1.0 INTRODUCTIONAn open channel is a conveyance in which water flows with a free surface. When discharge remains the same and depth does not change then we have uniform steady flow. Therefore the velocity of flow, V and the flow rate, Q can be determined by Mannings equation. where R= Hydraulic RadiusA= Area of the water flowS0 = Longitudinal Slopen = Manning roughness coefficient

The hydraulic capacity of a drainage channel is dependent on the size, shape, slope and roughness of the channel section. For a given channel, the hydraulic capacity becomes greater as the grade or depth of flow increases. The channel capacity decreases as the channel surface becomes rougher. A rough channel can sometimes be an advantage on steep slopes where it is desirable to keep flow velocities from becoming excessively high.For this project, we have to choose one drainage channel in University Tun Hussein Onn to study the open channel flow by estimate the velocity of water flow, V and the flow rate, Q using technique like Water level method.

1.1 OBJECTIVE1. To understand the practical application of mannings equation.2. To be familiar to the hydraulic design of open channel.3. To explore the technique used in determining the channel slope Water level method.

2.0 STUDY AREA

The channel 14 we chosen to carried out was adjacent to C10 building. As from the picture above shown this channel is just located beside the pathway and there have some trees planted beside it. We went to do our measurement on 12th May 2014 at around 5.30p.m and the weather was sunny and windy.AB

The geometry of the channel 14 is combination of semicircle and trapezoidal structure and as shown in the picture above, the base surface of the channel was rough, not flat and has some debris on it. The channel slope S0 at point A is higher than at point B, therefore the flow direction of the channel are from point A to point B as shown in the picture above.3.0 METHODS AND EQUIPMENT

Equipment:1. Ruler1. Water level tube1. Stopwatch1. Measuring tape1. Ping Pong ball

Methods:1. Drainage Slope DeterminationAwater levelis a device used for matching elevations of locations that are too far apart for aspirit levelto span. By using the concept of water level, the slope of drainage can be determined by measuring the height of water level at two different points and the length between two points.For this, our group has used the water level method by using the tube. It is the simplest water level method with a section of clear tubing partially filled with water. During the whole process, the ends of tube were held vertically, and the rest of the tubing lied on the ground of drainage. Then, the heights of water level at the two different fixed points (H1 and H2) were recorded with the length between them fixed at 2m. For your information, whether or not the two ends are adjacent, the water level at these ends will still be maintained at same elevation. Finally, the slope of the drainage can be determined by using ratio method.

Where;H1 & H2 = height of water levelL = length between the two pointsS = slope of drainage1. Drainage Geometries DeterminationFirst, the curvature of the drainage was determined by placing the water level tube along the interior side of drainage. Then, the length of the tube is measured with measuring tape. Due to the small size of drainage, the depth, drainage bottom radius and top width were measured by using ruler. To make sure the accuracy, all these measurements were done on-site at three different sections of drainage: upstream, middle and downstream within the 2m reach. With these information recorded, the area and wetted perimeter of the drainage were calculated and shown at the analysis part of this report.

1. On-site ActivitiesAt the beginning, we filled the selected drainage with water so that it could act like an ordinary channel. Within the 2m reach we have measured, a Ping Pong ball was put on the upstream. For your information, Ping Pong ball was selected as it is light and its weight can be neglected. Time was recorded for the ball to flow from the upstream to the downstream. This activity was purposely done to observe the flow of the drainage and roughly estimate the velocity of flow.whereV = velocity of flowL = length between the upstream and downstreamt = time for Ping Pong to flow from upstream to downstream

Depth of drainage was measured with rulers

Top width of drainage was measured with ruler

Water was poured into the dry drainage

4.0 VELOCITY AND DISCHARGE OF FLOW4.1 CALCULATIONUPSTREAMRadius 1, R1 =11.00 cmDepth 1 =14.40 cmTop Width 1 =23.50cmMIDDLERadius 2, R2 =11.00 cmDepth 2 =15.00 cmTop Width 2 =23.50 cmDOWNSTREAMRadius 3, R3 =11.0 cmDepth 3 =15.60 cmTop Width 3 =23.50 cmAVERAGERadius = (11.0 + 11.0 + 11.0)/3 = 11.0 cmDepth = (14.4 + 15.0 + 15.6)/3 = 15.0 cmTop Width = (23.5 + 23.5 + 23.5)/3 = 23.5 cm

By using AutoCAD, we can determine the partial circle at bottom has the radius of 11 cm with the angle of 154. Thus, we can determine the area for the drainage.Area of A = C is the central angle in DegreesR is the radius of the circle which the segment is apart. is pi, appromaximately 3.142Sin is the trigonometry Sine function.Area of A= /2(3.142 x 154 /180 - )= 136.11 Area of B= ( 22 + 23.5) (4)= 91Total Area, A= 136.11 + 91= 227.11 Wet Perimeter, P= 2(4.07) + 2(11) ()= 37.71 cmHydraulic Radius = A/P= 227.11/37.71= 6.02 cm

UPSTREAM5.8cm7.5 cm200cm

At site, we measure the height of the 1st point, H1 = 7.5 cm and the height of the 2nd point, H2 = 5.8 cm, while the length between two points is 200cm.Thus, S0 = (7.5-5.8)/200S0 = 0.0085The average longitudinal slope= (0.0095+0.0105+0.0085)/3= 0.0095

MIDDLE6.1cm8.0 cm200cm

At site, we measure the height of the 1st point, H1 = 8.0 cm and the height of the 2nd point, H2 = 6.1 cm, while the length between two points is 200cm.Thus, S0 = (8.0-6.1)/200S0 = 0.0095

DOWNSTREAM6.4cm8.5 cm200cm

At site, we measure the height of the 1st point, H1 = 8.5 cm and the height of the 2nd point, H2 = 6.4 cm, while the length between two points is 200cm.Thus, S0 = (8.5-6.4)/200S0 = 0.0105

The surface material of experimental drainage is mortar cement. Therefore the value of manning roughness coefficient, n of the drainage we choose from the table of manning roughness coefficient is 0.011.

Hydraulic Radius, R = 6.02 cm = 0.0602 mArea of the water flow, A = 227.11 cm2 = 0.022711m2Hydraulic depth, D = 0.022711m2 / 0.0235m = 0.97mLongitudinal Slope, S0 = 0.0095Manning roughness coefficient, n = 0.011

Maximum velocity of drainage, V = = = 0.0309 m/s

Q= AV= 0.022711 x 0.0309= 7.02 x 10-4 m3/sFroude Number Fr = = = 0.01Since the Froude number Fr is less than one, therefore the flow in the channel 14 is sub-critical flow.

5.0 CONCLUSIONAs a conclusion, our group used water level method because this is the simplest water level method with a section of clear tubing partially filled with water to determine the drainage slope. The slope of the drainage is determined by using ratio method then. Based on the depths, we decided the upstream, middle and downstream part of the channel. By using Manning flow resistance equation, we calculated the maximum value of velocity, V = 0.0309 m/s. From the maximum velocity we obtained, the flow type of the channel is consider as sub-critical flow by using Froude number equation Fr = v/gD . The flow rate, Q of Channel 14 is calculated by using equation Q= AV and the value of Q obtained is 7.02 x 10-4 m3/s. From our point of view, the result will be more accurate if the channel is filled with water itself rather than us filling water into it. During this project, we encounter some problems such as insufficient time for group discussion and difficulty to meeting up all members and etc. However, we were able to accomplish this project with the help from our lecturer and do some reference from other sources. Through this project, we have learn that how to carry out water level method to determine drainage slope and we are able to understand the practical application of mannings equation on the calculation of velocity and flow rate Q.

6.0 REFERENCES1. Mr Wan Afnizan Bin Wan Mohamed. Department Of Water and Environmental Engineering, Faculty of Civil and Environmental Engineering, UTHM. e-mail: afnizan@uthm.edu.my, Hydraulic Notes (BFC21103).2. Puan Noor Aliza. Department Of Water and Environmental Engineering, Faculty of Civil and Environmental Engineering,UTHM. Fluid Mechanics Notes (BFC10403).3. Encik Mohd Adib bin Razi. Department Of Water and Environmental Engineering, Faculty of Civil and Environmental Engineering,UTHM.4. Open Channel Flow. Retrieved on May 20th ,2014 at 11.00am from http://en.wikipedia.org/wiki/Open-channel_flow5. Calculation of Critical Depth and Critical Slope for Open Channel Flow. Retrieved on May 21th ,2014 at 2.00pm from http://www.brighthubengineering.com/hydraulics-civil-engineering/122607-calculation-of-critical-depth-and-critical-slope-for-open-channel-flow/

7.0 APPENDIXa. Approximate locations of the 17 identified open channelsThis is our channel (Channel 14)

b. On-site Activities

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