A grand opening celebration for a new education center and four cabins at Cottonwood Canyon State Park on the John Day River about 50 miles southeast of The Dalles is set for September 18.  The grand opening celebration will include presentations, a ribbon cutting and a tour of the new facilities, which include a 1,500-square foot Experience Center that will serve as a classroom for outdoor education and a reservable event space.  The $2.5 million project also includes four cabins and a new restroom facility with showers.  The Experience Center was designed in part to support Eastern Oregon University’s Cottonwood Crossing Summer Institute, a week-long residential field study course for high school students held each June.  It was largely built thanks to donors and fundraising by the private nonprofit Oregon State Parks Foundation, which contributed $600,000 in money and donated products.  The grand opening event will be from 1 p.m. to 4 p.m. on September 18.