FLOOD03149 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I I. INTRODUCTION Central City is a historic gold mining town in the Rocky Mountain eastern slopes located a~proximately 30 miles west of Denver, Colorado. (Refer to Exh i bit A.) Steep slopes and rugged mountai ns resulted in town development along and over gulches which thread through surrounding hills. Pipelines or rock flumes were constructed to convey storm runoff, over which the main business district of town was built. Inherent with development over natural drainageways are flooding problems. Over the years, the City of Central has had reports prepared and made improvements to help mitigate flooding. A brief history of floodplain management efforts is provided below. In an effort to protect property owners from the cost of flood damage, a Flood Hazard Boundary Map for Central City was prepared for the Federal Insurance Admin"istration (effective in 1974 and reproduced herein as Exhibit "B"), and Central City entered into the National Flood Insurance Program in 1986. Comparing Exhibits "A" and "B", it can be seen that a large portion of the business district was located within the flood hazard area. 1 In 1986, the City of Central requested the assistance of the Colorado Water Conservation Board (CWCB) to perform a hydrological and hydraulic study including mapping which would more closely identify flood limits and elevations that the City may better administrate a newly adopted floodplain ordinance. Thll study was performed, providing valuable floodplain information. Their study was used in preparing this report. (See Reference I in the Bibliography.) Frequently menaced by even the smallest of rainfall events, the next step taken by the City was to have a feasibility study performed which would provide guidance in improving facilities so that flood damage and sedimentation frequency and extent may be reduced. Accordingly, Hydrodynamics Incorporated was retained and prepared a report based on the CWCB study to identify possible improvements, benefits, and costs. (See Reference No.2 in the Bibliography.) However, City funds were limited, so proposed projects were minimized and only served to reduce major flooding related problems from a 2 to 3 year event to nearly a 15 year event. Even so, the City was unable to secure the estimated $519,800.00 required, and proposed improvements were not made. Sedimentation in streets during summer thundershowers still occurred, major flooding potential still existed, and the main business district remained in a flood hazard area. In an effort to reduce maintenance and limit flood damage, the City pursued steps to remove downtown from the 100-year floodplain and also reduce flood-related maintenance problems. Pursuant to this effort, Rocky Mountain Consultants was retained to analyze previous reports and estimate proposed costs and solutions to remove the downtown area from the 100-year floodplain and reduce maintenance costs. Based on previous reports, an estimate of $1,300,000.00 was made, along with a recommendation that it would be cost effective to have a more detailed study performed. Accordingly, RMC was then retained to perform a detailed