Land-Use Changes in the Sele River Basin Landscape (Southern Italy) between 1960 and 2012: Comparisons and Implications for Soil Erosion Assessment

In river basins, the deep interrelationships between land-use changes, soil erosion and rivers and shoreline dynamics are clearer than at a national or regional scale. Southern Italy is an ecologically fragile, desertification-prone territory where land-use changes in the last decades were significant. Notwithstanding this, studies dealing with multidecadal land-use changes in large-sized river basins of Southern Italy and their implications on soil erosion are missing. In this study, we assessed the land-use changes that occurred between 1960 and 2012 in the 3245 km2-wide Sele River basin. We carried out GIS-aided comparisons and analysis of two land-use maps and interpreted the results in terms of soil erosion intensity based on a detailed review of the scientific literature. The results confirmed the trend of the inner areas of Italy and, in particular, of the Campania region moving towards more pristine conditions, with an increase in forest cover, mainly at the expense of grasslands. Agricultural areas remained substantially unchanged, while the area of urban settlements increased. The diffuse afforestation of slopes suggested an overall decrease in soil erosion intensity, which was fully coherent with the geomorphological evolution of both the Sele River and local shoreline reported in literature.

Contemporary Trends in River Flow, Suspended Sediment Load, and Soil/Gully Erosion in the South of the Boreal Forest Zone of European Russia: The Vyatka River Basin

Recent decades in the north of the East European Plain have been characterized by significant changes in climate and land use/cover, especially after the collapse of the USSR in 1991. At the same time, the hydrological consequences of these changes, especially changes in erosion processes and river sediment load, have been studied insufficiently. This paper partially covers this existing knowledge gap using the example of the Vyatka River basin. Draining an area of 129,000 km2, the Vyatka River is among the largest rivers in the boreal forest zone of European Russia. Cultivated land occupies about one-fifth of the river basin area; about three-fourths is covered by taiga forest vegetation. The results of state long-term hydrometeorological monitoring and information on land use/cover made it possible to reveal contemporary (since the 1960s) hydrological and erosion-intensity trends and their drivers within the greater (96%) part of the river basin. There has been a statistically insignificant increase in water discharge in the Vyatka River basin during recent decades. This is due to a statistically insignificant increase (for the entire basin studied) in the spring snowmelt-induced floodwater flow and a statistically significant rise in the discharge in the year’s warm and cold seasons. The main reason for the detected trends is increased precipitation, including heavy rainfall during the warm season. In contrast to this, the total annual suspended sediment load of the river (especially that which was snowmelt-induced) and, consequently, soil/gully erosion intensity have experienced a significant decrease in recent decades (up to 58% between 1960–1980 and 2010–2018). Land-use/-cover changes (a reduction of cultivated land area and agricultural machinery, a decline of livestock in pastures) following the collapse of the Soviet Union are considered the main reasons for this decrease. The most noticeable changes in water discharge, suspended sediment load, and erosion intensity were observed in the most agriculturally developed southwest and south parts of the Vyatka River basin. All the above trends may be considered with a high probability to be representative for the south sector of the taiga zone of the East European Plain.

Explicitly Analyze the Soil Erosion in the Karst and Non-Karst Area of Different Morphological Types in Guizhou of China

How to explicitly understanding the soil erosion intensity change in different geomorphological types is one of key issues in the field of soil and water conservation. According to classification criterion of soil erosion intensity of China, the spatial soil erosion data with the resolution of 10 m×10m in Guizhou Province were obtained by combing with the multi-resolution remote sensing data of ALOS, ZY-3, GF-1, Landsat and GDEMV2, and 2762 field sampling data in 2010 and 2015, respectively. a spatial analysis model of soil erosion was improved to analyze the spatiotemporal change of soil erosion intensity in karst and non karst area of Guizhou province, which involved the spatial soil erosion data and different geomorphological type data of Guizhou province. The results show that the soil erosion intensity decreased by 6468.13km 2 in Guizhou Province from 2010 to 2015. The dynamic change intensity in the high-altitude area is larger than in the low-altitude area. The soil change intensity in karst area is higher than in non karst area, especially in the high and middle elevation area in Guizhou province. Moreover, the decreasing ratio of soil erosion intensity in karst area is generally larger than in non karst area, which can be used to explain that the ecological restoration projects and water soil conservation polices carried out in karst area has a good effect, especially in western of Guizhou province from 2010 to 2015, one the other hand, the soil erosion in non karst area should also be focused by local government in the future.

Devastating hyper-concentrated flood on the Loess Plateau, China: simulations and implications

<p>Yellow River has long been suffered from floods and sedimentation in the history, and has brought great catastrophes to the Chinese nation. Therefore, the Yellow River is also called the “China’s sorrow”. From July 25 to 26 of 2017, most of the northern part of the Shanxi and Shannxi Province in the middle Yellow River basin encountered high intensity rainfall with the maximum rainfall of 223.6 mm. In the abstract below, we term this rainfall event as the “7.26 storm”. After the extreme rainfall, hyper-concentrated floods occurred in the Dali River and Wuding River, which are tributaries of the Yellow River. The objective of this research is to study the hyper-concentrated floods of the Wuding River (with a drainage area of 28460 km<sup>2</sup>) at hourly time-step with a numerical model. The model that we utilized is the Digital Yellow River Model (DYRIM), which a physically based spatially distributed model of watershed sediment dynamics. Due to lack of sub-daily observation data, we first calibrate and verify the model at daily time-step. Then we apply the model to simulate the 7.26 storm at hourly time-step. Results show the DYRIM could well reproduce the peak discharge, peak sediment concentration, flood timing and volume, when compared with the measured data. Furthermore, the DYRIM is able to (1) delineate spatial distribution of hillslope erosion intensity, maximum erosion intensity could reach 10000 t/km<sup>2</sup>; (2) provide information about proportion of different sources of sediment, channel erosion is the main source of the sediment to the outlet and (3) analysis the influence of check-dams on flow and sediment, the dam trapped about 40 millions tons sediment, their effect on water and sediment reduction under extreme rainfall events is limited though.</p>

Some Problems On Erozon Protection Of Soils in Azerbaijan

430 mkn.ha of land has been damaged by erosion processes in different countries around the world. Surface, cleavage and irrigation erosion is also widespread throughout the country. 43.29% of the total area is subjected to varying degrees of erosion. In some regions, especially the Nakhchivan AR, erosion processes cover 70% of the area. 66.6 of the total area of the southern slope of the Greater Caucasus has been eroded. In some areas of the country, the percentage of eroded farms is high. This figure is 51% in Lachin-Kalbajar zone, 57.9% in Guba-Khajmaz zone and 72.4% in Sheki-Zagatala. The newly formed splinters break down the farmland into small parts and make them useless. The following erosion intensity scale is presented. 1) net wash-up to 0.5 t / ha, 2) poor wash-up to 0.5 t / ha, 3) moderate washing 1-5 t / ha, 4) severe washing -5-10 t / ha, 5) very severe washing -10 t / ha. Different geographical areas of the country have also been identified the possible distances between stripes on different slopes. Soil preparation should be carried out with a strip of 1–2 m in every 3–5 m in areas of 10–200 incidence, moderate to severe, and 1.5–3 m wide in each of the 2–3 m in severely washed areas of 20–300 m. trench to be dug. In large areas with more than 15-200 thick, thick soils and where the tractor can operate, deforestation should be carried out on terraces. On the slopes where heavily washed and often rigid rocks are exposed, soil preparation can be used to make yards and ditches.

Spatiotemporal Characteristics of Freeze-Thawing Erosion in the Source Regions of the Chin-Sha, Ya-Lung and Lantsang Rivers on the Basis of GIS

Freeze-thawing erosion is mainly distributed in the tundra, which is one of the main factors affecting soil erosion and soil conservation and affects the economic development of relevant countries and regions. The study area was selected to the north of Tanggula Mountain and the south of Bayankera Mountain, to the east of The Qinghai-Tibet Plateau, as the headwaters of the Yangtze River and lancang River. The topography and climate were particularly prone to soil freeze-thawing erosion, and the ecological damage would seriously affect the production and life of people in the whole downstream area. Therefore, based on the analytic hierarchy process (AHP), this paper selects seven evaluation factors to analyze the temporal and spatial characteristics of freeze-thaw erosion in the study area and establishes a comprehensive weight evaluation model for freeze-thaw erosion. The results show that: (1) the evaluation model is effective, and the soil freeze-thawing erosion is strong in the whole research area; (2) the total area of the research area and the freeze-thawing erosion area are 418,843 km2 and 375,514 km2 respectively, the freeze-thawing erosion area accounting for 89.7% of the total research area, and the freeze-thawing erosion intensity ranged from 0.165 to 0.737; (3) the spatial distribution differs significantly, the freeze-thawing erosion intensity is mainly concentrated in high altitude areas, especially in the Tanggula Mountains; (4) slope, poor annual temperature, illumination, altitude and content of sand in soil accelerate soil freeze-thawing erosion, whereas vegetation index does not; wetness index enhanced the influence of vegetation coverage and sand content. (5) this research will provide scientific evidence for protection and restoration of ecological environment in the area.

Influence of the type of watershed on melt water runoff and soil losses on chernozem

Purpose: to establish the influence of the watershed form on the intensity of snowmelt water runoff and the bulk of eroded soil on the chernozems of Rostov region. Tasks: to analyze long-term (1970–2020) studies of surface runoff bulks, including various types (forms) of watersheds, from compacted and loose arable land; to establish patterns and to obtain the dependence of the bulk of washed soil on the runoff coefficient and the watershed form. Research methods are generally accepted; runoff sites were used on the slopes of Bolshoi Log in Aksai district Rostov region. The indicators of the erosion intensity which make it possible to judge the quantitative loss of soil volumes and bulk depending on the type of watershed, the volume of precipitation, the melt water runoff and other factors were studied. Results. It was found that the amount of soil washed off during melt water runoff varies within wide range, but in most cases does not exceed 3–10 t/ha. The erosion intensity most often coincides with the largest runoff layer, since in these cases it passes over the soil thawed from the surface. Soil washout is decreasing; in the period from 1970 to 1991, the average annual bulk of soil washed away from the fall plowed land was an average of 7.5 t/ha, and from winter wheat crops, 10.2 t/ha. In the next 20 years (1991–2009), soil losses from fall plows amounted to 4.6 t/ha, from winter crops – 6.8 t/ha, and in the last 10 years, respectively, 5.0 and 3.1 t/ha. Soil loss on the slope of the southern exposure was 0.65 from the northern one. In the rills of the northwestern exposure, the melt water runoff was 10–20 % higher than on the slopes between the rills; soil washout along the thalweg of rills reaches 40 % or more of the total bulk of washed out soil. Conclusions. These data, in combination with the conditions for the occurrence of the phenomena under consideration, are used for a scientifically grounded choice of a system of soil protection measures for an adaptive landscape farming system and their forecasting over time.

A Prediction Method of Wear for Volute Casing of a Centrifugal Slurry Pump

Volute wall wear situations directly affect a long time safe operation for the centrifugal slurry pump unit and the whole system. In the present study, internal flow field is numerically investigated in a solid-liquid centrifugal pump, and the volute wall wear caused by the solid-liquid two-phase flow is predicted with wear equation. A systematic analysis on the wear mechanism of the centrifugal pump volute wall is carried out deeply, including the volute wall wear region, wear rate, and the relationship among inlet flow rate, particle concentration, and particle size. The predicted high erosion intensity area shows good agreement with the experimental erosion area, and the predicted and experimental areas are both located at the volute angle of 180° and near tongue. Therefore, the wear equation put forward in the present study is effective for estimating the erosion intensity and predicting the erosion area around the volute casing of a centrifugal pump.