Related Rule
Spain
Practice Relating to Rule 54. Attacks against Objects Indispensable to the Survival of the Civilian Population
Section B. Attacks against objects used to sustain or support the adverse party
Spain’s LOAC Manual (1996) provides that the prohibition of attacks against objects indispensable to the survival of the civilian population does not apply if the adverse party uses such objects as sustenance solely for the members of its armed forces or in direct support of military action. However, any attack against such objects must not leave the civilian population without adequate food or water such as would cause it to starve or force it to move. 
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) and 4.5.b.(2)b).
Spain’s LOAC Manual (2007) states that the prohibition of attacks against objects indispensible to the survival of the civilian population does not apply if the adverse party uses such objects:
a. as sustenance solely for the members of its armed forces;
b. in direct support of military action (under no circumstances must the civilian population be left without adequate supplies of food or water, forcing it 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, § 3.3.c.(4); see also §§ 3.3.c.(4), 4.5.b.(2).(b) and 7.3.b.(2).(d).
Spain’s Penal Code (1995) punishes
anyone who, during an armed conflict, … attacks, destroys, removes or renders useless objects indispensable to the survival of the civilian population, unless the adverse Party uses the said objects in direct support of military action or as means of sustenance exclusively for members of its Armed Forces. 
Spain, Penal Code, 1995, Article 613(1)(c).
Spain’s Penal Code (1995), as amended in 2010, states:
1. Anyone who in the event of an armed conflict commits or orders to be committed any of the following acts shall be punished with four to six years’ imprisonment:
e. Attacking, destroying, removing or rendering useless objects indispensable to the survival of the civilian population, except where the adversary uses such property in direct support of a military action or exclusively as a means of sustenance for members of its armed forces;
2. … In all other cases mentioned in the above article, the higher sentence can be imposed when extensive and important destructions are caused to the property, objects or installations or [the acts] are of extreme gravity. 
Spain, Penal Code, 1995, as amended on 23 June 2010, Article 613(1)(e) and (2).