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<br /> <br />meandering channel. Some progress has been made in mapping, regulating and managing <br />fans consistent with their true hazard. <br /> <br />Federal <br /> <br />In 1982, the National Flood Insurance Program (NFIP) commissioned a study of mapping, <br /> <br /> <br />modeling and land management standards for alluvial fan areas. The study resulted in the <br /> <br /> <br />development of suggested management standards for these zones on the fan: a channelized <br /> <br />zone, a braided zone and a sheet flow zone (see Figure 3-1, Appendix 3-A). In addition to <br /> <br /> <br />this study, the NFIP has promulgated mapping guidelines for flood insurance study <br /> <br /> <br />contractors (see Appendix 3-B). FEMA's Region X has also drafted a model ordinance for <br /> <br />communities with alluvial fan flood problems (see Appendix 3-C). This has been presented <br /> <br /> <br />to several communities. <br /> <br />The U.S. Geological Survey and the Corps of Engineers have also mapped some <br /> <br /> <br />alluvial fan areas and arc working on alluvial fan mapping methods. <br /> <br />State <br /> <br />State efforts to develop special maps and regulations for alluvial fans have been <br /> <br /> <br />limited, although Colorado has recommended to local governments a model ordinance ad- <br /> <br /> <br />dressing fans and other geological hazard areas (see Appendix 3-D). <br /> <br /> <br />California's geologic hazard investigation and reporting system requires local gov- <br /> <br /> <br />ernments to identify and regulate geologic hazard areas. This requirement applies to some <br /> <br />types of hazards on the fans. Developers seeking a building permit or subdivision ap- <br /> <br /> <br />proval for projects on fans must have a certified geologist prepare a geologic report assur- <br /> <br /> <br />ing the risk. <br /> <br /> <br />Nevada has developed an alluvial fan management handbook for local governments <br /> <br /> <br />but has not adopted regulatory requirements. <br /> <br />C-2 <br /> <br /> <br />Local <br /> <br /> <br />Most of the innovative efforts to map, regulate and otherwise manage alluvial fans <br /> <br /> <br />ha ve occurred a t the local level. <br /> <br />Riverside County, California, has developed an alluvial fan methodology and <br /> <br /> <br />mapped alluvial fans in the Cabazon area. It has also adopted special regul- <br /> <br /> <br />ations reflecting flood velocities, erosive force and debris. <br /> <br /> <br />Los Angeles County, California has mapped alluvial fans and adopted a grading <br /> <br /> <br />code for these and other areas. <br />