PERMFILE65277

• Permit No: M1988101
• IBM Index Class Name: Permit File
• Doc Date: 11/1/1990
• Doc Name: HYDROLOGY AND HYDRAULICS FONIS PIT ACCESS ROAD CULVERTS
• Section_Exhibit Name: ELBERT COUNTY
• Media Type: M
• Archive: No

V
W
C)
Z'
Z
2
f—
a-
W
J
Q
la.
Z
a
a
0
3
2
1
0
(MINUTES) 5
10 16 20 26 30 40 60 60 60 100 120 160 160 240 im 360
1 2 3 4 5 6
BASIN DATA
DURATION IN MINUTES AND HOURS
5
4
3
2
1
E
8 10 12 14 16 18 20 22 24 (HOURS)
RAINFALL DEPTH - DURATION GRAPH
FROM: Denver Regional Council of Governments
6: Wright— McLoughlin Engineers
BASIN AREA = 11.5 sqr miles (7300 acres)
BASIN LENGTH - 6 miles
BASIN SLOPE (.1L to .85L) _ (6600 - 6200)/4.7 — 85 ft /mi
SOIL TYPES: (and SCS hydrologic group)
Mid Slopes —> Kutch — "C ", Bresser — "B ", Cushman — "C"
Uplands —> Brusset — "Be, Peyton — "B ", Elbeth — "B"
All areas classified as "rangeland — fair"
SOIL TYPE AREAS:
as short term access to
a gravel pit.
No public traffic will use this crossing. The proposed
Hydrologic Group
B — 9.6
sqr. miles
(6100 acres)
Hydrologic Group
C — 1.9
sqr. miles
(1200 acres)
SCS CURVE NUMBERS:
which will allow the stream to
flow at natural depth and
velocity. The
Hydrologic Antecedent
Moisture
Conditions
Group
Dry
Avg.
Wet
B
69
85
97
C
79
90
98
Design CN — (9.6/11.5)69 + (1.9/11.5)79 - 71
INFILTRATION LOSSES:
S 1000 /CN — 10 = 1000/71 — 10 = 4.08
qr = (p — .25) [3.9 — (.2)(4.08 }] = 1.3 Inches (runoff after infiltration)
(p + .8S) [3.9 + (.8)(4.08)]
TiME OF CONCENTRATION:
Overland now per SCS:
3000 ft. O 6.67% w/ avg velocity of 2.75 fps
Ti = 3000/2.75 — 18 minutes
Channel Flow per Kirpich eqn:
LM77 27,000
Tch — .00013 • ss - .00013 • 0.3s6
g a .016
Tch = 1.65 hours
Total Time of Concentration:
Tc = .30 + 1.65 = 1.95 hours use 2 hours
25 YEAR 24 HOUR PEAK FLOW:
Q = 185 a AREA • qr (from SCS "Peak Discharge as Function of Tc ")
Q= 185.11.6 +1.3 -2800 cis
NATURAL CHANNEL FLOW:
n =.04
S — .016
Rh —d =5'
V = (1.49 /n) �•� - 13.8 fps
Therefore channel will flow naturally O approximately. (w /o backwater)
14 fps
5 feet deep
40 feet wide
y
Tiedown
T
I
ROADWAY EMBANKMENT
CULVERTS
(2ea 6' 0 x 40 feet)
Depth approx. 5'
per CWCB eqns.
-I— II Ili
' I I Channel bottom
SECTION ® CROSSING
Roadway Surface
IS
351
1 I . r . 1 ,
SECTION A
Low —point in roadway
A single 6' 0 culvert, under outlet control, will carry
approximately 240 cfs when inlet Is 3' submerged.
(Source: AISC Steel Drainage Structure Design Manual,l, fig 4 -35)
Permit Number n)
Class'e't-ernin 1 ,1�-1}
SectioniExhibit
Classy ❑ Rev ision
TYPe /Se9:
i _._._._._._._i
_ _._ ------- I
Class: O Report 0 Hydro ClGeneral -- - -- - '-' -'-
Doc Type:
OApplication (Coal only) ❑ Bond O Enforcement O Inspection
BASIN PLAN
SCALE: 1" = 5000'
DESIGN PRINCIPAL: This crossing is proposed
as short term access to
a gravel pit.
No public traffic will use this crossing. The proposed
structure will
pass approximately 20% of the
25 year storm before the
road overtops
between the culverts. The overtopping will wash out the
road between
the culverts, and the culverts
will provide a stable
channel bank
which will allow the stream to
flow at natural depth and
velocity. The
owner is aware of the risk of
regular wash out, and
accepts that
risk. The owner also owns the
property immediately down-
stream from
this site. Sediment introduced
into the stream, during a
washout, will
be minor in comparison with natural sediment transport
during even a
1 year event.
RECEIVED
NOV 0 11990
Mined Land
Reclamation Division
11 1 - d 2f
HYDROLOGY & HYDRAULICS
FONDIS PIT ACCESS ROAD CULVERTS
OVER W. BIJOU CREEK TRIBUTARY
ELBERT COUNTY, COLORADO
Wo P E C TR U M ENGINEERING do MANAGEMENT, INC.
P.O. OW 1716 MONTROSE. COLORADO 81402 (303) 249 -7974
SCALE: 1' = 5000'
DATE: 10/31/90
REVISED:
ENGINEER: JA
JOB NUMBER: 5105
SHEET: H1
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