Terrace Area Research Articles

Geotechnical Evaluation of Landslide in Nanggerang Village

Landslides are significant geological events that can cause extensive damage to infrastructure, disrupt communities, and pose serious safety hazards. Understanding the mechanisms behind slope failures is crucial for effective risk mitigation and the development of engineering solutions to improve slope stability. According to data from the National Disaster Management Agency (BNPB), Indonesia experienced 83 landslide events from January to February 2024. A notable landslide occurred in Nanggerang Village, Sukasari Sub-district, Sumedang Regency, West Java Province, on February 3, 2024. This landslide happened in a terraced rice field area following heavy rainfall earlier in the day. This study focuses on evaluating the failed slope to understand its condition just before failure and the material properties that influence the landslide event. The research methodology includes field data collection, soil testing, and slope stability analysis using the Limit Equilibrium Method (LEM) with a probabilistic approach via Slide 2 software. The analysis revealed that the failed slope had an average safety factor (FS) of 0.968 and a landslide probability of 58.897%. Sensitivity analysis showed that the cohesion parameter in the soil layer (CWZ) significantly impacts the safety factor of the slope. The study concludes that the reduction in soil cohesion and internal friction angle due to excessive moisture was the primary cause of the landslide, and the cohesion parameter of the soil layer is the most sensitive factor affecting slope stability.

Driving factors and trend prediction for annual runoff in the upper and middle reaches of the yellow river from 1990 to 2020

The Yellow River Basin (YRB) plays a pivotal role in the water resources management of its region, significantly influenced by the interplay between climate change and human activities, particularly in its upper and middle reaches (UMRYR). This study aims to elucidate the evolving patterns and determinants of runoff within the UMRYR, a matter of considerable importance for the basin’s water resource management, strategy, and distribution. Utilizing the Google Earth Engine (GEE) platform, this research accessed comprehensive datasets including precipitation, drought index, and terrace area, among others, to examine their effects on runoff variations at five gauge stations across the YRB. Terrace data was extracted from Landsat imagery via the Random Forest Model, while annual runoff figures from 1990 to 2020 were sourced from the Sediment Bulletin of China River. Employing the Mann-Kendall test, we assessed the temporal changes in runoff over three decades. In addition, runoff drivers were analyzed by stepwise regression and redundancy analysis, leading to the construction of a multiple linear regression model. The accuracy of predicting annual runoff using the multiple linear model was verified through cross-validation and comparison with the ARIMA time series model. Our findings reveal the efficacy of the random forest algorithm in classifying terraces, achieving an accuracy rate exceeding 0.8. The period from 1990 to 2020 saw a general increase in annual runoff across the five gauging stations in the UMRYR, albeit with variations in the pattern, particularly at the Tangnaihai gauge station which presented the most complex changes. Crucially, three main drivers—summer precipitation (SP), terrace area (TR), and drought index (DI)—were identified as significant predictors in the regression models. The multiple linear regression model outperformed the ARIMA model in forecasting accuracy, underlining the significance of integrating these drivers into runoff prediction models for the UMRYR.

Spatial patterns, determinants, future trends, and implications for the sustainable use of terraces abandonment in China

Terrace abandonment in hilly and mountainous regions, particularly in China, has become a significant concern. However, comprehensive assessments of abandonment patterns and underlying causes are still lacking. This paper elucidates the patterns, determinants, and impacts of terraces abandonment in China by using data from a survey of 580 villages across 346 counties and employing spatial analysis and the Heckman two-stage model. Terrace abandonment, which began in the 1990s, has progressively intensified, peaking in 2015. Currently, 51.55% of surveyed villages experience terrace abandonment, affecting 21.17% of households and 8.37% of the total terrace area, with a distinct prevalence in the South and scarcity in the North. Key factors contributing to terrace abandonment include low returns compared to other options, wildlife damage, high engagement in non-farm labor, and substantial non-farm income. In 2021, terrace abandonment led to the loss of 9.36 million tons of grain production capacity, enough to fulfill the yearly consumption requirements of 23.4 million people. Moreover, terrace abandonment undermines the cultural importance of terraced agriculture, reduces tourism potential, and hinders rural rejuvenation. The challenge of terrace abandonment is anticipated to worsen with the increase in non-farm economic activities and ecological restoration projects in hilly and mountainous regions. It is crucial for the government to implement measures to enhance terrace management. These measures include reducing operational costs for large contiguous plots, promoting the cultivation of cash crops to increase revenues from extensive scattered plots, and advocating for the reforestation of agricultural land to enhance the ecological value of remote terraces at higher altitudes. Addressing these issues can achieve sustainable terrace use and management, contributing to broader rural development and ecological goals.

Penerapan Metode Quality of Service (QoS) dalam Analisis Kualitas Jaringan Internet Burjo Pantry Semarang

The rapid progression of technology enables humans to exchange data and communicate remotely, eliminating the need for face-to-face interactions. The internet network, a product of this technological advancement, undergoes evaluation through the Quality of Service (QoS) method, which measures network service quality. This research focuses on assessing the internet network quality at Burjo Pantry in Semarang, utilizing a quantitative approach with a Quality of Service analysis. The throughput results reveal 1682Kbps in the terrace area and 7266Kbps indoors at Burjo, both categorized as 'very good.' Likewise, the delay, with 128,75ms in the terrace and 145ms indoors, falls into the 'very good' category. Both areas exhibit excellent jitter: 1,77ms for the terrace and 26,46ms indoors. Packet loss is minimal, with 1,73% in the terrace area and 0,68% indoors, both considered 'very good.' Overall, the study indicates the commendable quality of the internet network at Burjo Pantry in Semarang.

Hazard Analysis and Vulnerability Assessment of Cultural Landscapes Exposed to Climate Change-Related Extreme Events: A Case Study of Wachau (Austria)

The present paper aims to study the Wachau Valley in Austria as a representative Cultural Landscape under threat from extreme hydrometeorological hazards linked to climate change. The primary objective is to investigate the impacts and assess the vulnerability associated with the events of heavy rain and flooding. The methodology employed consists of an investigation of recorded past events impacting the Wachau; a vulnerability ranking system; a climate time series analysis based on earth observation products; and future hazard maps at territorial level, developed with outputs from regional and global climate models. The investigation we carried out provides a vulnerability assessment of two terraced areas with a surface of about 10,000 m2 in total, characterized by the presence of dry stone walls, with different state of conservation in the Municipality of Krems (Wachau). In addition, climate projections at territorial level for the extreme climate indices R20mm, R95pTOT, and R×5day—selected for investigating the likelihood of increases/decreases in events of heavy rain and large basin flooding—are provided, with a spatial resolution of ~12 km for the near and far future (2021–2050; 2071–2100) under stabilizing (RCP 4.5) and pessimistic (RCP 8.5) scenarios. The results indicate a general increase for the three indices in the studied areas during the far future under the pessimistic scenario, suggesting a heightened risk of heavy rain and flooding. These findings aim to inform policymakers and decision-makers in their development of strategies for safeguarding cultural heritage. Furthermore, they serve to assist local stakeholders in enhancing their understanding of prioritizing interventions related to preparedness, emergency response, and recovery.

Outdoor trends and indoor investigations of volatile organic compounds in two high schools of southern Italy

Volatile organic compounds (VOCs) are a class of ubiquitous substances that are present in outdoor and indoor air. They are emitted by a wide range of sources and can penetrate and accumulate specifically in indoor environments. Concern is growing among the scientific community regarding the potential health impacts of exposure to a high concentration of VOCs in indoor spaces. Due to their still-developing respiratory and immune systems, children may be the most fragile subjects in this regard, and therefore, the study of indoor air quality in schools is of the utmost importance. In this work, the concentrations of total volatile organic compounds (TVOCs) and of 20 specific compounds belonging to this class were determined in a school in Squinzano, a town in the province of Lecce (Apulia region, southern Italy). Sampling was carried out in indoor (classrooms and bathrooms) and outdoor (terrace) areas using passive diffusive samplers for VOCs and photoionization detectors for TVOCs. Average concentrations of both TVOC (303 ± 47 µg m−3) and individual VOCs (< 0.5 µg m−3) were below levels of concern; however, specific indoor sources such as cleaning activities and student occupancy were responsible for peaks in TVOC concentrations above harmless levels for children and school staff. The data were then compared to the ones obtained in a similar study conducted in a school in Galatina, another town of the Apulia region, highlighting the impact of the surrounding outdoor environment on the indoor profile of VOCs.

Mapping long‐term terrace change in the Chinese Loess Plateau: A new approach by decision tree model with digital elevation model (DEM) and land use

AbstractHuman‐created terraces are distributed extensively in the Chinese Loess Plateau, which play key roles in soil conservation, agricultural production and sustainable development. However, large‐scale and long‐term terrace mapping remains a big challenge due to the complexity of topography, land cover and the deficiency of high‐quality historical spatial data. Facing this task, our study aims to develop a new approach for capturing 30 years (from 1990 to 2020) of terrace patterns at macroscales (the whole Loess Plateau, with an area of 6.4 × 105 km2). The decision tree model (DTM) was integrated with digital elevation model (DEM) and land use data to detect terrace change, and terraced samples were extracted from existing findings for spatial validation. Our study confirmed that this new approach can work successfully on identifying cultivated and grassy terraces, as evidenced by receiver operating characteristic (ROC) curves and area under curve (AUC) values. More notably, a decreasing trend was detected in cultivated terraces with continued uneven distribution from 1990 to 2020, while the areas of grassy terraces increased markedly with more‐concentrated larger patches. This finding indicated that huge areas of terrace abandonment may have already occurred in this region. More attention thus should be paid to the rising risks of cropland utilization and food security. Since it is the first time to get long‐term reliable terrace maps on the Loess Plateau, our efforts can help to better take stock of terrace resources for wiser land use managements and agricultural policy adjustments, finally benefiting socio‐ecological sustainability.

Planning for Cikapundung Terrace Development in the Cikapundung River Watershed, Bandung City

Bandung, as one of the centers of development in Indonesia, continues to transform to meet the increasingly complex needs of the community. One development project that has attracted attention is the "Cikapundung Terrace Development Planning in Coblong District." The Cikapundung Terrace symbolizes the harmonious interaction between nature and urbanization, creating a comfortable and sustainable space for the citizens of Bandung. This research adopts a literature study approach, especially in the form of a literature review, with the selection of a narrative review model. The study procedure in this narrative review model involves comparing data from a number of international journals that have been analyzed and then compiled in a summary based on the author''s experience, theories, and relevant models. The research method implemented is qualitative, using data sources in the form of secondary data obtained from a number of international journals, articles, and previous studies that have been analyzed by the author related to the issues that are the focus of this research. This research adopts an analytical descriptive method by collecting, identifying, compiling, and analyzing various data found. From the above explanation, it can be understood that the development of the Cikapundung Terrace provides an opportunity to improve the economy of the community while adding a tourist destination and a place for social activities in the community. At the local level, the presence of Teras Cikapundung creates economic potential in various ways. First of all, the presence of this tourist spot can create direct employment opportunities, such as janitors, recreational facility operators, and administrative personnel. In addition, the emergence of small businesses such as food and souvenir vendors around the Cikapundung Terrace area can have a positive economic impact on local businesses. The Cikapundung basin is a mirror of how urban development can be integrated with sustainability and community well-being. As a successful model, the project can serve as an inspiration for the development of other green open spaces in different regions. Through a joint effort between the government, academic institutions and the community. It can be concluded that the Cikapundung Terrace Development Planning in the Cikapundung River Watershed of Bandung City has achieved its objectives.

Long-term terrace change and ecosystem service response in an inland mountain province of China

The exploration of terrace change and its associated ecosystem services (ESs) provides invaluable insights into the intricate interplay between engineering initiatives and environmental conditions. This understanding is crucial in designing strategic plans for environmental management. However, how terraced fields area change and influence ESs over an extended period at a regional scale remain relatively unknown. To bridge this knowledge gap, this study focused on terraces in Gansu Province (a typical inland mountain province), Northwestern China, by dividing the study area into seven regions, the quality and value benefits of unit area, the overall and cumulative of terraces were calculated for each region in Gansu province based on remote-sensing data, meteorological data, terraced area and benefits data. In this regard, the distribution, spatiotemporal changes and ESs associated with terraced fields in Gansu were examined from 1990 to 2020. The results show that: (i) terraces with the area of 2.20 × 104 km2 accounts for 81.34 % of counties(districts) of Gansu province in 2020, mainly located in the loess hilly and gully region (82.72 %). (ii) From 1990 to 2020, the terrace area in Gansu expanded from 8.13 × 103 to 2.20 × 104 km2, peaking at 636.73 km2/yr during 1990–2000, with notable spatial heterogeneity. (iii) In terms of ESs’ quality benefits, soil conservation benefits of terraces were the most significant, reaching 91.30–98.32 % per unit area, the cumulative benefits (1990–2020) were 1.82 × 109 t, followed by water conservation benefits (42.12–89.20 % and 2.36 × 1010 m3). (iv) Terraces expansion have increased the ecosystem service value by 815.10 million Dollar ($), with regulating services and habitat services accounting for 34.92 % and 31.92 %, respectively. These results indicate that the enormous potential value of terraces in ecological environment governance and ecological economic benefits, and provide a scientific support for understanding terraces and leveraging their ecosystem functions, while also offering valuable insights for the conservation of global mountain ecosystems and the improvement of human well-being.

Evaluating the effect of natural-artificial linear landscape elements on flow and sediment connectivity in a typical agricultural terraced catchment, China

Linear landscape elements, such as man-made ditches and road networks, play a pivotal role in the transport of water and eroded sediments. Yet very few studies have focused on the variations in drainage flow paths disturbed by artificial linear landscapes and their contribution to flow and sediment connectivity (FSC). This study utilized the index of connectivity (IC) to examine and distinguish the impact of natural and artificial linear landscape elements (i.e., natural streams, man-made ditches, and road networks) on the spatial distribution of FSC. The method was employed in a typical agricultural terraced catchment of the Honghe Hani Rice Terraces World Heritage Site of China, based on two weight factors - roughness index (RI) and Rndvic factor. The results indicate that the incorporation of the linear landscape elements for the IC calculation remarkably affected the spatial distribution of FSC. Specifically, FSC values notably increased by closing the distance to linear landscape elements within a specific threshold. Moreover, in the confluence between natural and artificial linear landscape elements, the mean value of FSC was higher compared to scenarios without any or only one linear landscape element. In comparison, the presence of road networks only improved lateral connectivity by modifying the surface flow along east-west directions, while man-made ditches significantly influenced both longitudinal and lateral connectivity to a larger degree, especially in the terraced area. This finding underscores the effectiveness of ditch constructions as management practices for the regulation of water resources and facilitating the downstream transfer of sediment. Field observations and validation confirmed that Rndvic, which incorporates vegetation variable as a weight factor in the calculation of IC, yields more accurate and reliable maps of FSC than that of RI. This study holds far-reaching significance for water resources management and landscape sustainability within terrace-protected areas, providing invaluable insights for decision-makers.

Identification of important terraced visual landscapes based on a sensitivity-subjectivity preference matrix for agricultural cultural heritage in the southwestern china

Landscapes illustrating agricultural cultural heritage can serve as an important attraction to encourage tourism in support of rural revitalization in mountainous areas. These landscapes can aid in clarifying the regional scale of agricultural areas and identifying the visual landscape resources that play an important role in promoting the rational and sustainable use and development of resources in mountainous landscapes. Taking the terraced agricultural landscape with cultural resources in the southwestern mountainous region of China as the research object, a landscape visual sensitivity analysis was conducted on this region. This was done using GIS spatial analysis based on the data of relative slope, relative distance, and occurrence probability in the region and scenic beauty evaluation based on 176 questionnaires. Based on the importance-performance analysis, a sensitivity-subjectivity preference matrix of the visual landscape of having terraced agricultural and heritage resources in the southwestern mountainous area of China was constructed. Next, the visual landscape in the study area was classified into four types of areas, and corresponding landscape protection and planning suggestions were proposed. The study shows that the villages of Liushe, Qinglong, and Jiupang are in the “critical visual landscape area” and are evaluated as having high sensitivity-high preference evaluation; the villages of Baidu and Bailu are in the “natural development area” with low sensitivity-high preference. Furthermore, Zhanliu village is in the “priority improvement area” with high sensitivity-low preference; lastly, the villages of Jiulong, Liuzhai, and Liufu are in the “second priority improvement zone” with low sensitivity and preference. The findings of this study can provide a reference for determining the timing and direction of landscape development of agricultural heritage in the terraced mountainous areas of southwestern China; the landscape visual evaluation method employed here has implications for the identification of key areas in other mountainous landscapes.

EXPERIENCE OF EXPLORATION OF ARCHAEOLOGICAL SITES BY DRILLING METHOD (Based on Paleolithic Materials)

Over the past ten years, being in the Ukrainian Lower Palaeolithic Expedition of the National Academy of Sciences of Ukraine and in personal field research, various drilling methods exclusively for the optimization of the exploration process have been tested. All these field works were carried out in order to find Palaeolithic sites. However, our exploratory drilling techniques can be used to locate a wide range of archaeological sites. The first stage of exploratory drilling was carried out in 2012—2014 in the Luhansk region, in the middle reaches of the Siverskyi Donets river system. The second stage of such works began in 2015. It concerns the study of Lower Palaeolithic sites near Medzhybizh settlement, Khmelnytskyi district, Khmelnytskyi region. Based on the results of many years of experimental work we offer our method of exploratory drilling on light loamy-sandy soils. We consider that the optimal depths of exploratory drilling are from 1 to 2 m. According to the characteristics of the soil and used equipment we recommend using the exploratory drilling method to search first of all the Paleolithic-Bronze Age sites. The most appropriate for such works are the sod areas of river terraces, river floodplains and peat bogs, dunes or sod sand plates, forest areas. It is also possible to recommend exploratory drilling on agricultural land where the point drilling will not damage the cultivated areas and raise the issue of reimbursement for the fallout of archaeological exploration.&#x0D; The simple technology of reconnaissance works needs no high-skilled staff. The exploratory drilling is also to be recommended during the archaeological practice of first-year students of higher educational institutions. The progressive use of natural science methods in archaeological research is a reality today. The drilling method, as a technological component, can be applied as a non-invasive operation for the cultural layer, directly on the archaeological site. Drilling works can also be used in other types of research, as a method of selecting soil samples for the needs of geology, geophysics, geochemistry, and palaeobotany. Drilling can provide for the selection of single soil samples or complete soil columns for the description of an archaeological object using the methods of natural sciences.

Paddy Rice Phenological Mapping throughout 30-Years Satellite Images in the Honghe Hani Rice Terraces

The Honghe Hani Rice Terraces represent the coexistence between natural and cultural systems. Despite being listed as a World Heritage Site in 2013, certain natural and anthropogenic factors have changed land use/land cover, which has led to a reduction in the size of the paddy rice area. It is difficult to accurately assess these changes due to the lack of historical maps of paddy rice croplands with fine spatial resolution. Therefore, we integrated a random forest classifier and phenological information to improve mapping accuracy and stability. We then mapped the historical distribution of land use/land cover in the Honghe Hani Rice Terraces from 1989–1991 to 2019–2021 using the Google Earth Engine. Finally, we analyzed the driving forces of land use types in the Honghe Hani Rice Terraces. We found that: (1) forests, shrubs or grasslands, and other croplands could be discriminated from paddy rice during the flooding and transplanting period, and water bodies and buildings could also be discriminated from paddy rice during the growing and harvesting period. (2) Inputting phenological feature data improved mapping accuracy and stability compared with single phenological periods. (3) In the past thirty years, 10.651%, 8.810%, and 5.711% of paddy rice were respectively converted to forests, shrubs or grasslands, and other croplands in the Honghe Hani Rice Terraces. (4) Lower agricultural profits and drought led to problems in identifying the driving mechanisms behind paddy rice distribution changes. This study demonstrates that phenological information can improve the mapping accuracy of rice terraces. It also provides evidence for the change in the size of the rice terrace area and associated driving forces in Southwest China.

東京低地の埋没谷形状と地盤震動特性：上野-小岩測線での検討結果

To better understand how ground motion in the Tokyo Lowland is affected by the geological conditions in the shallow subsurface, we analyzed borehole logs and conducted microtremor observations along the Ueno-Koiwa survey line, which crosses the buried valley beneath the Tokyo Lowland. Remarkable peaks in the H/V spectra at ~1 Hz were found in the area of the lower buried terrace (buried flat surface 2), whereas the peaks at ~1 Hz are small in the area of the buried valley bottom with the thickest valley-filling post-Last Glacial Maximum (LGM) deposits. The sharp peaks around buried terrace 2 are generated by the large contrast in the physical properties of the soft, muddy post-LGM deposits and the underlying gravel bed, which suggests larger ground-motion amplification during an earthquake. The variation of the ground motion characteristics along the survey line obtained by microtremor observation is consistent with the distribution of seismic intensity during the 1923 Kanto Earthquake. It is, therefore, important to consider not only the thickness and physical properties of the post-LGM deposits during seismic hazard assessment, but also the total geological composition, including the Pleistocene strata below the post-LGM deposits.

Identification and Delineation of Broad-Base Agricultural Terraces in Flat Landscapes in Northeastern Oklahoma, USA

Broad-base agricultural terraces can be difficult to delineate in flat landscapes, particularly when covered by crops, due to subtle changes in elevation over relatively wide distances. In northeastern Oklahoma, these terraces are usually less than half a meter high and 15 to 20 m wide. The objective of this research was to develop and test a technique for identifying and classifying terraces using computer vision applied to terrain derivatives calculated from digital elevation models at five sites. We tested 38 terrain-derivative grid combinations or sets that represented 19 terrain characteristics, calculated from elevation models after two Gaussian smoothing strategies to provide some degree of generalization and a removal of excess noise. The best subsets achieved a 98% classification accuracy (kappa 0.96) and consisted of derivatives representing hydrology, morphometry, and visibility categories. Inaccuracies occurred primarily at the edges of some of the study sites, where agricultural fields bordered incised drainage areas where changes in elevation were similar to those for the terraces. Further study will elucidate the relationships between terrace “borrow” and “deposition” areas in the terrace areas and their relationships to yield and salinity issues. This work seeks to automate terrace identification for digital soil mapping on terraced fields for the improved delivery of soil information for resource conservation and land use.

Зонирование малых городов Иркутской области по степени опасности затопления

Methods of flooding zones identification using as satellite space images as digital elevation model in the QGIS geographic information system are considered. It has been determined that the digital elevation model is most effective method. It allows to more accurately identify the flooding zone boundary according to the elevation marks of the highest water level at the hydrological station. For studying the floods risk the small towns in the Angara River basin in Irkutsk region were selected (Tulun, Nizhneudinsk and Biryusinsk), which located on the floodplain areas of the Iya, Uda and Biryusa Rivers. Biryusinsk is subject to less flooding and consequences due to the location of the town on elevated areas of the right-bank terraces of the Biryusa River valley. Zoning of “Tulun town”, “Nizhneudinsk town” and “Biryusinsk town” according to the flood risk degree was carried out. According to relief elevation marks the four zones have been defined for each territory, which characterized by different degrees of flooding hazard (high hazard, medium hazard, low hazard and no hazard zone). An analysis of the main causes, as well as the structure of the flood zone during the catastrophic rain flood of 2019 in the cities of Tulun and Nizhneudinsk was carried out. He showed that, along with hydroclimatic factors (intense and abundant rainfall, high previous moisture content of watersheds), a significant role in the formation of great damage from floods was played by high population, economic development and development features of flooding areas of the Iya and Uda river valleys. The floods damage in Biryusinsk is less, despite the frequent observation of water levels above the critical level due to the city location on elevated area of the right-bank terraces of the Biryusa river.

Mapping groundwater vulnerability using drastic method

Preventive management and protection of groundwater were to create a groundwater vulnerability map. This map provided information distribution on the level of vulnerability to groundwater contamination in an area. The impact made considered in making regional decisions to create a sustainable development framework. The DRASTIC method is an instrument for evaluating the vulnerability of groundwater pollution. The DRASTIC methods can use evaluate vulnerabilities of groundwater contamination which seven parameters: the depth of the groundwater table (D), rainPL (R), aquifer media (A), soil texture (S), topography (T), the influence of unsaturated zones (I), and hydraulic conductivity (C). The additional parameter is the use of land resulting from vulnerability. The parameter data will be poured into a map using ArcGIS and analyzed using the DRASTIC rating index. Eight attributes are included in the modified DRASTIC model, including hydraulic conductivity of the aquifer, topography, impact of the vadose zone, depth to water table, net recharge, aquifer media, soil media, and aquifer media. In a GIS system, these layers were combined using the Raster Calculator tool. The modelx was further validated using fifteen groundwater composite samples that were also gathered. Based on the results of the analysis, groundwater vulnerability in Terjun’s landfill from the five parameters, the value of the DRASCTIC index is 137 which indicates the vulnerability of groundwater is at medium/moderate. Aquifers next to floodplain areas are very sensitive, whereas those next to terrace areas are less vulnerable, according to the results. The model's findings confirm that the topography, soil media, and aquifer depth indicated the strongest correlations with vulnerability. A positive association between the vulnerability classes and the three groundwater quality measures electrical conductivity was also found during the validation of the final DRASTIC map. Although the levels of contamination at this time are below acceptable bounds, the possibility of additional contamination cannot be completely eliminated and is really rather plausible.

Temp-Spatial Heterogeneity of Water Recharge and Its Stable Mechanisms of the Mountainous Rice Terraces in East Asia Monsoon Region

The paddy field water recharge system and the mechanism of its stability are key scientific issues related to reducing the threat to global food security and enhancing the well-being of humans. In this study, we sampled the field water, precipitation, and groundwater in the Hani terrace areas and measured the values of hydrogen and oxygen stable isotopes. The results indicated that precipitation and groundwater were the main sources of terrace water recharge in the Hani terrace area. Spatially, the terrace areas were divided into rain-fed terraces, which were mainly recharged by precipitation, and spring-fed terraces, where groundwater was the primary source of recharge. Temporally, there were two different recharge periods: the rain-fed season (&gt;70% recharge from precipitation) and the spring-fed season (&gt;30% recharge from groundwater). The temporally alternating recharge periods of the spring-fed and rain-fed seasons and the interconnected spatial distribution of rain-fed and spring-fed types were essential to maintain stable water sources in the Hani terraces. Meanwhile, the spatial heterogeneity of groundwater recharge and the timing of agricultural cultivation adjusted the system to some extent. Rice cultivation will be sustainable if the changes in monsoonal precipitation due to global climate change align with the anthropogenic agricultural cultivation cycle, including land preparation, planting, growing, and harvesting. This is the key reason that the mountainous rice cultivation systems of the Hani terraces have lasted for thousands of years under the influence of the East Asian monsoon.

Real-Time Groundwater Dynamics Verification in the Embankment’s Substrate during the Transition of a Flood Wave

The scope of the presented research included real-time verification of groundwater dynamics in the zone of the filled erosion channel (crevasses) and in the non-transformed zone of the floodplain area during the transition of a flood wave in the river channel. The technical goal was to provide data for the calibration and verification of mathematical model of groundwater flow. For this purpose, automatic recorders of groundwater level and electrical conductivity were installed in the zones selected earlier with the use of DEM. The measurements were carried out in 3 series during the passage of the flood wave. The obtained results indicate that in the zone of the untransformed terrace, the ascension of the water level between embankments causes the immediate propagation of pressure in the aquifer, while the filtration process itself is considerably limited, whereas the filled crevasse troughs constitute paths of privileged filtration, in particular in the proximal part of the floodplain. The appearance of water with elevated conductivity in the area of the crevasse proves the cyclicality of changes in flow directions, depending on the water level between embankments. The proposed methodology can be a valuable tool in the process of the geotechnical assessment of the construction substrate in the area of flood terraces in the lowland river. The zones with increased water conductivity parameters located near the river channel are also a reasonable place for the construction of coastal water intakes of the Riverbank filtration (RBF) type.

Characterizing the rill erosion process from eroded morphology and sediment connectivity on purple soil slope with upslope earthen dike terraces

Rills are critical venues for the transport of eroded sediments along hillslopes. The sediment transport efficiency and connectivity within hillslopes are affected by the spatiotemporal evolution of rill erosion and morphology. However, the effect of upslope sediment-laden inflow on rill erosion and connectivity remains unclear. This study investigated the variation in rill erosion from the eroded morphology and sediment connectivity using flume scouring experiments. Upslope sediment-laden inflow was simulated considering the upslope terrace areas of 0.15, 0.30, and 0.45 m2 and an upslope inflow of 6 L min−1. The quantity and cross-sectional depth of rills gradually decreased with increasing upslope terrace area. The cross-sectional morphology of rills changed from being V-shaped to U-shaped in the rill erosion process. All of the mean values of the morphological parameters gradually decreased with increasing upslope terrace area, in contrast to the width-depth ratio (Rw/d) and rill density (ρ), which both initially increased and then decreased. The average length, width, and depth of rills were smaller under an upslope terrace area of 0.45 m2 than those under an upslope terrace area of 0.15 m2; they decreased by 2.78 %, 20.67 %, and 33.68 %, respectively. Soil and water loss induced by rill erosion decreased with increasing upslope terrace area. Rills, as major venues for sediment transport on hillslopes, exhibited a higher sediment connectivity (IC) than that observed in interrill areas under the different upslope terrace areas. Rill development resulted in higher erosion between the upslope and downslope parts within rill channels. The variations in Rw/d and ρ were significantly correlated with runoff and eroded sediment yield, which could be used to estimate the rill erosion process under different upslope terrace areas.