Related Rule
Ecuador
Practice Relating to Rule 42. Works and Installations Containing Dangerous Forces
Section A. Attacks against works and installations containing dangerous forces and against military objectives located in their vicinity
Ecuador’s Naval Manual (1989) provides:
Dams, dikes, levees, and other installations, which if breached or destroyed would release flood waters or other forces dangerous to the civilian population, should not be bombarded if the potential for harm to noncombatants would be excessive in relation to the military advantage to be gained by bombardment. 
Ecuador, Aspectos Importantes del Derecho Internacional Marítimo que Deben Tener Presente los Comandantes de los Buques, Academia de Guerra Naval, 1989, § 8.5.1.7.