Great Lakes United signed onto this group letter sent to key members of U.S. Congress regarding the need to separate the Great Lakes and Mississippi River basins to protect our waters from Asian carp and other damaging species. The letter describes what hydrological separation is, what benefits will come from it, and what hydrological separation does not mean. It is a useful resource for anyone seeking information about how to successfully stop invasive species from entering the Great Lakes from the Mississippi river ecosystem. The document gives a clear outline of the economic and ecological benefits of hydrological separation and urges decision makers to take action to prevent further spread of invasive species.