Since the time that many of those dams that are worth demolishing for poor repairs/maintenance the federal government has also made it harder to get permits to

Since the time that many of those dams that are worth demolishing for poor repairs/maintenance the federal government has also made it harder to get permits to build new dams. They require more environmental studies up front. They require more study of downstream effects. Things like salmon, which are very sensitive to changes in river conditions, now have to be taken into effect earlier in planning stages and it is a growing requirement that any river to be dammed that include salmon hatcheries now has to plan for sub-projects like salmon runs (or with certain exceptions salmon cannons).