FLOOD08354

• County: Boulder
• Community: Lafayette
• Stream Name: Coal Creek , Waneka Reservoir
• Basin: South Platte
• Title: Major Basinwide Planning
• Date: 12/1/1980
• Prepared For: Boulder County
• Prepared By: Camp Dresser & McKee
• Floodplain - Doc Type: Floodplain Report/Masterplan

I
I
I
I
I
I
I
I
I
I
I
I
I
I
,
I
I
I
.

TABLE OF CONTENTS

LIST OF FIGURES

Chapter Subject

Page

I SUMMAR Y
Description of Study Area
Scope
Selection of Alternative Plan
Recommended Alternative
Basinwide Major Drainageway Improvements

1
2
3
4
5

Figure 1 Vicinity Map
Figure 2 Major Drainage Basins
Figure 3 10-Year and 100-Year Design Streamflows
Figure 4 Selected Storm Hydrographs
Figure 5 Potent i al 100-Year Flooded Area Map

II EXISTING DRAINAGE BASIN CONDITIONS

III HYDROLOGY
Rainfall
Soils and Infiltration
Existing and Future Condition Hydrology

8

12
12
15

LIST OF TABLES

IV FLOODPLAINS AND AREAS OF POTENTIAL LOCAL FLOODING
Flood Frequency
Flood Profil es
Flooding Potential
Floodplain Management

16
16
18
19

Table 1

Summary of Projected Costs
Major Sub-basin Characteristics

Table 2

V 8ASIS OF DESIGN
Open Channels
Underground Conduits and Street Crossings
Construction Cost Estimate

Table 3

Summary of Sub-basin Hydrology

21
22
23

Table 4

5-Minute Increment, 2-Hour Duration Design Storms

Table 5

Summary of Unit Costs

VI CONSTRUCTION PROGRAM
Stage 1
Stage 2
Stage 3
Others

26
28
28
29

lER\~ f!. n,,;'
~ ,l.~ '. ...1 I" ',J '._'
. "Ii ~~, k'~ i{ ( ',.
~U~~ta1~ u

[ ~ {\ rc:':::~ '~;':' J ::,:; ~ c;
c.,':I _1. i:<i ",..,,"1..',"'J ,t.t n~
lij,.. .. 1IJ ~:..,....~"... o::~u

C~ ~ "-:,..~ ~". ~ ~
L~~; ~:-.- .:".-: C

'., :-~'-"

;"};1:q 2 n [: C-i^.~D
.: !,-" ~ L" -' : i: (':, '"
.J,,_ ""'i..iJ;o'i\:.l

References

.0 i. P

l~'~~' S>:",,:~"'
I;'....:.. .. :.;. ,
..... ......1 ...".._." ,~.....

Appendix A - Agency/Interested Party Contact

:'~2J3

Drawings

~r-i'''''f. 1'-, ~ '1 '.'
" ~.t'" ~- F ~ . F l,l.
<..' ~ I ivJr\.~._.

\.'
,,-c' ~,,- ~ ~

Profil es

FoIl owi ng
Page No.

1

Page No.

7
11

13
14
24