Water Wisdom: Preparing the Groundwork for Cooperative and Sustainable Water Management in the Middle East

Editors’ Summary

Agricultural Water Use Efficiency The average requirement of water per unit of land area in Israel has decreased from 8,700 m3 /ha in 1975 to 5,500 m3 /ha in 1995. At the same time agricultural output increased twelve-fold, while total water consumption by the sector remained almost constant. Such increased water use efficiency has been accomplished via a number of supporting factors, including precision irrigation technology, irrigation water control, and water policy covering water allocations, metering, and pricing. Micro-irrigation and Fertigation The wide-scale adoption of low-volume irrigation systems (e.g., drip, microsprinklers ) and automation has increased the average efficiency (relative amount of water utilized by crops) to 90% as compared to 64% for furrow irrigation or 75% for sprinklers. Development of drip irrigation technology that allows low-flow application of water uniformly throughout agricultural fields, along with the application of this technology in agricultural water management, has been a cornerstone in Israel’s advancements in water use efficiency. With drip irrigation, water is supplied when and where crops can utilize it. In addition, a significant advantage of drip-irrigation systems lies in their ability to supply nutrients as well as water. Such fertilizing via the irrigation system (fertigation) allows precision nutrient management and results in increased efficiencies of both fertilizer and water as higher yields are achieved. Today, further irrigation efficiency is being attempted by regulating water application to each individual plant. Root volume water and nutrients can be further controlled by proper irrigation management where soil and crop types are matched with dripper spacing, flow rate, and irrigation frequency in order to ultimately achieve maximum plant water uptake and growth with minimum water. Water Supply for Agriculture in Israel 219 Million cubic meters per year Year 2000 1000 Total water supply Wastewater reuse Wastewater reuse Wastewater reuse 0 1980 1990 2000 2010 Agriculture 460 430 30 Domestic and municipal Industry Figure 9.8 Wastewater reuse as part of the overall water balance (drought years excluded). From Shelef 2001. Irrigation Water Control Drip irrigation systems are readily automated. Computers allow real-time response in the operation of the irrigation systems, providing precision, reliability, and savings in manpower as water application is controlled remotely. Sensors are also used to provide information on soil moisture and plant water status, allowing automatic operation of systems and providing tools that assist to avoid unnecessary excess or deficits in water applications. Water Allocations, Metering, and Pricing While traditionally subsidized, water prices for agriculture are graded according to water quality. Subsidies to agriculture that were approximately 50% in 1992 decreased to around 20% in 1996 and continue to be decreased. Water charges for various consumers are set by a parliamentary committee. Agricultural water is allocated by quota and purchased at prices that increase as use of the quota increases. The purpose of this price structure is to combine support for agriculture with economic efficiency and encouragement of conservation. Conservation is further encouraged by pricing brackish and recycled water (table 9.18) lower than the freshwater and according to level of quality (Kislev 2001, Nativ 2004). alon ben-gal 220 Table 9.18 Agricultural water prices Agricultural use U.S.$/cubic meter Freshwater Up to 50% of user’s allotment 0.39 Next 30% of user’s allotment 0.45 Rest of amount allocated 0.59 Average 0.45 Tertiary recycled wastewater (Shafdan) 0.24 Secondary effluent 0.18 Brackish water 1.9–2.65 dS/m 0.25 2.65–3.4 dS/m 0.24 3.4–4.1 dS/m 0.21 4.1–4.8 dS/m 0.20 4.8–5.2 dS/m 0.19 .5.2 dS/m 0.17 Source: Israel Water Authority, 2008. Note: US$1  3.5 NIS. A Critical Look at the Conflicting Roles of Agriculture in Israel’s Water Economy Israel’s history suggests that agriculture plays multiple, sometimes conflicting, roles in Israel’s water economy. First, irrigation technology and advancements in water use efficiency and agricultural productivity are banners of national pride. Israel is fast to promote its agricultural water-related achievements and even to attempt to export expertise and technology. At the same time, agriculture, as the largest single sector consuming water, is held responsible for water shortages in the country—both ongoing and those occurring periodically due to drought. Irrigation water is the...