PROJ00076

• Contract/PO #: C153564
• Contractor Name: Bauer Lakes Water Company
• Contract Type: Loan
• Water District: 34
• County: Montezuma
• Bill Number: HB 85-1042
• Loan Projects - Doc Type: Feasibility Study

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led for a toe drain design in 1983 revealed a rather uniform
underlaying of sandstone for the entire length of the pro-
posed reconstruction area.

c. Design.1.The outlet works, Le., the gate and conduit are
the only hydr~ulic features requiring sizing. The formula
Ht=Htr+He+Hv+Hb+Hf+Ho will be used to compute the required
outlet conduit size. Since a little less than 5 cfs is
necessary to satisfy the needs of the upper reservoir
shareholders, it is apparent that the size of the reinforced
concrete pipe should be the smallest size practical to
install.

The upper system, however, is frequently used to help fill
the larger reservoir below. At the maximum depth of 18 feet,
a 12 inch gate and conduit would only discharge 7.36 cfs and
a 15 inch conduit, only 11.50 cfs.

I recommend an 18 inch R.C. outlet conduit, which will
discharge 16.57 cfs at 18 feet- of head and 12.95 cfs at the
low working head of 11 feet. The 18 inch pipe would also
lower the reservoir approximately 1 foot a day in the event
of an emergency.

(2) & (3) are not applicable.

(4) Spillway design. The reservoir is an off-channel storage
facility, with only 0.67 square miles of drainage above it.
Using the 1 square mile, Figure 4.5 of HYDROMET NO. 49, we
canexpect a PMP of 7.4 inches. The median elevation for the
drainage area is 7800 feet, so a reduction of 14% is called
for, leaving a PMP of 6.36 inches.

The USWB T.P. No.4 shows a 3.00 inch P for the 6 hour
intensity, 100 year frequency storm. I will calculate the
peak discharge and storm volume for both the PMP and the 100
year storm. Since the State Engineer is willing to consider
each watershed and storage facility on a case by case basis,
I propose to offer the 100 year storm because of the
characteristics of Chicken Creek, and no one lives within the
floodplain of the 100 year storm.

PMP HYDROGRAPH: SOIL COVER COMPLEX METHOD

DATA:Hydrologic soil group B
Condition - Range, Good
S.C. Number - 61
Area - 0.67 square miles
Length of drainage - 8400 feet
Slope - 5%
Channel Case - III
V = 7 fps
*********************.*.*...**********........

Tc=L/3600v = 0.33 hours

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