Lewis and Clark were looking for an east-west water route when they set out on their famous journey. They never found it. But 200 years later, a ceremony Sunday morning will complete their mission by symbolically joining together five mighty rivers.

With hundreds looking on from the Astoria Bridge, representatives from the Missouri Historical Society and the Nez Perce Tribe will pour water from the Mississippi, Missouri, Clearwater and Snake rivers into the mighty Columbia River from the deck of the Shamrock, a local charter boat.

Participants will board buses at the Clatsop County Fairgrounds at 7 a.m. that will ferry them to their viewpoint, high above the Columbia. The ceremony will start at 8 a.m.

"The bridge is the auditorium, the river is the stage," said Roger Rocka, chairman of Consider the Columbia. "Maybe it will be a beautiful day or maybe we'll experience what Lewis and Clark did," he said. Either way, the view from the bridge is spectacular.

The event will include a "living map,"to be created by a U.S. Coast Guard helicopter crew dropping flares at significant locations, starting at Grays Bay, where the river was so wide that the explorers thought they had reached the Pacific Ocean, and continuing to Dismal Nitch, Station Camp, Cape Disappointment, Smith Point and Fort Clatsop. Also featured will be a trade of beads for wapato, a root vegetable similar to a potato, and a show of streamers in many colors.

At the end of the ceremony, the Light Ship Columbia will sound its fog horn as a signal to all of the ships at anchor to sound theirs. During the chorus of fog horns, Rocka said event participants will join hands, symbolizing that "we are one country, native and non-native together."

During early brainstorming, it was suggested that people could form a human chain all the way across the four-mile-long bridge. Rocka said an early realization that it would take 4,500 people to stretch from shore to shore put an end to that plan.

The finale of the event will be a Coast Guard helicopter fly-over.

Tickets and advance reservations are required. Call 861-4403 for information.