Washington Criteria Development Progress
This page provides information about the progress Washington has made towards the development of numeric criteria and shows what statewide and site-specific criteria are currently in effect.
Note: The information on the tabs below reflects the information available on EPA’s
Water Quality Standards Repository. The criteria presented here will be updated as new water quality standards documents are posted to the Repository.
Numeric Criteria Development
The information presented below gives a summary of state progress towards the development of numeric criteria. The information comes from EPA’s “State Adoption of Numeric Nutrient Standards (1998-2008)” report, current water quality standards, program activity measures, and nutrient criteria development plans. Links to the Washington’s Nutrient Criteria Plan and state water quality standards are also provided.
Existing Numeric Criteria
| Waterbody Type | N | P | Chl-a | Clarity |
|---|---|---|---|---|
| Lakes and Reservoirs | W | |||
| Rivers and Streams | W | |||
| Estuaries | ||||
| Wetlands |
S = Statewide W = For selected waterbody N ⁄ A=Not Applicable
Note: See Statewide Criteria and Site-specific Criteria tabs for more information.
Links to Numeric Nutrient Criteria Plan and Existing Nutrient Criteria
Plan:
WQS: Washington Water Quality Standards
Department of Ecology State of Washington: Surface Water Quality Standards Exit
Milestone Information - Development of Statewide Numeric N/P Criteria
Milestone information updated July 2012.
Milestone |
Rivers and Streams | Lakes and Reservoirs | Estuaries and Coastal Waters | |||
|---|---|---|---|---|---|---|
| TN | TP | TN | TP | TN | TP | |
| Planning for criteria development | No date provided | No date provided | No date provided | No date provided | No date provided | No date provided |
| Collection of information and data | No date provided | No date provided | No date provided | No date provided | No date provided | No date provided |
| Analysis of information and data | No date provided | No date provided | No date provided | No date provided | No date provided | No date provided |
| Proposal of criteria | No date provided | No date provided | No date provided | No date provided | No date provided | No date provided |
| Adoption of criteria (EPA-Approved) | No date provided | No date provided | No date provided | No date provided | No date provided | No date provided |
TN: Total Nitrogen; TP: Total Phosphorus
Statewide Criteria
The information on this tab shows EPA-approved nutrient criteria for Washington’s waterbodies. The language presented below comes directly from state water quality standards and applies to all waterbodies within the state (unless a waterbody type or designated use is noted). Criteria applicable to specific waterbodies within the state can be found on the “Site-specific Criteria” tab. For more information, refer to the Washington water quality standards.
The following information reflects Washington’s 1997 water quality standards posted to the Water Quality Standards Repository as of November 2010.
WAC 173-201A-030 General water use and criteria classes.
The following criteria shall apply to the various classes of surface waters in the state of Washington:
(1) Class AA (extraordinary).
(a) General characteristic. Water quality of this class shall markedly and uniformly exceed the requirements for all or substantially all uses.
(c) Water quality criteria:
(viii) Aesthetic values shall not be impaired by the presence of materials or their effects, excluding those of natural origin, which offend the senses of sight, smell, touch, or taste.
(2) Class A (excellent).
(a) General characteristic. Water quality of this class shall meet or exceed the requirements for all or substantially all uses.
(c) Water quality criteria:
(viii) Aesthetic values shall not be impaired by the presence of materials or their effects, excluding those of natural origin, which offend the senses of sight, smell, touch, or taste.
(3) Class B (good).
(a) General characteristic. Water quality of this class shall meet or exceed the requirements for most uses.
(c) Water quality criteria:
(viii) Aesthetic values shall not be reduced by dissolved, suspended, floating, or submerged matter not attributed to natural causes, so as to affect water use or taint the flesh of edible species.
(4) Class C (fair).
(a) General characteristic. Water quality of this class shall meet or exceed the requirements of selected and essential uses.
(c) Water quality criteria - marine water:
(vii) Aesthetic values shall not be interfered with by the presence of obnoxious wastes, slimes, aquatic growths, or materials which will taint the flesh of edible species.
(5) Lake class.
(a) General characteristic. Water quality of this class shall meet or exceed the requirements for all or substantially all uses.
(c) Water quality criteria:
(viii) Aesthetic values shall not be impaired by the presence of materials or their effects, excluding those of natural origin, which offend the senses of sight, smell, touch, or taste.
Site-specific Criteria
The information on this tab shows EPA-approved site-specific nutrient criteria for Washington’s waterbodies. Criteria on this page apply only to the waterbodies listed below. Criteria applicable to all waterbodies within the state are found on the “Statewide Criteria” tab. For more information, refer to the Washington water quality standards.
The following information reflects Washington’s 1997 water quality standards posted to the Water Quality Standards Repository as of November 2010.
WAC 173-201A-030 General water use and criteria classes.
The following criteria shall apply to the various classes of surface waters in the state of Washington:
(6) Establishing lake nutrient criteria.
(a) The following table shall be used to aid in establishing nutrient criteria:
Ch. 173-201A-030, Table 1
| Coast Range, Puget Lowlands, and Northern Rockies Ecoregions: | ||
|---|---|---|
| Trophic State | If Ambient TP (ug/L) Range of Lake is: | Then criteria should be set at: |
| Ultra-oligotrophic | 0-4 | 4 or less |
| Oligotrophic | >4-10 | 10 or less |
| Lower mesotrophic | >10-20 | 20 or less |
| Action value >20 lake specific study may be initiated |
||
| Cascades Ecoregion: | ||
| Trophic State | If Ambient TP (ug/L) Range of Lake is: | Then criteria should be set at: |
| Ultra-oligotrophic | 0-4 | 4 or less |
| Oligotrophic | >4-10 | 10 or less |
| Action value >10 lake specific study may be initiated |
||
| Columbia Basin Ecoregion: | ||
| Trophic State | If Ambient TP (ug/L) Range of Lake is: | Then criteria should be set at: |
| Ultra-oligotrophic | 0-4 | 4 or less |
| Oligotrophic | >4-10 | 10 or less |
| Lower mesotrophic | >10-20 | 20 or less |
| Upper mesotrophic | >20-35 | 35 or less |
| Action value >35 lake specific study may be initiated |
||
Lakes in the Willamette, East Cascade Foothills, or Blue Mountain ecoregions do not have recommended values and need to have lake-specific studies in order to receive criteria as described in (c)(i) of this subsection.
WAC 173-201A-130 Specific classifications—Freshwater.
(107) Spokane River from Long Lake Dam (river mile 33.9) to Nine Mile Bridge (river mile 58.0). Special conditions: (a) The average euphotic zone concentration of total phosphorus (as P) shall not exceed 25 mg/L during the period of June 1 to October 31.