FLOOD02208

• Designation Number: 547
• County: Gilpin
• Community: Black Hawk
• Basin: South Platte
• Title: Draft Report - Reconstituition of 1979 Flood Peaks, North Clear Creek, Gregory Gulch, and Chase Gulch
• Date: 4/26/2001
• Designation Date: 5/1/2001
• Floodplain - Doc Type: Floodplain Report/Masterplan

INTRODUCTION
STUDY AREA
Figure 1 - Vicinity Map
BACKGROUND
HYDROLOGIC ANALYSIS
Figure 2 - "Soil Hydrologic Groups"
Figure 3 - "1979 Land Uses"
Figure 4 - "Basin (Catchments) Areas"
Table 1- "Preliminary Curve Number Calculations, Basins 1-10,
1979 Land Use"
Table 2 - "Summary of Time of Concentrations, Basins 1-10"
CALffiRATION
Table 3 - "Curve Numbers Adjustments for Calibration Basins
1-10,1979 Land Use"
RESULTS
Table 4 - "Comparison of 1979 Flood Peak Estimates to TR20
Model Estimates, 100-Year Event"
IMPACT OF RESERVOIR STORAGE ON FLOOD PEAKS
Figure 5 - "Chase Gulch Water Supply Reservoir Storage Above
Spillway" II
Figure 6 - "Dorothy Lee Detention Reservoir Eureka/Gregory Gulch" 12
Table 5 - "Flood Peaks for the 10-,50-, and 100-Year Events
At Selected Design Points Including Storage Effects
Of Detention Along Chase and Eureka/Gregory Gulches" 13
14
15

TABLE OF CONTENTS

CONCLUSION
REFERENCES
APPENDIX

Page No.
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. Type IA - Rainfall Distribution
. Type II - Rainfall Distribution
. Report Entitled, "Evaluation of Runoff Curve Numbers (CN) for North Clear
Creek, Gregory Gulch and Chase Gulch," Provided to CWCB to obtain direction
response.
. Telephone call record confirming Larry Lang response to request of report above.
. Estimation of Runoff Curve Numbers (CN) from Black Hawk Floodplain
Information Technical Addendum (BFITA)
. Table - "Time of Concentration - Basins"
. Table - "Time of Concentration - Reaches"
. "Spillway Discharge Curve - Chase Gulch Reservoir," (RMC, 1994)
. FHW A Culvert Analysis - HY -8 - Dorthy Lee Reservoir
. North Clear Creek 100-Year Event (TR20 model) Calibration - No. Reservoir
. Gregory and Chase Gulches - 100- Y ear Event (TR20 model) - Including
Reservoir
. Gregory and Chase Gulches - 100- Y ear Event (TR20 model) - Including
Reservoirs