sampling with amount of 64 sample. The socio-economic support data of the community was determined by 180 respondents in cluster sampling. Interviews and questionnaires are closed questions on a conventional scale. The characteristics of the lake were analyzed descriptive statistics using the SPSS tool. Land mapping is done by GPS method with GIS device. Predict erosion using the Universal Soil Loss Equation (USLE) Model, for sedimentation using the Stanford Sediment model. The analysis of the rate due to erosion, done by non linear regression analysis. The analysis shows that the settlement has an average of 115,85%, plantation 245,50% and sedimentation level 1,017,93 m3 / year. Sedimentation was tested on both sides with a 95% confidence level on the modeled sediment data. Conclusions to tackle erosion using a community-based Terracing Mekar land arrangement model that collaborates with elephant grass and vetiveria.

Erosion control in Lake Batur area is community-based directed to maintain lake balance. The aims of this research is: 1) to obtain a community-based erosion control model, 2) to analyze the role of communities in the application of land management models, 3) to analyze other plant species in collaboration with the arrangement model, and 4) to analyze the impact of terraces blooming against sedimentation. This research is field experiments and surveys, and the sampling was conducted by purposive sampling with 64 samples. The socio-economic support data of the community was determined by 180 respondents by cluster sampling. Interviews and questionnaires were conducted through closed questions on a conventional scale. The characteristics of the lake were analyzed statistically and descriptively by using the SPSS tool. Land mapping was conducted by GPS method with GIS device. Prediction of erosion was by using USLE Model, while sedimentation was measured by the Stanford Sediment model. The analysis shows that the increase of settlement is averagely of 115.85%, plantation is 245.50% and the sedimentation level is 1,017,93 m3/year. Conclusions and outcomes were in the form of community-based terracing model that collaborate with elephant grass and vetiveria plants.