Estimation of Erosion Using the Universal Soil Loss Equation (USLE) Method in the Ranu Pani Watershed in the Taman Nasional Bromo Tengger Semeru

The land problem that commonly occurs in Ranu Pani Watershed is erosion. Ranu Pani Watershed is an area located in the mountains with very high soil erosion. Therefore, it is necessary to conduct good management in the upstream and downstream areas. The first step before carrying out the management is to analyze the occurrence of erosion in the Ranu Pani Watershed. The purpose of this research was to predict the potential erosion and the distribution of spatial data.. The results of the research showed that the erosivity value in the Ranu Pani Watershed was 961.44 and heavy to very heavy class (0.50-0.77) of erodibility, soil texture was dominated by silt, fine granular soil structure, and moderate dominant permeability. 56.80% of the area (158.27 ha) has a slop class III (15-30%) with the land cover are natural forest with lots of litter, grasslands, shrubs, and fields of onions and potatoes. Land management is managed cultivation follows the contour line but without conservation. The result of the calculation showed that almost all areas have potential erosion value exceed the permissible erosion determination, with the potential erosion value are 1.92-4246.28 tha-1 yr-1, the range of permissible erosion value are 0.029- 1.2 tha-1 yr-1, and the erosion hazard index value is 1.57-143442.49. The results of the spatial analysis showed that 64.39% of the area (179.41 ha) has a very heavy erosion hazard class and 69.50% of the area (193.66 ha) has a very high erosion hazard index.

Assessment of soil erosion hazard and its mapping using GIS technologies

The article presents a method for creating a territory erosion hazard integrated map using RUSLE integral model, Earth remote sensing data and GIS technologies. The studies carried out on this topic are presented, the analysis of which has shown a more active use of integral indicators of water-erosion processes in foreign scientific works. Urgency of updating methodology for studying erosion processes has been substantiated. Theoretical foundations of the application of integral models of soil erosion are given, the application of the RUSLE model is substantiated, and the optimal way of using this model is proposed. The research methodology has been developed, consisting of primary processing of remote sensing data, calculation of the factors of erosion development and creation of a territory erosion hazard integrated map. Based on the processing of aerial photography materials, a point cloud, a digital elevation model and an orthomosaic map of the study area were created. The results of the geoinformation analysis of the remote sensing data, which included calculation of the soil erodibility factor and the topographic factor, are presented. Based on the integral indicator of watererosion hazard, a complex map of the erosion hazard of the territory has been created. Main patterns of geographical distribution of the values of the integral indicator of the water-erosion hazard of the territory are revealed, devised methodology is assessed. It was found that the schematic map reflects the general pattern of water erosion processes: they are more active in places where more dissected relief is spread. Influence of the soil factor on the pattern of the schematic map is shown: the pattern in the territories occupied by sod-podzolic loamy soils qualitatively differs from the pattern on the lands where sod-podzolic sandy loam soils are widespread. Patterns on the schematic map of different parts of the developed linear forms of relief, formed by temporary streams, are described. It is shown that the proposed method can be used to assess the water-erosion hazard of the territory. The need to take into account a larger number of factors and to refine the assessment of existing ones is concluded.

Current condition of coastal protection structures of Meulaboh, Westcoast of Sumatra Island, Indonesia

Meulaboh is coastal city that has tourism potential. The city has been facing coastal erosion hazard since a long time from high energy wave activity coming from Indian Ocean. To protect the coast from the erosion hazard, a coastal defence structures were built along the city’s coast overlooking the Indian Ocean. Before the 2004 tsunami, hard structures built on the coast that open to waves from the Indian Ocean were damaged by daily wave activity. This study assess effectiveness of the current coastal protection structures protect coastline in the three coastal segments of the city, namely the Padang Seurahet, Ujung Karang and Kampung Pasir, in order to find out if the construction of the structures is the right choice. Related to the tourism potential of Meulaboh City also studied the possibility to expand the function of the structures. The coastal protection structures data for this study were mainly obtained from field observations in June 2021. Effectiveness of the structures protecting coastline were analysed based on technical criteria. Meanwhile, possibility to expand the function of the structures were analysed according to environmental condition of the coastal segments and types of tourism activity. The results of this study show that the hard structure that now exists on Meulaboh coast can protect the city’s coast from the hazard of erosion without negatively impacting the surrounding coastline. In addition, the structure is considered to be expandable to support the development of tourism potential of Meulaboh City. Thus it can be conclude that the choice of hard structure for coastal protection in most of Meulaboh coastline is appropriate.

Prediction of erosion using the USLE method in the Malino Sub Watershed

One of the problems that occur in the Sub DAS Malino is population growth. The increase in population in an area will increase demand to encourage the community to convert forest land into non-forest land, especially agricultural land. It has an impact on erosion and flooding during the rainy season. The amount of erosion that occurs can result in damage and a decrease in soil quality; therefore, it is necessary to predict erosion using the Universal Soil Loss Equation (USLE) method. This study aims to determine the level of erosion hazard in the Malino sub-watershed, Jeneberang watershed. The data used in this study include data on land cover, rainfall, soil, and slope. The results showed that Sub DAS Malino has high erosion on the open land cover with 800.02 ton/ha/year of 0.44% area of the Sub DAS Malino.

Assessment of Soil Erosion Hazard in Prambanan District Using RUSLE (Revised Universal Soil Loss Equation)

Prambanan District which located in Daerah Istimewa Yogyakarta Province has the potential for land degradation due to erosion processes. With the characteristics of annual rainfall more than 2000 mm / year, topography with a slope of more than 20% in upland areas, as well as the conversion of upland to dryland agriculture are factors that can trigger the erosion process more quickly. If the rate of erosion speed exceeds the ability of the soil to regenerate the soil body, its productivity will be disrupted and accelerate the formation of critical soil. Therefore, it is necessary to know the estimated rate of erosion, tolerable distribution of erosion, and the potential danger of erosion that occurs. The purpose of this study was to (1) predict the rate of erosion, (2) calculate the permissible erosion value, (3) identify the rate & index of erosion hazard. Data were collected using field surveys and soil sampling using stratified random sampling techniques with land units as the unit of analysis. The value of erosion was predicted using the Revised Universal Soil Loss Equation (RUSLE) method. The RUSLE method is described by the following equation, A=R*K*L*S*C*P, where; A as estimated averages annual loss of soil, R is the rainfall erosivity factor, K is the soil erodibility factor, LS is the slope length factor, C is the cover management factor, & P is the conservation practice factor. The results showed that the erosion value ranged from 0.39 - 268.55 tons/ha/year. Permissible erosion ranges from 8.4 – 15 tons/ha/year for Latosol and 27.4 ton/ha/year for Regosol. The Rate of Erosion Hazard is dominated by moderate erosion, covering an area of 1330.7 ha or 31.8% of the total area. The Erosion Hazard Index is dominated by the low class (<1.0) which is covered over 2703.1 ha or 64.61% of the total area.

Erosion and sedimentation analysis due to land use changes in the Krueng Pase watershed

Human interactions with watershed can have positive and negative impact. The positive impact can improve socio-economic conditions. However, the negative impact is the degradation of the watershed function. For example, it’s continued increase in erosion rate on the land. The purpose of this study is to analyze erosion and sedimentation due to land use changes using the Universal Soil Loss Equation (USLE) and Modified Universal Soil Loss Equation (MUSLE) methods. Data collecting to determine erosion and sedimentation values are rainfall, soil erodibility and soil moisture, land use, and river water samples. The biggest decreased land use changes occurred in forest by 5.87%, followed by agriculture which decreased by 0.65% and water body 0.047%. On the other hand, built-up area increased by 0.65% and land used for agriculture increased by 6.15%. Furthermore, the level of erosion hazard in the Krueng Pase watershed from 2009 to 2019 increased in area, the mild level of erosion hazard increased by 7.9% and the moderate level erosion hazard by 27.4%. The amount of sedimentation obtained using the MUSLE method in 2019 was 6,869,98 tons and in 2009 was 41,692,97 tons. Erosion valuein 2019 is relatively small compared to other years. It’s really depends on the rainfall and the discharge that occurs. Therefore, a good land management system, proper and appropriate technology used, eco-hydrology concept and the monitoring of land use change regularly are needed, so damage that impact the Krueng Pase watershed can be prevented and minimize.