As river dams age, communities wrestle with how to how to repair and remove them, and a lack of scientific understanding on the subject doesn't help.
How does dam removal affect river systems? Could it cause catastrophic flooding? And how will it change river ecology, river flow, bank buildup or erosion?
Geographer Frank Magilligan of Dartmouth College and his team, who have done extensive research on new Hampshire's Ashuelot River, use laser-based tools and GPS analysis to collect data on such questions, measuring things like topographic elevation, river flow and erosion. Science correspondent Miles O'Brien reports for the National Science Foundation's* latest Science Nation.
For the record, the National Science Foundation is an underwriter of the NewsHour.
