FLOOD04092 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I Stormwater flooding can occur almost anywhere. While we are a semi-arid environment we can get a burst of rain that exceeds an inch in a one hour period. While the City maintains some storm water piping, this piping can be overcome by such a rain, causing flooding. Stormwater flooding generally occurs in low-lying areas or in routes going towards those areas. 3. Flood Hazard Data a. Sources of Water: 1. Gunnison River 2. Uncompahgre River 3. Rain water 4. Irrigation water. b. Depth of FloodinJ!: No flood hazard area can be considered safe. However, flooding over three feet is more hazardous. Areas subject to such depths should be identified by comparing base flood elevations with ground elevations. The areas most likely to exceed the three foot mark would be in the 100 floodplain on the FIRM maps. Areas of flooding one foot deep or so could occur almost anywhere. Co Velocities: Flood water velocities over 5 feet per second are most hazardous especially when combined with deep flooding. Since velocity data is often hard to obtain and it can include inaccuracies, the following rule of thumb for moving water should be used for planning purposes: 1) One foot deep - no vehicles should enter; and 2) three feet deep - no people should enter. Given Delta's topographic changes, higher velocity flows can be found in a number of areas. d. WarninR Time: Warning time of as little as 30 minutes can be enough to implement property protection measures. State, county or local emergency managers should be contacted to obtain these times so they may be incorporated into a plan. Noaa Weather Radio "All Hazard Alert System" is available to City of Delta residents and can provide extended warning times. e. Repetitive Loss Areas: Previous loss areas are predominant along the river corridor. Repetitive losses account for 1/3 of all NFIP flood insurance claims. Areas of repetitive loss should be identified. Such information can be obtained from FEMA's Regional Offices in Denver at (303) 235-4830. 4. Problem Assessment a. Land Use and BuildinRs: Weare using the hundred year floodplain as our basis for identifying the buildings and property at risk from flooding in non-dam break events. There are approximately 143 properties that are in part or in whole in the 100 year floodplain. There are far fewer buildings actually in the floodplain. At last count we counted 125 Homes. Approximately 103 of these are mobile homes with the majority in the two mobile home and Rv parks at Hwy 50 and the River. The rest are stick-built home above the Hwy 50 bridge on the Gunnison and stick-built homes along the Uncompahgre.