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. . . Table 1 Estimated loo-year peak flows for Rockvale Stream Location Drainal!e Area (SQ mi) loo-year Peak Flow (cfs) Oak Creek at Downstream Town Limit 62.2 15,000 South Oak Creek at Downstream Town Limit 7.0 3,750 A procedure for determining hydrology information for approximate floodplains of lakes, ponds, and local drainages has not been established. The hydrologic methodology developed in the Guidelines is appropriate for designation and approval of approximate floodplain information and for use in simple floodplain analyses for development such as open space, agriculture, farm bridges, pole barns, and individual single residential structures. The methodology is not appropriate for development involving residential subdivisions greater than 50 lots or occurring on sites greater than 5 acres, commercial construction, industrial construction, construction of public transportation facilities, or construction of flood control facilities. The Town of Rockvale should regulate the approximate floodplains on a case-by-case basis subject to a detailed hydrologic and hydraulic analysis. A detailed floodplain analysis may be required in certain cases and should be performed by a professional engineer and submitted by the developer or development proponent. An approximate floodplain analysis can be submitted by a developer or development proponent, for the cases listed above, in accordance with the determinations of the Colorado Water Conservation Board regarding the applicability of the Guidelines. Hvdraulic Analvsis The hydraulic analysis for the preparation of the FIRM likely consisted of interpretation of USGS quadrangle mapping by HUD's engineering consultant, along with telephone discussions with town officials, The telephone discussions addressed any historic flood problems which may have occurred in Rockvale. FEMA did perform and did not have the benefit of any detailed hydrologic and hydraulic analyses for the preparation of the FIRM. A copy of the FIRM for Rockvale is included in the Appendix at the end of this report. Future hydraulic analyses for determining 100- year water surface elevations for approximate floodplains may be computed using FEMA's Quick- 2 computer program, the Corps of Engineers' HEC-2 computer program, or other acceptable hydraulic methods.