Question

What did irrigation works include?

Answer 1

Hint: It is the method of applying controlled amounts of water to plants at appropriate intervals. In dry areas and during times of less than normal rainfall, it helps to grow agricultural crops, sustain habitats and revegetate disturbed soils. It is the artificial application of water to the soil through the various systems.

Complete answer:
Canals, wells, tanks and artificial lakes included in irrigation works.
Canals are channels of rivers or artificial waterways for the conveyance of water or for the service of vehicles for water transport. They can assist with irrigation as well. As an artificial version of a river, it can be thought of. Under air pressure, canals bear free surface flow.
In order to access liquid resources, usually water, a well is an excavation or structure formed in the ground by digging, driving, or drilling. A water well for access groundwater in underground aquifers, is the oldest and most common kind of well.
Water tanks are used to store water for use in many purposes, such as drinking water, irrigation, fire control, cultivation for both plants and animals, chemical processing, food storage as well as many other uses.
In several nations around the world, man-made reservoirs, also called artificial lakes, are an important source of water. It is possible to use the stored water for irrigation, drinking water after purification or for energy production.

Note: People used iron for clearing woods about many years ago.
This allowed the domestication, that is, agriculture, of plants. Because of this, irrigation has also become a must.
Canals, wells, tanks, and artificial lakes were a part of the irrigation work.