Laserfiche WebLink
<br />000592 <br /> <br />2. Adverse Flood Impacts and Durability <br />The CWCB takes very seriously the flood safety aspects of RICDs, and will carefully <br />consider flood safety in reviewing the RICD application.. The CWCB recommends that <br />an applicant for an RICD demonstrate, through appropriate technical analyses, that the <br />proposed boating course is designed and will be (is) constructed in such a manner as to: <br />. Adequately pass all flows up to and including the lOO-year (l1o probablity) flood <br />flow without causing adverse impacts to upstream, downstream or adjacent <br />property owners. Verification of "no adverse impact" can be demonstrated <br />through the use of a CWCB approved step-backwater hydraulics model such as <br />HEC-RAS. 1 <br />. Adequately withstand stream forces for all flows up to and including the IOO-year <br />flood so that damage and failure of the boating course is avoided.2 <br /> <br />3. Liability <br />The CWCS assumes no responsibility for use or misuse of the boating course and is not <br />subject to liability for injuries or damages caused therefrom. CWCB approval of or <br />recommendation to endorse an applicant's proposed RICD water right in no way implies <br />that the CWCB accepts responsibility for final design, construction, operation, and <br />safety of the boating course. <br /> <br />1 As required by current federal regulations and state floodplain management rules (not new guidance <br />developed for the purposes of this document), the applicant is advised that the proposed boating facility <br />must be analyzed for flood impacts by modeling the "existing conditions- (pre-facility) scenario and the <br />ftproposed conditions- (with-facility) scenario. The hydroulic computer modeling must be performed by a <br />registered Professional Engineer (Colorado Registration) having expertise in surface water hydraulic <br />modeling. Impacts that should be analyzed include increases in water surface elevations for the range of <br />flows experienced at the proposed recreational facility, but especially the lOO-year flood event. <br />According to federal regulations. water surface elevations at the proposed RICD facility may not increase <br />at all (zero rise) in the event that the proposed recreational facility is within a stream reach having a <br />designated Floodway (the most hazardous portion within the lOO-year floodplain). For reaches that are <br />not within a designated Floodway, any increases in the lOO-year flood profile for the proposed RICD <br />facility (up to a tnaXimum of one foot or a lesser amount specified by local floodplain ordinances or codes, <br />whichever is more restrictive) must be documented. Proper notification of adverse impacts (increased <br />water surface elevations) must be provided to affected property owners and a Letter of Map Revision <br />(LOMR) should be obtained as required by FEMA for National Flood Insurance Program purposes. <br /> <br />zIt is recommended that the boating course consist of appropriate materials and installation to endure <br />velocities. shear stresses, other erosive conditions, sedimentation, and debris that would be experienced <br />during the range of expected flows and high flow (flood) conditions. For example, a boulder drop <br />structure should be constructed with material having suitable size, hardness, shape and gradation and <br />should be installed in such a manner that it is anchored into the stream bank and streambed to survive <br />long-term operation and flood events. Proper durability of the facility will assist the applicant in avoiding <br />costly repairs and maintenance, and may help to avoid possible abandonment of the RICD water right in <br />the future. <br /> <br />3 <br />