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rescued. Only one life was lost; this was due, in part, to the flood's slow onset. In the valley downstream from Boulder, the flood plain was reported to have been inundated to an average width of approximately one mile for several days. Agricultural damages included loss of 1 ivestock, crops, pastures, fences, roads, and deposition of sand and silt on flood plain lands. In addition, considerable crop losses were suffered on lands outside the flood plain which were dependent on irrigation diversions from Boulder Creek. FLOOD OF 1-2 JUNE 1914 Heavy rains in the mountains that hastened the melting of a deep snowpack estimated at 50 percent above normal produced what news- paper accounts called, "the worst flood on Boulder Creek following the 1894 flood". Boulder's water supply system and the Boulder County farm were severely damaged. Numerous roads and bridges in the mountains were also damaged or destroyed. FLOOD OF 2-7 JUNE 1921 Little is known of this flood except that it produced the highest peak discharge ever recorded at the U.S. Geological Survey Orodell gage located about three miles upstream from Boulder and one mile upstream from Fourmile Creek. The Orodell gage has been continuously operated since 1916. A discharge of 2,500 c.f.s. was recorded on 6 June 1921. Rainfall totaled 3.36 inches at Boulder through the period of 2-7 June 1921. 28 FLOOD OF 4-8 MAY 1969 The flood of May 1969 resulted from a general storm of long dura- tion. Precipitation consisting of both rain and snow was heaviest in the mountains. In the Boulder and South Boulder Creek basins, the rainfall continued at a moderate rate for nearly four days. Total precipitation for the storm amounted to 7.60 inches at Boulder and 9.34 inches at the Boulder Hydroelectric Plant located about three miles up the canyon from Boulder. Peak flooding at Boulder occurred on 7 May 1969. Estimates of discharge at the Orodell gage indicate a peak of 1,220 cf.s. The discharge near Broadway in Boulder was estimated to be between 2,500 and 3,000 c.f.s. In- stances of erosion damage to bridges and streets, trees, and agricultural lands were recorded. Large areas were flooded downstream from Boulder. I I I I I I I I I I I I I I I I I I I B. HISTORY OF PROPOSED FLOOD CONTROL EVALUATIONS Previous studies are summarized in Table IV-I. In 1910, Federick L. Olmsted Jr, a noted professor of landscape architecture, prepared a report for the Boulder City Improvement Association entitled "The Improvement of Boulder, Colorado". In this report he noted, "The principal water in Boulder is Boulder Creek, and its principle function, from which there is no escaping, is to carry off the storm water which runs into it from the terri- tory which it drains. If, lulled by the security of a few seasons of small storms, the community permits the channel to be encroached upon, it will inevitably pay the price in destructive flood.".