How might human activities change to compensate for a decrease in water supplies?

humans might build a factory.
humans might build drainage systems.
humans might extract more water from the ground.
human behavior does not change because of the water cycle.

Humans might extract more water from the ground.

Explanation:

Humans may face the situations of unavailability of water supply. Majority of the human population is dependent upon the source of water like oceans, lakes, rivers, ponds and wells for their water supply.

But in the scarcity of water from the drainage supply by the water body human population should search for a relevant alternative such as groundwater. Groundwater is the underground reservoir of water. The water in the groundwater reservoir accumulates from the sources such as rainfall, snow melting, river and oceanic water.

Humans should search for groundwater reservoir for compensating the scarcity of water.

The positive energy protons and negative electrons balance out.