International Journal of Sediment Research
Volume 32, Issue 2, Pages 137-294 (June 2017)
A probabilistic model for sediment entrainment: The role of bed irregularity
Pages 137-148
Mohamed Elhakeem, A.N. Thanos Papanicolaou, Achilleas G. Tsakiris
Difference between static and dynamic angle of repose of uniform sediment grains
Pages 149-154
Nian-Sheng Cheng, Kuifeng Zhao
Experiments on the effect of inflow and outflow sequences on suspended sediment exchange rates
Pages 155-170
Michael Müller, Giovanni De Cesare, Anton J. Schleiss
Analyses of trends and causes for variations in runoff and sediment load of the Yellow River
Pages 171-179
Hongling Shi, Chunhong Hu, Yangui Wang, Cheng Liu, Huimei Li
Nutrients accumulation in drainage channel sediments
Pages 180-185
Radovan Savic, Gabrijel Ondrasek, Ljubomir Letic, Vesna Nikolic, Vjekoslav Tanaskovik
Flow structure over a wavy bed with vegetation cover
Pages 186-194
Fazeleh Kabiri, Hossein Afzalimehr, Jueyi Sui
Occurrence of bed load transport in the presence of stable clast
Pages 195-209
Mohd Sofiyan Sulaiman, Shanker Kumar Sinnakaudan, Set Foong Ng, Kyle Strom
Sediment contribution from different geologic formations and land uses in an Iranian small watershed, case study
Pages 210-220
Seyed Hamidreza Sadeghi, Saeed Najafi, Alireza Riyahi Bakhtiari
Copula-based identification of the non-stationarity of the relation between runoff and sediment load
Pages 221-230
Shengzhi Huang, Pei Li, Qiang Huang, Guoyong Leng
Threshold criterion for debris flow initiation in seasonal gullies
Pages 231-239
Yang Wang, Peng Cui, Zhaoyin Wang, Shuangqing Liang
Effect of bed load supply on sediment transport in mountain streams
Pages 240-252
Johannes Kammerlander, Bernhard Gems, Daniel Kößler, Markus Aufleger
Porosity of bimodal sediment mixture with particle filling
Pages 253-259
Weiming Wu, Wei Li
Empirical approaches in prediction of reservoir sediment distribution—An experience of 57 reservoirs in the USA and India
Pages 260-276
Dipankar Chaudhuri
Impacts of artificially planted vegetation on the ecological restoration of movable sand dunes in the Mugetan Desert, northeastern Qinghai-Tibet Plateau
Pages 277-287
Yanfu Li, Zhiwei Li, Zhaoyin Wang, Wenlong Wang, Yanhong Jia, Shimin Tian
Reservoir rehabilitation: The new methodological approach of Economic Environmental Defence
Pages 288-294
Annamaria De Vincenzo, Antonio Jacopo Molino, Bruno Molino, Vittoria Scorpio
Full papers are available at ScienceDirect:
http://www.sciencedirect.com/science/journal/10016279, with free access of the abstracts.
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Mohamed Elhakeem, A.N. Thanos Papanicolaou, Achilleas G. Tsakiris, A probabilistic model for sediment entrainment: The role of bed irregularity, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 137-148, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2016.11.001.
(http://www.sciencedirect.com/science/article/pii/S1001627916301159)
Abstract: Abstract
A generalized probabilistic model is developed in this study to predict sediment entrainment under the incipient motion, rolling, and pickup modes. A novelty of the proposed model is that it incorporates in its formulation the probability density function of the bed shear stress, instead of the near-bed velocity fluctuations, to account for the effects of both flow turbulence and bed surface irregularity on sediment entrainment. The proposed model incorporates in its formulation the collective effects of three parameters describing bed surface irregularity, namely the relative roughness, the volumetric fraction and relative position of sediment particles within the active layer. Another key feature of the model is that it provides a criterion for estimating the lift and drag coefficients jointly based on the recognition that lift and drag forces acting on sediment particles are interdependent and vary with particle protrusion and packing density. The model was validated using laboratory data of both fine and coarse sediment and was compared with previously published models. The study results show that all the examined models perform adequately for the fine sediment data, where the sediment particles have more uniform gradation and relative roughness is not a factor. The proposed model was particularly suited for the coarse sediment data, where the increased bed irregularity was captured by the new parameters introduced in the model formulation. As a result, the proposed model yielded smaller prediction errors and physically acceptable values for the lift coefficient compared to the other models in case of the coarse sediment data.
Keywords: Sediment entrainment; Probabilistic models; Bed surface irregularity; Active layer relative roughness; Packing density; Volumetric fraction of sediment
Nian-Sheng Cheng, Kuifeng Zhao, Difference between static and dynamic angle of repose of uniform sediment grains, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 149-154, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2016.09.001.
(http://www.sciencedirect.com/science/article/pii/S1001627916300543)
Abstract: Abstract
In the investigation of sediment transport, it is necessary to differentiate various definitions of angle of repose (AoR) available in the literature. The static AoR, composed of upper and lower angle of slope, forms just before and after slope instability, while the dynamic AoR can be observed when sediment grains are moving continuously down an inclined plane. In the present study, a series of laboratory experiments was conducted to measure static and dynamic angle of repose for uniform natural sediments with median diameter of 0.28–4.38 mm. The results show that the different slope angles have different characteristics. The upper and dynamic AoR increase slightly with increasing grain diameter, while the lower AoR is not sensitive to changes in sediment size and may assume a constant value. The average of the upper and lower AoR is equivalent to the dynamic AoR, and the difference between them increases with increasing grain diameter. The present study suggests that the different angles of repose should be treated with caution when applying in investigations of bedload transport, dune migration and local scour development.
Keywords: Angle of repose; Avalanche; Sediment transport
Michael Müller, Giovanni De Cesare, Anton J. Schleiss, Experiments on the effect of inflow and outflow sequences on suspended sediment exchange rates, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 155-170, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.02.001.
(http://www.sciencedirect.com/science/article/pii/S1001627917300331)
Abstract: Abstract
In laboratory experiments, the influence of inflow and outflow sequences on the behavior of fine sediment was investigated. The experimental set-up consisted of two interconnected rectangular basins, between which water was moved back and forth. Suspended sediment concentration in the main basin as well as the sediment exchange rates were derived from turbidity measurements.The suspended sediment ratio, SSR, and sediment exchange rates (influx sediment rate, ISR, and evacuated sediment rate, ESR) were measured. In twenty test runs, a parametric study on the magnitude and frequency of inflow and outflow cycles, the relative duration between inflow and outflow sequences, the initial sediment concentration, and the intake position was done. An initial test with stagnant water described the settling behavior of fine sediment and served as a reference scenario.The test results show that settling of fine particles near the intake/outlet structure can be considerably reduced by the nature of the inflow and outflow sequences. High cycle magnitude and frequency lead to maximum suspended sediment ratio in the system. For low discharges, the evolution of suspended sediment concentration cannot be directly correlated to the inflow and outflow cycles. However, compared to “no operation” conditions, the suspended sediment ratio could be increased by 10% to 40% locally. For high discharge, the evolution of suspended sediment concentration correlated with discharge cycles and suspended sediment ratios between 50% and 80% higher than for stagnant water could be achieved. Similar ratios could be obtained when the intake is located closer to the bottom or to the free water surface.Meanwhile, the overall sediment balance remained in equilibrium over the test period, indicating that the influx and evacuated sediment rates are not significantly influenced by the inflow and outflow cycles.
Keywords: Laboratory experiments; Inflow and outflow sequences; Suspended sediment; Sediment exchange rates; Turbidity measurements
Hongling Shi, Chunhong Hu, Yangui Wang, Cheng Liu, Huimei Li, Analyses of trends and causes for variations in runoff and sediment load of the Yellow River, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 171-179, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2016.09.002.
(http://www.sciencedirect.com/science/article/pii/S1001627916300555)
Abstract: Abstract
Due to the impacts of globe climate change and human activities, dramatic variations in runoff and sediment load were observed for the Yellow River. Analyses of nearly 65 years’ data measured at main hydrologic-stations on the Yellow River from 1950 to 2014 indicated that, except for the Tangnaihai station in the head region, sharp downward trends existed in both the annual runoff and annual sediment load according to the Mann–Kendal trend test; and their abrupt changes occurred in 1986 and in 1980, respectively, according to the rank sum test. Factors affecting the changes in the runoff and sediment load were very complicated. Results indicated that the reducing precipitation and the increasing water consumption were the main causes for the runoff decline, while the impoundment of the Longyangxia Reservoir and its combined operation with the Liujiaxia Reservoir exerted a direct bearing on the abrupt change in the annual runoff. In addition to the sediment load decrease associated with the runoff reduction, the reduced storm intensity, the conducted soil erosion control, and the constructed dam buildings all played an important role in the trends and abrupt changes of sediment load decline.
Keywords: Yellow River; Runoff; Sediment load; Variation trends
Radovan Savic, Gabrijel Ondrasek, Ljubomir Letic, Vesna Nikolic, Vjekoslav Tanaskovik, Nutrients accumulation in drainage channel sediments, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 180-185, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2016.07.005.
(http://www.sciencedirect.com/science/article/pii/S1001627917301208)
Abstract: Abstract
The drainage channel network in Vojvodina, northern part of the Republic of Serbia, in total length of around 20,000 km, transfers excessive (under)ground waters from around 2.15 million ha of lowlands. Channels are mostly in direct connection with the surrounding arable agricultural land and are exposed to different run-off, leaching and/or wind erosion processes. Close to urban areas, some channel sections serve as recipients of unrefined sewage and industrial waste waters. Water flows and velocities, as well as the transportable capacity of fluvial materials (sediments) are relatively low. This, in combination with other natural and anthropogenic impacts, contributes to sediment generation in the drainage channel network. Based on around 100 sediment samples from 46 channels, concentrations of primary nutrients (N, P and K) were elaborated in this study. Detected concentrations of macronutrients in the channel sediments (e.g. N 1–1.2%, P 100–265 and K 100–380 mg 100 g-1) exceeded their content in surrounding arable land by a few fold. Also, significantly higher nutrient concentrations (in average by 50%) were detected in downstream (vs. upstream) channel sections. An excessive presence of observed elements in channel sediments, due to interactive processes between water and sediment material, can adversely influence the water quality and life conditions for channel biota and caused other negative environmental impacts such as eutrophication. These results clearly confirm that the processes of nutrient accumulation in channel sediments are greater than those in the surrounding, mostly intensively arable land areas. The erosion of unprotected agricultural areas and sediment transport as the most important pollution pathways from the drainage basin to channel network may be essential factors responsible for detected condition of nutrient accumulation.
Keywords: Drainage channels; Sediments, N, P, K; Erosion
Fazeleh Kabiri, Hossein Afzalimehr, Jueyi Sui, Flow structure over a wavy bed with vegetation cover, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 186-194, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2016.07.004.
(http://www.sciencedirect.com/science/article/pii/S1001627917300446)
Abstract: Abstract
On the basis of experiments carried out in flume with a wavy bed with vegetation cover, flow velocity, turbulence intensities and Reynolds stress distributions are investigated. The wavy bed was similar to dune in this study. The fixed artificial dunes were constructed over the bed and artificial vegetation put over them in a laboratory flume. An Acoustic Doppler Velocimeter and spatially-averaged method were applied to determine turbulent flow components and shear velocity. Results were compared with a gravel bedform. It was observed that vegetation cover influences considerably the flow structure and displays clearly the flow separation and reattachment point. The law of the wall was not valid within the vegetation cover, but it was fitted well to the zone above the vegetation cover within the inner layer. For a wavy bed having the same dimensions, shear velocity and friction factor over vegetation cover are 1.7 and 2.6 times of those for the gravel bedform, respectively. The results of laboratory study were compared with those of river study.
Keywords: Wavy bed; Vegetation cover; Turbulence; Flow separation; Gravel
Mohd Sofiyan Sulaiman, Shanker Kumar Sinnakaudan, Set Foong Ng, Kyle Strom, Occurrence of bed load transport in the presence of stable clast, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 195-209, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.02.005.
(http://www.sciencedirect.com/science/article/pii/S100162791630141X)
Abstract: Abstract
It is well-versed that transport occurrence is vital for in stream rehabilitation, river restoration and installment of sediment sampler on river beds. Current practice emulates the use of continuous prediction using reach-averaged approach. However, prediction of transport occurrence entails the use of binary model through the execution of logistic regression analysis. Bed load and turbulence data were physically measured at mountainous region with divergent surface bedform in its presence. The parameterization and statistical approaches are treated in the similar fashion with multiple regression except for the test for model fit and model selection criterion. The parameters on near-bed turbulence characteristics at the entrainment threshold were assigned as independent variables containing 15 predictors. Almost 80 models were generated by selecting the best possible combination in accordance with the statistical precaution of alleviating multicollinearity issue. It is postulated that the model containing shields stress in the form of turbulent kinetic energy (TKE) at vertical direction and fractional time for second quadrant provides better estimation of potential location for greatest sediment-entrainment; hence a high possibility for transport occurrence.
Keywords: Logistic regression analysis; Transport occurrence; Bed load; Entrainment; Local bed shear
Seyed Hamidreza Sadeghi, Saeed Najafi, Alireza Riyahi Bakhtiari, Sediment contribution from different geologic formations and land uses in an Iranian small watershed, case study, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 210-220, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.02.002.
(http://www.sciencedirect.com/science/article/pii/S1001627917300343)
Abstract: Abstract
Many intra and extra problems occurred due to unsustainable human use of natural resources leading to increasing sediment loads in the watersheds. However, few studies have been comprehensively conducted in progressing countries to prioritize sediment sources from different points of views, particularly in some countries like Iran where such valuable information is essential for proper watershed resources management. The present study was therefore planned to assess the importance of potential sediment sources viz., spatial sources (geologic units) and source types (land use units) in sediment yield in Idelo watershed as one of the important sub-watersheds of Sefidrood large Watershed in Zanjan Province, Iran, using composite fingerprinting. In addition, the results of the sediment fingerprinting approach were compared with those of field measurement data obtained from studying soil erosion types (viz., sheet, rill and gully erosion). Toward this attempt, 16 tracers were detected in different geologic units and land uses and the sediment yielded at the watershed outlet. The results showed that the composite fingerprints of the different geologic units comprising As, N, Cu, Zn, OC and Co tracers could correctly distinguish 86% of the sediment source samples. The red gypsiferous marl contributed 85 percent in sediment yield. In regard to source types, the optimum composite fingerprint encompassed only N and Cu and provided a discriminatory efficiency of 90%. Besides that, the rangelands with 48.8% study area coverage had a significant contribution of 88% in sediment yield. The field measurements confirmed the reliability of results of fingerprinting approach in apportioning watershed scale sediment sources on the base of consistency of the two sets of results. It was also understood from the results, besides successful applicability of composite fingerprinting in assessing the provenance of the sediment yielded at the watershed outlet that the geologic formations and land use types played different roles in sediment yield. Such information helps managers and decision makers to properly regulate appropriate and adaptive management approaches in the study watershed.
Keywords: Composite fingerprinting; Multivariate mixing model; Soil erosion; Spatial sources; Source types
Shengzhi Huang, Pei Li, Qiang Huang, Guoyong Leng, Copula-based identification of the non-stationarity of the relation between runoff and sediment load, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 221-230, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.03.001.
(http://www.sciencedirect.com/science/article/pii/S1001627917300641)
Abstract: Abstract
It is important to identify the non-stationarity in the relation between runoff and sediment load under the backdrop of the changing environment. This relation helps to further understand the mechanisms of runoff and sediment yield. A copula-based method was used to detect possible change points in the relation between runoff and sediment load in the Wei River Basin (WRB), China, where soil erosion is a very severe issue. The modified Mann-Kendall trend test method was applied to obtain the trends of runoff and sediment load spanning 1960–2010 at monthly and annual timescales. Finally, the causes of the identified non-stationarity of the relation between runoff and sediment load were roughly analyzed from the perspective of climate change and human activities. Results indicated that: (1) the runoff and sediment load in the Jinghe and Wei rivers were generally characterized by noticeably decreasing trends at both monthly and annual timescales; (2) both the Jinghe and Wei rivers had a common change point (2002), implying that the stationarity of the relation between runoff and sediment load in the Jinghe and Wei River was invalid; (3) human activities including increasing water consumption and growing application of soil conservation practices are dominant factors resulting in non-stationarity in the relation between runoff and sediment load in the WRB. This study provides a new idea for identifying the non-stationarity of multivariate relation in the hydro-meteorological field under the background of the changing environment.
Keywords: Copula-based method; Runoff; Sediment load; Non-stationarity; Change point; Human activities
Yang Wang, Peng Cui, Zhaoyin Wang, Shuangqing Liang, Threshold criterion for debris flow initiation in seasonal gullies, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 231-239, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.03.003.
(http://www.sciencedirect.com/science/article/pii/S1001627917300677)
Abstract: Abstract
A series of flume experiments were done to investigate the effect of grain composition on the critical gradient and discharge of debris flows initiated in seasonal gullies. The results indicated that the critical gradient and discharge for debris flow initiation decrease initially, and then increase as the mass content of fine particles (<2 mm) increases. As the mass content of fine particles increases, the angle of repose, permeability of widely graded gravel soils, and the incipient motion conditions of the coarse grains in non-uniform sediments decrease at first, and then increase. The mass content of fine particles of all inflection points is the same. The theoretical model based on the combination of hydrodynamic force and shear stress is more applicable to the prediction of the critical gradient for debris flow initiation. The critical discharge model considering the effect of non-homogeneity of the soil and the size of coarse and fine grains provides a more accurate prediction of debris flow initiation than other models based on the mean diameter.
Keywords: Grain composition; Seasonal gully; Non-uniform sediment; Debris flow initiation; Critical gradient; Critical discharge
Johannes Kammerlander, Bernhard Gems, Daniel Kößler, Markus Aufleger, Effect of bed load supply on sediment transport in mountain streams, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 240-252, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.03.004.
(http://www.sciencedirect.com/science/article/pii/S1001627917300781)
Abstract: Abstract
Mountain streams with their tributary torrents build the upper part of the fluvial network. They are important regarding the transfer of sediment from headwaters to lower basins. Channels are typically steep with wide grain size distributions, ranging from fine sand up to large boulders, and a stabilized bed surface. Mountain streams often are supply-limited with respect to mobile bed load, which needs to be addressed when bed load transport equations are applied to such streams. To better understand supply limitation, laboratory experiments highlighting the effect of bed load supply on incipient motion and bed load transport rate are discussed. Experimental tests were done in which fine bed load was supplied to a previously armored channel bed, with flow conditions ranging from one-third to twice the critical discharge for the bed surface. At flows not exceeding the critical discharge, the time series of the bed load transport rate at the downstream model boundary featured consistent patterns which are attributed to distinct phases: (i) a temporal lag, (ii) an equilibrium state, and (iii) a post-supply phase. Bed load transport occurred even at flows distinctly below that for incipient motion of the bed surface. But, with the mass of total bed load outflow approaching the supply amount, the mass did not exclusively consist of supplied grains. The coarser the supplied bed load, the more sediment was mobilized from the bed surface. At higher flows, processes differed. Total bed load outflow exceeded the supply amount and the break-up of the armor layer caused a refining of the bed surface.
Keywords: Bed load transport; Bed load supply; Mountain stream; Experimental modeling
Weiming Wu, Wei Li, Porosity of bimodal sediment mixture with particle filling, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 253-259, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.03.005.
(http://www.sciencedirect.com/science/article/pii/S1001627917300793)
Abstract: Abstract
The porosity of a bimodal sediment mixture is affected by the filling of fine particles in the voids of coarse particles when the particle size range is wide. The classical ideal packing models tend to overestimate the filling, and, thus, underestimate the porosity of the mixture. In this study, an existing random filling model is improved by considering a three-dimensional packing configuration, and a new model is developed by considering how many fine particles are required and how many are available to cover the surface of coarse particles in the sediment mixture. The developed models are validated using measured data and compared with existing models. The new model can reproduce well the variation trend of the mixture porosity as the fraction of fine particles varies.
Keywords: Bimodal sediment mixture; Porosity; Particle filling; Particle packing
Dipankar Chaudhuri, Empirical approaches in prediction of reservoir sediment distribution—An experience of 57 reservoirs in the USA and India, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 260-276, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.04.001.
(http://www.sciencedirect.com/science/article/pii/S1001627916300737)
Abstract: Abstract
An accurate prediction of sediment distribution may minimize economic losses through proper and timely planning of the functional activities of a reservoir. This study assesses different temporal and spatial factors that affect for sediment deposition in a reservoir and its distribution. This study also focuses on evaluation of two popular distribution prediction methodologies, Area Increment and Empirical Area Reduction, based on experience with sediment distribution in 57 reservoirs in the USA and India. A non-iterative processed empirical distribution model (NPEDM) and a linear regression trend model (LRTM) are proposed to predict sediment distribution. Silt contributing area and inflow entering a reservoir are found to be the most significant factors affecting in reservoir sediment deposition. Compared to the Empirical Area Reduction method, the Area Increment method provided better prediction. The reservoir classification approach and empirical design distribution type curves given by Borland and Miller (1960) are found to be rational. Shape factor values for different periods indicate that reservoir shape (type) changes with time. Thus, long term prediction is not desirable in Type-II & III reservoirs using the Empirical Area Reduction method. Newly developed the NPEDM shows reasonably good prediction of sediment distribution. The NPEDM is very easy to apply and can be used in any reservoir of any size. Extrapolation of the trend of sediment distribution obtained from the LRTM indicates an accurate short term prediction in a few reservoirs as causes of temporal and spatial variations of sediment distribution including the factors of uncertainties of sediment deposition are implicit within the methodology.
Keywords: Deposition factors; Temporal and spatial variations; Trend projection; Model performance; Type curve; Relative depth
Yanfu Li, Zhiwei Li, Zhaoyin Wang, Wenlong Wang, Yanhong Jia, Shimin Tian, Impacts of artificially planted vegetation on the ecological restoration of movable sand dunes in the Mugetan Desert, northeastern Qinghai-Tibet Plateau, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 277-287, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2017.02.003.
(http://www.sciencedirect.com/science/article/pii/S1001627917300379)
Abstract: Abstract
Controlling desertification is an important ecological target for the Qinghai-Tibet Plateau of China, where studies on impacts of vegetation restoration measures on sandy soil improvement are still lacking. The Mugetan Desert in Guinan County, Qinghai Province, northeastern Qinghai-Tibet Plateau is a representative ecological restoration area. The impacts of artificial vegetation on the ecological restoration and its properties are studied by using field investigation and sample testing including contents of the surface layer and the vegetation composition of movable, semi-fixed, and fixed sand dunes. Results demonstrate that the moss crust has formed on the surface of a sand dune which has become fixed after 30 years under the impact of artificial vegetation (i.e. Cathay poplar). Meanwhile, the clay minerals, organic matter, and other soil available nutrients have markedly increased. A correlation has been found between these materials, i.e., clay minerals and organic matter content increasing with silt and clay increases with reduction in sand content. In addition, soil nutrient were positively correlated with the increase of plant diversity.Under the current meteorological conditions, the artificial vegetation is helpful for the stabilization of sand dune and the ecological restoration in the Mugetan Desert.
Keywords: Desertification; Sand dune; Artificial vegetation; Ecological restoration; Biological crusting layer; Soil available nutrients
Annamaria De Vincenzo, Antonio Jacopo Molino, Bruno Molino, Vittoria Scorpio, Reservoir rehabilitation: The new methodological approach of Economic Environmental Defence, International Journal of Sediment Research, Volume 32, Issue 2, June 2017, Pages 288-294, ISSN 1001-6279, https://doi.org/10.1016/j.ijsrc.2016.05.007.
(http://www.sciencedirect.com/science/article/pii/S1001627917300549)
Abstract: Abstract
This paper proposes a new methodological approach to silted reservoir management and defence, which combines the reservoir rehabilitation process and the utilization of the recovered water volumes and sediments. This approach, strategic from both the economical and environmental points of view, is here defined as Economic Environmental Defence (EED) of a reservoir. The EED approach is applied to the case study of Guardialfiera reservoir, where the available experimental data allowed the estimation of siltation up to date, the analysis of the distribution of sediment particle size along the reservoir bottom and the possibility to propose a feasible utilization of water and sediments resulting from the reservoir rehabilitation.
Keywords: Reservoir siltation; Reservoir rehabilitation; Sediment and water utilization