Question 13 Dams provide hydropower, drinking water, increased agricultural output through irrigation, easier water transport, and flood control. But like most human alterations of ecosystems, dams present tradeoffs. Which of the following are negative tradeoffs that come with damming a river? Dams slow the movement of water, increasing sedimentation, lowering levels of dissolved oxygen, and changing patterns of nutrient transport Dams contribute to changes in downstream coastal ecosystems Dams affect migratory patterns of fish species All of the above