WASHINGTON — The Biden administration took action Thursday to restore federal protections for hundreds of thousands of small streams, wetlands and other waterways, undoing a Trump-era rule that was considered one of that administration’s hallmark environmental rollbacks. At issue is a regulation sometimes referred to as “waters of the United States,” or WOTUS, that defines the types of waterways qualifying for federal protection under the Clean Water Act. The regulation has long been a point of contention among environmental groups, farmers, homebuilders, lawmakers and the courts. The announcement by the Environmental Protection Agency and the Army reinstates a rule in...