‘A valley is stricken with drought’ is the event that would most likely cause a competition for water.
Step-by-step explanation:
Water scarcity is getting worse nowadays, we have to find a solution for the lack of water in a global level. It is true that the event of a valley is stricken with drought is most likely cause scarcity for water. Recent analyses of United Nations shows that the water availability will surpass by 40% in 2030.
Basically valley have the natural water flow and they usually start with the shallow waters of Mountain Rivers, and then increase the speed as they welcome new journey to an even larger river or to the ocean. Drought is a persistent phase of dry weather with months or even years without a rainfall in an area. If the event is prolonged there will be a shortage of water supply and it leads to competition for water.