The expansion will add just over 7,000-sf to the 33,000-sf museum. The 38-year-old Columbia River Maritime Museum, one of the major attractions in this city perched at the mouth of the Columbia River, receives upwards of 70,000 visitors annually despite its out-of-the-way location in the northwest corner of the state. The expansion was designed by the Fletcher Farr Ayotte architecture firm from Portland, and McCarthy, one of the nation's largest domestic general contractors, will lead the construction effort, says museum spokeswoman Zoe Ulshen.

Despite backhoes that have been moving dirt on the site for a few days now, Rob Mangold, president of the museum's board of trustees, will mark the start of construction this afternoon at a 4p.m. groundbreaking ceremony. The Museum features more than 7,000 artifacts, and the lightship Columbia, a National Historic Landmark. In addition to the new features already mentioned, a new cinema will show a 12-minute orientation documentary on the history of the Columbia River from its tributaries to the bar. A bigger meeting room, dividable into two, and a cafe also are part of the expansion plans.

There will be no changes to the permanent exhibition rooms toward the rear of the building, which will remain open throughout construction. The Great Hall just beyond the existing entrance will close for three months next fall to allow for completion of the expansion. Funded solely by ticket sales and donations, the Museum relies on supporters to advance programs, and expand collections and facilities. The biggest contributor to the expansion project is the (Fred) Meyer Memorial Trust.