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Watershed areas (watersheds are divided into upstream, middle and downstream areas. Upstream watersheds are characterized as conservation areas, have a higher drainage density and are areas with slopes of more than 15%, lower watersheds are characterized by areas with small slopes (less than 8%) to flat, in some places it is a flood or puddle area. Water management is determined by irrigation water structures. The middle watershed is a transition area between upstream and downstream. (Asdak, 1995). main, (1) vegetative method, (2) Mechanical method, (3) Chemical method (Arsyad, 2010). In watershed spatial planning, vegetative methods and mechanical methods are recommended There are several methods that can be used to prevent landslides in watershed areas, both upstream, middle and downstream, but what is highly recommended is the Vegetative method and cultivating these plants. [ABSTRACT FROM AUTHOR]

Erosion forecasting is a complex issue generated by numerous causes, the extent of which varies based on the unique area and conditions. Changes in rainfall, land cover, and watershed function are the primary causes of increased erosion. This study aims to scrutinize the actual and potential erosion in the mining area (MA), oil palm plantations (OPP), and watersheds reforestation (WR) in Asoloe, South Konawe, Indonesia. We utilized qualitative research methods and surveys with the USLE model. MA shares the highest actual erosion with 332.30 tons/ha/year, with an average erosion of 27.69 tons/ha/year from 2011 to 2022. Meanwhile, the potential erosion is 4747.19 tons/ha/year, with an average of 395.60 tons/ha/year. In terms of current conditions, 44.6% of rainfall engenders erosion with more than 0.5 t/ha and 33.9% with more than 1 t/ha. This study successfully demonstrates that for given location and area characteristics, high amounts of rainfall and changes in land function eminently affect soil erosion and that the potential erosion changes that occur in the Asoloe watershed every year are exceptionally influenced by changes in land use and land function. Therefore, some mitigation strategies and policies must be taken to reduce the risk of future erosion. [ABSTRACT FROM AUTHOR]

Integrated watershed management is a holistic and sustainable approach in managing water resources and the environment associated with river flow. One of the important aspects in integrated watershed management is to pay attention to the socio-economic aspects of the people living around the river. In many places in Indonesia, watershed bears a heavy burden due to its high population density and intensive utilization of natural resources, leading to environmental degradation and a decline in watershed conditions. On the other hand, the demands on watershed to support livelihood systems, including community activities and fisheries from upstream to downstream, coastal areas, and the sea, are substantial. The purpose of the study was to identify the socio-economic situation of the community and how to manage the watershed with the approach of the socio-economic aspects of the community. The method used was Qualitative analysis with observation, deep interview, and questionary. The purpose of the study was to identify the socio-economic situation of the community and how to manage the watershed with the approach of the socio-economic aspects of the community. The method used was Qualitative analysis with observation, deep interview, and questionary. The results showed that education level in the upstream area is higher than the downstream area. The level of education, employment, and community income can affect their attitudes and participation in watershed management activities. Communities who have higher education, jobs related to watersheds and coastal areas, and adequate income tend to be more active and aware of maintaining the sustainability of watersheds and coastal areas. [ABSTRACT FROM AUTHOR]

The agreement between meteorological data and societal perception is essential in supporting a robust policy making and its implementation. In humid tropic watersheds like Brantas, such consensus is important for water resources management and policies. This study exemplifies an effort to understand the long-term rainfall characteristics within the watershed and to build a common link among the differing data sources: CHIRPS rainfall satellite data, rain gauge data, and farmers perceptions. Six rainfall characteristics were derived using statistical measures from the scientific data and then were translated to a series of structured questionnaires given to small-scale farmers. A consensus matrix was built to examine the level of agreement among three data sources, supporting the spatial pattern of the meteorological data and farmers perception. Two rainfall attributes were classified with high agreement, four with moderate and one with low agreement. The agreements and discrepancies of rainfall characteristics were found in the study area. The discrepancies originated from the accuracy in translating scientific measurements to practical meanings for farmers, complexity of the farming system, the nature of phenomena in questions, and farmers' ability to record long-term climatic events. This study shows an implication that a combined approach to link scientific data and societal data is needed to support powerful climate policy making. [ABSTRACT FROM AUTHOR]

Natural disasters in Indonesia have become an annual cycle, an example is flooding. This study aims to determine the flood risk potential in the Mempawah watershed and the places likely to be flooded. The method used was a survey and interpretation of secondary data from topographic maps, Sentinel-2A images, and Digital Elevation Model images. Furthermore, the secondary data analysis used includes the Standardized Precipitation Index (SPI), Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Soil Adjusted Vegetation Index (SAVI), and Inverse Distance Weighted (IDW). The result showed that the Mempawah watershed has high, medium, and low flood risk potential. Areas with high flood potential have an area of 1,511,967 ha, those with medium potential were 2,606,778 ha, and the places with low potential were 12,644,034 ha. The changes in class user's accuracy results reached 90.909%, while those with no change were 83.333%. It was also discovered that when the satellite analysis was > 70%, it was regarded as good. This means that the accuracy of the interpretation results and flood change detection approach was also good. [ABSTRACT FROM AUTHOR]

Suspension flow into the upstream of volcano watershed is sensitive to land use. In Indonesia, a settlement is a form of land use in several volcanic landscapes. There is currently no detailed study on the suspension flow sediment from the settlement land use. The purpose of this study is to investigate the characteristics of the relationship between water and suspension flow discharge. The study was conducted through the measurements at a gully outlet that produced 747 suspension load data. For each rainfall event, suspension load measurements were made in the field, followed by laboratory analysis. Additionally, field surveys were used to determine the characteristics of settlement land use and the water flow into the gully system. According to the findings, the peak flow discharge corresponds to the peak suspension discharge, the peak flow discharge comes before the peak suspension discharge, and the peak flow discharge happens after the peak suspension discharge. The average time lag between initial rainfall events and suspension flow was 10.36 minutes, and the suspension peak content varied by an average of 2.22 gl-1. The grain size was also dominated by the clay fraction, averaging 67.86% on the ascending branch and 67.82% on the descending branch. [ABSTRACT FROM AUTHOR]

Over the last few decades, numerous countries have invested vast sums of money and resources in addressing the effects of climate change through adaptation and mitigation measures. Part of these actions, however, resulted in maladaptation. This research investigates the adaptation response to climate change that (potentially) becomes maladaptation for both upstream and downstream watershed communities. This research uses a watershed approach located in the Saddang watershed, one of Indonesia's priority watersheds. The primary data were obtained from observation and in-depth interviews with villagers directly affected by extreme weather (droughts and floods) occurred between 2009 and 2020. The examination of satellite imagery yielded secondary data that revealed changes in land cover, sedimentation, and river flow. This study reveals that by applying a watershed approach, forms of maladaptation are found in the upstream area and have detrimental effects not only on the area itself, but also to the downstream. The upstream deforestation occurring in the period was closely related to the adaptation responses (maladaptation) to the effects of a long drought, which is likely to form a vicious circle between adaptation and exacerbating the impacts of climate change in the coming years. In addition, upstream maladaptations make downstream areas more vulnerable: they divert and create new hazards, and therefore vulnerability of other groups, although some positive examples of adaptation are also found downstream. Programs labeled "climate resilience" with increased food security are applied in both upstream and downstream regions, triggering maladaptation that has a wider impact and illustrating the non-consolidation of adaptation actions that take into account a watershed as a distinct landscape. [ABSTRACT FROM AUTHOR]

Payment for Environmental Services (PES) is an effort and commitment of the world community in tackling the symptoms of global warming and damage to the ozone layer that will affect global climate change. Using field research methods, research data is collected through in-depth interviews with stakeholders in environmental services return programs in this research area. Research data is analyzed and described qualitatively for further conclusions. The concept developed upstream and downstream watershed relationships through the PES mechanism is based on the principle of voluntary agreement and awareness of maintaining the watershed ecosystem. The experience of implementing the PES Program in the Cidanau Watershed of Banten Province of Indonesia, managed by an independent institution. The PES program, in addition to its role as an environmental conservation program in the Cidanau watershed, also has socio-economical benefits for the community, environmental service (ES) users, and providers. [ABSTRACT FROM AUTHOR]

Brantas Watershed covers almost all regions of the Greater Malang (the Batu City, Malang City, and Malang Regency) and Blitar Regency in the East Java Province. These four cities/regencies are in one landscape so that several strategic sectors are interrelated. Global climate change impacts the form of environmental disasters in this region, which is even more significant in the future. This phenomenon has changed the development paradigm in this region. The research conducted descriptive analysis and observation in these four administrative areas to reveal the impacts on particular sectors, evaluate the preparedness of the four local governments, and formulate the strategies to integrate the development agendas in the landscape of Upstream Brantas Watershed. The study found that vulnerability and risk studies need to be carried out in an integrated perspective, then the local governments need to strengthen their adaptive capacity and include this agenda in the development programs. Likewise, the resolution of the problem needs to be done together across administrative boundaries, which is often a different challenge in Indonesia's administrative form of decentralization. [ABSTRACT FROM AUTHOR]

The Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) model can be applied to simulate hydrological processes. This model has been widely used in recent days because it is openly accessible to the public. The search result from this study identifies 180 cases discussing the model applications in Indonesian watersheds in peer-reviewed journal articles and conference papers. The model has been used in Indonesia since 2005, but the highest application is in 2020 with 42 articles. In the context of application distribution, Java Island ranks first place with 123 scientific publications. However, the HEC-HMS model is predominantly used to simulate the "Small" and "Very Small" watershed size categories. The availability of insufficient field data is huge obstacle for hydrological modeling in Indonesia. Furthermore, the model may be extended to address the issues in Indonesia's eastern watersheds. Moreover, the model also can be used to assess the impact of climate change on streamflow. [ABSTRACT FROM AUTHOR]

The Dodokan watershed is one of the priority watersheds on Lombok Island, which is a mainstay for providing water for the community but has a high vulnerability to drought. This condition causes disruption to the fulfillment of water needs, so it needs to be anticipated early with mitigation actions. Understanding the trend of drought is needed as a basis for developing mitigation measures, especially related to land use in the watershed. This study aims to analyze the hydro-meteorological drought trend that occurred from 2009 to 2020 and to find out the role of land use improvement in mitigating drought, which is predicted in the next 10 years. The Thornthwaite–Mather method was used for drought analysis, and its predictions for the next 10 years were determined by using trend analysis. Land use simulation using a spatial analysis was carried out as an effort to prepare for drought mitigation actions. The results show that the drought in the Dodokan Watershed has increased in the period between 2009–2020 and is predicted to continue to increase. Land use improvement by restoring the forest is a more appropriate mitigation method to overcome the drought than rearranging the agricultural land on slopes above 25%. The simulation results have succeeded in increasing the water surplus and reducing the water deficit in 2030 so that it can be used for drought mitigation in the Dodokan watershed. [ABSTRACT FROM AUTHOR]

Natural disasters are common worldwide, especially in tropical countries. Floods are one such frequent disaster that occur in the tropical country of Indonesia. Floods cause disasters in many vulnerable societies living in the area. Therefore, it is necessary to conduct risk assessments for flood mitigation. The objective of this research is to support decision-making for flood risk assessment by selecting priority sub-systems. The research was conducted in Surabaya, East Java, and Indonesia. The Surabaya drainage system is divided into five districts consisting of several sub-systems facing inundation problems. This causes challenges for the government in selecting which sub-systems should be prioritized to overcome these problems. Consequently, a rank priority for sub-systems is required. This research validated whether the Analytics Hierarchy Process (AHP) method was applicable and appropriate to weight priority factors to select the priority drainage system. It weighs historical flood data by considering several criteria related to floods, consisting of flood hazards, social economics, and the environment. Flood hazard is defined as the severity level of flooding indicated by three indicators: inundation area, inundation depth, and inundation duration. Social-economics is a criterion covering population density and land use types consisting of residential areas, commercial and services areas, public facilities, industrial areas, port areas, and mix used development support areas. Environment is a criteria indicated by green open space, flood-prone areas, watershed catchment areas, and storage areas. The weighting result convinced the decision makers as to the related parameters which should be considered in order to support appropriate and effective flood mitigation. Further, due to budget constraints, the results of the research can be used to assist the municipal government in selecting which drainage system should be prioritized for management. The AHP result reveals that the priority drainage systems are Wonorejo sub system (Jambangan district), Greges sub system (Genteng district), Kedurus sub system (Wiyung district), Kalibokor sub system (Gubeng district), and Tambak Dono sub system (Tandes district). The result was confirmed to several respondents from Department of Public Works, Highways, and Drainage Management involved with the drainage system in Surabaya. It is indicates that the AHP results mostly are applicable to the existing condition. [ABSTRACT FROM AUTHOR]

Currently, the quantity, quality, and quantity of springs in various regions of Indonesia have changed or decreased. This is due to various factors, including deforestation and changes in how water catchment areas function. Limited data and information has been identified as a weakness in spring protection efforts. In this regard, an integrated, spatiallybased database that is easily understood and accessible to all parties is required for reference in planning activities. This research aims to provide the public with a complete picture of data and information on priority springs. Data was collected using the desk study method and interviews with relevant agencies, communities, and other stakeholders. The spring data collected included general, biophysical, socioeconomic and spring management information. Way Karang Spring was selected to be the subject of this research after several assessments. Based on the result, Way Karang Spring is classified as having interrupted status damage, and spring protection efforts are being made to restore the spring's quality. This spring is extremely important to the community. Way Karang Spring must be preserved to meet the water needs of the local community. [ABSTRACT FROM AUTHOR]

Land use with increasingly high intensity and not well planned, such as land conversion from agricultural land to residential and industrial areas has the potential to cause damage to watersheds indicated by a decrease in hydrological conditions. This land use change is an important phenomenon for every planner and regional policy maker. This research was conducted for seven months at the Cimanuk River Basin. This study aims to determine the pattern of land use in the Upper Cimanuk Watershed and the impact of land use in the Upper Cimanuk Watershed on irrigation water discharge in Majalengka Regency. The research method in this study used the image classification method, namely the process of dividing the coverage area based on image data with the use of certain symbols. In it there was an unsupervised classification and a guided classification. The results showed that Land use patterns in the Cimanuk River Basin are dry land agriculture by 30.02%, rice fields by 19.01%, production forest by 14.34%, and bush area by 0.32%. The average annual discharge in 2020 in the upstream of the Cimanuk River Basin that flows into the Rentang and Kamun dams were 125.32 m/s and 355 m/s. [ABSTRACT FROM AUTHOR]

There have been many studies on rainfall erosivity and erosivity density (ED). However, it was not widely developed in Indonesia as a tropical country and has unique precipitation patterns. They are indicators for assessing the potential risk of soil erosion. The Air Bengkulu Watershed is undergoing severe land degradation due to soil erosion. This study aimed to analyze spatial-temporal in rainfall erosivity and ED based on monthly rainfall data (mm). The data used consisted of 19 weather stations during the period 2006–2020 and which are sparsely distributed over the watershed. The analysis was done by using Arnold's equation. Then, the trend was tested using parametric and non-parametric statistics, and analysed with linear regression equation, and Spearman's Rho and Mann Kendall's tests. The spatial distribution of both algorithms was analysed using the inverse distance weighted (IDW) method based on the geographic information system (GIS). Unlike previous research findings, The long-term average monthly rainfall erosivity and ED revealed a general increase and decreasing trend, whereas it was found to be non-significant when both indices were observed. However, these results indicate a range from 840.94 MJ · mm−1 · ha−1 · h−1 · a−1, 552.42 MJ · mm−1 · ha−1 · h−1 · a−1 to 472.09 MJ · mm−1 · ha−1 · h−1 · a−1 in that November month followed by December and April are the most susceptible months for soil erosion. Therefore, The upstream area of the region shows that various anthropogenic activities must be managed properly by taking into account the rainfall erosivity on the environment and that more stringent measures should be followed in soil and water conservation activities. [ABSTRACT FROM AUTHOR]

The Cimanuk River with a total watershed area of 4010.8 km2 flowing from the Garut Regency to Indramayu Delta is the longest in West Java Province. However, the cumulative effects of climate change, increased population, and fish farming in the coastal area have continuously pressured the availability of water resources in its watershed. This study was, therefore, aimed to analyze the impact of land use and climate change on surface runoff and groundwater using a SWAT model. This is a physically based semi-distributed hydrological model with various applications, particularly to simulate water balance and watershed management. Daily discharge record for 2005–2008, land use data for 2002–2017, and the simulated climate (1979–2003) and projected climate data (2075–2099) retrieved from MRI-AGCM3.2 20-km by the Meteorological Research Institute of Japan Meteorological Agency were used in this research. The result showed that the calibration and validation of SWAT model have exhibited satisfactory criteria for hydrological simulations. The modeled period showed land use changes caused a general increase in runoff and decline in base flow contribution to annual streamflow. The changes between the current and projected climate exhibited increase in Qmax/Qmin ratio in certain years. [ABSTRACT FROM AUTHOR]

The identification and quantification of natural carbon (C) sinks is critical to global climate change mitigation efforts. Tropical coastal wetlands are considered important in this context, yet knowledge of their dynamics and quantitative data are still scarce. In order to quantify the C accumulation rate and understand how it is influenced by land use and climate change, a palaeoecological study was conducted in the mangrove‐fringed Segara Anakan Lagoon (SAL) in Java, Indonesia. A sediment core was age‐dated and analyzed for its pollen and spore, elemental and biogeochemical compositions. The results indicate that environmental dynamics in the SAL and its C accumulation over the past 400 years were controlled mainly by climate oscillations and anthropogenic activities. The interaction of these two factors changed the lagoon's sediment supply and salinity, which consequently altered the organic matter composition and deposition in the lagoon. Four phases with varying climates were identified. While autochthonous mangrove C was a significant contributor to carbon accumulation in SAL sediments throughout all four phases, varying admixtures of terrestrial C from the hinterland also contributed, with natural mixed forest C predominating in the early phases and agriculture soil C predominating in the later phases. In this context, climate‐related precipitation changes are an overarching control, as surface water transport through rivers serves as the "delivery agent" for the outcomes of the anthropogenic impact in the catchment area into the lagoon. Amongst mangrove‐dominated ecosystems globally, the SAL is one of the most effective C sinks due to high mangrove carbon input in combination with a high allochthonous carbon input from anthropogenically enhanced sediment from the hinterland and increased preservation. Given the substantial C sequestration capacity of the SAL and other mangrove‐fringed coastal lagoons, conservation and restoration of these ecosystems is vitally important for climate change mitigation. [ABSTRACT FROM AUTHOR]

High magnitude flash flood has occurred several times in some areas in Central Sulawesi Province after the 2018 Palu Earthquake, one of them is in the Bangga River, Sigi Regency, Indonesia. It has caused massive impacts such as damaging agricultural and plantation areas and submerging public facilities and infrastructure and even causing fatalities. The flood carries a variety of materials, especially high concentration sediments which are thought to originate from eroded soils due to landslides induced by a 7.5 magnitude earthquake. These materials are eroded and transported by the flow at the upstream watershed due to heavy rainfall. This study intends to investigate the potential of landslides, factors that trigger floods and increased flooding after the earthquake. This research was conducted by investigating the landslides potency based on field surveys and interpretation of the latest satellite imagery, analyzing the characteristics of rainfall as a trigger for flooding, and predicting the flood potency as the primary impact of these two factors. Rainfall-flood transformation was simulated with the HEC-HMS Model, one of the freeware semi-distributed models commonly used in hydrological analysis. The model input is the configuration of river networks generated from the National DEM (DEMNAS), hourly rainfall during floods and other watershed parameters such as land cover, soil types and river slope. The similar simulation was also carried out on the condition of the watershed before the earthquake. Based on the results of the analysis, It can be inferred that flash floods in the Bangga River are mainly caused by heavy rainfall with long duration and landslide areas in the upper watershed triggered by the 2018 Palu Earthquake with an area of approximately 10.8 km2. The greatest depth of rainfall as a trigger for flooding is 30.4 mm with a duration of 8 hours. The results of the study also showed that landslides in the upper watershed could increase the peak flood by 33.33% from 118.56 m3/s to 158.08 m3/s for conditions before and after the earthquake. [ABSTRACT FROM AUTHOR]

Indonesia and Philippines are homes of biodiversity in Southeast Asia. In recent years, however, there has been a decline in biodiversity brought about by land use change. This condition poses threat on the food security of communities around the watersheds. The type and volume of main food items depend on the ecological and physiological conditions of the watersheds, in this case, Way Betung and Molawin Dampalit. When edible food is sufficient and available in an area, there is higher livelihood that the communities are food secured. This paper argues based on research which has been conducted in May to November 2015 that the food security of communities in the selected agroforestry landscapes in Way Betung and Molawin Dampalit have moderate. Levels of its food security based on four dimensions, namely: food availability, food accessibility, food stability and food utilization. Amounted 261 Indonesia farmer's respondents and 106 Philippine's respondents mentioned that the farm households generally practice agroforestry where the production of short-term and medium-term agricultural crops, woody perennials and livestock are deliberately combined. The type of crops grown by farm households contribute to the level of food security. [ABSTRACT FROM AUTHOR]

Design flood is one of the important factors for flood risk assessment and water infrastructures planning and development in a certain location. There are several methods to estimate it, one method which has been commonly and widely use is using flood frequency analysis. This research aims to develop Intensity-Duration-Frequency (IDF) curves in Upper Werba Sub-Watershed, West Papua Province, Indonesia, to estimate design rainfall intensity. The design rainfall intensity is used to estimate peak of flood discharge using Rational Formula in the sub-watershed. Other methods, i.e. Soil Conservation Service and Nakayasu Synthetic Unit Hydrograph are also presented in this paper to provide comparison of the estimated peak of flood discharge. The result shows that the Rational method provide the closest magnitude of estimated flood discharge in Upper Werba Sub-Watershed to the observed streamflow. Therefore, it is suggested that the Rational method can be used for water infrastructure planning and development in the sub-watershed. [ABSTRACT FROM AUTHOR]

The downstream of the Kuranji watershed of Padang City is vulnerable to flood due to the changes of land use into settlements area. Land use changes have changed the soil physical properties and its infiltration. The inundation has changed soil physical properties, such as layers, textures, volume weight, pores, permeability, and soil organic matters. The objective of this research is to analyze the quality index of soil physical properties due to flood at the watershed of the downstream area of Kuranji River of Padang City. Research methodology adopted is by conducting a field survey. Location of the soil sample is selected by purposive random sampling and was analyzed at the Department of Soil Science Andalas University. Soil physical properties data was arranged as minimum data sets (MDS) to be analyzed with principal component analysis to identify the main factors most affected by the flood. The results show that the main soil physical properties influenced by the flood are texture and soil organic matter. Based on the calculation of selected values from the MDS data, the quality of the downstream Kuranji watershed is moderate to good. [ABSTRACT FROM AUTHOR]

The conversion of forests into agricultural land and the application of agro-technology on land without considering the capability and suitability of land will result breakdowns on Krueng Seulimum Watershed. This will obviously lead to high attrition, low land productivity in the upstream, sedimentation, and high fluctuation in the downstream. This study is aimed to: 1) predict the amount of erosion on every watershed land unit in Krueng Seulimum Watershed and 2) determine the appropriate agro technology (soil and water conservation techniques) for cocoa farms to suppress erosion (erosion < ETol). The method used in this study is a survey method with the following steps: 1) the preparation phase, 2) a preliminary survey, 3) a primary survey and 4) data analyses and result presentation. The prediction of was performed on each land unit (LU) and the cocoa -based farming systems (Cocoa, Cocoa + Areca nut, and Cocoa + Banana) using USLE. The results show that the greatest erosion prediction occurred on the shrub and dry land farming use. The predictive erosion values of the land use for shrub, dry land agriculture, grazing and secondary forest ranged from 30.71 - 292.98 tons ha-1 year-1 (ETol 31.50 - 40.96 tons ha-1 year-1), 27.60 - 118.19 tons ha-1 year-1 (ETol 39.11-40.96 tons ha-1 year-1), 9.92 tons ha-1 year-1 - 62.98 tons ha-1 year-1 (ETol 22.16 - 24.20 tons ha-1 year-1), and 1.31 - 6.94 tons ha-1 year-1 (ETol 23.98 - 29.28 tons ha-1 year-1), respectively. The agro technologies for soil and water conservation that should be implemented on agricultural dry land (cocoa, cocoa + areca nut, and cocoa + banana) are the provision of a complete fertilizer (7% slope), bunds terracing + grass planting to amplify the terrace (14% slope) and bund terracing + grass planting to amplify the terrace + mulching 6 tons ha-1 (21% slope). The forest land use is recommended to remain as forest, while the shrub land use is recommended for cocoa farming. [ABSTRACT FROM AUTHOR]

Papua is the final fortress of forests in Indonesia. However, floods recently occurred in Jayapura, Paniai, and Manokwari. If causal factors are not identified and early anticipated, the flood will become an annual disaster with more severe impacts. This study aims to identify main factors causing floods using scoring analysis. Data collected include: rainfall, river gradient, water discharge, drainage density, watershed shape, slope and land use. The research results show that the main factor of floods are average daily rainfall in wet month by 86.53 mm day-1 (rather high) with a score of 28, land use dominated by forest and plantation (rather low and medium) with a score of 21, watershed slope dominated by 1<8% (high) with a score of 5, drainage density of 6.4 (medium) with a score of 3, watershed shape (Rc of 0.30 < Re 0.71) with somewhat/elongated shape with a score of 2, and river gradient of 0.0062 (low) with a score of 2 respectively. High rainfall causes greater flow of water and runoff. Land use dominated by plantations (21.46%) is thought to be one of the main causes of floods in Masni District. Flood mitigation does not mean that rain should be reduced, but regulates/manages such as stopping the conversion of forest into palm oil plantations, reducing surface runoff by applying soil conservation, making bypass from meandering, dredging sediments, and constructing retaining walls. [ABSTRACT FROM AUTHOR]

Data and land resource information complete, accurate, and current is an input in management planning, evaluation, and monitoring Watershed. Implementation of this research is conducted with optimum utilization of secondary data that is supported by direct field measurement data, digitalizing the maps associated, Geographic Information Systems modeling, and model calibration. This research has resulted in a Geographic Information System Management of potential Watershed GIS Web-based or abbreviated WEB GIS MPPDAS using Palopo watershed area, South Sulawesi as a case study sites for the development of a prototype that consists of three applications the main website ie Web Portal, Web GIS, and Web Tutorial. The system is built to show online (and offline) maps watershed in the administrative area of Palopo along with the location of its potential accumulated in the four (4) groups of layers, including groups of main layer (2 layer), a group of base layer (14 layers), groups of thematic layers (12 layers), a group of policy layer (8 layer). In addition to display a map, use the WEB application of GIS MPPDAS can also use tools or controls in the application to perform analyzes in its monitoring and evaluation, including: Geocoding, Add layer, Digitizing, Selection, Measurements, Graph, Filtering, Geolocation, Overlay cartographic, and etc. [ABSTRACT FROM AUTHOR]

Satellite imagery has been widely used in many fields, including watershed management, environmental management, and disaster mitigation. In watershed management field, this dataset provides the land use map that is an input for watershed management planning and prediction of hydrology characteristics of a watershed. It can be done using hydrology model that requires detailed parameters such as: land use type, soil characteristics, topography, and climatic data. This research was conducted in Dodokan Watershed at Nusa Tenggara Barat Province with area of 54,279.25 ha. The hydrology characteristics of Dodokan watershed was predicted using the Soil and Water Assessment Tool (SWAT) model. Based on the analysis of three years rainfall datasets (2010-2012), land use map (2012) and soil characteristics data (2014) as well as average of curve number of 75.03, the highest surface runoff volume was 35.18 mm with the highest rainfall of 52.39 mm and runoff coefficient is 0.33. [ABSTRACT FROM AUTHOR]

• The distribution of available Si in the Sumani watershed (SW) were investigated. • Available Si content in river sediments higher than other land-use types. • Available Si or soil rich in Si was redistributed through soil erosion. • 3D soil-erosion map in the SW and distribution Si in soil were presented. • Available SiO 2 and erosion-factor analyses in the SW were presented. Silicon (Si) is an important element for rice plant, and its availability in soil is an important factor affecting sustainable rice production. Herein, the distribution of available Si and its correlation with land-use type and soil-erosion status were investigated and discussed using the universal soil loss equation (USLE) in the Sumani watershed (SW). This watershed is the main rice-production area in Sumatra, Indonesia. Results showed that the available Si levels in sawah soil were less than 300 mg SiO 2 kg−1 on average. Sawah means a leveled and bounded rice field with an inlet and an outlet for irrigation and drainage, respectively. Available Si content in river sediments was also studied and determined to be higher than those in sawah or other land-use types. This finding may indicate that available Si or soil rich in Si was redistributed through soil erosion. Soil-erosion rate was negatively correlated with the concentration of available Si in soils. Land-use types with smaller values of crop factor in USLE calculation and soil with lower pH showed relatively lower available Si in the soils. Overall, our findings indicated that soil erosion and land-use types affected the distribution of available Si in the watershed. [ABSTRACT FROM AUTHOR]

Recently, resolving a problem based on multi-criteria decision-making systems has become an attractive method. One of recent techniques is trapezoidal fuzzy VIKOR method which was used for selecting the best option among criteria. This research is aimed to utilize the VIKOR method in prioritization of watershed reforestation in Semarang City, Indonesia. Several criteria have been set for the prioritization of reforestation areas to select watersheds as reforestation targets. In this case, the six criteria and six alternatives were used in order to determine the best priority of reforestation. The result showed that VIKOR method was successfully applied to determine the best option and Kali Garang watershed was the top priority as it has the highest rank and it meets reforestation criteria compared with other watersheds criteria. [ABSTRACT FROM AUTHOR]