Numerous approaches to local scour forming studies have been developed. This paper presents different scientific approaches to the scour phenomenon using Lane’s relation [1] in its modified form during laboratory studies. The original Lane’s relation is applicable in dynamic balance conditions in alluvial rivers context, and it is not an equation, but a qualitative expression which cannot be directly used to estimate the influence of a change in one parameter on the magnitude of others. Lane's relation, despite its qualitative and simplified character, serves well to describe the nature of the process of forming alluvial stream channels, while modified relation allows transforming it into an equation for laboratory studies of local scour forming in prearranged clear-water equilibrium conditions and gives a new opportunity for this principle application.

Numerous approaches in sediment mobility studies highlighted the key meaning of channel roughness, which results not only from bed material granulation but also from various bed forms presence, caused by continuous sediment transport. Those forms are strictly connected with the intensity of particle transport, and they eventuate from bed shear stress. The present paper comprised of local scours geometric dimensions research in three variants of lengthwise development of laboratory flume in various hydraulic properties, both in “clear-water” and “live-bed” conditions of sediment movement. Lots of measurements of the bed conformation were executed using the LiDAR device, marked by a very precise three-dimensional shape description. The influence of the bed shear stress downstream model on scours hole dimensions of water structure was investigated as one of the key factors that impact the sediment transport intensity. A significant database of 39 experimental series, lasting averagely 8 h, was a foundation for delineating functional correlations between bed shear stress-and-critical shear stress ratio and geometry properties of local scours in various flume development cases. In the scope of mutual influence of bed shear stress and water depth, high correlation coefficients were attained, indicating very good and good functional correlations. Also, the influence of bed shear stress and the total length of the scour demonstrated a high correlation coefficient.

During the past four decades the use of nonwoven geotextiles as filter materials in geotechnical works has experienced a marked increase. In this study, the water permeability coefficient of nonwoven geotextiles after 23 years of exploitation in drainage system was determined to evaluate the influence of physical clogging on filtration performance of geotextiles. The obtained results showed that the geotextiles were clogged by soil particles. What is more, the objective in this study was to establish a gradient ratio test method for estimating a clogging phenomenon of geotextile filter adequately. A series of gradient ratio tests on three kinds of needle-punched nonwoven geotextile filters whose number of constrictions differs was performed. A geotextile filter was put under a silty sand layer. Based on the test results, it was confirmed that the water permeability coefficient became small as the gradient ratio increased, depending on the number of constrictions of the geotextile. It was also found that the modified gradient ratio GR₄ is more sensitive than GR₈ and GR₂₅. Based on interpretation of the experimental results, the authors recommend the acceptance limit of GR₈ equal to 3.7 and of GR₄ equal to 4.8.

Alluvial river channels undergo transformations due to fluvial processes such as water flow which invokes soil particles movement. Mentioned processes are interrelated and can be described as a feedback relation which means that hydraulic and morphological features adjust to each other during the process of obtaining the dynamic balance between water flow and sediment transport intensity. The dynamic balance phenomenon was described qualitatively by Lane (1955). Local scour can form in the riverbed as a result of a dynamic balance loss. Despite considerable scientific research in various physical model cases and a wide range of hydraulic and ground conditions, universal guidelines of scour shape properties calculations remain unknown. Therefore, a more extensive investigation of the phenomenon is needed. The paper proposes an empirical model based on Lane's relation, that allows to obtain functional correlation and which can be used in local scour basic geometry properties description formed in an alluvial flume with sandy bed, in steady flow conditions, using various water structure models. A device, made by the Authors, equipped with a laser scanner was used for bed investigations.

Among the various types of polymeric materials, geosynthetics deserve special attention. A geosynthetic is a product made from synthetic polymers that is embedded in soils for various purposes. There are some basic functions of geosynthetics, namely, erosion control, filtration, drainage, separation, reinforcement, containment, barrier, and protection. Geosynthetics for erosion control are very effective in preventing or limiting soil loss by water erosion on slopes or river/channel banks. Where the current line runs through the undercut area of the slope, the curvature of the arch is increased. If this phenomenon is undesirable, the meander arch should be protected from erosion processes. The combination of geosynthetics provides the best resistance to erosion. In addition to external erosion, internal erosion of soils is also a negative phenomenon. Internal erosion refers to any process by which soil particles are eroded from within or beneath a water-retaining structure. Geosynthetics, particularly geotextiles, are used to prevent internal erosion of soils in contact with the filters. Therefore, the main objective of this review paper is to address the many ways in which geosynthetics are used for erosion control (internal and external). Many examples of hydrotechnical and civil engineering applications of geosynthetics will be presented.