Turkey 574 mm average rainfall for many years (below the world average of 800 mm) and has a semi-arid climate. Average annual precipitation rates by regions can be seen in Figure 2. In Central Anatolia, annual precipitation drops to 250

mm in the south of Lake Tuz and up to 2500 mm on the Eastern Black Sea coast. The lowest average precipitation occurs in the Central Anatolia region with 406 mm, and the highest average precipitation occurs in the Black Sea region with 696 mm.

Four climate types are observed in Turkey’s geography. These are Terrestrial, Mediterranean, Marmara (transition), and Black Sea climate. The Terrestrial climate is observed in 60% of the total area, including Central, Eastern, Southeastern Anatolia, and a part of Thrace. In this climate, precipitation is usually in the spring and winter months. Irregular and drought prevail during the plant development period.

The Mediterranean climate is effective in the south-facing parts of the Taurus Mountains in the Aegean Region and the Mediterranean Region. The summer season is hot and dry, and the winter season is warm and rainy. The Black Sea climate is effective in the coastal parts of the Black Sea Region and on the northern slopes of the mountains. It is rainy every season. Winters are cool on the coastal area, snowy and cold in the higher parts. Marmara (transition) climate is seen in the Marmara Region and the North Aegean region. It is a transition between the Black Sea and Mediterranean climates [19].

In the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report, it is stated that the general temperature increase in the Mediterranean Basin will reach 2˚C and the number of droughts, heatwaves, and extremely hot days will increase. In Turkey, the average annual temperature will be an increase between 2.5˚C and 4˚C in the near future, and this increase is expected to be 5˚C in Central Anatolia. It is stated that until the middle of the century, it is believed that many semi-arid regions (including the Mediterranean Basin) will experience a decrease in water resources due to climate change. The annual river flow and water availability will decrease in the Mediterranean Basin. Sectors affected by drought will include agriculture, water supply, energy production, and health.

Regionally, large increases in irrigation water demand are predicted as a result of climate changes. Besides this report, other national and international scientific studies, Turkey’s near future warmer, arider and shows rainfall will be more uncertain. Researches suggest increased temperatures will also affect the physical, chemical, and biological properties of freshwater lakes and rivers, with predominantly adverse impacts on many individual freshwater species, community composition, and water quality [20].

The increment rate in the water requirements due to the population increase, global warming, and climate change negatively affect the water resources especially water used in agriculture. In addition, the decrease in precipitation and the increase in temperature, due to global warming, will change the types of land and water use [21]. Changes in precipitation and temperature in Turkey will affect water resources, agricultural production, human health, natural disasters, and economic growth. It can be said that the ECHAM5 simulation points to two regions where significant changes will occur in precipitation. These regions are the Mediterranean and Southeastern Anatolia, where precipitation is supposed to decrease significantly after 2040, and the Black Sea Regions, where precipitation is predicted to increase [22]. Therefore, as for food security and water management, “National Water Plan 2019-2023” and “National Climate Change Action Plan 2011-2023” have been prepared by the Ministry of Agriculture and Forestry [23], and Ministry of Environment and Urbanization [24]. In these documents, strategic targets and actions have been determined. The Turkish Government has adopted an approach based on the watershed for the preparation of river basin protection and management plans. The World Bank (WB) has been supporting these efforts in different ways [25].

Turkey’s water policies are determined by various legal regulations. These policies are implemented by various ministries and executive units [26]. Turkey’s water policies are characterized by a desire to achieve energy independence, ensure food security through increased agricultural production, and to meet the demand for water of other sectors [27]. According to the Constitution of the Republic of Turkey (Art. 168), to develop and manage water resources, belong to the state authority. According to the Turkish Civil Code (Art. 756), surface and groundwater resources cannot be private property, except for springs from private land. However, there are user rights for irrigation, fishing, thermal, energy, industry, mining, domestic use, etc. State Hydraulic Works (SHW) gives water use permits in Turkey [26].

The main purpose is to improve water and soil resources in Turkey SHW, in the year 1953 (6200 Law No.) has been established and organized along 25 major river basins in the country. It acts as the competent authority in the planning, implementation, and management of water investments. Among the duties of SHW, are dams, irrigation canals, and the construction of flood prevention barriers, drying of swamps, and supplying drinking water to big cities [17].

General Directorate of Land and Water (Soil-Water), which was established in 1960 (law no 7457), was transferred to the General Directorate of Rural Services (KHGM) in 1985. In 2005, as part of the government’s decentralization program, KHGM was abolished (Law No. 5286), and its duties regarding land and water affairs were transferred to the Special Provincial Administrations-SPAs (Law No. 5302). Before this date, large irrigation investments were made by SHW, and small irrigation investments of less than 500 liters per second were made by Toprak-Su and later by KHGM [26]. However, with the transfer of this duty to the Special Provincial Administrations, a gap has arisen in this regard, but the government has not made regulations on this issue yet.

Four of the river forms the watersheds in Turkey is reaching the sea beyond the country’s borders. These are the Euphrates, Tigris, Coruh, and Aras rivers. The Euphrates and Tigris rivers are rises in the Eastern Anatolia region of Turkey. Then they flow through Syria and Iraq and reach the sea in the Persian Gulf. The Euphrates has a total length of 2800 km and only 971 km of the river is within Turkey’s border. The Tigris has a total length of 1900 km of which 523 km lie within Turkey. Çoruh, one of the fastest rivers in the world, flows 431 km inland Turkey and after flowing 21 km before discharging into the Black Sea in Georgia.

The Aras river, one of the largest rivers of the Caucasus, is 1072 km long and reaches the Caspian Sea from Azerbaijan. Aras River rises in Turkey and after 300 km the river forms some countries’ borders such as Turkey-Armenia and Azerbaijan-Iran border.

Other transboundary rivers are the Evros/Meriç River, which comes from Bulgaria and Greece and reaches the Aegean Sea, and the Asie River, which comes from Lebanon and Syria and reaches the Mediterranean [27].

Other rivers that make up the water basins are as follows. The length of Kızılırmak, the longest rivers reaching the Black Sea, is 1355 km, Sakarya is 824 km and Yeşilırmak is 519 km. The length of the Büyük Menderes from the river reaching the Aegean Sea is 548 km, the Gediz River is 401 km and the Küçük Menderes is 175 km. From the river reaching the Mediterranean, Seyhan is 560 km, Ceyhan is 509 km and Göksu is 260 km long [16]. Turkey’s territory has 25 major river basins showing a big change compared to the average annual rainfall, evaporation, and runoff characteristics [27]. Rivers and water basins in Turkey are given in Figure 3.

As shown the largest catchment areas are the Euphrates-Tigris, respectively, Kızılırmak, Sakarya and Konya inland basin (Table 2). The total drainage area of the Euphrates-Tigris basin is 184,918 km². They provide 29.2% of the total surface water supply. Kızılırmak basin, the second largest basin, has a drainage area of 78.180 km². Konya inland basin (53,850 km²), which is one of the major basins, is also among the basins with the least runoff.

The use of groundwater is an important alternative in places where surface water

is lacking for agricultural production. In Turkey, 78% of the irrigation water comes from surface sources and 22% from underground sources. Turkey throughout 1428 ha of land is irrigated by groundwater. The operation of groundwater investments made by the state in arid regions through irrigation cooperatives is being carried out successfully as an important model. Groundwater is densely extracted from wells drilled in Konya, Isparta, Eskişehir, Kayseri, Edirne, Samsun, and İzmir provinces and used for irrigation.

65 billion km³ of annual rainfall in Turkey (14%) are infiltrated underground. 25 million km³ of this rise back to the ground as usable water with springs. There are 18 million km³ of water retractable from the underground [17]. The underground water investments for irrigation are costly to be used for opening the wells; setting up the motto-driven pumps, electrification to the facilities, and constructing canals and sheds for the facilities.

Southeastern Anatolia Project (GAP) is located in the Euphrates-Tigris river basin, covering Adıyaman, Batman, Diyarbakır, Gaziantep, Kilis, Mardin, Siirt, Şanlıurfa, and Şırnak nine provinces having approximately 10% of the total population and area of Turkey. The main objective of GAP 20% of Turkey’s irrigable land (1.7 m ha) of fertile soil that makes up Southeast Anatolia with the Euphrates and Tigris rivers to irrigate. Only 30% of the irrigable areas in the Region have been opened to irrigation. With this project, it is aimed to open the remaining 70% (1.1 m ha) to irrigation. Within the scope of the GAP Project, the construction of 20 irrigation projects, which will irrigate 279,000 ha of land, continues [17].

According to a study, It was seen that wheat areas decreased, while corn and cotton areas increased along with putting into practice the irrigation in the region. Gross production value is defined as an increase of 84% per hectare [31].

Konya Plain Project (KOP) is implemented in the Konya inland basin with an area of three m ha in the Central Anatolia Region. The KOP project covers eight provinces consisting of Konya, Aksaray, Karaman, Niğde, Kırıkkale, Kırşehir, Nevşehir, and Yozgat. With the project, 1.1 m ha of land was planned to be irrigated and 397,000 ha (36%) of land were opened to irrigation so far. About 25% is irrigated with groundwater by irrigation cooperatives. The remainder (31%) also is at the investment or project stage. After the GAP, It is the largest irrigation investment project in Turkey [17].

Because the groundwater is intensely used in the region, the groundwater levels of the wells are gradually falling down. The most important benefit of the KOP project will be recharging artificially groundwater reservoirs by diverted water supply from the neighbor watersheds. According to a survey conducted in the irrigated area, the average wheat yield of 2300 kg/ha has been identified that of increase to 4300 kg/ha [32].

Irrigating the dry agricultural lands may ensure reducing the fallowed areas that will increase crop yield and change the crop pattern towards the industrial crops as a response. At the completion of the project wheat production and accordingly yield is estimated to increase 87%, which will be a significant contribution to food security.

East Anatolian Project (DAP) involved in 15 provinces covers 23% of the surface area of Turkey. Within the scope of the project, it is planned to irrigate 1.4 m ha of agricultural land in the region. With the DAP Project, 35 irrigation projects have been completed and 525,000 ha (37%) of land has been opened to irrigation. Investments in 44 irrigation projects are also continuing [17].

According to a survey conducted in Erzurum, the average wheat yield of 3780 kg/ha has been identified that as an increase to 4960 kg/ha [33]. At the completion of the project improved irrigation, and enlarged irrigated areas in the region will increase the wheat yield by 31% as a significant contribution to food security.

Eastern Black Sea Project (DOKAP) has nine provinces and constituting 7.5% of the surface area of Turkey. These provinces are Samsun Tokat, Giresun, Istanbul, Ordu, Gümüşhane, Bayburt, Rize, and Artvin. 41% of the irrigation projects in the region are completed, 17% are at the construction stage, and 42% are at the planning or project stage.

Thrace Development Project (TRAGEP) covers the provinces of Edirne, Kırklareli, Tekirdağ, and Çanakkale. Within the scope of the project, 89 projects were completed in the 2003-2020 period and 137,000 ha of land started to be irrigated [17].

The Ministry of Agriculture and Forestry (MoAF) donates 50% of the cost of investment to the modern-irrigation systems to extend the use of newer techniques among the farmers. It is highly appreciated by the farmers as well that these new systems are significantly more efficient than the older systems. According to MoAF, even with the 50% financial incentive, some farmers are not able to start investments due to limited capital sources. A subsidy loan program of which the interests for the loans are subsidized by the MoAF has started to help these farmers to overcome the limited capital source difficulties.

MoAF has seen land consolidation as a tool to accelerate irrigation investments and reduce costs in recent years. Combining land consolidation with irrigation projects saves 40% on irrigation investments. When agricultural production is carried out on dry land, small and scattered parcels, costs increase. The Turkish government has proposed a number of changes in how inheritance rights will be managed in the land consolidation and irrigation program [34].

After 1993, SHW transferred the maintenance and management of irrigation canals that deliver water to approximately 2 m ha of land to local administrations (village authorities or municipalities) and water user associations [26]. Irrigation investment of SHW in Turkey is generally operating by irrigation associations (372), cooperatives (269), municipalities (143), and village authorities (189).

Irrigation associations and cooperations decide on the following matters: the starting date of irrigation; the ending date of irritation; the order of irrigation and the price of irrigation. The dates of irrigation will be declared to the farmers in advance. These are also responsible for maintenance services.

The most significant cost factor for underground water irrigation cooperations is energy. The share of energy costs in total production costs according to plant varieties and irrigation methods can rise up to 17% [35]. The irrigation cost is collected at the end of the harvesting season. But farmers are not willing to pay the price of energy. So energy debt accumulates and leads to various problems every year. The payment willingness of energy costs has been found to decrease depending on a young age and small family [36].

Irrigation cooperatives (1458) irrigate 497,000 ha of land with groundwater. The provinces that provide the most irrigation with groundwater are Eskişehir (192,000 ha), Isparta (72,000 ha), Izmir (38,000 ha), Aydın, Bursa, Diyarbakır, Adana, and Edirne.

Climate and irrigation possibilities are the two major factors, which affect land use in all regions, directly [38]. According to SHW calculations, 12 m ha of agricultural land in Turkey can be irrigated by modern irrigated systems. However, only 6.4 m (53.3%) of the irrigable land has been opened for irrigation. Water consumption in agriculture is predicted to increase from 43 billion km³ to 64 billion km³ depending on the expansion of irrigated areas. However, considering the increasing water demand of other sectors, it is estimated that the share of agriculture in total water use will decrease from 72% to 64% [17].

The crop pattern where the lands are opened to irrigation has been completely changed from monoculture production into polyculture production. As a consequence, crop yield, accordingly, farmers’ income is increasing markedly. While cereals (wheat, barley) are produced and fallow are made in dry agriculture, the production pattern in irrigated agriculture is sugar beet, corn, cotton, wheat, vegetables, and fruits. Grain yield in irrigated areas increased to an average of 4.6 tons/ha, cotton to 4 tons/ha, corn to 12 tons/ha. With irrigation, yield increase was achieved in cereals by 166%, in legumes 239%, in sugar beet 95%, in cotton 292%, in corn 564%, in fruit 117%, in citrus 130% and in vegetables 134%. While the production value in dry agriculture due to rainfall was 1990 TL/ha on average, it increased to 11,850 TL/ha with irrigation. The contribution of irrigated agriculture (6.4 m ha) to food security in Turkey is calculated as 2/3. In other words, Turkey’s agricultural production 2/3 is made in irrigated areas [17].

The Turkish government, which foresees that irrigation in arid areas is of vital importance in terms of food security, has planned to open 8.5 million hectares of cultivated land to irrigation by 2023 and targeted the Gross Agricultural Production Value as 150 billion US $ [39]. However, since the necessary irrigation investments could not be made, it is not considered possible to reach the targets set by the government. Developments regarding agricultural production value according to TURKSTAT data are given in Figure 5.

The agricultural production value in Turkey, while US $ 37.4 billion in 1998,

US $ 21.3 billion in 2001 with the economic crisis’ has fallen. Production value then increased rapidly and reached US $ 78.7 billion in 2010. However, due to the depreciation of the Turkish lira, it decreased to US $ 51.4 billion in 2019. It is seen that the agricultural production value decreased after the year 2010. This situation is evaluated as a result of the reflection induced by macroeconomic factors and climate change effects on agriculture in Turkey [40].

Turkey’s self-sufficiency rate in food security is given in Table 3. Generally, wheat, sugar, fruits (except walnuts), and vegetables are sufficiently produced from agricultural products. However, especially corn, sunflower, rape, dry bean, and lentil cannot be produced sufficiently. Even in the last ten years, the insufficiency of legumes has increased. In the 2007-2017 period, there was a 26% increase in sunflower production in self-sufficiency rates, and a decrease of 31.2% and 34.9% in chickpea and red lentil production, respectively [37]. While the self-sufficiency rates of citrus fruits and grapes increased in the fruit group, there was no significant change in the vegetable group.