Laserfiche WebLink
<br /> <br />material by hand in wheelbarrows or other devices. <br /> <br />Notes <br /> <br />During extended high water events, the mudbox may deterio- <br />rate, particularly if standard grades of plywood are used. For <br />extended high water conditions, serious consideration should be <br />given to the use of marine grade materials which may increase the <br />cost of the project as much as ten-fold. <br /> <br />Mudboxes are subject to erosion problems if waves overtop the <br />construction. In order to maintain the integrity of the mudbox, <br />erosion of the fill must be monitored and corrected. Sandbags or <br />added poly covers may be used to limit or reduce fill erosion. <br /> <br />Plans to construct these four forms of capping can be found in <br />the appendix. It is important to select the best capping method for <br />any given situation. No single method is "the best" to use on all <br />levees or in all water conditions. Technical assistance on the best <br />method to use in any given situation can be obtained from the <br />Corps of Engineers. <br /> <br />The majority of rivers do not have levees or other flood control <br />structures. Yet floods still occur on these flowages. Unlike levees <br />where the crown has a set grade, open areas have highly variable <br />grades which increases the difficulty of constructing expedient <br />flood works. It is important for survey crews or engineers to set <br />grade lines and heights for any flood works set in open areas. <br />DW'ing construction, these lines must be closely monitored and <br />followed by all flood fight teams. <br /> <br />Flashboards and mudboxes are generally not used in open <br />areas. These structures are difficult to adapt to changing grades. <br />- - -- - -~ ------othermethmts---arefaster and eaID:eTIo construct. -since sandbags - <br />are so versatile, they are commonly used in open areas for <br />expedient flood protection. But with all sandbag operations, this <br />process is very labor intensive and may require more time than is <br />available. <br /> <br />If a roadway or other surface with the capability of supporting <br />heavy equipment is present, an expedient levee may be construct- <br />ed. An expedient levee can be laid on roadways, park land, or <br />other open areas where access can be made and rights of way <br />obtained. After the area has been surveyed, the levee is construct- <br />ed in one foot increments preferably using cohesive materials such <br />as clay. Each layer is compacted before the next layer is placed <br />down. At a minimum, the base of the expedient levee should be <br /> <br />Page4-9 <br />