rss_2.0Journal of Hydrology and Hydromechanics FeedSciendo RSS Feed for Journal of Hydrology and Hydromechanicshttps://sciendo.com/journal/JOHHhttps://www.sciendo.comJournal of Hydrology and Hydromechanics Feedhttps://sciendo-parsed-data-feed.s3.eu-central-1.amazonaws.com/63dde1753ef6e2243de7ca3e/cover-image.jpghttps://sciendo.com/journal/JOHH140216Effect of water surface slope and friction slope on the value of the estimated Manning’s roughness coefficient in gravel-bed streamshttps://sciendo.com/article/10.2478/johh-2022-0041<abstract> <title style='display:none'>Abstract</title> <p>The aim of the study was to assess the possibility of using the empirical formulas to determine the roughness coefficient in gravel-bed streams, the bed slopes of which range from 0.006 to 0.047. Another aim was to determine the impact of taking into account the conditions of non-uniform flow on the application of these formulas and to develop the correlation relationships between the roughness coefficient and water surface slope and also between the roughness coefficient and friction slope in order to estimate the roughness coefficient <italic>n</italic> in gravel-bed streams.</p> <p>The studies were conducted in eight measuring sections of streams located in the Kraków-Częstochowa Upland, southern Poland. The roughness coefficient <italic>n</italic><sub>0</sub> for these sections was calculated from the transformed Bernoulli equation based on the results of surveys and hydrometric measurements. The values of <italic>n</italic><sub>0</sub> were compared with the calculation results obtained from fourteen empirical formulas presenting the roughness coefficient as a function of slope.</p> <p>The Lacey, Riggs, Bray and Sauer formulas were found to provide an approximate estimate of the <italic>n</italic> value, while the best roughness coefficient estimation results were obtained using the Riggs formula. It was also found that taking into account the non-uniform flow and using the friction slope in the formulas instead of the bed slope or water surface slope did not improve the estimated values of the roughness coefficient using the tested formulas. It was shown that the lack of differences in the RMSE and MAE error values calculated for the developed correlation equations between the roughness coefficient and the friction slope or with the water surface slope also indicate no influence of the assumed friction slope or water surface slope on the value of the estimated roughness coefficient.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00412023-02-04T00:00:00.000+00:00Accuracy of radar-estimated precipitation in a mountain catchment in Slovakiahttps://sciendo.com/article/10.2478/johh-2022-0037<abstract> <title style='display:none'>Abstract</title> <p>Accurate estimation of precipitation in mountain catchments is challenging due to its high spatial variability and lack of measured ground data. Weather radar can help to provide precipitation estimates in such conditions. This study investigates the differences between measured and radar-estimated daily precipitation in the mountain catchment of the Jalovecký Creek (area 22 km<sup>2</sup>, 6 rain gauges at altitudes 815–1900 m a.s.l.) in years 2017–2020. Despite good correlations between measured and radar-based precipitation at individual sites (correlation coefficients 0.68–0.90), the radar-estimated precipitation was mostly substantially smaller than measured precipitation. The underestimation was smaller at lower altitude (on average by –4% to –17% at 815 m a.s.l.) than at higher altitudes (–35% to –59% at 1400–1900 m a.s.l.). Unlike measured data, the radar-estimated precipitation did not show the differences in precipitation amounts at lower and higher altitudes (altitudinal differences). The differences between the measured and radar-estimated precipitation were not related to synoptic weather situations. The obtained results can be useful in preparation of more accurate precipitation estimates for the small mountain catchments.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00372023-02-04T00:00:00.000+00:00Discharge coefficient, effective head and limit head in the Kindsvater-Shen formula for small discharges measured by thin-plate weirs with a triangular notchhttps://sciendo.com/article/10.2478/johh-2022-0040<abstract> <title style='display:none'>Abstract</title> <p>The paper deals with the determination of the discharge coefficient, effective head and newly the limit head in the Kindsvater-Shen formula for the determination of a relatively small discharge of clear water using a thin-plate weir with a triangular notch. The determination of the discharge coefficient, effective head and limit head is based on extensive experimental research and is verified by previous measurements by other authors. The experimental research was characterised by a large range of notch angles (from 5.25° to 91.17°), weir heights (from 0.00 m to 0.20 m), and water temperatures (from 15 °C to 45 °C), as well as a focus on relatively small heads (from 0.02 m to 0.18 m), which is where the strengths of the Kindsvater-Shen formula stand out. The experimental research supplemented existing knowledge about the overflow occurring with small heads and small weir notch angles. The newly determined dependencies in the Kindsvater-Shen formula extended its applicability to weirs with small notch angles and newly enabled the determination of the limit head, which restricts its applicability in the determination of small discharges.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00402023-02-04T00:00:00.000+00:00Effects of pore size and pore connectivity on trapped gas saturationhttps://sciendo.com/article/10.2478/johh-2022-0042<abstract> <title style='display:none'>Abstract</title> <p>Trapped or residual air (or gas) is known to affect the multiphase hydraulic properties of both soils and rocks. Trapped air is known to impact many vadose zone hydrologic applications such as infiltration and flow in the capillary fringe, but is also a major issue affecting recoverable oil reserves. Although many studies have focused on the relationship between porosity and trapped gas saturation (<italic>S</italic><italic><sub>gt</sub></italic>) in sandstones, far fewer studies have been carried out for carbonate rocks. This work aims to analyze the influence of porous media properties on trapped gas saturation in carbonate rocks. For this we used thirteen Indiana Limestone and Silurian dolomite rock samples from the USA, and several coquinas from the Morro do Chaves formation in Brazil. Pore size distributions were obtained for all samples using Nuclear Magnetic Resonance (NMR), and Mercury Injection Capillary Pressure (MICP) data from three of the samples to determine their pore throat size distributions. Additionally, 3D microtomography (microCT) images were used to quantify macropore profiles and pore connectivities. Results indicate a lower capacity of gas trapping in carbonate rocks in which micro- and mesopores predominate. Results also indicate that in carbonate rocks, pore size exerts a greater influence on the ability of gas trapping compared to pore connectivity, so that rocks with a predominance of macropores have greater capacity for gas trapping, even when the macropores are well interconnected. These findings show that pore characteristics very much affect the processes governing gas trapping in carbonate rocks, and indirectly the multiphase hydraulic properties and recoverable oil reserves of carbonate rock reservoirs.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00422023-02-04T00:00:00.000+00:00Soil management and seasonality impact on soil properties and soil erosion in steep vineyards of north-western Croatiahttps://sciendo.com/article/10.2478/johh-2022-0038<abstract> <title style='display:none'>Abstract</title> <p>In order to mitigate vineyard degradation, we study different soil management to obtain the most suitable practices. To study the effects of water erosion on vineyards, a rainfall experiment (58 mm h<sup>-1</sup> for 30 min) was applied on Anthrosols in humid conditions to assess the impact of treatment (Tilled, Straw and Grass) and season (Spring and Summer). Higher bulk density (BD) and soil water content (SWC) were on the Straw treatment in the Spring period. Also, the Tilled and Grass treatment noticed higher mean weight diameter (MWD) and water-stable aggregates (WSA). In the Summer, BD, SWC and MWD were significantly higher on the Grass treatment. Higher values of time to ponding (TP) and time to runoff (TR) in Spring were recorded on the Grass treatment, Runoff was higher on the Straw treatment. Higher sediment concentration (SC) and soil loss (SL) were noticed during the Tilled treatment. In the Summer period, TP was higher on the Straw treatment, while TR and Runoff were higher on the Straw, SC and SL on the Tilled treatment. This study confirms the positive effects of grass cover and straw mulching as a sustainable agricultural practice in sloped vineyards of north-western Croatia.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00382023-02-04T00:00:00.000+00:00Effect of gravel content on soil water retention characteristics and thermal capacity of sandy and silty soilshttps://sciendo.com/article/10.2478/johh-2023-0001<abstract> <title style='display:none'>Abstract</title> <p>The presence of gravel in soils modifies the porosity, pore connectivity and pore size distribution in the soil matrix as well as the soil matrix-gravel interfaces. The aim of the present study is to investigate the effect of relative volume of gravel in samples with gravel mass fractions of 5,10, 20 wt% and varying bulk densities (1.3, 1.45, 1.55, 1.60, 1.65 g cm<sup>–3</sup>) on (i) total porosity, field capacity, plant available water holding capacity, (ii) pore size distribution and (iii) thermal capacity of repacked sandy and silty soils. The focus of the study was to determine if laboratory measured soil water retention curves considering (i), (ii), and (iii) can be predicted by a gravel-based weighting factor, R<sub>v</sub>, considering comprehensive significance tests. The sand-gravel mixtures show a decrease in the volume fractions of macropores and wide cores pores with an increase in the gravel contents, while the silt-gravel mixtures show an opposite trend. The root mean square errors (RMSE) between measured and fitted volumetric water contents, θ, between 0.006 and 0.0352 and between 0.002 and 0.004 for R<sub>v</sub>-weighted volumetric water contents indicate that the van Genuchten-based Peters-Durner-Iden (PDI) model is appropriate for fitting. The soil water retention curves with mass gravel contents of up to 10 wt% for silt and 20 wt% for sand can be well predicted by weighting factors (relative volume of rock fragments) in the range between 0.045 and 0.058 for silt, and between 0.112 and 0.119 for sand. The results also indicate a decrease in the Rv-weighted saturated, c<sub>vsat</sub>, and dry, c<sub>vdry</sub>, thermal capacity with an increase in the gravel contents for both soils. Further investigations are needed to examine if and whether measured sand- and silt-gravel mixtures with mass gravel contents below 10 % or rather 20 % can be predicted with a weighting factor.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2023-00012023-02-04T00:00:00.000+00:00A novel H-shape fishway with excellent hydraulic characteristicshttps://sciendo.com/article/10.2478/johh-2022-0026<abstract> <title style='display:none'>Abstract</title> <p>Fishway design not only takes into account the swimming abilities of target fishes, but also considers the hydrodynamic characteristics within the fishway. In this study, the flow fields of one vertical-slot fishway (<italic>i.e.</italic> VSF), five T-shape fishways (<italic>i.e.</italic> TSF-1~TSF-5) and two H-shape fishways (i.e. HSF-1 and HSF-2) are numerically simulated by solving the three-dimensional Reynolds-averaged Navier-Stokes equations and the K-Omega-SST turbulence model. The numerical results clearly indicate that the hydrodynamic properties of HSF-2 are overall superior to the remaining seven cases, in terms of the time-averaged flow pattern, the time-averaged velocity magnitude, the depth-mean time-averaged velocity magnitude along the vertical-slot section, the volume percentages of the time-averaged velocity magnitude less than some critical values, and the distribution of the time-averaged turbulent kinetic energy. Therefore, HSF-2 is more friendly for fishes with relatively smaller sizes and weaker swimming capacities to transfer upstream. The novel HSF-2 is firstly proposed in this paper, and it is naturally designed during the process of improving the flow regime. Furthermore, the generalizability of the superiority of HSF-2 over VSF and the original T-shape fishway (<italic>i.e.</italic> TSF-1) has been exhibited with the aid of the numerical results of four operating conditions (<italic>i.e. Q</italic> = 400 L/s, 600 L/s, 800 L/s and 1000 L/s).</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00262023-02-04T00:00:00.000+00:00Evaluation of a general model for multimodal unsaturated soil hydraulic propertieshttps://sciendo.com/article/10.2478/johh-2022-0039<abstract> <title style='display:none'>Abstract</title> <p>Many soils and other porous media exhibit dual- or multi-porosity type features. In a previous study (Seki et al., 2022) we presented multimodal water retention and closed-form hydraulic conductivity equations for such media. The objective of this study is to show that the proposed equations are practically useful. Specifically, dual-BC (Brooks and Corey)-CH (common head) (DBC), dual-VG (van Genuchten)-CH (DVC), and KO (Kosugi)<sub>1</sub>BC<sub>2</sub>-CH (KBC) models were evaluated for a broad range of soil types. The three models showed good agreement with measured water retention and hydraulic conductivity data over a wide range of pressure heads. Results were obtained by first optimizing water retention parameters and then optimizing the saturated hydraulic conductivity (<italic>K</italic><italic><sub>s</sub></italic>) and two parameters (<italic>p</italic>, <italic>q</italic>) or (<italic>p</italic>, <italic>r</italic>) in the general hydraulic conductivity equation. Although conventionally the tortuosity factor <italic>p</italic> is optimized and (<italic>q</italic>, <italic>r</italic>) fixed, sensitivity analyses showed that optimization of two parameters (<italic>p</italic> + <italic>r</italic>, <italic>qr</italic>) is required for the multimodal models. For 20 soils from the UNSODA database, the average <italic>R</italic><sup>2</sup> for log (hydraulic conductivity) was highest (0.985) for the KBC model with <italic>r</italic> = 1 and optimization of (<italic>K</italic><italic><sub>s</sub></italic>, <italic>p</italic>, <italic>q</italic>). This result was almost equivalent (0.973) to the DVC model with <italic>q</italic> = 1 and optimization of (<italic>K</italic><italic><sub>s</sub></italic>, <italic>p</italic>, <italic>r</italic>); both were higher than <italic>R</italic><sup>2</sup> for the widely used Peters model (0.956) when optimizing (<italic>K</italic><italic><sub>s</sub></italic>, <italic>p</italic>, <italic>a</italic>, ω). The proposed equations are useful for practical applications while mathematically being simple and consistent.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00392023-02-04T00:00:00.000+00:00Proposal of a new method for drought analysishttps://sciendo.com/article/10.2478/johh-2022-0030<abstract> <title style='display:none'>Abstract</title> <p>Below-average precipitation and above-average air temperature are important factors in the occurrence and intensity of drought. In the context of global climate change, air temperature increase, as a key climatological parameter, has to be considered when calculating the drought index. We introduce a new method of drought analysis, relying on standardized values of precipitation and mean air temperatures for a certain period. The standardized value is calculated by subtracting the average value for each period from each measured value and dividing the obtained value by the standard deviation of the sample. Next, the New Drought Index (NDI) is calculated by subtracting the standardized temperature value from the standardized precipitation value. NDI values were determined for the monthly and annual precipitation time series and mean monthly and annual air temperatures measured at the stations Split-Marjan and Zagreb-Grič between 1948 and 2020. The NDI indicates that the risk of drought has intensified significantly in recent decades, which may be related to the effect of global warming.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00302023-02-04T00:00:00.000+00:00Reconstruction of the 1974 flash flood in Sóller (Mallorca) using a hydraulic 1D/2D modelhttps://sciendo.com/article/10.2478/johh-2022-0027<abstract> <title style='display:none'>Abstract</title> <p>Flash flood events are common in the Mediterranean basin, because of a combination of rugged coastal topography and climatological characteristics. The Balearic Islands are a flood-prone region with the research area, Sóller (Mallorca) being no exception. Between 1900 and 2000, Sóller experienced 48 flash floods with 17 categorised as catastrophic. In Sóller, the local surface water network comprises ephemeral streams. These are natural water networks that only carry water during periods of intense rainfall. Using the available evidence from the 1974 flash flood, this research used Flood Modeller to simulate the event. The research developed a one-dimensional (1D) and a one-dimensional two-dimensional (1D-2D) model that assisted in the understanding of the behaviour of the ephemeral stream during the flood. Analysis of hydraulic parameters such as water flow, depth and velocity provided an appreciation of the interaction between the channel and floodplain. Model development aims to forecast the impending impacts of climate change and urbanisation.</p> <p>The results suggest that the characteristics of Sóller’s catchment area naturally encourage flash flooding and hence can be deemed a flashy catchment. The model demonstrates that the interaction between the channel and floodplain relies heavily on surface roughness of both areas. The model proves that if flood intensity increases with climate change, the extent of flooding and consequently the damage will become more severe.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00272023-02-04T00:00:00.000+00:00Changes in organic molecular marker signatures in soils amended with biochar during a three-year experiment with maize on a Fluvisolhttps://sciendo.com/article/10.2478/johh-2022-0025<abstract> <title style='display:none'>Abstract</title> <p>Biochar is widely used as a soil amendment to improve soil properties and as a tool to absorb net carbon from the atmosphere. In this study we determined the signatures of organic molecular markers in soil following the incorporation of 5 and 10 t/ha biochar in a Fluvisol, cultivated with maize at the experimental field of the ISSAPP “N. Poushkarov” institute in Bulgaria. The <italic>n-</italic>alkane distribution in the biochar treated soils was uni- or bimodal maximizing at n-C17 alkane, n-C18 or C18 branched alkanes, i.e. there was an imprint of biomass burning, e.g. from the biochar due to predominance of short chain (&lt; C20) homologues and increased microbial activity (presence of branched alkanes). This is also confirmed by the values for the average chain length (ACL) of n-alkanes which indicated prevalence of homologues of shorter chain (20–21 C atoms) in the variants of longer biochar residence time. There was evidence of trans-13-docosenamide, which originated from biochar. Fatty acids and fatty alcohols distributions also implicate microbial contribution to soil organic matter (SOM), supporting the suggestion that biochar addition can improve soil microbiological status.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00252022-11-16T00:00:00.000+00:00Hydrologic recovery after wildfire: A framework of approaches, metrics, criteria, trajectories, and timescaleshttps://sciendo.com/article/10.2478/johh-2022-0033<abstract> <title style='display:none'>Abstract</title> <p>Deviations in hydrologic processes due to wildfire can alter streamflows across the hydrograph, spanning peak flows to low flows. Fire-enhanced changes in hydrologic processes, including infiltration, interception, and evapotranspiration, and the resulting streamflow responses can affect water supplies, through effects on the quantity, quality, and timing of water availability. Post-fire shifts in hydrologic processes can also alter the timing and magnitude of floods and debris flows. The duration of hydrologic deviations from a pre-fire condition or function, sometimes termed hydrologic recovery, is a critical concern for land, water, and emergency managers. We reviewed and summarized terminology and approaches for defining and assessing hydrologic recovery after wildfire, focusing on statistical and functional definitions. We critically examined advantages and drawbacks of current recovery assessment methods, outline challenges to determining recovery, and call attention to selected opportunities for advancement of post-fire hydrologic recovery assessment. Selected challenges included hydroclimatic variability, post-fire land management, and spatial and temporal variability. The most promising opportunities for advancing assessment of hydrologic recovery include: (1) combining statistical and functional recovery approaches, (2) using a greater diversity of post-fire observations complemented with hydrologic modeling, and (3) defining optimal assemblages of recovery metrics and criteria for common hydrologic concerns and regions.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00332022-11-16T00:00:00.000+00:00Heat–induced changes in soil properties: fires as cause for remobilization of chemical elementshttps://sciendo.com/article/10.2478/johh-2022-0024<abstract> <title style='display:none'>Abstract</title> <p>Exposure of soil constituents to elevated temperatures during wildfire can significantly affect their properties and consequently, increase the mobility of the bound contaminants. To estimate the potential of wildfires to influence metal remobilization from the burned soil due to the changes in cation exchange capacity (CEC) after organic matter combustion and mineral alteration and degradation, changes in soil properties after exposure to different temperatures was investigated. This was accomplished through analysis of geochemical, mineralogical and surface physicochemical properties of a soil sample exposed to different temperatures in a laboratory. Heating the soil sample at 200 °C, 500 °C and 850 °C resulted in an increase in pH (from 5.9 to 12.3), decrease in cation exchange capacity (from 47.2 to 7.3 cmol<sub>+</sub>kg<sup>−1</sup>) and changes in the specific surface area (observed only at 500 °C), that are associated with structural modifications of clay minerals and ferromagnetic minerals. Extraction analysis showed the increase in the concentration of almost all analysed elements (Al, Cd, Co, Cr, Fe, Mn and Zn) in soil eluates. The observed increase, following high– temperature heating (500 °C and 850 °C), was as much as 15 times higher (e.g., Al), compared to the native soil sample (25 °C). This strongly indicates that wildfire can act as a trigger for remobilization of heavy metals.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00242022-11-16T00:00:00.000+00:00Variability of soil properties with fire severity in pine forests and reforested areas under Mediterranean conditionshttps://sciendo.com/article/10.2478/johh-2022-0028<abstract> <title style='display:none'>Abstract</title> <p>It is well known how fires affect the properties of forest soils depending on its severity. A better understanding of the magnitude of these impacts is essential to setup effective management actions after fire against the losses of soil and biodiversity. However, physical, chemical and biological processes in burnt soils are complex, resulting in a diversity of fire-induced changes, as acknowledged in many literature studies. Moreover, these changes may be even variable between natural forests and reforested areas. This study explores the changes in the most important soil properties with fire severity, from low to high. The main chemical parameters of soils were measured after field sampling in different pine forests (burnt natural stands, reforested areas as well as unburnt sites) of Castilla La Mancha (Central Eastern Spain). In comparison to the unburnt soils, the investigation has shown in the burnt areas: (i) no evident changes in soil pH at all fire severities, except in natural stands burnt at a very high severity (showing an increase of about 10%); (ii) increases in the organic carbon content (by about 70%) of soils burnt at a moderate fire severity under both forest ecosystems, and in reforested areas at very high fire severities (+95%); (iii) small differences in the nitrogen content of soil, except for a significant increase measured in soils burnt at an moderate fire severity under both the natural pine stand and reforested area (about +300%); (iv) a limited variability of the phosphorous content in the soil, with only an increase in soils under natural pine stands burnt at moderate fire severity (by 250%); (v) increases in magnesium and potassium contents in soils burnt at the highest fire severities for both land conditions, and decreases in calcium content in reforested areas burnt at the highest severity. Due to some negative impacts (increase in pH and decrease in organic carbon), the implementation of post-fire management actions at natural pine stands burnt at the highest fire severity should be a priority over reforested areas. Overall, this study did not show a straightforward pattern between soil properties, fire severity and land condition. This means that other parameters (for instance, the hydrological properties of soils) that were not explored in this investigation could have played an important role, and therefore must be taken into consideration when defining post-fire management actions.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00282022-11-16T00:00:00.000+00:00An exploratory study into ash mobilization using lysimetershttps://sciendo.com/article/10.2478/johh-2022-0035<abstract> <title style='display:none'>Abstract</title> <p>Wildfires burn vegetation and leave the resultant organic and inorganic ash into the soil surface. Depending on the temperatures and burn durations, the quantity and type of ash can vary widely. Ash mobilization following wildfire is a topic of major concern, since it may result in contamination of surface water bodies within and downstream of the burnt areas.</p> <p>The present study aims to analyse the influence of black and white ash on surface runoff, leachate and total erosion and erosion of organic matter by running a field experiment along 6 weeks, using three replicate lysimeters with control soil, soil with addition of black ash and soil with addition of white ash. There was some suggestion but no statistical evidence that black ash reduced overland flow generation during the initial rainfall events, while black ash was found to increase sediment and organic matter losses by overland flow in a statistically significant manner. This was not during the initial rainfall events and, therefore, not directly related to the presence of a homogenous cover of a well-defined ash layer on the soil surface.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00352022-11-16T00:00:00.000+00:00Introduction to the special issue on fire impacts on hydrological processeshttps://sciendo.com/article/10.2478/johh-2022-0036ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00362022-11-16T00:00:00.000+00:00Intensity and persistence of water repellency at different soil moisture contents and depths after a forest wildfirehttps://sciendo.com/article/10.2478/johh-2022-0031<abstract> <title style='display:none'>Abstract</title> <p>The Mediterranean mixed coniferous and broad-leaved forest of Moarda (Palermo) was affected by a large wildfire in summer 2020. In spring 2021, burned and unburned loam soil sites were sampled and the water drop penetration time (WDPT) and ethanol percentage (EP) tests applied to assess the influence of wetting-drying processes and soil water content on post-fire soil water repellency (SWR) as well as its vertical distribution. According to the WDPT test, the surface layer of the natural unburned soils was severely hydrophobic at intermediate soil water contents roughly corresponding to wilting point and SWR reduced either for very dry conditions (air- or oven-dried conditions) or wetter conditions close to field capacity. For these soils, EP test yielded results in agreement with WDPT. An influence of the wetting/drying cycle was detected as, for a given soil water content, WDPT was generally higher for the drying than the wetting process. The surface of burned soils was always wettable independently of the soil water content. The vertical distribution of SWR was modified by wildfire and the maximum hydrophobicity layer, that was located at the surface of the unburned soils, moved to a depth of 2–4 cm in the soils of burned sites. The results confirmed that wildfire can induce destruction of soil water repellency (SWR) naturally occurring at the surface of forest soils and create a shallow hydrophobic layer that may increase overland flow and erosion risk.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00312022-11-16T00:00:00.000+00:00Fire-induced changes in soil properties depend on age and type of forestshttps://sciendo.com/article/10.2478/johh-2022-0034<abstract> <title style='display:none'>Abstract</title> <p>Wildfires affect different physical, chemical, and hydraulic soil properties, and the magnitude of their effects varies depending on intrinsic soil properties and wildfire characteristics. The objectives of this study are: to estimate the impact of heating temperature (50–900°C) on the properties of sandy soil (Arenosol) taken in 1) coniferous forests (Scots pine <italic>Pinus sylvestris</italic>) of different ages (30 and 100 years); and 2) coniferous (Scots pine <italic>Pinus sylvestris</italic>) and deciduous (alder <italic>Alnus glutinosa</italic>) forests of the same age (30 years). The forests are located in the central part of the Borská nížina lowland (western Slovakia), and the properties treated were soil organic carbon content (SOC), pH, and soil water repellency (measured in terms of water drop penetration time, WDPT). It was found that the impact of heating temperature on the properties of sandy soil is great and depends on both the age and type of forest. The SOC value decreased unevenly with temperature in all three soils, and it was higher in the 30-year-old deciduous forest soil than in the 30-year-old coniferous forest soil. The value of pH increased monotonously with temperature from 200 °C, and it was higher in 30-year-old coniferous forest soil than in the 100-year-old coniferous forest soil. SOC and WDPT in the 100-year-old coniferous forest soil were higher than SOC and WDPT in the 30-year-old coniferous forest soil. Results obtained (decrease in SOC, disappearance of SWR after heating to 400 °C, and increase in pH from heating temperature 200 °C) bring important information for post-fire vegetation restoration and post-fire management of Central European forests established on sandy soil.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00342022-11-16T00:00:00.000+00:00Effects of prescribed fire on topsoil properties: a small-scale straw burning experimenthttps://sciendo.com/article/10.2478/johh-2022-0032<abstract> <title style='display:none'>Abstract</title> <p>A grassland was burned to investigate how a short prescribed fire affected soil physical and hydraulic properties, soil water balance, and emergent vegetation. Three years before the experiment at Řisuty, Czech Republic, the grassland was re-established on arable soil. At the experimental site there is a weather station and sensors measuring soil temperature and moisture at three different depths. The 5 m × 5 m burned plot was compared to a nearby unburned reference location. The loamy Cambisol soil was not water-repellent. 250 m<sup>2</sup> of sun-dried grass was raked and burned at the burned plot. The fire lasted approximately 15-minute and reached 700 °C. Soil samples were taken immediately after the fire and weekly to monthly thereafter to quantify organic carbon content, soil structure stability, hydraulic conductivity, bulk density, and texture. According to the research results, it appears that temporary burning improved the hydraulic properties of the topsoil. The fire plot’s infiltration capacity was increased, and soil water content was higher than the control plot throughout the year, providing suitable habitat for colonizing vegetation. The results suggest that small-scale controlled biomass burning can be risk-free to the soil ecosystem and may even temporarily improve the hydraulic properties of the upper soil layer.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00322022-11-16T00:00:00.000+00:00Open data application to evaluate exposure of wildfire to water resources: A case study in Johor, Malaysiahttps://sciendo.com/article/10.2478/johh-2022-0029<abstract> <title style='display:none'>Abstract</title> <p>Climate change impacts wildfire events as well as water availability. Exposure of water resources to wildfire can reduce water quality supplied to humans and resulting health problems. On the other hand, water resources such as rivers and ponds are essential in wildfire firefighting. This paper intended to assess spatially the exposure of water resources to wildfire. A case study in Johor, Malaysia is utilised to asses and determine locations of water bodies in an area which are vulnerable to wildfire. Post wildfire runoff water can contaminate water resources. Fire data collected by MODIS from 2000–2020 are used to create a hotspot map. Water resources and waterbody data originated from Department of Surveying and Mapping Malaysia used to identify the stream and dams that are exposed to wildfire. 5 class exposure level has been set to show the degree of closeness of water resources to wildfire hotspot area. Using the spatial analysis method, low to high level of potential wildfire-water exposures were able to be locate. Analysis shows, 7% of Johor’s water sources is exposed to medium levels of wildfire, while just 1% is exposed to the highest levels. The majority of the streams have very low levels of exposure. In addition, the wildfire-water exposure map aids in first respondent preparedness and planning.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/johh-2022-00292022-11-16T00:00:00.000+00:00en-us-1