MAPPING SOIL EROSION INTENSITY USING EROSION POTENTIAL METHOD (EPM): CASE STUDY – BOSNIA AND HERZEGOVINA

Soil erosion is one of the most significant forms of land degradation in the Bosnia and Herzegovina. The mapping of soil erosion in B&H, as in the study area, was realized 30 years ago (1979-1985). The past decades has been marked by the changes which retained visible tracks and caused numerous changes in the intensity of erosion processes. In this paper, the mapping of the recent state of erosion intensity was performed, and then an analysis of changes was made in relation to the state of 30 years ago. The erosion potential method (EPM) was used for mapping the soil erosion and calculation of gross annual erosion and sediment yield. Erosion Map of the Vrbas river basin was made in the scale of 1:25,000. This Erosion Map counts a total of 69 topographic sections and 4,524 erosion polygons (plots). According to the Erosion Map of the Vrbas river basin, 5,666.88 km2 of the study area is affected by erosion, while 621.71 km2 are accumulating sediments. Annual gross erosion in the Vrbas river basin is 1,223,989.60 m3/year, while sediment yield is 366,088.10 m3/year. These research results are important because this is the first soil erosion map for the Vrbas river basin with EPM methodology for the whole river basin on territory of Bosnia and Herzegovina. The results can be applied in the field of spatial and urban planning, water and soil management on the local and regional level.

Soil erosion is a product of natural and anthropogenic factors and, at the same time, an economic and environmental concern. One of the methods applied to calculate the intensity of erosion is the erosion potential method (EPM), with two possible procedures for determining the average erosion coefficient of an area: analytical and graphical. Using GIS and EPM methods, without field observations of erosion, based on cartographic materials and satellite images, erosion maps were created for 1970 and 2018, for part of the peri-urban area of Belgrade. Based on the created erosion maps, the values of the mean coefficients of erosion, as well as the arithmetic means for the study area, were determined for the settlements. The aim of the study is to assess the reliability of the mean coefficient of soil erosion, obtained from the erosion map created from the cartographic materials and satellite images, without field observations of erosion. Thus, the obtained values of the mean erosion coefficient were compared with the values obtained from the erosion map with field observation and the values obtained by the analytical procedure. Statistical analysis (F test) for 1970 and for 2018 determined a high degree of reliability (p < 0.05) of the mean erosion coefficients of the area obtained from erosion maps that were created from cartographic materials and satellite images without field observation. Regardless of the procedure for determining the mean erosion coefficient, a significant decrease in soil losses was observed, from 10.64 to 5.97 t ha−1year−1 (average annual specific production of sediments, year 1970 and 2018, respectively).

Erosion is a significant environmental challenge in Serbia, shaped by natural and human factors. Pronounced relief, fragile geological substrate, a developed hydrographic network, and a climate characterized by an uneven distribution of precipitation throughout the year make this area prone to activating erosion processes and flash floods whenever there is a significant disruption in ecological balance, whether due to the removal of vegetation cover or inadequate land use. Researchers have recorded approximately 11,500 torrents in Serbia, most of which were activated during the 19th century, a period of significant social and political change, as well as intensive deforestation and the irrational exploitation of natural resources. By the mid-19th century, the effects of land degradation were impossible to ignore. As the adequate assessment of soil erosion intensity is the initial step in developing a prevention and protection strategy and the type and scope of anti-erosion works and measures, this article presents the path that the anti-erosion field in Serbia has taken from the initial observations of erosion processes through the first attempts to create the Barren Land Cadastre and Torrent Cadastre to the creation of the Erosion Potential Method (EPM) and its modification by Dr. Lazarević that resulted in the creation of the first Erosion Map of SR Serbia in 1971 (published in 1983). In 2020, a new Erosion Map of Serbia was created with the application of Geographic Information System (GIS) technologies and based on the original method by Professor Slobodan Gavrilović—the EPM—without the modifications introduced by Lazarević. We compared the 1983 and 2020 erosion maps in a GIS environment, where the change in soil erosion categories was analyzed using a confusion matrix. The updated erosion maps mirror the shift in methodology from a traditional approach (Lazarević’s modification) to the modern GIS-based method (Gavrilović’s original EPM) and reflect technological improvements and changes in land use, conservation practices, and environmental awareness.

Soil erosion is expected to increase in the future due to climate change. Soil erosion models are useful tools that can be used by decision makers and other stakeholders to deal with soil erosion problems or the implementation of soil protection measures. Most of the modelling applications are using Universal Soil Loss Equation (USLE)-type models. In this study, we evaluate the applicability of the Erosion Potential Model (EPM) and its modified version (mEPM) for the estimation of the gross and net erosion rates at a global scale. The sensitivity analysis shows that the model results have the highest variability due to the soil protection (land cover) coefficient followed by the soil erodibility parameter. The models’ evaluations indicate that that the EPM cannot be applied to cold regions while the mEPM overcomes this issue. The erosion rates based on the EPM were 1.5–2.5 times larger than the ones obtained from the mEPM. Increasing the number of catchment properties as inputs to the model may help in improving the performance of the tested EPM and mEPM. Moreover, a comparison of net soil losses by mEPM with long-term suspended sediment yield data for 116 catchments located around the globe indicates a median bias of less than 10%, although the bias for around 1/3 of catchments was above 100%. Furthermore, a direct comparison with other soil erosion models such as USLE-type models is not possible since the EPM and mEPM do take into consideration other processes such as soil slumps and gully erosion and not just sheet and rill erosion. Therefore, as expected, the gross erosion rates by the EPM and mEPM are higher compared to the USLE-type models. Hence, the mEPM, despite its limitations, could be regarded as an interesting approach for the describing erosion processes around the globe and should be further tested using small- and medium-sized catchments from various climate zones.

Comparison of EPM and PSIAC models in GIS for erosion and sediment yield assessment in a semi-arid environment: Afzar Catchment, Fars Province, Iran

Yazd province is one of the arid provinces of Iran and such regions are expected to experience wind erosion. Unlike expectation, in the Zarak catchment area that is located at Yazd province, because of fixation of the soil surface, water erosion is more than wind erosion. On the other hand, due to daily temperature changes, geological formations split and then due to heavy showers, such split blocks provide ideal conditions for surface erosion. Of course, on slopes, rill erosion can be seen. Also in the waterways, when flow discharge increase, due to concentration of the kinetic energy of water in the bends of waterway, bank erosion is found. Given the importance of soil protection programs and determining the methods of management of erosion and sediment as well as the reduction of calculation and the detailed design of the dam size at the storage dams, it is necessary to estimate total size of annual erosion and sediment in a catchment area. The Zarak catchment area is no exception. On the other hand with respect to the existence of multiple methods to do this, using a method with more reasonable data and saving cost and time, in addition providing acceptable and realistic answer is needed. Of course many parameters are involved. According to these matters, in this study, to study erosion and sediment, quantitative methods of modified Pacific Southwest Inter-Agency Committee (P.S.I.A.C) and Erosion Potential Method (E.P.M), also qualitative Bureau of Land Management (B.L.M) method were used and in the end, the results were compared. With using topographic maps and aerial photos, the initial map of each type of erosion was prepared and then by combining them with data and maps of rocks sensitivity, erosion, geology, geomorphology, slopes, vegetation types and land capabilities, etc. a base map was prepared. After that, by conducting field inspection, base map’s information was controlled and status of various erosions, slope, vegetation, condition of the bed and banks of the waterways, width and depth and materials of the bed and waterways were determined. Also erosion forms classes and their ranges were identified and the most important factors involved in the intensification of erosion were identified with using modified P.S.I.A.C, E.P.M and B.L.M methods.In the end ,the results of the three methods were compared.

Soil is an important natural resource whose proper use requires a good knowledge of all endogenous and exogenous factors that cause different types of degradation. Erosion is one of the forms of soil degradation. Erosion processes are characterized by a distinctive complexity and the factors affecting them are dynamics and change in space and time. A complex system degradation requires a multidisciplinary approach to the use of modern methods and techniques. Today, a large number of models are available for the assessment of soil loss through erosion as well as the levels of risk from erosion, today. Most of these are based on the logics of GIS thanks to its ability to sublimate heterogeneous information. In this paper, the analysis of spatial and temporal degradation of natural resources is carried out in the Likodra River watershed. The Likodra River is located in the northwestern part of the Republic of Serbia, and is positioned in the municipality of Krupanj. The main stream in the immediate vicinity of the town of Krupanj formed from four small streams that have expressed torrential character (the Bogostica with the Krzava and the Cadjavica with the Brstica). In May 2014, the urban area and rural parts of the municipality Krupanj were affected by catastrophic flash floods that resulted in the loss of human lives and enormous material damage. Soil degradation in the study area was analyzed using the Erosion Potential Method (EPM). The method is characterized by a high degree of reliability for determining the intensity of erosion, calculation of sediment yield and transport. The advantage of this method compared to other methods its lower complexity in terms of quantity of input parameters, simplicity and the possibility of application in GIS. In addition, the method has the advantage of choice, because it was developed in this area. The method is based on the analytical processing of data on factors affecting erosion. As the erosion spatial phenomenon appears on the map according to the classification on the basis of the calculated analytical erosion coefficient (Z), which depends on the characteristics of the soil, vegetation cover, relief and visible degree of erosion. By applying the Erosion Potential Method (EPM) an erosion map has been developed, showing the spatial distribution of erosion processes in the catchment area of the Likodra River watershed. The erosion map provides an insight into the state of erosion processes of different intensity and character. For the study basin, all its visible manifestations are manifested in the medium coefficient of erosion Zsr = 0.204. The current state of erosion was analyzed in comparison with the situation in the original 1983 erosion map of FR Serbia.

典型草地的土壤保持价值流量过程比较

In 2008, a new principle of spatial planning was added to the German Federal Spatial Planning Act. It demands critical infrastructure protection (CIP) be taken into account in all spatial planning activities. Since the term 'critical infrastructure' is quite young, this problem has not yet been explicitly treated in spatial planning activities. This paper presents results from a qualitative analysis of available regional spatial structure plans and from a survey of all regional spatial planning authorities in Germany. It shows that regional spatial planning has marginally dealt with CIP related questions like infrastructure reliability and spatial exposure in the past. However, the CIP concept, in addition to regional spatial planning methods and procedures, needs comprehensive efforts to approach and synchronise both public functions.

To implement soil conservation approaches, it is necessary to estimate the amount of annual sediment production from a watershed. The purpose of this study was to determine the erosion intensity and sedimentation rate from a watershed by employing empirical models, including the modified Pacific Southwest Inter-Agency Committee (MPSIAC), the erosion potential method (EPM), and Fournier. Moreover, the accuracy of these empirical models was studied based on field measurements. Field measurements were conducted along two reaches of Babolroud River. Total sediment transport, including suspended load and bed load, was predicted. Bed load transport rate was measured using a Helly–Smith sampler, and suspended load discharge was calculated by a sediment rating curve. The results of this study indicate that the erosion intensity coefficient (Z) of the Babolroud watershed is 0.54, with a deposition rate of 166.469 m3/(km2.year). Due to the existence of unusable crops, the highest amount of erosion appeared in the northern region of the watershed. The results using the EPM and MPSIAC models were compared with field measurements and indicated that both models provided good accuracy, with differences of 22.42% and 20.5% from the field results, respectively. Additionally, it could be concluded that the Fournier method is not an efficient method since it is unable to consider the erosion potential.

Among land degradation processes, soil erosion is the most serious threat to soil and water conservation in semi-arid regions. At the present study, the sedimentation hazard and the erosion zonation were investigated at Kardeh watershed, north-east of Iran by Erosion Potential Method (EPM) and Pacific Sonth-west Inter Agency Committee (PSIAC) models, in combination with the geographical information system (GIS) data, satellite data and field observations. According to our investigation the study area can be categorized into heavy, moderate and slight erosion zones with the total sediment yield of 147859 and 148078m3/a estimated by EPM and PSIAC models, respectively. The sub-basins located at the middle and south parts of the watershed are highly eroded due to the geology formation and soil erodibility conditions, while the sub-basins at the north parts are moderately eroded because of the intensive land cover. The amounts of the sediment yield in most areas are found to be consistent between the EPM and PSIAC models (R 2 = 0.95). Our data suggest the applicability of both empirical models in evaluating the sediment yield in arid and semi-arid watersheds.

Unraveling the paradox of soil erosion and conservation: Insights from China

The aim of this research was to analyse the changes in the soil erosion intensity caused by erosion control works (ECW) in Grdelica Gorge (The South Morava River) in the period between 1953 and 2016. For the purpose of quantifying the erosion intensity changes, the erosion potential model (EPM) was used to calculate the annual gross erosion (W), sediment transport (G), and erosion coefficient (Z) in the study area. As a result of the performed technical and biotechnical erosion control works, there was a general decreasing trend in the intensity of soil erosion processes in the last 63 years. The specific annual gross erosion in Grdelica Gorge was 1920.34 m3/km−2/year−1 in 1953, while in 2016 it was 492.42 m3/km−2/year−1. The specific sediment transport was 1421.05 m3/km−2/year−1 in 1953 and 364.39 m3/km−2/year−1 in 2016. Due to the changes in the intensity of erosion processes, the specific annual gross erosion in the study area decreased by 1427.92 m3/km−2/year−1 and the specific sediment transport by 1056.66 m3/km−2/year−1. The value of the erosion coefficient was reduced from Z = 0.84 in 1953 to Z = 0.32 in 2016. The results show that there is a significant correlation between the soil erosion intensity (erosion coefficient) and ECW (biotechnical works) performed in Grdelica Gorge. The permanent control of erosion processes in Grdelica Gorge is very important for torrential flood prevention and protection of two very important traffic routes (Belgrade-Skopje-Athens railway and motorway—Corridor X), as well as settlements, local roads, and other facilities in this area. Furthermore, these results are the basis for future water mana­gement projects, soil and environmental protection, spatial planning, agriculture, and other human activities.

This paper is dealing with soil erosion assessment using two different approaches: nuclear model and erosion potential method, also known as Gavrilovic's method. Complex valley systems on Titel Loess Plateau were selected for investigation. Radiocaesium is favored in many studies as an optimal erosion tracer due to its relatively long half-life, negligible renewal in the environment and strongly binding ability onto soil particles. The use of gamma-spectrometry in environmental testing laboratories acts as a precise and fast measurement technique for determination of 137Cs activity concentrations, without the need for complicate preparation of samples. Annual erosion and deposition rates were estimated according to three conversion models for uncultivated land: the profile distribution model with two years of dominant fallout of 137Cs (1963 and 1986) and the diffusion and migration model using WALLING software. The applied nuclear models were validated by comparison with erosion potential model which is the most relevant empirical model for erosion processes in torrent valleys. The obtained results indicate a good agreement with overall low values of average annual soil erosion rates on all soil profiles in the investigated area. Correlation analysis has determined the different influence of slope, terrain curvature, and vegetation index on the erosion models.

Accelerated soil erosion and high sediment production are important issues in many parts of Iran. The identification of high erosion risk regions is necessary for the planning of soil and water conservation measures in oreder to reduce erosion damages. In the absence of gauged small watersheds, empirical models are requierd for estimating soil erosion and sediment yield. The Erosion Potential Method (EPM), originally developed in Croatia, is a common erosion estimating model in Iran. Therefore, a calibration study was carried out by comparison between model estimated and measured sediment yields through sediment survey in 63 resorvoirs at the outlet of small chatchments in nine provinces. All required maps and informations of the study basins for estimating the EPM sediment yield were produced via field survey as well as data analysis. Comparison of the results showed that in most cases, the model estimates are lower than the measured sediment yields at the reservoirs. In this step, we calibrated the EPM by modifying its original tables and evaluated the results using Nash‐Sutcliffe efficiency coefficient in two scenarios, a) all basins and b) after dividing into three geographical zones, which significantly improved the estimates. The Nash ‐Sutcliffe efficiency coefficient for the scenario (a) was 0.66, and for the (b) scenario it was obtained 0.68, 0.5 and 0.89 for the Central, Zagros and Northeast zones, respectively. Based on the results, it is strongly recommended to use the modified EPM instead of the original model