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<br /> <br />CHAPTER 2 <br />CWCB PRINCIPLES <br /> <br />SECTION 2 <br />CWCB OPERATING <br />PRINCIPLES <br /> <br />COLORADO <br />FLOODPLAIN AND STORMWATER CRITERIA MANUAL <br /> <br />. Open Channels <br />. Bridges and Culverts <br />. Dams and Reservoirs <br />. Levees <br />. Detention Basins <br />. Drop Structures <br /> <br />OPERATING PRINCIPLE <br /> <br />THE CWCB RECOMMENDS THAT GOVERNMENT ENTITIES IN COLORADO <br />ADOPT THE DESIGN STANDARDS PRESENTED IN THE STATEWIDE MANUAL <br />FOR HYDRAULIC STRUCTURES. THE CRITERIA PRESENTED IN THE <br />STATEWIDE MANUAL ARE CONSIDERED TO BE MINIMUM STANDARDS. <br />HOWEVER, GOVERNMENT ENTITIES MAY ADOPT HIGHER DESIGN <br />STANDARDS IF THEY SO DESIRE. <br /> <br />IT IS RECOMMENDED THAT DESIGN AND CONSTRUCTION OF HYDRAULIC <br />STRUCTURES THAT ARE CONSIDERED FOR FULL OR PARTIAL FUNDING BY <br />THE CWCB BE PREPARED IN ACCORDANCE WITH THE GUIDELINES <br />PRESENTED IN THE STATEWIDE MANUAL. THE CONSTRUCTION OF NEW OR <br />MODIFIED HYDRAULIC STRUCTURES SHOULD NOT ADVERSELY IMPACT <br />ADJACENT PROPERTIES WITHOUT DUE PROCESS AS REQUIRED BY FEMA <br />REGULATIONS AND CWCB RULES AND REGULATIONS. <br /> <br />2.6 HYDROLOGY <br /> <br />Hydrologic analysis is performed to determine peak flow rates and/or hydrographs for <br />various selected storm frequencies based on a scientific analysis of the physical <br />hydrologic process of streams, channels, or basins. The estimated flow rates are <br />used to perform hydraulic analysis of existing or proposed drainageways, delineate <br />flood hazard areas, and design drainage structures. <br /> <br />There are many different flow estimation analysis methods and techniques available. <br />However, not all of the methods can be effectively utilized in Colorado. Some <br />methods are not applicable for the hydrologic conditions that exist in Colorado, and <br />other methods cannot be utilized easily or accurately due to the lack of measured <br />data Also, the computed flow estimates may vary considerably depending on the <br />analysis methods utilized for a given watershed. Therefore, it is necessary to define <br />minimum standards for hydrologic analysis in order to promote accuracy and <br />consistency in the computed flow rates. <br /> <br />OPERATING PRINCIPLE <br /> <br />THE CWCB OPERATING PRINCIPLE IS TO PRESENT HYDROLOGIC METHODS <br />AND MODELS THAT CAN BE USED TO PRODUCE REASONABLE PEAK FLOW <br />RATES AND HYDROGRAPHS FOR USE IN FLOOD-RELATED STUDIES AND <br />PROJECTS ALONG DRAINAGEWAYS WITHIN THE STATE. <br /> <br />IT IS RECOMMENDED THAT THE FLOW RATES, FOR THE PURPOSE OF <br />FLOODPLAIN DELINEATIONS, BE CALCULATED IN ACCORDANCE WITH THE <br />HYDROLOGY CRITERIA PRESENTED IN THE STATEWIDE MANUAL OR BY <br /> <br />CWCB OPERATING <br />PRINCIPLES <br /> <br />APRIL 2004 <br /> <br />CH2-206 <br />