FLOOD06904

• County: Larimer
• Basin: South Platte
• Title: Hydrology, Geomorphology, and Dam-Break Modeling of the July 15, 1982 Lawn Lake Dam and Cascade Lake Dam Failures, Larimer County
• Date: 1/1/1986
• Prepared For: Larimer County
• Prepared By: USGS
• Floodplain - Doc Type: Flood Documentation Report

SUPPLEMENTAL CROSS-SECTION DATA

69

11,000
:::; 10,998
w
> Water. level
w
~
'" 10,996 July 15, 1982
w
'"
Z
'"
w 10,994
'"
w
....
'"
'" 10,992
X
0
'" Upstream Cobble and
"- 10,990
"-
~ boulders
....
w
w 10.988
~
i!;
;i
0 10,986
>::
'" 1 0,985.08
>
w
~ 10,984 0
w

EXPLANATION

GROUND POINT
10,986.71 ELEVATION
16 STATION
HWM HIGH WATER MARK

Grass, cobble,
and boulders

Downstream

10,984.46
82

HWM
1O,M4.13

10,982
o

5

'0

15

20

25

30

35 40 45 50 55
STATIONING, IN FEET

60

65

70

75

80

85

90

FIGURE 57.-Lawn Lake dam cross section of breach Oeft side) on the Roaring River at river mile 0.0.

10,820
Left bank Right bank
10.818
10.816 0,817.80IHWMI Water level Jul 15, 1982
0 10,813.40IHWMI
:::; 10,814 185 "-
w
> n = 0.080 n=O.15l1) n= 0.050
w
~ 10.812
'"
w
'"
z 10,810 o su,\~e_ 10,808.8
'" 10.810.0
w 'Pt~~-- 144
'" 104
10,808 Estimated --
w I
.... 10,807.4 -----,
'" ~ l_...1 10,805.8
'" 10.806 Dense trees and
X '02 debris
0
'" 10,804 Boulders. trees, Grass and
"-
"- an@llog jams occasional trees
~
.... 10.802 Boulders, trees, and 10.801.' EXPLANATION
w 92
w
~ debris . GROUND POINT
i!; 10,800
;i 10,809.8 ELEVATION
0 10.798 144 STATION
>::
'" n MANNING'S ROUGHNESS
>
w 10,796 COEFFICIENT
~
w
10,793.4 HWM HIGH WATER MARK
10,794 10,793.4
34 80
10,792 10,792.3 10.792.0
72 86
10,7900 20 40 60 80 100 120 140 160 180 200

STATIONING, IN FEET
FIGURE 58.-Roaring River cross section at river mile 0,55.