After more than six years of data gathering, studies and meetings, the Oregon Department of Environmental Quality has completed a plan to improve the Willamette River in three ways:

• Reduce bacteria in the water.

• Lower its temperature during the summer.

• And cut down on the traces of mercury found in the river.

The DEQ announced the plan's completion Friday from Portland, saying the order adopting it had been signed by Lauri Aunan, the agency's water quality administrator.

Some of the public hearings on the plan - known as the Willamette Basin Total Maximum Daily Load or TMDL - were held in Albany, including one last May.

The plan has implications for cities and industries along the river, as well as for farmers and foresters in the river basin, but exactly what they are is unknown.

Bacteria enter the river mainly with storm runoff from farm fields and city pavements, and the plan proposes to control that source better.

The plan seeks to lower the summertime river temperature to help migrating salmon and steelhead.

Holders of permits to discharge to the river may have to take steps to cool their discharge. Albany officials have talked with consulting engineers about a system of artificial wetlands in the Millersburg area to cool the output of the new $67 million wastewater treatment plant now under construction.

Dams operated by the Corps of Engineers also will have to adopt plans to manage the temperature of the water they release, the DEQ says.

As for mercury, the DEQ says 96 percent of it in the water comes from soil erosion and the air. Wastewater treatment plants contribute 4 percent.

Starting in 2007, some cities and industries will be asked to monitor mercury discharges and make plans to reduce them. By 2011 the DEQ expects to evaluate how effective the mercury measures have been.

The TMDL does nothing about another issue in the Willamette: the presence of traces of pesticides and other toxic chemicals.

The DEQ said it doesn't have the means to monitor toxics, to check whether they represent a danger to the public, or to work toward solutions.

The agency said it would ask the governor and Legislature to allocate money to identify the resources of toxic pollution that represent the greatest threat to public health and the environment, and then take steps to reduce them.