Temporary or demountable systems should only be used where a permanent system is not viable. They should not be relied on to replace permanent systems. They can be useful when a flood occurs, but have their limitations. The prepared foundation is critical to the effectiveness of a demountable levee system. As with floodwalls, the hydraulic gradient under the structure could be high. They would typically require a concrete slab foundation and approach slab. The construction of temporary levees may cause new problems. As they alter the natural or modelled flow of water, adding additional levees to a system makes it more difficult to predict where floodwaters may travel, their potential impacts and, consequently, how emergency services should react. Sandbags Sandbags provide the most common temporary levee system. They are regularly used to reduce the impact of low-level flooding on private homes. Sandbags will not stop the water completely, but can reduce the amount of water entering a home or area if placed correctly in appropriate strategic locations. Sandbags are also regularly used to top-up low points or to increase the freeboard on earthen levees. However, incorrect or excessive use of sandbags on a levee increases the risk of levee failure. More detailed advice on the use of sandbags to place sandbags, how to fill and lay sandbags, what to do with them after the flood has passed) is available on the VICSES website. Temporary earthen banks These may only be constructed at the direction of the Incident Controller during a flood event. They should be removed as soon as practicable after the event has ended. Proprietary products Non-permanent forms of barrier for flood protection can provide much-needed flexibility and increased opportunities for effective management of a wide range of floods. New temporary and demountable systems have been developed, each with its own features, particular standard and quality. Guidance should be sought from the manufacturer or supplier regarding the potential advantages and disadvantages for a particular application before opting to rely on a proprietary product. The manufacturer’s instructions should be observed for installation, operation and storage.
Temporary or demountable systems should only be used where a permanent system is not viable. They should not be relied on to replace permanent systems. They can be useful when a flood occurs, but have their limitations. The prepared foundation is critical to the effectiveness of a demountable levee system. As with floodwalls, the hydraulic gradient under the structure could be high. They would typically require a concrete slab foundation and approach slab. The construction of temporary levees may cause new problems. As they alter the natural or modelled flow of water, adding additional levees to a system makes it more difficult to predict where floodwaters may travel, their potential impacts and, consequently, how emergency services should react. Sandbags Sandbags provide the most common temporary levee system. They are regularly used to reduce the impact of low-level flooding on private homes. Sandbags will not stop the water completely, but can reduce the amount of water entering a home or area if placed correctly in appropriate strategic locations. Sandbags are also regularly used to top-up low points or to increase the freeboard on earthen levees. However, incorrect or excessive use of sandbags on a levee increases the risk of levee failure. More detailed advice on the use of sandbags to place sandbags, how to fill and lay sandbags, what to do with them after the flood has passed) is available on the VICSES website. Temporary earthen banks These may only be constructed at the direction of the Incident Controller during a flood event. They should be removed as soon as practicable after the event has ended. Proprietary products Non-permanent forms of barrier for flood protection can provide much-needed flexibility and increased opportunities for effective management of a wide range of floods. New temporary and demountable systems have been developed, each with its own features, particular standard and quality. Guidance should be sought from the manufacturer or supplier regarding the potential advantages and disadvantages for a particular application before opting to rely on a proprietary product. The manufacturer’s instructions should be observed for installation, operation and storage.
DEP-8419-Levee-design-construction-and-management-guidelines_FA_web-VBrev-150310.docx