**3. Approaching the problem from policy, economic and institutional perspective**

Since antiquity, the use of water in agriculture has been a basic element for the survival and economic and social progress of humanity. This explains why, since then, the irrigated area of the world has not ceased to grow [27], making irrigation a key element for feeding the planet. All over the world, Asia is irrigating 41% of the total cultivated surface, America 13%, Europe covering 9%, Oceania is irrigating the 7%, and Africa the 5%. The authors in [28] estimate a total irrigation potential of some 402 million hectares in developing countries, of which half is currently in use. In this way today, although the extension of global irrigation is limited since it represents only 7% of the world's useful agricultural area, this type of agriculture is a key element for feeding the planet [29]. Irrigation contributes exceptionally to social cohesion and stability since it generates a strong demand for labor and favors the commercial exchange of products and supplies, with the consequent economic flows (of consumption and savings) [30]. From north to south (Mediterranean area) the natural scarcity increases, being greater in the area of the Region of Murcia and Almería (Andalusia). They are the most productive irrigation but also the most deficient. In addition, this famine is aggravated by recurrent extreme events (droughts and floods) [31], that force us to think about management measures to prevent their effects and consequences [32]. Climate change projects a decrease for the year 2027 between 2 and 11% in the average contributions of the peninsular basins, whose effects will be greater in the most limiting or sensitive areas. The need for irrigation and its efficiency is indisputable [33].

#### **3.1 Politic, economic and institutional aspects**

The role of water in the economy covers various aspects from the analysis of the uses of water and its impact on the different economic sectors to economic instruments in the planning and management of water resources. In the first approach, the economics of water advocates determining the volume that is used, the forecast of future demand, its elasticity in relation to variations in other parameters, and the productivity of the different uses. The second focuses on the instruments of economic content that public authorities use in the planning and management of water resources. The National Agrarian Accounting Network of Spain indicates that for the year 2017 [34] the annual value of the production of an average hectare of irrigated land in Spain is 5.4 times higher than one of rainfed land (€5.576 compared to €1.030). Irrigation, in addition to promoting higher income, also makes it more secure by favoring the diversification of production and not depending on rainfall. In line with the greater profitability of the irrigation activity is the land value of the irrigated land. The transformation into irrigation on average multiplies by three the value of the land. In fact, in 2018 the average price of rainfed land for the whole of Spain stood at €9.447/ha, while irrigated land reached €28.444/ha [34]. Irrigated agriculture contributes more than half (64%, 16,000 million euros) to the value of the Spanish Final Agricultural Production, using less than a quarter (22.5%) of the national cultivated area (**Table 1**). The profitability and economic productivity of water are also different depending on the type of crop. 80% of irrigation water has returned between 0.02 and 0.60 €/m3 . It stands out that 19% of the volume used in irrigation is used for crops with very low profitability (less than €0.02/m3 . And only 1% for crops with returns greater than €3.00/m3 [36].

*Resilience of Irrigated Agriculture to Face the Challenges in Mediterranean Climatic Conditions… DOI: http://dx.doi.org/10.5772/intechopen.107882*


#### **Table 1.**

*Economic and social contribution of irrigation in Spain (year 2017) [35].*

In Spain and Portugal, an important part of irrigation is supplied by surface water, coming from the reservoirs of the great Iberian rivers. Therefore, it is from these river valleys, both those that flow into the Mediterranean and, mainly, those that flow into the Atlantic, that supply three-quarters of the Iberian irrigation. Irrigation is associated with high energy consumption. This makes irrigation communities especially vulnerable to energy prices with consequences on their economic situation [37–39]. Some prices are appraised and have a political component. Until a few years ago, there was a subsidized electricity rate for irrigation in Spain. For example, in the Segura Hydrographic Confederation for 2018, the different prices paid by the final user of water for irrigation are barely €0.033/m3 for river water, €0.10/m3 when water comes from the transfer (between river valleys), or €0.5/m3 if it comes from a water treatment plant [40]. In Portugal, great variability is also observed in the form of water pricing. The cost of water in most irrigation communities is based on area, and soil quality, because in some areas the hydrants do not have water meters; the most modern irrigable areas already have them and in these cases the water will be paid for the volume spent. Among those communities that charge water considering the irrigation area, they also differentiate their price considering the crops, and supposedly the water will be more expensive for the most profitable crops and with better soils. Thus, for example, the cost can vary between €77.5/ha (Cova da Beira Irrigation District) and €556.8/ha (Alqueva Irrigation District) on land cultivated with corn [41]. These prices include utilization fees and maintenance fees.

Special mention in Spain requires the cost of the Tajo Segura Transfer water. It is an aqueduct that transfers water from the Tagus River in an amount of 421 hm3 per year to the Segura River and therefore allows to reduce the scarcity of water in the Spanish southeast, where it is used with great efficiency. As a note to indicate that a few years the agreed total has been transferred and the transferred water covers not only irrigation needs but also other uses (urban). For some provinces of the Spanish southeast, the impact of the transfer is very high. It is enough, for example, to indicate that 62% of the agricultural area of the province of Alicante corresponds to areas that can be irrigated by transfer, while in Murcia it is 55% [42]. Transfers, like any other water policy measure, present economic costs, as well as environmental ones, which must be compensated. The total invoiced for the transfer represents 20% of all the income from fees and tariffs that are produced in all the Hydrographic Confederations of Spain, despite the fact that the transferred water is only 3% of the total water used

for irrigation in Spain [43]. As of 2017, a modification has been introduced in the rate that obliges water users to cover the construction costs, as well as the fixed costs of the infrastructure (of the entire infrastructure despite not transferring all the water agreed), increasing average costs.

#### **3.2 Unconventional waters use**

The scarcity of water determines and even forces the search for other non-conventional alternatives such as desalinated water or water treatment effluents so that water from treatment plants or desalination plants is used for irrigation, mainly mixed with well or surface water. Agriculture is the main user of reclaimed water and is reported to be used for this purpose in around 50 countries, on 10% of all irrigated land [44]. The main difficulty lies in the price, too high to be supported by farmers, and in the characteristics of the water obtained, due to the excess of salts, with the problems involved by the aquifers and soils. However, improving the quality of effluents is essential for their subsequent use, since water is a reusable resource that can have an almost unlimited life if it's well managed [45].

In 2010, the volume of unconventional resources in Spain rose to 4.540 hm3 / year, of which, those with effective use would add 450 hm3 of water coming from the reuse of treated water and 690 hm3 coming from desalination [46]. This amount has only grown and there are currently some 1.000 desalination plants in Spain with an installed capacity of 1.205 hm3 /year and 2.530 treatment plants that treat a flow of 3.375 hm3 /year, although their capacity is 30% higher [3]. Reclaimed water is one more resource within water management, and although it cannot be considered a conventional resource, it does have a key role in comprehensive water planning [47]. Despite this, its importance, at a quantitative level, is still very low, representing around 3% of the total available water resources. Although in practice it's found that the use of treated water is limited in agriculture basically because of its price ranges between €0.6/m3 and €0.8/m3 .
