Laserfiche WebLink
<br /> Are CWCB regional regression Hydrologic . ' Hydraulic <br />, Type of development equations applicable to the stream req uirements , requirements <br />; proposal in community of interest? for developer for developer <br />Limited development Yes Approximate Approximate <br />Limited development No Detailed Approximate <br />Significant development Yes Detailed Detailed <br />Significant development No Detailed Detailed <br /> <br />Table 2 <br />, CWCB procedure for regulating approximate Zone A floodplains <br /> <br />Table 2 (continued) <br />Definitions for regulating approximate Zone A floodplains <br /> <br />Limited Development: Development involving parf,::s, open space, golf courses, agriculture, bridges and <br />culverts that serve a single farm/home/cabin, pole bains, and individual single family structures. <br />Significant Development: All development that does not fall under one of the categories listed under <br />the Limited Development definition. A special cas~ of significant development is a development that <br />involves more than 5 acres or more than 50 units (,vhichever is more restrictive). This special case is <br />important because federal regulations require that a detailed study be submitted to the communily by the <br />developer, Failure of the community to require a detailed study will result in a violation of the National <br />Flood Insurance Program, which can have negative impacts on floodplain property owners within the <br />community. <br />Approximate hydrology: I OO-year peak flow value$ estimated for the hydrologic point of interest using <br />CWCB "Guidelines" regression equations or other acceptable approximate hydrologic method approved <br />by the CWCB. <br />Detailed hydrology: 100-year (and 10-, 50-, and 500-year when applicable) peak flow values computed <br />for the hydrologic point of interest using an acceptable detailed methodology, other than the <br />"Guidelines", such as an at-site stream gage analysis, a regional stream gage analysis, or a rainfall- <br />runoff model. <br />Approximate hydraulics: Water surface elevations or flow depths computed for the location or reach of <br />interest using normal depth flow calculations (i.e. Manning's equation/slope-area method), Computer <br />programs such as QUlCK-2 and FlowMaster are excellent tools for this purpose, <br />Detailed hydraulics: Water surface elevations (base flood elevations) computed for the stream reach of <br />interest using a step-backwater computer model, or other acceptable one-dimensional or two dimensional <br />computer model, such as HEC-2 or HEC-RAS. <br /> <br />;and <br /> <br />WHEREAS, the approximate floodplain information on said floodplain maps with said new <br />report for stream reaches in Gilpin County as listed in Table I meet the requirements for <br />approximate floodplain information as listed in the Board's "Rules and Regulations for the <br />Designation and Approval of Floodplains and of Storm or Floodwater Runoff Channels in <br /> <br />4 <br />