(WASHINGTON) — The Trump administration was expected to announce completion as soon as Thursday of one of its most momentous environmental rollbacks, removing federal protections for millions of miles of the country’s streams, arroyos and wetlands. The changes, launched by President Donald Trump when he took office, sharply scale back the government’s interpretation of which waterways qualify for protection against pollution and development under the half-century-old Clean Water Act. A draft version of the rule released earlier would end federal oversight for up to half of the nation’s wetlands and one-fifth of the country’s streams, environmental groups warned.