OAR 340-056-0100


“Assimilative Capacity” means the ability of a receiving water to accept a quantity of a water quality constituent and still meet water quality standards. See also “Loading Capacity” below.


“Biennial Water Quality Status Assessment Report” is the biennial report prepared by the DEQ to meet the requirements of Section 305(b) of the federal Water Quality Act.


“EQC” or “Commission” means the Oregon State Environmental Quality Commission.


“Director” means the Director of the Department of Environmental Quality.


“DEQ” or “Department” means the Oregon State Department of Environmental Quality.


“Instream Water Right” means a water right held in trust by the Water Resources Department for the benefit of the people of the state of Oregon to maintain water in stream for public use. An instream water right does not require a diversion or any other means of physical control over the water. (See ORS 537.332 (Definitions for ORS 537.332 to 537.360)(2)).


“Loading Capacity (LC)” means the greatest amount of loading that a water can receive without violating water quality standards. (See OAR 340-041-0002 (Definitions)(31)).


“Load Allocation (LA)” means the portion of a receiving water’s loading capacity that is attributed either to one of its existing or future nonpoint sources of pollution or to natural background sources. Load allocations are best estimates of the loading which may range from reasonably accurate estimates to gross allotments, depending on the availability of data and appropriate techniques for predicting loading. Wherever possible, natural and nonpoint source loads should be distinguished. (See OAR 340-041-0006(19)).


“ODFW” means the Oregon Department of Fish and Wildlife.


“Outstanding Resource Water” means those waters designated by the Environmental Quality Commission where existing high quality waters constitute an outstanding state or national resource based on their extraordinary water quality or ecological values, or where special water quality protection is needed to maintain critical habitat areas. (See OAR 340-041-0002 (Definitions)(44)).


“Parks” or “Parks Department” means the Oregon Department of Parks and Recreation.


“Pollution” means such contamination or other alteration of the physical, chemical or biological properties of any waters of the state, including change in temperature, taste, color, turbidity, silt, or odor of the waters, or such radioactive or other substance into any waters of the state which either by itself or in connection with any other substance present, will or can reasonably be expected to create a public nuisance or render such waters harmful, detrimental, or injurious to public health, safety, or welfare, or to domestic, commercial, industrial, agricultural, recreational, or other legitimate beneficial uses or to livestock, wildlife, fish or other aquatic life, or the habitat thereof. (See OAR 340-041-0006(9)).


“Public Benefit” means a benefit that accrues to the public at large rather than to a person, a small group of persons or to a private enterprise. (See ORS 537.332 (Definitions for ORS 537.332 to 537.360).)


“Public Uses” include, but are not limited to:




Conservation, maintenance and enhancement of aquatic and fish life, wildlife, fish and wildlife habitat and any other ecological values;


Pollution abatement; or


Navigation. (See ORS 537.332 (Definitions for ORS 537.332 to 537.360)(4).)


“Receiving Stream” or “Receiving Water” means a water of the state into which wastes are discharged.


“Reserve Capacity” means that portion of a receiving stream’s loading capacity which has not been allocated. The reserve capacity includes the loading capacity which has been set aside as a margin of safety.


“Total Maximum Daily Load (TMDL)” means the sum of the individual WLAs (for point sources), LAs (for nonpoint sources), background sources and reserve capacity. TMDLs are based on the loading capacity, or assimilative capacity of the receiving water. TMDLs can be expressed in terms of either mass per time, toxicity, or other appropriate measure. (See OAR 340-041-0006(21)).


“Water Quality Limited” means one of the following categories:


A receiving stream which does not meet instream water quality standards during the year or defined season even after the implementation of standard technology;


A receiving stream which achieves and is expected to continue to achieve instream water quality standards but utilizes higher than standard technology to protect beneficial uses;


A receiving stream for which there is insufficient information to determine if water quality standards are being met with higher than standard treatment technology, or where through professional judgment the receiving stream would not be expected to meet water quality standards during the entire year or defined season without higher than standard technology. (See OAR 340-041-0006(30)).


“Waste” means sewage, industrial wastes, and all other liquid, gaseous, solid, radioactive, other substances which will or may cause pollution or tend to cause pollution of any water of the state. (See OAR 340-041-0006(13)).


“Waste Load Allocation (WLA)” means the portion of a receiving water’s loading capacity that is allocated to one of its existing or future point sources of pollution. WLAs constitute a type of water-quality based effluent limitation. (See OAR 340-041-0006(20)).


“Water Quality Standards” means provisions of State or Federal law which consist of a designated use or uses for the waters of the United States and water quality criteria for such waters based upon such uses. Water quality standards are to protect the public health or welfare, enhance the quality of water and serve the purposes of the Clean Water Act. (See 40 CFR 130.2(c).)


“WRD” means Water Resources Department.
[Publications: Publications referenced are available from the agency.]
Last Updated

Jun. 8, 2021

Rule 340-056-0100’s source at or​.us