FLOOD07627

• Designation Number: 220
• County: Douglas
• Community: Unincorporated Douglas County
• Stream Name: Marcy Gulch
• Basin: South Platte
• Title: Flood Hazard Area Delineation - Marcy Gulch
• Date: 2/1/1983
• Designation Date: 3/1/1984
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Section

I.

II.

III.

IV.

V.

VI.

APPENDIX

TABLE OF CONTENTS

ABSTRAC~ .................................................

INTRODUCTION................................... ..........

A. Scooe of Work............................. ..........

B. Coordination........................................

C. Met hodo logy .........................................

DRAINAGE BASIN CHARACTERISTICS...........................

A. General.............................................

B. Marcy Gulch .........................................

C. Climatology and Flood History.......................

HYDROLOGI CANAL YS IS.. .. .. .. .. .. .. .. . .... .. .. .. .. .. .. . . .. .
HYDRAULI CANAL YS IS. . .. . . .. . . . . .. . . .. . .. . . .. . .. . . . . . . . .. . .
FLOOD HAZARD AREA DELINEATION ............................

A.
B.

Flood Frequency and Discharge
Flood Plain and Floodway Data

.......................

C. Flood Velocities and Erosion Potential..............

REFERENCES

...............................................

Flood Plain and Floodway Reference Data
Sample Flood Hydrographs
Peak Flow Profiles

Flood Hazard Area Delineation Drawings, Sheets 1 through 12

LIST OF TABLES

Page

1
1-2
1
1

TABLE 1 - DESIGN 100-YEAR RAINFALL PATTERN.........................
TABLE 2 - WATERSHED AND HYDROGRAPH PARAMETERS AND CALCULATED PEAK

FLOW RATES ...............................................

TABLE 2A- PEAK FLOW RATES

..........................................

2

TABLE 3 - FLOOD PLAIN AND FLOODWAY REFERENCE DATA (without
tentative culvert-type road crossings), sheets A - F.....

2-3
2
2
3
3-8

TABLE 4 - FLOOD PLAIN AND FLOODWAY REFERENCE DATA (backwater
at tentative culvert-type road crossings) sheet A........

LI ST OF FIGURES

FIGURE 1 - RELATIONSHIP BETWEEN Ct AND % IMPERVIOUS ...............
FIGURE 2 - RELATIONSHIP BETWEEN PEAKING PARAMETER (P) AND
% IMPERVIOUS...........................................

FIGURE 3 - SLOPE CORRECTION FOR NATURAL DRAINAGEWAYS ..............
FIGURE 4 - RELATIONSHIP BETWEEN HOUSING DENSITY AND % IMPERVIOUS
FIGURE 5 - SAMPLE FLOOD HYDROGRAPHS (at stations

40+40 and 40+00) .......................................

FIGURE 6 - SAMPLE FLOOD HYDROGRAPHS (at stations
100+0090+00 and 167+85) ...............................

FIGURE 7 - SAMPLE FLOOD HYDROGRAPHS (at stations

233+ 13 and 276+40 ......................................

FIGURE 8 - PEAK FLOW PROFILE (Reach 1 from station
40+40 to 180+00) .......................................

FIGURE 9 - PEAK FLOW PROFILE (Reach 1 from station
180+00 to stat ion 320+00) ..............................

FIGURE 10 - PEAK FLOW PROFILE (Reaches 1 thru 4 from station
320+00 to station 617+92) ..............................

9
10-12
10
10
12
12

Page
4

8
8

Appendix

Appendix

5

5

6
7

Appendix

Appendix

Appendix

Appendix

Appendix

Appendix

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