Agricultural Drought Indices - US Department of Agriculture

Figure 8. Water diversions of urban use for the metropolitan area of Valencia.
The saving measures initiated by the Irrigators Communities, as well as the opening of the first
phase of the modernisation of the Acequia ( irrigation ditch) Real del Júcar, allowed a very
important water saving in agriculture, with reductions higher than 50% in diversions of surface
water for irrigation in many irrigators communities. One of the most relevant agricultural areas in
the JRBA scope, the Júcar riverside in Valencia, significantly reduced irrigation diversions during
drought, with reductions higher than 50%.
Drought reached the Turia system in the year 2006/07, one year after having started in the Júcar
system. Nevertheless, and given the Júcar system’s situation, the agricultural areas of the Turia
system initiated some water saving measures during hydrological year 2005/06. One of the main
saving measures applied in the Turia system, once it entered the drought situation in 2006/07, was
the application of irrigation turns amongst irrigators communities of the traditional irrigations in
Turia, called “tandeos”(turns). “Tandeos” consisted in the alternative weekly irrigation between the
Real Acequia of Moncada and the irrigation of the Valencia Vega (fertile lowland), maintaining an
ecological flow in the river that allowed a significant saving in water use. The Real Acequia of
Moncada went from a water use of 90 hm 3 in the year 2004/05 to a use of 40 hm 3 in hydrological
years 2006/07 and 2007/08, which meant a water savings higher than 50% (Figure 9). The
irrigation in the Valencia Vega went from using 110 hm 3 in hydrological year 2004/05 to an
approximate use of 60 hm 3 in hydrological years 2006/07 and 2007/08, which meant an
approximate water savings of 50%.
The fourth and last group of measures consisted in alternative sources and additional resources
generation, the most important elements of which were the use of drought wells, re-circulation of
water in irrigation ditches (Acequias) through the so-called “re-pumping”, and the reuse of treated
waste water in agriculture.
The use of 135 drought wells and 25 re-pumping entailed an important control and surveillance
effort to minimise the possible impacts they might have on the environment. In this sense, to
homogenise the water extractions in the aquifer and avoid negative local effects, the maximum
level of extraction allowed for each well was limited, maximum volume of 1 hm 3 , or a group of wells
located in the same area, through the definition of exploitation sectors, maximum volume of 10 hm 3 .
The extracted water volume for irrigation of aquifers through drought wells was 40 hm 3 in the
irrigation campaigns of 2006 and 2007, and 25 hm 3 during the irrigation campaign of 2008 (Figure
10). The re-circulated water volume from re-pumping during drought, to optimise the use of water
in irrigation ditches, was 40 hm 3 during the irrigation campaign of 2006, 60 hm 3 during the
campaign of 2007 and 100 hm 3 during the campaign of 2008.
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