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6 - FUTURE FLOODS - Flooded Areas Flood Frequency and Discharge Floods of the same and greater magnitude as those that have oc- curred in the past will occur in the future. With development in the basin, flooding will occur more frequently. The dis- charges reported on Figures 3 and 4 for the 2-, 10- and 100-year flood frequencies represent the relative extent and impact of each flood event. The discharge information is usable not only for flood plain regulation but also for planning, engineering and flood plain improvement. The 100-year flood plain limits and water surface profiles are shown on the attached Flood Hazard Area Delineation Maps, Sheets 3 through 20. The computed 100-year flood elevations at each reference point are tabulated in Tables 5 and 6. A descriptiQn of the extent of flooding is discussed in the following paragraphs. Goldsmith Gulch - The flood plain limits and flood profiles for Goldsmith Gulch are shown on the Flood Hazard Area Delineation Maps, Sheets 3 through 17. The 100-year flood event, which can be expected to occur at any time in a given area, based upon recorded historical precipitation and other valid data, has a one percent chance of being equalled or exceeded during anyone year. The 100-year flood event pro- vides a lower risk of failure than the 10-year or 50-year flood event, when considering structural flood plain improvements. The 100-year flood event is considered by the Urban Drainage and Flood Control District, the Colorado Water Conservation Board, and the Federal Insurance Administration as the flood magnitude for which flood plains should be designated for regulatory and im- provement purposes. In Colorado, the 100-year flood plain rep- resents an area of state interest as defined in H.B. 1041. In the reach from Cherry Creek to Mexico Avenue the 100-year flood plain encompasses Cook Park. The park has no damageable development as the parking lot and sports complex buildings are raised above the 100-year flood plain. The western edge of the flood plain is de- fined by the houses along the west side of Monaco. The houses fronting on the street are out of the flood plain with the exception of the houses north of Floyd Avenue which are in the combined flood plain of Cherry Creek and Goldsmith Gulch. This area is shown on Drawings G-l and G-2. Figure 5 provides a view of the Mexico Avenue Crossing. The 2- and 10-year recurrence flood magnitudes have also been cal- culated at various design points along each creek. These flood magnitudes represent events which can cause damage but would not inundate the area characteristic of a 100-year event. The peak flows for these events should be used in the planning and engi- neering of improvements where the higher risk of failure or damage is economically feasible and the hazard to life and property is lower or non-existent. The reach from Mexico to Evans represents one of the major problem areas on Goldsmith Gulch. The channel is very narrow and constricted and as a consequence, the flooding of surrounding properties is extensive. Major problems include inadequate crossing structures and small channels with sharp bends such as the 900 bend in the 12' x 7' narrow, concrete channel around the tennis court near Monaco and Jewell. The section of channel between Monaco and Mexico is well defined although it is inadequate to carry the 100-year flood. The houses on both sides of the channel through this reach will be subject to flooding during the 100-year storm. Also, there will be flood waters on Monaco Boulevard from Cherry Creek upstream to Iliff. Flood depths may be 1 to 1.5 feet. A view of the Jewell Avenue crossing is provided in Figure 6. Flood magnitudes greater than the 100-year flood magnitude can and will occur. Land improvement adjacent to the 100-year flood plain limit should consider the chance for possible flood damage.