FLOOD11039 - Laserfiche WebLink

Home Browse Search

temperature ranges of 500F are not uncommon in the winter or the summer. Average annual precipitation is 23 inches. Approximately two-thirds of this amount occurs as snowfall during the winter (Reference 1). 2.3 Principal Flood Problems High peak flows on the Fraser River and Vasquez Creek result, without exception, from snowmelt occurring from May to July. Discussions with long-term residents indicate that no floods resulting in widescale property damage have occurred in the Winter Park area. However, the June 27, 1983, peak flow, the second highest flow of record, resulted in damage to bridge abutments on the Fraser River bridges at Winter Park Drive and High Country Drive, to the road embankment at Ski ldlewild, and to the culvert at the Arapahoe Road crossing of V asquez Creek. High water caused residents to sandbag the channel near the Hi Country condominium developments and to protect the channel bank at the Winter Haven Lodge and the Vasquez Road crossing on Vasquez Creek. One wooden bridge on the Fraser River near Maryvale was destroyed. Photographs of the areas mentioned are shown in Figures I through 8. The 1983 peak flow of618 cubic feet per second (cfs) recorded at U.S. Geological Survey (USGS) Gage No. 09024000 on the Fraser River was approximately a 50-year flood. Historically, the annual flows have generally been confined within the channel, with minor exceptions in the Beaver and Maryvale areas on the Fraser River. Blockage of culverts or bridges caused by debris has not been a problem identified by the Town of Winter Park, nor has ice jamming been a problem in the past. The areas that are most constrictive have been identified by the town as the Ski ldlewild culverts crossing the Fraser River and the culvert at the Arapahoe Road crossing of Vasquez Creek. The town has replaced the Arapahoe Road culvert with a properly sized culvert. This new culvert was included in the analysis for the May 1984 study. The Ski ldlewild Road is privately owned, and the town has no jurisdiction over it. Several minor structures built across the Fraser River, such as footbridges and temporary bridges, were washed out during the 1983 flooding and have not been rebuilt. Such structures could block downstream culverts or bridges, which may aggravate flooding problems. The highest flow of record, at the time ofthe May 1984 study, on the Fraser River was 820 cfs recorded on June 13, 1918, at USGS Gage No. 09024000, which was greater than a 500-year event. 2.4 Flood Protection Measures The Town of Winter Park restricts building within 30 feet of the average high water line. The determination of this line is made by the U.s. Army Corps of Engineers (USACE) on a site-specific basis. There are no structures in the Fraser River basin specifically designed for flood protection. There are, however, several diversion structures and railroad and road embankments that affect flooding. Water is diverted from the Fraser River, Jim Creek, Vasquez Creek, and Little Vasquez Creek by the Denver Water Board. These diversions have been in operation since the 1930s. Total capacity of the diversion system is 750 cfs. Base flows for fish population maintenance are 10 cfs for the Fraser River and 8 cfs for Vasquez Creek (Reference 1). The effects ofthe diversions have not been included in the hydraulic analysis for this study. 5