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ContentsIntroduction .................................................................................................................................................. 3

Study Area ..................................................................................................................................................... 4

Method and Equipment ................................................................................................................................ 5

Determined the Longitudinal Slope of Channel 13 ................................................................................... 5

Determined the Velocity of Water Flowing in Channel 13 ....................................................................... 6

Determined the Area of Channel 13 ......................................................................................................... 6

Velocity and Discharge of Flow ..................................................................................................................... 8

Conclusion ................................................................................................................................................... 11

Reference .................................................................................................................................................... 12

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Introduction

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Study Area

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Method and Equipment

Determined the Longitudinal Slope of Channel 13

The longitudinal slope of the channel was determined by water level method using a

transparent hollow tube. A water level is a device used for matching elevations of locationsthat are too far apart for aspirit level to span. The procedures include:

Filled the pipe with water till nearly full.

Hold both ends vertically and taps the pipe gently to expel those entrapped air. Then holdthe ends of the tube even with one another, and verify that the water lines up equally.If it

does, you are ready to go. If it does not, you need to continue tapping the tube, as it's

likely that air bubbles are still trapped.

A mark is marked a few centimeters away from both ends to act a guideline when

measuring the slope of the channel. The ends are held vertical, and the rest of the tubing lies on the ground or floor as in

figure below.

The H1 (height of water for one side of the pipe), H2 (height of water for the other side of

the pipe)and L (the length between two mark) for the upstream, middle and downstream

of the channel were measured using a ruler and average was taken. From the average

value, the slope can be calculate using the formula below:
http://en.wikipedia.org/wiki/Spirit_levelhttp://en.wikipedia.org/wiki/Spirit_level

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Determined the Velocity of Water Flowing in Channel 13

The velocity of the water flowing in the channel was determined by:

Poured the water to the channel and allow it to flow.

Once the flow is constant, placed a floating object on upstream of the channel and

allowed it to transit to downstream.

The time taken for the object to flow from upstream to the downstream was recorded.

These processes were repeated several times to obtained higher accuracy data.

The velocity of flow can be calculate using the formula below:

Determined the Area of Channel 13

By using AutoCAD, we can determine the variables for partial circle at bottom of the channel

(circular) and the upper part of the channel (rectangular). Thus, we can determine the area for the

drainage.

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The area of channel can be calculated using the formula below:

Total Area = Area of A + Area of B

= (T x Y) +

Where T is the top width of rectangular section

Y is the height of rectangular section

D is the diameter of circular section

is the center angle in radian =

Sin is the trigonometry sine function

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Velocity and Discharge of Flow

1. Calculate the longitudinal slope of channel, s0

From the water level result obtained, h1=14.4 while h2=13.3, therefore the difference in

height h is

From the measurement obtained L= 264 cm

Thus the longitudinal slope can be calculated using the formula below:

2. Calculate the velocity of flow in the channel, v

The velocity can be calculated using the formula below:

Distance travel was set as 1m and the times recorded were 3.58 seconds.

Therefor velocity,

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3. Calculate the area of channel, A

The area of the channel is:

Thus,

4.

Calculate the wetted perimeter of channel, P

The wetter perimeter equal to:

5. Determine the Manning roughness coefficient , n

The Manning Roughness Coefficient value can be determined from the Table 1: Value of

Manning roughness coefficient, n (Chow, 1959).

According to the characteristic of the channel, which is (1) lined or built-up channel with

(2) nonmetal and (3) made form concrete at the bottom float finished with (4) sides of

random stone in mortar, it manning roughness coefficient is 0.020.

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6. Determine the Hydraulic Radius, R

The hydraulic radius can be calculated using the formula below:

7. Calculate the rate of flow, V

The rate of flow, Q can be calculated using the formula below:

n = 0.020

A = 426.80cm2= 426.80 x 10

-4m

2

R = 7.86 cm = 7.86 x 10-2

m

So= 1/240

( )

8. Calculate the rate of flow, Q

The rate of flow can be calculated using the formula as shown below:

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Conclusion

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Reference1.

Gary P. Merkley. (2014). Channel Cross Sections. Retrieved 23 May 2014, from

http://ocw.usu.edu/Biological_and_Irrigation_Engineering/Irrigation___Conveyance_Control_Sy

stems/6300__L16_ChannelCrossSections.pdf

2.

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