As stated on the website:

The Theme of the 2013 USSD Conference is Changing Times — The Challenges and Risks of Managing Aging Infrastructure under a New Financial Reality. The responsibility to create sustainable projects that are sensitive to the environmental, social, financial, geographical and political needs of the world's population is ever increasing. At the same time, the average age of our nation's existing dam infrastructure is rising, and in the next five years nearly 60,000 of the more than 80,000 dams in our national inventory will have exceeded their design life. In addition, many older dams that were constructed to protect agricultural interests are now protecting people and personal property, bringing new costly challenges for owners to modify the existing dam in response to the new role of the structure.