WSP05388

• File Number: 8449
• Description: Platte River Projects
• State: CO
• Basin: South Platte
• Date: 9/9/1980
• Author: USGS
• Title: Hydrologic Analysis of the Proposed Badger-Beaver Creeks Artificial-Recharge Project, Morgan County, Colorado
• Water Supply Pro - Doc Type: Publication

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'Because the widths, slopes, and numbers and types of check gates are quite
:similar for most of the canals in this part of the South Platte River valley,
'the above function is believed to be representative. For the rest of the ca-
,nal system, Manning's equation (Chow, 1959) was iteratively solved until the
'computed discharge equaled the routed discharge. This is an iterative process
:because the hydraulic radius is a function of wetted perimeter which is a
:function of depth:

Q_1.486 .A 'RZ/3.S 1/2
n cO'

(3)

A =h.rl and
c '

(4)

hW
R=AcIP=Zh+W (for rectangular channel),

(5)

I
'whe re

Q is the discharge of the canal J in cubic feet per second;
n is the ~\ann ing' s coeffi c i ent;
A is the cross-sectional area of water in the canal, in squa re feet;
c
R is the hydraulic radius, in feet;

So is the dimensionless channel slope;
h is the depth of "ia te r in the channel, in feet;
W is the average width of water in the channe I, in feet; arid

P is the wetted perimeter, in feet.

The flows were distributed through the system by trying to make the di-
versions at branching nodes (fig. 7) such that water just reached the termi-
nal node (fig. 7). If there was less water than potential leakage, then water
was diverted to each section on the basis of section number and potential
seepage rate. The water was diverted to each section until all the water was
used; and the last sections would receive less than their potential, or none,
,if the excess water was gone. If there was more water avai lable than the com-
bined potential leakage rates, the extra water was apportioned evenly to all
the ponds. Proportioning the flow at points of diversion was a trial-and-
error routine. Because seepage is partly a function of the hydraulic head in
the canal, whenever the diversion through a section of' the canal system
changes, the seepage also may change. The technique used to distribute water
at a branching node (fig. 7) was to divert exactly the amount of water needed
so that the seepage in the last reach causes the flow at the terminal node of
the section to be zero. This was an iterative process whereby all of the
water was initially diverted into one section. The amount of outflow at the
end of the section was then subtracted from the first diversion, to determine
the estimated second iteration diversion. Because the seepage decreased with
the new decreased diversion, there still was outflow from the section and the
process was repeated. A schematic of the number of branching nodes that had
to be repeatedly solved is shown in figure 7.
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