Final answer:
Dams play a crucial role in water management for human use, but they also come with ecological drawbacks, such as disrupting fish populations and altering water characteristics.
Step-by-step explanation:
Dams have historically been important for their ability to control water supply by collecting water during wet periods and storing it for use during droughts. They also provide benefits such as hydroelectric power, flood control, and recreational opportunities.
However, there are considerable ecological impacts associated with dams, including interference with the migration and spawning of fish like the salmon, changes in water temperature and chemistry, and altered flow characteristics. Many aging dams are now being considered for removal to restore naturally fluctuating water levels, improve water quality, and increase fish diversity.
In the Pacific Northwest, dam removal projects are expected to help restore salmon populations, a keystone species that contributes to nutrient transport in ecosystems. Similarly, along the Atlantic coast, dam removal has facilitated the return of anadromous fish species.
The outcomes of these large-scale ecological restorations from dam removal provide important data for future decisions on dam management. These removals signal a growing recognition of the importance of maintaining free-flowing rivers for ecological health.
Dam removal has become more prevalent to restore river ecosystems, especially to benefit keystone species like salmon in the Pacific Northwest and anadromous fish species along the Atlantic coast.