MIAMI — For years, Everglades restoration engineers and scientists have been working on ways to control the ripple effects when they finally start returning healthy water flows to the marsh.

Increased suburban flooding has long been the big concern from raising water levels in the Everglades but a critical plan now on the fast track surprisingly poses the opposite problem.

Initial computer modeling for the $1 billion plan, which the U.S. Army Corps of Engineers is rushing to complete by year’s end, suggests the proposed re-plumbing of assorted levees, canals and pumps could divert too much water from a well field that supplies Miami-Dade County with much of its drinking water. At certain times of the year, it also could reduce already meager freshwater flows to southern Biscayne Bay that have turned much too salty.