scholarly journals Runoff on rooted trees

2019 ◽  
Vol 56 (4) ◽  
pp. 1065-1085
Author(s):  
Owen Dafydd Jones
Keyword(s):  
Phase Change ◽  
Critical Point ◽  
Overland Flow ◽  
Infiltration Rate ◽  
Rainfall Rate ◽  
Soil Infiltration ◽  
Subcritical Case ◽  
Total Runoff ◽  
Overland Runoff ◽  
Idealised Model

AbstractWe introduce an idealised model for overland flow generated by rain falling on a hillslope. Our prime motivation is to show how the coalescence of runoff streams promotes the total generation of runoff. We show that, for our model, as the rate of rainfall increases in relation to the soil infiltration rate there is a distinct phase change. For low rainfall (the subcritical case) only the bottom of the hillslope contributes to the total overland runoff, while for high rainfall (the supercritical case) the whole slope contributes and the total runoff increases dramatically. We identify the critical point at which the phase change occurs, and show how it depends on the degree of coalescence. When there is no stream coalescence the critical point occurs when the rainfall rate equals the average infiltration rate, but when we allow coalescence the critical point occurs when the rainfall rate is less than the average infiltration rate, and increasing the amount of coalescence increases the total expected runoff.

A hysteretic model for rainfall-runoff of a simplifed catchment 

2021 ◽  
Author(s):  
Denis Flynn ◽  
Warren Roche
Keyword(s):  
Overland Flow ◽  
Previous History ◽  
Infiltration Rate ◽  
Nonlinear Phenomenon ◽  
Hysteretic Model ◽  
Rainfall Runoff ◽  
Total Runoff ◽  
History Of ◽  
Preisach Operator ◽  
Rainfall Runoff Model

<div>The soil can be modelled as a porous medium in which the three phases of matter coexist and produce the emergent phenomenon of hysteresis.</div><div>Rate-independent hysteresis is a nonlinear phenomenon where the output depends not only on the current input but also the previous history of inputs to the system. In multiphase porous media such as soils, the hysteresis is in the relationship between the soil-moisture content, and the capillary pressure.</div><div>In this work, we develop a simplified hysteretic rainfall-runoff model consisting of the following subsystems that capture much of the physics of flow through a slab of soil:</div><div>1) A slab of soil where rainfall enters and if enough water is present in the soil, it will subsequently drain into the groundwater reservoir. This part of the model is represent by ODE with a Preisach operator.</div><div>2) A runoff component: If the rainfall exceeds the maximum infiltration rate of the soil, the excess will become surface runoff. This part of the model is represented by a series of two hysteretic reservoirs instead of the two linear reservoirs in the literature.</div><div>3) A ground water storage and outflow subsystem component: this is also modelled by a hysteretic reservoir. Finally, the outputs from the groundwater output and the overland flow are combined to give the total runoff. We will examine this model and compare it with non-hysteretic case both qualitatively and quantitively.</div>

scholarly journals Evaluating the Road-Bioretention Strip System from a Hydraulic Perspective—Case Studies

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1778 ◽  
Author(s):  
Xiaoning Li ◽  
Xing Fang ◽  
Yongwei Gong ◽  
Junqi Li ◽  
Jianlong Wang ◽  
...  
Keyword(s):  
Case Studies ◽  
Overland Flow ◽  
Flow Simulation ◽  
Soil Infiltration ◽  
Rainfall Events ◽  
Safety Hazard ◽  
The Road ◽  
Total Runoff ◽  
The Mean ◽  
Infiltration Parameters

The two-dimensional overland flow simulation program, FullSWOF_2D, was revised to include submodules of determining infiltration by zones (Z) and grate-inlet (G) drainage from a 2D surface to a 1D pipe flow. The updated program, FullSWOF-ZG, was used to evaluate the performance of a road-bioretention strip (RBS) system and explore/understand key parameters of continuous RBS design. The program was validated using eight pervious surfaces under simulated rainfall events and tested with 20 experimental cases of a locally depressed curb inlet. The mean difference of simulated interception efficiencies (36.6%–86.0%) and observed interception efficiencies (34.8%–84.0%) of the curb inlet was 3.5%, which proves the program predicts the curb-inlet interception efficiency accurately. The 20 road-only and 20 RBS modeling cases were designed and modeled using the FullSWOF-ZG program. These case studies have different road lengths, curb inlet lengths, longitudinal slopes, cross slopes, bioretention-overflow inlet heights, and bioretention soil infiltration parameters. Only 34.6%–48.4% of the total runoff volume is intercepted by the RBS’s curb inlet under heavy rainfall (250 mm/h) and the remaining part of the runoff flows downstream along the road, which may cause local inundation and become a safety hazard. The curb inlet becomes the bottleneck of the RBS system that could impede the runoff flowing into the bioretention strip for detention and infiltration to improve the stormwater quality.

scholarly journals INFLUÊNCIA DAS CARACTERÍSTICAS AMBIENTAIS E DOS INFLUÊNCIA DAS CARACTERÍSTICAS AMBIENTAIS E DOS ATRIBUTOS DO SOLO NA INFILTRAÇÃO DA ÁGUA EM ÁREA URBANAATRIBUTOS DO SOLO NA INFILTRAÇÃO DA ÁGUA EM ÁREA URBANA

2020 ◽  
Vol 38 (4) ◽  
pp. 1029-1038
Author(s):  
Jéssyca Stanieski de SOUZA ◽  
Isabel Kaufmann de ALMEIDA ◽  
Glauber Altrão CARVALHO ◽  
Teodorico ALVES SOBRINHO ◽  
Cláudia Gonçalves Vianna BACCHI
Keyword(s):  
Physical Properties ◽  
Overland Flow ◽  
Infiltration Rate ◽  
Soil Physical Properties ◽  
Capital City ◽  
Soil Infiltration ◽  
Environmental Characteristics ◽  
Mato Grosso ◽  
Flow Simulator ◽  
The Relationship

This study investigated the influence of the environmental characteristics and soil properties on the soil infiltration rate in urban permeable area. The experiments were conducted at nine sampling points located in the urban perimeter of Campo Grande, capital city of Mato Grosso do Sul State, in the Brazilian Midwest. The infiltration rates were determined using a portable integrated rainfall and overland flow simulator. Each experiment was repeated three times, and a total of twenty-seven plots were collected. At the same time, environmental characteristics and soil physical properties, that may affect infiltration rate, were also evaluated. The relationship between the infiltration rate, the environmental plot characteristics and the soil physical properties was verified using a linear correlation matrix.

Influence of soil treading on sediment and phosphorus losses in overland flow

Soil Research ◽  
2003 ◽  
Vol 41 (5) ◽  
pp. 949 ◽  
Author(s):  
R. W. McDowell ◽  
J. J. Drewry ◽  
R. J. Paton ◽  
P. L. Carey ◽  
R. M. Monaghan ◽  
...  
Keyword(s):  
Overland Flow ◽  
Infiltration Rate ◽  
Sediment Concentration ◽  
Soil Disturbance ◽  
P Fractions ◽  
Soil Infiltration ◽  
Cultivated Soil ◽  
Soil Sediment ◽  
Phosphorus Losses ◽  
Total P

This study investigated the effect of simulated cattle treading on soil infiltration rate (saturated hydraulic conductivity: Ksat) and macroporosity, and the consequent loss of sediment and phosphorus (P) via overland flow from a grassland and cultivated soil used for dairy farming in southern New Zealand. Treading decreased soil macroporosity and Ksat, and hence time to ponding, which increased the volume of overland flow. Mean suspended sediment concentration was greater in the cultivated treatments (0.076 g/L) compared with the grassland treatments (0.014 g/L). In the grassland soil, sediment and particulate P fractions in overland flow increased with treading due to increased soil disturbance and decreased protection from erosion by grass cover. In contrast, for the cultivated soil, sediment and P concentration and load decreased with increasing treading, due to greater ponding which decreased the erosive power of raindrop impact. Dissolved and particulate P fractions followed similar trends, although mean total P (mostly particulate P) was greater in cultivated treatments (1.07 mg/L) than the grassland treatments (0.64�mg/L). Relationships were generated between macroporosity and the loss of sediment and P, showing the wider application of macroporosity for environmental assessment than solely an agronomic measurement.

The Experiment Study on the Soil Infiltration Characteristics of Yumenkou Water Pumping Station Irrigation District of Regional Scale

2013 ◽  
Vol 316-317 ◽  
pp. 661-664 ◽  
Author(s):  
Lin Hu Yuan ◽  
Gui Sheng Fan
Keyword(s):  
Soil Structure ◽  
Soil Moisture Content ◽  
Regional Scale ◽  
Infiltration Rate ◽  
Irrigation District ◽  
Shanxi Province ◽  
Soil Infiltration ◽  
Volume Weight ◽  
Water Pumping ◽  
Weight Content

This paper is based on an item of key problem of agriculture of Shanxi province through field test and indoor test. Capability of soil infiltration and soil moisture content,soil volume-weight,content of soil organic matter,soil structure were measured.Infiltration content and infiltration rate reflect the capability of soil infiltration. Ten points of Yumenkou irriqated area located in Hejin, Jishan,Xinjiang were choosed,which can represent the soil feature of this area very well.The study of soil infiltration will give the scientific reason for the rational determining of field irrigation technique parameter.

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

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.).

scholarly journals Karakteristik Tanah Longsor di Daerah Aliran Sungai Tangka

2018 ◽  
pp. 203 ◽  
Author(s):  
Usman Arsyad ◽  
Roland Alexander Barkey ◽  
Wahyuni Wahyuni ◽  
Karla Kembongallo Matandung
Keyword(s):  
Infiltration Rate ◽  
Ground Movement ◽  
Soil Infiltration ◽  
Local Conditions ◽  
Soil Weathering ◽  
Sparse Vegetation ◽  
Open Land ◽  
Landslide Slope ◽  
Steep Slopes

Landslides occur as a result of ground movement on steep slopes, and the high humidity (moisture), and the sparse vegetation (open land). The Local conditions is an interrelated components. The process of landslides can be explained that the water soak into the soil will add weight to the ground. If the water penetrates the soil acts as a watertight sliding plane, the ground becomes slippery and soil weathering on it will move to follow the slope. This study aims to determine the type of landslide, landslide characteristics and landslides causing factors. This research was conducted in September 2015 in Watershed Tangka. The study consisted of three stages, namely the determination of the coordinates of the location of the landslide, landslide determining the location of the sample, the determination of the type of landslide, slope measurements, measurements of the dimensions of landslide and infiltration. Research results obtained are the coordinates of the location of as many as 17 points landslide, landslide types of translation and rotation, land cover and soil texture. There is no difference in the type of soil, infiltration rate, vegetation, geologi, slope and rainfall in both types of landslide are found. 

Implications of Phase Change on the Aerodynamics of Centrifugal Compressors for Supercritical Carbon Dioxide Applications

2020 ◽  
Author(s):  
Giacomo Persico ◽  
Lorenzo Toni ◽  
Paolo Gaetani ◽  
Ernani Fulvio Bellobuono ◽  
Alessandro Romei ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Power Systems ◽  
Phase Change ◽  
Critical Point ◽  
Fluid Dynamic ◽  
Flow Analysis ◽  
Design Strategy ◽  
Ideal Gas ◽  
New Challenges ◽  
Line Design

Abstract Closed Joule-Bryton cycles operating with carbon dioxide in supercritical conditions (sCO2) are nowadays collecting a significant scientific interest, due to their high potential efficiency, the compactness of their components, and the flexibility that makes them suitable to exploit diverse energy sources. However, the technical implementation of sCO2 power systems introduces new challenges related to the design and operation of the components. The compressor, in particular, operates in a thermodynamic condition close to the critical point, whereby the fluid exhibits significant non-ideal gas effects and is prone to phase change in the intake region of the machine. These new challenges require novel design concepts and strategies, as well as proper tools to achieve reliable predictions. In the present study, we consider an exemplary sCO2 power cycle with main compressor operating in proximity to the critical point, with an intake entropy level of the fluid lower than the critical value. In this condition, the phase change occurs as evaporation/flashing, thus resembling cavitation phenomena observed in liquid pumps, even though with specific issues associated to compressibility effects occurring in both the phases. The flow configuration is therefore highly nonconventional and demands the development of proper tools for fluid and flow modeling, which are instrumental for the compressor design. The paper discusses the modeling issues from the thermodynamic perspective and then highlighting the implications on the compressor aerodynamics. We propose tailored models to account for the effect of the phase change in 0D mean-line design tools as well as in fully 3D computational fluid-dynamic (CFD) simulations. In this way, a design strategy is build-up as a combination of mean-line tools, industrial design experience, and CFD for detailed flow analysis. The application of the design strategy reveals that the potential onset of the phase change might alter significantly the performance and operation of the compressor, both in design and in off-design conditions.

scholarly journals Effects of vegetation lodging on overland runoff flow regime and resistance

2020 ◽  
Vol 20 (4) ◽  
pp. 1463-1473
Author(s):  
Jingzhou Zhang ◽  
Shengtang Zhang ◽  
Guibao Li ◽  
Ming Liu ◽  
Si Chen
Keyword(s):  
Flow Regime ◽  
Water Depth ◽  
Overland Flow ◽  
Resistance Coefficient ◽  
Soil Consolidation ◽  
Slope Engineering ◽  
Overland Runoff ◽  
Flow Propagation ◽  
Water Depths ◽  
Fluid Characteristics

Abstract Vegetation is a vital part of the natural environment. Variations in vegetation morphology produce changes in the mechanical and fluid characteristics of overland flow. Determining the effects of vegetation lodging on the overland runoff flow regime and resistance is a prerequisite for accurately simulating overland runoff and convergence, revealing the mechanism of overland flow propagation, and the design and management of vegetation protection, soil consolidation, and ecological slope engineering. To systematically study the effects of vegetation lodging on overland runoff, four planting vegetation lodging angles (α) and 10 test water depths were used to simulate experimental research with a 1.0% slope ratio. Experimental results show that the depth and state of vegetation inundation and the degree of lodging significantly influence the flow regime and resistance. Under the same water depth, higher values of α are associated with higher values of the flow velocity, Reynolds number, Froude number, and Darcy–Weisbach resistance coefficient (f), and lower values of the drag coefficient (CD). The overall result is enhanced turbulence in the flow field and weaker flow resistance. Numerical statistics and difference analysis indicate that, when the vegetation is non-submerged, a 10° increase in α produces a 9.30% decrease in f. In the submerged state, a 10° increase in α causes a 26.70% decrease in f. CD is greatly affected by the boundary water depth. Below some critical water depths, an increase of 10° in α reduces CD by 8.48%. Above the critical depth, a 10° increase in α decreases CD by 41.10%.

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