Соответствующая норма
Spain
Practice Relating to Rule 54. Attacks against Objects Indispensable to the Survival of the Civilian Population
Section C. Attacks in case of military necessity
Spain’s LOAC Manual (1996) provides that the prohibition of attacks against objects indispensable to the survival of the civilian population does not apply where derogation of the prohibition is required by imperative military necessity. 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Publicación OR7-004, 2 Tomos, aprobado por el Estado Mayor del Ejército, Division de Operaciones, 18 March 1996, Vol. I, § 4.5.b.(2).b).
The manual allows one derogation from the prohibition of attacks against objects indispensable to the survival of the civilian population if the defence of the national territory against the danger of an invasion imperatively so demands. 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Publicación OR7-004, 2 Tomos, aprobado por el Estado Mayor del Ejército, Division de Operaciones, 18 March 1996, Vol. I, § 3.3.c.(4).
Spain’s LOAC Manual (2007) states:
Objects indispensable to survival may be destroyed, removed or rendered useless as a method of defence against invading forces if there is an “imperative military necessity”. 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Tomo 1, Publicación OR7–004, (Edición Segunda), Mando de Adiestramiento y Doctrina, Dirección de Doctrina, Orgánica y Materiales, 2 November 2007, § 2.4.c.(1); ); see also §§ 3.3.c.(4) and 4.5.b.(2).(b).
The manual further states:
However, if such objects are attacked, it must be ensured that the civilian population is not deprived of food or water to the extent that it suffers starvation or is forced to move. 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Tomo 1, Publicación OR7–004, (Edición Segunda), Mando de Adiestramiento y Doctrina, Dirección de Doctrina, Orgánica y Materiales, 2 November 2007, § 4.5.b.(2).(b).