Irrigation is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been developed by many cultures around the world. Irrigation helps to grow crops, maintain landscapes, and revegetate disturbed soils in dry areas and during times of below-average rainfall. In addition to these uses, irrigation is also employed to protect crops from frost, suppress weed growth in grain fields, and prevent soil consolidation. It is also used to cool livestock, reduce dust, dispose of sewage, and support mining operations. Drainage, which involves the removal of surface and sub-surface water from a given location, is often studied in conjunction with irrigation.
Pothundi Dam is an irrigation dam near Pothundi village in the Palakkad district of Kerala state, India. Constructed in the 19th century, it is considered one of the oldest dams in India. It provides irrigation to an area of 5,470 hectares in the Palakkad district and drinking water supply to the Nemmara, Ayalur, Melarcode Panchayat. An unusual feature of the earth dam is the core wall, which is built with a mixture of jaggery and quick lime.
The Indian rivers interlinking project is a proposed large-scale civil engineering project that aims to effectively manage water resources in India by linking rivers using a network of reservoirs and canals to enhance irrigation and groundwater recharge and reduce persistent floods in some parts and water shortages in other parts of the country. India accounts for 18% of global population and about 4% of the world's water resources. One of the solutions to solve the country's water woes is to link its rivers and lakes.
A johad, also known as a pokhar or a percolation pond, is a community-owned traditional harvested rainwater storage wetland principally used for effectively harnessing water resources in the states of Haryana, Rajasthan, Punjab, and western Uttar Pradesh of North India, that collects and stores water throughout the year, to be used for the purpose of recharging the groundwater in the nearby water wells, washing, bathing and drinking by humans and cattle. Some johads also have bricked or stones masonry and cemented ghat.
Water resources and irrigation infrastructure in Peru vary throughout the country. The coastal region, an arid but fertile land, has about two-thirds of Peru's irrigation infrastructure due to private and public investment aimed at increasing agricultural exports. The Highlands and Amazon regions, with abundant water resources but rudimentary irrigation systems, are home to the majority of Peru's poor, many of whom rely on subsistence or small-scale farming.
Lift irrigation is a method of irrigation in which water is not transported by natural flow, but is lifted with pumps or surge pools etc.
Mexico, a classified arid and semi-arid country, has a total land area of 2 million square kilometres, 23% of which is equipped for irrigated agriculture. The agricultural sector plays an important role in the economic development of the country accounting for 8.4 of agricultural gross domestic product (GDP) and employing 23% of the economically active population. Irrigated agriculture contributes about 50% of the total value of agricultural production and accounts for about 70% of agriculture exports. Mexico's government initiated a number of structural reforms in the water sector aimed to introduce modern water management and irrigation.
Irrigation in the Dominican Republic (DR) has been an integral part of DR agricultural and economic development in the 20th century. Public investment in irrigation has been the main driver for irrigation infrastructural development in the country. Irrigation Management Transfer to Water Users Associations (WUAs), formally started in the mid-1980s, is still an ongoing process showing positive signs with irrigation systems in 127,749 ha, being managed by 41,329 users. However, the transfer process and the performance of WUAs are still far from ideal. While WUAs show a significant increase in cost recovery, especially when compared to low values in areas under state management, a high subsidy from the government still contributes to cover operation and maintenance costs in their systems.
The environmental impact of irrigation relates to the changes in quantity and quality of soil and water as a result of irrigation and the subsequent effects on natural and social conditions in river basins and downstream of an irrigation scheme. The effects stem from the altered hydrological conditions caused by the installation and operation of the irrigation scheme.
River linking is a project of linking two or more rivers by creating a network of manually created reservoirs and canals, and providing land areas that otherwise does not have river water access and reducing the flow of water to sea using this means. It is based on the assumptions that surplus water in some rivers can be diverted to deficit rivers by creating a network of canals to interconnect the rivers.
Water resources management in modern Egypt is a complex process that involves multiple stakeholders who use water for irrigation, municipal and industrial water supply, hydropower generation and navigation. In addition, the waters of the Nile support aquatic ecosystems that are threatened by abstraction and pollution. Egypt also has substantial fossil groundwater resources in the Western Desert.
Irrigation in Iran covers 89,930 km2 making it the fifth ranked country in terms of irrigated area.
Costa Rica is divided into three major drainage basins encompassing 34 watersheds with numerous rivers and tributaries, one major lake used for hydroelectric generation, and two major aquifers that serve to store 90% of the municipal, industrial, and agricultural water supply needs of Costa Rica. Agriculture is the largest water user demanding around 53% of total supplies while the sector contributes 6.5% to the Costa Rica GDP. About a fifth of land under cultivation is being irrigated by surface water. Hydroelectric power generation makes up a significant portion of electricity usage in Costa Rica and much of this comes from the Arenal dam.
Water resources management in Nicaragua is carried out by the National water utility and regulated by the Nicaraguan Institute of water. Nicaragua has ample water supplies in rivers, groundwater, lagoons, and significant rainfall. Distribution of rainfall is uneven though with more rain falling on an annual basis in the Caribbean lowlands and much lower amounts falling in the inland areas. Significant water resources management challenges include contaminated surface water from untreated domestic and industrial wastewater, and poor overall management of the available water resources.
The Kankai River is a trans-boundary river flowing through the hills of Ilam and the plains of the Jhapa District in Nepal. It begins at the confluence of the Mai Khola and Deb Mai Khola rivers.
The Polavaram Project is an under construction multi-purpose irrigation project on the Godavari River in the Eluru District and East Godavari District in Andhra Pradesh. The project has been accorded National project status by the Central Government of India. Its reservoir back water spreads up to the Dummugudem Anicut and approx 115 km on Sabari River side. Thus back water spreads into parts of Chhattisgarh and Odisha States. It gives major boost to tourism sector in Godavari Districts as the reservoir covers the famous Papikonda National Park, Polavaram hydro electric project (HEP) and National Waterway 4 are under construction on left side of the river. It is located 40 km to the upstream of Sir Arthur Cotton Barrage in Rajamahendravaram City and 25 km from Rajahmundry Airport.
The Salaulim Dam is located on the Guleli River, a tributary of the Zuari River in Goa, India. It is an integral component of the Salaulim Irrigation Project which envisages benefits of irrigation and drinking water supply. The dam is a composite earth+masonry dam of 42.7 metres (140 ft) height with a water spread area of 24 km2 (9.3 sq mi).
The Bhadra Dam or Lakkavalli Dam, which has created the Bhadra Reservoir, is located on the Bhadra River a tributary of Tungabhadra River. Bhadra Dam is located in the border of Bhadravathi and Tarikere, in the western part of Karnataka in India. The benefits derived from the reservoir storage are irrigation with gross irrigation potential of 162,818 hectares, hydro power generation of 39.2 MW, drinking water supply and industrial use. The dam commissioned in 1965 is a composite earth cum masonry structure of 59.13 metres (194.0 ft) height with length of 1,708 metres (5,604 ft) at the crest level, which submerges a land area of 11,250.88 hectares.
Lakhwar-Vyasi Dam project on Yamuna River, includes under-construction Lakhwar Dam and Power Station, Vyasi Dam, Hathiari Power Station and Katapathar Barrage, near the Lakhwar town in Kalsi block of Dehradun district of Uttarakhand in India, for the purpose of irrigation of 40,000 hectare land and total 927 MW hydroelectric power generation. "Lakhwar Dam" is a gravity dam near the Lohari village with 300MW power generation capacity. "Vyasi Dam" will be built 5 km downstream along with 120 MW "Hathiari Power Station" further 0.5 km downstream. "Katapathar Barrage", with the maximum ponding water level at 514.5m elevation, will be built further 2.75 km downstream of the Hathiari Power Station to supply the water to stakeholder states. Project will hold 580 million cubic metres water during monsoon and release into Yamuna during dry months.
The Kanjirapuzha Dam, a masonry earth dam built for providing irrigation to a Cultural Command Area (CCA) of 9,713 hectares, is located in the Palakkad district in the Indian state of Kerala. The reservoir, which has three islands within it, also has an established commercial fisheries development programme operated by the Fisheries Department.
