Flow Interception Research Articles

Experimental and numerical investigation of debris flow interception using multiple stepped flexible barriers

Flexible barriers are a type of environmentally friendly and easily constructed retaining structure. Owing to the deformability and limited strength of the flexible barrier material, these barriers can only be used in small- or medium-sized debris-flow gullies. In this study, we proposed an improved layout, namely the multiple stepped flexible barriers, to address the limitations of traditional flexible barriers in the application of debris-flow control. We used experimental and numerical methods to investigate the separation effect of the multiple stepped flexible barriers and their stress and strain distributions in solid aggradation after reaching its maximum storage capacity. The results demonstrated that the ability of the multiple stepped flexible barriers to separate large particles gradually decreases with increasing debris-flow density, which implies that the debris-flow regulation ability of the multiple stepped flexible barriers decreases with increasing debris-flow density. When the debris-flow density exceeds 2200 kg/m3, the multiple stepped flexible barriers will completely lose their ability to reduce the density of debris flows. In addition, the thickness of the solid aggradation initially increases and then subsequently decreases upstream; the thickness of the solid aggradation increases with increasing debris-flow density. The results obtained from numerical simulation demonstrated that there would be relatively large shear stress and shear strain near the bottom of each flexible barrier. When the longitudinal spacing of the flexible barriers increases to 1.6 times their height, the internal stress of the upper aggradation layer that was transferred to the lower layer gradually weakens or disappears. Under this condition, the soil pressure of the flexible barrier is relatively small. The results of this study provide guidance for the design and construction of multiple stepped flexible barriers in wide debris-flow gullies.

The storm runoff management strategy based on agricultural ditch nutrient loss characteristics in Erhai Lake, China

Initial flush management is an effective measure to control non-point source pollution (NPSP) in storm runoff. However, determining the parameter of the initial flush in different areas may pose challenges in storm runoff management strategies. To address this issue, Erhai Lake in China, Yunnan-Guizhou Plateau, was selected as an example for the study. Erhai Lake is a typical mesotrophic lake with the profound influence of NPSP. The NPSP control strategy in this area will provide a valuable reference for other lakes. In 2021, 289 storm events and 190 ditchwater samples were detected around Erhai Lake. The average flow in the ditches ranged from 0.004 to 0.147 m3/s, the instant total nitrogen (TN) concentration ranged from 0.28 to 91.43 mg/L, and the instant total phosphorus (TP) concentration ranged from 0.26 to 7.35 mg/L in the storm events. It was found that the concentration of pollutants was lower than expected in the initial flush period. Instead, the event mean concentrations of TN and TP were 9.3 and 2.1 times higher than in the wet seasons, showing high nutrient concentration levels throughout the entire rainfall period. To manage storm runoff effectively, a flow-processes-division method was proposed to analyze the inflow condition and pollutant removal rate in different runoff periods. The peak flow interception strategy was recommended as the optimal stormwater management plan, as it showed the highest inflow conditions and 50% pollutant removal rate.Considering the need to reduce the constant flush of stormwater runoff, it is essential to establish a healthy water cycle system to alleviate NPSP and raise the Erhai water level. The storm runoff management method can serve as a practical tool for lake areas that do not exhibit initial flush characteristics.

Aeolian sand cover affects the soil hydrothermal state and permafrost degradation on the Qinghai-Tibet Plateau

Aeolian sand significantly affects permafrost degradation, but the effect of the aeolian sand on the permafrost on the Qinghai-Tibet Plateau remains unknown. The sand layer thickness is critical to its role. However, little quantitative research has been conducted on the effect of the sand layer thickness on its role. In this study, using CoupModel, we investigated the differences in the impact of the aeolian sand cover on the hydrothermal state of permafrost with 20 different sand layer thicknesses (10 ∼ 200 cm, 10 cm increment) and analyzed the mechanisms that explain the different impacts. The results reveal that the active layer is where the aeolian sand has the most impact on the permafrost. The aeolian sand layer accumulates precipitation into the soil below the sand, thereby significantly drying the shallow soil layer of the current stratum. Moreover, the thicker the sand layer, the more water accumulates in the underlying soil layer. In the middle-upper active layer, the initial soil heat storage, soil heat flow interception, and liquid water and ice contents govern the soil temperatures that increase in cold seasons and decrease in warm seasons as the sand layer thickens. Near the bottom of the active layer, the initial soil heat storage and soil heat flow interception control the soil temperatures that increase in cold seasons but fluctuate between sand layer thicknesses of 50 cm, 70 cm, and 120 cm in warm seasons as the sand layer thickens. Permafrost degradation is enhanced by sand layers thinner than 150 cm and retarded by sand layers thicker than 150 cm, respectively. The thermal state, soil properties, and accumulation process of the aeolian sand also contribute to this effect of the aeolian sand on the permafrost. In the plateau aeolian deserts, the sparse vegetation promotes permafrost degradation and the thinner seasonal snow cover protects permafrost. Moreover, under the different climate during the geological history period, the island or discontinuous permafrost might be formed due to the pluvial-radiation talik caused by the thicker sand layer or dunes.

Curb pollution of river -dealing with dry weather flow interception

The Mithi River having length of 17.8 km runs through densely populated residential and industrial areas in Mumbai. Except during the monsoon, behaves as a non-perennial water body and carries only sewage during the rest of the year. The Mithi River has a catchment area of 7,295 ha and receives overflows from Vihar and Powai lakes at its origin of 246 m above mean sea level on the periphery of Sanjay Gandhi National Park. The Mithi River flows through densely populated residential and industrial areas, Marol, Andheri, Bail Bazar to meet the Arabian Sea at Mahim Bay. This has resulted into pollution of river water by joining of nallas with Dry Weather Flows. The methodology & flow of study work adopted i.e. data collection, Topographical surveys, measurement of DWF at ingress locations in the river and suggested the feasible solution i.e. Dry Weather Flow Interceptors, STP etc. Under this Study, Identified the 52 nos of DWF (Dry weather flow) outfalls into Mithi River for Area 1 of Mithi River (Filterpada to WSP site). It found that daily 24 MLD DWF is entered into the Mithi river form Filter Pada to WSP Site. This is damaging to the environment, public health and visual landscape of the river & polluted river. So it is necessary to stop ingress of DWF into river & give the suitable treatment before further flow into river. Under this studied in various measures in detail to Curb Pollution of Mithi River. Adequate Dry Weather Flow Interceptors (DWFI), Sewer Network, Sewage Treatment Plant are designed and proposed to treat the Dry Weather Flow for required standards.After implementation of these solutions good results will be achieved i.e. river will flow with treated water all time and get the river to its original natural conditions free from pollution.

Investigation on microscopic invasion characteristics and retention mechanism of fracturing fluid in fractured porous media

Reservoir damage caused by guar gum fracturing fluid and slick water seriously affects the subsequent oil and gas production. However, the invasion characteristics and retention mechanisms of fracturing fluids in the fracture-matrix zone are still unclear. In this work, a microscopic model reflecting the characteristics of the fracture-matrix zone was designed. Based on the microfluidic experimental method, the process of fracturing fluid invasion, flowback and retention in the fracture-matrix zone was investigated visually and characterized quantitatively. The factors and mechanisms affecting fracturing fluid retention in the fracture-matrix zone were analyzed and clarified. The results indicated that in the invasion process, the frontal swept range of slick water was larger than that of the guar gum fracturing fluid, and the oil displacement efficiency and damage rate were lower than those of the guar gum fracturing fluid under the same invasion pressure. With the increase in invasion pressure, the damage rate of slick water increased from 61.09% to 82.77%, and that of the guar gum fracturing fluid decreased from 93.45% to 83.36%. Before subsequent oil production, the invaded fracturing fluid was mainly concentrated in the medium-high permeability area of the fracture-matrix zone. The main resistance of slick water was capillary force, while that of the guar fracturing fluid was mainly viscous resistance. The fracturing fluid retention was most serious in the low permeability region and the region near the end of the fracture. The experimental and numerical simulation results showed that increasing the production pressure difference could improve the velocity field distribution of the fracture-matrix zone, increase the flowback swept range and finally reduce the retention rate of the fracture fluid. The retention mechanisms of slick water in the fracture-matrix zone include emulsion retention and flow field retention, while those of the guar gum fracturing fluid include viscous retention and flow field retention. Emulsion retention is caused by capillary force and flow interception effect. Viscous retention is caused by the viscous resistance of polymer, while flow-field retention is caused by uneven distribution of flowback velocity.

Soil and water conservation in terraced and non‐terraced cultivations: an extensive comparison of 50 vineyards

AbstractUnderstanding the soil and water conservation (SWC) impact of steep‐slope agricultural practices (e.g. terraces) has arguably never been more relevant than today, in the face of widespread intensifying rainfall conditions. In Italy, a diverse mosaic of terraced and non‐terraced cultivation systems have historically developed from local traditions and more recently from the introduction of machinery. Previous studies suggested that each type of vineyard configuration is characterised by a specific set of soil degradation patterns. However, an extensive analysis of SWC impacts by different vineyard configurations is missing, while this is crucial for providing robust guidelines for future‐proof viticulture. Here, we provide a unique extensive comparison of SWC in 50 vineyards, consisting of 10 sites of 5 distinct practices: slope‐wise cultivation (SC), contour cultivation (CC), contour terracing (CT), broad‐base terracing (BT) and oblique terracing (OT). A big‐data analysis approach of physical erosion modelling based on high‐resolution LiDAR data is performed, while four predefined SWC indicators are systematically analysed and statistically quantified. Regular contour terracing (CT) ranked best across all indicators, reflecting a good combination of flow interception and homogeneous distribution of runoff and sediment under intense rainfall conditions. The least SWC‐effective practices (SC, CC, and OT) were related to vineyards optimised for trafficability by access roads or uninterrupted inter‐row paths, which created high upstream‐downstream connectivity and are thus prone to flow accumulation. The novel large‐scale approach of this study offers a robust comparison of SWC impacts under intense rainstorms, which is becoming increasingly relevant for the sustainable future management of such landscapes.

The maximum expected flow interception problem in a competitive environment

The maximum expected flow interception problem in a competitive environment

The flow interception location model with congestion cost based on the number of facility users and its heuristic solution method

The flow interception location model with congestion cost based on the number of facility users and its heuristic solution method

Method and apparatus for removing orbital space debris from near earth orbit using the solar wind: Platform for redirecting and removing inert space material (PRRISM)

A Platform for Redirecting and Removing Inert Space Material (PRRISM) is a system utilizing an antenna generating an electromagnetic (EM) wave to interact with a solar EM wave to streamline magnetic flux in the Polar Cusp and to facilitate the flow of solar plasma through the Polar Cusp, resulting in an increased density, velocity, and pressure at the exit of the Polar Cusp. The elevated plasma flow intercepts and removes small space debris from Low Earth Orbit (LEO), Geosynchronous Earth Orbit (GEO) and Geosynchronous Transfer Orbits (GTO) transiting the LEO altitude regimes. Patent: US 10,501,212 B2, Dated: December 10, 2019

Mobile vehicle emission inspection service optimization: a flow intercepting location model and application

ABSTRACTEmission screening and control for motorized traffic is mandatory in most countries worldwide. However, there may be cases that periodic inspections in permanent establishments may be inefficient and fail to enforce emission regulations among moving vehicles. In such cases, authorities deploy mobile inspection units, which perform random vehicle emission screening. This is particularly necessary for incoming and through traffic of origins not within the jurisdiction of local authorities. This paper investigates the problem of efficiently designing such a mobile inspection service, under resource availability and space constraints. The problem is addressed as a flow interception location model, formulated as a non-linear – integer mathematical programming model and solved using a genetic algorithm. The model is demonstrated for the case of the city of Alexandroupoli and results are discussed.

Using ArcGIS hydrologic modeling and LiDAR digital elevation data to evaluate surface runoff interception performance of riparian vegetative filter strip buffers in central Iowa

The Midwest is well known for agriculture, and Iowa is a leader in corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) production. Fertilizers and chemical pesticides used to increase crop production can adversely affect the soil and water health. Midwest farmers also produce livestock and graze cattle on pastureland that can lead to excessive surface runoff and soil erosion. Establishing vegetative filter strips (VFSs) along the edge of farmland is one of the best management practices (BMPs) to reduce nutrient and sediment loss. However, studies have revealed that the classic VFS design along the length of an agricultural field does not adequately address nonuniform flow through the buffer. New designs are being researched to increase the efficiency of the VFS. In order to accurately implement new design strategies, the runoff flowpaths into the VFS need to be accurately modeled. This research assesses the performance of existing established VFS buffers of selected sites by modeling and analyzing the flow accumulation from the field into the VFS using geographic information system (GIS) and light detection and ranging (LiDAR) derived digital elevation model (DEM) 5 × 5 m data. This study also employed the new coefficient of flow interception (CFI) approach that improves the process of identifying areas where flow is concentrated and designing more efficient filter strips to account for concentrated runoff. In this study, the performance of VFS in three sites was evaluated by developing and using the CFI. Among the three sites, site 1 had very poor efficiency and no flow passes through the VFS, site 2 had low efficiency, and site 3 had excellent efficiency.

Infiltration Rate of Pervious Concrete on Street Curb Application

The street curb and stormwater inlets are among the component often found on the road which serve as part of the urban stormwater drainage system. They act as a stormwater removal and discharge it into the underground drainage system. However, the current stormwater inlet practiced in Malaysia has limitations which often cause water ponding and consequently lead to road flooding. Rather than improving the performance of stormwater inlet, the flow interception and rate of stormwater removal may be enhanced by introducing a new technology called the pervious curb. It isto be made of pervious concrete which provide an ability to allow water to pass through it.This paper attempts to adapt the existingtwo pervious concrete mix design and applied it into the so-called pervious curb. Herein, a newly designed infiltration rate test was used to test the pervious concrete performance under the effect of infiltration through side surface of the concrete curb. While doing so, the infiltration rate of the pervious concrete will be investigated under varying slopes. Results showed that the infiltration rate is quite high and the rate of infiltration increases as the inclination gutter increases. Thus, it is proven that the new infiltration rate test is applicable and can be used for other similar applications. Furthermore, the test has significantly revealed that the pervious concrete has high potential in enhancing flow interception and able to reduce water ponding as a street curb.

Anthropogenic disturbances of natural ecohydrological processes in the Matlabas mountain mire, South Africa

Matlabas is a mountain mire in Marakele National Park, located within the headwaters of the Limpopo River in South Africa. This mire consists of a complex of valley-bottom and seepage wetlands with small elevated peat domes. The occurrence of one decaying peat dome, which has burnt, and desiccated wetland areas with terrestrial vegetation has raised concerns. The aim of this study was to understand the mire features and water flows in order to identify the potential drivers causing wetland degradation. Wells and piezometers were installed to monitor the hydraulic head and collect water samples for analysis of ion composition, 18O and 2H stable isotope content, and δ13C and 14C isotope content for radiocarbon dating. Moreover, peat temperature profiles were measured and peat deposits were also dated using radiocarbon. Results indicate that the Matlabas mire developed in the lowest central-east side of the valley by paludification at the onset of the Holocene. During the Mid-Holocene, peat development was extended laterally by autogenic and allogenic processes. Three types of water flows driving peat development were identified – sheet flow, phreatic groundwater flow and deep groundwater flow – two of which are surface or near surface flows. The recent occurrence of decaying peat domes and desiccated wetland areas is possibly related to loss of exfiltrating deep groundwater flows that have resulted from drainage by the head-cut channels in the mire and interception of near surface water flow by an access road, respectively. Interventions should be undertaken to prevent further degradation of the mire.
 Significance:
 
 This study is the first, as far as we are aware, on the ecohydrology of an inland mountainous mire in southern Africa.
 The results highlight the importance of the current wetland management (including rehabilitation) initiatives in South Africa.
 The integrative ecohydrological methods can be applied in other headwater wetlands in southern Africa.

The Probabilistic Minisum Flow Interception Problem: Minimizing the Expected Travel Distance until Intercept under Probabilistic Interception

We develop a variant of the flow interception problem (FIP) in which it is more desirable for travelers to be intercepted as early as possible in their trips. In addition, we consider flows being intercepted probabilistically instead of the deterministic view of coverage assumed in the FIP literature. We call the proposed model the probabilistic minisum FIP (PMFIP); it involves minimizing the sum of the expected distance that each flow travels until intercepted at a facility among placed facilities. This extension allows us to evaluate the effect of facility location under any given value of the interception probability and to apply the model to a variety of situations. We apply the proposed model to an example network by assuming a hypothetical situation in which people gather at a stadium from various nodes on the network, and receive some goods or services on the way to the stadium. We analyze optimal solutions obtained by varying the number of facilities and interception probability. It is shown that the expected travel distance until intercept is greatly reduced by means of a few optimally located facilities under a moderate interception probability.

Evaluating Curb Inlet Efficiency for Urban Drainage and Road Bioretention Facilities

An updated two-dimensional flow simulation program, FullSWOF-ZG, which fully (Full) solves shallow water (SW) equations for overland flow (OF) and includes submodules modeling infiltration by zones (Z) and flow interception by grate-inlet (G), was tested with 20 locally depressed curb inlets to validate the inlet efficiency (Eci), and with 80 undepressed curb inlets to validate the inlet lengths (LT) for 100% interception. Previous curb inlet equations were based on certain theoretical approximations and limited experimental data. In this study, 1000 road-curb inlet modeling cases from the combinations of 10 longitudinal slopes (S0, 0.1–1%), 10 cross slopes (Sx, 1.5–6%), and 10 upstream inflows (Qin, 6–24 L/s) were established and modeled to determine LT. The second 1000 modeling cases with the same 10 S0 and 10 Sx and 10 curb inlet lengths (Lci, 0.15–1.5 m) were established to determine Eci. The LT and Eci regression equations were developed as a function of input parameters (S0, Sx, and Qin) and Lci/LT with the multiple linear regression method, respectively. Newly developed regression equations were applied to 10,000 inlet design cases (10 S0, 10 Sx, 10 Qin, and 10 Lci combinations) and comprehensively compared with three equations in previous studies. The 100% intercepted gutter flow (Qg100) equations were derived, and over-prediction of Qg100 from previous methods was strongly correlated to smaller S0. Newly developed equations gave more accurate estimations of LT and Eci over a wide range of input parameters. These equations can be applied to designing urban drainage and road bioretention facilities, since they were developed using a large number of simulation runs with diverse input parameters, but previous methods often overpredict the gutter flow of total interception when the longitudinal slope S0 is small.

Supercritical Stormwater Flow Interception through Bottom Rack with Transverse Barrier

AbstractThe Hong Kong West Drainage Tunnel (HKWDT) system consists of 34 stormwater intake structures designed to intercept stormwater runoff in upland catchments. During stormwater events, each of...

Hydrological indicators of flow in headwaters for assessing farm management impacts: Streamside forestry management case study

Hydrological indicators have been used for interpreting stream flow patterns in large catchments. It would be useful to evaluate such indicators for use also in headwater catchments close to the source of on-farm management impacts. Reforestation of cleared farmland is encouraged internationally for water quality and biodiversity improvements. One practice option is to establish fast-growing plantations in streamside management zones (SMZs), but impacts on stream flows are not well understood. A eucalypt plantation was established in a steep headwater catchment in temperate Australia and stream flows compared 2 years pre- and 4 years post-establishment with an adjacent unplanted catchment. The flow ratio of SMZ to control was never significantly different from one (no SMZ effect) despite a significant decreasing trend during the six-years of monitoring. The decrease in flow ratio was attributable mainly to a reduction in some higher flows resulting from increased surface roughness and interception of overland flow. Nonparametric analyses also indicated a reduction of some low flows due to plantation establishment. Overall, changes in flow patterns appeared minor, but the value placed on such changes will depend on social and environmental contexts. Because of the rarity of such data and the importance of understanding water flows as affected by plantations established on farmland, similar studies should be conducted elsewhere. The range of flow indicators tested in this case were useful and should be considered for other similar applications. In addition, a simulation capability needs to be developed to enable the effects of SMZ plantations on stream flows to be predicted for a range of climate, landscape and management contexts and to contribute further to policy and practice discussions.

Railway flow interception location model: Model development and case study of Tokyo metropolitan railway network

The flow interception location model (FILM) focuses on vehicular traffic in a road network and locates a fixed number of facilities so as to maximize the total flow that can be serviced at facilities along preplanned routes, such as a daily commute to work. This paper develops a version of FILM, the railway flow interception location model (R-FILM), that explicitly focuses on railway passenger flows. For railway users, accessing a facility placed at an origin, destination, or transfer station (ODT station) is easier than visiting a facility at other stations included in the travel path. Accessing a facility at a non-ODT station involves the additional cost of disembarking the train to obtain a service and then boarding another train after consuming the service. R-FILM introduces this railway-specific structure to FILM by introducing two different coverages according to the types of station intercepted for each flow. Concretely, a given flow is called strongly covered when at least one facility is located at an ODT station. Similarly, a given flow is called weakly covered when no facility is located at an ODT station, but at least one facility is located among stations included in the travel path. We present an integer programming formulation of the proposed R-FILM. Using it, we conduct a large-scale case study of the Tokyo metropolitan railway network, which includes about 1500 railway stations. Input flow is constructed using census data for commuter traffic, with about 100,000 distinct flow paths. Optimal solutions of both models for single- and multi-facility problems are analyzed. In R-FILM solutions, large terminal stations tend to be selected more often than with FILM.

X-Ray Quasi-periodic Oscillations in the Lense–Thirring Precession Model. I. Variability of Relativistic Continuum

Abstract We develop a Monte Carlo code to compute the Compton-scattered X-ray flux arising from a hot inner flow that undergoes Lense–Thirring precession. The hot flow intercepts seed photons from an outer truncated thin disk. A fraction of the Comptonized photons will illuminate the disk, and the reflected/reprocessed photons will contribute to the observed spectrum. The total spectrum, including disk thermal emission, hot flow Comptonization, and disk reflection, is modeled within the framework of general relativity, taking light bending and gravitational redshift into account. The simulations are performed in the context of the Lense–Thirring precession model for the low-frequency quasi-periodic oscillations, so the inner flow is assumed to precess, leading to periodic modulation of the emitted radiation. In this work, we concentrate on the energy-dependent X-ray variability of the model and, in particular, on the evolution of the variability during the spectral transition from hard to soft state, which is implemented by the decrease of the truncation radius of the outer disk toward the innermost stable circular orbit. In the hard state, where the Comptonizing flow is geometrically thick, the Comptonization is weakly variable with a fractional variability amplitude of ≤10%; in the soft state, where the Comptonizing flow is cooled down and thus becomes geometrically thin, the fractional variability of the Comptonization is highly variable, increasing with photon energy. The fractional variability of the reflection increases with energy, and the reflection emission for low spin is counterintuitively more variable than the one for high spin.

The geomorphic activity of forest roads and its dependencies in the Tatra Mountains

ABSTRACTForest roads in mountain areas have a significant impact on the changes of water circulation and cause the development of numerous erosion and accumulation forms. The aim of the study was to investigate the magnitude of geomorphic changes within forest roads, determine the factors influencing it, and assess the rate of erosion/accumulation within these roads. Geomorphological mapping of forest roads (6.2 km) was conducted. Roads were divided into homogeneous morphogenetic sections, and a set of parameters was measured for each of them. In order to determine the main factors responsible for relief changes within the roads, the Principal Component Analysis was used. The t-test for two independent samples was also used to check the influence of the bedrock type on the geomorphic changes within roads. Repeated cross-sectional profile measurements were conducted to determine the intensity of erosion and accumulation processes. Our results show that the magnitude of geomorphic changes within forest roads mostly depends on the presence of subsurface flow interception from the cutslope, which in most cases occurs when a road is constructed across a convergent slope area. The strength of the bedrock also has a significant impact on relief transformations, which is expressed in the higher amount of accumulation and erosion features, and higher dissection depths within weaker rocks. The highest annual rate of road deepening is 10 cm yr−1.