EPA scientists are working collaboratively with the Army Corps of Engineers (USACE) to understand the drivers of algal bloom dynamics, using statistical modeling to test for significant spatial and temporal trends. The data set is being provided by the USACE and includes phytoplankton taxonomy, water chemistry, and hydrology measures from 20 reservoirs in Ohio, Kentucky, and Indiana.  The monitoring program has been in place since 1978 and includes multiple sampling sites and depths within each reservoir. The data set will be used to test multiple hypotheses regarding the drivers of harmful algal blooms in reservoirs.