LA CONNER, Wash. (AP) — The Swinomish Tribe is threatening to sue the federal government to speed up estuary restoration — and salmon preservation — on the Skagit River delta. Much of the estuary has been drained and closed off with tide gates to facilitate agriculture, but such habitat is crucial for juvenile salmon. The tribe says that under an agreement reached in 2010, the Army Corps of Engineers isn’t supposed to grant construction permits to dike districts for work on the tide gates unless they first restore estuary habitat. But the tribe says that for the past five years, the Corps has been doing just that. The Army Corps said it is reviewing the tribe’s claims.