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The Grand Mesa study also eliminated the very light prec~p~- tation periods from the data base. In doing so, it was found that 11 percent of the total precipitation fell at a rate of less than 0.01 inch per hour (compared to 5.5 percent in Arizona). Elimination of these very light rates in Colorado amounted to 56 percent of the total hours (compared to 32 percent in the Arizona data-set) suggesting that even more hours with light precipitation rates are common in Colorado. 3.2.5 Dailv Precipitation Distribution The cumulative frequencies for daily precipitation totals are shown in Figure 3.2 Precipitation of 0.01 inch or more was measured on 170 gauge-days. This represented about 36 percent of all the days in the total storm periods. The figure shows that half of the 170 days had amounts below 0.15 inch and contributed less than 10 percent of the total precipi- tation (54.0 inches). The similar analysis for the Grand Mesa found the exact same results. In Arizona, half the total precipitation fell on only 10 percent of the days (which had totals of 0.70 inches or more). In Colorado, the corresponding figures were that half the total precipitation fell on 14 percent of the days (which had totals of 0.60 inches or more). Furthermore, in Arizona there were 9 days (5 percent) with totals greater than 0.99 inch (largest amount was 3.49 inch) which contributed about one-third of the total precipitation. The comparable numbers from Colorado were 6 days (3 percent) with totals greater than 0.99 inch (largest amount was 2.03 inch) which contributed one-fifth of the total accumulation. Super et ale (1986) concluded there was obviously a limited number of large storms on the Grand Mesa which were very important to the total precipitation while the very frequent days with 3-35 I I I I I I I I I I I I I I I I I I I