A Colorado Parks & Wildlife hydrologist estimated that the Cache la Poudre River’s peak flow early on Sept. 13 was about 11,000 cubic feet per second, about half the all-time record of 21,000 CFS recorded in the 1880s.
Aquatic research Scientist Eric Richer said that flood waters took out water measurement gauges at the mouth of the Poudre before a high-water mark could be recorded. From his preliminary data, Richer estimates the recent flood at about once in every 65-year event. He was in the process of confirming the CFS flows this morning using surveying equipment.
Data from the Colorado Division of Water Resources gauges at the mouth of the Poudre Canyon show the gauge failing at about 11 p.m. on Sept. 12, near the 6,000 CFS mark. Measurements were restored late the next night, with the river running in the 6,000 CFS range. The gauge is located 1/2 mile downstream from headgate of Poudre Valley Canal and about 1.2 miles upstream from Lewistone Creek.
U.S. Geological Survey water flow measurement gauges in Fort Collins near East Lincoln and North College registered the Cache la Poudre’s peak water level at 11-feet high and at about 9,000 CFS on late Sept. 13 into early Sept. 14.
Other high-water events include a flood in 1903 that was recorded at about 12,000 CFS and the recent 1997 flood, where the river flowed at about 3,000 CFS. Normal river flow for September, based on about 100 years of observation, is between 100 and 300 CFS. A cubic foot of water equals about 7.5 gallons.
Final numbers on the Poudre River flows will be released later this month.