In a gesture as grand as the landscapes it would protect, key leaders of Washington's congressional delegation have introduced legislation intended to protect Olympic Peninsula forests and rivers from logging, dams and other development.

Three years in the negotiating, The Wild Olympics Wilderness & Wild and Scenic River Act of 2012 was introduced Thursday by U.S. Sen. Patty Murray and U.S. Rep. Norm Dicks, D-Bremerton. The bill is a far cry from the original version proposed in 2010 by conservationists, but still takes big steps to permanently protect some of the Olympics' most beloved landscapes.

"The amazing natural treasures in the Olympic Peninsula are among the crown jewels of our state, and the Wild Olympics proposal will build on the strong foundation of conservation that has been laid down over generations," Murray said in a news release.

The legislation would create 126,554 acres of new wilderness on Olympic National Forest lands, including 93,959 acres of old-growth trees at least 160 years old, and 107,982 acres of mature trees older than 80 years. Some trees that would be protected are more than 700 years old.

The proposal also would create 19 new Wild and Scenic Rivers in the Olympic National Park, Washington Department of Natural Resources Lands, and within Olympic National Park.

Wild & Scenic designation prohibits federally licensed dams. It also creates a planning process to manage the land within a quarter-mile corridor in contiguous stretches of federal and state lands along the river to protect a river's wild, scenic or recreational values.

Private lands would not be affected unless owners are supportive. The legislation includes no condemnation authority.

The bill is intended to maintain and improve recreational access through the public planning process called for under the Wild & Scenic Rivers designation.

Rivers slated for protection include the Elwha within Olympic National Park, the Lyre, Dungeness (including Gray Wolf River tributary), Big Quilcene, Dosewallips, Duckabush and Hamma Hamma, as well as portions of the South Fork Skokomish, Quinault, Queets, Hoh and Sol Duc.

The primary effect of the legislation is to prevent future administrations from opening up ancient forests and wild rivers to new logging, road building, mining, drilling or dams.

The proposal steps back from the big plans from its earlier versions, because of objections raised by timber companies concerned about loss of timberlands, and tribes that feared loss of access for treaty-protected hunting.

The North Olympic Timber Action Committee has said the designation would result in the loss of 113 to 226 timber jobs, and the Central Committee of the Clallam County Republican Party last year passed a resolution against the proposal.

The new bill dropped the entire 37,000 acres of proposed additions to the national park and removed 11,300 acres of harvestable timber lands, including second growth plantations from the proposed wilderness. The bill also added 7,400 acres of old growth and mature trees to the proposed wilderness.

Lynda V. Mapes: 206-464-2736 or lmapes@seattletimes.com. On Twitter @lyndavmapes.