Operation of irrigation systems implies a package of organizational & economic and technical arrangements that ensure planned distribution and full use of water resources for heavy yield of agricultural crops of good quality under irrigation conditions. Therefore, during the operation of irrigation systems their state and the condition and use of irrigated lands as well as proper water use should be taken into consideration.

Operational measures include the following:

• implementation of scheduled water use practice to provide the irrigation regime required under specific meteorological conditions on certain land areas under efficient water use;
• keeping irrigation, drain and other canals, pipelines and buildings in good working order by guarding, supervision, maintenance and repair of irrigation systems;
• prevention of inflow of excess water into irrigation system and diversion of excess water;
• control of water losses in canals and improvement of system efficiency;
• organization of irrigation water accounting;
• control over proper water use and groundwater conditions;
• management of forest vegetation along canals;
• control over crop management practice on irrigated lands;
• liquidation of salinization and waterlogging on irrigated lands.

Objects of irrigation system operation

Proper development of irrigated lands and streamlined function of irrigation system operating service are indispensable conditions for gaining heavy and sustainable crop yield.

Operation of irrigation system includes: implementation of scheduled water use in the system and in irrigated farms; keeping all system components in good working order; arrangement of their work in compliance with farm performance targets and depending on system operating conditions (climatic, hydrogeological, etc.); reconstruction of irrigation systems by adopting new techniques and technologies; control over efficient use of water and land resources; improvement of meliorative condition of irrigated lands; etc.

Irrigation systems are operated and maintained by special organizations: irrigation systems administrations (ISA); canal management organizations; administrations of hydroschemes; administrations of reservoirs; etc.

There are the following operating services:

• on-farm operating service that maintains irrigation network and irrigation equipment in farms-water users;
• inter-farm operating service that is in charge of the inter-farm irrigation network;
• basin operating service that distributes water from an irrigation water source among irrigation systems.

Depending on the area serviced, irrigation systems are divided into five classes as follows: Superior Class with an area of more than 50,000 ha; Class I – 50,000-26,000 ha; Class II – 25,000-11,000 ha; Class III – 10,000-6,000 ha; Class IV – 5,000-1,000 ha; Class V – less than 1,000 ha. According to the class, they establish the structure of operating management and standards of operational equipping (remote control equipment, water gauging stations, water measuring facilities, groundwater table observation wells, buildings and various auxiliary structures, roads, transport, tools, etc.).

On-farm operation of irrigation systems should be carried out in close cooperation with an agronomic service of farms.

On-farm operating service has the following duties: drawing up and implementation of water use schedules; control over water application process; cutting of temporary irrigation network; leveling of fields; preparation of irrigation equipment and irrigators; keeping of irrigation network and structures in serviceable condition by their timely maintenance and repair; cleaning of canals from sediments and weediness; keeping of operational equipment in serviceable condition; performance of tree-planting works; control of soil salinization and swamping; etc.

Operating management is divided into five groups depending on serviced area, capacity of reservoir, canal capacity, and other measures. The number of the management personnel is determined according to the group.

The area serviced by the operating management is divided into operational sections which carry out all types of repair and maintenance works. The number of executive employees, technical and engineering employees, office workers and operating personnel for each operational section is estimated according to standards.

Proper development of irrigated areas and streamlined works of irrigation system operating service are essential conditions for gaining heavy and sustainable crop yield.

According to data by A.N. Kostyakov, among efficient system operation indicators are: heavy and sustainable crops and high labor productivity; high efficiency of the system; improvement of of irrigated land productivity; low groundwater level; and absence of soil salinity; normal water consumption per unit area; good condition of canals and structures.

Irrigation system includes: head water intake structure; main, distribution and irrigation canals; irrigation facilities; and waste (tail-water) ditch and collection network. There are inter-farm irrigation systems that provide water application to the fields of several farms and on-farm irrigation systems that provide water application to the fields of a single farm only. Irrigation systems administrations (ISA) are responsible for operation and keeping in good condition, safety and proper use of main and inter-farm canals, pipelines and structures on them. The farm-water user is responsible for keeping in good condition and operation of the on-farm irrigation network.

Stages of irrigation system operation

1. Stages of irrigation system operation are broken down into stage of use and stage of maintenance.
2. Stage of irrigation system use consists in the implementation of the full range of system features responsible for its capability to meet the need for optimum water regime of soils as effectively as possible.
3. Stage of irrigation system maintenance consists in material and technical support, implementation of measures for restoration of good condition of irrigated lands (soil conservation) and technical maintenance, routine maintenance and overhaul, which ensure continuous system functioning and sustainable implementation of the full range of its features.
4. At the operation stage, control of application and maintenance systems is exercised.

Irrigation system operation stage

At the irrigation system operation stage, the following tasks are to be solved:

• arrangement of water use and water consumption;
• arrangement of primary accounting of water;
• control of the quality of irrigated areas, quality of groundwater and surface water;
• field inspection of technical condition of irrigation system components;
• governance and management of the operation stage.

Irrigation system maintenance stage

At the irrigation system maintenance stage, the following tasks are to be solved:

• material and technical support of irrigation system operation;
• carrying out of measures for restoration (improvement) of the quality condition of irrigated lands;
• carrying out of servicing of irrigation system components;
• implementation of technical maintenance of irrigation system components;
• implementation of repairs at the irrigation system components;
• governance and management of the maintenance stage.

To perform the works related to servicing (maintenance) and repair of system components at the maintenance stage, the operator is allotted special plots in the form of rights of way in accordance with the existing legislation. Land allotment standards and land use procedure are to be approved by regional legislative authorities.

Maintenance and repair of the irrigation system and its components

Maintenance and repair implies a package of measures for maintenance of the operational capability of the irrigation system and its components.

Repair of gravity irrigation systems. The goal of repair of the irrigation system is to restore it up to its designed condition. Improvement and development of the system (increase of the number of structures, operating equipment, mechanization and automation devices, etc.) can also be included in the repair plan. To determine the type and scope of repair works, a special commission carries out an inspection of canals and structures when water application process is over. Based on the inspection results, a damage statement is drawn up; this statement is used when developing design of routine maintenance or overhaul.

At routine maintenance, the following works are to be carried out annually: cleaning of canal from silt, vegetation, and landslides; filling dams with earth; repair of small damages of canals, flumes, structures, buildings, and other facilities. Preventive repair is a variety of routine maintenance which provides for regular cleaning of certain sections of canals and berms (banquettes) from soil and vegetation, liquidation of burrowing animals’ galleries, ice scabbling from structures, tightening of structures’ bolted joints, arrangement of heating works, cleaning of structures from garbage, removal of floating objects, lubrication of bearings, etc. This repair is executed without stopping the operation of the irrigation system.

Overhaul is executed periodically every certain number of years established according to relevant standards. It can be of integrated (across the entire system) or selective (in particular sections) type. Repair type is selected subject to a number of factors; this issue is to be solved individually for each system.

Overhaul should be started after vegetative irrigation is over and finished in spring. Cleaning of canals from sediment and vegetation is to be implemented in autumn and spring, and cleaning of structures that regulate water supply and distribution over the system is to be implemented in autumn-winter period and in spring prior to irrigation works. Communication lines, roads, buildings and auxiliary equipment are to be maintained over a year in accordance with the terms set out in the relevant production plan.

Emergency (reconstructive) repair is to be carried out in emergency cases (dyke breach, demolition of a structure, etc.) caused by acts of God (floods, ice jam) or violation of operating and maintenance rules. To speed up liquidation of emergency, this type of repair must be carried out on a round-the-clock basis with maximum mobilization of machinery and equipment, materials, and labour resources.