River restoration refers to the environmental and ecological aspect of river engineering and aims to improve the natural habitat of a river system using eco-friendly methods. This paper introduces a new river restoration technique for bank protection and restoration of meander bends by combining a permeable groin with a triangular vane. Nine different combinations of permeable groins with triangular vane including three different effective lengths and three angles of vane were investigated in a 180° mild laboratory flume bend in clear water conditions. Based on experimental tests, scour geometrical patterns were analyzed, classified, and compared with each other. This analysis showed that a triangular vane dramatically enhances the performance of the permeable groin to protect the outer bank from erosion. Then, using Buckingham’s theorem of the dimensional analysis and the incomplete self-similarity (ISS) condition, generalized functional relationships for estimating scour main characteristics around an enhanced permeable groin (EPG) were deduced. This analysis showed that scour patterns depend on the upstream densimetric particle Froude number ($A_{50}$ ) and the ratio between the effective lengths of the triangular vane and the permeable groin ($L_t/L_p$ ). The results showed that scour geometric characteristics estimated by the proposed equations agree reasonably well with the experimental values.

The Nowshahr port in the southern coastlines of the Caspian Sea is among the oldest northern ports of Iran, first commissioned in the year 1939. In recent years, this port has been faced with severe sedimentation issues in and around its entrance that has had negative impacts on the operability of the port. The present study aims at identifying major reasons for severe sedimentation in the port entrance. First, field measurements were evaluated to gain an in-depth view of the hydrodynamics of the study area. Numerical models then were calibrated and validated against existing field measurements. Results of numerical modeling indicated that wind-induced current is dominant in the Caspian Sea. The numerical results also indicated that in the case of an eastward current direction, the interaction between current and the western breakwater arm would lead to the formation of a separation zone and a recirculation zone to the east of the port entrance region. This eddying circulation could transport suspend settled sediments from eastern shoreline towards the port entrance and its access channel. The results of this paper are mostly based on the study of current patterns around the port in the storm conditions incorporate with the identification of sediment sources.

Previous research studies have shown that abutment scour makes a major contribution in bridge failures. Protecting bridges against scour is therefore a priority need. For existing bridges, armoring methods, such as riprap, have a wide application. In the areas where providing stones is expensive, concrete blocks or similar techniques are often used. In the present study the application of the Six Legged Concrete (SLC) elements was experimentally investigated. The SLC elements were placed in three different densities (open, medium and dense) at three different placement depths (h/l=0, 0.5 and 1; where h is the element installation height above the bed and l is element height). Each alternative was tested under different flow conditions for a wing-wall abutment. In general, the results showed that the SLC elements can considerably reduce the scour under different flow conditions. In an optimal arrangement, the elements reduced the scour depth at abutment nose up to 100%. The maximum reduction of scour depth was obtained when the SLC elements were placed densely on the bed (h/l=1).