Wildfire Impacts on Soil-Erosion and Hydrology in Wet Mediterranean Forest, Portugal

The Agueda Basin, north-central Portugal is comparatively wet (rainfall, 1600-1800 mm/yr) with frequent, relatively large storms in autumn and winter yet the summer drought is sufficiently long and consistent for frequent forest wildfires. This paper discusses wildfire impacts in such a wet Mediterranean environment on soil hydrophobicity, infiltration capacity, overland flow coefficients, soil loss, rainsplash detachment and small-scale ground level changes for Eucalyptus globulus and Pinus pinaster forest: (1) 0-2 years after fire ('new' burn); (2) 3-4 years after fire ('old' burn); and (3) 'mature' (or long unburnt) sites. For 'new' burn sites, rainsplash detachment rates are an order of magnitude and soil losses two orders of magnitude higher than for 'old' burn sites and both are two orders of magnitude higher than for 'mature' sites. Soils are hydrophobic in all three categories of sites, but infiltration capacities are lower at 'new' burn and 'old' burn than at 'mature' sites. Overland flow coefficients on long unburnt sites were low while on burnt sites they were high and tended to be higher for summer and autumn than for winter and spring, implying enhanced hydrophobicity under summer drought conditions, causing decreased infiltration capacity and increased overland flow. The distinctiveness of fire effects on soil erosion and hydrology in this wet Mediterranean environment and implications for post-fire management are discussed.

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Erosion and sediment transport models with reference to the needs of small scale

10.5194/egusphere-egu21-5513 ◽

2021 ◽

Author(s):

Ahsan Raza ◽

Thomas Gaiser ◽

Muhammad Habib-Ur-Rahman ◽

Hella Ahrends

Keyword(s):

Soil Erosion ◽

Overland Flow ◽

Model Development ◽

Agroforestry Systems ◽

Specific Model ◽

Small Scale ◽

Field Scale ◽

Erosion Prediction ◽

Dynamic Components ◽

Output Information

<p>Information on field scale soil erosion and related sedimentation process is very important for natural resource management and sustainable farming. Plenty of models are available for study of these processes but only a few are suitable for dynamic small scale soil erosion assessments. The available models vary greatly in terms of their input requirements, analysis capabilities, process [t1] complexities, spatial and temporal scale of their intended use, practicality, the manner they represent the processes, and the type of output information they provide. The study aims in examining, theoretically, 51 models classified as physical, conceptual, and empirical based on their representation of the processes of soil erosion. The literature review shows that there is no specific model available for soil erosion prediction under agroforestry systems. &#160;&#160;It is further suggested that models like EPIC, PERFECT, GUEST, EPM, TCRP, SLEMSA, APSIM, RillGrow, and CREAMS can be potentially used for soil erosion assessment at plot/field scale at daily time steps. Most of these models are capable to simulate the soil erosion process at small scale; further model development is needed regarding their limitations with respect to components interaction i.e., rainfall intensity, overland flow, crop cover, and their difficulties in upscaling. The research suggested that SIMPLACE network can provide modules with LintulBiomass, HillFlow, Runoff to develop new dynamic components to simulate overland flow and soil erosion incorporating improved upscaling capabilities</p>

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Simulation of Runoff for Varying Mulch Coverage on a Sloped Surface

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.409-410.339 ◽

2013 ◽

Vol 409-410 ◽

pp. 339-343 ◽

Cited By ~ 1

Author(s):

Su Fang Cui ◽

Ying Hua Pan ◽

Quan Yuan Wu ◽

Zhen Hua Zhang ◽

Bao Xiang Zhang

Keyword(s):

Soil Erosion ◽

Rainfall Intensity ◽

Overland Flow ◽

Soil Surface ◽

Northwest China ◽

Slope Gradient ◽

Soil Infiltration ◽

Infiltration Capacity ◽

Coverage Ratio ◽

Runoff Volume

The use of thin plastic film to cover slope surfaces can lead to slope runoff and soil erosion in Loess hilly areas in northwest China. Three main factors (slope, rainfall intensity, and coverage ratio) were selected to analyze variations in runoff dynamics for a Lou soil surface and to obtain a theoretical foundation for practical application. The results indicate that for a fixed rainfall intensity and coverage ratio, a critical slope gradient close to 26.8% was observed. For a fixed coverage ratio and slope gradient, the cumulative runoff volume increased with the rainfall intensity. Overland flow varied with the coverage ratio and this can be attributed to increases in the cumulative runoff volume and runoff velocity with increasing coverage ratio. The experimental results show that for double-ridge cultivation with film mulching, the best coverage ratio is 50:150. This ratio not only reduces moisture evaporation and promotes soil conservation, but also effectively improves rainwater utilization and reduces soil erosion. In addition, for slope gradients exceeding 26.8%, runoff decreases and the soil infiltration capacity increases, so a slope gradient of 26.836.4% is optimal for the local cultivation model.

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Review, impact of land use/cover change on soil erosion in the Lake Tana Basin, Upper Blue Nile, Ethiopia

Applied Water Science ◽

10.1007/s13201-020-01325-w ◽

2020 ◽

Vol 10 (12) ◽

Author(s):

Alemsha Bogale

Keyword(s):

Soil Erosion ◽

Overland Flow ◽

Agricultural Land ◽

Base Flow ◽

Nile River ◽

Cultivated Land ◽

Infiltration Capacity ◽

Lake Tana ◽

Blue Nile ◽

Lake Tana Basin

AbstractLake Tana Basin is located in upper Blue Nile Basin which is comprises a total area of 15,096 km2 of which 3063 km2 is covered by the Lake which is the source of Blue Nile river. Lake Tana Basin and Blue Nile River provide various benefits also for downstream countries. The basin is highly degraded by different natural and manmade problems and it influence both Ethiopia and downstream countries. The main cause of basin degradation is inappropriate LULC. Huge area of cultivated land using without suitable management is the major basin problem. It is due to insure food security coming from unprecedented population growth rate. Forested land has encouraged the infiltration capacity and permeability of the land. It helps to increase the recharge capacity contribute to base flow whereas it is vice versa for cultivated land which is quick overland flow and significant soil erosion have observed. Besides, the soil erosion from agricultural land is the main source of nutrient enters to the lake which is the cause for eutrophication. To combat such problems both up and downstream countries should discuss together and design and implement appropriate basin management strategies to sustain the biodiversity and hydrological system of the basin.

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A two-dimensional glacier–fjord coupled model applied to estimate submarine melt rates and front position changes of Hansbreen, Svalbard

Journal of Glaciology ◽

10.1017/jog.2018.61 ◽

2018 ◽

Vol 64 (247) ◽

pp. 745-758 ◽

Cited By ~ 2

Author(s):

E. DE ANDRÉS ◽

J. OTERO ◽

F. NAVARRO ◽

A. PROMIŃSKA ◽

J. LAPAZARAN ◽

...

Keyword(s):

Coupled Model ◽

Small Scale ◽

Two Dimensional ◽

Time Step ◽

Software Packages ◽

Front Position ◽

Circulation Patterns ◽

Glacier Front ◽

Order Of Magnitude ◽

Frontal Ablation

ABSTRACTWe have developed a two-dimensional coupled glacier–fjord model, which runs automatically using Elmer/Ice and MITgcm software packages, to investigate the magnitude of submarine melting along a vertical glacier front and its potential influence on glacier calving and front position changes. We apply this model to simulate the Hansbreen glacier–Hansbukta proglacial–fjord system, Southwestern Svalbard, during the summer of 2010. The limited size of this system allows us to resolve some of the small-scale processes occurring at the ice–ocean interface in the fjord model, using a 0.5 s time step and a 1 m grid resolution near the glacier front. We use a rich set of field data spanning the period April–August 2010 to constrain, calibrate and validate the model. We adjust circulation patterns in the fjord by tuning subglacial discharge inputs that best match observed temperature while maintaining a compromise with observed salinity, suggesting a convectively driven circulation in Hansbukta. The results of our model simulations suggest that both submarine melting and crevasse hydrofracturing exert important controls on seasonal frontal ablation, with submarine melting alone not being sufficient for reproducing the observed patterns of seasonal retreat. Both submarine melt and calving rates accumulated along the entire simulation period are of the same order of magnitude, ~100 m. The model results also indicate that changes in submarine melting lag meltwater production by 4–5 weeks, which suggests that it may take up to a month for meltwater to traverse the englacial and subglacial drainage network.

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The effect of rainfall intensity on soil erosion and particulate phosphorus transfer from arable soils

Water Science & Technology ◽

10.2166/wst.1999.0527 ◽

1999 ◽

Vol 39 (12) ◽

pp. 41-45 ◽

Cited By ~ 34

Author(s):

A. I. Fraser ◽

T. R. Harrod ◽

P. M. Haygarth

Keyword(s):

Soil Erosion ◽

Suspended Sediment ◽

Rainfall Intensity ◽

Overland Flow ◽

Agricultural Soils ◽

Arable Land ◽

Significant Proportion ◽

Particulate Phosphorus ◽

Arable Soils ◽

Flow Monitoring

Soil erosion, in the form of transported suspended sediment in overland flow, is often associated with high rates of particulate phosphorus (PP) (total P>0.45 μm) transfer from land to watercourses. Particulate P may provide a long-term source of P for aquatic biota. Twenty-two sites for winter overland flow monitoring were selected in south-west England within fields ranging from 0.2–3.8 ha on conventionally-managed arable land. Fields were situated on highly porous, light textured soils, lacking impermeable horizons and often overlying major aquifers. Long arable use and modern cultivation methods result in these soils capping under rain impact. Overland flow was observed when rainfall intensity approached the modest rate of 0.8 mm hr−1 on land at or near to field capacity. Low intensity rainfall (<2 mm hr−1) produced mean suspended sediment losses of 14 kg ha−1 hr−1, with associated PP transfer rates of 16 g ha−1 hr−1. In high intensity rainfall (>9 mm hr−1) mean PP losses of 319 g ha−1 hr−1 leaving the field were observed. As might be expected, there was a good relationship between PP and suspended sediment transfer in overland flow leaving the sites. The capacity of light soils to cap when in arable use, combined with heavy or prolonged rainfall, resulted in substantial discharges, soil erosion and associated PP transfer. Storms with heavy rain, typically of only a few hours duration, were characterised by considerable losses of PP. Such events, with return periods of once or twice a winter, may account for a significant proportion of total annual P transfer from agricultural soils under arable crops. However, contributions from less intense rain with much longer duration (around 100 hours per winter in many arable districts of the UK) are also demonstrated here.

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Impact of vegetative cover and slope on runoff, erosion, and water quality for field plots on a range of soil and spoil materials on central Queensland coal mines

Soil Research ◽

10.1071/sr99052 ◽

2000 ◽

Vol 38 (2) ◽

pp. 313 ◽

Cited By ~ 64

Author(s):

C. Carroll ◽

L. Merton ◽

P. Burger

Keyword(s):

Water Quality ◽

Soil Erosion ◽

Overland Flow ◽

Salt Content ◽

Vegetative Cover ◽

Rhodes Grass ◽

Erosion Rates ◽

Mine Sites ◽

The Impact ◽

Field Plots

In 1993, a field study commenced to determine the impact of vegetative cover and slope on runoff, erosion, and water quality at 3 open-cut coal mine sites. Runoff, sediment, and water quality were measured on 0.01-ha field plots from 3 slope gradients (10, 20, 30%), with pasture and tree treatments imposed on soil and spoil material, and 2 soil and spoil plots left bare. The greatest soil erosion occurred before pasture cover established, when a large surface area of soil (>0.5 plot area) was exposed to rainfall and overland flow. Once buffel grass (Cenchrus ciliaris) colonised soil plots, there were negligible differences in soil erosion between slope gradients. On spoil, Rhodes grass (Chloris gayana) reduced in situ soluble salt content, and reduced runoff electrical conductivity to levels measured in surrounding creeks. Where spoil crusted there was poor vegetative growth and unacceptably large runoff and erosion rates throughout the study.

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Small-scale spatio-temporal characteristics of accumulation rates in western Dronning Maud Land, Antarctica

Journal of Glaciology ◽

10.3189/002214308784886243 ◽

2008 ◽

Vol 54 (185) ◽

pp. 315-323 ◽

Cited By ~ 10

Author(s):

Helgard Anschütz ◽

Daniel Steinhage ◽

Olaf Eisen ◽

Hans Oerter ◽

Martin Horwath ◽

...

Keyword(s):

Accumulation Rate ◽

Temporal Variations ◽

Spatial Variations ◽

Small Scale ◽

Accumulation Rates ◽

Order Of Magnitude ◽

Dronning Maud Land ◽

Spatio Temporal ◽

Ground Penetrating ◽

Firn Core

AbstractSpatio-temporal variations of the recently determined accumulation rate are investigated using ground-penetrating radar (GPR) measurements and firn-core studies. The study area is located on Ritscherflya in western Dronning Maud Land, Antarctica, at an elevation range 1400–1560 m. Accumulation rates are derived from internal reflection horizons (IRHs), tracked with GPR, which are connected to a dated firn core. GPR-derived internal layer depths show small relief along a 22 km profile on an ice flowline. Average accumulation rates are about 190 kg m−2 a−1 (1980–2005) with spatial variability (1σ) of 5% along the GPR profile. The interannual variability obtained from four dated firn cores is one order of magnitude higher, showing 1σ standard deviations around 30%. Mean temporal variations of GPRderived accumulation rates are of the same magnitude or even higher than spatial variations. Temporal differences between 1980–90 and 1990–2005, obtained from two dated IRHs along the GPR profile, indicate temporally non-stationary processes, linked to spatial variations. Comparison with similarly obtained accumulation data from another coastal area in central Dronning Maud Land confirms this observation. Our results contribute to understanding spatio-temporal variations of the accumulation processes, necessary for the validation of satellite data (e.g. altimetry studies and gravity missions such as Gravity Recovery and Climate Experiment (GRACE)).

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Geo-informatics based Morphometric Analysis of a Reservoir Catchment in Shivalik Foothills of North-West India

Journal of Agricultural Engineering ◽

10.52151/jae2021581.1752 ◽

2021 ◽

Vol 58 (03) ◽

pp. 286-299

Author(s):

Mahesh Chand Singh ◽

Rohit Singh ◽

Abrar Yousuf ◽

Vishnu Prasad

Keyword(s):

Form Factor ◽

Soil Erosion ◽

Morphometric Analysis ◽

Overland Flow ◽

Infiltration Rate ◽

Elongation Ratio ◽

Alos Palsar ◽

Bifurcation Ratio ◽

Runoff Potential ◽

Drainage Texture

The present study examined 35 morphometric parameters related to stream/drainage network, catchment geometry, and relief aspects for hydrological characterization of the Thana Dam catchment using geospatial tools and techniques. The dam catchment was delineated using the high-resolution Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) Digital Elevation Model (DEM) data in ArcGIS 10.4.1 software using the Arc Hydro tools. The catchment is comprised of 4th order stream, obtained using a stream threshold value of 100 m length. The lower values of elongation ratio (0.61), circularity ratio (0.22), and form factor (0.29) indicated higher soil erosion potential, mainly due to their inverse relationship with land erodibility. Moreover, the higher values of stream frequency (15.7), drainage density (>5.0), drainage texture (7.48 km-1), and mean bifurcation ratio (4.08-6.33) indicated higher runoff potential, which would intensify the soil erosion, mainly due to their direct relationship with erodibility. Bifurcation ratio, elongation ratio, circulatory ratio, form factor, altogether indicated an elongated shape of the catchment with a fine drainage texture. The higher values of bifurcation ratio and texture ratio of the catchment also indicated severe overland flow (low infiltration rate) with a limited scope for groundwater recharge in the area, which in turn might significantly encourage the soil erosion. Overall, it was concluded that the catchment has a huge runoff potential resulting in high soil erosion due to its fine texture, impermeable subsurface material, steep slope, low infiltration rate, limited vegetation, longer duration of overland flow, and higher surface runoff. The morphometric analysis was found to be suitable for identifying catchment shape and the factors affecting hydrologic conditions and erodibility of the catchment. Thus, Geo-informatics based morphometric analysis of a reservoir catchment can be useful to study the erosion potential in relation to hydrologic (rainfall-runoff relationship) and other related land characteristics (e.g., relief, slope, infiltration rate, etc.).

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