In the figure, these results are also compared with both the average irrigation demands reported by Lamaddalena et al. (2004) and the erogated water volume ranges publicly stated by the authority managing the Capitanata reclamation and irrigation district, plotted with red dashed-dotted lines and black dashed lines, respectively (for the orchards land-use class the consortium provides only the maximum value of the erogated water). As it was not possible to provide a direct validation of the method in terms of comparison between a simulated and a measured sample of actual evapotranspiration data all over the Capitanata region, we propose a comparison between the average irrigation deficit values derived by the presented method (equal to 347 and 323 mm in 1990 and 2006, respectively) and the value estimated by Lamaddalena et al. (2004) for almost the same land-use classes (equal to 326 mm). By this comparison, we obtained a fair agreement, with an error of 6.4 and −1.1% if 1990 and 2006 land-use are considered, respectively. The results are also summarized in Table 4, where the ratio between the calculated deficit and the mean water supply provided by the consortium is reported. Apart from the cases of complex cultivation patterns and orchards, which are in many cases complex mosaic crops and would therefore require deeper insight into the actual cultivations, the estimated deficit is always smaller than the erogated water supply. Moreover, by comparing the average irrigation deficit with the recommended water volumes given by the Consortium, values of global irrigation efficiency of 82 and 92% are obtained for 1990 and 2006 land-use, respectively. These values are consistent with the drip- and micro-irrigation practices that are commonly and widely adopted in the Capitanata irrigation district.

Table 4

Summary data of the calculated irrigation deficits for 1990 and 2006 land-use scenarios

Land-use class .	WS .			1990 land-use .					2006 land-use .
	Max .	Min .	Mean .	Area .	.	.	.	.	Area .	.	.	.	.
	.	.	.	% .	.	.	.	.	% .	.	.	.	.
Arable lands	400	250	325	64.88	286	299		0.92	68.26	293	315		0.97
Annual cr.	500	400	450	12.63	162	192		0.43	3.31	190	206		0.46
Vineyards	300	180	240	1.26	164	269		1.12	9.32	144	184		0.77
Complex patt.				15.26	731	700			8.01	732	665
Olive groves	300	200	250	1.25	154	183		0.73	4.53	184	198		0.79
Orchards			300	0.03	388	353		1.18	0.21	434	409		1.36
Other				4.71					6.35
Capitanata				100	287	347	122	0.82	100	287	323	122	0.92

Land-use class .	WS .			1990 land-use .					2006 land-use .
	Max .	Min .	Mean .	Area .	.	.	.	.	Area .	.	.	.	.
	.	.	.	% .	.	.	.	.	% .	.	.	.	.
Arable lands	400	250	325	64.88	286	299		0.92	68.26	293	315		0.97
Annual cr.	500	400	450	12.63	162	192		0.43	3.31	190	206		0.46
Vineyards	300	180	240	1.26	164	269		1.12	9.32	144	184		0.77
Complex patt.				15.26	731	700			8.01	732	665
Olive groves	300	200	250	1.25	154	183		0.73	4.53	184	198		0.79
Orchards			300	0.03	388	353		1.18	0.21	434	409		1.36
Other				4.71					6.35
Capitanata				100	287	347	122	0.82	100	287	323	122	0.92

Note: WS, water supply provided by the Capitanata consortium; Area, percentual coverage of each land-use class; ⁠, (Spatial) median value of the calculated deficit D; ⁠, Spatial average of D; 〈σ(D)〉, spatial average of the uncertainty ⁠. Abbreviated land-use classes are as follows: Annual cr., Annual and permanent crops; Complex patt., Complex cultivation patterns.

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