Laserfiche WebLink
<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />INTRODUCTION <br /> <br />The report, "Flood Plain Information, Breckenridge, Colorado" <br />presents data on flood hazards along the Blue River and its <br />tributaries in the vicinity of Breckenridge, Colorado. The <br />report defines the flood plain of the Blue River through the <br />town of Breckenridge and presents discharges for the 10-year, <br />25-year, Intermediate Regional Flood, and Standard Project <br />Flood at key points downstream from the town on the river. It <br />also presents the same information for the principal tribu- <br />taries in and near the town; French, Illinois, Lehman and Saw- <br />mill Gulches. Plate 1 in a pocket at the back of this report <br />is a map of the area. The purpose of this addendum is to <br />provide basic backup material used in the Breckenridge flood <br />plain report. The addendum contains various sample computer <br />prinouts and other data relating to the hydrologic and hydraulic <br />determinations. <br /> <br />The secondary purpose of this addendum is to provide guidance <br />to the town of Breckenridge and Summit County for use in their <br />planning efforts. - Specific recommendations are contained in <br />this addendum relating to the capacities of the existing bridge <br />and culverts crossing the Blue River, as well as recon~enda- <br />tions for future crossing structure capacities and channel <br />improvements. <br /> <br />The basis for recommendations and other planning information is <br />the Intermediate Regional Flood (IRF), or the 100-year flood. <br />This flood has a 1% probability of being equalled or exceeded <br />during anyone year. The Intermediate Regional Flood is used <br />by the Flood Insurance Administration and is generally accepted <br />as the design flood for flood protection in the United States. <br />It must be recognized, however, that floods of greater magnitude <br />may occur. For this reason, the Standard Project Flood has also <br />been delineated on. the flood plain maps. The runoff from a <br />Standard Project Flood is that runoff generated by a severe <br />combinat~on of meteorological conditions reasonably character- <br />istic of the hydrologic region, excluding extremely rare com- <br />binations. The Standard Project Flood (SPF) as used in this <br />report is generally considered as having a recurrence interval <br />of approximately once every 500 years. The Standard Project <br />Flood is not the largest flood that can occur in the study area. <br />For example, the design flow in the investigation for the safety <br />of a high hazard darn is that flow derived from the Probable <br />Maximum Storm. This storm is characteristic for any given region <br />and is dependent on a combination of physical and meteorological <br /> <br />~ Leonard Rice Consulting Water Engineers, Inc. <br />