The ancient sumerians modified their
environment to increase food production by
(1) building terraces
(2) removing rain forests
(3) digging irrigation canals
(4) developing chinampas

3. digging irrigation canals.

Sumerians lived in present day Iraq which is mostly desert. Being arid with periods of rain, the region of Sumeria was difficult to cultivate crops. The Sumerians used a system of canals and gates to create watered plains with flooding and then closed them off during growing seasons.