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<br />OM 500-1-6 <br />January 1991 <br /> <br />. <br /> <br />heavy equipment would be difficult or impossible. A small supply of these jacks, <br />cable, etc., is maintained by the Albuquerque District at the Jemez Canyon Dam, <br />and a few other projects. Contact the Emergency Management Branch, (505) 766- <br />3829, to coordinate the issue and use of steel jacks. <br /> <br />(5) Rockfille,d Cribs. Rockfilled cribs are an alternate method of <br />providing caving bank protection. These may be constructed of driven stakes and <br />wire fencing and then filled with rock. Gabions may be used to construct <br />deflection dikes if available, Gabions are patented wire baskets which can be <br />filled with rock on the bank and then can be pushed into the water. The <br />Albuquerque District maintains a small stock of gabions for flood fight use. <br /> <br />h. Debris Removal. Large trees and other debris often lodge at bridge <br />openings, creating serious and immediate threats during a flood. Such problems <br />should be dealt with promptly by removing or dislodging the debris. Large trees <br />may run aground near a levee or natural bank and deflect flood flows unexpectedly <br />into the bank or levee. Such an obstruction should be pulled to the bank, or <br />completely out of the channel if possible, <br /> <br />i. Topping. Immediate consideration should be given to the grade line <br />of each levee section. When available, a study of high-water profiles and levee <br />grades will show where low places in the levee exist. If it is considered <br />desirable to increase the grade of the levee to expected high-water elevations, <br />emergency topping may be done (1) with sacked earth; (2) with lumber and sacked . <br />earth; (3) with mud boxes; (4) by raising crown of levee with borrow material. <br />(See Plates B-1, B-2, and B-3, respectively.) When evaluating the method and <br />degree of levee raise actions, it is important to consider the need to maintain <br />a useable vehicle passage along the levee top, and the need for a minimum <br />clearance beneath power lines or bridges which span the levee, <br /> <br />(1) Sandbag Topping. If lumber is not available, a sandbag topping <br />may be used to raise the crown of the levees about three feet. The bags should <br />be laid stretcher-wise or along the levee for the first layer, crosswise for the <br />second layer, and so on. The bags should be lapped at least 1,3 either way and <br />well mauled into place. When properly stacked and tamped, one bag will give <br />about a three-to-four inch topping. If gravel is available, it should be used <br />for the front facing to avoid washing out. <br /> <br />(2) Lumber and Sandbag Topping. This is the most commonly used <br />method of raising low reaches in emergencies. In putting on this topping, as <br />well as any other topping, a careful line of levels should be run and grade <br />stakes set in advance. Two-by-four or two-by-six inch stakes should then be <br />driven on the riverside of the crown six feet apart, and one-by-twelve inch <br />boards nailed to the landslide of the stakes, This wall, backed with a single <br />tier of sandbags, will hold out at least one foot of water. If the second foot <br />is necessary the layer of sandbags will have to be increased in number and <br /> <br />. <br /> <br />6 <br />