To Think the Unthinkable: Why Large Mainstem Dams Shouldn't Always Stay up

Dams harness the power of water for many uses, but also disrupt ecological connectivity.  This is particularly true of mainstem dams, which block the routes of migratory species and hold back sediments.  In terms of societal well-being, we have traded one set of benefits for another.  But are these traded benefits necessarily the best choices?  We provide examples of losses of migratory production, and examine the Conowingo Dam on the Susquehanna River as a case study.  Generally, large dam removals constitute “wicked problems” as constituencies arise on both sides of the issue, and the tendency is to try to remediate rather than remove.