they felt like the needed to help the other people
The Sumerians couldn't take the heat so they made a irrigation system. The built canals that connect to the river but the problem was that there crops would get ruined from the floods the irrigation system.
You have not stated any problem.
salination of rivers
salination of rivers
i am not sure.
irrigation
According to Sumerian mythology, the gods An, Enlil, Enki and Ninhursanga created the black-headed people. The gods originally created humans as servants for themselves,but freed them when they became too much of a problem.
They build a kind of irrigation system
From wikipedia: "Irrigation" is an artificial application of water to the soil.The problem must be the Aral Sea shrinkage.The Aral Sea lost 90% of its volume within a few decades due to the intense irrigation of cotton and rice fields in Central Asia since 1960s.
you could be taking water from a river with bacteria or oil and chemicals
Soil salinity was the biggest problem for Sumerian farmers. Poorly drained irrigated soils, in an arid climate with high levels of evaporation, led to the buildup of dissolved salts in the soil, eventually reducing agricultural yields severely.
They used a shaduf.