(2) Unless required to do so by the provisions of the Federal Water Pollution Control Act, neither the Environmental Quality Commission nor the Department of Environmental Quality shall promulgate or enforce any effluent limitation upon nonpoint source discharges of pollutants resulting from forest operations on forestlands in this state. Implementation of any limitations or controls applying to nonpoint source discharges or pollutants resulting from forest operations are subject to ORS 527.765 and 527.770. However, nothing in this section is intended to affect the authority of the commission or the department provided by law to impose and enforce limitations or other controls on water pollution from sources other than forest operations.

(3) When the Environmental Quality Commission establishes instream water quality standards to protect designated beneficial uses in the waters of the state, it shall consider, where applicable, available scientific information including, but not limited to, streamflow, geomorphology and other factors representing the variability and complexity of hydrologic systems and intrinsic water quality conditions.

(4) When the Environmental Quality Commission establishes instream water quality standards, it will also issue guidelines describing how the department and the commission will determine whether water quality standards in waters affected by nonpoint source activities are being met. In developing these guidelines, the commission shall include, where applicable, those physical characteristics such as streamflow, geomorphology, seasons, frequency, duration, magnitude and other factors which represent the variability and complexity of forested and other appropriate hydrologic systems. [1991 c.919 §24; 2003 c.14 §302]