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Recently, sand fences, made of high density polyethylene (HDPE) board, which is resistant against harsh plateau environmental conditions, could possibly be used to control the wind-blown sand along the Qinghai section of the Golmud-Korla Railway. In this paper, wind tunnel simulation was performed on the protective effect of multiple rows of HDPE board sand fences on wind-blown sand. Two parameters have been used to reflect the protective effect of sand fences, that is, windproof efficiency and sand control efficiency, referring to the reduction rates of wind speed at a height of 0.04 m and sand flux in a run of test with the fence compared those in the control run of test without it, respectively. The test results showed that when the porosity was 30%, the single-row sand fence had the best wind proof and sand control efficiency with respective values of 46% and 65.3%. The windproof efficiencies of double-row and triple-row sand fences at 20H were 59% and 62%, respectively. Compared with the windproof efficiency of the single-row sand fence, those of the two-row and three-row fences increased by 13% and 16%, respectively; The maximum sand control efficiency of the double-row and triple-row sand fences were 92.1% and 96.5%, increased by 26.8% and 31.2%, respectively, compared with that of the single-row sand fence. This study indicates that the sand control efficiency after adding one or two rows was not double or triple that of the single-row fence, while the first-row sand fence played a major protective role. Compared with the double-row sand fences, the effect of the third row sand fence in triple-row sand fences is limited, and thus double-row HDPE board sand fences with the porosity of 30% are recommended to control wind-blown sand along the Qinghai section of the Golmud-Korla Railway.

Based on the 3D fluid–solid coupling numerical calculation method, a systematic study was conducted on the bearing characteristics of a perforated sheet-type sand fence at a given penetration rate, opening size, and wind velocity. According to the results of this study, both the displacement and stress of the sand fence experienced an impact stage, a coupling stage, and a stabilization stage under different wind velocities and times. At the initial moment of the impact stage, both the displacement and stress of the sand fence reached their maximum, i.e., the maximum position of the sand fence displacement was at the top of the panel central line, whereas the maximum position of the stress was at the site of the column 4.5 cm away from the column bottom. The duration of the impact stage was 1.5 s and did not change with the opening size or wind velocity. In the coupling stage, the displacement and stress of the sand fence underwent intense fluctuations, and the amplitude of fluctuations decreased with time. The duration of the coupling stage did not change with opening size, but increased with the increase in wind velocity. In the stabilization stage, both the displacement and stress of the sand fence reached a stable state and did not significantly change with time. In each stage, both the displacement and stress of the sand fence are inversely proportional to the opening size and directly proportional to the wind velocity, i.e., the lower the opening size, the higher the wind velocity, and the greater the displacement and stress of the sand fence. However, when the hole diameter drops below 1.03 cm, it is no longer a main influencing factor of sand fence displacement or stress change. For the sand fence in each stage, the panel displacement was higher than the column displacement, whereas the column stress was higher than the panel stress. This paper provides a basis for the design and optimization of sand fence structures, lays the foundation for establishing a mechanics-physics model for the stress distribution of sand fence structures, and presents relatively high research values.

Landforms present in undeveloped beach enclaves located between properties developed with houses and infrastructure are often left to evolve naturally but are influenced by the human structures near them. This field study evaluates how buildings and sand-trapping fences change the direction of wind approach, reduce wind speed, and restrict fetch distances for sediment entrainment, thereby reducing the potential for aeolian transport and development of dunes in enclaves. Field data were gathered in an 80 m long, 44 m deep beach enclave on the ocean shoreline of New Jersey, USA. Comparison of wind characteristics in the enclave with a site unaffected by buildings revealed that offshore winds in the enclave are reduced in strength and altered in direction by landward houses, increasing the relative importance of longshore winds. Vertical arrays of anemometers on the foredune crest, foredune toe and berm crest in the enclave revealed increasing wind speed with distance offshore, with strongest winds on the berm crest. Vertical cylindrical traps on the foredune crest, foredune toe, mid-backshore, berm crest and upper foreshore revealed the greatest rate of sediment transport on the berm crest. Sediment samples from the beach and from traps revealed limited potential for aeolian transport because of coarse grain sizes. Strong oblique onshore winds are common in this region and are normally important for transporting sand to dunes. The length of an enclave and the setback distance on its landward side determine the degree to which sediment delivered by oblique winds contributes to dune growth. The landward edge of the enclave (defined by a sand fence near the dune toe) is sheltered along its entire length from winds blowing at an angle to the shoreline of 25° or less. A foredune set back this distance in an enclave the length of an individual lot (about 20 m) would be sheltered at an angle of 57° or less, reducing the opportunity for dune building by onshore winds. Reduced potential for aeolian transport in enclaves implies that human actions may be required to build dunes artificially to protect buildings and roads from storm overwash.

The inclined inserting-type sand fence is a novel sand retaining wall adopted along the Lanxin High-Speed Railway II in Xinjiang for controlling and blocking sand movement. To verify the effectiveness of the new fence structure for sand prevention, a wind tunnel test was used for flow field test simulation of the sand fence. The results indicate that the inclined inserting-type sand fence was able to deflect the flow of the sand and was able to easily form an upward slant acceleration zone on the leeward side of the sand fence. As shown by the percentage change in sand collection rates on the windward side and the leeward side of the sand fence, the sand flux per unit area at 4 m height in the slant upward direction increased on the leeward side of the inclined inserting-type sand fence. By comparing the flow fields, this site is an acceleration zone, which also reaffirms the correspondence of wind–sand flow fields with the spatial distribution characteristic of the wind-carried sand motion. The field sand collection data indicates that under the effects of the inclined inserting-type sand fence, the sandy air currents passing in front and behind the sand fence not only changed in quality, but the grain composition and particle size also significantly changed, suggesting that the inclined inserting-type sand fence has a sorting and filtering effect on the sandy air currents that passed through. The fence retained coarse particulates on the windward side and fine particulates within the shade of the wind on the leeward side.

A hanging-type sand-retaining wall is a very common sand-blocking fence structure used to prevent sand movement. This type of wall is widely used along the Qinghai–Tibet and Gobi desert railways in Xinjiang, Western China. To analyze the characteristics of wind-sand flow fields under the effect of such a sand fence structure, a wind tunnel test and a field test were carried out. The wind tunnel test showed the zoning characteristics of the flow fields under the effect of the hanging-type sand-retaining wall, and the field test provided the sediment transport data for effective wind-proof interval and the sand resistance data in the front and behind the sand-retaining wall. The consistency of the wind-sand flow fields with the spatial distribution characteristic of wind-carried sand motion was verified by the correspondences of the acceleration zone in the flow field and the negative elevation points of the percentage variations of the sand collection rate. The spatial distribution characteristic of the field sand collection data further showed the spatial structural characteristic of the sandy air currents under the action of the hanging-type sand-retaining wall and the sand resistance characteristic of the sand-retaining wall. This systematic study on the wind-sand flow fields under the control of the hanging-type sand-retaining wall provides a theoretical basis for the rational layout of sand control engineering systems and the efficient utilization of a hanging-type sand-retaining wall.

This study aimed to examine the effect of distance at three levels (5 m, 15 m, and 25 m) of ranges of plots landwards from a sand fence and bush hedge protection margin on the height growth and survival of seedlings of Pinus thunbergii Parl. planted in a coastal sandy environment in Uljin, East Sea area of Korea. The purpose of the study was to investigate height growth and survival with distance from a bush hedge/sand beach boundary of pine seedlings in a coastal forest plantation. Seedling height growth and survivorship were measured annually in nine plots, with three plots each selected from three ranges of plots at distances of 5 m, 15 m, and 25 m landward from the bush hedge/sand beach boundary from 2007 to 2014, 8 years after planting. Annual averages in seedling height growth significantly reduced in the 2nd and 3rd years of growth but appreciably stabilized from the 4th to 8th year, indicating that the 2nd and 3rd years of seedling growth and survival in the study site were the most critic...

Wind-blown sand disasters, as an environmental problem, have great impact on human activities. Sand fence has been recognized as an efficiency technology in anti-desertification engineering and is wildly applied to protect highways and railways around the desert. But few people study its protection to Gobi buildings, which may also suffer from sand disaster. To study its protection to Gobi buildings, we systemically investigate the three-dimensional structure of wind field and sand distribution around sand fence for buildings by Computational Fluid Dynamic simulations and wind-tunnel experiments. The dependencies of sand-prevention efficiency on fence height, porosity, inclined slat angle and wind speed are proposed respectively. An optimal height of sand fence is suggested to be 2.0 m−2.5 m, and an optimal porosity is 10%−15%, by synthetically considering the factors of sand prevention efficiency and construction cost; the slat angles of inclined fence is recommended as 135°−150° for maximizing the sand sedimentation on the windward side of fence.

Sand fences are widely used to control sand deposition to initiate or stabilize dunes. Previous studies on sand fences are often focused on the porosity control of their trapping efficiency, however, there exists very little research on the fence height effect. We deployed fences with three heights and equal porosity at a field site near Jericoacoara, Brazil, and examined the variation of their topographic profile and trapping efficiency. We identified two stages of dune development around fences. During stage I, dune topographic profile area is proportional to the fence and dune height, and the trapping efficiency decreases substantially with time. During stage II, dunes continue to grow horizontally and the trapping efficiency decreases with time, but at a slower rate compared to stage I. Coarser sand tends to deposit close to the fence. The findings from this study can enhance the understanding of the complex wind-sand-structure interactions and provide insights for future dune recovery applications.

Sand fences are a frequently used management tool on developed coastlines because they are inexpensive and easy to install. While the geomorphic effect of sand fences has been investigated before, previous studies have been limited in both temporal and spatial domains. Here, we present the evolution of Bogue Banks, a developed barrier island along the Outer Banks of North Carolina, over a 20-year period from 1997 to 2016 where sand fences were emplaced along parts of the island in 2010. We use LiDAR-derived cross-shore transects (n = 38,454) to measure beach and foredune features along the extent (~40 km) of Bogue Banks for every available year of lidar data as well as the locations of sand fences, which we identify in 39% of the transects following fence construction. First, we found that vertical growth of the natural foredunes along Bogue Banks was slightly positive between 2010 and 2016 despite an increased amount of shoreline erosion. This pattern was coincident with a combination of sand fence installation and beach nourishment efforts, which were most heavily focused on the eastern end of the island. Second, we found that natural foredunes located behind fenced dunes are typically shorter, wider, and smaller in volume than natural foredunes in non-fenced and undeveloped areas. Although this may partly be due to a tendency for fences to be installed in front of more vulnerable dunes, our results suggest that, once emplaced, sand fences prevent growth of the landward foredune behind fenced dunes. These findings suggest that sand fences block sediment supply to landward dunes, leading to a shorter and wider complex foredune than would otherwise naturally occur.

Coastal dunes represent a natural barrier and play a vital role in the coastal defense against the waves and tides. Dune enhancement or reconstruction is considered to be a solution to avoid the negative effects on the ecological and aesthetic values of the coast by those engineering structures. Two field experiments were conducted for dune building at the Tainan coast in Taiwan. Experimental sets, including artificial vegetation, sand fence deployment and the bulldozed dunes with different surface pavements, were set up to re-build the foredune that have been previously damaged. A small natural remnant dune was chosen as the comparison set for evaluating the effectiveness of the sand accumulation and vegetation growth. The dune reconstruction processes were observed by monitoring the changes of dune profiles, surface sand grain size, and the vegetation density. The experiment results are used to suggest an appropriate dune rehabilitation procedure for this area. The results reveal that a bulldozed dune can raise the height immediately, and putting oyster racks on the bare surface can help the accumulation of sand and the colonization of vegetation that will quickly stabilize the artificial foredune. Sand surface covered with oyster shells may avoid wind erosion at the beginning, but it also hampered the vegetation colonization. Muddy sand surface formed a hard crust to reduce the wind erosion, but it also hindered the infiltration process that two gullies were found on the dune after a heavy rain. Sand fence should have an appropriate fence porosity to be effective.

In semi-arid and arid regions, civil engineers may be required to plan measures, such as sand fences, to control sand movement affecting developed areas or transportation corridors. In this paper, considering the desertification process for the Minqin Oasis in Gansu Province, China, the design of sand fences and overall sand control strategies to lessen the rate of desertification are discussed. A sand transport model called MOSAND was developed to predict the sand transport rate for the Minqin Oasis. The model was based on a bed load transport (creep and saltation) equation and a logarithmic velocity profile for the wind. Using the measured wind data for the Minqin area, a monthly average sand transport rate was calculated that was used to determine an effective life span of a 3 m high sand fence. Sand fences in conjunction with straw checkerboard sand barriers are recommended to control sand drifts into the Minqin Oasis.

Sand-trapping fences modify the character of the coastal landscape and change its spatial structure, image, and meaning. This paper examines the relationship between these changes and fence usage at the municipal level, where most decisions about fence deployment are made. Use of fences in 29 municipalities on the developed coast of New Jersey is examined over a 6-year period. Interviews with municipal officers indicate that wooden slat sand-trapping fences are used primarily to build dunes to provide protection against wave uprush and flooding, but they are also used to control pedestrian traffic and demarcate territory. These uses result in changes in landforms and habitats. An aerial video inventory of fences taken in 2002 indicates that 82% of the shoreline had fences and 72% had dunes. Single and double straight fence rows are the most commonly used. Fences are often built to accomplish a specific primary purpose, but they can cause many different and often unanticipated changes to the landscape. The effects of a sand fence change through time as the initial structure traps sand, creates a dune that is colonized by vegetation, and becomes integrated into the environment by increasing topographic variability and aesthetic and habitat value. Sand fences can be made more compatible with natural processes by not placing them in locations where sources of wind blown sand are restricted or in unnatural shore perpendicular orientations. Symbolic fences are less expensive, are easy to replace when damaged, are less visually intrusive, and can be used for controlling pedestrian access.

Two effectiveness indices are proposed in this paper for evaluating dune recovery techniques: nourishment effectiveness (Ne) and sand fence effectiveness (Fe). Both indices were designed to be applied during monitoring programmes and were tested for Cacela Peninsula, Portugal. On this peninsula, a total volume of 480,000 m3 of sediments were dredged from the inner backbarrier channel and used for replenishment during the winter of 1996/1997. A 32% loss of material to the sea occurred due to superficial drainage during the spreading process. During the subsequent 25 months, 33% of the deposited material was eroded (50% due to wave action, 45% related to inlet displacement and 5% to lagoon processes). The determined nourishment life-time, based on monitoring data, was about 11 to 15 years, as compared to the designed life-time of 15 to 20 years. These values could be used as a guide for other re-nourishment projects. The value for the nourishment effectiveness index (Ne) obtained was about 75% to 76%, which corresponds to a reasonably effective protective scheme for this coastal dune. A set of fences was also installed and were effective sand traps in areas where the seaward nourishment bluff was small or absent. The sand fence effectiveness index (Fe) gave values increasing eastwards from 6% to 77%, corresponding to the longshore accumulation gradient related to the bluff height. This demonstrates that sand trap efficiency is very small when they are erected on top of obstacles (natural or artificial) to aeolian transport. For adequate dune recovery, in which the morphological, sedimentary and ecological characteristics are maintained, a combination of dune and upper beach nourishment and sand fencing is recommended. The effectiveness indices proposed here have the potential to be useful management tools but their use must be validated with the analysis of other monitored dune recovery cases.

Topography and vegetation of restored dunes on a developed barrier island were examined after a large-scale beach nourishment project. Restoration began in 1993 using sand-trapping fences andAmmophila breviligulata Fern. plantings. Subsequent growth of dunes was favored by installing new fences and suspending beach raking to accommodate nesting birds. Plant species richness, percent cover of vegetation, and height ofA. breviligulata were sampled in 1999 on seven shore perpendicular transects in six dune microhabitats (backdune, primary crest, mid-foredune, swale, seaward-most fenced ridge, incipient dune on the backbeach).

A numerical study of the turbulent air flow in a trench trap and the turbulent flow around a permeable sand fence is reported in this paper. The two-dimensional modified k-e turbulence model proposed by Kato and Launder is used to predict the turbulent characteristics of the air flow. The discretization method for the governing equations is the three-step Taylor/Galerkin finite element method proposed by the authors. For the flow in a trench trap the numerical results are compared with experimental data obtained under realistic conditions using a large wind tunnel. For the air flow around a permeable sand fence a pressure loss model is used to represent the effect of the porosity of the fence on the flow field.

Besides sandstorm, wind erosion and desertification, the deflation, transport and sediment of sand (dust) materials initiated by wind also lead to abrasion to structures, destruction to crops, and burying to roads and railroads, and so on. So the key of sand prevention is to lower the wind velocity in order to cut down the intensity of wind-blown sand flux and to increase the consolidated soil surface crusts so as to decrease the sand concentration in the air. The techniques of anti-desertification engineering could be classified into two categories, mechanical techniques and biological techniques. The former mainly include sand fence, straw checkerboard barrier and sand fixation by chemical adhesive. All of these techniques are designed to fix, block, or help transporting the sand flux. The latter mainly include establishing man-made plantations, recovering natural vegetation and building the protection forest so as to fix sand dunes and protect oasis.

Coastal dunes and wetlands are dynamic ecosystems that exist at the interface between land and sea. The coastal environment is harsh. Dunes are buffeted by wind, salt spray, sandblast, and temperature extremes. Tidal wetlands are exposed to wave action, inundation that promotes soil anoxia, and salinity. Also, soils of dunes and tidal wetlands are low in nitrogen which limits plant growth. Dunes depend on a supply of sand, carried off the beach by onshore winds, and vegetation to catch the sand. Dune restoration involves placing a sand fence, woody brush, or some other obstacle to catch the sand initially, and vegetation to stabilize it. In the foredune zone, where sand actively accumulates, beach grass (Ammophila sp.) and other species are planted to trap sand and hold it in place. Over time, the dune grows in size and woody vegetation colonizes the rear dune and initiates soil formation. Restoration of tidal marshes and mangroves usually involves planting vegetation, often Spartina spp., in the appropriate hydroperiod and salinity regimes, and time for vegetation to spread and cover the site. Restoration of wetland-dependent functions depends on accumulation of sufficient soil organic matter to support biogeochemical processes and food webs which takes about 5–15 years.

Sand dunes can provide an effective barrier to coastal flooding and wave damage. High, continuous dunes protect against flooding. Dunes containing large volumes of sand protect against wave damage by contributing their sand to the littoral stream during periods of high water and large waves. The level of protection is thus related to the height and volume of the dune. Coastal dunes evolve naturally as vegetation grows and flourishes on the backbeach. Dune growth is also induced by the erection of sand fencing. When the level of protection is reduced by coastal storms, the backbeach area becomes vulnerable to damage by subsequent storms until the dune is rebuilt, either naturally or by man's intervention. Thus there is a need to be able to predict rates of dune growth in order to estimate their recovery following a storm. The rate of sand dune growth at the Wildwood Convention and Civic Center (WCCC) was predicted using historical wind data (wind rose) and the median sand diameter. The predicted values were judged to be too high and were subsequently adjusted downward based on a comparison of the beach sand size distributions with the dune sand distribution and on dune growth rates observed elsewhere. A dune monitoring program was established to measure growth rates as well as the evolution of plants growing on the dunes. Measured dune growth rates during the first 1½ years following dune planting and sand fence erection were close to the predicted rates for each of three dune reaches. In the following years, dune growth slowed, presumably since much of the sand fence was buried. Later, dune volume was augmented by sand excavated from the construction site. An improved model using hourly offshore wind data was subsequently used. This model gave a good prediction of the rate of dune growth rate as well as an estimate of the dune sand size distribution.

To evaluate the sand volume blown from the beach to the inland, a field study was carded out using a sand fence installed at the inland side edge of beach. Field data showed that I) the sand volume accumulated around 2 m high fence was about 30 m 3 / m which was about half of that estimated assuming a dry sand surface condition, 2) the vertical distribution of the sand transport rate on the beach surface obeyed a predictive formula below a height of about 50 cm, 3) it is possible to control the wind-blown sand by employing suitable fencing works.

Frontal dunes are beach natural defenses against the rise of coastal waters and waves during storm surges, promoting a sand storage for beach restoration when erosion problems occurs. The management of coastal areas must include the protection of the existing dunes and the reclaiming of the disturbed ones. The employment of a simple device method in the stabilization of frontal dunes were tested in a pilot area (1 km long of beach line) in Osório county (RS, Brazil). The most effective system employed were simple fences parallel to the coastline and transverse fences to the dominant winds. The material used In the manufacture of these tracks, was dry grass of junco and tiririca plants tied to bamboo's sticks, according D regional workmanship's method. The most favorable year period to the management begins in spring, when strongs winds from NE quadrant increase in frequency and velocity. Meanwhile the more expressive sedimentation rate in the dunes occurs between December and February when the sand supply to the beach is larger. transported through waves of normal incidence and lower energy. This discussed method could be applied in other dune management projects along the Rio Grande do Sul coastline.

In order to prepare general guidelines for controlling the wind-blown sand in the region from the shoreline to the landward end of the dry beach, a literature review was carried out. The review showed that controlling wind-blown sand on a beach surface can be done by using a suitable combination and arrangement of sand fences and trenches.

Frontal dunes are beach natural defenses against the rise of coastal waters and waves during storm surges, promoting a sand storage for beach restoration when erosion problems occurs. The management of coastal areas must include the protection of the existing dunes and the reclaiming of the disturbed ones. The employment of a simple device method in the stabilization of frontal dunes were tested in a pilot area (1 km long of beach line) in Osório county (RS, Brazil). The most effective system employed were simple fences parallel to the coastline and transverse fences to the dominant winds. The material used In the manufacture of these tracks, was dry grass of junco and tiririca plants tied to bamboo's sticks, according D regional workmanship's method. The most favorable year period to the management begins in spring, when strongs winds from NE quadrant increase in frequency and velocity. Meanwhile the more expressive sedimentation rate in the dunes occurs between December and February when the sand supply to the beach is larger. transported through waves of normal incidence and lower energy. This discussed method could be applied in other dune management projects along the Rio Grande do Sul coastline.

Wind blown sand in inhabited arid regions is a serious environmental problem. Some of the problems are encroachment of drifting sand on roadways, railway tracks, farms and other essential installations. One of the most effective methods for controlling sand drift is using porous fences. In this paper some results of porous fence tests conducted in the Jafurah sand sea in Saudi Arabia are presented. The field tests involved a snow type fence, date palm leaf fence and an innovative spire-shaped elemental fence called the Jet fence. The Jet fence, whose porosity increases with height, proved to be the most efficient. The optimal porosity of the snow type fence as a sand fence was found to be about 50%.