COMPARISON OF SILL AND REVETMENT IN REDUCING SHORE EROSION AND WAVE OVERTOPPING

Sills (low–crested rubble mounds) are constructed to protect eroding bluffs and planted marshes in living shoreline projects (http://mycopri.org). Revetments are conventionally used to protect eroding shores and reduce wave overtopping and damage to backshore areas. However, revetment construction may result in loss of buffering wetlands. On the other hand, no established method exists to design the sill geometry (crest height, width and side slopes) and its distance from the eroding shore. This study compares the efficacies of the two different rubble structures with the same number of stones in order to clarify their similarity and difference for the purpose in reducing shore erosion and wave overtopping.

Study of Community Capacity in Dealing with The Threat of Shore Erosion in Kragan Subdistrict Rembang District

The shore erosion in Rembang District during 2003-2014 resulted in huge losses. This study was conducted in the Coastal District of Kragan because of frequent shore erosion. Coastal of Sumurtawang and Kragan have erosion. Coastal of Pandangan Wetan, Balongmulyo, and Tanjungan are stable due to the construction of a small port in the village of Karanganyar which affects the surrounding area. The capacity of indigenous knowledge is as high as local wisdom, perception and attitude of the community in handling shore erosion. Coping strategies is also as high as the value of human capital, social, financial, natural, and physical. There is a correlation between community capacity variables, it means that if the capacity of indigenous knowledge is high, then the coping strategies is also high. But, the capacity of indigenous knowledge does not significantly affect the coping strategies. The relation of these capacities determines the priority of settlement.

TƯƠNG QUAN XÓI LỞ - BỒI TỤ MỘT SỐ KHU VỰC LÒNG SÔNG TIỀN, SÔNG HẬU

Correlation of erosion - aggradation in areas along Tien and Hau RiversRiverside erosion, one of the most severe natural disasters, has been occuring along the banks of Tien river and Hau for many years. Many segments in Tan Chau, Hong Ngu, Sa Dec,… are seriously affected by the disaster. There are numbers of studies that have indentified levels, causes of the erosion process and proposed solutions for the decrease of erosional negative influences. Based on analysing satellite images, map, monitoring a series of channel cross - sections by echosounder and the study of geomorphology, the study concluded that erosion and deposition, specific natural processes of braided and meandering river in flood plains, balance one another. Bulding stone jetties and uncomprehensive management have accelerated both two processes: erosion and deposition. Combining the dredge river bed and exploitation of materials for construction is the most effective solution to reduce river shore erosion.