Weir is installed across a river with the general purpose of controlling water level and water intake. Most weirs installed on rivers are fixed weirs and hinder water flow to bring about sedimentation of earth and sand and deterioration of water quality causing destruction of the river environment. Due to such reason, movable weir which can control reservoir capacity has been developed recently and increasingly installed instead of existing fixed weir and various studies have been carried out to develop methods for self-purification effect and reducing sedimentation of earth and sand.<br>From movable weir, rubber dams have been used in many construction sites due to ease of maintenance administration but if the rubber sheet is damaged artificially or by natural disaster, harm is done to the river and high maintenance and repair costs are incurred if neglected for a long time. Also, the life expectancy of a rubber dam is over 30 years so appropriate management and maintenance administration are required to secure safety of the river and proper water procurement.<br>This study developed rubber sheet for improvement of maintenance and repair for rubber dam which is repaired most often for purpose of irrigation and water intake in rivers and such results are as follows.<br>As a result of investigating repair cases when operating rubber dams, repair cases for poor assembly of rubber panel was only about 3.5% of all cases while there were no reported cases of self-defect of rubber dams. From a total of 19 cases of rubber dam repairs, 12 cases (63.2%) were due to external conditions so it is determined that rubber sheet development is needed for improving the durability and safety of rubber dams. Regarding such finding, this study developed a rubber dam enabling bullet resistance/cut resistance by adding aramid sheet when producing rubber sheet and enabled abrasion check by coating the outer layer with colored synthetic rubber.<br>As a result of developing rubber sheet for improving maintenance and repair of rubber dams, durability and safety were found to be better than existing rubber dam while there were effects of ease of maintenance administration and greater economic efficiency as well. For continuous and permanent use of rubber dams, it is determined that systematic research and continuous development are necessary.

Although flood and drought have ceaselessly taken place, recently the scale of disasters by them has become incomparably bigger than that of the past, and frequency of flood has rapidly on the increase (Harim et al, 2013). According to National Emergency Management, the frequency of torrential downpours over 30mm per hour was average 3.8 times for last 30 years and average 5.2 times for recent 5 years. Number of days with localized torrential downpour over 80mm per day has increased by 1.5 times for the same period. In addition, recently with the change of climate in Korea, the severity of drought has intensified in 6- to 7-year cycle and, with such reasons as excessive intake of stream water, streams are drying up, especially during spell of dry weather (Maeng, Seung Jin et al, 2013). Even though the government, as countermeasures for these problems, has made efforts to prevent disasters by establishing Water Resources Integrated Development 10-year Plan and Water Resources Long-term Integrated Development Plan, implementing Stream & River Improvement Projects and constructing multi-purpose dams, there are difficulties to promptly cope with rapidly changing weather conditions, requiring urgently measures to minimize damages from droughts and floods. This study developed Portable Multi-purpose Water Barrier (Pocket Dam) which can promptly cope with floods and localized torrential downpour, secure agricultural water by temporarily blocking irrigational channel and drainage during drought and has wide applicability to various areas. To develop Portable Multi-purpose Water Barrier, this study i) selected ultra-light materials for easy mobility ii) chose optimum standards applying MIDAS program iii) verified safety features through field applications. For the maximization of blocking effect as well as the lightening of product, Sol Tarpaulin (PVC-coated polyester) was selected that has endurance against water pressure and excellent gripping force on irregular ground bottom. In addition, by using 3-dimensional structural program MIDAS, the barrier was designed in such a structure that it will not be destroyed or pushed behind by water pressure. As the result of the application of developed barrier on Dorim stream in Gwanak-gu and underground parking lot in Kwangjin-gu, Seoul, the barrier was not destroyed or pushed behind, and, instead, it maintained constant standing position and blocked water, proving that it has diverse applicability in addition to safety features in structure and material.