Modelling wildfire ash transport by concentrated flow

2021 ◽  
Author(s):  
Jonay Neris ◽  
Robert E. Brown ◽  
Peter R. Robichaud ◽  
William J. Elliot ◽  
Cristina Santin ◽  
...  
Keyword(s):  
Average Concentration ◽  
Inorganic Materials ◽  
Critical Parameters ◽  
Conifer Forest ◽  
High Concentration ◽  
Aquatic Life ◽  
Concentrated Flow ◽  
Runoff Rate ◽  
In Fire ◽  
Ash Transport

<p>Wildfire ash is a mixture of pyrogenic organic and inorganic materials with high concentration in nutrients and potential contaminants that is easily mobilized by runoff. Ash has been identified as a major threat to water quality since it can impact aquatic life and disrupt water treatment operations when is washed off into water bodies. The ability to modelling ash transport, however, is in its infancy.  One reason for this is that the relationship between runoff and ash transport for concentrated flow has not been described yet, limiting the capabilities of current runoff-erosion models to predict ash transport and delivery in fire-affected areas.</p><p>To fill this knowledge gap, we conducted a series of laboratory experiments on ash transport using concentrated flow on flumes. Ash collected from US conifer forest burned at high severity was applied at two different rates (corresponding to layers of 1 and 3 cm thickness) to an artificial substrate of gravel and sand attached to the bottom of the flumes that simulates soil roughness. Three different flow rates were consecutively applied to each flume in all possible combinations (6 flow rate combinations and 6 replicates per combination and ash thickness).</p><p>The results show that ash is easily transported by concentrated flow, confirming previous observations on ash mobility. The runoff rate required to start transporting the ash was close to 0 (0.005 L min<sup>-1 </sup>for both 1 and 3 cm ash layers) and the average concentration of ash in the runoff once this process started was considerably high (120 and 176 g L<sup>-1</sup> for 1 and 3 cm ash layers respectively), probably due to the low density and cohesion of this fire by-product. The results also show that ash depletion is a critical process when modelling ash transport and, thus, that ash transport by concentrated flow is better modelled using a variable sediment transport rate to account for ash decay with consecutive rainfall events. This is especially true for the 1 cm ash layer. The relationships between runoff and ash transport for concentrated flow obtained here for the evaluated ash type and loads are critical parameters to predict ash transport and will be used to refine ash transport capabilities of WEPPcloud-WATAR, a new tool aimed at predicting ash contamination risks after wildfires.</p>

Formation of water chemistry in the Modonkul river under the action of mine drainage effluent

2020 ◽  
pp. 56-66
Author(s):  
Z. I. Khazheeva ◽  
S. S. Sanzhanova
Keyword(s):  
Water Chemistry ◽  
Mine Drainage ◽  
High Concentration ◽  
Catchment Basin ◽  
Sulfate Anion ◽  
Concentrated Flow ◽  
Sodium Calcium ◽  
Calcium Cation ◽  
Calcium Magnesium ◽  
The Town

The Dzhida ore field in the Zakamensk district of Buryatia features high concentration of mineralization within a small area. The Dzhida deposit is composed of complex ore. The ore field contains commercial-value primary deposits: Pervomai stockwork of molybdenum, Kholtoson tungsten lode and Inkur stockwork of tungsten. The Modonkul river catchment basin lies inside the Dzhida ore field. A real threat to the town of Zakamensk is created by manmade sand-bulk (old) tailings and slurry dump. By now, the concentrated flow of natural and man-made sand enters the low terrace and floodplain of the Modonkul river in the form of a talus train. This study is focused on the influence of the mine drainage effluent and the Inkur tributary on the water chemistry in the Modonkul river. 80 water samples were taken from the surface layer 0-0.5 m thick at five stations. Physicochemical indices of water were measured at the water sampling points, and the water chemistry was analyzed in a laboratory. In the background conditions, cations and anions in the Modonkul water chemistry range in decreasing order as follows: Са2+ > Mg2+ > Na++К+ и HCO - > SO 2- > Cl-. In the zone of mixture of natural and mine process water, the chemistry changes: from hydrocarbonate to sulfate (anion), from calcium-magnesium to sodium-calcium (cation). Downstream the natural chemistry changes to the hydrocabonate-sulfate composition, with prevailing content of calcium in cations. Iron content of water lowers 3-4 times after influx of mine effluents, while the contents of Mn, Zn, Co and Cd grow and then decrease downstream.

scholarly journals Changes in Nitrogen-Fixing and Ammonia-Oxidizing Bacterial Communities in Soil of a Mixed Conifer Forest after Wildfire

2005 ◽  
Vol 71 (5) ◽  
pp. 2713-2722 ◽  
Author(s):  
Chris M. Yeager ◽  
Diana E. Northup ◽  
Christy C. Grow ◽  
Susan M. Barns ◽  
Cheryl R. Kuske
Keyword(s):  
Bacterial Communities ◽  
Fragment Length Polymorphism ◽  
Rflp Analysis ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrogen Fixing ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Mixed Conifer Forest ◽  
In Fire ◽  
Sequence Types

ABSTRACT This study was undertaken to examine the effects of forest fire on two important groups of N-cycling bacteria in soil, the nitrogen-fixing and ammonia-oxidizing bacteria. Sequence and terminal restriction fragment length polymorphism (T-RFLP) analysis of nifH and amoA PCR amplicons was performed on DNA samples from unburned, moderately burned, and severely burned soils of a mixed conifer forest. PCR results indicated that the soil biomass and proportion of nitrogen-fixing and ammonia-oxidizing species was less in soil from the fire-impacted sites than from the unburned sites. The number of dominant nifH sequence types was greater in fire-impacted soils, and nifH sequences that were most closely related to those from the spore-forming taxa Clostridium and Paenibacillus were more abundant in the burned soils. In T-RFLP patterns of the ammonia-oxidizing community, terminal restriction fragments (TRFs) representing amoA cluster 1, 2, or 4 Nitrosospira spp. were dominant (80 to 90%) in unburned soils, while TRFs representing amoA cluster 3A Nitrosospira spp. dominated (65 to 95%) in fire-impacted soils. The dominance of amoA cluster 3A Nitrosospira spp. sequence types was positively correlated with soil pH (5.6 to 7.5) and NH3-N levels (0.002 to 0.976 ppm), both of which were higher in burned soils. The decreased microbial biomass and shift in nitrogen-fixing and ammonia-oxidizing communities were still evident in fire-impacted soils collected 14 months after the fire.

scholarly journals GLOBAL PRODUCTION CONCENTRATION OF MEDIUM DENSITY FIBERBOARD (MDF) (1995 - 2016)

2018 ◽  
Vol 42 (5) ◽  
Author(s):  
Thaisa de Sousa Selvatti ◽  
Luis Antônio Coimbra Borges ◽  
Helena Cristina Carvalho Soares ◽  
Álvaro Nogueira de Souza ◽  
Luiz Moreira Coelho Junior
Keyword(s):  
Gini Index ◽  
Concentration Ratio ◽  
Concentration Index ◽  
Medium Density Fiberboard ◽  
Average Concentration ◽  
Medium Density ◽  
High Concentration ◽  
The World ◽  
Concentration Degree ◽  
Production Concentration

ABSTRACT This papaer analyzed the global MDF production and its concentration degree between 1995 and 2016. In order to measure and analyze this concentration, we used the Concentration Ratio [CR(k)], the Herfindahl-Hirschman Index (HHI), Theil Entropy Index (E), Hall and Tideman Index (HTI), the Comprehensive Concentration Index (CCI), and the Gini Index (G). Global MDF production grew 12.81% p.a. from 1995 to 2016, reaching 99 million m3 at the end of the time series. China took over the hegemony in 2001 and arrived in 2016 with about 60% of the world’s MDF supply. The CR(k) of the global MDF production inferred a high concentration, mainly in the CR(4) from 2009. The CR(8) remained with a moderately high average concentration. During this period more than 90% of the offer was retained in the CR(20). The HHI, E and HTI indices corroborate that there is high concentration in global MDF production, as well as the CCI in the studied period. The inequality indicated by G also presented increasing behavior and was classified as strong and very strong. The concentration indicators were efficient in evaluating the concentration degree of the world MDF supply.

scholarly journals Tracing the Origin of Groundwater Nitrate in an Area Affected by Acid Rain Using Dual Isotopic Composition of Nitrate

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tianming Huang ◽  
Zhenbin Li ◽  
Baoqiang Ma ◽  
Yin Long
Keyword(s):  
Isotopic Composition ◽  
Acid Rain ◽  
Nitrogen Cycle ◽  
Soil Nitrogen ◽  
Average Concentration ◽  
Mountainous Area ◽  
Rock Weathering ◽  
High Concentration ◽  
Groundwater System ◽  
Denitrification Process

Acid rain with a relatively high concentration of ammonium and nitrate can accelerate rock weathering. However, its impact on groundwater nitrate is uncertain. This study evaluated the dual isotopic composition of nitrate (δ15N-NO3- and δ18O-NO3-) from precipitation to groundwater in a rural mountainous area affected by acid rain. The average concentration for NH4+ is 1.25 mg/L and NO3- is 2.59 mg/L of acid rain. Groundwater NO3- concentrations ranged from <0.05 to 11.8 mg/L (baseline), and NH4+ concentrations ranged from 0.06 to 0.28 mg/L. The results show that groundwater δ18O-NO3- values (-4.7‰ to +4.2‰) were lower than the values of rainfall δ18O-NO3- (+24.9‰ to +67.3‰), suggesting that rainfall NO3- contributes little to groundwater NO3-. Groundwater δ15N-NO3- values (+0.1‰ to +7.5‰) were higher than the values of δ15N-NO3- derived from the nitrification of rainfall NH4+ (less than -4.7‰ in the study area), suggesting that nitrification of rainfall NH4+ also contributes little to groundwater NO3-. This implies that rainfall NO3- and NH4+ have been utilized. The dual isotopic composition of nitrate shows that baseline groundwater NO3- is derived mainly from nitrification of soil nitrogen. The denitrification process is limited in the groundwater system. This study shows that the rainfall NO3- and NH4+ contribute little to groundwater NO3-, improving the understanding of the nitrogen cycle in areas with a high concentration of NH4+ and NO3- in rainfall.

Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest

2006 ◽  
Vol 15 (1) ◽  
pp. 37 ◽  
Author(s):  
Eric E. Knapp ◽  
Jon E. Keeley
Keyword(s):  
Sierra Nevada ◽  
Prescribed Burning ◽  
Fire Severity ◽  
Basal Area ◽  
Conifer Forest ◽  
Fuel Loading ◽  
Early Season ◽  
Late Season ◽  
Fuel Loads ◽  
In Fire

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.

scholarly journals Numerical Modeling of Fire Resistance Test as a Tool to Design Lightweight Marine Fire Doors: A Preliminary Study

2020 ◽  
Vol 8 (7) ◽  
pp. 520 ◽  
Author(s):  
Giada Kyaw Oo D’Amore ◽  
Alberto Marinò ◽  
Jan Kašpar
Keyword(s):  
Fire Resistance ◽  
Resistance Test ◽  
Critical Parameters ◽  
Test Procedures ◽  
Element Analysis ◽  
Thermal Bridge ◽  
Fire Resistance Test ◽  
Marine Applications ◽  
In Fire

Finite element analysis (FEA) is employed to simulate the thermo-resistance of a marine fire-proof door in the fire-resistance test defined by the International Code for the Application of Fire Test Procedures (2010 FTP Code) and required by the International Maritime Organization (IMO) for marine applications. The appropriate type of simulation adopted (i.e., steady or unsteady) is discriminated on the basis of a comparison between the numerical results and the experimental data. This appropriate model is used to evaluate the critical parameters affecting fire-proof door performance. A remarkable role of the thermal bridge at the door edges in fire resistance is assessed, along with the parameters that allow its reduction. These findings provide insight into how to design a thinner and lighter fire door.

scholarly journals Evaluation of the quality of drainage sludge in To Lich River basin and the proposal of suitable management solutions

2018 ◽  
Vol 12 (3) ◽  
pp. 113-122
Author(s):  
Tran Duc Ha ◽  
Tran Thuy Anh
Keyword(s):  
Land Use ◽  
Trace Metals ◽  
Sewage Sludge ◽  
Anthropogenic Activities ◽  
National Standards ◽  
High Concentration ◽  
Aquatic Life ◽  
Water Treatment Process ◽  
Dry Seasons ◽  
Cr Concentration

This study aims to examine the characteristics and to assess the hazardous level as well as the reusability of sewage sludge and river sediment from To Lich River (TLR) basin, which is the largest wastewater catchment in Hanoi. Sludge samples were collected from six manholes along Tran Binh Trong (TBT) and Thai Ha (TH) sewers in rainy and dry seasons. Sediment samples were collected from seven sites near principal wastewater and storm water discharging points along TLR upstream in dry season. Parameters, such as pH, humidity, total ash, zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd) in sewage sludge were examined. Trace metals in TLR sediment, e.g. arsenic (As), mercury (Hg), lead (Pb), zinc (Zn), chromium (Cr), and cadmium (Cd) were analyzed. The results of sludge and sediment analysis were then compared with national environmental regulations for hazards and aquatic life preservation, and land use purposes, including QCVN 43:2012/BTNMT, QCVN 50:2013/BTNMT, QCVN 03-MT: 2015/BTNMT. The majority of examined parameters of sewage sludge, except ash content, are higher in dry seasons than in rainy seasons. Regarding hazardous level, all the investigated heavy metals in sewage sludge in dry and rainy seasons, respectively, as followings: 644 and 598 mg.kg-1 Zn, 146.5 and 127.3 mg.kg-1 Cu, 71.2 and 69.5 mg.kg-1 Pb, and 1.51 and 1.46 mg.kg-1 Cd, are below the legislated thresholds, thus, can be considered as nontoxic. Reusability of sewage sludge, however, should be considered since Zn exceeded permissible values for all of land use purposes. The concentration of As (0.659 mg.kg-1), Hg (0.03 mg.kg-1), Pb (4.07 mg.kg-1), Zn (81.3 mg.kg-1), and Cd (0.078 mg.kg-1) meets national standards on hazardous waste, and sludge from water treatment process, as well as to protect aquatic life and to be reused in anthropogenic activities. However, Cr concentration (157 mg.kg-1) is above those legislated thresholds, thus, unsuitable to be reused as land or fertilizer. With high concentration of several trace metals and humidity, drainage sludge from TLR basins should be treated to improve its reusability. Article history: Received 20 March 2018, Revised 05 April 2018, Accepted 27 April 2018

scholarly journals Fort-Dauphin beach sands, south Madagascar: natural radionuclides and mineralogical studies

2020 ◽  
Vol 42 (2) ◽  
pp. 118-129 ◽  
Author(s):  
Hao Duong Van ◽  
Alinanja Lantoarindriaka ◽  
Adam Piestrzyński ◽  
Phan Trong Trinh
Keyword(s):  
Natural Radionuclides ◽  
Natural Radionuclide ◽  
Mineral Resources ◽  
Average Concentration ◽  
High Ratio ◽  
Beach Sand ◽  
High Concentration ◽  
Beach Sands ◽  
Refractory Minerals ◽  
Black Sands

The Fort-Dauphin beach sand placer occurs as black sands on the East-South of Madagascar. The placer contributes 2/3 of the total heavy mineral resources of this country. The major minerals of the deposit are monazite, zircon, quartz, garnet, spinel, sillimanite as non-refractory minerals; ilmenite, anatase, rutile, titanite, leucoxene, pseudorutile and as a refractory one. The average concentration of the ilmenite, monazite, zircon and other minerals is 66.72%, 2.3%, 2.8%, and 28.18% respectively. Ilmenite contains 63 wt.% of TiO2, Zircon - 44 wt.% of ZrO2, Monazite contains 53 wt.% of oxide rare earth elements (REE) and up to 2 wt.% of UO2 and 9 wt.% of ThO2. The total REE in the studied samples was observed high concentration up to 16000ppm and a high ratio of Σ LREE/Σ HREE>31. The principal natural radionuclide in this placer is 232Th with the concentration of 232Th from 2710 to 6000 ppm, 3620 ppm on average while for the 238U from 124 to 340 ppm, 237 ppm on average which are higher than the average of their in Earth’s crust 360 and 70 times respectively.

scholarly journals PHOTOSYNTHETIC PIGMENT CONTENT AS A CONSEQUENTAL RESISTANCE SIGN OF POTATO VARIETIES TO HIGH TEMPERATURE AND MOISTURE LACK

2020 ◽  
Vol 5 (2) ◽  
pp. 8-13
Author(s):  
Aleksei Bakunov ◽  
Aleksei Milekhin ◽  
Sergei Rubtsov ◽  
Sergei Shevchenko
Keyword(s):  
Chlorophyll A ◽  
Photosynthetic Pigments ◽  
Photosynthetic Pigment ◽  
Negative Relationship ◽  
Average Concentration ◽  
Potato Yield ◽  
Chlorophyll B ◽  
High Concentration ◽  
Middle Volga Region ◽  
Plant Nursery

The aim of the research is increasing potato yield in dry conditions of the Middle Volga region. The research was carried out on the experimental field of the Samara Scientific Research Institute of Agriculture – branch of the Sa-mara Research Center of the Russian Academy of Sciences. The variety testing plant nursery included 28 varieties of potatoes of domestic selection. Udacha, Zhigulevsky, Arosa and Gala breeds were the standard varieties. The plant material was planted out in two replications with 25 plants in each. To determine the content of photosynthetic pigments, extracts were prepared from ten potato leaves of each breed in 100% acetone. Measurements were per-formed by spectrophotometry. To measure the amount of chlorophyll a, the wavelength of 665 nm, chlorophyll b – 649 nm, and carotenoids – 440 nm were used. The concentration of pigments was determined by using Wettstein formulas. When harvesting, the potato yield was taken into account. The average concentration of chlorophyll a in the studied breeds was 0.92 mg/g, the average concentration of chlorophyll b was 0.62 mg/g, and one of carote-noids was 0.27 mg/g. Potato breeds with high concentration of photosynthetic pigments were identified. A reliable average dependence of the yield of potato breeds on the concentration of chlorophyll b in plants was revealed. The correlation coefficient was 0.42. There is no reliable dependence tested of yield on the concentration of chlorophyll a and carotenoids. Potato productivity is associated with a significant negative relationship with the ratio of both a and b chlorophyll concentrations. The most highly productive varieties were characterized by a high content of two varieties of chlorophyll. A high concentration of chlorophyll b or a minimum ratio of chlorophyll a and b concentra-tions can be tentatively recommended as a consequential sign for identifying potato breeds that are highly adapted to high air temperature and insufficient moisture.

scholarly journals Estimation Des Concentrations Et Cartographie De La Dynamique Des Polluants Atmosperiques Particulaires Dans La Ville D’abidjan

2021 ◽  
Vol 17 (43) ◽  
pp. 116
Author(s):  
N’Guessan Bi Vami Hermann ◽  
Lazile Stephanie ◽  
Loukou Jerome André ◽  
Saley Mahaman Bachir ◽  
Kouadio Affian
Keyword(s):  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Average Concentration ◽  
High Concentration ◽  
Cote D’Ivoire ◽  
Health Security ◽  
Côte D'ivoire ◽  
West Part ◽  
Pollution Atmosphérique ◽  
Landsat Satellite

En Côte d’Ivoire, la gestion et la sécurité sanitaire liée à la pollution atmosphérique revet un grand interêt . Dans ce même élan de gestion de la qualité de l’air l’OMS a fixé un seuil d’émission que les pays doivent intégrer dans leur mode de gestion. Cependant, dans les villes de grandes concentrations comme Abidjan il est parfois difficile de maitriser les paramètres d’émissions. L’objectif de cette étude est donc d’estimer les concentrations des polluants atmospreriques particulaires PM2.5 et ensuite cartographier la dynamique de ces polluants de 2015 à 2020. Pour atteindre cet objectif , les données de l’imagerie satellitaire LANDSAT ont été utilisées. Il a s’agit de calculer les réflectances de surfaces et les réflectances au sommet de l’atmosphère. Le but de ces calculs était de déduire les réflectances atmosphériques. En considérant la relation étroite existence entre les PM2.5 et la réflectance atmosphérique un modèle de régression linéaire a été conidéré pour déduire les PM2.5. Les résultats ont montré que les concentrations des PM2.5 sont de façon générale au-dessus du seuil de l’OMS. Ces valeurs sont de 31 μg/m3 en janvier 2015 , de 36 μg/m3 en janvier 2016 , de 32 μg/m3 en décembre 2016, de 33 μg/m3 en janvier 2019 et de 33 μg/m3 en janvier 2020. Cela donne une concentration moyenne de 33 μg/m3. Les communes de Yopougon Nord, Abobo Ouest, Cocody ouest et Port-Bouet Est sont les zones les plus pollués avec des concentrations allant de 26 à 49 μg/m3. In Côte d'Ivoire, management and health security related to air pollution are of great interest. In this same approach to air quality management, WHO has set an emission threshold that countries must integrate into their management method. However, in cities with a high concentration like Abidjan, it is sometimes difficult to control the emission parameters. The objective of this study is therefore to estimate the concentrations of particulate air pollutants PM2.5 and then to map the dynamics of these pollutants from 2015 to 2020. To achieve this objective, data from LANDSAT satellite imagery were used. . This involves calculating the surface reflectances and the reflectances at the top of the atmosphere. The purpose of these calculations was to deduce atmospheric reflectances. Given the close relationship between PM2.5 and atmospheric reflectance, a linear regression model was considered to derive PM2.5. The results showed that PM2.5 concentrations are generally above the WHO threshold. These values are 31μg /m3 in January 2015, 36 μg / m3 in January 2016, 32 μg / m3 in December 2016, 33 μg / m3 in January 2019 and 33 μg / m3 in January 2020. This gives an average concentration of 33 μg / m3. The cities of Yopougon noth part, Abobo west part, Cocody west part and Port-Bouet east part are the most polluted areas with concentrations ranging from 26 to 49 μg / m3.

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