SAVANNAH, Ga. - The federal government is pumping an additional $2.5 million into pre-construction work that's needed before crews could begin deepening the shipping channel to Savannah's seaport. Officials announced Wednesday the money is being allocated from $741 million in discretionary funds the Army Corps of Engineers has to improve navigation. It's a relatively small amount of the estimated $600 million needed to deepen the Savannah River channel from 42 to 48 feet. It also comes as South Carolina lawmakers are trying to stop the project, arguing it would cause irreparable environmental damage to the river it shares with Georgia. The Army Corps said the new federal funds would be spent on detailing construction and environmental mitigation plans needed before dredging could begin in Savannah, which has the nation's fourth busiest container port.