How does the irrigation system cause a decrease in water quality?

Irrigation systems can decrease water quality through runoff, which often carries fertilizers, pesticides, and sediments into nearby water bodies. This can lead to nutrient pollution, causing algal blooms that deplete oxygen and harm aquatic life. Additionally, over-irrigation can cause soil salinization, further degrading water quality. Finally, the alteration of natural water flow can disrupt ecosystems, compounding the negative effects on water quality.