Sediment Trapping from Hyperconcentrated Flow as Affected by Grass Filter Strips

doi:10.1016/S1002-0160(13)60028-4

Pedosphere

Volume 23, Issue 3, June 2013, Pages 372-375

https://doi.org/10.1016/S1002-0160(13)60028-4 Get rights and content

Abstract

To evaluate the effect of vegetative filter strips on sediment trapping, the spatial distribution of deposited sediment, and the size distribution of deposited particles from hyperconcentrated flows, a simulated grass filter strip experiment was conducted with plastic grass using an adjustable slope steel flume. The simulated vegetation cover was 36%, and the inflow sediment concentrations applied were 147, 238, 320, and 429 kg m⁻³. The sediment concentration in the outflow, and the sediment particle size were determined. The results showed that the grass filter strips trapped most of the sediment from inflow at low sediment concentration. The deposition efficiency decreased with increasing sediment concentration, being 55.2% and 15.7% in the 147 and 429 kg m⁻³ sediment treatments, respectively. Most of the deposited sediments were distributed in the upper flume. In addition, the grass filter strips mainly trapped the coarse sediment (particle size > 10 μm).

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Cited by (14)

Experiments on measuring and verifying sediment trapping capacity of grass strips
2020, Catena
Citation Excerpt :
Hence, the study of vegetation sediment trapping is also very helpful in explaining the hillslope water quality process. The sediment trapping function of grass strips can be affected by many factors, such as slope, the flow rate and sediment concentration of silt-laden inflow, the silt particle size composition, and vegetation type and density, etc. (Saleh et al., 2018; Zhou et al., 2013). As for the influence of the slope, there is a consensus that the steeper the vegetation hillslope, the worse the sediment trapping effect (Mekonnen et al., 2015).
Vegetation-restored hillslopes not only reduce erosion but also trap sediment from uphill silt-laden inflow. To investigate the sediment trapping mechanism of grass strips, a series of crossed experiments with various factors, including slope (5–20°), sediment concentration (40–160 g L⁻¹), and unit flow rate (7.5–45.0 L min⁻¹ m⁻¹) were conducted using a 10-m-long and slope adjustable soil plot. The duration of each experiment was longer than required time to reach the stable state of sediment trapping, which ensures that the whole process of sediment trapping can be monitored and the maximum sediment trapping yield (sediment trapping capacity, R_m) can be obtained. The results showed that gentler slopes generated higher instantaneous sediment trapping efficiency (ISTE) and greater R_m. Higher sediment concentration or larger unit flow rate led to lower ISTE but greater R_m. The impact of slope on R_m amplified when the sediment concentration increased, implying that the interaction among these factors affects sediment trapping process. The sediment trapping effect of the first 2-m width grass strips performed better than the subsequent strips. 90% of sediment deposition occurred within first half of the time needed to reach the stable state. Slope had similar effect intensity on sediment trapping in each section of grass strips, so did flow rate, whereas the effect of sediment concentration was concentrated primarily in the first 5-m width. The standard regression coefficients of the multiple curve regression equation showed that the intensities of the impacting factors on R_m were as follows: slope > grass strips width > unit flow rate > sediment concentration. It indicated that slope plays a key role in controlling R_m. These results are helpful in assessing the effects of vegetation restoration on sediment transport at a hillslope scale.
Modeling study on the time-varying process of sediment trapping in vegetative filter strips
2020, Science of the Total Environment
Citation Excerpt :
Pan et al. (2011) proposed the hypothesis that ISTE is positively proportional to the difference between sediment trapping capacity and deposited sediment during runoff, and that ISTE decreases exponentially with time until near zero. Zhou et al. (2013) indicated that ISTE reaches zero faster under the condition of greater sediment concentration. All the above studies found that the ISTE of a VFS follows a time-decreasing function.
Vegetative filter strips (VFS) play an important role in reducing erosion, retaining runoff, and trapping sediment. The bed surface of a VFS is dynamic during continuous sediment deposition, which makes it difficult to determine the sediment transport capacity of overland flow in real time. This study described this process from a systematic perspective. Based on self-feedback theory, an ordinary differential equation was established with a self-inhibition correction factor and its analytical solution was obtained. A sediment-trapping-process model of VFS (STPMOD-VFS) was proposed. Then, the sediment trapping processes of three experiments under different conditions were predicted using the STPMOD-VFS, and the prediction was considered highly satisfactory. The uncertainty estimation results showed the STPMOD-VFS had significant ‘equifinality’ performance. The sensitivity of different parameters of the STPMOD-VFS was found significantly different. The parameters related to the sediment delivery rate of silt-laden inflow and those that control the attenuation coefficients of the instantaneous sediment trapping efficiency of the VFS were sensitive, while those parameters that control the initial sediment outflow rate were less sensitive. Finally, an equation describing the sediment trapping process by a VFS under a dynamic sediment inflow rate was built and solved, and a general expression for the VFS sediment trapping time-varying process was given. The findings of this study could help in evaluation of sediment processes on grassed hillslopes.
Vetiver grass hedgerows significantly trap P but little N from sloping land: Evidenced from a 10-year field observation
2019, Agriculture, Ecosystems and Environment
Citation Excerpt :
The nutrient trapping efficiency of VGH is determined by the amount of soil nutrients that are trapped within hedgerows of vetiver grass as compared to baseline nutrient status. Zhou et al. (2013) reported that the deposition efficiency decreased with increases in sediment concentration. Trapped sediments varied from 0.62 kg m−3 (Deletic, 2005) to 100 kg m−3 (Jin and Romkens, 2001) with trapping efficiency that ranged between 15% and 99% respectively.
The removal of soil N and P nutrients from sloping land by water erosion can cause land degradation and surface water pollution if not prevented. Vetiver grass hedgerows (VGH) established across the slope could help in trapping and stocking nutrients but its long-term impacts on N and P have not been studied. A 10-year field experiment was conducted to i) determine the effectiveness of different spacing of VGH to trap N and P discharged from sloping land, and ii) clarify the underlying mechanisms causing differences in N and P stocks by the establishments of VGH. Treatments consist of three VGH established at 5 m (VGH_5m), 10 m (VGH_10m), 20 m (VGH_20m) intervals and a control (plot without VGH). Trapped sediment N, P and particle size distribution were determined. VGH significantly (p < 0.01) trapped P but little N when compared to control. P trapped under different spacing of VGH relative to control decreased in the following order: VGH_5m (0.84 kg m⁻²), VGH_10m (0.59 kg m⁻²) and VGH_20m (0.48 kg m⁻²), with the P trapped efficiencies of 62.7%, 44.0% and 35.8% respectively. Clay trapped were significantly (p < 0.05) higher in VGH_5m (1.30 kg m⁻²), VGH_10m (1.13 kg m⁻²) and VGH_20m (1.01 kg m⁻²) plots than control with clay trapped efficiencies of 55.1%, 48.3% and 43.0% respectively. Also, silt trapped were significantly (p < 0.05) higher in VGH_5m (0.99 kg m⁻²), VGH_10m (0.86 kg m⁻²) and VGH_20m (0.55 kg m⁻²) plots than control with silt trapped efficiencies of 28.4%, 24.7% and 15.9% respectively. P trapped efficiency by VGH was significantly (p < 0.01) positively correlated to silt + clay trapped efficiency indicating that clay + silt trapped by VGH can retain P. But there was no significant relationship between N trapped efficiency and silt + clay trapped efficiency due to high solubility of N. Increased maize yields were significantly positively related to N (r² = 0.96; p < 0.01), P (r² = 0.97; p < 0.01) and C (r² = 0.98; p < 0.01) trapped by VGH. Our results imply that VGH trapped fine soil particles (silt + clay particles) that retained P but could not retain significant amount of N. The establishment of VGH across the sloping land will significantly reduce nutrient loss within eroded agricultural landscape and consequently increase crop yields.
Plant basket hydraulic structures (PBHS) as a new river restoration measure
2018, Science of the Total Environment
Citation Excerpt :
Vegetative structures or vegetative sediment traps have already been used to modify hydromorphological conditions in rivers. There has been a significant amount of research performed at the plot scale (Morgan, 2007; Wyżga et al., 2013) and laboratory scale (Hämmerling et al., 2014) using real or simulated vegetation, but the field-scale records of water flow and sediment transport are relatively limited (Blanco-Canqui et al., 2004; Costigan and Gerken, 2016; Nones et al., 2017; Ribeiro et al., 2016; Zheng-Chao et al., 2013). The aim of this study was to verify the morphological and hydraulic consequences of PBHS introduction to a river channel.
River restoration has become increasingly attractive worldwide as it provides considerable benefits to the environment as well as to the economy. This study focuses on changes of hydromorphological conditions in a small lowland river recorded during an experiment carried out in the Flinta River, central Poland. The proposed solution was a pilot project of the construction of vegetative sediment traps (plant basket hydraulic structures - PBHS). A set of three PBSH was installed in the riverbed in one row and a range of hydraulic parameters were recorded over a period of three years (six measurement sessions). Changes of sediment grain size were analysed, and the amount and size of plant debris in the plant barriers were recorded. Plant debris accumulation influencing flow hydrodynamics was detected as a result of the installation of vegetative sediment traps. Moreover, various hydromorphological processes in the river were initiated. Additional simulations based on the detected processes showed that the proposed plant basket hydraulic structures can improve the hydromorphological status of the river.
A modeling approach to determining the relationship between vegetative filter strip design and sediment composition
2017, Agriculture, Ecosystems and Environment
Citation Excerpt :
Instead, the simulated data for each erosion event were used to develop the SCVFS model. Because the VFS efficiency depends on topography (Zhou et al., 2013), among other factors, nine hillslope configurations were simulated per site. Each hillslope was randomly generated to simulate a wide range of hillslope configurations, reducing any bias that could result if only one hillslope configuration was used.
Vegetative filter strips (VFS) are areas of either planted or indigenous established vegetation designed to improve the quality of surface runoff. They can be incorporated into pastures, grassed waterways, terraces, or cropland to remove sediment, nitrogen, or phosphorus from runoff. However, their trapping efficiencies depend mainly on the sediment characteristics. The finer soil particles pass through the filter more easily and have more surface area, accounting for most of the transported sediment-bound pollutants. Therefore, the objective of this study was to use a modeling approach to develop a Sediment Composition Vegetative Filter Strip (SCVFS) model to predict the clay, silt and sand trapping efficiencies of VFS based on a wide range of soil loss data from Central Chile. The physically based Water Erosion Prediction Project (WEPP) model was implemented using actual soil and climate data from Central Chile to generate a soil loss database for many VFS designs. More than 22,000 erosion events were generated with data from 28 sites. Three nonlinear relationships were developed between clay, silt and sand delivery and VFS length. The clay and silt models provided accurate estimates compared to WEPP for the calibration (R² = 0.80–0.87) and validation (R² = 0.73–0.80) sites. However, the sand estimates were not correlated to WEPP (R² = 0.00–0.18), as the model computes sand using the difference between the total predicted sediments (R² = 0.77–0.89) and the clay and silt estimates. Nevertheless, because most of the sediment-bound pollutants move with the finer sediments, this is not a modeling limitation. Compared to other physically based VFS models, the SCVFS model is remarkably easy to use because it only requires the characteristics of the sediment delivery when there is no filter, the rainfall erosivity and the hillslope and filter lengths. Additionally, it can be easily combined with many existing erosion models that provide daily soil loss estimates, making it a flexible VFS design tool. This study provides the detailed methodology to construct this model and discusses its advantages and limitations.
Characteristics of the Sediment Transport Process in Vegetation Hillslopes under Different Flow Rates
2023, Water (Switzerland)

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: Supported by the National Natural Science Foundation of China (No. 40901131) and the Fundamental Research Funds for the Central Universities of China (No. GK201103003).

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Sediment Trapping from Hyperconcentrated Flow as Affected by Grass Filter Strips

Abstract

J. Hydrol.

J. Hydrol.

J. Hydrol.

J. Hydrol.

Geomorphology.

Grass barrier and vegetative filter strip effectiveness in reducing runoff, sediment, nitrogen, and phosphorus loss

Soil Sci. Soc. Am. J.

Effectiveness of vegetative filter strips in retaining surface-applied swine manure constituents

T. ASAE.