An effective damage test method based on a marker-based watershed algorithm with gray control(MWGC) is proposed to study the properties of damage induced by near-field laser irradiation for large-aperture laser facili...An effective damage test method based on a marker-based watershed algorithm with gray control(MWGC) is proposed to study the properties of damage induced by near-field laser irradiation for large-aperture laser facilities.Damage tests were performed on fused silica samples and information on the size of damage sites was obtained by this new algorithm,which can effectively suppress the issue of over-segmentation of images resulting from non-uniform illumination in darkfield imaging.Experimental analysis and results show that the lateral damage growth on the exit surface is exponential,and the number of damage sites decreases sharply with damage site size in the damage site distribution statistics.The average damage growth coefficients fitted according to the experimental results for Corning-7980 and Heraeus-Suprasil312 samples at 351 nm are 1.10 ± 0.31 and 0.60 ± 0.09,respectively.展开更多
Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researchin...Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researching geohazard,from regional to individual scale.The methodology includes the establishment of geological chain inventories,discrimination of geohazard chain modes,analyses of dynamics and dam breaches,and risk assessments.The following results were obtained:(1)In the downstream of Yarlung Zangbo River,175 sites were identified as high-risk for river blockage disasters,indicating the development of watershed geohazards.Five geohazard chain modes were summarized by incorporating geomorphological characteristics,historical events,landslide zoning,and materials.The risk areas of typical hazard were identified and assessed using InSAR data.(2)Glacier-related watershed geohazard chains are significantly different from traditional landslides.A detailed inversion analysis was conducted on the massive rock-ice avalanche in the Sedongpu gully in 2021.This particular event lasted roughly 300 seconds,with a maximum flow velocity of 77.2 m/s and a maximum flow height of 93 meters.By scrutinizing the dynamic processes and mechanical characteristics,mobility stages and phase transitions can be divided into four stages.(3)Watershed geohazard chains tend to block rivers.The peak breach discharge of the Yigong Landslide reached 12.4×10^(4) m^(3)/s,which is 36 times the volume of the seasonal flood discharge in the Yigong River.Megafloods caused by landslide dam breaches have significantly shaped the geomorphology.This study offers insights into disaster patterns and the multistaged movement characteristics of glacier-related watershed geohazard chains,providing a comprehensive method for investigations and assessments in glacial regions.展开更多
Human well-being and livelihoods depend on natural ecosystem services(ESs).Following the increment of population,ESs have been deteriorated over time.Ultimately,land use/land cover(LULC)changes have a profound impact ...Human well-being and livelihoods depend on natural ecosystem services(ESs).Following the increment of population,ESs have been deteriorated over time.Ultimately,land use/land cover(LULC)changes have a profound impact on the change of ecosystem.The primary goal of this study is to determine the impacts of LULC changes on ecosystem service values(ESVs)in the upper Gilgel Abbay watershed,Ethiopia.Changes in LULC types were studied using three Landsat images representing 1986,2003,and 2021.The Landsat images were classified using a supervised image classification technique in Earth Resources Data Analysis System(ERDAS)Imagine 2014.We classified ESs in this study into four categories(including provisioning,regulating,supporting,and cultural services)based on global ES classification scheme.The adjusted ESV coefficient benefit approach was employed to measure the impacts of LULC changes on ESVs.Five LULC types were identified in this study,including cultivated land,forest,shrubland,grassland,and water body.The result revealed that the area of cultivated land accounted for 64.50%,71.50%,and 61.50%of the total area in 1986,2003,and 2021,respectively.The percentage of the total area covered by forest was 9.50%,5.90%,and 14.80%in 1986,2003,and 2021,respectively.Result revealed that the total ESV decreased from 7.42×10^(7) to 6.44×10^(7) USD between 1986 and 2003.This is due to the expansion of cultivated land at the expense of forest and shrubland.However,the total ESV increased from 6.44×10^(7) to 7.76×10^(7) USD during 2003-2021,because of the increment of forest and shrubland.The expansion of cultivated land and the reductions of forest and shrubland reduced most individual ESs during 1986-2003.Nevertheless,the increase in forest and shrubland at the expense of cultivated land enhanced many ESs during 2003-2021.Therefore,the findings suggest that appropriate land use practices should be scaled-up to sustainably maintain ESs.展开更多
The geomorphic evolution of the Xindiangou small watershed on the Loess Plateau in China is influenced by many factors,resulting in very complex evolutionary characteristics of erosion,morphology,and development.Since...The geomorphic evolution of the Xindiangou small watershed on the Loess Plateau in China is influenced by many factors,resulting in very complex evolutionary characteristics of erosion,morphology,and development.Since 1952,a number of soil and water conservation projects have been implemented in the watershed,especially the largescale project of returning farmland to forest and grass since 1999,which has significant impact on the erosion characteristics of the loess.This paper takes a unique perspective of the watershed geomorphic system and its watershed geomorphic entropy(WGE)and clarifies the geomorphic erosion characteristics of the Xindiangou small watershed.The results show that in the past 45 years,the entropy change of WGE of this watershed has generally shown the characteristics of entropy decrease and local entropy increase.The watershed is dominated by erosion in general,but due to the large-scale implementation of various soil and water conservation projects,especially the Project of Returning Farmland to Forests and Grasslands(RFFG),the landform erosion intensity has been greatly reduced and local increase in the entropy change of WGE has appeared.These projects have achieved good ecological effects after 11 years of implementation.展开更多
Land use and precipitation are two major factors affecting phosphorus(P)pollution of watershed runoff.However,molecular characterization of dissolved organic phosphorus(DOP)in runoff under the joint influences of land...Land use and precipitation are two major factors affecting phosphorus(P)pollution of watershed runoff.However,molecular characterization of dissolved organic phosphorus(DOP)in runoff under the joint influences of land use and precipitation remains limited.This study used Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)to study the molecular characteristics of DOP in a typical P-polluted watershed with spatially variable land use and precipitation.The results showed that low precipitation and intense human activity,including phosphate mining and associated industries,resulted in the accumulation of aliphatic DOP compounds in the upper reaches,characterized by low aromaticity and low biological stability.Higher precipitation and widespread agriculture in the middle and lower reaches resulted in highly unsaturated DOP compounds with high biological stability constituting a higher proportion,compared to in the upper reaches.While,under similar precipitation,more aliphatic DOP compounds characterized by lower aromaticity and higher saturation were enriched in the lower reaches due to more influence from urban runoff relative to the middle reaches.Photochemical and/or microbial processes did result in changes in the characteristics of DOP compounds during runoff processes due to the prevalence of low molecular weight and low O/C bioavailable aliphatic DOP molecules in the upper reaches,which were increasingly transformed into refractory compounds from the upper tomiddle reaches.The results of this study can increase the understanding of the joint impacts of land use and precipitation on DOP compounds in watershed runoff.展开更多
This study evaluates pesticide contamination in groundwater downstream of the Kaddoussa Dam(Guir watershed,Morocco)and investigates the influence of agricultural activities on water quality.Nine sampling stations were...This study evaluates pesticide contamination in groundwater downstream of the Kaddoussa Dam(Guir watershed,Morocco)and investigates the influence of agricultural activities on water quality.Nine sampling stations were strategicallyselected during November 2023(post-agricultural season)to analyze spatial patterns of 18 pesticide residues:7 organophosphorusand 11 organochlorines.Identification and quantification were performed via gas chromatography method,targetingboth compound classes.Key findings reveal moderate yet localized contamination.The total concentration of organophosphoruspesticides(ΣPOPs)ranged from 0μg/L(S8)to 0.191μg/L(S4),with peak concentrations at stations S3(0.190μg/L)and S4(0.191μg/L),correlating spatially with intensive agricultural zones.Otherwise,the total concentration oforganochlorine pesticides(ΣPOCs)showed lower levels(0-0.060μg/L),with maxima at S4 linked to endosulfan and HCHisomers.Notably,none of the detected organochlorine concentrations exceeded 0.06μg/L,indicating relatively low levels ofcontamination.Central stations(S2-S6)exhibited co-occurrence of both pesticide groups,dominated by organophosphoruspesticides(0.135-0.191μg/L),while peripheral sites(S1,S7,S8,S9)displayed negligible or undetectable residues.Despitesub-regulatory thresholds,the persistent detection of pesticides underscores ecological and public health risks,particularlyin arid regions with heightened vulnerability due to limited healthcare access and water scarcity.Even at low concentrations,organophosphorus and organochlorine pesticides pose significant threats to aquatic ecosystems through bioaccumulation,while also presenting acute health risks to farmworkers and local communities dependent on contaminated groundwater.This study highlights the urgent need for integrated pesticide management strategies to mitigate long-term environmentaland socio-economic impacts in agriculturally intensive,water-stressed regions.展开更多
Pingquan City,the origin of five rivers,serves as the core water conservation zone for the Beijing-Tianjin-Hebei region and exemplifies the characteristics of small watersheds in hilly areas.In recent years,excessive ...Pingquan City,the origin of five rivers,serves as the core water conservation zone for the Beijing-Tianjin-Hebei region and exemplifies the characteristics of small watersheds in hilly areas.In recent years,excessive mining and intensified human activities have severely disrupted the local ecosystem,creating an urgent need for ecological vulnerability assessment to enhance water conservation functions.This study employed the sensitivity-resilience-pressure model,integrating various data sources,including regional background,hydro-meteorological data,field investigations,remote sensing analysis,and socio-economic data.The weights of the model indices were determined using an entropy weighting model that combines principal component analysis and the analytic hierarchy process.Using the ArcGIS platform,the spatial distribution and driving forces of ecological vulnerability in 2020 were analyzed,providing valuable insights for regional ecological restoration.The results indicated that the overall Ecological Vulnerability Index(EVI)was 0.389,signifying moderate ecological vulnerability,with significant variation between watersheds.The Daling River Basin had a high EVI,with ecological vulnerability primarily in levels IV and V,indicating high ecological pressure,whereas the Laoniu River Basin had a low EVI,reflecting minimal ecological pressure.Soil type was identified as the primary driving factor,followed by elevation,temperature,and soil erosion as secondary factors.It is recommended to focus on key regions and critical factors while conducting comprehensive monitoring and assessment to ensure the long-term success of ecological management efforts.展开更多
Understanding the active tectonic processes in the Nandakini Watershed is imperative for evaluating geological hazards and seismic risks,as well as for informing land-use planning and natural resource management strat...Understanding the active tectonic processes in the Nandakini Watershed is imperative for evaluating geological hazards and seismic risks,as well as for informing land-use planning and natural resource management strategies in the region.Tectonic geomorphology serves as a vital tool for characterizing recent tectonic movements.This research employs GIS techniques to elucidate tectonic activity and its influence on drainage patterns in the Nandakini Watershed,utilizing morphometric parameters derived from SRTM DEM data.Morphometric indices are employed to assess the tectonic movement within drainage basins,capturing both areal and linear factors such as drainage density,texture,circulatory and bifurcation ratios,and stream length ratios.The linear and areal morphometric indices are categorized into three classes representing varying degrees of active tectonic activity.These classifications are then utilized to compute the relative active tectonic index(IRAT).In addition,geomorphic parameters include hypsometric integral,stream length-gradient index,normalized steepness index,chi gradient index,and swath profiles.The majority of the studied region is in an extremely high to moderately active tectonic zone.Large-scale faults and thrusts within the basins are closely correlated with these zones that have been identified.The integrated methodology of GIS-based morphometric analysis and geomorphic study enables the identification of deformed landforms associated with ongoing tectonic activity.Furthermore,these results offer valuable insights for informing watershed management strategies and promoting sustainable land use planning initiatives.展开更多
Soil erosion in the Hare watershed led to significant land degradation,water pollution,and reduced agricultural productivity.Despite its effects,very few researchers have used combined morphometric and RUSLE model tec...Soil erosion in the Hare watershed led to significant land degradation,water pollution,and reduced agricultural productivity.Despite its effects,very few researchers have used combined morphometric and RUSLE model techniques to quantify soil erosion and thereby prioritize impacted areas.This work used an automated GIS-based tool(SWPT)to prioritize crucial areas based on topohydrological and morphometric factors and predict soil loss in sub-watersheds using the RUSLE model.Land use/cover data were obtained from Landsat imagery,while slope and morphometric information were extracted from digital elevation data with a resolution of 12.5 m.Soil erodibility was determined using Ethiopian soil maps,and rainfall erosivity was computed using meteorological data.An average annual soil loss of 49 t ha-1 yr-1 was observed in the Hare watershed.Sub-watershed 11 was found to be the most affected,with an average annual soil loss of 85.12 t ha-1 yr-1and a compound parameter value(CPV)of 0.059.Subwatershed 17 has the least amount of soil loss,with 3.67t ha-1 yr-1 and a CPV of 1.32.The study emphasizes the usefulness of integrating RUSLE and morphometric analysis for soil and water conservation planning,suggesting a variety of modeling tools in data-sparse locations to quantify and prioritize erosion-prone areas.展开更多
Accurate measurement of bean particle size is essential for automated grading and quality control in agricultural processing.However,existing image segmentation methods often suffer from low efficiency,over-segmentati...Accurate measurement of bean particle size is essential for automated grading and quality control in agricultural processing.However,existing image segmentation methods often suffer from low efficiency,over-segmentation,and high computational cost.We proposed a distancegradient dual constrained watershed algorithm for precise segmentation and measurement of bean particles.The method integrated distance transform-based seed extraction with gradient-constrained flooding,effectively suppressing noise-induced region fragmentation and improving the separation of adherent particles.An experimental platform was constructed using an industrial camera and an image-processing pipeline to evaluate performance.Compared with the conventional watershed algorithm,the proposed method improves segmentation accuracy by 7.2%and reduces the mean particle size error by 27.8%(0.13 mm,representing a relative error of 2.4%).Validation on three soybean varieties confirmed the robustness and generalizability of the approach.The results indicated that the proposed algorithm provided an efficient and accurate technique for agricultural particle size analysis,offering potential for integration into practical low-cost inspection systems.展开更多
Under the current global climate change background,the response of soil heavy metals in the Qinghai Tibet Plateau basin to the intensification of climate change is still unclear,leading to the intensification of heavy...Under the current global climate change background,the response of soil heavy metals in the Qinghai Tibet Plateau basin to the intensification of climate change is still unclear,leading to the intensification of heavy metal migration in the watershed.We selected cadmium(Cd)in soils of the Taohe River Basin on the Tibetan Plateau as the study object,and established a heavy metal migration simulation model based on the Soil and Water Assessment Tool(SWAT)to estimate the impact of climate change on Cd migration in the basin.The results indicated that the drought indexes and precipitation were the main determinants of the changes in Cd migration in the basin.The multi–scale drought indexes indicated that the optimal time scale for evaluating the effect of drought on Cd migration in the watershed was 3 months.Higher migration rates were apparent in summer and autumn(wet season)than in winter and spring(dry season).Spring precipitation was significantly and positively correlated with the migration of elemental Cd,and the Standardized Precipitation Index(SPI)3 drought index was significantly and positively correlated with Cd migration in summer,autumn,and winter.For every 5%increase in precipitation,Cd migration rates increased by 3.55%,0.46%,0.15%,and 0.12%in spring,summer,autumn,and winter,respectively.For every 5%decrease in precipitation,Cd migration rates decreased by 0.11%,0.12%,0.14%,and 0.13%in spring,summer,autumn,and winter,respectively.The risk of Cd transport in soil continues to increase under future climate change scenarios.展开更多
Water scarcity and environment deterioration have become main constraints to sustainable economic and social development.Scientifically assessing Water Resources Carrying Capacity(WRCC)is essential for the optimal all...Water scarcity and environment deterioration have become main constraints to sustainable economic and social development.Scientifically assessing Water Resources Carrying Capacity(WRCC)is essential for the optimal allocation of regional water resources.The hilly area at the northern foot of Yanshan Mountains is a key water conservation zone and an important water source for Beijing,Tianjin and Hebei.Grasping the current status and temporal trends of water quality and WRCC in representative small watersheds within this region is crucial for supporting rational water resources allocation and environment protection efforts.This study focuses on Pingquan City,a typical watershed in northern Hebei Province.Firstly,evaluation index systems for surface water quality,groundwater quality and WRCC were estab-lished based on the Pressure-State-Response(PSR)framework.Then,comprehensive evaluations of water quality and WRCC at the sub-watershed scale were conducted using the Varying Fuzzy Pattern Recogni-tion(VFPR)model.Finally,the rationality of the evaluation results was verified,and future scenarios were projected.Results showed that:(1)The average comprehensive evaluation scores for surface water and groundwater quality in the sub-watersheds were 1.44 and 1.46,respectively,indicating that both met the national Class II water quality standard and reflected a high-quality water environment.(2)From 2010 to 2020,the region's WRCC steadily improved,with scores rising from 2.99 to 2.83 and an average of 2.90,suggesting effective water resources management in Pingquan City.(3)According to scenario-based predic-tion,WRCC may slightly decline between 2025 and 2030,reaching 2.92 and 2.94,respectively,relative to 2020 levels.Therefore,future efforts should focus on strengthening scientific management and promoting the efficient use of water resources.Proactive measures are necessary to mitigate emerging contradiction and ensure the long-term stability and sustainability of the water resources system in the region.The evalua-tion system and spatiotemporal evolution patterns proposed in this study can provide a scientific basis for refined water resource management and ecological conservation in similar hilly areas.展开更多
The Jiangxi province was divided into seven parts according to the concept of watershed,namely Poyang lake area,Fuhe,Xinjiang,Ganjiang,Xiuhe,Raohe and other river watersheds.The ecological supply and demands status of...The Jiangxi province was divided into seven parts according to the concept of watershed,namely Poyang lake area,Fuhe,Xinjiang,Ganjiang,Xiuhe,Raohe and other river watersheds.The ecological supply and demands status of the former six parts from 2000 to 2006 was computed based on the ecological footprint model and a spatiotemporal comparative analysis to them was conducted.The result showed that:①all the studied areas had an increasing ecological deficit and they were in the status of unsustainable development;② the arable land footprint's demand were about 80% of their total footprint's demand respectively,so it was of great significance to protect and exploit arable land resources scientifically;③ the ecological deficit of grassland and forest resources can not be ignored.展开更多
A thorough analysis on its natural environment as well as social economic status of the hilly-gullied loess region is presented. A small watershed, the dominant landscape unit of the region, has been singled out for f...A thorough analysis on its natural environment as well as social economic status of the hilly-gullied loess region is presented. A small watershed, the dominant landscape unit of the region, has been singled out for further and specific study on landscape pattern and function, its social and economic distinctions. The authors proposed several principles based on its eco-economic background study, which includes water balance and efficient use principle, co-development of grass and agro-forestry principle, location optimization principle. Integrated with detailed analysis of a small watershed, an eco-productive paradigm for the loess land's development based on a small watershed scale was worked out. It consists of circle pattern with villages at core for high efficient agriculture production, hierarchical pattern along the slope for eco-economic development, point-axis pattern for commodity production and circulation in small watersheds and core-margin pattern for exchanges among watersheds.展开更多
The changes of grassland landscape pattern in Qinghai Lake watershed from 1977 to 2000 were studied by adopting 3S technologies and landscape pattern analysis.The results showed that the amount of grassland landscape ...The changes of grassland landscape pattern in Qinghai Lake watershed from 1977 to 2000 were studied by adopting 3S technologies and landscape pattern analysis.The results showed that the amount of grassland landscape patch reduced,landscape fragmentation and resolution decreased,but average patch area and fractal dimension increased;through analyzing the landscape change of counties in Qinghai Lake watershed,the grassland landscape structure of Tianjun,Gangcha and Haiyan counties showed a similar change trend;but in Gonghe County grassland patch amount,landscape fragmentation and resolution increased,average patch area decreased,that is,the grassland landscape structure in this county showed a different trend.展开更多
Xiayun Township watershed in the upper reaches of Hongfeng Lake is selected to study the relationship between stream grade and water quality.Turbidity and ammonium nitrogen concentration are obviously related to the s...Xiayun Township watershed in the upper reaches of Hongfeng Lake is selected to study the relationship between stream grade and water quality.Turbidity and ammonium nitrogen concentration are obviously related to the stream grade,generally speaking,are positively correlated,and the water quality is degrading from the upper reaches to the lower reaches.In the future,the influence of different land use types on the water quality should be fully analyzed on the basis of enhancing the water quality monitoring to provide supports for effectively controlling non-point source pollutions and treating the water environment of Hongfeng Lake.展开更多
文摘An effective damage test method based on a marker-based watershed algorithm with gray control(MWGC) is proposed to study the properties of damage induced by near-field laser irradiation for large-aperture laser facilities.Damage tests were performed on fused silica samples and information on the size of damage sites was obtained by this new algorithm,which can effectively suppress the issue of over-segmentation of images resulting from non-uniform illumination in darkfield imaging.Experimental analysis and results show that the lateral damage growth on the exit surface is exponential,and the number of damage sites decreases sharply with damage site size in the damage site distribution statistics.The average damage growth coefficients fitted according to the experimental results for Corning-7980 and Heraeus-Suprasil312 samples at 351 nm are 1.10 ± 0.31 and 0.60 ± 0.09,respectively.
基金supported by the National Natural Science Foundation of China(Nos.U2244227,U2244226,42177172)the National Key R&D Program of China(No.2022YFC3004301)China Geological Survey Project(No.DD20230538)。
文摘Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researching geohazard,from regional to individual scale.The methodology includes the establishment of geological chain inventories,discrimination of geohazard chain modes,analyses of dynamics and dam breaches,and risk assessments.The following results were obtained:(1)In the downstream of Yarlung Zangbo River,175 sites were identified as high-risk for river blockage disasters,indicating the development of watershed geohazards.Five geohazard chain modes were summarized by incorporating geomorphological characteristics,historical events,landslide zoning,and materials.The risk areas of typical hazard were identified and assessed using InSAR data.(2)Glacier-related watershed geohazard chains are significantly different from traditional landslides.A detailed inversion analysis was conducted on the massive rock-ice avalanche in the Sedongpu gully in 2021.This particular event lasted roughly 300 seconds,with a maximum flow velocity of 77.2 m/s and a maximum flow height of 93 meters.By scrutinizing the dynamic processes and mechanical characteristics,mobility stages and phase transitions can be divided into four stages.(3)Watershed geohazard chains tend to block rivers.The peak breach discharge of the Yigong Landslide reached 12.4×10^(4) m^(3)/s,which is 36 times the volume of the seasonal flood discharge in the Yigong River.Megafloods caused by landslide dam breaches have significantly shaped the geomorphology.This study offers insights into disaster patterns and the multistaged movement characteristics of glacier-related watershed geohazard chains,providing a comprehensive method for investigations and assessments in glacial regions.
文摘Human well-being and livelihoods depend on natural ecosystem services(ESs).Following the increment of population,ESs have been deteriorated over time.Ultimately,land use/land cover(LULC)changes have a profound impact on the change of ecosystem.The primary goal of this study is to determine the impacts of LULC changes on ecosystem service values(ESVs)in the upper Gilgel Abbay watershed,Ethiopia.Changes in LULC types were studied using three Landsat images representing 1986,2003,and 2021.The Landsat images were classified using a supervised image classification technique in Earth Resources Data Analysis System(ERDAS)Imagine 2014.We classified ESs in this study into four categories(including provisioning,regulating,supporting,and cultural services)based on global ES classification scheme.The adjusted ESV coefficient benefit approach was employed to measure the impacts of LULC changes on ESVs.Five LULC types were identified in this study,including cultivated land,forest,shrubland,grassland,and water body.The result revealed that the area of cultivated land accounted for 64.50%,71.50%,and 61.50%of the total area in 1986,2003,and 2021,respectively.The percentage of the total area covered by forest was 9.50%,5.90%,and 14.80%in 1986,2003,and 2021,respectively.Result revealed that the total ESV decreased from 7.42×10^(7) to 6.44×10^(7) USD between 1986 and 2003.This is due to the expansion of cultivated land at the expense of forest and shrubland.However,the total ESV increased from 6.44×10^(7) to 7.76×10^(7) USD during 2003-2021,because of the increment of forest and shrubland.The expansion of cultivated land and the reductions of forest and shrubland reduced most individual ESs during 1986-2003.Nevertheless,the increase in forest and shrubland at the expense of cultivated land enhanced many ESs during 2003-2021.Therefore,the findings suggest that appropriate land use practices should be scaled-up to sustainably maintain ESs.
基金funded by the National Natural Science Foundation of China(Grant No.42271417)the financial support from the National Natural Science Foundation of China。
文摘The geomorphic evolution of the Xindiangou small watershed on the Loess Plateau in China is influenced by many factors,resulting in very complex evolutionary characteristics of erosion,morphology,and development.Since 1952,a number of soil and water conservation projects have been implemented in the watershed,especially the largescale project of returning farmland to forest and grass since 1999,which has significant impact on the erosion characteristics of the loess.This paper takes a unique perspective of the watershed geomorphic system and its watershed geomorphic entropy(WGE)and clarifies the geomorphic erosion characteristics of the Xindiangou small watershed.The results show that in the past 45 years,the entropy change of WGE of this watershed has generally shown the characteristics of entropy decrease and local entropy increase.The watershed is dominated by erosion in general,but due to the large-scale implementation of various soil and water conservation projects,especially the Project of Returning Farmland to Forests and Grasslands(RFFG),the landform erosion intensity has been greatly reduced and local increase in the entropy change of WGE has appeared.These projects have achieved good ecological effects after 11 years of implementation.
基金supported by the Three Gorges Corporation (No.HBHB2023018)the Project of Hubei Provincial Key Research and Development (No.2022BCA074)the National Key Research and Development Program of China (No.2022YFC3705002).
文摘Land use and precipitation are two major factors affecting phosphorus(P)pollution of watershed runoff.However,molecular characterization of dissolved organic phosphorus(DOP)in runoff under the joint influences of land use and precipitation remains limited.This study used Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)to study the molecular characteristics of DOP in a typical P-polluted watershed with spatially variable land use and precipitation.The results showed that low precipitation and intense human activity,including phosphate mining and associated industries,resulted in the accumulation of aliphatic DOP compounds in the upper reaches,characterized by low aromaticity and low biological stability.Higher precipitation and widespread agriculture in the middle and lower reaches resulted in highly unsaturated DOP compounds with high biological stability constituting a higher proportion,compared to in the upper reaches.While,under similar precipitation,more aliphatic DOP compounds characterized by lower aromaticity and higher saturation were enriched in the lower reaches due to more influence from urban runoff relative to the middle reaches.Photochemical and/or microbial processes did result in changes in the characteristics of DOP compounds during runoff processes due to the prevalence of low molecular weight and low O/C bioavailable aliphatic DOP molecules in the upper reaches,which were increasingly transformed into refractory compounds from the upper tomiddle reaches.The results of this study can increase the understanding of the joint impacts of land use and precipitation on DOP compounds in watershed runoff.
文摘This study evaluates pesticide contamination in groundwater downstream of the Kaddoussa Dam(Guir watershed,Morocco)and investigates the influence of agricultural activities on water quality.Nine sampling stations were strategicallyselected during November 2023(post-agricultural season)to analyze spatial patterns of 18 pesticide residues:7 organophosphorusand 11 organochlorines.Identification and quantification were performed via gas chromatography method,targetingboth compound classes.Key findings reveal moderate yet localized contamination.The total concentration of organophosphoruspesticides(ΣPOPs)ranged from 0μg/L(S8)to 0.191μg/L(S4),with peak concentrations at stations S3(0.190μg/L)and S4(0.191μg/L),correlating spatially with intensive agricultural zones.Otherwise,the total concentration oforganochlorine pesticides(ΣPOCs)showed lower levels(0-0.060μg/L),with maxima at S4 linked to endosulfan and HCHisomers.Notably,none of the detected organochlorine concentrations exceeded 0.06μg/L,indicating relatively low levels ofcontamination.Central stations(S2-S6)exhibited co-occurrence of both pesticide groups,dominated by organophosphoruspesticides(0.135-0.191μg/L),while peripheral sites(S1,S7,S8,S9)displayed negligible or undetectable residues.Despitesub-regulatory thresholds,the persistent detection of pesticides underscores ecological and public health risks,particularlyin arid regions with heightened vulnerability due to limited healthcare access and water scarcity.Even at low concentrations,organophosphorus and organochlorine pesticides pose significant threats to aquatic ecosystems through bioaccumulation,while also presenting acute health risks to farmworkers and local communities dependent on contaminated groundwater.This study highlights the urgent need for integrated pesticide management strategies to mitigate long-term environmentaland socio-economic impacts in agriculturally intensive,water-stressed regions.
基金supported by the project of China Geological Survey(No.DD20220954)Open Funding Project of the Key Laboratory of Groundwater Sciences and Engineering,Ministry of Natural Resources(No.SK202301-4)+1 种基金Open Foundation of the Key Laboratory of Coupling Process and Effect of Natural Resources Elements(No.2022KFKTC009)Yanzhao Shanshui Science and Innovation Fund of Langfang Integrated Natural Resources Survey Center,China Geological Survey(No.YZSSJJ202401-001).
文摘Pingquan City,the origin of five rivers,serves as the core water conservation zone for the Beijing-Tianjin-Hebei region and exemplifies the characteristics of small watersheds in hilly areas.In recent years,excessive mining and intensified human activities have severely disrupted the local ecosystem,creating an urgent need for ecological vulnerability assessment to enhance water conservation functions.This study employed the sensitivity-resilience-pressure model,integrating various data sources,including regional background,hydro-meteorological data,field investigations,remote sensing analysis,and socio-economic data.The weights of the model indices were determined using an entropy weighting model that combines principal component analysis and the analytic hierarchy process.Using the ArcGIS platform,the spatial distribution and driving forces of ecological vulnerability in 2020 were analyzed,providing valuable insights for regional ecological restoration.The results indicated that the overall Ecological Vulnerability Index(EVI)was 0.389,signifying moderate ecological vulnerability,with significant variation between watersheds.The Daling River Basin had a high EVI,with ecological vulnerability primarily in levels IV and V,indicating high ecological pressure,whereas the Laoniu River Basin had a low EVI,reflecting minimal ecological pressure.Soil type was identified as the primary driving factor,followed by elevation,temperature,and soil erosion as secondary factors.It is recommended to focus on key regions and critical factors while conducting comprehensive monitoring and assessment to ensure the long-term success of ecological management efforts.
文摘Understanding the active tectonic processes in the Nandakini Watershed is imperative for evaluating geological hazards and seismic risks,as well as for informing land-use planning and natural resource management strategies in the region.Tectonic geomorphology serves as a vital tool for characterizing recent tectonic movements.This research employs GIS techniques to elucidate tectonic activity and its influence on drainage patterns in the Nandakini Watershed,utilizing morphometric parameters derived from SRTM DEM data.Morphometric indices are employed to assess the tectonic movement within drainage basins,capturing both areal and linear factors such as drainage density,texture,circulatory and bifurcation ratios,and stream length ratios.The linear and areal morphometric indices are categorized into three classes representing varying degrees of active tectonic activity.These classifications are then utilized to compute the relative active tectonic index(IRAT).In addition,geomorphic parameters include hypsometric integral,stream length-gradient index,normalized steepness index,chi gradient index,and swath profiles.The majority of the studied region is in an extremely high to moderately active tectonic zone.Large-scale faults and thrusts within the basins are closely correlated with these zones that have been identified.The integrated methodology of GIS-based morphometric analysis and geomorphic study enables the identification of deformed landforms associated with ongoing tectonic activity.Furthermore,these results offer valuable insights for informing watershed management strategies and promoting sustainable land use planning initiatives.
文摘Soil erosion in the Hare watershed led to significant land degradation,water pollution,and reduced agricultural productivity.Despite its effects,very few researchers have used combined morphometric and RUSLE model techniques to quantify soil erosion and thereby prioritize impacted areas.This work used an automated GIS-based tool(SWPT)to prioritize crucial areas based on topohydrological and morphometric factors and predict soil loss in sub-watersheds using the RUSLE model.Land use/cover data were obtained from Landsat imagery,while slope and morphometric information were extracted from digital elevation data with a resolution of 12.5 m.Soil erodibility was determined using Ethiopian soil maps,and rainfall erosivity was computed using meteorological data.An average annual soil loss of 49 t ha-1 yr-1 was observed in the Hare watershed.Sub-watershed 11 was found to be the most affected,with an average annual soil loss of 85.12 t ha-1 yr-1and a compound parameter value(CPV)of 0.059.Subwatershed 17 has the least amount of soil loss,with 3.67t ha-1 yr-1 and a CPV of 1.32.The study emphasizes the usefulness of integrating RUSLE and morphometric analysis for soil and water conservation planning,suggesting a variety of modeling tools in data-sparse locations to quantify and prioritize erosion-prone areas.
基金supported by National Natural Science Foundation of China(No.62006092)University Synergy Innovation Program of Anhui Province(No.GXXT-2023-108)Excellent Youth Project of Natural Science Research in Anhui Province(No.2023AH030081).
文摘Accurate measurement of bean particle size is essential for automated grading and quality control in agricultural processing.However,existing image segmentation methods often suffer from low efficiency,over-segmentation,and high computational cost.We proposed a distancegradient dual constrained watershed algorithm for precise segmentation and measurement of bean particles.The method integrated distance transform-based seed extraction with gradient-constrained flooding,effectively suppressing noise-induced region fragmentation and improving the separation of adherent particles.An experimental platform was constructed using an industrial camera and an image-processing pipeline to evaluate performance.Compared with the conventional watershed algorithm,the proposed method improves segmentation accuracy by 7.2%and reduces the mean particle size error by 27.8%(0.13 mm,representing a relative error of 2.4%).Validation on three soybean varieties confirmed the robustness and generalizability of the approach.The results indicated that the proposed algorithm provided an efficient and accurate technique for agricultural particle size analysis,offering potential for integration into practical low-cost inspection systems.
基金supported by Gansu Provincial Youth Science and Technology Fund Program(No.21JR7RA701)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0605).
文摘Under the current global climate change background,the response of soil heavy metals in the Qinghai Tibet Plateau basin to the intensification of climate change is still unclear,leading to the intensification of heavy metal migration in the watershed.We selected cadmium(Cd)in soils of the Taohe River Basin on the Tibetan Plateau as the study object,and established a heavy metal migration simulation model based on the Soil and Water Assessment Tool(SWAT)to estimate the impact of climate change on Cd migration in the basin.The results indicated that the drought indexes and precipitation were the main determinants of the changes in Cd migration in the basin.The multi–scale drought indexes indicated that the optimal time scale for evaluating the effect of drought on Cd migration in the watershed was 3 months.Higher migration rates were apparent in summer and autumn(wet season)than in winter and spring(dry season).Spring precipitation was significantly and positively correlated with the migration of elemental Cd,and the Standardized Precipitation Index(SPI)3 drought index was significantly and positively correlated with Cd migration in summer,autumn,and winter.For every 5%increase in precipitation,Cd migration rates increased by 3.55%,0.46%,0.15%,and 0.12%in spring,summer,autumn,and winter,respectively.For every 5%decrease in precipitation,Cd migration rates decreased by 0.11%,0.12%,0.14%,and 0.13%in spring,summer,autumn,and winter,respectively.The risk of Cd transport in soil continues to increase under future climate change scenarios.
基金financially supported by China Geological Survey Project(No.DD20220954)Open Funding Project of the Key Laboratory of Groundwater Sciences and Engineering,Ministry of Natural Resources(No.SK202301-4)+2 种基金Science and Technology Innovation Foundation of Comprehensive Survey&Command Center for Natural Resources(No.KC20240003)Yanzhao Shanshui Science and Innovation Fund of Langfang Integrated Natural Resources Survey Center,China Geological Survey(No.YZSSJJ202401-001)Open Foundation of the Key Laboratory of Coupling Process and Effect of Natural Resources Elements(No.2022KFKTC009).
文摘Water scarcity and environment deterioration have become main constraints to sustainable economic and social development.Scientifically assessing Water Resources Carrying Capacity(WRCC)is essential for the optimal allocation of regional water resources.The hilly area at the northern foot of Yanshan Mountains is a key water conservation zone and an important water source for Beijing,Tianjin and Hebei.Grasping the current status and temporal trends of water quality and WRCC in representative small watersheds within this region is crucial for supporting rational water resources allocation and environment protection efforts.This study focuses on Pingquan City,a typical watershed in northern Hebei Province.Firstly,evaluation index systems for surface water quality,groundwater quality and WRCC were estab-lished based on the Pressure-State-Response(PSR)framework.Then,comprehensive evaluations of water quality and WRCC at the sub-watershed scale were conducted using the Varying Fuzzy Pattern Recogni-tion(VFPR)model.Finally,the rationality of the evaluation results was verified,and future scenarios were projected.Results showed that:(1)The average comprehensive evaluation scores for surface water and groundwater quality in the sub-watersheds were 1.44 and 1.46,respectively,indicating that both met the national Class II water quality standard and reflected a high-quality water environment.(2)From 2010 to 2020,the region's WRCC steadily improved,with scores rising from 2.99 to 2.83 and an average of 2.90,suggesting effective water resources management in Pingquan City.(3)According to scenario-based predic-tion,WRCC may slightly decline between 2025 and 2030,reaching 2.92 and 2.94,respectively,relative to 2020 levels.Therefore,future efforts should focus on strengthening scientific management and promoting the efficient use of water resources.Proactive measures are necessary to mitigate emerging contradiction and ensure the long-term stability and sustainability of the water resources system in the region.The evalua-tion system and spatiotemporal evolution patterns proposed in this study can provide a scientific basis for refined water resource management and ecological conservation in similar hilly areas.
文摘The Jiangxi province was divided into seven parts according to the concept of watershed,namely Poyang lake area,Fuhe,Xinjiang,Ganjiang,Xiuhe,Raohe and other river watersheds.The ecological supply and demands status of the former six parts from 2000 to 2006 was computed based on the ecological footprint model and a spatiotemporal comparative analysis to them was conducted.The result showed that:①all the studied areas had an increasing ecological deficit and they were in the status of unsustainable development;② the arable land footprint's demand were about 80% of their total footprint's demand respectively,so it was of great significance to protect and exploit arable land resources scientifically;③ the ecological deficit of grassland and forest resources can not be ignored.
文摘A thorough analysis on its natural environment as well as social economic status of the hilly-gullied loess region is presented. A small watershed, the dominant landscape unit of the region, has been singled out for further and specific study on landscape pattern and function, its social and economic distinctions. The authors proposed several principles based on its eco-economic background study, which includes water balance and efficient use principle, co-development of grass and agro-forestry principle, location optimization principle. Integrated with detailed analysis of a small watershed, an eco-productive paradigm for the loess land's development based on a small watershed scale was worked out. It consists of circle pattern with villages at core for high efficient agriculture production, hierarchical pattern along the slope for eco-economic development, point-axis pattern for commodity production and circulation in small watersheds and core-margin pattern for exchanges among watersheds.
文摘The changes of grassland landscape pattern in Qinghai Lake watershed from 1977 to 2000 were studied by adopting 3S technologies and landscape pattern analysis.The results showed that the amount of grassland landscape patch reduced,landscape fragmentation and resolution decreased,but average patch area and fractal dimension increased;through analyzing the landscape change of counties in Qinghai Lake watershed,the grassland landscape structure of Tianjun,Gangcha and Haiyan counties showed a similar change trend;but in Gonghe County grassland patch amount,landscape fragmentation and resolution increased,average patch area decreased,that is,the grassland landscape structure in this county showed a different trend.
文摘Xiayun Township watershed in the upper reaches of Hongfeng Lake is selected to study the relationship between stream grade and water quality.Turbidity and ammonium nitrogen concentration are obviously related to the stream grade,generally speaking,are positively correlated,and the water quality is degrading from the upper reaches to the lower reaches.In the future,the influence of different land use types on the water quality should be fully analyzed on the basis of enhancing the water quality monitoring to provide supports for effectively controlling non-point source pollutions and treating the water environment of Hongfeng Lake.
