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6.3A Page 15 It is imperative that the San Mateo County Office of Emergency Services be kept abreast of the staffing, equipment, and supply needs of the City so that available resources at the state and federal levels of government can be made available to the City in a timely manner. It is likewise imperative that the City Manager, in his capacity as director of emergency services for the City, be constantly advised of the status of the flood fighting effort and prospective need for outside assistance not immediately available locally. The Public Works Services Director shall monitor the availability of flood fighting personnel, supplies, and equipment at the local level in cooperation with the San Mateo County Office of Emergency Services. VII. Flood Fiahtina Methods The main causes which may contribute to levee failure during periods of high water or flood flows are: seepage through or under the dikes of sufficient magnitude to cause a "boil", leaks through the levees caused by burrowing animals, erosion of the levees due to current or wave action, and overtopping as a result of adjacent water surface or wave elevations in excess of levee height. The various methods used to prevent levee failure are known as flood fighting methods. The methods of flood fighting described in the following paragraphs are consistent with practices by the California State Department of Water Resources and the U.S. Army Corps of Engineers. A copy of the Flood Fighting Methods, dated August 2003, by California State Department of Water Resources is attached as Exhibit 0 for reference. A. Boils A boil is a condition whereby enough pressure is produced by a high water stage so that water is piped through or under the levee with sufficient velocity to carry earthen material to the landward side. These danger spots are serious if sand and other material are being carried in suspension by the discharging water. If not controlled, these particles of earthen material will be eroded from within the levee at an accelerated pace, thus causing a local subsidence of the levee section. The continuation of this process will eventually result in a break in the levee by allowing the flood waters to flow directly over the crest or through the levee. The common method of controlling boils consists of building up a watertight sack ring around the boil to a height necessary to reduce the velocity of flow in which earth material is no longer discharged from the boil. The flow of water should never be stopped completely, because this may cause the boil to "break out" in an area adjacent to the existing sack ring. The sack ring around the boil should be large enough to effectively encompass the defective area immediately surrounding the discharge spot. If several boils of sufficient force to displace sand or earth are 8 April 2008