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1.
Environ Sci Ecotechnol ; 22: 100450, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39161573

RESUMEN

Rainfall data with high spatial and temporal resolutions are essential for urban hydrological modeling. Ubiquitous surveillance cameras can continuously record rainfall events through video and audio, so they have been recognized as potential rain gauges to supplement professional rainfall observation networks. Since video-based rainfall estimation methods can be affected by variable backgrounds and lighting conditions, audio-based approaches could be a supplement without suffering from these conditions. However, most audio-based approaches focus on rainfall-level classification rather than rainfall intensity estimation. Here, we introduce a dataset named Surveillance Audio Rainfall Intensity Dataset (SARID) and a deep learning model for estimating rainfall intensity. First, we created the dataset through audio of six real-world rainfall events. This dataset's audio recordings are segmented into 12,066 pieces and annotated with rainfall intensity and environmental information, such as underlying surfaces, temperature, humidity, and wind. Then, we developed a deep learning-based baseline using Mel-Frequency Cepstral Coefficients (MFCC) and Transformer architecture to estimate rainfall intensity from surveillance audio. Validated from ground truth data, our baseline achieves a root mean absolute error of 0.88 mm h-1 and a coefficient of correlation of 0.765. Our findings demonstrate the potential of surveillance audio-based models as practical and effective tools for rainfall observation systems, initiating a new chapter in rainfall intensity estimation. It offers a novel data source for high-resolution hydrological sensing and contributes to the broader landscape of urban sensing, emergency response, and resilience.

2.
Sci Total Environ ; 948: 174731, 2024 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-39002587

RESUMEN

Canopy interception significantly affects hydrological processes such as infiltration, runoff and evapotranspiration. Research on grass canopy interception remains limited, and the experimental methods employed differ substantially. To thoroughly investigate the canopy interception characteristics of grass and clarify the methodological differences, five commonly utilized slope protection grass species in temperate regions were cultivated in a laboratory setting, and their canopy interception characteristics were experimentally investigated using the water-balance method (WBM), the water-wiping method (WWM) and the water-immersion method (WIM), respectively. The results showed that the WBM is more accurate for measuring canopy interception in grass, whereas both the WWM and the WIM underestimate grass canopy interception capacity. The canopy interception capacity measured by the WBM was 1.61-2.09 times higher than that of the WWM and 1.93-3.47 times higher than that of the WIM. Grey correlation analysis of the eight evaluated factors indicated that leaf area is the most influential factor affecting canopy interception in grass, followed by rainfall amount, dry mass, rainfall intensity, canopy projection area, leaf contact angle, fresh weight, and average height. There is a negative power function relationship between the interception ratio and the rainfall amount. With increasing rainfall intensity, the canopy interception capacity initially increases and then decreases, peaking at rainfall intensities of 15 to 20 mm/h. Leaf contact angle is a key quantifiable parameter that explains the differences in canopy interception among different grass species, and the canopy interception per unit leaf area decreases as the leaf contact angle increases. This study demonstrates that the WBM provides the most accurate measurements of grass canopy interception compared to the WWM and WIM, and highlights the leaf contact angle as a key factor in explaining interspecies differences. These findings could enhance the understanding of grass canopy interception and guide the selection of experimental methods.


Asunto(s)
Poaceae , Poaceae/fisiología , Hojas de la Planta/fisiología , Conservación de los Recursos Naturales/métodos , Lluvia , Hidrología , Monitoreo del Ambiente/métodos
3.
Sci Total Environ ; 892: 164427, 2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37245809

RESUMEN

The capture of colloidal fine suspended particles by vegetation plays an important role in water quality of the shallow aquatic system under rainfall. Quantifying impact of rainfall intensity and vegetation condition on this process remains poorly characterized. In this study, the colloidal particle capture rates under three rainfall intensities, four vegetation densities and with submerged or emergent vegetation were investigated in different travel distance in a laboratory flume. Considering vegetation as porous media, non-Darcy's law with rainfall as a source term, was coupled with colloid first-order deposition model, to simulate the particle concentration changes with time, determining the particle deposition rate coefficient (kd), representing capture rate. We found that the kd increased linearly with rainfall intensity; but increased and then decreased with vegetation density, suggesting the existence of optimum vegetation density. The kd of submerged vegetation is slightly higher than emergent vegetation. The single collector efficiency (η) showed the same trend as kd, suggesting colloid filtration theory well explained the impact of rainfall intensity and vegetation condition. Flow hydrodynamic enhanced the kd trend, e.g., the theoretical strongest flow eddy structure represented in the optimum vegetation density. This study is helpful for the design of wetland under rainfall, to remove colloidal suspended particles and the hazardous material, for the protection of the downstream water quality.


Asunto(s)
Coloides , Porosidad
4.
Plants (Basel) ; 12(3)2023 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-36771513

RESUMEN

Environmental loss is primarily caused by soil, water, and nutrient loss, and runoff is associated with nutrient transport and sediment loss. Most existing studies have focused on one influencing factor, namely slope gradient or rainfall intensity, for slope erosion and nutrient loss, but the joint effects of the two factors have rarely been researched. In this context, the impact of slope gradients (0°, 5°, 10°, and 15°) and rainfall intensities (30, 40, 50, 60, 70, and 80 mm/h) on soil erosion and nutrient loss on the sloping fields of Miyun Reservoir were explored using the indoor artificial rainfall simulation testing system. Based on the results of the study, the variation of runoff coefficient with slope gradient was not noticeable for rainfall intensities <40 mm/h; however, for rainfall intensities >40 mm/h, the increased range of runoff coefficient doubled, and the increase was the fastest under 0° among the four slope gradients. The slope surface runoff depth and runoff rate showed positive correlations with the rainfall intensity (r = 0.875, p < 0.01) and a negative correlation with the slope gradient. In addition, the cumulative sediment yield was positively related to the slope gradient and rainfall intensity (r > 0.464, p < 0.05). Moreover, the slope surface runoff-associated and sediment-associated loss rates of total nitrogen (TN) rose as the rainfall intensity or slope gradient increased, and significant linear positive correlations were found between the runoff-associated TN loss rate (NLr) and the runoff intensity and between the sediment-associated NLr and the erosion intensity. In addition, there were positive linear correlations between slope runoff-associated or sediment-associated TN loss volumes and rainfall intensity, surface runoff, and sediment loss volumes, which were highly remarkable. The slope gradient had a significant positive correlation with the slope surface runoff-associated TN loss at 0.05 (r = 0.452) and a significant positive correlation with the sediment-associated TN loss at the level of 0.01 (r = 0.591). The rainfall intensity exhibited extremely positive correlations with the slope surface runoff-associated and sediment-associated TN loss at 0.01 (r = 0.717 and 0.629) Slope gradients have less effect on nitrogen loss on sloped fields than rainfall intensity, mainly because rainfall intensity affects runoff depth. Based on the findings of this study, Miyun Reservoir may be able to improve nitrogen loss prevention and control.

5.
Materials (Basel) ; 16(2)2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36676570

RESUMEN

Basalt platforms are widely distributed in many areas of China, where landslides occur frequently. It is well recognized that landslide hazards seriously threaten engineering constructions and property safety. It is, therefore, of great significance to understand deformation and failure behaviors and their mechanisms in basalt slopes to reduce the loss caused by landslides. In this work, the Pengshan Landslide in Zhejiang Province is taken as a prototype and slope model tests are carried out. During the tests, real-time monitoring of pore pressure, earth pressure and slope deformation is conducted. Based on the experimental data, the influence of rainfall intensity and the thickness of a weak interlayer on the slope stability are obtained. It is demonstrated that the rainfall and weak interlayer are the most important factors causing the slope instability of a basalt platform. Furthermore, damage from a basalt platform slope usually starts from local failure, and the slope foot is the most likely sliding part. Moreover, when the rainfall intensity is doubled, the initial deformation time of the slope is reduced by about half and the final failure time is advanced by one-third. In addition, when the thickness of the weak interlayer is doubled, the initial deformation time of slope is shortened by about half and the final failure time is advanced by one-quarter.

6.
Environ Monit Assess ; 195(2): 280, 2023 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-36622448

RESUMEN

Floods are among the most serious and devastating phenomena of natural disasters. Cities adjacent to flood-prone areas in the last decades have played a major role in increasing the potential adverse effects of flood damage. This research study aims to evaluate and mitigate the risks of flood events in the El Bayadh region, which suffers from poor infrastructure and drained networks. To achieve this, it is necessary to evaluate rainfall intensities and their limits for durations from 0.167 to 24 h with return periods from 2 to 1000 years. Eight different frequency analysis distributions were fit to the historical rainfall data series over 43 years (1970-2012) using hypothesis-based goodness tests and information-based criteria. The most appropriate distributions were used to develop the rainfall intensity-duration-frequency (IDF) and flood risk-duration-frequency (RDF) curves for the study area. The results show that high-intensity rainfall values last for short durations, while high flood risk values last for intermediate durations. The results of the flood RDF curves can provide useful information for policy makers to make the right decisions regarding the effectiveness of the region's protection structures against future flood risks.


Asunto(s)
Inundaciones , Evaluación y Mitigación de Riesgos , Argelia , Ciudades , Monitoreo del Ambiente/métodos , Inundaciones/prevención & control , Lluvia , Desastres
7.
Environ Sci Pollut Res Int ; 30(14): 41253-41271, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36630042

RESUMEN

Detention pond is a key storm water management measure employed both to attenuate surface runoff and to regulate depression storage, yet the effects of aquaculture ponds and reservoirs on runoff coefficient are not well quantified in a subtropical humid monsoon climate zone, China. Here, a set of six subcatchments ranging in size from 0.7 hm2 to 10,000 hm2 were evaluated over the 2011-2015 period. (i) The annual average runoff coefficient differed with different subcatchments due to the spatial heterogeneity of landscape patterns, while the event-based runoff coefficient under the same catchment showed a decreasing trend with increasing rainfall intensity. (ii) The annual average and event-based runoff coefficients initially increased and then decreased with an increase in the area ratio of aquaculture ponds and reservoirs. The critical area ratio of aquaculture ponds and reservoirs for the maximum runoff coefficient in annual, light, and moderate rainfall intensity was about 4%; but this value would be transferred forward to the position of < 4% under the intensity of heavy rain, rainstorms, and heavy rainstorms. (iii) All runoff coefficients decreased with increasing forestland but increased with increasing paddy fields, and the decreasing rate was greater than the increasing rate. The trends of runoff coefficient for the annual and event-based rainfall are opposite between river development coefficient and watershed shape coefficient. The results provide underlying insights for decision-makers in aquaculture land-use planning and the sustainable utilization of water resources in the upstream and downstream systems of a catchment.


Asunto(s)
Estanques , Lluvia , Movimientos del Agua , Acuicultura , China , Monitoreo del Ambiente
8.
J Environ Manage ; 330: 117176, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36608605

RESUMEN

To analyse the moisture migration characteristics of permeable asphalt pavement (PAP) in engineering applications, a PAP sample with a length and width of 163 m and 12 m, respectively, was designed and paved. The pavement comprised PAC-13, PAC-20, ATPB-25, graded grade, and sandy soil subgrade from the top to the bottom. Moisture sensors were set at 4 cm, 10 cm, 28 cm, 46 cm, 61 cm, 76 cm, 101 cm, 126 cm, 176 cm, and 226 cm below the pavement surface to ascertain the volumetric water content during and after rainfall. This data were used to analyse the changes in the infiltration depth, infiltration rate, water level height, and water emptying time of the PAP under different rainfall conditions. The results show that the prediction model for the infiltration depth can be established using the water adhesion rate and rainfall. According to the moisture changes of the pavement layer after rainfall, the water migration process of the PAP can be divided into the drying stage, wetting stage, emptying stage, and recovery drying stage. The relationship between the average rainfall intensity and the average infiltration rate is a linear function. The water emptying time at the depth of 0-10 cm is less than 20 h, and the emptying time at a depth below 10 cm is less than 6 d.


Asunto(s)
Lluvia , Movimientos del Agua , Calidad del Agua , Agua
9.
Sci Total Environ ; 863: 160759, 2023 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-36509276

RESUMEN

River turbidity is an important factor in evaluating environmental water quality, and turbidity dynamics can reflect water sediment changes. During rainfall periods, specifically in mountainous areas, river turbidity varies dramatically, and knowledge of spatiotemporal turbidity variations in association with rainfall features and farming activities is valuable for soil erosion prevention and catchment management. However, due to the difficulties in collecting reliable field turbidity data during rainstorms at a fine temporal scale, our understanding of the features of turbidity variations in mountainous rivers is still vague. This study conducted field measurements of hydrological and environmental variables in a mountainous river, the Lai Chi Wo river, in Hong Kong, China. The study results revealed that variations of turbidity graphs during rainstorms closely match variations of streamflow hydrographs, and the occurrence of the turbidity peaks and water level peaks are almost at the same time. Moreover, the study disclosed that the increasing rates of the turbidity values are closely related to the rainfall intensity at temporal scales of 15 and 20 min, and the impact of farming activities on river turbidity changes is largely dependent on rainfall intensity. In the study area, when the rainfall intensity is larger than 35 mm/hr at a time interval of 15 min, the surface runoff over the farmland would result in higher river water turbidity downstream than that upstream. The study results would enrich our understanding of river water turbidity dynamics at minute scales and be valuable for further exploration of the river water environment in association with turbidity.

10.
Environ Monit Assess ; 195(1): 170, 2022 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-36459269

RESUMEN

Climate change impacts are one of the global challenges that change the intensity and frequency of rainfall. The Dodola town has previously experienced rainfall-induced flooding effects, and future floods may be more frequent and severe due to possible variations in rainfall intensity due to climate change. In this study, the rainfall intensity-duration-frequency (IDF) curves are updated for the design of urban stormwater drainage infrastructures under climate change to reduce flooding risks. To assess the variations in the rainfall intensity, the future IDF curves for the periods (2020-2100) and two GCMs (CanESM2 and HadGEM2-ES) were derived and compared to the current IDF curves. It was found that rainfall intensities for future climate conditions will differ from the current period for all durations and return periods. The comparison results show that the relative change between future rainfall intensities and historic rainfall ranges from 1.5 to 30.6%, 2.48 to 42.6%, and 3.7 to 23.24% for 2020-2040, 2041-2070, and 2071-2100, respectively. The IDF relationships revealed that as a result of climate change, urban flooding will increase in the future. This study will help to better understand the impacts of climate change on rainfall IDF relationships, as well as have implications for the design of current and future stormwater management systems in Dodola, Ethiopia.


Asunto(s)
Cambio Climático , Monitoreo del Ambiente , Etiopía , Inundaciones , Lluvia
11.
Ecotoxicol Environ Saf ; 247: 114238, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-36323152

RESUMEN

Precipitation is considered the most effective way to remove particulate matter from the leaves of plants. Changes in rainfall characteristics can affect the scavenging processes of particulate matter from leaves. In order to better understand the dynamics of PM scavenging during rainfall, especially the water-soluble ions components, leaves from the 11 plant species (trees, shrubs, terrestrial herbs, wetland plants) from the Olympic park were sampled and used in indoor experiments. During the experiments, the rainfall intensity was set at 30 mm/h, 45 mm/h, and 60 mm/h, and the duration was divided into 0-20 min, 20-40 min, and 40-60 min. The sampled plant leaves were set in the experiments at 1 m and 3 m height from the ground. Concentrations and compositions of nine water-soluble ions of rainfall samples were analyzed in this experiment. The results revealed that SO42-, Ca2+, and Na+ were the most abundant ionic species removed from the leaves, and NO3- ranked fourth, followed by Cl-, Mg2+ K+, NH4+, and F-. The ions concentration of rainfall samples decreased when the rain intensity increased from 30 to 45 mm/h and when the rain intensity increased to 60 mm/h. The efficiency of scavenging during different rainfall durations depends on the ionic species. Na+, Mg2+, Ca2+, and SO42- concentrations increased with the increase in rainfall duration, whereas those of NH4+, K+, and Cl- decreased. The effect of leaf height on ions concentration of rainfall samples was also different among the ionic species: Na+, Mg2+, Ca2+, NO3-, and F- concentrations were significantly higher at 1 m compared with 3 m. The principal component analysis of ions in rainfall samples revealed two main sources of particulate matter in our study. One is from vehicle exhaust and industrial and agricultural pollution. The other is agricultural combustion and ground dust sources. The results of the above study can provide a basis and theoretical support for the establishment of urban cleaning systems and the prevention of air pollution.


Asunto(s)
Hojas de la Planta , Agua , Iones , Árboles , Material Particulado
12.
Sci Total Environ ; 849: 157691, 2022 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-35907540

RESUMEN

Road waterlogging has become a significant issue in developed cities due to the rapid urbanization in China. It is necessary to accurately identify the risk of waterlogging in urban roads and propose appropriate mitigation measures. This study considered urban waterlogging as a landscape ecological process. The road waterlogging risk was simulated and estimated using the Minimum Cumulative Resistance model under natural drainage conditions. The results indicate that: 1) The Minimum Cumulative Resistance model effectively assesses the waterlogging risk for each road segment. The roads in and around the central city have relatively higher waterlogging risks. The overall length of high-risk roads is 918.7 km, accounting for 31.3 % of the total. 2) There are 448 potential runoff paths and 448 inflow sites. The city's center and its north and south sides are the primary locations of the high-risk runoff paths and the inflow sites. 3) Road waterlogging is significantly more affected by the land-use types of High density residential and Industrial under rainfall intensities of a-year, 2-year, 3-year, and 5-year return periods. And the effects of various land-use types on waterlogging vary with the rainfall intensity. Using landscape ecology theory to analyze the risk of road waterlogging is a novel method to address urban waterlogging issues. This approach provides a more accurate approach to identifying the urban waterlogging risks and can be applied to developed cities suffering from waterlogging to help decision-makers devise the most effective mitigation measures.


Asunto(s)
Urbanización , China , Ciudades
13.
Environ Geochem Health ; 44(10): 3395-3407, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34608596

RESUMEN

Urban development and climate change have led to severe waterlogging in cities. To study the degree of mitigation of urban waterlogging using the design of sponge city roads, this study employed No. 9 Road in the Sino-German Eco-park. By establishing the scaled physical model, the pavement structure of the sponge city road was optimized. Furthermore, water migration (seepage, impoundment, and drainage) rule was obtained under different rainfall intensities using the optimal pavement scheme. The following conclusions were drawn from the studies. Good permeability of the sidewalk surface structure is conducive for rainwater collection. The sponge urban road rainwater collection and utilization system could absorb up to 88% of rainwater under the rainfall intensity of 173 mm (extra heavy rain), and could absorb up to 100% of rainwater under heavy rain conditions. The seepage volume increased exponentially with the rise in rainfall intensity, and the amount of water storage increased linearly with the rainfall intensity. These results can provide guidance for safety early warning of urban waterlogging on No. 9 Road in the Sino-German Eco-park and deeper insights in the design of sponge city roads.


Asunto(s)
Lluvia , Movimientos del Agua , China , Ciudades , Agua
14.
Artículo en Inglés | MEDLINE | ID: mdl-34886296

RESUMEN

Water quality degradation is one of the major problems with artificial lakes in estuaries. Long-term spatiotemporal patterns of water quality in a South Korean estuarine reservoir were analyzed using seasonal datasets from 2002 to 2020, and some functional changes in relations of trophic state variables due to the construction of serial weirs in the upper river were also investigated. A total of 19 water quality parameters were used for the study, including indicators of organic matter, nutrients, suspended solids, water clarity, and fecal pollution. In addition, chlorophyll-a (CHL-a) was used to assess algal biomass. An empirical regression model, trophic state index deviation (TSID), and principal component analysis (PCA) were applied. Longitudinal fluctuations in nutrients, organic matter, sestonic CHL-a, and suspended solids were found along the axis of the riverine (Rz), transition (Tz), and lacustrine zones (Lz). The degradation of water quality was seasonally caused by resuspension of sediments, monsoon input due to rainfall inflow, and intensity of Asian monsoon, and was also related to intensive anthropic activities within the catchment. The empirical model and PCA showed that light availability was directly controlled by non-algal turbidity, which was a more important regulator of CHL-a than total nitrogen (TN) and total phosphorus (TP). The TSID supported our hypothesis on the non-algal turbidity. We also found that the construction of serial upper weirs influenced nutrient regime, TSS, CHL-a level, and trophic state in the estuarine reservoir, resulting in lower TP and TN but high CHL-a and high TN/TP ratios. The proportions of both dissolved color clay particles and blue-green algae in the TSID additionally increased. Overall, the long-term patterns of nutrients, suspended solids, and algal biomass changed due to seasonal runoff, turnover time, and reservoir zones along with anthropic impacts of the upper weir constructions, resulting in changes in trophic state variables and their mutual relations in the estuarine reservoir.


Asunto(s)
Eutrofización , Calidad del Agua , China , Clorofila/análisis , Monitoreo del Ambiente , Lagos , Nitrógeno/análisis , Fósforo/análisis
15.
Sensors (Basel) ; 21(19)2021 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-34640731

RESUMEN

The features of the atmospheric γ-background reaction to liquid atmospheric precipitation in the form of bursts is investigated, and various forms of them are analyzed. A method is described for interpreting forms of the measured γ-background response with the determination of the beginning and ending time of precipitation, the distinctive features of changes in the intensity of precipitation and the number of single (separate) events that form one burst. It is revealed that a change in the intensity of precipitation in one event leads to a change in the γ-radiation dose rate increase speed (time derivative). A method of estimating the average value of the intensity and amount of precipitation for one event, reconstructing the intensity spectrum from experimental data on the dynamics of the measured dose rate of γ-radiation, is developed. The method takes into account the radioactive decay of radon daughter products in the atmosphere and on the soil surface during precipitation, as well as the purification of the atmosphere from radionuclides. Recommendations are given for using the developed method to correct for changes (daily variations) in radon flux density from the ground surface, which lead to variations in radon in the atmosphere. Experimental verification of the method shows good agreement between the values of the intensity of liquid atmospheric precipitation, calculated and measured with the help of shuttle and optical rain precipitation gauges.


Asunto(s)
Contaminantes Radiactivos del Aire , Radón , Contaminantes Radiactivos del Aire/análisis , Atmósfera , Rayos gamma , Lluvia
16.
J Hazard Mater ; 417: 126159, 2021 09 05.
Artículo en Inglés | MEDLINE | ID: mdl-34229412

RESUMEN

Eroded particles from the source zone could transport a high concentration of perfluoroalkyl acids (PFAAs) to sediments and water bodies. Yet, the contribution of suspended particles has not been systematically reviewed. Analyzing reported studies, we quantitatively demonstrate that suspended particles in surface water can contain significantly higher concentrations of PFAAs than the sediment below, indicating the source of suspended particles are not the sediment but particles eroded and carried from the source zone upstream. The affinity of PFAAs to particles depends on the particle composition, including organic carbon fraction and iron or aluminum oxide content. In soils, most PFAAs are retained within the top 5 m below the ground surface. The distribution of PFAAs in the subsurface varies based on site properties and local weather conditions. The depth corresponding to the maximum concentration of PFAA in soil decreases with an increase in soil organic carbon or rainfall amount received in the catchment areas. We attribute a greater accumulation of PFAAs near the upper layer of the subsurface to an increase in the accumulation of particles eroded from source zones upstream receiving heavy rainfall. Precursor transformation in the aerobic zone is significantly higher than in the anaerobic zone, thereby making the aerobic subsurface zone serve as a long-term source of groundwater pollution. Collectively, these results suggest that suspended particles, often an overlooked vector for PFAAs, can be a dominant pathway for the transport of PFAAs in environments.


Asunto(s)
Fluorocarburos , Agua Subterránea , Contaminantes Químicos del Agua , Carbono , Monitoreo del Ambiente , Fluorocarburos/análisis , Suelo , Contaminantes Químicos del Agua/análisis
17.
Environ Sci Pollut Res Int ; 28(28): 37204-37216, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33712958

RESUMEN

Soil total carbon (TC), phosphorus (P), and nitrogen (N) exports from the weathered granite slopes are greatly influenced by the complex hydrological processes and terrain factors. In this study, the coupling loss characteristics of N-P-C via runoff and sediment were studied with two soil tanks under simulated rainfalls. Three soils respectively derived from the tillage layer (T-soil), laterite layer (L-soil), and sand layer (S-soil) were employed to determine the interactions of hydrology and topography on N-P-C exports under three rainfall intensities (1.5, 2.0, and 2.5 mm/min). The erosion degree of different soils displayed an order of S-soil > L-soil > T-soil. The results showed that surface flow was the main runoff form for L- and T-soil, while underground flow was predominant for S-soil. There was a linear correlation between sediment and surface flow (R2 > 0.78). Surface flow was the dominant pathway of P loss via runoff with underground flow being an important supplementation, and the main P loss pattern switched between dissolved phosphorus (DP) and particle phosphorus (PP) during the experiment. However, P lost via eroded sediment accounted for more than 94% of the TP loss amount. N presented an opposite trend to P and was mainly lost via underground flow. The main N loss form in surface and underground flow was NO3--N. Underground flow was the predominant total nitrogen (TN) loss pathway for S- and L-soil, followed by sediment and surface flow. For T-soil, TN lost via runoff was much greater than that carried by eroded sediment. TC for S-soil was mainly lost via underground flow while that for L- and T-soil was mostly lost via surface flow. Both N-P loss loads in surface flow and P loss load in underground flow were positively correlated with TC loss load (p < 0.05), indicating that the presence of organic matter brings about more nutrient losses. These results expand our understanding of the combined effects of rainfall intensity and erosion degree on runoff and sediment yields as well as N-P-C losses from the bare weathered granite slopes of SE China.


Asunto(s)
Lluvia , Movimientos del Agua , China , Fósforo/análisis , Suelo
18.
Environ Sci Pollut Res Int ; 28(12): 15114-15122, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33226556

RESUMEN

To investigate the effectiveness of different permeable bricks on the pollutants from urban rainfall runoff, three common used bricks (ceramic brick, cement brick, and steel slag brick) were selected and applied to study their decontamination performance. The influencing factors such as rainfall intensity and contaminant concentrations were investigated. Then the ultrapure water was used to wash the permeable brick to research the pollution status and cleaning characteristics by monitoring the water quality of the rinsing water. Suspended solids (SS), chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN), total phosphorus (TP), and heavy metals (Cu, Zn, Pb, and Cd) in the influent and effluent were measured. The results showed the following: (I) The upper layer of the brick may play a more critical role in purification process; the uniform and dense pore distribution of ceramic permeable brick was instrumental in the retention of particulates. (II) Contaminant concentration and rainfall intensity had a great influence on pollutants with lower removal rate and had little effect on pollutants with higher removal rate. (III) Non-sintered bricks containing a certain amount of cement increased the pH after filtration. (IV) The removal performance of permeable brick for dissolved pollutants such as COD, NH4-N, and TN was inferior to that for SS, TP, and heavy metals since the discrepancy in removal mechanism of pollutants. The study could offer a new perspective for the decontamination research of pervious bricks.


Asunto(s)
Movimientos del Agua , Contaminantes Químicos del Agua , Descontaminación , Monitoreo del Ambiente , Nitrógeno/análisis , Fósforo/análisis , Lluvia , Contaminantes Químicos del Agua/análisis
19.
Sci Total Environ ; 727: 138468, 2020 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-32334212

RESUMEN

Smoldering wildfire in peatlands contributes significantly to global carbon emissions and regional haze events. Smoldering fire in peatlands is one of the largest and most persistent fire phenomena on Earth. Here we assess the underlying mechanism of rain in suppressing the smoldering peat fire in the shallow soil layer up to 15 cm deep through laboratory experiments. We show that the minimum rainfall intensity to extinguish the peat fire is roughly 4 mm/h, so that the persistent light rain cannot suppress such smoldering wildfire. The required rain duration, ∆t (min), for extinguishing smoldering peat fire decreases with the rainfall intensities, I (mm/h), as log10∆t = - 1.15log10I + 3.3, and is much longer than that for extinguishing flaming wildfire. We also identify that the required rainfall depth for extinguishing peat fire gradually decreases with the rainfall intensity and approaches a minimum value of 13 mm under violent rain. As rainfall intensity increases, the carbon emission flux from peat fire decreases. Therefore, we conclude that the short-term violent rain is most effective for suppressing the persistent smoldering peat fire. This research helps evaluate the impact of weather on the development of peat fire and improve the prediction of carbon emissions from peat fire with the use of regional weather models.

20.
Sci Total Environ ; 713: 136705, 2020 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-32019040

RESUMEN

Research on sustainable use of water resources is needed to ensure food security, limit erosion, and prevent land degradation. Owing to the importance of water conservation to ecosystems, further research on the water conservation functions of different ecosystems is needed. Given the influence on water conservation functions, it is critical to identify environmental factors mediating slope runoff. In this study, the focal study area was the Yangjuangou catchment (36°42' N, 109°31' E) of the Loess Plateau in Shaanxi Province, China. Using a trait-based approach, a quantitative analysis was conducted to research effects of the functional structure parameters of plant communities on runoff of grass slopes for different periods of the year under differing rainfall intensity conditions. Results show that in mid-June, which represents the start of the growing season, effects of root traits on slope runoff decrease with increasing rainfall intensity. Slope runoff was found to be mainly affected by various plant functional traits in late July and aboveground parts of plants in early September. Given that few studies have focused on runoff processes using a trait-based approach at the community scale, this research can serve as a new reference for investigating the relationship between slope runoff and vegetation.


Asunto(s)
Pradera , China , Conservación de los Recursos Naturales , Monitoreo del Ambiente , Sedimentos Geológicos , Lluvia , Suelo , Movimientos del Agua
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