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<br />CHANGES ARE MADE IN DETERMINATIONS OF BASE FLOOD ELEVATIONS FOR THE
<br />UNINCORPORATED AREAS OF BOULDER COUNTY, COLORADO, UNDER THE NATIONAL
<br />FLOOD INSURANCE PROGRAM
<br />
<br />On June 2, 1995, the Federal Emergency Management Agency identified Special Flood Hazard Areas
<br />(SFHAs) in the unincorporated areas of Boulder County, Colorado, through issuance of a Flood Insurance
<br />Rate Map (FIRM), The Federal Insurance and Mitigation Administration has determined that
<br />modification of the elevations of the flood having a 1- percent chance of being equaled or exceeded in any
<br />given year (base flood) for certain locations in this community is appropriate, The modified Base Flood
<br />Elevations (BFEs) revise the FIRM for the community,
<br />
<br />The changes are being made pursuant to Section 206 of the Flood Disaster Protection Act of 1973 (Public
<br />Law 93-234) and are in accordance with the National Flood Insurance Act of 1968, as amended
<br />(Title XIII of the Housing and Urban Development Act of 1968, Public Law 90-448), 42 US,c.
<br />4001-4128, and 44 CFRPart 65,
<br />
<br />A hydraulic analysis was performed to incorporate updated topographic information for Dry Creek No, 1
<br />and Clover Basin Tributary; realignment and channelization along Dry Creek No, 1 from approximately
<br />1,450 feet downstream to just downstream of a private road (renamed Grandview Meadows Drive);
<br />construction of a new bicycle path bridge across Dry Creek No, 1 approximately 800 feet downstream of
<br />Grandview Meadows Drive; replacement of an existing culvert under the Grandview Meadows Drive
<br />crossing of ~ Creek No, 1 with an 11-foot by 10-foot concrete box culvert and a 9-foot by 8-foot
<br />concrete box culvert; construction of a flood-detention basin along Dry Creek No, 1 approximately
<br />600 feet upstream of Grandview Meadows Drive; and channelization along Clover Basin Tributary from
<br />just upstream to approximately 400 feet upstream of its confluence with Dry Creek No, L For Dry Creek
<br />No, 1, this has resulted in the establishment of a regulatory floodway, increases and decreases in SFHA
<br />width, and increased BFEs from approximately 1,650 feet upstream to approximately 4,000 feet upstream
<br />of Grandview Meadows Drive, For Clover Basin Tributary, this has resulted in the establishment of a
<br />regulatory floodway fromjust upstream to approximately 300 feet upstream of its confluence with Dry
<br />Creek No, 1, and a decrease in SFHA width and decreased BFEs from just upstream to approximately
<br />1,600 feet upstream of its confluence with Dry Creek No, 1, The aforementioned channelized portions of
<br />Dry Creek No, 1 and Clover Basin Tributary contain the base flood, The table below indicates existing
<br />and modified BFEs for selected locations along the affected lengths of the floodingsource(s) cited above,
<br />
<br />Location
<br />
<br />Existing BFE
<br />(feet) *
<br />
<br />Modified BFE
<br />(feet) *
<br />
<br />Dry Creek No, 1:
<br />Approximately 1,700 feet upstream of
<br />Grandview Meadows Drive
<br />Approximately 4,200 feet upstream of
<br />Grandview Meadows Drive
<br />
<br />5,034
<br />
<br />5,036
<br />
<br />5,039
<br />
<br />5,041
<br />
<br />Clover Basin Tributary:
<br />Approximately 260 feet upstream of confluence
<br />with Dry Creek No, 1
<br />
<br />5,040
<br />
<br />5,039
<br />
<br />*National Geodetic Vertical Datum, rounded to nearest whole foot
<br />
<br />Under the above-mentioned Acts of 1968 and 1973, the Federal Insurance and Mitigation Administration
<br />must develop criteria for floodplain management To participate in the National Flood Insurance Program
<br />
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