FLOOD10311 ‎(2)‎

• County: Rio Grande
• Community: South Fork
• Stream Name: Willow Creek Watershed
• Basin: Rio Grande
• Title: Hydrologic Analysis Willow Creek
• Date: 3/27/2006
• Floodplain - Doc Type: Floodplain Report/Masterplan

Appendix 2. HEC-HMS model parameters for A. pre-bum conditions; and B. post-bum
conditions.

A.

Subbasin Drainage Pre.burn Initial Subbasin Drainage Storage SCS lag SCS lag
name area runolT abstraction length basin time time
(mi2) curve (in) (ft) slope (min) (hrs)
number (ftlft)
Willow 1 9.993 70.87 0.82 40760 0.202 4.11 108 1.8
Willow 2 1.182 66.17 1.02 14970 0.290 5.11 43.8 0.73
Willow 3 1.260 66.22 1.02 15760 0.215 5.10 55.2 0.92
Willow 4 1.892 64.37 1.11 16200 0.271 5.53 52.8 0.88
Willow 5 1.604 65.48 1.05 20550 0.230 5.27 67.2 1.1
Willow 6 1.790 66.53 1.01 25400 0.232 5.03 76.8 1.3
Willow 6a' 0.89 66.53 1.01 76.8 1.3
Willow 6b' 0.60 66.53 1.01 76.8 1.3
Willow 6c' 0.30 66.53 1.01 76.8 1.3

'fraction of subbasin 6, to better represent inflows in hydrologic and hydraulic model

B.

Subbasin Drainage Post. Initial Subbasin Drainage Storage SCS lag SCS lag
name area burn abstraction length basin time time
(mi2) runoff (in) (ft) slope (min) (hrs)
curve (ftlft)
number
Willow I 9.993 70.87 0.82 40760 0.202 4.11 108 1.8
Willow 2 1.182 69.85 0.86 14970 0.290 4.32 41.4 0.69
Willow 3 1.260 71.47 0.80 15760 0.215 3.99 48.0 0.80
Willow 4 1.892 91.18 0.19 16200 0.271 0.97 22.8 0.38
Willow 5 1.604 70.4 0.84 20550 0.230 4.20 58.8 0.98
Willow 6 1.790 79.2 0.53 25400 0.232 2.63 66.0 1.10
Willow 6a' 0.89 79.2 0.53 66.0 1.10
Willow 6b' 0.60 79.2 0.53 66.0 1.10
Willow 6c' 0.30 79.2 0.53 66.0 1.10

'fraction of subbasin 6. to better represent inflows in hydrologic and hydraulic model