Want to meet those legendary call ladies?The Arc of Southwest Washington may be best known to this community for those sweet-as-sugar volunteers who phone residents politely asking after clothing donations. The donations “are our bread and butter,” said Michael Piper, the executive director of the Arc, a homegrown agency that caters to people with disabilities of all sorts.Now, you can meet the people who butter that bread. The call ladies will be on hand — along with staff, friends and clients — for the Arc’s 77th anniversary celebration and open house, set for 5-7 p.m. July 1 at 6511 N.E. 18th St. The event is free and open to the public; there will be barbecue, tours, program descriptions — and heartfelt invitations for volunteers to get involved.Greenway tourBefore all that, you can work up some appetite by touring Burnt Bridge Creek with the Arc and the Vancouver Watersheds Alliance, which have teamed up to launch weekly explorations of the greenway from a trailhead right behind the Arc’s 18th Street home. Those tours always get under way at 4 p.m. Monday. Plenty of parking is available at the Arc and the adjacent trailhead.“It’s been a great marriage between folks with disabilities and our environmental community, who teach us how to take care of the watershed. There’s been quite a lot of turnout for that,” Piper said.Then return to the Arc for food and celebration. “We want everyone to meet our staff and the people we serve, and help us celebrate,” Piper said.