Final answer:
Constructing a new dam is likely to cause significant ecosystem destruction, affecting local and downstream habitats, altering river ecology, impacting fish migration, and causing habitat loss for various species. Therefore, the correct option is B
Step-by-step explanation:
The environmental damage MOST likely to result from constructing a new dam for agricultural water storage is the destruction of ecosystems both in the dam’s location and downriver. The creation of a reservoir leads to habitat loss for forest, fish, and amphibian species. The damming of rivers changes water flow, temperature, chemistry, and sediment loads, significantly altering the river's ecology and physical characteristics which can eliminate populations adapted to natural flow regimes and seasonal changes. This can also have an impact on fish migration, particularly species like salmon that need to travel upstream to spawn, which can be hindered by dams, potentially leading to declines in fish populations. In addition, habitat destruction can extend to areas used by indigenous groups, and although projects like small run-of-the-river dams can lessen environmental impacts, large hydroelectric projects have been associated with significant ecological disruptions.