FLOOD07708 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I FLOOD HAZARD AREA DELINEATION, BULLHEAD GULCH AND TRIDUTARIES LAFA YETfE, LOUISVILLE, AND BOULDER COUNTY "..,to establish, regulate, restrict, and limit such uses on or along any storm or floodwater runoff channel or basin, as such storm or floodwater runoff or basin has been designated and approved by the Colorado Water Conservation Board, in order to lessen or avoid the hazards to persons and damage to property resulting from the accumulation of storm or floodwaters..." as stated in Section 30-28-111 for the county governments and Section 31-23-301 for municipal governments of the Colorado Revised Statutes 1973, 1.0 INTRODUCTION The Urban Drainage and Flood Control District (UDFCD), City of Lafayette, and City of Louisville have jointly sponsored the Flood Hazard Area Delineation study for Bullhead Gulch and Tributaries. Recent and proposed annexation by Lafayette within this 9.0 square mile watershed has created a need for this study, This report contains hydrologic and hydraulic computations, used in the development of 1oo-year floodplain delineations, 10- and 100-year water surface profiles, and one-foot rise and one-half-foot rise floodway data for Bullhead Gulch, Prince Tributary, and Indian Peaks Tributary, Upon acceptance of this study by the UDFCD and the designation and approval of this study by the CWCB, the areas described as being inundated by the loo-year flood (Intermediate Regional Flood) can be designated as flood hazard areas and their use regulated accordingly. It should be noted that the terms "Intermediate Regional Flood," "loo-year Flood," and "one percent flood" can be used interchangeably as they all define the same type of flood event. 1.1 AUTIIORIZATION 1.2 PURPOSE AND SCOPE This project was authorized by the UDFCD. UDFCD has the power to enact District-wide floodplain regulations. At present, the District makes floodplain information and mapping available for local agencies to adopt and administer their own floodplain regulations with the assistance of the District. "...to designate and approve storm or floodway runoff channels or basins, and to make such designations available to legislative bodies of cities and incorporated towns; to county planning commissions; and to boards of adjustment of cities; incorporated towns; and counties of this state..," as stated in section 37-60-106(1)(c) of the Colorado Revised Statutes 1973. This study consists of a floodplain analysis of Bullhead Gulch, Prince Tributary, and Indian Peaks Tributary. The purpose of this report is to provide local officials with a guide for floodplain management so that flood hazards and environmental problems can be controlled, The 1oo-year event is the regulatory flood as identified by the UDFCD, the CWCB, the Federal Emergency Management Agency (FEMA), the City of Lafayette, the City of Louisville and Boulder County. The information in this report does not imply any action by UDFCD or the State of Colorado to regulate use of floodplains, UDFCD has the authority to regulate floodplains, but currently has chosen to leave this responsibility with local governments. The Colorado Water Conservation Board (CWCB) has the power and duty The cities, incorporated towns and counties within the study area may provide zoning regulations... The 1oo-year floodplain was delineated based on future developed basin conditions for each of the three drainageways analyzed in this study. Both floodplain maps and flood profiles were prepared, In addition, floodways were identified. The floodway is a high hazard area characterized by deep water and high velocity flows during flood events and should remain free FLOOD HAZARD AREA DELlNEA nON BULLHEAD GULCH AND TIUBUTARIES FINAL 713119t 1