Drivers were temporarily turned away from a busy roadway in Somerset County after flooding from overnight rain. The Griggstown Causeway, which crosses the Millstone River to connect River Road in Montgomery Township to Canal Road in Franklin, has seen high water levels following the heavy rain Thursday night into Friday morning. At it's highest point so far, the the river reached 10.82 feet at approx. 9:45 a.m., above the flood stage of 10 feet, according to NOAA data. The Griggstown Causeway typically closes to traffic when the gauge reaches approx. 9 feet. When the water reaches 10 feet, River Road in Montgomery Township begins to flood near the Griggstown Causeway, according to the NOAA. The flood warning expired at 10:30 a.m., but Somerset County Public Safety encourages residents to continue to heed any remaining road closures they may encounter.