PROJ00279 - Laserfiche WebLink

Home Browse Search

J I I I I I I I I I I I I I I I I I I with large rain storms. Sedimentation for B-3 was estimated at 0.19 watershed- inches for the design life of 100 years. The watershed for Reservoir No. 2 is 4.33 square miles. At the rate utilized by the SCS, the sediment yield would be 44 acre-feet for a 100 year design life. The sediment yield for B-2 was estimated by the SCS at 0.28 watershed inches for. the 100 year design life. For Reservoir No.2 that would produce a yield of 65 acre-feet. This yield is expected to be greater than that experienced for Reservoir No. 2 as B-2 is located on Box Elder Creek which drains a large area with sparse vegetation and experiences continuous stream flows. Also, the reservoir has not experienced any significant siltation problems since being constructed in the late 1800's. It is our conclusion that a 40 to 50 acre-feet reduction of reservoir capacity over the next 100 years is a reasonable estimate for the type of basin Reservoir No. 2 is located in which is not a signif- icant reduction in total capacity. G. Riqht-Of-Wav. The right-of-way around the reservoir has been briefly reviewed to try to detect any apparent problems with the raising of the reservoir water level. A detailed surveyor legal breakdown has not been conducted. The highwater line for the normal pool of Gage Height 24 feet does fall within the boundary of land owned by The North Poudre Irrigation Company. North Poudre feels confident that the reservoir has been at Gage Height 24 feet for an large number of years and that all lands below that elevation belong to North Poudre. For the probable Maximum Flood, it would appear that the high water may not be within the property lines on the north end of the site. This can not be ascertained without a survey and breakdown of the four sections that the reservoir falls within. If the reservoir is raised to store to Gage Height 29 feet, a rough estimate indicates at least 75 acres of land may have to be purchased to contain the normal pool and a 100 year flood. Another area where right-of-way may need to be purchased is for the spillway. One of the proposed spillway locations, on the east side of the East Dam as shown on the plan in Appendix H, would require the purchase of 6 to 8 acres of easement. This would be required to route the spills into the natural drainage. Once the water is in the natural drainage channel, easement is not required. No other right-of-way problems were detected at this time. Only a detailed survey and plot of the legal descriptions would ascertain specific right-of-way problems and that level of investigation was not conducted at this stage of the project. V-6