Government of Nepal Ministry of Irrigation Department of Irrigation Irrigation and Water Resources Management Project (IWRMP) Mahakali Irrigation System – Stage I Canal Operation Plan Draft Final Report Prepared by Desh Bhakta Mallik WME-MIS April, 2016 Table of Contents of Canal Operation Plan Chapter-1 Introduction 1.1 General Background 1.2 Background of the Existing Problems 1.3 Objective of Canal Operation 1.4 Scope of Canal Operation Plan 1.5 Organization of document Chapter-2 Physical System 2.1 Background of the Project 2.2 Inventory of Canal Structures 2.2.1 Main Canal 2.2.2 Branch Canal 2.2.3 Secondary Canal 2.2.4 Tertiary Canal 2.3 Climatic Resources 2.3.1 Climate 2.3.2 Rainfall 2.3.3 Temperature 2.3.4 Relative Humidity 2.3.5 Evaporation 2.3.5 Sunshine Hours 2.3.6 Wind Speed 2.4 Land Resources 2.4.1 Land and Soil Types 2.4.2 Percolation Losses 2.5 Cropping Pattern 2.6 Operational Status Chapter-3 Irrigation Plan 3.1 Water Resources 3.2 Proposed Cropping Pattern 3.3 Soil Saturation Requirement 3.4 Land Soaking and Land Preparation Requirement 3.4 Conveyance Capacity and Irrigation Efficiency 3.5 Diversion Requirement 3.6 Water Balance 3.7 Water Allocation, Distribution and Scheduling 3.8 WUA Policy of Water Distribution Chapter-4 Organization for Canal Operation Plan Management 4.1 Existing Organization 4.2 Procedures of Canal Operation and Communication 4.3 Proposed Personnel and Skill Required 4.4 Proposed Organization and Staff Scheduling Chapter-5 Monitoring and Evaluation of Canal Operation 1 Chapter-1 Introduction 1.1 General Background Mahakali Irrigation System is a large-scale Agency Managed Irrigation System of Terai. Command area of this system was developed in two stages. About 5 years ago, irrigation management of Mahakali Irrigation System, Stage -1 (MIS-I) has been transferred to WUA Regional Committee, under Irrigation Management Transfer (IMT) component (Component- B) of Irrigation and Water Resources Management Project (IWRMP) of Department of Irrigation (DoI). The WUA will operate and maintain the transferred system below main canal as per the legal transfer agreement guidelines. The responsibility of operation and maintenance of main canal remains with DoI, Mahakali, Pathraiya, Mohana Irrigation Management Division (MPMIMD). The overall objective of this component is to improve service performance and service delivery of MIS-I. The Component-B is designed to address the problem in large public irrigation schemes (AMIS or agency –managed irrigation systems) of below –capacity performance, poor O&M, negligible cost recovery (below 5 percent on average) and inadequate maintenance funds. The Component-B is to provide improved arrangements and instruments for operation and maintenance (O&M) to AMIS for empowering WUAs to operate, maintain and manage parts of the irrigation systems for their sustainability. Canal Operation Plan is such an instrument expected to help in improving the service performance and service delivery. The Component-B aims to achieve : (i) improved physical performance of the MIS-I; (ii) reliable bulk water service delivery from main canal to off-taking branch and minor canals by DoI, MPMIMD, and (iii) efficient and equitable service delivery from branch and minor canals to tertiary canals, and from tertiary canals to field outlets by WUA. Therefore, COP should focus on making bulk water service delivery from main canal to branch and minor canals reliable, and service delivery from branch and minor canals to tertiary canals, and from tertiary canals to field outlets efficient and equitable. Basically canal operation is the process of releasing, conveying and dividing water in the canal system to ensure predetermined flows at prescribed times for specified durations at demarcated points of delivery. However, it should be reliable, safe, efficient and equitable. For making the water delivery reliable, safe, efficient and equitable, it should be well informed to WUA and farmers. It can be done through introducing water delivery schedule. The water-delivery schedules are defined by the following characteristics: Frequency (How often the water arrives?); Rate (How much water flows per unit of time?); Duration (How long is the flow rate delivered?); Timeliness (Does the water arrive when the crop needs it or the farm can use it?). 1 The traditional canal operation is supply oriented in which the flow is determined by upstream supply source or inflow. However, it involves large water loss, because the water allocation and water delivery schedule are based on the water right and the supply does not reflect the actual crop water demands. The modernization irrigation calls for demand oriented canal operation, in which water delivery schedule is prepared based on crop water requirement. The demand oriented scheduling could save as much as 50% of water supply compared with supply oriented approach. However, this approach poses problems from the point of view of practical canal operation, because of flow variations and hence the operation requirements in the tertiary canals will be high. Also, frequent adjustment in check gate of main canal would be necessary to achieve the required performance. This approach provides flexibility to farmers in terms of time and volume of water, but the complexity of operation and burden of operator increase with the freedom of water use increases. In IMT irrigation system, which is managed by WUA, water delivery schedule should be simple and user friendly. Supply oriented water delivery schedule is simple and user friendly, but water loss is very high. On other hand demand oriented approach is more efficient than supply driven approach, but the canal operation is complex. Therefore, water delivery schedules should be prepared first on the basis of supply oriented approach, and later they could be gradually modified based on the actual demand of crops, when farmers will be able to convey about their demand for irrigation water to WUA tertiary committee and the tertiary committee can communicate farmers’ demands to upper level WUA and eventually to MPMIMD, who is responsible for operation of main canal. Water delivery schedule alone is not sufficient for improving the service performance of irrigation system. Water distribution procedures and regulations are equally important. In addition, organization and management of operation are also essential. Finally, implementation of canal operation plan, water measurement at strategic points (such as at border weir and bulk water delivery points) and monitoring and evaluation of canal operation process and the service delivery are also vital. 1.2 Background of the Existing Problems In MIS-I water availability from Sarada Barrage is assured as per Indo-Nepal agreement 1996 AD. Here, the problem is mostly related to operation management and maintenance management of irrigation system. As far as the canal operation is concerned, supply oriented approach has been followed for years. MPMIMD requests Sarada Barrage Authority to release the requested discharge into the main canal. During monsoon season, about 12 cumecs of water is released. In case, for any reason such as excessive rainfall, the water demand in command area is reduced, MPMIMD requests Sarda Barrage Authority to decrease the discharge into main canal as requested. In this way, when the demand is decreased or increased, the supply from the barrage is adjusted as requested by MPMIMD. During dry season (winter and spring), the barrage authority releases more than assured discharge of 4.25 cumecs. In both monsoon and dry season when water is not demanded, barrage authority closes the flow into main canal as per request of MPMIMD. Decision on date of opening and closing of main canal is usually done by MPMIMD in consultation with WUA Central Committee. The water guards distribute the water from main canal to branch and minor canals with their past experiences and in consultation with WUA. In monsoon season, water is delivered in all the branch and minors continuously. In dry season, day time water is distributed to all the 2 branch and minor canals of MIS-I and in the night all these branch and minor canals are closed and whole water is conveyed to MIS-II. Although water availability in MIS is sufficient, tail end and remote farmers do not get their share of water. In winter, the tail end farmers complain that they do not get water in time. Head and middle farmers leave all the water when they do not need any more, which damages the crops. Water management practices are not followed. For example, Water delivery schedules are not prepared. Gauges are not painted on water measurement structures. Measurement of bulk water delivery from main canal to branch and minor canals are not done regularly. Control structures of main canal such as head regulators and cross regulators need repair and maintenance. Distribution of water to the tertiary canals is not equitable. Head and middle tertiary canals take more water than their share. In addition, illegal pipes have been inserted into canals to steal water. As a result, tail end tertiary canals do not get their share of water. WUA Tertiary Committee is not active towards equitable distribution of water among farmers. Head and middle committees are not active because their tertiary canals get sufficient water and tail end committees are not active because they think their voice will not be heard. Also, regional and block committees do not assist and encourage them in operation and maintenance. In this way, service performance and service delivery of MIS-I are poor and need improvements. WUA Regional Committee and Blocks Chairpersons of MIS-I informed that: There is no rule of operating canal and distributing water to the tertiary canals. There is no schedule of distributing water from outlets to the farmers’ plots. When canal is in operation, farmers open the gate to take out maximum water flow in their tertiary canals.