Massachusetts has more than 300 dams, most of which were built in the 1800s to power mills. These aging dams have outlived their original purpose and are now deteriorating, threatening public safety and river health. Massachusetts, through regulatory efforts and community involvement has become one of the leading states in removing dams and restoring the health of the rivers in the state. This session will cover a broad range of topics associated with dam removals to provide a better understanding of the history, costs and benefits, and design and construction details for the removal of dams. In the first half, Beth Lambert will discuss the evolution of dam removal in MA, the landscape of regulations and partnerships that make dam removal possible, and the primary technical and social challenges to dam removal. In the second half, Nick Nelson will cover some of the basics of the science, engineering, and construction that is involved in the projects. He will provide a review of fluvial geomorphic principals, summarize the data typically required to design the removal of a dam, and discuss some of the challenges with hydraulic modeling and sediment management and transport.