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Agricultural Water Management And Climate Change In Turkey

Congress: 2015
Author(s): Aynur Fayrap, Şerife Pınar Güvel

Aynur Fayrap, Şerife Pınar GÃŒvel
General Directorate of State Hydraulic Works, 6th Regional Directorate of State Hydraulic Works



Keyword(s): Sub-theme 17: Climate change, impacts and adaptation,
Abstract

There is a broad agreement that climate change has major effects on water resources. Irrigation water accounts for more than 70% of global water withdrawals (IWMI, 2007). On the basis of existing trends in agricultural water-use efficiency and yield gains, it is projected that agricultural withdrawals will need to increase to more than 2 900 km3/yr by 2030 and almost 3 000 km3/yr by 2050. This indicates a net increase of 10 percent between now and 2050(FAO, 2011). But climate change might change this figure in the future. Water management will play an important role on especially preventing water scarcity derived from climate impacts. In current situation, agriculture is by far the biggest user of fresh water in Turkey. Up to recent years, irrigation networks were designed as open systems and traditional irrigation methods are extensively used in Turkey's agriculture. But for recent years, closed irrigation systems have been planned, designed and applied. As is known, pressurized irrigation is vital for raising of irrigation performance and using water efficiently. Thus, negative impacts of climate change on water resources may be mitigated, to some extent, by decreasing excessive agricultural water use and evaporation. As a result of climate change, precipitation may decrease in some regions and water stored in lakes and reservoirs may suffer increased losses due to evaporation, reducing the water available for irrigation in Turkey. The long term average (1950-2003) precipitation and temperature of Turkey are about 646 mm and 13°C respectively(Saylan, 2014). According to results from different climate change scenarios, a decrease of 5% in mean annual precipitation can be expected for 2030. In 2050, mean annual precipitation decreases by approximately 10%. Although decreases are expected in precipitation in all months, the sharp decreases in spring and autumn are significantly important, because summers in the region are already dry. Water security of the country is likely to be under risk due to the reasons caused by the factors such as difficulties in controlling water reserves resulting from geographical structure, unbalanced distribution of rainfall. The available water per capita in Turkey is less than the world average. Furthermore, as it is shown at Figure 2., it is estimated by the experts that the amount of available water will likely to be less than 1000 m3/capita/year in 2023 (Turkey Water Report, 2009). Contrary to the common belief, Turkey is not a country rich in water reserves and approximately 73% of water resources of Turkey is allocated for agricultural purposes. Under these circumstances, effective water utilization and water saving closed irrigation systems are the most critical issues to be considered. Selection, design and implementation of best irrigation methods based on land characteristics and implementation of proper irrigation programs will provide an effective water resource utilization and preservation. At the same time, improvements in irrigation performance and water management are critical to ensure the availability of water both for food production and for competing human and environmental needs. The quantity of irrigation water applied in pressurized irrigation systems such as drip, sprinkler, mobile sprinkler were less than surface irrigation methods for about the same optimum yields. Research results showed that drip irrigation method was the most effective method as compared with the other methods(Sener, 2010). Total land resources of Turkey is 77.95 million hectares and 28.05 million (35.98%) of it used as agricultural lands. Currently irrigated land area of Turkey is about 5,73 million hectares and that constitutes 22% of total irrigable land resource. There is an excessive water use problem in irrigation practices of Turkey. Main reason for this excessive water use in irrigation schemes is high water loses in networks. Then, water distribution networks minimizing the water delivery and distribution lose should be constructed. For this purpose, pressurized and piped systems should be selected instead of open canal and canalette systems during the construction of new irrigation systems. Farm efficiency in traditional irrigation systems e.g., border or furrow irrigations is about 60%. If leakage, evaporation and operational losses are included, efficiency becomes 50%. Climate change affects the function and operation of existing water infrastructure -- including drainage and irrigation systems-- as well as water management practices. While water resources reduce due to climate change, on the other hand, excessive water application in irrigation can also lead to losses due to surface runoff and deep percolation. In some cases these losses may be reused elsewhere, in other cases they are irrecoverable due to saline sinks, or high costs. Low irrigation efficiencies may lead to environmental problems such as water logging, high water table, salinity and alkalinity problems. In Turkey, approximately 77% of total area is irrigated by surface irrigation methods (furrow, border, etc). The remaining part is irrigated with pressurized irrigation methods (sprinkler 15% and trickle 8%). Instead of surface irrigation methods, if sprinkler and drip irrigation methods are utilized, sprinkler irrigation increases water efficiency from 60% to 80% and drip irrigation increases water efficiency up to 95%(anon., 2014). Climate change affects the function and operation of existing water infrastructure -- including drainage and irrigation systems-- as well as water management practices. While water resources reduce due to climate change, on the other hand, excessive water application in irrigation can also lead to losses due to surface runoff and deep percolation. In some cases these losses may be reused elsewhere, in other cases they are irrecoverable due to saline sinks, or high costs. Low irrigation efficiencies may lead to environmental problems such as water logging, high water table, salinity and alkalinity problems. Current water management practices may not be enough to be copied with the impacts of climate change on water supply reliability. An efficient water management system must be established. And integrated and long term water management plans should be implemented based on watershed. In this study, impacts of climate change over agriculture and irrigation were evaluated and recommendations were provided for sustainable water management in agriculture for Turkey. 1. FAO, 2011. THE STATE OF THE WORLD'S LAND AND WATER RESOURCES FOR FOOD AND AGRICULTURE. 2. IWMI (2007), Water for Food, Water for Life: A Comprehensive Assessment of Water Management in Agriculture, London: Earthscan, and Colombo: International Water Management Institute. 3. Saylan, 2014. POTENTIAL IMPACTS OF CLIMATE CHANGE ON AGRICULTURE IN TURKEY. http://www.cost734.eu/reports-and-presentations/7th-management-commitee-meeting/potential-impacts-of-climate-change-on-agriculture-in-turkey 4. Sener, S. 2010. GLOBAL CLIMATE CHANGE AND ITS EFFECTS ON IRRIGATION IN MEDITERRANEAN REGION - WATER AND ENERGY SAVING IRRIGATION SYSTEMS AND SOME RELEVANT RESEARCH RESULTS, ISHS Acta Horticulturae 922: XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on CLIMWATER 2010: Horticultural Use of Water in a Changing Climate. 5. Turkey Water Report, 2009. p:1-59.General Directorate of State Hydraulic Works, TURKEY.

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