The Washington Department of Ecology has issued the first four chapters of what will be a 13-chapter manual on how farmers and ranchers can best protect water quality.

The manual, “Voluntary Clean Water Guidance for Agriculture,” recommends “best management practices” and responds to a demand from the Environmental Protection Agency.

The Obama EPA complained in 2015 that Ecology’s overall plan to control polluted runoff was too vague when it came to farm chemicals, manure and soil.

Ecology convened an advisory group in 2018 to help it develop the guidance. Ecology is due to submit a new pollution-control plan to EPA by the end of the year.

Ecology, which has the power to fine polluters, will presume famers and ranchers who adopt the practices suitable for their operations are protecting water quality, said Ben Rau, Ecology’s watershed planning unit supervisor.

The manual will provide technical assistance, but not impose requirements, he said. “The recommendations are not a rule, hopefully that’s clear.”

Although not mandatory, the practices recommended in the guidance could shape farm practices. Ecology hopes to have the practices implemented, Rau said.

Ecology will use the guidance when working with farmers and ranchers to cure a pollution problem. The guidance also could influence funding for conservation programs. 

The first four chapters are on tillage and residue management, sediment control, pasture and rangeland grazing and riparian buffers.

Topics for future chapters include pesticides, irrigation, soil runoff and manure management. Ecology anticipates finishing the manual by 2025.

The guidance offers various practices from which farmers and ranchers can choose, though it identifies some preferred options, such as riparian buffers as wide as the height of the tallest trees along a stream.

The “default” buffer in Western Washington is 215 feet, while the default buffer in Eastern Washington is 150 feet. Ecology’s guidance cites the state Department of Fish and Wildlife.

Farm groups argue the wide buffers would be unnecessary and financially crippling.

The guidance also identifies installing fences to keep livestock out of the riparian buffers as a preferred option.