FLOOD10389 ‎(2)‎

• Designation Number: 577
• County: Conejos
• Community: Manassa
• Stream Name: Conejos River
• Title: Floodplain Information Report - Manassa Colorado
• Date: 8/1/2004
• Prepared For: Manassa and CWCB
• Prepared By: Love and Associates
• Floodplain - Doc Type: Floodplain Report/Masterplan

I
I Table 1. Regional flood-frequency equations, Colorado
I [Q, discharge. in cubic feet per second; A, drainage area, in square miles; P, mean annual precipitation, in inches; S, mean drainage-basin slope, in foot per foot]
Recurrence interval, Standard error Average standard
in years Regression equation of the model, error of prediction,
in percent in percent
I Mountain region
2 Q = 11.0 (A) 0.663 (S + 1.0) 3.465 58.5 59.6
5 Q = 17.9 (A) 0.677 (S + 1.0) 2.739 47.7 48.6
I 10 Q = 23.0 (A) 0.685 (S + 1.0) 2.364 43.7 44.6
25 Q = 29.4 (A) 0.695 (S + 1.0) 2.004 41.4 42.3
50 Q = 34.5 (A) 0.700 (S + 1.0) 1.768 41.4 42.3
I 100 Q = 39.5 (A) 0.706 (S + 1.0) 1.577 42.4 43.4
200 Q = 44.6 (A) 0.710 (S + 1.0) 1.408 44.2 45.2
500 Q = 51.5 (A) 0.715 (S + 1.0) 1.209 47.5 48.6
I Rio Grande regi?n <.
2 Q = 0.03 (A) 0.979 (P) 1.615 77.7 82.6
5 Q = 0.12 (A) 0.940 (P) 1.384 64.0 67.9
10 Q = 0.25 (A) 0.914 (P) 1.277 58.2 89.1
I 25 Q = 0.52 (A) 0.884 (P) 1.117 53.4 56.8
50 Q = 0.81 (A) 0.864 (P) 1.121 51.2 54.5
100 Q = 1.19 (A) 0.846 (P) 1.074 49.9 53.3
I 200 Q = 1.67 (A) 0.828 (P) 1.036 49.5 52.9
500 Q = 2.48 (A) 0.808 (P) 0.995 50.0 53.6
Southwest region
I 2 Q = 28.7 (A) 0.699 85.0 87.3
5 Q = 50.5 (A) 0.693 74.1 76.1
10 Q = 66.0 (A) 0.697 71.4 73.4
25 Q = 86.3 (A) 0.704 71.2 73.4
I 50 Q = 102.0 (A) 0.709 72.8 75.0
100 Q= 118.4 (A)0.715 75.6 78.0
200 Q = 135.5 (A) 0.720 79.1 81.7
I 500 Q= 159.4 (A) 0.728 85.0 87.9
Northwest region
2 Q = 0.39 (A) 0.684 (P) 1.304 82.6 85.6
I 5 Q = 2.84 (A) 0.674 (P) 0.833 71.5 74.0
10 Q = 7.56 (A) 0.671 (P) 0.601 68.5 70.9
25 Q = 20.6 (A) 0.669 (P) 0.362 67.1 69.7
50 Q = 38.8 (A) 0.667 (P) 0.210 67.2 69.8
I 100 Q = 104.7 (A) 0.624 75.0 76.7
200 Q = 118.5 (A) 0.624 77.8 79.6
500 Q = 137.6 (A) 0.623 83.1 85.1
I Plains region
2 Q = 39.0 (A) 0.486 233.7 258.5
5 Q = 195.8 (A) 0.399 204.2 223.8
I 10 Q = 364.6 (A) 0.400 212.4 233.7
25 Q = 725.3 (A) 0.395 231.8 256.2
50 Q = 1116 (A) 0.392 249.5 278.3
100 Q = 1640 (A) 0.388 267.3 300.0
I 200 Q = 2324 (A) 0.385 284.5 321.3
500 Q = 3534 (A) 0.380 305.8 347.9
I ESTIMATING MAGNITUDE OF PEAK DISCHARGES 9
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