HYDRAULIC DESIGN OF PIPE DISTRIBUTION NETWORK FOR IRRIGATION PROJECT

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1 International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 7, July 2018, pp , Article ID: IJCIET_09_07_116 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed HYDRAULIC DESIGN OF PIPE DISTRIBUTION NETWORK FOR IRRIGATION PROJECT Santosh Patil M.Tech Student, Department of Civil Engineering, Bharati Vidyapeeth Deemed University, College of Engineering Pune, Maharashtra, India S.D. Talegaonkar Assistant Professor, Department of Civil Engineering, Bharati Vidyapeeth Deemed University, College of Engineering Pune, Maharashtra, India P.T. Nimbalkar Professor, Department of Civil Engineering, Bharati Vidyapeeth Deemed University, College of Engineering Pune, Maharashtra, India ABSTRACT This paper deals with designing of gravity main of the Pipe Distribution Network (PDN) System. It also includes estimation of saving in water due to adoption the PDN system and also studies alternatives for the utilization of saved water. The project discusses about various available equations for calculation of the head loss in pipe. In this project the PDN system is designed with help of Modified Hazen William Formula. The project taken under consideration is Chilhewadi Medium Project in Pune district of Maharashtra state in India. The estimation of the saving works out to be Mcum of water. The alternatives studied for the utilization of this water is according to water policy adopted by the Maharashtra State Government. The utilization of the water serves drinking water needs of nearly 6758 population from two water scarcity villages of Pune and Ahmednagar districts. It also helps in bringing 41 ha of land under irrigation of the same area. The utilization of water was studied by using established Canal network system of adjoining projects and also through proposed Pipeline system of the Chilhewadi Project. The alternative comprising use of existing adjoining Pimpalgaon Joge Canal by lifting of water proves to be economical. Key words: PDN Design, Modified Hazen William equation, Junnar, HGL. Cite this Article: Santosh Patil, S.D. Talegaonkar and P.T. Nimbalkar, Hydraulic Design of Pipe Distribution Network for Irrigation Project. International Journal of Civil Engineering and Technology, 9(7), 2018, pp

2 Hydraulic Design of Pipe Distribution Network for Irrigation Project 1. INTRODUCTION Out of India s Ultimate irrigation potential of 140 million hectare about 102 million hectare has been created through major/ medium/ minor surface water irrigation projects and use of ground water. Even after creation of 102 million ha of irrigation potential, it s utilization is about 87 million hectare only. It is due to poor water use efficiency of conventional Canal Distribution System (CDN) of Irrigation Projects. It is assessed to be only of the order of 30-35%. Thus it is evident that the gap between irrigation potential created and utilized is due to poor water use efficiency. This gap can be reduced by using irrigation system which has highest water use efficiency. Therefore use of pipe distribution network (PDN) system is inevitable. The effectiveness of PDN system is possible only when there is 1) proper layout planning of PDN. 2) Proper selection of material of pipe, 3) Proper design of the PDN system, 4) Proper management and maintenance of the PDN. In view of above facts the present study deals with the design of the PDN system of irrigation project. It also estimates the saving of water due to use of pipe distribution network. The attempt has also been made to study various alternatives for utilizing the saved quantity of water. For this purpose Chilhewadi Medium Project in Maharashtra is considered which is originally planned for CDN. 2. DETAILS OF THE STUDY AREA Chilhewadi Medium irrigation project is about 125 km from Pune near Chilhewadi village of Junnar Taluka in Pune district. The project is on Mandavi River which originates in Sahyadri ranges in Ahmednagar district of Maharashtra state. As per original Detailed Project Report, the command area of the project is 6372 ha. The length of the command is nearly 40 km. The command area of the project lies in 20 villages of Junnar Taluka in the Pune District. The command is enclosed within hilly terrain on left side and by Pimpalgaon Joge irrigation project canal on right side Design Considerations for pdn This section describes the design standards of velocity, operating pressures, determination of Diameter of pipe for Main and Branch lines etc Permissible head Minimum driving head at intake should be 1.2 m. Effective head along the line should not be less than 0.6 m Maximum velocity Recommended maximum velocities in low pressure pipelines are in the range of 1.3 to 1.5 m/sec. The velocity up to 1.8 m/sec can be allowed to cut the cost in case of MS, PSC or HDPE pipelines. For pumping PDN system, design velocity should not exceed 2.0 m/s Minimum velocity Minimum flow velocities should be between 0.8 to 1.2 m/sec in order to prevent sedimentation of fine sand. In exceptional cases velocity can be allowed up to 0.6 m/sec with adequate scouring arrangement. Designers must specify pipe diameters and flow rates for irrigation systems that utilize emitters with small apertures editor@iaeme.com

3 Santosh Patil, S.D. Talegaonkar and P.T. Nimbalkar Exit Pressure at Irrigation Outlet a) For flow irrigation A minimum effective head is difference between H.G.L. and ground level at that point (i.e. H.G.L. G.L.). It must be 0.6 m in normal cases and in exceptional cases it can take a minimum value not less than 0.3 m. In low lying areas if H.G.L. is more, it should be reduced by using lesser diameter pipes or valve. b) For Micro Irrigation For micro irrigation systems Outlet pressure with design working pressure between 0.2 MPa and 0.4 MPa shall be used Overburden for buried pipes To avoid damage to pipeline due to farm operations, vehicular traffic loads minimum overburden of 1.2 m shall be provided for Main and Branch lines and 0.6m for distributaries and minors Air vent They are installed at all high points in the line, at sharp turns, at points of there is a downward deflection of more than 10 degree, directly downstream of any structure that may entrap air, and at the end of pipeline. They are also require immediately upstream from gates where closure of gates would make such points the downstream end of laterals or line. Also Air vent must be provided at 300m interval on main line. Air vent should extend minimum 0.6 m above H.G.L. The diameter of air vents is generally 10% of diameter of the Pipeline Drain Valves Drain Valves shall be provided at the lowest points near Nalla Scour Valves If the velocity in the pipes is less than 0.6 m/s, scour valves shall be provided as per the site conditions at deep nalla locations Outlets The diameter of the riser pipe is kept the same as the pipeline system where the entire flow of the pipeline is to be released through the valve. A field block of 5 to 12 ha provided with a separate outlet of required capacity, with the valve located about 15 cm above the field level with a division. 3. METHODOLOGY Steps in PDN Design Detailed steps involved in design of PDN for irrigation are as follows Calculation of water availability for irrigation at Source. Finalization of Command chaks after detailed survey. Calculation of Crop Water Requirement for the Project. Calculation of Discharge for Minors, Distributaries and Main canal. Finalization of Diameter of pipeline. Calculation of Hydraulic Gradient Line (HGL) / Head Loss. Checking adequacy of HGL. Check for the Design velocity and Residual Head editor@iaeme.com

4 Hydraulic Design of Pipe Distribution Network for Irrigation Project As steps a), b) and c) are common for design of flow CDN and PDN system, the data for these steps is readily available from Project report of the Chilhewadi Project. This paper deals with steps onward d) Calculation of Head Loss For calculation of HGL it is important to know the head losses in the system. The head loss through pipe can be divided in to two parts namely Major Head loss or Loss due to friction (hf) Minor Head losses or Losses due to change in Pipe geometry. There are various formulae available for calculation of head loss due to friction in pipeline like Manning s formula, Colebrook White equation, Darcy Weisbach formula and Modified Hazen-William s formula. The Modified Hazen-William s formula is the best of these formulae in case of pipes between hydraulically smooth and rough ones. This formula is most often used for designing irrigation systems Modified Hazen-Williams formula The Modified Hazen Williams equation is an empirical relationship which relates the flow of water in a pipe with the physical properties of the pipe and the pressure drop caused by friction. It is used in the design of water conductor systems including sprinkler systems for fire extinguishers, pipe irrigation networks and water supply systems. H L = (Q/CR) 1.81 x L x D 4.81 Where, H L = Head loss due to wall friction (m), L= Length of pipe (m), D = Diameter of pipe (m), Q = Flow rate (m3/s), CR = Coefficient of relative roughness of the pipe material Total Minor Losses In general for pipe system, head losses due to bends and valves comprises only 5 to 10 % of pipe friction losses and are frequently referred to as minor head loss. It is given by H m = Km V 2 / 2g Where, H m = minor head loss (m), K m = minor head loss coefficient, V = velocity before feature causing friction losses (ms -1 ).For preliminary estimation purpose, total minor losses may be taken as 10% of the major loss Design of Gravity Main For design of gravity main various calculations are carried out. For that purpose a programme in excel is developed to obtain desirable hydraulic gradient, pipe diameter for required discharge of the system. For this purpose pipeline is divided into number of nodes. The node points are selected on a pipeline where there is withdrawal of discharge from the pipe system or major change in gradient of the pipe line. The discharge statement for each node is prepared by considering command area below that node. The programme is developed in tabular form. The calculations for any segment of pipeline between two consecutive nodes are carried out in single row of excel sheet. Details of various columns in the in this statement are as follows Column 1: Staring Node number editor@iaeme.com

5 Column 2: End Node number. Santosh Patil, S.D. Talegaonkar and P.T. Nimbalkar Column 3: Chainage of Starting Node. Column 4: Chainage of End Node. Column 5: Length of Pipe segment between two Nodes. Column 6: Discharge at the start of the Node. This is taken from separately prepared Node wise Discharge statement. Column 7: Ground level at Starting Node. Column 8: Ground level at End Node. Column 9: Difference of Ground Level between two Nodes. Column 10: Residual head at the start of the Node. For very first Node it is calculated as difference between Full Supply Level of Intake Chamber (706.00m) and Ground level. For other Nodes residual head is calculated as difference between residual head of End node of previous pipe segment and Ground level of the start Node of this Pipe segment. Column 11: Total head available. (Column 9 + Column 10). Column 12: Diameter of pipe adopted. Column 13: Actual Head loss occurred between two Nodes. Calculation is carried out with Modified Hazzen William formula as discussed in previous chapter. Column 14: Residual Head at the End Node. (Column 10 Column 13). Column 15: R.L. of HGL (Column 8 + Column 14). Column 16: Velocity in Pipe ( Column 6 / Area of Pipe ) The check for the maximum velocity and minimum velocity is verified for every segment of the pipe. If check does not fulfill the criteria, then the diameter of the pipe is changed accordingly to fulfill the criteria. The check for the residual head is also verified. If check does not fulfill the criteria, then the diameter of the pipe is changed accordingly to fulfill the criteria. 4. ESTIMATION OF SAVING IN WATER DUE TO PDN Due to increased conveyance efficiency of PDN with respect to Canal Distribution Network (CDN), there is saving in overall use of water. For Chilhewadi Project as per DPR the overall efficiency of CDN is taken as % whereas that for Lift irrigation it is taken as 61.75%. Various studies cited above conclude that there is 70 to 80 % improvement in water use efficiency due to use of PDN. Even on conservative estimates as per the DPR of Chilhewadi, Overall efficiency of the Lift irrigation which resembles the PDN works comes out to be 61.75%. The difference of overall efficiencies between CDN and PDN of ( ) 13% is considerable. By considering conservative saving estimates of 13% total water saved in the project works out to be x 13/100 = 2.675Mcum Quantum of usable Saved Water As per original DPR, Chilhewadi project was conventional CDN irrigation project. All its controlling levels were fixed accordingly including Minimum Draw Down Level (M.D.D.L.= m), Open Canal Bed Level ( m), Full Supply Level of editor@iaeme.com

6 Hydraulic Design of Pipe Distribution Network for Irrigation Project Canal(703.00m). At the canal head depth of water was 1.33m. In Chilhewadi project reservoir is connected to Distribution system by 300m tunnel. As per design of PDN the full supply level of 706m is required in intake chamber. For new Full Supply Level of m, new M.D.D.L. must be at least above 2 m to have sufficient driving head. As per original DPR( for CDN) For M.D.D.L. is m, Dead Storage is 2.51 Mcum. As per PDN design requirements For M.D.D.L m, Dead Storage is Mcum. Additional Storage available for use =2.675-( ) = Mcum. The drinking water requirement is about daily 135 lit per capita. As per Chilhewadi project water requirement, 5298 cum of water is required to irrigate 1 ha of field. Therefore saved quantity of water can Supply drinking water to the population of 8000 or Irrigate additional ICA of 160 ha. As per the State water policy the priority for drinking water is prime to irrigation water, the saved water can be utilized for drinking water scheme. The area below tail end of command of Chilhewadi project is water scarcity area. Gulunchwadi village in Junnar taluka of Pune District having population 2626 and Kalas village in Parner taluka of Ahmednagar district has population of 4132, have drinking water demand for long time. The population is based on 2011 census and for design of water supply scheme for next 30 years; projected population with growth rate of 1.72% per annum comes out to be The combined water demand comes out to be Mcum for year. The balance Mcum quantity of water can be used for irrigation. This quantity can irrigate 41 ha of area. This can be achieved by Alternative 1 Figure 18 Canal Networks of Adjoining Projects editor@iaeme.com

7 Santosh Patil, S.D. Talegaonkar and P.T. Nimbalkar The excess water of Chilhewadi reservoir can be released into Yedgaon reservoir. This water can be released from Yedgaon reservoir in to Kukadi River or Kukadi Left Bank Canal. These villages lie about 10 km from left flank of Kukadi River. The drinking water can be supplied to the villages by lifting arrangement. This alternative costs around Rs Lacs. Alternative 2 These villages lie on left flank of Pimpalgaon Joge canal. The excess water can be discharged in Mandavi River which crosses Pimpalgaon Joge canal near Otur village and at canal chainage 13km. There is Otur Kolhapur Type (K.T.) weir on Mandavi River just below the crossing of Pimpalgaon Joge Canal and Mandavi River Lifting water in to Pimpalgaon Joge canal at chainage 13km and Supplying water to the villages at chainages at 45 km and 49 km respectively by lifting arrangement. The lifting arrangement for both the villages is separate. The Gulunchwadi village lie around 2.8 km and Kalas village lie within 500 m of the PJLB canal. This alternative cost around Rs 35.85Lacs. Alternative 3 By discharging water from tail out let of Chilhewadi Pipe line for 2.5km for Gulunchwadi and 3.5 km for Kalas village. As discharge of tail outlet is 10 liter per second (lps) and will not be sufficient to fulfill the demand of the area. For fulfilling the demand 70 lps discharge is required at the tail outlet. For this purpose, diameters of the CLBC pipe line are required to be increased beyond chainage m TO 39080m. The pipes having diameter 1000 mm have increased by 1780 m length where as saving of 500 mm diameter pipe length is in tune of 1720 m. This alternative costs for increased diameter of CLBC beyond chainage m is around Lacs. Thus Alternative 2 is economical and hence should be adopted 5. CONCLUSIONS The Modified Hazen William equation is suitable for calculation of head loss due to friction in PDN system. Adoption of underground PDN systems had lead to the reduction in conveyance and distribution losses. The estimation of saving of water due to enhanced efficiencies is carried out. Out of cum of saved water, the drinking water demand can be fulfilled of population of 6758 with 0.626cum and balance cum can be used to irrigate 41ha of the area in the villages. ACKNOWLEDGEMENT The authors express their deepest gratitude to Dr. A. R. Bhalerao (Principal), Bharati Vidyapeeth University College of Engineering, Pune, for their support and encouragement. The authors are also thankful to WRD, Maharashtra for their valuable cooperation and timely guidance during the course of project studies. REFERENCES [1] Bombardelli F.A. and Garcıa M.H, (2003) Hydraulic Design of Large-Diameter Pipes. Journal Of Hydraulic Engineering ASCE [2] Chinea R.R. and Dominguez A, Total Friction Loss along Multiple Outlets Pipes with Open End. Journal Of Irrigation And Drainage Engineering ASCE page [3] David C, (2001) Hazen-Williams C-factor Assessment in an Operational Irrigation Pipeline. A thesis submitted to Department of Agricultural and Biosystems Engineering, McGill University, Montreal editor@iaeme.com

8 Hydraulic Design of Pipe Distribution Network for Irrigation Project [4] Gadekar, R. G., Kute, S., and Sathe, N. J. (2015). Optimal Utilization Of Irrigation Water: A Case Study On Nashik Left Bank Canal [NLBC], Nashik, Indian Journal of applied research, Vol. 5, pp [5] Government of India, Central Water Commission, New Delhi.(2017) Guideline for Planning and Designing of Piped Irrigation network May2017. Page 1-99 [6] Government of Maharashtra State, India (2017) Guidelines for adoption of Pipe distribution system dated 2 February Page 1-11 [7] Kolhe P.S. (2012). Optimal Utilization of Irrigation Water by Use of Pipe Distribution Network (PDN) Instead Of Canal Distribution Network (CDN) In Command Area, India Water Week 2012, New Delhi. [8] Patel M., Sahita I. W., and Agnihotry P.G.,(2014). Replacement of Sub Minors with Pressurized Irrigation Systems: In Canal Command Area, Global Journal for Research Analysis, Vol.3 Issue 4, pp1-2 [9] Satpute M. M., Khandve P. V., and Gulhane M. L.,(2015). Pipe Distribution Network for Irrigation an Alternative to Flow Irrigation, Section VII: Environmental Sciences, Proc. 99th Indian Science Congress, Part-II: Abstracts of Poster Presentation. pp72-81 [10] Viliantaz J.D. (2008) Explicit Power Formula For The Darcy Weisbach Pipe Flow Equation: Application In Optimal Pipeline Design. Journal Of Irrigation And Drainage Engineering Asce / 134(4): [11] Yousef A. and Faisel Z., (2007). Improving Conveyance and Distribution Efficiency Through Conversion of an Open Channel Lateral Canal to a Low Pressure Pipeline at Al- Hassa Irrigation Project, Saudi Arabia, The Arabian Journal for Science and Engineering, Volume 32, Number 1 C pp editor@iaeme.com