A Geomorphometric Approach to Estimate the Deterioration of Earthen Archaeological Sites by Rainfall and Diffusion Processes: The Huaca Chornancap (Eighth–14th Century ad ), Lambayeque, Peru

La región Lambayeque posee un rico legado cultural, cuyas evidencias, accesibles mediante investigaciones arqueológicas, colaboran con la construcción de nuestra identidad y a la generación de conocimiento. Por lo tanto, es importante proteger esta evidencia arqueológica y asegurar su perdurabilidad para el disfrute de futuras generaciones. El Gobierno central, a través del Ministerio de Cultura, emprendió un programa de protección del patrimonio arqueológico en la costa norte del país con la finalidad de mitigar el impacto de las lluvias del fenómeno de El Niño (ENSO – El Niño Southern Oscillation). Estas actividades en la región Lambayeque fueron canalizadas a través de la Unidad Ejecutora 005 Naylamp entre finales de 2014 e inicios de 2016, y abarcaron 28 de los sitios arqueológicos más vulnerables. Las acciones de conservación ejecutadas permitieron preparar a las áreas de intervención y dejarlas en las mejores condiciones posibles para poder enfrentar los embates de la naturaleza con mayor éxito. El siguiente artículo da a conocer sobre la territorialidad del patrimonio arqueológico en la región Lambayeque, según el diagnóstico físico espacial elaborado en el año 2015 como parte del Plan Maestro para el Mejor Manejo del Patrimonio Arqueológico de la Región Lambayeque.

Interactive effects of rainfall intensity, kinetic energy and antecedent soil moisture regime on splash erosion in the Ultisol region of South China

The interaction between rainfall erosivity parameters and splash erosion is crucial for describing the soil erosion process; however, it is rarely investigated under natural rainfall conditions. In this study, we conducted splash erosion experiments under natural rainfall on three sites in Central Europe. The main goal was to obtain the relationship between splash erosion of the bare soil in seedbed condition and commonly used rainfall erosivity parameters (kinetic energy, intensity, and rainfall erosivity (EI30)). All sites were equipped with a rain gauge and an optical laser disdrometer where the splash erosion was measured, with modified Morgan splash cups. In order to investigate which parameter best describes the splash erosion process for all sites, a regression analysis was performed. In total, 80 splash erosion events were evaluated. Splash erosion can be described as a linear function of total kinetic energy and a non-linear function of EI30. However, the use of the total kinetic energy led to underestimation of the splash erosion rates for highly intensive rainfalls. Therefore, better results were obtained when using average rainfall intensity as the splash erosion predictor or the kinetic energy divided by the rainfall duration. Minor differences between the replicates during splash erosion measurements indicate that the modified Morgan splash cup provides a good tool for soil erosion assessment.

Core Ideas Directional components of splash erosion and effects of raindrop kinetic energy were investigated. Lateral splash erosion played a significant role in supplying detached particles to adjacent areas. We fit equations for total and net splash erosion to rainfall physical parameters. We used cross‐validation to test the equations. Splash erosion is an important process of hillslope erosion. However, there is little information available in the literature to show how rainfall physical parameters affect the directional components of splash erosion. Therefore, the objectives of this study were to investigate the effects of rainfall physical parameters (rainfall intensity [RI], raindrop kinetic energy [KE], and raindrop diameter) on the directional components (upslope, lateral, downslope) of splash erosion characteristics in the Chinese Mollisol region. A specially designed soil pan, which can measure the directional components of splash erosion, was subjected to designed rainfall intensities of 50 and 100 mm h −1 and varying raindrop KE. The results showed that the total splash erosion (downslope plus upslope plus lateral splash erosion), directional components of splash erosion, and net splash erosion (downslope minus upslope erosion) on hillslopes significantly increased as RI and raindrop KE increased ( p < 0.05). Furthermore, splash erosion from downslope, lateral slope, and upslope contributed 32.2, 26.3, and 14.5%, respectively, of total splash erosion. Additionally, raindrop KE and raindrop median volume diameter ( D 50 ) were the key indicators affecting both total and net splash erosion. The equations between total and net splash erosion with both parameters of raindrop KE and raindrop D 50 were fitted. The cross validation results showed that the two equations had acceptable accuracy. Therefore, preventing raindrop impact by using conservation tillage methods, such as retaining crop residue or mulch cover, can effectively reduce splash erosion in the Mollisol region of Northeast China.

Abstract. Recent research explored an alternative energy-centred perspective on hydrological processes, extending beyond the classical analysis of the catchment's water balance. Particularly, streamflow and the structure of river networks have been analysed in an energy-centred framework, which allows for the incorporation of two additional physical laws: (1) energy is conserved and (2) entropy of an isolated system cannot decrease (first and second law of thermodynamics). This is helpful for understanding the self-organized geometry of river networks and open-catchment systems in general. Here we expand this perspective, by exploring how hillslope topography and the presence of rill networks control the free-energy balance of surface runoff at the hillslope scale. Special emphasis is on the transitions between laminar-, mixed- and turbulent-flow conditions of surface runoff, as they are associated with kinetic energy dissipation as well as with energy transfer to eroded sediments. Starting with a general thermodynamic framework, in a first step we analyse how typical topographic shapes of hillslopes, representing different morphological stages, control the spatial patterns of potential and kinetic energy of surface runoff and energy dissipation along the flow path during steady states. Interestingly, we find that a distinct maximum in potential energy of surface runoff emerges along the flow path, which separates upslope areas of downslope potential energy growth from downslope areas where potential energy declines. A comparison with associated erosion processes indicates that the location of this maximum depends on the relative influence of diffusive and advective flow and erosion processes. In a next step, we use this framework to analyse the energy balance of surface runoff observed during hillslope-scale rainfall simulation experiments, which provide separate measurements of flow velocities for rill and for sheet flow. To this end, we calibrate the physically based hydrological model Catflow, which distributes total surface runoff between a rill and a sheet flow domain, to these experiments and analyse the spatial patterns of potential energy, kinetic energy and dissipation. This reveals again the existence of a maximum of potential energy in surface runoff as well as a connection to the relative contribution of advective and diffusive processes. In the case of a strong rill flow component, the potential energy maximum is located close to the transition zone, where turbulence or at least mixed flow may emerge. Furthermore, the simulations indicate an almost equal partitioning of kinetic energy into the sheet and the rill flow component. When drawing the analogy to an electric circuit, this distribution of power and erosive forces to erode and transport sediment corresponds to a maximum power configuration.

Soil internal forces contribute more than raindrop impact force to rainfall splash erosion

PDF HTML阅读 XML下载 导出引用 引用提醒 降雨能量对东北典型黑土区土壤溅蚀的影响 DOI: 10.5846/stxb201412312613 作者: 作者单位: 中国科学院 水利部 水土保持研究所,中国科学院 水利部 水土保持研究所,西北农林科技大学 资源环境学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（41571263） Effects of raindrop kinetic energy on splash erosion in the typical black soil region of Northeast China Author: Affiliation: Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources,Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:溅蚀特征研究可揭示溅蚀发生机理，而现有研究大多用溅蚀量来表征溅蚀特征，不能全面准确地反应溅蚀作用过程。为此，基于改进的试验土槽进行室内模拟降雨试验，研究降雨能量对坡面不同方向溅蚀量及溅蚀过程的影响。试验设计包括2种降雨强度（50 mm/h和100 mm/h）和10个降雨能量，其中10个降雨能量是通过2种降雨强度（50 mm/h和100 mm/h）和5个雨滴降落高度（3.5，5.5，7.5，9.5、11.5 m）来实现的。结果表明：在相同降雨强度下，坡面总溅蚀分量均随降雨能量的增加而增大。次降雨坡面溅蚀量均为向下坡最大，其次为侧坡溅蚀量，而向上坡溅蚀量最小。当降雨强度由50mm/h增加至100mm/h时，坡面向上坡溅蚀量增加2.3-5.0倍，向下坡溅蚀量增加1.7-5.1倍，侧坡溅蚀量增加1.9-4.3倍，总溅蚀量增加1.9-4.5倍，净溅蚀量增加1.2-6.4倍。对于不同降雨能量处理，坡面溅蚀率均表现为坡面产流前随降雨历时的增加而递增，产流后迅速达到峰值，之后逐渐减小并趋于稳定。定量分析了各溅蚀分量、总溅蚀量、净溅蚀量与降雨能量的关系，提出了溅蚀发生的降雨能量阈值，发现雨滴溅蚀发生的临界能量为3-6 J m-2 mm-1，且向上坡溅蚀量，向下坡溅蚀量，净溅蚀量和总溅蚀量皆与降雨能量呈幂函数关系，而侧坡溅蚀量与降雨能量呈二次多项式关系。 Abstract:Splash erosion is an important form of soil erosion caused by the impact of raindrops. Raindrop kinetic energy is the principal factor that affects splash erosion, and studies on splash characteristics can reveal splash erosion mechanics. However, current studies only characterize the amount of splash erosion, which cannot accurately and comprehensively reflect the splash processes. Therefore, this study examines the effects of raindrop kinetic energy on splash erosion processes and on the amount of splash erosion from different directions on a hillslope. The experimental treatments included two rainfall intensities (50 and 100 mm/h) and 10 rainfall kinetic energies that were obtained with a combination of the two rainfall intensities and five raindrop falling heights (3.5 m, 5.5 m, 7.5 m, 9.5 m, 11.5 m); the slope gradient was set at 10°. In the experiment, all treatments were replicated twice. The soil used in this study was a Mollisol (USDA system of Soil Taxonomy), containing 3.3% sand, 76.4% silt, and 20.3% clay. The tested soil was collected from 0-20 cm depth in the Ap horizon of a maize field in Liujia Town (44°43'N, 126°11'E), Yushu City, Jilin Province, located in the center of the Mollisol region in Northeast China. This study was completed in the rainfall simulation laboratory of the State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Yangling City, China. A side-sprinkle rainfall simulator was used to apply rainfall and a soil pan was specially designed to measure both splash and sheet erosion. Results showed that directional splash erosion increased with the increase of raindrop kinetic energy for a given rainfall intensity. However, at each individual rainfall, the amount of splash erosion was in the order of downslope > lateral slope > upslope.When rainfall intensity increased from 50 to 100 mm/h, the total splash and net splash erosion increased 1.9-4.5 and 1.2-6.4 times, respectively; splash erosion on the upslope, downslope, and lateral slope were enhanced 2.3-5.0, 1.7-5.1, and 1.9-4.3 times, respectively. For all rainfall kinetic energies, splash erosion rate gradually increased with rainfall duration; when runoff occurred, splash erosion rate reached the maximum value, and then gradually decreased until reaching a steady state. According to the relationships between directional, total, and net splash erosion and rainfall kinetic energy, the critical energy for splash erosion initiation was 3-6 J m-2 mm-1. Splash erosion increased with an increase in raindrop kinetic energy above the critical value. Furthermore, the relationship between raindrop kinetic energy and upslope, downslope, total, and net splash erosion was expressed by power function, while raindrop kinetic energy had a quadratic polynomial relationship with lateral splash erosion. 参考文献 相似文献 引证文献

tRIBS-Erosion: A parsimonious physically-based model for studying catchment hydro-geomorphic response

Influence of freeze-only and freezing-thawing cycles on splash erosion

Forest fires can alter several soil properties influencing soil erosion and runoff processes in addition to removing all or part of the vegetative cover. These include organic matter content, aggregate stability and water repellency. Soil erodibility and saturated hydraulic conductivity depend on these properties and their response varies according to aggregate size. The objective of the study was to investigate how forest fires affect key soil properties and determine the potential impact of these on runoff and erosion processes. The A horizon of an acidic sandy loam was collected and subjected to a pine litter fire. The burned and control soil samples were separated into 4 size fractions: bulk (<5·0 mm), < 0·4, 0·4–2·0, and 2·0–5·0 mm. Organic matter (OM), aggregate stability mean weight diameter (MWD), and water drop penetration time (WDPT) were measured for each size class. Each size fraction sample was subjected to 0·5 h of simulated rainfall (55 mm h−1) for splash erosion measurements. Saturated hydraulic conductivity (K) measurements were performed on the same samples. Burning the litter decreased soil OM content but increased MWD and WDPT. Splash erosion increased greatly for the bulk and < 0·4 mm samples. MWD increased for the 0·4–2·0 and 2·0–5·0 mm size fractions despite a loss in OM and clay content in the burned soil. A surface crust never formed on the water repellent fine fraction leaving plenty of non‐cohesive material available for soil detachment. Increased water repellency reduced K for all size fractions. The data support the need for a specific soil erodibility index for post‐forest fire soils. Copyright © 2007 John Wiley & Sons, Ltd.

Terraces are a common Mediterranean feature influencing soils, slopes and subsurface hydrology; however, little is known about their impact on erosion processes, especially in humid regions. The purpose of this study was to assess how terracing after a fire affected erosion processes such as splash erosion. For 8 months, the study monitored splash erosion in three terraced plots, one plot under pre-fire conditions and the other two under post-fire conditions. Assessment of the impact of the terracing treatment in such plots was carried out by the installation of two different splash erosion quantitative systems: cups and funnels. An analysis of the splash data obtained in 17 rainfall events and meteorological data collected during each one of those periods was then performed. A significant positive correlation between the amount of rainfall and the splash erosion was observed. The two splash sampling systems show a high degree of concordance; however, the funnel-type model seems to be the most appropriate when it comes to preventing loss of splashed soil samples. The post-fire treatment with terracing leads to a smaller stability of surface soil aggregates, causing higher splash erosion rates. Sampling using the funnel system collects three times the amount of splashed soil than that collected by the cup system, although both systems correlate appropriately with the meteorological parameters.

Effects of land use change on soil splash erosion in the semi-arid region of Iran

Effects of rain characteristics and terracing on runoff and erosion under the Mediterranean

Splash erosion: A review with unanswered questions

The observed interannual Indian Ocean sea surface temperature (SST) variability from 1950 to 2008 is analyzed in respect to the spatial structure of the variability. The analysis is based on an objective comparison of the leading empirical orthogonal function modes against the stochastic null hypothesis of spatial red noise (isotropic diffusion). Starting from this red noise assumption, the analysis searches for those structures that are most distinct from the red noise hypothesis. This objective approach will put previously well and less known modes of variability into the context of the multivariate SST variability. The Indian Ocean SST variability is marked by relatively weak SST variability, which is strongly dominated by a basin wide monopole pattern that is caused by different processes. The leading modes of variability are the El Nino Southern Oscillation (ENSO) variability and the warming trend, which both project onto the basin wide monopole structure. Other more characteristic spatial patterns of internal variability are much less dominant in the tropical Indian Ocean, which is quite different from all other ocean basin, where characteristic teleconnection patterns exist. The remaining, ENSO independent, detrended variability is dominated by multi-pole patterns from the southern Indian Ocean reaching into the tropical Indian Ocean, which are probably primarily caused by extra-tropical atmospheric forcings. The large scale tropical Indian Ocean internal variability itself has no dominant structure. The currently often used dipole mode index (DMI) does not appear to present a dominant teleconnection pattern of the Indian Ocean internal SST variability. In the context of the objective analysis presented here, the DMI partly reflects the ENSO variability and is also a representation of the multi-dimensional, chaotic spatial red noise (isotropic diffusion) process. As such the DMI cannot be interpreted as a coherent teleconnection between the two poles.